The effects of organic and inorganic fertilizers on the...

Appendix B1

The effects of organic and inorganic fertilizers and lime on species-richness, plant functional traits and ecological indicator values in the vegetation of semi-natural hay meadows F.W. KIRKHAM*†, J.R.B. TALLOWIN‡, G.M. HOPPÉ,§, R.A. SANDERSON $, A. BHOGAL† and CHAMBERS, B.J. † †ADAS Consulting Ltd, Woodthorne, Wergs Road, Wolverhampton WV6 8TQ, UK; ‡Institute for Grassland and Environmental Research, North Wyke, Okehampton, Devon EX20 2SB; §Applied Plant Science, Department of Agriculture and Rural Development, Queens University, Newforge Lane, Belfast BT9 5PX, UK and $Centre for Life Sciences Modelling, Porter Building, St. Thomas Street, University of Newcastle upon Tyne NE1 7RU, UK

Summary

1. Maintenance of biodiversity in semi-natural grasslands, and enhancement of biodiversity in grasslands that have undergone agricultural improvement, require sensitive management of fertility and soil pH. Vegetation responses to fertilizers and lime applied in a six-year study at six mesotrophic grassland sites are described in terms of species-richness and several composite variables derived from plant ecological characteristics and indicator values.2. Randomised block experiments were established in paired unimproved and semi-improved hay meadows in Cumbria, Monmouthshire and Fermanagh. Treatments were: farmyard manure (FYM) applied at 6, 12 and 24 tonnes ha-1 annually or every third year; inorganic fertilizers giving the same amounts of N, P and K as the two higher FYM rates; and lime, alone or with 12 t ha-1 FYM applied annually or intermittently. Two rates of organic pellet fertilizer and inorganic equivalents were also tested at Welsh sites and at the semi-improved site in Cumbria.3. Responses differed between sites, but annual FYM at the highest rate was apparently not ecologically sustainable at any site. The unimproved (MG3b) site in Cumbria was both the most species-rich and the most sensitive to treatments. Results suggested that FYM supplying more than 6.0-7.5 kg N ha-1 per year, averaged over the six years, might ultimately lead to reduced species-richness. The amount currently in use there (12 t ha-1 annually) represents the upper limit of this range. At the Welsh unimproved site, low to moderate FYM inputs were apparently more beneficial than higher or nil inputs. Results were less conclusive in the Fermanagh unimproved meadow, but suggested that the fairly high inputs of inorganic fertiliser currently used there should be reduced or replaced by moderate levels of FYM. 4. Contrary to expectations inorganic fertilizers were, in general, less detrimental to vegetation quality than equivalent levels of FYM. Liming tended to maintain species-richness and to increase the proportion of herbs, but the effect of liming in conjunction with FYM varied between sites. 5. Synthesis and applications. Moderate levels of fertilizer and/or liming are sustainable in semi-natural meadows, although optimum levels of nutrient input vary according to past inputs and current soil fertility.

Key-words: farmyard manure, inorganic fertilizer, lime, vegetation

*Present address and Correspondence: Francis Kirkham, Ecological Research and Consultancy, Far View, Nymet Rowland, Crediton, Devon EX17 6AL, UK (fax +44136383187; email [email protected]

Introduction

Dramatic losses of unimproved grasslands have occurred since the 1930s, with associated severe declines in many less common and specialist plant species (Ratcliffe, 1977, 1984; Nature Conservancy Council, 1984; Green, 1990; Hopkins, 1990; Rich and Woodruff, 1996). Reviewing grassland surveys carried out between 1930 and 1984, Fuller (1987) estimated that lowland grasslands of conservation interest had declined by 97% over this period. Whilst a greater proportion of the existing grassland in upland areas of England and Wales is of conservation interest, the uplands have also shown a progressive decline in species-rich grassland (Hopkins and Wainwright, 1989). The greatest overall change has been in the number of herb-rich hay meadows (Nature Conservancy Council, 1984). A national survey showed that only 4.9% of surviving hay meadows could be regarded as species-rich and only 1.6% were worthy of protected area status (Nature Conservancy Council, 1984). These results paint a very different picture to that described by Tansley (1939), who showed that in the late 1930s most hay meadows contained a wide variety of grasses and herbs. Furthermore, more recent surveys have shown that loss of species diversity in UK grassland is continuing, and that the species which are declining include those which are already nationally scarce and associated with unimproved meadows (Barr et al., 1993). Initially, most of the UK losses were due to ploughing and drainage, but inorganic fertilizer use has increased over the same time scale, improving even old and undrained grassland (Fuller, 1987). Few extensive surveys have been carried out on the continent of Europe, but it is recognized that a widespread decline in species-rich grassland has also occurred there (van Duuren, Bakker & Fresco, 1981; Ellenberg, 1988; Losvik, 1988; Bakker, 1989; Willems, 1990; Berendse et al., 1992; Garcia, 1992). The UK Biodiversity Steering Group (1995) has designated Lowland Meadows and Upland Hay Meadows as two distinct priority habitats for conservation and each has a Biodiversity Action Plan (UK Biodiversity Group, 1998). Lowland Meadows primarily embrace MG5 (Cynosurus cristatus – Centaurea nigra grassland), MG4 (Alopecurus pratensis – Sanguisorba officinalis floodplain meadow) and MG8 (Cynosurus cristatus – Caltha paustris flood pasture) communities of the National Vegetation Classification (NVC – Rodwell, 1992). The Upland Hay Meadow habitat comprises the single NVC community MG3, Anthoxanthum odoratum – Geranium sylvaticum grassland (Rodwell, 1992). More than 5000 hectares of MG5 grassland have been recorded in pure form in England and Wales, representing over 70% of semi-natural neutral grassland (Blackstock et al., 1999). Pure forms of MG3 comprised 754 hectares, whilst those of MG4 and MG8 comprised 340 and 234 hectares respectively. The MG8 community is primarily associated with grazing on alluvial floodplains, but MG3, MG4 and most MG5 communities have resulted from traditional management by hay making in July-August followed by grazing (Rodwell, 1992). Work has shown that the integrity of MG3 communities in upland hay meadows is very dependant upon the maintenance of these traditional practices without the use of inorganic fertilizers (Smith & Jones, 1991; Smith & Rushton, 1994; Smith et al., 1996). The same management regime, in combination with seed addition, has been shown to be important in the restoration of MG3 communities to semi-improved meadows (Smith et al., 2000, 2002). In the latter trial, farmyard manure (FYM) and small amounts of inorganic fertilizers had similar effects on vegetation, but these

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effects were small compared to those resulting from variations in timing of grazing and hay cutting. A combination of hay cutting and grazing is also the most common management of MG5 habitats, although a few are managed by extensive grazing only (Rodwell, 1992). Use of FYM and occasional liming are traditional practices in hay meadow communities, particularly MG3 and MG5 (Smith, 1988; Rodwell, 1992; Simpson & Jefferson, 1996; Tallowin, 1998; Crofts & Jefferson, 1999). Applications of FYM appear to encourage the development of soil fungal populations, in particular of vesicular-arbuscular micorrhizae (VAM) (Bardgett, 1996), whereas inorganic fertilizers reduce fungal populations in favour of soil bacteria (Sparling & Tinker, 1978; Bardgett et al., 1997). VAM play a role in the promotion of seedling establishment and the maintenance of species diversity in grasslands (Grime et al., 1987; van der Heijden et al., 1998). There have been many studies showing the detrimental effects of inorganic fertilizers on the botanical composition of species-rich meadows, for example the Park Grass Experiment (Lawes & Gilbert, 1859; Lawes, Gilbert & Masters, 1882; Brenchley & Warrington, 1958; Williams, 1978) and a study on the Somerset peat moors (Mountford, Lakhani & Kirkham, 1993; Kirkham, Mountford & Wilkins, 1996; Mountford, Lakhani & Holland, 1996). The Park Grass Experiment in particular provides valuable information on the long-term effects of fertilizer application, although the results were complicated to some extent because treatments were applied either as ammonium sulphate, which has an acidifying effect, or as sodium nitrate which does not (Williams, 1978). Furthermore, aftermath grazing was discontinued after 1877 to be replaced by a second cut, casting some doubt on the applicability of subsequent results to situations where traditional grazing management is maintained. Heavy periodic applications of FYM were made to one of the plots during the early years of the Park Grass Experiment. The effect of this treatment on the vegetation was similar to that of moderate annual rates of inorganic nitrogen (N), phosphorus (P) and potassium (K), namely an increase in grasses at the expense both of legumes and of herbs. However, no study appears to have been carried out where FYM treatments have been matched with inorganic fertilizers supplying equivalent amounts of these macro-nutrients, either to compare the effects on soil microbial populations or on plant communities. Recent reviews have concluded that more information is required, both on optimum rates and periodicity of FYM application and on the effects of lime and its interaction with FYM (Simpson & Jefferson, 1996; Tallowin, 1998). There is concern that, although existing guidelines (Simpson & Jefferson, 1996; Crofts & Jefferson, 1999) may represent sustainable practice for a wide range of meadows, these prescriptions may not be sustainable for some particularly species-rich communities. Moreover, changes in farming practice are already resulting in reduced availability of FYM. There is therefore a need to ascertain for certain if and/or when inorganic fertilisers might be sustainable alternatives, or whether commercially-available pelleted organic fertilizer might, in turn, be preferable to equivalent inorganic fertilizer. These questions need to be resolved in order to refine guidelines for the management of semi-natural and semi-improved grasslands within statutory sites and meadows managed under the Environmental Stewardship Scheme, with the overall objective of meeting BAP targets for Lowland Meadows and Upland Hay Meadows. Experimental plots were therefore established in 1999 in paired unimproved and semi-improved meadows in Cumbria, in south Wales and in Fermanagh, Northern Ireland. A wide range of FYM, inorganic fertilizer and lime treatments were applied over a period of

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six years at each site and the effects on botanical composition, yield and chemical composition of hay, soil chemistry and soil microbial indicators were monitored. This paper describes the response to these treatments of the plant communities in terms of species-richness and variables describing the ecological characteristics of the communities. A second paper describes analyses of these effects using a modelling approach based on ordination to investigate changes in vegetation in relation to simulated NVC communities (R.A. Sanderson, unpublished data). Agronomic results will be reported elsewhere (Tallowin et al., in preparation)

Methods

EXPERIMENT SITES

Experimental plots were established at six sites in the UK, two each in Cumbria, Northern Ireland (Fermanagh) and Wales (Monmouthshire). Cumbrian sites were located about 1.5 km apart in the Tebay-Orton area at 54º 27’ N and 2º 34’ W. Those in N. Ireland were located near Belleek at 54º 32’ N and 8º 3’ W and those in Wales were close to Monmouth at 51º 46’ N and 2º 41’W.

Past management

Each pair of sites consisted of species-rich (unimproved) meadow and one which had previously undergone some agricultural improvement (semi-improved). All sites had previously been managed over a long period by late cutting for hay (or occasionally for silage at semi-improved sites), typically in mid-July. Previous fertiliser management differed between sites (see Table 1). Table 1. Past fertilizer and lime inputs to unimproved (UI) and semi-improved (SI) experiment sites in Cumbria (Raisbeck and Gaisgill), Northern Ireland (Fassagh1 and Fassagh2) and Wales (Pentwyn and Bush).

Previous fertilizer management

Site FYMInorganic(kg element ha-1 year-1) Last limed

Raisbeck (UI) 12 ha-1 annually None c. 1993Gaisgill (SI) 37 t ha-1 every 2nd year 50 N, 11 P, 21 K c. 1989

Fassagh 1(UI) None since 1995 59 N, 11 P, 21 K since 1995 UnknownFassagh 2 (SI) None 59 N, 11 P, 21 K Unknown

Pentwyn (UI) None None UnknownBush (SI) None None Unknown

The unimproved site in Cumbria lies within the Raisbeck Meadows Site of Special Scientific Interest (SSSI), which has been managed for a number of years under an agreement with English Nature. The vegetation corresponds closely to the MG3b (Anthoxanthum odoratum-Geranium sylvaticum grassland, Briza media sub-community) community of the National Vegetation Classification (NVC) system (Rodwell, 1992). The site receives about 12 tonnes per hectare of farmyard manure (FYM) each year, usually in late April, but occasionally in mid summer following harvesting of hay. The site has also received periodic applications of lime, the last one in about 1993. The Gaisgill site (Cumbria, semi-improved) was taken into present

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ownership about 20 years before the experiments started, prior to which the field had received much lower nutrient inputs than at present (see Table 1), probably equivalent to those at Raisbeck. Inorganic fertilizers are applied in March-late April, whereas FYM is often applied in February-March or sometimes in the autumn. This site has not hitherto been subject to any environmental management agreement. The vegetation in 1999 corresponded to MG7 grassland, in particular the MG7e (Lolium perenne-Plantago lanceolata grassland) (Rodwell, 1992). The Northern Ireland (NI) sites (Fassagh 1 and 2) lie within the West Fermanagh and Erne Lakeland Environmentally Sensitive Area (ESA) and both fields have been subject to a management agreement under this scheme. At the site NI unimproved site (Fassagh 1), FYM was applied in unspecified amounts, without inorganic fertilizers, until 1995, after which FYM applications were replaced by inorganic fertilizers at the rate then being applied to Fassagh 2 (Table 1). These inputs of inorganic fertilizer have been maintained at both sites since then. No fertilizer or lime has been applied at the Welsh unimproved site (Pentwyn) since 1991 nor at the semi-improved site (Bush) since 1994, before which modest rates of inorganic fertilizer were applied at Bush (probably up to 50 kg N, 5 kg P and 10 kg K ha-1 year-1, although exact amounts are not recorded). Little is known of past fertilizer use at Pentwyn, and it is thought that none has been used since at least the mid 1980s. Anecdotal evidence suggests that basic slag may have been applied to Pentwyn at some time before that, and it is likely that both Pentwyn and Bush will have received lime in the past. The vegetation at Pentwyn in 1999 corresponded most closely to the MG5c (Cynosurus cristatus-Centaurea nigra grassland, Danthonia decumbens sub-community) whilst that at Bush was closer to MG5b (Galium verum sub-community) and MG6b and c (Lolium perenne-cynosurus cristatus grassland, Anthoxanthum odoratum and Trisetum flavescens sub-communities respectively) (Rodwell, 1992). At Fassagh 1 the vegetation was weighted towards MG5 communities, but less conclusively than at Pentwyn, whilst that at Fassagh 2 corresponded most closely to MG7d and e (Lolium perenne-Alopecurus pratensis and Lolium perenne-Plantago lanceolata grasslands respectively) (Rodwell, 1992). At all sites, regrowth is grazed after removal of the hay crop. At Cumbrian sites mature sheep are used, whereas the Welsh sites have been grazed sometimes sometimes by sheep and sometimes by cattle. In N. Ireland, sites are normally grazed by suckler cows and calves, and both these an the Welsh sites are grazed from 3-4 weeks after hay harvesting until the end of October-early November. Grazing normally commences in September-October at Cumbrian sites and continues until March or late April, sometimes until the first week in May at Raisbeck. At all sites normal grazing management, combined with hay cutting after the second week in July, has been maintained on experimental plots at all sites, with plots grazed along with the remainder of the field in each case.

EXPERIMENTAL DESIGN AND TREATMENTS APPLIED

All experimental treatments (see Table 2), were applied by hand to individual 7m x 5m plots laid out in a randomised block design with three replicate blocks at each site. The position of each block corner was fixed by a combination of measured coordinates to fixed field boundary features and buried metal markers relocated using a metal detector. In 1999, treatments were applied during the first week of May at Cumbrian sites and at the end of April at other sites, but thereafter treatments were applied in late March-early April at Welsh sites and in late April in Cumbria and N.

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Ireland. At all sites, treatments consisted of FYM (Treatments 3-8), inorganic equivalents to these (Treatments 9-12), lime only (Tr 13), lime plus annual FYM application (Tr 14), or lime plus intermittent FYM (Tr 15). In addition, a proprietary pelleted organic fertilizer (Humber-Palmer-Sheppey) was also tested at both Welsh sites and at the semi-improved site in Cumbria (Gaisgill). This was applied at the commercially recommended rate of 125 kg ha-1 of product (Treatment 16) or at twice this rate (Treatment 18). Inorganic equivalent to these treatments were also applied (Treatments 17 and 19 respectively), calculated from chemical analyses of the pelleted material.

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Table 2. Treatments applied sites in Cumbria, N.Ireland and Wales. Values shown are the mean amounts (kg ha -1 year-1) of N, P and K applied either as FYM (estimated) or in inorganic form (actual), averaged over six years 1999-2004. Note that all treatments were omitted in 2001, so that means shown for annual treatments represent 5/6 of the designated amounts. Treatments 16-19 were applied only at sites in Wales and at the semi-improved (SI) site in Cumbria. Note that treatment 2 at the unimproved (UI) site in Cumbria was identical to treatment 4. Intermittent treatments were applied in 1999 and 2002. Treatments included in the Form x Rate x Frequency (FRF) or Lime x FYM frequency (LFF) factorial series are indicated by ‘+’ in the relevant column.

Series Cumbria N. Ireland WalesTr no. Treatment FRF LFF N P K N P K N P K

1 Nil input control + 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.02 Continuation of past inputs (UI) 7.5 6.8 57.2 49.2 9.2 17.5 0.0 0.0 0.0“ “ “ “ (SI) 55.5 21.8 123.3 49.2 9.2 17.5 0.0 0.0 0.0

3 FYM at 6 t ha-1 annual 3.8 3.4 28.6 2.3 2.4 7.6 3.1 4.1 31.54 FYM at 12 t ha-1 annual + + 7.5 6.8 57.2 4.6 4.9 15.2 6.2 8.2 63.05 FYM at 24 t ha-1 annual + 15.0 13.6 114.4 9.2 9.7 30.4 12.0 16.4 126.16 FYM at 6 t ha-1 intermittent 1.5 1.4 11.5 1.0 1.0 2.8 1.5 1.8 13.77 FYM at 12 t ha-1 intermittent + + 3.0 2.7 22.9 1.9 2.0 5.5 3.1 3.5 27.38 FYM at 24 t ha-1 intermittent + 6.0 5.5 45.8 4.0 3.9 11.1 6.2 7.0 54.79 Inorganic equivalent to Tr 4 + 7.5 6.8 57.2 4.6 4.9 15.2 6.2 8.2 63.010 Inorganic equivalent to Tr 5 + 15.0 13.6 114.4 9.2 9.7 30.4 12.0 16.4 126.111 Inorganic equivalent to Tr 7 + 3.0 2.7 22.9 1.9 2.0 5.5 3.1 3.5 27.312 Inorganic equivalent to Tr 8 + 6.0 5.5 45.8 4.0 3.9 11.1 6.2 7.0 54.713 Lime applied in year 1 + 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.014 As Tr 13 + FYM as Tr 4 + 7.5 6.8 57.2 4.6 4.9 15.2 6.2 8.2 63.015 As Tr 13 + FYM as Tr 7 + 3.0 2.7 22.9 1.9 2.0 5.5 3.1 3.5 27.316 Organic pellets at 125 kg ha-1 12.8 2.9 6.5 n.a. n.a. n.a. 12.8 2.9 6.517 Inorganic equivalent to Tr 16 12.8 2.9 6.5 n.a. n.a. n.a. 12.8 2.9 6.518 Organic pellets at 250 kg ha-1 25.5 5.8 13.1 n.a. n.a. n.a. 25.5 5.8 13.119 Inorganic equivalent to Tr 18 25.5 5.8 13.1 n.a. n.a. n.a. 25.5 5.8 13.1

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At each pair of sites, the FYM used was obtained from the same local source each year and was sampled before or at application and analysed chemically as soon as possible afterwards. The ADAS Manure Nitrogen Evaluation Routine (MANNER; Chambers et al., 1999) was used to predict the amount of plant available N supplied by the FYM. P and K supply was calculated on the assumption that 60% and 90% of the total P and K content of the FYM respectively was plant-available (Anon, 2000; Groves, Chambers & Williams, 1999). Inorganic nitrogen (N), phosphorus (P) and potassium (K) were applied as ammonium, triple super-phosphate and muriate of potash respectively to the relevant treatments (see Table 2), with the amounts calculated individually to provide equivalent amounts to those supplied in FYM treatments. In 1999, 2000 and 2002, inorganic equivalent treatments were applied at the time of FYM spreading, with amounts based upon analyses of FYM carried out about 10 days beforehand. FYM was sampled and analysed again at spreading and differences in N, P and K content between initial analysis and the as-spread material were accounted for by adjustments made to the amounts of inorganic fertiliser applied at the next application. In 2003 and 2004, analyses were carried out sufficiently promptly for inorganic treatments to be applied within a few days after FYM application, with amounts calculated from analyses of as-spread material only. Lime was applied to plots of treatments 13, 14 and 15 at each site in amounts estimated to be sufficient to raise soil pH to 6.0, calculated on the basis of soil pH sampled in March-April 1999 and soil texture (Anon, 2000). Soil pH was checked again on these plots in March and October 2000. At Raisbeck and Gaisgill, 2 and 4 tonnes ha-1 respectively of lime were applied in single instalments in September 1999, whilst at Pentwyn and Bush, totals of 9.4 and 6.8 t ha-1 were applied in two instalments, in September 1999 and March 2000. Totals of 7.0 and 6.8 t ha-1 at Fassagh 1 and Fassagh 2 were applied in September 1999. At each site, one plot per replicate block received no fertilizer or lime (Treatment 1, nil input control) whilst plots designated as Treatment 2 received inputs representing a continuation of the past inputs described in Table 1. At the Cumbrian unimproved site (Raisbeck), the application to Treatment 2 plots corresponded exactly with Treatment 4, i.e. 12 tonnes FYM ha-1 each year. At the Welsh sites (Pentwyn and Bush), no fertiliser or lime had been applied previously, so that Treatments 1 and 2 were identical at these sites. At other sites, amounts of FYM and/or inorganic fertilizer corresponding with those shown in Table 1 were applied to Treatment 2 plots. It was not possible to apply treatments to any of the sites in 2001, due to restrictions resulting from the national outbreak of Foot and Mouth Disease (FMD). This resulted in a break in the continuity of annual treatment applications, which therefore received a total of 5/6 (83.3%) of the intended amounts over the six year period 1999-2004. Plots receiving 12 t ha-1 of FYM every year except 2001, for example, therefore actually received an average of 10 t ha-1 over the six years. Intermittent treatments were not due for application in 2001 and were therefore unaffected. Values for the mean amounts of N, P and K applied per year shown in Table 2 are therefore the aggregate amounts applied between 1999 and 2004 divided by six. At Gaisgill, the application of 37 t ha-1 of FYM due in 2001 on Treatment 2 plots (‘Continuation of past inputs’) was postponed until 2002. In view of the heavy amount involved, the next application was also delayed by a year and applied in 2004. The mean amounts of N, P and K applied to the Gaisgill Treatment 2 plots, averaged over the six years (see Table 2) were therefore made up of 41.7, 9.2 and 17.5 kg ha-1 year-1 respectively as inorganic fertilizer and 18.5, 13.9 and 105.8 kg ha-1 year-1 respectively in the form of FYM.

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BOTANICAL ASSESSMENTS

Botanical assessments were carried out at each site during May each year, except in 2001 when, due to FMD restrictions, only Welsh sites could be assessed. Assessments were carried out in three fixed 1m2 quadrat positions per plot, chosen randomly from all 12 possible positions within a 6m x 2m central area within each plot. The original position of each quadrat was relocated as accurately as possible each year by reference to measurements made down the centre of each plot. At each assessment, the percentage ground cover of each plant species present within each quadrat was recorded, including bryophytes and lichens, as well as cover of litter, bare ground, dung and FYM. At Cumbrian and N. Ireland sites, bryophytes were recorded to individual species level, but in Wales they were recorded only as ‘bryophytes’. All plots within a particular block were assessed by the same surveyor in a particular year, and consistency of scoring between different assessors at each site was checked at regular intervals by all surveyors working together on a number of quadrats. As far as possible the same surveyors were used each year; although some turnover of staff was inevitable, at least one surveyor was present in all six years at each site, with most of the remainder present in at least three consecutive years.

DERIVED VARIABLES

Species percent cover values were converted to a percentage of the total live vegetation cover present in each quadrat (which typically exceeded 120% cover), in order to minimise the effects of variation between years and between treatments in vegetation density and total cover. The data were used to calculate several composite variables, described below, which were then averaged across the three quadrats in each plot to give plot mean values for each variable. Plot means were used as the basic units for subsequent analyses of treatment effects.

Species-richness (species per m2)

Two species-richness variables were calculated for each site: the total number of vascular plant species per quadrat (1m2), and the number of positive mesotrophic indicator species per quadrat. The latter were taken from lists produced by Robertson & Jefferson (2000) for use in monitoring the condition grassland SSSIs in MG3 (Anthoxanthum odoratum-Geranium sylvaticum grassland) and MG5 (Cynosurus cristatus-Centaurea nigra grassland) communities of the National Vegetation Classification (NVC, Rodwell, 1992). These two communities were considered to be the most relevant community types for the unimproved sites in Cumbria and Monmouthshire, based upon their location and soil characteristics (Rodwell, 1992). These types are therefore suitable target communities for the corresponding semi-improved meadows. MG3 and MG5 positive indicator species are listed in Table 3.

Table 3. Positive indicator species for MG3 and MG5 National Vegetation plant communities (after Robertson & Jefferson, 2000).

NVC CommunityMG3 MG5 MG5 (contd)

Alchemilla glabra Agrimonia eupatoria Polygala sppAlchemilla spp Alchemilla glabra Potentilla erecta

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NVC CommunityMG3 MG5 MG5 (contd)

Anemone nemorosa Alchemilla spp Poygala vulgarisCentaurea nigra Anemone nemorosa Primula verisCirsium heterophyllum Carex flacca Rhinanthus minorConopodium majus Carex nigra Sanguisorba minorEuphrasia officionalis agg. Carex panicea Sanguisorba officinalisEuphrasia spp. Centaurea nigra Serratula tinctoriaFilipendula ulmaria Euphrasia officionalis agg. Silaum silausGeranium sylvaticum Euphrasia spp. Stachys officinalisGeum rivale Filipendula ulmaria Succisa pratensisLathyrus pratensis Filipendula vulgaris Tragopogon pratensisLeontodon autumnalis Galium verumLeontodon hispidus Genista tinctoriaLeontodon spp. Lathyrus linifoliusLotus corniculatus Lathyrus pratensisPersicaria bistorta Leontodon hispidusRhinanthus minor Leontodon saxatilisSanguisorba officinalis Leucanthemum vulgareSuccisa pratensis Lotus corniculatusTrollius europaeus Pimpinella saxifraga

The NVC surveys did not include Northern Ireland, so that target NVC community types are less easy to identify for the NI sites. However, ordination modelling of 1999 data suggested that the vegetation at the NI unimproved site (Fassagh 1) was also weighted towards MG5, though less closely affiliated with this community type than the vegetation at Pentwyn (Kirkham et al., 2002). The number of MG3 indicators and the number of MG5 indicators per m2 were calculated for each plot at each site.

Positive indicator species as a proportion of live vegetation cover

This variable was the total cover of positive indicator species as a proportion of total live vegetation cover. As with numbers per m-2, separate variables were calculated for MG3 and MG5 indicators for each site.

Proportion of ‘family’ groups

These variables were the proportions of live cover accounted for by grasses, herbs (forbs), legumes, bryophytes, rushes and the remainder. At Cumbrian and Welsh sites, the ‘rushes’ group was composed entirely of Luzula campestris, but several Juncus species were also present at the N. Ireland sites.

British Ellenberg Indices, N and R

Ellenberg N (nutrient level) and R (soil reaction or pH) indices were calculated from ecological indicator values for individual plants produced by Hill et al. (1999). These values were based upon original values derived from extensive survey data from mainland Europe (Ellenberg, 1988), modified for British conditions. Both N and R are based upon a nine point scale. Species with an N value of 1 are associated with very

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nutrient-poor conditions and those scoring 9 with extremely rich conditions; scores of 7-8 indicate rich to very rich habitats, while values of 3-5 indicate poor to moderate fertility. Examples of species recorded in this study with high N indices are Rumex obtusifolius (index 9), Urtica dioica (index 8), Heracleum sphondyllium (index 7), Lolium perenne, Poa trivialis, Dactylus glomerata, Trifolium repens and Cirsium arvense (index 6). Species with low-moderate N scores included Luzula campestris, Juncus acutiflorus, Carex nigra, Lotus corniculatus (all index 2), Anthoxanthum odoratum, Euphrasia officinalis, Leontodon hispidus, Ophioglossum vulgatum, Dactylorhiza fuchsia and Hypochaeris radicata (all index 3). Species associated with very acid conditions will have an R index of 1 and those associated with very basic conditions score 9; an index of 7 indicates neutrality and 5-6 indicate weakly acid conditions. Species recorded here fell within the range index 3 (e.g. Agrostis canina, Potentilla eracta, Carex echinata) to index 7 (e.g. Leontodon hispidus, Avenula pubescens, Primula veris, Trisetum flavescens, Ranunculus bulbosus, Leucanthemum vulgare, Bromus hordeaceus, Platanthera chlorantha D. fuchsia and Orchis morio). Two sets of composite scores were calculated for these indices, the first set on the basis of species presence alone (i.e. averaged over all species present) and the second set weighted to take account of the relative contribution to total live vegetation cover of each of the constituent species.

C, S and R radius scores

These scores were based upon the three primary plant strategies (competitor, stress-tolerator and ruderal) proposed by Grime (1977) and used information from a database compiled by Hodgson et al. (1995). Competitive (C) species are adapted to productive environments and/or those where disturbance and destruction of plant biomass is low, they generally have high relative growth rates and form large canopy structures. Stress-tolerators (S) are adapted to unproductive environments where there is a shortage of resources (e.g. low nutrient or moisture status, or low light levels) and are typically slow-growing and long-lived. Ruderal (R) species are characteristic of relatively productive environments with a high level of disturbance, resulting in destruction of plant biomass and the creation of bare ground. Each species has been allocated a radius score between 1 and 5 for each these three characteristics representing it position on a triangular C-S-R ordination. Examples of species recorded in 2004 that have a high C score are Cirsium arvense and U. dioica (score 5), D. glomerata, Filipendula ulmaria, Alopecurus pratense and Vicia cracca (all score 4). Species with a high S score included L. hispidus, Listera ovata, P. veris, Succisa pratensis, Polygala vulgaris (all score 5), Conopodium majus, Centaurea nigra, Luzula campestris, and Lotus corniculatus (all score 4). Those with a high R score included Bromus hordeaceus (score 5), Cardamine pratensis, Cerastium fontanum, Taraxacum officinale, Bellis perennis, Veronica serpyllifolia, Leontodon autumnalis, Rhinanthus minor and Crepis capillaris (all score 4).

DATA ANALYSIS

Data from 2004 for the above variables were tested for treatment effects by analysis of variance (ANOVA) and analysis of covariance (ANCOVA), the latter using 1999 data as the covariate (Genstat 5 Committee, 1997). For Ellenberg indices and C, S and R radius scores, only weighted values were analysed. Where an ANCOVA showed significant treatment covariance with 1999 data, the adjusted results were used. Data were analysed separately for each site, using three separate ANOVA models in each

11

case. In each model, variation between replicate blocks was accounted for by treating replicate as a blocking factor. The first model included all the treatments applied, with only Treatment and Block as the factors analysed. The other two models used balanced factorial subsets (series) of treatments (see Table 2): the Form x Rate x Frequency (FRF) series and the Lime x FYM frequency (LFF) series. The FRF series tested the effects form of fertilizer (i.e. FYM or inorganic), the rate at which fertilizers were applied (i.e. 12 or 24 t ha-1 FYM and inorganic treatments equivalent to these), the frequency at which treatments were applied (i.e. annual or intermittent), and all two- and three-way interactions between these factors. The LFF series tested the effects of lime (i.e. +lime versus –lime), the frequency of FYM application (i.e. nil, annual or intermittent) and the Lime x FYM frequency interaction. All FYM treatments within this series were applied at 12 t ha-1. Data for all years 1999-2004 (excluding 2001, except for the Welsh sites) were analysed together by the same models expanded to include Year as a repeated measures factor. Whilst these analyses included the overall effect of treatments (i.e. averaged over all years), the primary interest was in the interaction between treatment and Year to highlight temporal trends in response to individual treatments. Degrees of freedom for Year and interactions with Year were adjusted to account for departure from homogeneity of the population covariance matrix, using ε-coefficients calculated by the Greenhouse-Geisser method (Genstat V Committee, 1997). In order to satisfy the conditions for ANOVA, all percentage data were transformed before analysis by arcsine(√p), where p is the percentage value expressed as a proportion.

Results

DIFFERENCES BETWEEN SITES

Table 4 shows 1999 and 2004 overall means for each composite variable (non-transformed) at each site and the individual species recorded in 1999 and 2004 at each site are listed in the Appendix, along with the overall frequency (% of quadrats) and mean % ground cover of each. Data were not analysed statistically for differences between sites, but differences in composite variables are evident. Semi-improved sites (Gaisgill, Fassagh 2 and Bush) were, as expected, less species-rich than their unimproved counterparts, both in terms of the total number of species per m2 and, particularly, in terms of the number and contribution to live vegetation cover of positive indicator species. The Cumbrian unimproved site (Raisbeck) was notably more species-rich than other sites, although there was little difference in the number of positive indicator species per m2 between this site and the unimproved site in Wales (Pentwyn). The list of positive indicator species for MG5 grassland is longer than that for MG3 (see Table 3) but species common to both lists made up the bulk of the vegetation cover of positive indicator species at Pentwyn, e.g. Centaurea nigra, Leontodon hispidus, Rhinanthus minor and Lotus corniculatus (see Appendix). Of these species, C. nigra was by far the most abundant at Pentwyn, being recorded in all quadrats in both 1999 and 2004, occupying 20-22 % ground cover overall. At Raisbeck, Conopodium majus and L. hispidus were the most abundant positive indicator species. The unimproved site in N. Ireland (Fassagh 1) was less species-rich than those in Cumbria and Wales, with MG5 positive indicator species less abundant. Carex nigra was the most abundant of these in 1999, although this species had declined by 2004. Filipendula ulmaria was fairly common, with species such as

12

Carex panacea, C. flacca, Potentilla erecta and Lathyrus pratensis present at lower abundance (Appendix). The proportion of grass species in vegetation cover was consistently higher at unimproved sites than at semi-improved sites and was especially high at Gaisgill in 1999. These differences were mirrored by corresponding differences in herb cover at Cumbrian and Welsh sites, but by differences in the abundance of rushes (mainly Juncus acutiflorus and J. effusus) at N. Ireland sites. Herb cover was lower at Fassagh 1 than at Fassagh 2, with the latter largely composed of Ranunculus repens and, to a lesser extent, R. acris, Rumex acetosa and Bellis perennis (see Appendix). Legumes (mainly Trifolium pratense, T. repens and L. corniculatus) were fairly abundant at both Welsh sites in both years and at N. Ireland sites in 1999 (mainly T. pratense and T. repens), but were less abundant at Cumbrian sites. Bryophytes were much more abundant at sites in N. Ireland (where they mainly consisted of Rhytidiadelphus squarrosus) than elsewhere, and sedges were only present in any abundance at Fassagh 1 (mainly C. nigra), although even here they had declined significantly by 2004. Ellenberg N values were indicative of ‘moderately poor’ to ‘moderate’ fertility across all sites, but tended to be higher at semi-improved sites than unimproved sites in each region. These differences were generally more marked for weighted than unweighted values (Table 4). In both cases, the difference between semi-improved and unimproved sites was less marked in Wales than other regions, with values slightly lower overall at the sites in this region compared to others. Unweighted Ellenberg R indices were marginally higher at unimproved sites in Cumbria and Wales than other sites. In general, values indicate slightly acid conditions at all sites. Mean C and R radius scores were consistently higher at semi-improved sites than at unimproved sites within each region, whereas the opposite was true for S radius scores.

OVERALL CHANGES WITH TIME

Most variables showed an overall effect of Year in repeated measures analyses although these effects were sometimes attributable only to year-to-year fluctuations. Thus a difference between 1999 and 2004 means in Table 4 does not always indicate a consistent trend of increase or decline. Those cases where such a trend is judged to have occurred are noted by a + or – against Year in Table 5. Total species-richness showed no overall temporal trend at Raisbeck or Fassagh 2, but increased at Gaisgill and declined at both Fassagh 1 and Bush. However, both the number and relative cover abundance of positive indicator species increased at both Raisbeck and Bush, but declined at Fassagh 1. Too few of these species were present at Gaisgill or Fassagh 2 to determine temporal trends or treatment effects. The contribution of grasses and of legumes to vegetation cover declined markedly at Raisbeck in favour of herb species. These trends were largely attributable to net declines in Holcus lanatus, Agrostis canina, Trifolium repens and T. pratense and increases in Ranunculus acris and Leontodon hispidus. Conopodium majus and Centaurea nigra also increased, though these species were less abundant overall (Appendix). By contrast, both grasses and legumes increased at Fassagh 1 with concomitant declines in both herbs and rushes. The species that increased were mainly Anthoxanthum odoratum, Holcus lanatus, Trifolium repens and T. pratense, and to a lesser extent Cynosurus cristatus and Agrostis canina. Grasses also increased at the Welsh unimproved site (Pentwyn), largely attributable to a near doubling in ground

13

cover of Festuca rubra, with a corresponding decline in herb cover (mainly L. hispidus, Rhinanthus minor and Hypochaeris radicata). Legumes showed no consistent overall trend at this site, and neither grasses, herbs nor legumes showed any discernible overall trend at Bush. Grasses declined at both the remaining semi-improved sites (Gaisgill and Fassagh 2). At Gaisgill the decline was attributable to several species, mainly Poa trivialis, Alopecurus pratensis, and Lolium perenne, whereas at Fassagh 2 there was a large decline in cover of Agrostis stolonifera, from 49% in 1999 to 4% in 2004 (Appendix). This decline was largely in favour of legumes, particularly T. repens which increased from less than 1% cover in 1999 to about 17% in 2004. Cover of rushes also increased (mainly Juncus acutiflorus and J. effusus). Both herbs and legumes increased at Gaisgill, with the former largely attributable to an overall increase in Ranunculus acris. Changes in non-weighted Ellenberg indices were small compared to changes in weighted values. Both N and R indices declined at Raisbeck and Fassagh 2, but both increased at Pentwyn (Tables 4 and 5). There was no trend in Ellenberg N index at either Fassagh 1 or Bush, but Ellenberg R declined at Fassagh 1 and increased at Bush. Temporal trends in C, S and R radius scores differed between all sites. At Raisbeck, both C and R radius scores declined overall whereas S radius scores increased, whilst Pentwyn showed the opposite trends. At Fassagh 1, all three scores increased over time, presumably as a result of a decline in the proportion of cover occupied by species for which there was no C-S-R information. At Gaisgill C radius scores declined, R scores increased and S scores showed no overall trend, while at Fassagh 2 S scores increased, R scores declined and C scores showed no overall trend. At the Welsh semi-improved site (Bush), C scores declined but neither S nor R scores showed a discernible overall trend.

14

Table 4. Overall mean values of composite variables at six sites in 1999 and 2004. Unweighted Ellenberg indices and C, S and R radius scores are based upon species presence only, whereas weighted values take into account the relative abundance of the constituent species. ‘Trace’ indicates mean cover value of <0.05%.Variable Raisbeck Gaisgill Fassagh 1 Fassagh 2 Pentwyn Bush

1999 2004 1999 2004 1999 2004 1999 2004 1999 2004 1999 2004

Species m -2 All species 26.0 25.7 13.0 15.2 18.1 16.2 14.1 14.9 21.7 20.2 17.5 14.9MG3 positive indicators 5.0 6.4 0.1 0.2 0.8 0.5 0.3 0.2 4.8 4.4 0.8 1.5MG5 positive indicators 4.5 5.7 0.1 0.2 2.0 1.2 0.4 0.3 5.3 5.2 0.6 1.5

% of live coverMG3 positive indicators 14.7 33.1 Trace 0.2 4.4 1.7 0.7 0.3 35.1 22.5 3.2 7.5MG5 positive indicators 7.0 14.3 0.0 0.1 8.9 2.4 0.8 0.3 35.7 23.4 3.1 7.5Grasses 49.3 35.9 85.1 63.0 24.7 36.7 67.9 46.2 44.5 50.7 68.9 69.3Herbs 38.8 57.6 13.4 29.8 16.8 12.1 22.4 21.7 40.6 33.2 17.9 16.1Legumes 10.1 5.6 1.2 5.0 8.9 19.1 1.4 18.0 13.0 11.8 10.5 11.6Rushes 0.7 0.5 0.0 0.0 25.9 19.0 6.5 12.2 0.8 1.3 2.4 2.4Sedges 0.0 0.0 0.0 0.0 5.9 0.7 0.3 Trace 0.0 0.0 0.0 0.0Bryophytes 1.1 0.4 0.3 2.3 17.8 12.0 1.4 1.8 1.0 3.0 0.2 0.6Others 0.0 Trace 0.0 0.0 0.1 0.4 0.0 Trace Trace Trace 0.0 Trace

British Ellenberg scores - unweighted Br. Ellenberg N 4.43 4.42 5.04 5.09 4.23 4.13 5.03 4.76 4.08 4.14 4.51 4.44Br. Ellenberg R 5.99 6.01 5.61 5.71 5.45 5.22 5.75 5.68 5.99 6.00 5.86 5.82

British Ellenberg scores - weighted Br. Ellenberg N 4.47 4.38 5.04 4.64 3.99 4.09 5.57 4.87 4.00 4.42 4.29 4.39Br. Ellenberg R 5.79 5.75 5.48 5.50 5.42 5.07 6.25 5.69 5.71 5.83 5.38 5.54

C-S-R radius scores - unweighted C radius 2.42 2.39 2.68 2.70 2.73 2.85 2.86 2.77 2.46 2.47 2.74 2.66S radius 2.87 2.86 2.26 2.28 2.88 2.80 2.33 2.42 2.96 2.97 2.66 2.72R radius 2.88 2.88 3.20 3.19 2.60 2.59 2.94 2.92 2.83 2.75 2.94 2.90

C-S-R radius scores - weighted C radius 2.69 2.47 2.95 2.78 2.56 2.90 2.93 2.91 2.30 2.51 2.73 2.66S radius 3.05 3.26 2.61 2.71 2.48 2.74 1.71 2.43 3.27 3.18 2.90 2.90R radius 2.80 2.62 2.99 3.04 2.29 2.56 2.90 2.78 2.65 2.76 2.93 2.95

15

Table 5. ANOVA statistics for treatment factors in 2004 data, adjusted for covariance with 1999 data where appropriate (indicated by text and numbers in italics), for changes over time (Year) and for interactions with Year. Degrees of freedom (d.f.) for Year and x Year interactions are adjusted by Greenhouse-Geisser coefficients (ε) (see text). Symbols in parentheses indicate the trend over time (- decline, + increase, no value indicates that there was no discernible overall trend). Statistics for Ellenberg N and R indices and for C, S and R radius scores refer to analyses of weighted values. Only values for significant effects are shown: * P<0.05; ** P<0.01; *** P<0.001. Actual values are given for (near-significant) probability levels between P=0.05 and P<1.00 in 2004 analyses. Analysis

All treatments Form(Fo) x Rate(R) x Frequency(Fr) Lime (L) x FYM frequency (FYMf)

Site and variable FactorF-

ratio P d.f. FactorF-


ratio P d.f.

RaisbeckSpecies m-2 Treatments 1.91 0.072 13, 29 R 5.30 * 1, 14

Year 4.47 ** 3.2, 99.4 Fr 3.76 0.073 1, 14

MG3 ind. spp. m-2 Year (+) 72.8 *** 3.1, 95.4 Fr 3.70 0.075 1, 14 Year (+) 25.0 *** 2.4, 28.3Year (+) 36.6 *** 2.9, 47.1

MG3 ind. spp. % Treatments 2.23 * 13, 28 Fr 7.64 * 1, 14 FYMf 5.15 * 2, 10Year (+) 169.5 *** 3.1, 94.6 Year (+) 77.7 *** 2.6, 46.0

Grass% Treatments 2.40 * 13, 44 Fr 12.0 ** 1, 14 FYMf 3.57 0.068 2, 10Year (-) 27.0 2.5, 78.6 Year (-) 12.4 *** 2.3, 36.1 Year (-) 13.7 *** 2.1, 25.4

Herb% Treatments 2.32 * 13, 29 Fr 13.8 ** 1, 14 FYMf 4.01 0.053 2, 10Year (+) 89.5 *** 2.3, 71.6 Year (+) 46.3 *** 2.3, 37.2 Year (+) 37.6 *** 1.6, 18.6

Legumes% Year (-) 84.7 *** 3.2, 98.2 Fo 4.06 0.063 1, 14 L 3.37 0.096 1, 10R x Fr 6.82 * 1, 14 Year (-) 39.6 *** 2.4, 29.1Year (-) 47.4 *** 2.6, 42.0

Bryophytes% Treatments 3.26 ** 13, 29 Fr 6.01 * 1, 14 FYMf 7.72 ** 2, 10Year (-) 33.6 *** 2.6, 80.2 Fo x Fr 8.28 * 1, 14 L 8.14 * 1, 10

Year (-) 20.6 *** 2.4, 37.7 Year (-) 12.6 *** 2.3, 28.1

Rushes% Treatments 3.02 *** 13, 29 R 13.2 ** 1, 14 Year 6.72 ** 2.6, 31.5 (L. campestris) Year 14.5 *** 3.1, 94.8 Fo x Fr 3.15 0.098 1, 14

Year (-) 6.52 *** 3.1, 49.9

16

AnalysisAll treatments Form(Fo) x Rate(R) x Frequency(Fr) Lime (L) x FYM frequency (FYMf)




ratio P d.f.

Ellenberg N Year (-) 14.9 *** 2.6, 82.1 R 5.25 * 1, 14 Year (-) 9.85 *** 2.8, 33.8Year (-) 5.92 *** 2.7, 42.9R x Year 2.88 * 2.7, 42.9

Ellenberg R Treatments 2.77 * 13, 29 Fo x R 9.58 ** 1, 14 FYMf 5.96 * 2, 10Year (-) 3.64 * 2.8, 86.4 Year (-) 4.88 ** 3.0, 48.3 L 7.92 * 1, 10

C radius Treatments 2.41 * 13, 29 R 7.36 * 1, 14 Year (-) 29.1 *** 1.8, 21.4Year (-) 95.4 *** 2.5, 76.9 Fr 7.36 * 1, 14

Year (-) 60.3 *** 3.0, 47.4Fo x Year 3.04 * 3.0, 47.4R x Year 5.22 ** 3.0, 47.4Fr x Year 5.98 ** 3.0, 47.4

S radius Treatments 3.72 ** 13, 29 R 5.60 * 1, 14 FYMf 5.52 * 2, 10Year (+) 68.4 *** 2.3, 71.8 Fr 5.60 * 1, 15 Year (+) 24.6 *** 1.6, 19.0Treatment x Year 1.97 * 30.1, 71.8 Year (+) 29.4 *** 2.4, 37.6

Fr x Year 4.37 * 2.4, 37.6

R radius Treatments 2.59 * 13, 29 Fr 3.19 0.096 1, 14 FYMf 5.62 * 2, 10Year (-) 59.5 *** 2.4, 75.3 Year (-) 25.0 *** 2.3, 36.5 Year (-) 21.5 *** 1.6, 19.2Treatment x Year 1.50 * 31.6, 75.3

GaisgillSpecies m-2 Treatments 0.97 0.080 18, 35 Fo x Fr 4.51 0.052 1, 14 Year (+) 26.0 *** 2.6, 31.1

Year (+) 98.1 *** 3.1, 118.6 Year (+) 43.8 *** 3.1, 49.6

Grass% Year (-) 200.6 *** 2.6, 99.9 Fo x R x Fr 7.51 * 1, 13 L 6.03 * 1, 10Year (-) 85.9 *** 3.1, 48.8 Year (-) 82.4 *** 2.7, 32.3

Herb% Treatments 2.09 * 18, 36 Fo x Fr 5.74 * 1, 14 L 7.43 * 1, 10Year (+) 175.6 *** 2.9, 108.4 Year (+) 70.3 *** 2.9, 46.8 L x 9.38 ** 2, 10

17





ratio P d.f.FYMfYear (+) 59.8 *** 3.3, 39.6

Legumes% Year (+) 10.4 *** 1.6, 19.1

Bryophytes% Treatments 2.45 * 17, 34 Fo 9.47 ** 1, 14 FYMf 17.6 *** 2, 9Year (+) 79.8 *** 3.2, 120.3 R 3.98 0.066 1, 14 L 10.1 * 1, 9

Fr 19.1 *** 1, 14 Year (+) 17.9 *** 2.0, 24.6Year (+) 38.1 *** 3.3, 52.4Fr x Year 4.02 * 3.3, 52.4

Ellenberg N Treatments 3.67 *** 18, 35 Fo 7.39 * 1, 13 L 9.68 * 1, 10Year 46.7 *** 3.3, 125.7 R 12.6 ** 1, 13 Year 15.1 *** 3.2, 38.6Treat. x Year 1.47 * 59.5, 125.7 Year 27.7 *** 2.6, 41.3

Ellenberg R Treatments 2.72 * 18, 35 R 3.92 0.069 1, 13 L 7.27 * 1, 10Year 7.05 *** 2.9, 109.1 Fo x R 4.15 0.062 1, 13

Year 4.49 * 2.1, 34.3

C radius Treatments 2.87 ** 18, 36 Year (-) 29.3 *** 2.5, 40.7 Year (-) 25.1 *** 3.2, 38.1Year (-) 65.6 *** 3.3, 123.8

S radius Treatments 3.31 *** 18, 36 R 13.0 ** 1, 14 L 14.9 ** 1, 10Year 52.7 3.1, 119.5 Year 23.5 *** 2.9, 46.6 Year 24.5 *** 2.3, 27.5

L x Year 3.5 * 2.3, 27.5

R radius Treatments 1.98 * 18, 35 Year (+) 13.6 *** 2.5, 40.6 L 4.88 0.054 2, 9Year (+) 30.4 *** 2.9, 109.9 FYMf 3.07 0.096 2, 9

Year (+) 18.4 *** 2.6, 30.8

Fassagh1Species m-2 Year (-) 13.5 *** 3.4, 101.2 Fr 10.27 ** 1, 14 Year (-) 8.07 *** 2.8, 33.6

R x Fr 5.99 * 1, 14

18





ratio P d.f.Year (-) 8.46 *** 2.5, 40.4

MG5 ind. spp. m-2 Year (-) 29.2 *** 2.5, 76.2 Year (-) 18.2 *** 2.4, 39.0 Year (-) 7.74 * 1.8, 21.5

MG5 ind. spp. % Year (-) 39.4 *** 3.1, 92.9 Year (-) 19.8 *** 3.0, 47.8 Year (-) 22.1 *** 1.7, 19.9

Grass% Treatments 2.90 ** 14, 28 Fo x Fr 6.76 * 1, 14 FYMf 7.78 ** 2, 10Year (+) 40.2 *** 3.4, 103.6 Year (+) 22.2 *** 3.2, 51.9 Year (+) 17.0 *** 2.9, 35

Herb% Year (-) 9.70 *** 2.7, 80.9 Year (-) 5.64 ** 2.5, 40.5 L 6.44 * 1, 10

Legumes% Year (+) 39.0 *** 3.0, 91.2 Year (+) 14.2 *** 2.2, 35.1 Year (+) 24.9 *** 2.6, 31.6

Bryophytes% Treatments 2.21 * 14, 27 Fo 4.28 0.057 1, 14 FYMf 4.01 0.057 2, 9Year 13.8 *** 3.2, 97.4 R 5.54 * 1, 14 Year 7.49 ** 2.3, 27.2

Fo x Fr 9.11 ** 1, 14Year 11.1 *** 2.8, 44.5Fo x Fr x Year 3.07 * 2.8, 44.5

Rushes% Year (-) 12.7 *** 2.6, 76.5 R x Fr 3.35 0.088 1, 14 FYMf 6.75 * 2, 10Year (-) 7.53 ** 2.1, 33.0 Year (-) 5.39 * 1.9, 23.2

Ellenberg N Year 14.4 *** 2.9, 88.2 Fo x Fr 3.72 0.074 1, 14 L 6.64 * 1, 9Year 8.73 *** 2.5, 39.2 FYMf 4.04 0.056 1, 9

Year 7.71 *** 2.8, 33.4

Ellenberg R Year (-) 59.8 *** 3.2, 94.8 Fo 3.47 0.083 1, 14 L 4.12 0.073 1, 9Fo x Fr 4.29 0.057 1, 14 Year 37.5 *** 3.1, 37.8Year (-) 28.4 *** 3.0, 47.7 L x Year 3.57 * 3.1, 37.8

C radius Year (+) 44.1 *** 1.5, 44.3 R x Fr 4.12 0.062 1, 14 L 3.65 0.085 1, 10Year (+) 24.7 *** 1.4, 22.1 L x

FYMf 4.25 * 2, 10

19





ratio P d.f.Year (+) 23.4 *** 1.2, 14.4

S radius Year (+) 21.2 *** 2.0, 59.8 Year (+) 8.85 ** 1.7, 27.9 Year (+) 8.97 ** 2.0, 24.6

R radius Treatments 2.22 * 14, 28 Fo 3.80 0.071 1, 14 FYMf 17.9 *** 2, 10Year (+) 15.2 *** 2.4, 72.7 Fo x Fr 5.55 * 1, 14 Year (+) 10.5 *** 2.2, 26.0

Fo x R 3.26 0.092 1, 14Year (+) 9.02 *** 2.0, 32.2

Fassagh2Species m-2 Year 11.1 *** 3.1, 92.9 Year (+) 8.11 *** 2.8, 45.3 Year 4.20 * 3.2, 38.1

Grass% Treatments 2.03 0.054 14, 28 R 5.64 * 1, 14 FYMf 4.82 * 2, 10Year (-) 31.0 *** 3.0, 91.4 Fo x R 13.1 ** 1, 14 L x

FYMf3.27 0.081 2, 10

Fo x Fr 7.02 * 1, 14 Year (-) 12.6 *** 2.3, 27.4R x Fr 7.04 * 1, 14Year (-) 19.8 *** 2.7, 43.0

Herb% Year 4.05 ** 3.3, 98.1 Year 3.17 * 3.3, 52.0 L x FYMf

3.78 0.060 2, 10

Legumes% Year (+) 61.8 *** 2.4, 73.5 R 4.55 0.051 1, 14 FYMf 3.85 0.057 2, 10Year (+) 30.8 *** 2.1, 33.0 Year (+) 36.3 *** 2.8, 33.6

Bryophytes% Year 11.2 *** 3.1, 91.5 Year 5.43 ** 2.4, 39.2 Year 3.06 * 2.8, 33.2

Rushes% Year (+) 3.75 * 2.0, 59.0

Ellenberg N Year (-) 11.9 *** 1.9, 58.1 Year (-) 6.45 ** 1.9, 30.4 Year (-) 5.35 * 1.7, 20.2

Ellenberg R Year (-) 37.0 *** 2.0, 60.7 Fo x Fr 3.68 0.076 1, 14 Year (-) 12.9 ** 1.5, 18.3Year (-) 20.6 *** 2.4, 38.5

20





ratio P d.f.C radius Year 9.62 *** 2.9, 87.7 Year 3.69 * 3.1, 49.4 Year 4.15 * 1.8, 21.6

S radius Year (+) 48.8 *** 2.8, 84.8 Year (+) 22.7 *** 2.6, 40.9 Year (+) 19.8 *** 2.7, 32.4

R radius Year (-) 7.7 *** 4.0, 156 Year (-) 5.47 ** 2.1, 33.7

PentwynSpecies m-2 Year 9.31 *** 3.3, 127.4

MG5 ind. spp. m-2 Year 7.81 *** 4.0, 156.0 Fo 6.42 * 1, 14Fr 7.69 * 1, 14Year (-) 4.22 ** 3.3, 53.4Fr x Year 4.00 * 3.3, 53.4

MG5 ind. spp. % Year (-) 22.6 *** 3.8, 149.5 Year (-) 9.62 *** 3.5, 55.4 Year (-) 9.75 *** 3.6, 43.7

Grass% Year (+) 9.37 *** 3.8, 147.5 Year (+) 3.16 * 3.5, 55.3 Year (+) 3.02 * 2.8, 33.2

Herb% Year (-) 12.1 *** 3.9, 151.1 Year (-) 5.66 ** 3.5, 56.7 L 3.74 0.082 1, 10Year (-) 3.24 * 2.8, 34.1

Legumes% Treatments 2.46 * 17, 37 Fo 3.45 0.084 1, 14 FYMf 7.43 * 2, 10Year 8.63 *** 3.9, 150.3 R x Fr 8.34 * 1, 14 Year 6.51 *** 3.6, 43.7

Year 3.20 * 3.3, 52.1R x Fr x Year

3.65 * 3.3, 52.1

Bryophytes% Year (+) 15.3 *** 3.0, 115.6 Fo 16.8 *** 1, 14 FYMf 3.55 0.068 2, 10Fr 15.6 *** 1, 14Year (+) 5.29 ** 3.2, 51.5Fr x Year 3.30 * 3.2, 51.5

Rushes% Treatments 1.73 0.081 17, 35 Fr 3.22 0.094 1, 14 Year 4.10 ** 3.6, 42.7 (L. campestris) Year 11.1 *** 4.2, 163.4 Fo x Fr 3.22 0.095 1, 14

21





ratio P d.f.Treat. x Year 1.34 * 71.2, 163.4 Fo x R x Fr 7.50 * 1, 14

Year 6.72 *** 3.5, 55.8Fo x R x Fr x Year

3.38 * 3.5, 55.8

Ellenberg N Year (+) 66.4 *** 3.8, 150.1 Year (+) 35.0 *** 3.0, 47.5 Year (+) 42.1 *** 4.1, 48.7

Ellenberg R Year (+) 15.1 *** 3.3, 129.4 R 3.64 0.077 1, 14 Year (+) 5.80 ** 2.7, 32.9Year (+) 6.92 ** 2.3, 37.5

C radius Year (+) 30.8 *** 3.4, 133.3 Year (+) 15.2 *** 2.6, 41.5 Year (+) 16.2 *** 2.7, 32.8

S radius Treatments 2.20 * 17, 36 Year (-) 6.31 ** 3.1, 48.9 L 4.01 0.078 1, 10Year (-) 11.10 *** 3.8, 149.2 Fo x R x Fr

x Year3.21 * 3.1, 48.9 FYMf 3.18 0.085 2, 10

Year (-) 6.34 ** 3.1, 36.8

R radius Year (+) 11.7 *** 4.0, 156.1 Year (+) 7.03 *** 3.7, 58.7 L 4.78 0.054 1, 10Year (+) 5.24 ** 3.8, 45.5

BushSpecies m-2 Treatments 1.93 * 17, 36 Fr 8.29 * L 3.42 0.094 1, 10

Year (-) 31.2 *** 4.4, 169.9 Year (-) 9.47 *** 3.4, 54.1 Year (-) 10.4 *** 2.8, 33.2Treat. x Year 1.49 * 74.1, 169.9 Fr x Year 3.12 * 3.4, 54.1

MG5 ind. spp. m-2 Year (+) 43.9 *** 3.1, 120.0 Year (+) 21.3 *** 2.7, 43.2 Year (+) 19.6 *** 2.8, 33.8

MG5 ind. spp. % Year (+) 20.1 *** 3.6, 140.9 Year (+) 10.5 *** 3.9, 62.4 Year (+) 10.9 *** 2.5, 30.1Fr x Year 3.79 * 3.9, 62.4

Grass% Year 32.5 *** 3.8, 149.8 Year 20.8 *** 3.8, 61.2 Year 11.6 *** 2.6, 31.5

Herb% Year 31.4 *** 3.5, 137.4 Fo 4.66 * 1, 14 Year 12.2 *** 2.5, 30.4Year 18.2 *** 3.4, 55.2

22





ratio P d.f.

Legumes% Treatments 1.85 0.058 17, 37 R x Fr 8.67 * 1, 14 FYMf 3.74 0.066 2, 9Year 41.9 *** 3.5, 137.7 Year 19.0 *** 3.4, 54.1 L 2.65 0.092 2, 9Treat. x Year 1.43 * 60.0, 137.7 Year 21.4 *** 3.5, 41.9

L x Year 7.36 *** 3.5, 41.9

Bryophytes% Year 3.83 * 3.1, 37.4

Rushes% Year 12.9 *** 3.7, 145.8 Fo 3.56 0.082 1, 13 Year 4.11 * 3.3, 39.4 (L. campestris)Ellenberg N Year 18.0 *** 3.5, 138.4 Year 7.29 *** 2.6, 42.3 Year (+) 10.7 *** 2.9, 34.5

Ellenberg R Treatments 3.56 *** 17, 37 Fo x R x Fr 11.1 ** 1, 14 Year (+) 23.4 *** 3.1, 36.8Year (+) 26.4 *** 3.8, 146.7 Year (+) 12.9 *** 2.9, 46.8

C radius Year (-) 26.3 *** 3.2, 125.5 Year (-) 10.8 *** 2.3, 37.5 Year (-) 7.45 ** 2.6, 31.4

S radius Year 5.41 *** 3.9, 150.9 Year 2.97 * 3.0, 48.3 Year 3.03 ** 2.9, 34.3

R radius Year 3.03 * 3.2, 125.4

23

Table 6. The effects of fertilisers and/or lime on vegetation properties in 2004 at the unimproved site in Cumbria (Raisbeck), as characterised by 10 composite variables. Figures in parentheses are means back-transformed to % of live vegetation cover. See Table 2 for explanation of treatment numbers. Values shown for Treatment 4 are means of Treatments 2 and 4 (see Table 2). Significance of ANOVA treatment: NS, P>0.05; *, P<0.05, **, P<0.01. Error df = 29, except where adjusted for covariance with 1999 data (SEDs in italics) where df = 28.

Means of arcsine-square root transformed % of live cover Weighted scoresTreat-ment

Species m-2

MG3 positive indicator species Grasses Herbs Bryophytes

Ellenberg R C radius S radius R radius

1 26.0 0.68 (39.8) 0.59 (30.5) 0.93 (64.3) 0.083 (0.7) 5.82 2.33 3.48 2.43

3 26.6 0.60 (32.1) 0.61 (33.1) 0.89 (60.8) 0.069 (0.5) 5.80 2.46 3.27 2.604 24.5 0.58 (30.0) 0.68 (39.2) 0.84 (55.3) 0.025 (0.1) 5.68 2.52 3.19 2.685 22.1 0.45 (19.2) 0.77 (48.2) 0.78 (49.1) 0.036 (0.1) 5.76 2.67 2.91 2.836 26.4 0.71 (42.2) 0.61 (32.6) 0.89 (60.3) 0.053 (0.3) 5.75 2.46 3.33 2.587 27.7 0.64 (35.2) 0.63 (34.3) 0.88 (59.0) 0.081 (0.7) 5.67 2.43 3.33 2.568 26.2 0.59 (31.3) 0.65 (36.7) 0.85 (56.5) 0.058 (0.3) 5.79 2.47 3.26 2.62

9 26.8 0.61 (32.8) 0.67 (38.3) 0.81 (52.6) 0.061 (0.4) 5.74 2.44 3.32 2.60

10 25.0 0.56 (27.9) 0.75 (46.4) 0.75 (46.8) 0.045 (0.2) 5.68 2.57 3.18 2.7011 26.1 0.64 (36.0) 0.59 (30.5) 0.92 (63.0) 0.055 (0.3) 5.79 2.38 3.30 2.6312 26.3 0.67 (38.3) 0.58 (30.3) 0.91 (62.2) 0.045 (0.2) 5.68 2.47 3.28 2.63

13 27.4 0.70 (41.8) 0.51 (23.8) 0.97 (68.0) 0.044 (0.2) 5.92 2.30 3.50 2.4314 23.9 0.50 (23.0) 0.70 (41.6) 0.79 (50.7) 0.007 (<0.1) 5.75 2.55 3.14 2.7315 26.6 0.62 (33.9) 0.60 (31.9) 0.89 (60.7) 0.041 (0.2) 5.82 2.48 3.21 2.64

SEDs:Tr. 4 v others 1.35 0.061 0.056 0.051 0.0147 0.054 0.077 0.190 0.082Others 1.56 0.071 0.064 0.059 0.0170 0.063 0.089 0.108 0.095

NS * * * ** * * ** *

24

THE INFLUENCE OF FERTILIZER AND LIME TREATMENTS

Significant treatment effects detected in 2004 data, significant year effects and any significant treatment x year interactions are summarised in Table 5. The summaries include the results both of analyses of all treatments applied at each site and of factorial analyses within the Form x Rate x Frequency (FRF) and Lime x FYM frequency (LFF) factorial treatment series.

TREATMENT EFFECTS AT UNIMPROVED SITES

Effects on species-richness and the abundance of positive indicator species

Although there was no overall trend in species-richness (total number of species per m2) with time at Raisbeck, richness increased slightly with some treatments - notably nil input control, lime only and intermittent treatments - and declined in others. The latter included treatment 4 (12 t FYM ha-1, continuation of past inputs) and, more particularly, treatments 5 and 10 (24 t FYM ha-1 and the inorganic equivalent). Treatment effects on species-richness in 2004 was marginally non-significant when all treatments were included (P=0.072, Table 6), although the form x rate x frequency (FRF) subset analysis showed an overall effect of rate of application (P<0.05), with 26.7 and 24.9 species per m2 following medium and high rates of application respectively, averaged over the two forms of fertilizer. Note that ‘medium’ and ‘high’ rates refer to 12 and 24 t FYM ha-1 and their inorganic equivalents. Intermittent treatments also resulted in marginally higher species-richness than annual treatments (26.6 and 25.1 species m-2 respectively) though this difference was not quite significant (P=0.073). There was no significant treatment effect on the number of MG3 positive indicator species per m-2 at Raisbeck in 2004, although there was a marginally greater density of these species following intermittent treatments compared to annual treatments within the FRF series (P=0.075). As noted earlier, positive indicator species increased overall with time when expressed as a proportion of vegetation cover. However, this increase was negligible on plots receiving the high rate of FYM (24 t ha -1, treatment 5) than others, so that differences between this treatment and several others were significant in 2004 (Table 6). The latter included: treatment 4 (12 t FYM ha-1

annually), which represented a continuation of past inputs; treatment 10, the inorganic equivalent to treatment 5; and treatment 8, the intermittent FYM treatment at the high rate (all P<0.05). There was no significant overall effect of rate or form of fertilizer within the FRF subset, but MG3 positive indicators were more abundant following intermittent treatments compared to annual applications within this series (P<0.05). Cover of MG3 positive indicators was relatively high on nil input control plots (treatment 1) in 2004, at about 40% of live cover, with only plots receiving intermittent FYM at the low rate or lime alone (treatment 13) supporting equivalent levels. The latter plots contained a significantly higher (P<0.001) proportion of these species than those receiving both lime and annual FYM (treatment 14), but not compared to lime plus intermittent FYM (treatment 15). Averaged over +lime and -lime treatments within the lime x FYM frequency (LFF) series, positive indicator species occupied a lower proportion of live vegetation cover on annual FYM plots than on those receiving no FYM (P<0.01), but with intermittent FYM not differing

25

significantly from either. There was no overall effect of lime within the LFF series, nor any interaction with FYM. Both species-richness and particularly the proportion of MG3 indicators in vegetation cover show a linear response to rate of FYM applied annually at Raisbeck, decreasing with increasing application rate in the range 0-24 t FYM ha-1 (treatments 1-5). No such response to intermittent treatments is evident. There was no significant overall treatment effect at Fassagh 1 in 2004 on either species-richness (i.e. the overall number of species per m2) or on the number or proportional cover of MG5 positive indicator species, nor any effect on indicator species cover within either the FRF or LFF treatment series (Table 5). However, within the FRF treatment series, plots receiving intermittent treatments were significantly (P<0.01) more species-rich than those receiving annual fertilizer, averaged over both forms (16.8 species m-2 compared to 15.2), with lower species-richness following annual applications at the medium rate (14.6 species m-2) compared to intermittent applications at the same rate (17.3 species m -2, P<0.01) or at the high rate (16.2 species m-2, P<0.05). At Pentwyn, both species-richness and the proportionate cover of MG5 indicator species were apparently unaffected by treatments. However, the number of MG5 indicator species per m-2 in 2004 was influenced by both form and frequency of fertilizer application within the FRF series (FYM<inorganic and intermittent>annual, both P<0.05), with a significant (P<0.05) interaction between frequency of application and year. Whilst there was no significant change between years with intermittent application, the density of MG5 indicators had been reduced significantly by 2001 under annual application, averaged over FYM and inorganic treatments within this series (from 5.6 to 4.6 per m2, P<0.001), with no significant change thereafter. The number of MG5 indicator species did not change between 1999 and 2004 with nil input control (i.e. the treatment representing a continuation of past inputs at this site), but declined noticeably with all rates of annual fertiliser application, including the lowest FYM rate of 6 t ha-1. Thus, in terms of response to rate of FYM applied annually, the main difference in 2004 was between nil input control (5.7 species per m2) and 6 t FYM ha-1 (4.9 species per m2), with 4.8 and 4.4 species per m2 for 12 and 24 t FYM ha-1 respectively. Nevertheless, there was no overall treatment effect in 2004 data, so that these differences were not statistically significant.

Effects on the proportion of grasses, herbs, legumes, bryophytes and rushes

At Raisbeck, plots receiving lime only (treatment 13) contained the lowest proportion of grasses and the highest proportion of herbs in 2004, although intermittent treatments of inorganic fertilizers (treatments 11 and 12) and nil input contained similar levels (Table 6). There was no overall effect of lime on the proportion either of grasses or herbs within the LFF series. Plots of the high rate annual fertilizer application, both FYM and inorganic (treatments 5 and 10 respectively), were notably more ‘grassy’ and with less herb cover than other treatments, the comparisons reaching high levels of significance (P<0.001) for both these treatments compared to treatment 13, both for grasses and for herbs. Treatment 4 (12 t FYM ha-1 year-1, continuation of inputs) did not differ significantly in grass content compared to control, though these plots and their inorganic equivalents (treatment 9) contained a significantly higher proportion of grasses than lime-only plots (P<0.01) and with a lower herb content (P<0.05 for treatment 4, P<0.01 treatment 9). Within the FRF

26

series, intermittent treatments were significantly less ‘grassy’ with a greater herb content than annual treatments (both P<0.01). In terms of response to increasing application rate in the range 0-24 t FYM ha-1 (treatments 1-5), grass content decreased while herb content increased correspondingly. Both variables tend to show a non-linear rate response to intermittent treatment, due largely to differences between treated plots and nil input controls. At Fassagh 1, increases in grass content between 1999 and 2004 were particularly noticeable with annual fertilizer treatments, including treatment 2 (continuation of past inputs). Despite a small increase with time on plots of treatment 1 (untreated control), several treatments were significantly grassier by 2004 than the untreated control, namely: treatments 2 and 10 (both P<0.05) and treatments 4, 5, 14 and 15 (all P<0.01) (Table 7). No treatment significantly exceeded treatment 2 in grass content, but, in addition to treatment 1, treatments 3, 6 and 9 were all less ‘grassy’ than treatment 2 (P<0.01 for treatment 6, P<0.05 the remainder). Plots receiving lime only contained a significantly lower grass content than those of treatment 4, the most ‘grassy’ of the treatments (Table 7), but there was no overall effect of lime within the LFF series. FYM tended to produce vegetation with a higher grass content than inorganic equivalents (P=0.052), and there was a significant (P<0.05) Form x Frequency of application interaction in the FRF series, with annual FYM applications producing a significantly higher grass content than all other combinations (P<0.01 compared to intermittent FYM and annual inorganic treatments). Plots receiving annual FYM at 12 t ha-1 were also significantly ‘grassier’ than those receiving no FYM, averaged over +lime and –lime treatments in the LFF treatment series (P<0.01). Herb content at Fassagh 1 in 2004 showed few treatment effects, although herbs were significantly (P<0.05) reduced overall by lime addition within the LFF series (-lime = 14.4%, + lime = 9.4%, back-transformed means – all percentage values quoted hereafter are back-transformed from means of arcsine-square root transformed data unless stated otherwise). Table 7. The effects of fertilisers and/or lime on the proportion of grasses, herbs and bryophytes in vegetation cover in 2004 at the unimproved site in Northern Ireland (Fassagh 1). Figures in parentheses are means back-transformed to % of live vegetation cover. See Table 2 for explanation of treatment numbers. Significance of ANOVA treatment: NS, P>0.05; *, P<0.05, **, P<0.01. Error df = 28, except for bryophytes (SED in italics), for which data were adjusted for covariance with 1999 data, df = 27.

Means of arcsine-square root transformed % of live coverTreatment Grasses Herbs Bryophytes

1 0.57 (28.7) 0.42 (16.6) 0.426 (17.1)2 0.69 (40.5) 0.39 (14.7) 0.355 (12.1)

3 0.59 (31.2) 0.29 (8.3) 0.285 (7.9)4 0.75 (46.4) 0.39 (14.1) 0.207 (4.2)5 0.72 (43.8) 0.35 (11.6) 0.191 (3.6)6 0.57 (29.3) 0.29 (7.9) 0.448 (18.8)7 0.62 (33.9) 0.36 (12.5) 0.406 (15.6)8 0.65 (36.6) 0.37 (12.7) 0.295 (8.5)

9 0.59 (30.8) 0.36 (12.2) 0.451 (19.0)10 0.67 (38.6) 0.37 (12.8) 0.404 (15.5)11 0.64 (35.4) 0.35 (11.8) 0.376 (13.5)

27

12 0.66 (37.2) 0.39 (14.2) 0.277 (7.5)

13 0.63 (35.1) 0.36 (12.2) 0.385 (14.1)14 0.70 (41.1) 0.31 (9.3) 0.243 (5.8)15 0.69 (40.7) 0.27 (6.9) 0.267 (7.0)

SED 0.045 0.062 0.0837** NS *

At Pentwyn, the proportion of grasses increased slightly between 1999 and 2004 with most treatments, but declined slightly with nil input control and the lime only treatment. Herb content declined with all treatments. There was no significant influence of treatment on grass or herb content in 2004 and, although lime appeared to have maintained a higher proportion of herbs than other treatments within the LFF series, the difference was marginal and not significant (36.8% compared to 32.8%, P=0.082). Legumes were affected by treatments at both Raisbeck and Pentwyn, but not at Fassagh 1, despite a large overall increase in legume content between 1999 and 2004 at the latter site (see Table 4). At Raisbeck, the proportion of legumes declined between 1999 and 2004 under all treatments, including nil input control and treatment 4 (i.e. continuation of past inputs). Although the decline was noticeably smaller where lime had been applied compared to most other treatments, the resulting overall difference in 2004 due to lime was slight and non-significant (6.7% compared to 4.7%, P=0.096). Similarly, legumes appeared to decline less with inorganic treatments than with their FYM counterparts, so that there was a marginal overall difference by 2004 (6.3% compared to 4.7%, P=0.063). However, legume content in 2004 showed a significant interaction (P<0.05) between frequency and rate of fertilizer application within the FRF series, and a significant overall effect of year (P<0.001), when averaged over the two forms, but no significant interaction with year. The proportion of legumes in 2004 was lowest following annual fertilizer application at the high rate, i.e. 24 t FYM ha-1 and inorganic equivalent (P<0.05 compared to annual medium rate and intermittent high rate applications) (Figure 1a). Legumes showed a similar pattern in 2004 at Pentwyn, where there was also a significant interaction with year (Figure 1b). At this site, legumes fluctuated between years with the medium rate intermittent fertilizer application in particular (averaged over FYM and equivalent inorganic treatments within the FRF series) and were significantly (P<0.01) more abundant in 2000 with this treatment combination compared to others except high rate annual application. Legume content did not differ between treatments in 2001, 2002 or 2003, but by 2004 was lower following high rate annual application than other combinations (P<0.05 compared to high rate intermittent, P<0.01 compared to the remainder). Overall, legume content was highest in 2004 following the medium rate annual FYM treatment and its inorganic equivalent (treatments 4 and 9, 19% and 22% respectively) and the equivalent FYM treatment applied to limed plots (treatment 14, 17%). Both treatments 4 and 9 allowed a significantly higher (P<0.01) legume content in 2004 than the corresponding higher rates (treatments 5 and 10, 7% and 11% respectively) when all treatments were analysed, although there was no significant overall effect of rate of application within the FRF series. FYM treatments within the LFF series tended to confirm those within the FRF series with respect to differences between annual and intermittent treatments at the medium rate. Within the LFF series, annual FYM allowed a significantly higher (P<0.01) legume content (17.9%) than intermittent FYM (8.7%), with nil FYM treatments (12.8%) not significantly different from either annual or intermittent FYM

28

(all averaged over + and – lime). There was no overall effect of lime on legumes at this site, nor any lime x FYM interaction within the LFF series. In addition to these differences, analysis of 2004 legume data for all treatments together at Pentwyn showed significantly lower legume content for both treatments 17 (inorganic equivalent to the lower rate organic pellets) and 18 (higher rate organic pellets) compared to nil input control (i.e. 5.6% and 4.6% compared to 13.6%, P<0.05 and P<0.01 respectively), as well as a significant difference between the two rates of the organic pellets, treatment 16 and treatment 18 (11.8% compared to 4.6%, P<0.05). Organic pellet treatments did not differ significantly from their inorganic equivalents at either rate. The difference at the lower rate (11.8% compared to 5.6% for treatment 16 compared to treatment 17) was very nearly significant, but at the higher rate the difference was reversed and less pronounced (4.6% and 7.4% for treatments 18 and 19 respectively).

0.10

0.15

0.20

0.25

0.30

1

Frequency and rate of application

Arc

sin-

sqrt

( p o

f cov

er)

Medium MediumIntermittent Annual

High HighIntermittent Annual

Rate x Frequency *

a)

(8.7)

(6.1)

(4.0)

(2.2)

(1.0)

' 99 ' 00

' 01 ' 02

' 03 ' 04

Medium IntermittentMedium Annual

High IntermittentHigh Annual

0.0

0.1

0.2

0.3

0.4

0.5

Arc

sin-

sqrt

(p o

f co

ver)

YearRate-

frequency

Year x Rate xFrequency *

b)(23.0)

(15.2)

(8.7)

(4.0)

(1.0)

(0.0)

Figure 1. Effect on the contribution of legumes to live vegetation cover of rate and frequency of fertilizer application at Raisbeck in 2004 (a) and the interaction between rate, frequency and year at Pentwyn (b), all averaged over the two forms of fertilizer. Values plotted are means of arcsine-square root transformed data (proportion of live cover). Values in parentheses against the y- and z-axes are values back-transformed to percentages.

Bryophytes were sensitive to treatments at all three unimproved sites, particularly at Fassagh 1 where they were much more abundant than at other sites. Bryophyte cover showed no overall temporal trend at this site, although bryophytes tended to be less abundant in 2004 than 1999 with most treatments, with the notable exceptions of nil input controls, low and medium rate intermittent FYM treatments, the high rate intermittent inorganic treatment and treatment 10 (high rate annual inorganic treatment). Bryophyte content in 2004 did not differ significantly between treatment 2

29

(continuation of past inputs) and any other treatment, but was lower following annual FYM treatments than others, with treatments 4, 5 and 14 all significantly lower than nil input control (P<0.01 for treatment 5) (Table 7). Within the FRF series, the difference between FYM and inorganic means (7.2% of live cover compared to 12.5%) was marginally non-significant (P=0.052). The overall difference due to rate of application (medium>high) was significant, however (P<0.05), and there was a significantly higher bryophyte content on plots receiving annual inorganic fertilizer compared to annual FYM (P<0.01) or intermittent inorganic treatments (P<0.05). The latter differences developed largely between 2003 and 2004. Averaged over medium and high application rates, mean bryophyte content declined significantly following both intermittent and annual FYM application (P<0.05 and P<0.001 respectively) and intermittent inorganic treatments (P<0.01), but not following annual inorganic treatments (probability levels are derived from a Form x Rate x Frequency x Year ANOVA). There was no significant difference between these four treatment combinations in years earlier than 2004. At Raisbeck, bryophyte content fluctuated markedly from year to year under all treatments but was consistently lower in 2004 than in 1999 for all treatments except nil input control. In 2004, bryophytes were more abundant on nil input control plots than all others and were least abundant on plots of treatment 4 and 14 (the latter = lime plus annual FYM equivalent to treatment 4), the difference between control and both these treatments being highly significant (P<0.001)(Table 6). Bryophytes were significantly less abundant on treatment 4 plots compared to several other treatments, including the inorganic equivalent to treatment 4 (treatment 9), but not compared to treatments 5 and 10 (the higher rate of annual FYM and its inorganic equivalent). Intermittent FYM treatments tended to support higher bryophyte cover than annual treatments and plots receiving lime had low bryophyte cover, particularly those also receiving annual FYM (treatment 14). These effects, coupled with the low levels on treatment 4 plots, resulted in significantly lower mean bryophyte cover for annual FYM applications within the LFF series, compared to both nil and intermittent FYM (both P<0.01), and a significantly lower mean for limed plots compared to unlimed (P<0.05). At Pentwyn, bryophytes tended to decline between 1999 and 2000 under most treatments and increase progressively after that, so that bryophyte content was higher overall in 2004 than in 1999. This trend was not shown by all treatments, however, and differences between treatments in 2004 were broadly similar to those shown at the other sites. Bryophyte content was lower on FYM plots compared to inorganic (P<0.001), and higher following intermittent compared to annual treatments (P<0.001) (data not shown). The latter difference reflected a significant increase in bryophyte content between 2002 and 2004 under intermittent fertilizer application, following an initial decline between 1999 and 2001 (both effects P<0.05), but with no significant difference between years under annual fertilizer application, averaged over both forms of fertilizer (Year x Frequency effect P<0.05). Inorganic treatments equivalent to the HPS organic pellets appeared to result in greater bryophyte content than the organic pellets themselves, i.e. 9.0% compared to 3.7% at the lower rates (treatments 16 and 17) and 4.1% compared to 1.1% at the higher rates (treatments 18 and 19), calculated from non-transformed data. These values compare with a nil input control mean of 5.3%. However, data for these treatments were not analysed separately from the complete set, within which the overall treatment effect for bryophytes was marginally non-significant (P<0.056). A least significant difference

30

(LSD) calculated from this analysis suggested no significant difference between any of the above five treatments. At both Raisbeck and Pentwyn, Luzula campestris was the only representative of the rush family (Juncaceae), whereas Juncus acutiflorus, J. conglomeratus and J. effusus were also frequent at Fassagh 1 (Appendix). Though the habitat ranges of Luzula and Juncus species overlap, Luzula species are primarily associated with drier habitats compared to Juncus (Stace, 1997). The response of Luzula at the Cumbrian and Welsh sites should therefore be viewed as that of an individual species rather than as a representative of the Juncaceae group as a whole. At both sites, the response of L. campestris was somewhat similar to that of bryophytes. The species was relatively sparse at both sites in 2004, i.e. 1.0% on nil input control plots at Raisbeck and 1.4% at Pentwyn, when it tended to be more abundant on thesel plots than those receiving fertilizer, and less abundant with annual FYM treatments compared with either intermittent FYM or annual or intermittent inorganic treatments. Luzula was more abundant with medium rate applications compared to high rates within the FRF series at Raisbeck (P<0.01). At Pentwyn, it showed a significant (P<0.05) Form x Rate x Frequency interaction within the FRF series, with lowest abundance following annual applications of high rate FYM (0.5%) and highest levels with intermittent medium rate FYM (2.6%). At Fassagh 1, rushes declined progressively in abundance from an overall mean of 26% cover in 1999 to 19% in 2004, with the decline following this trend closely both on plots where past inputs were continued (treatment 2, 26% to 18%) and on nil input controls (29% to 20%). The decline was most marked with annual fertilizer applications, however, although there was no significant effect of form, rate or frequency of application within the FRF treatment series in 2004, and a marginally non-significant rate x frequency effect (P=0.088). There was no effect of lime within the LFF series, but annual FYM applications reduced the abundance of rushes in 2004 (13.5%) compared to both intermittent FYM (17.8%, P<0.05) and nil FYM inputs (20.4%, P<0.01) when averaged over + and – lime treatments within this series.

Effects on British Ellenberg N and R indices

Weighted British Ellenberg N indices (N scores) were influenced by treatments at Raisbeck and at Fassagh 1, but not at Pentwyn. At Raisbeck, N scores declined over time with most treatments, including both the nil input control and the continuation treatment (treatment 4), but not on plots of the high rate FYM treatment (treatment 5) or its inorganic equivalent (treatment 10). Only the lime alone treatment (treatment 13) produced a lower N score than control in 2004 (4.27 compared to 4.31). However, there was no significant overall effect of treatment, nor a year x treatment interaction, although N scores were significantly higher overall in 2004 for high rate treatments compared to medium rate within the FRF series (4.46 compared to 4.37, P<0.05). There was no overall difference between FYM and inorganic equivalents, and little evidence of a relationship with rate of application of FYM over all rates of either annual or intermittent application: only annual FYM application at the high rate gave scores notably higher than other FYM treatments. The same was true at Fassagh 1, but here FYM tended to produce higher Ellenberg N scores in 2004 than did inorganic equivalents, as did high rate treatments compared to medium rate, though neither effect was significant in the FRF treatment series. There was a near-significant Form x Frequency interaction in this series (P=0.074), with the highest mean N score resulting from annual FYM application (4.33) and the lowest following annual inorganic treatments (3.74); intermittent treatments differed

31

little between forms (4.19 FYM, 4.22 inorganic). Addition of lime significantly increased the N score (P<0.05), averaged over + and – FYM treatments in the LFF series (+lime = 4.12, -lime = 4.07), with a near significant (P=0.056) effect of FYM frequency within the same series (N scores = 3.96, 4.12 and 4.20 for nil, intermittent and annual FYM treatments averaged over + and – lime). Weighted British Ellenberg reaction indices (R scores) were influenced by lime treatments at Raisbeck and Fassagh 1 but not at Pentwyn. At Raisbeck, the highest mean Ellenberg R score in 2004 was that for the lime alone treatment, treatment 13 (Table 6). The R score for this treatment was significantly higher (P<0.05) than that for all other treatments except nil input control and treatments 3, 8 and 15, the difference being particularly marked compared to treatments 4, 6, 7, 9, 10 and 12 (P<0.01). The significant difference between treatment 13 and treatment 14 was notable, since the latter treatment had also received lime. Nevertheless, there was a significant overall difference (P<0.05) between + and – lime treatments within the LFF series (5.83 compared to 5.71), as well as significant differences for nil FYM (5.87) compared to intermittent FYM (5.74, P<0.05) and annual FYM (5.70, P<0.01), averaged over + and – lime. At Fassagh 1, the effects of lime appeared to be marginal, although there were significant differences in temporal trend between plots receiving lime compared to those without lime. R scores did not differ significantly between + and – lime treatments in any year in a lime x FYM frequency (LFF) x year analysis (Figure 2a). However, initial mean scores in 1999 (before lime application) were notably higher on plots not designated to receive lime compared to those to which lime was subsequently applied. By 2004 this difference had been reversed, and was nearly significant (P=0.073) in the analysis of 2004 data alone when adjusted for covariance with 1999 data. R scores declined overall between 1999 and 2000, with the decline highly significant for both –lime and +lime treatments (P<0.001), and then increased progressively between 2000 and 2004 on all plots (significantly so between 2003 and 2004, P<0.05). The mean R score for –lime treatments remained significantly lower in each year compared to 1999 (P<0.001), but by 2004 the mean R score for limed plots no longer differed significantly from the 1999 value for these plots.

4.5

4.7

4.9

5.1

5.3

5.5

1999 2000 2001 2002 2003 2004Year

Br.

Elle

nber

g R

- Lime + LimeLime x Year *

4.5

4.7

4.9

5.1

5.3

5.5

Intermittent AnnualFrequency of application

Br.

Elle

nber

g R

FYM Inorganic

Form x Frequency P=0.057a) b)

Figure 2. Effects on weighted British Ellenberg reaction (R) scores at Fassagh 1: (a) changes 1999-2004 as influenced by lime application; and (b) effects of form and frequency of fertilizer application on scores in 2004.

There was also a marginally non-significant (P=0.057) Form x Frequency of application effect within the FRF series, with notably lower Ellenberg R scores for annual inorganic treatments compared to others within the series (Figure 2b). This effect was noticeable at both rates of application.

32

Effects on C, S and R radius scores

At Raisbeck, weighted competitor (C radius) scores declined overall under most treatments, particularly nil input control and lime-only (treatment 13), but declined very little on plots of treatment 5 (high rate annual FYM) and treatments 4 and 14 (medium rate annual FYM, - and + lime respectively). The mean C radius score for treatment 5 in 2004 was significantly higher than for any other treatment except its inorganic counterpart (treatment 10) and treatments 4 and 14, with the difference reaching a high significance level (P<0.001) compared to nil input control and treatment 13. The rate of decline in C radius score was influenced by form, rate and frequency of fertilizer application (Table 5 and Figure 3a, b and c) Within the FRF treatment series, FYM treatments resulted in higher C radius scores than inorganic equivalents in each year after 1999, though the difference was significant (P<0.05) only in 2003 (Figure 3a). The decline was slower when the high rate was applied compared to the medium rate (Figure 3b) and where fertilizers were applied annually compared to intermittently (Figure 3c, so that differences due to both rate and frequency were significant (P<0.05) by 2004, but not in earlier years. Trends in stress-tolerator (S radius) score closely mirrored those in C radius, increasing particularly on nil input control plots and those that had received lime only (treatment 13). Scores declined with high rate annual FYM application (treatment 5) and changed little with either the inorganic equivalent to treatment 5 (treatment 10) or with annual applications at the medium rate, with or without lime (treatments 4 and 14), resulting in significant differences between these treatments and both the nil input control and treatment 13 in 2004 (P<0.001 for treatment 5 compared to both, P<0.01 for remainder except treatment 4 compared to control, P<0.05). Treatment 13 also differed significantly from treatments 8 and 15 (P<0.05). Within the FRF series, the overall increase in S radius score was influenced only by frequency of application (Table 5 and Figure 3d). There was no significant mean increase in S score after 2002 under annual fertilizer application, in contrast to intermittent application under which scores increased significantly between 2002 and 2004 (P<0.001). The difference between fertilizer frequencies (intermittent>annual) was significant (P<0.05) in 2004 but not in earlier years (Figure 3d), and not within the LFF series in 2004, when both annual and intermittent FYM resulted in lower mean S scores compared to nil FYM, averaged over + and – lime treatments (P<0.01 for nil compared to annual). There was no overall effect of form of fertilizer within the FRF series, but, despite the lack of a significant interaction between year and application rate, analyses of 2004 data alone showed higher S scores following medium rate application compared to the high rate (P<0.05).

33

2.3

2.4

2.5

2.6

2.7

2.8

1999 2000 2001 2002 2003 2004

Year

C-ra

dius

Inorganic FYM

Form x Year *

2.3

2.4

2.5

2.6

2.7

2.8

1999 2000 2001 2002 2003 2004

Year

C-ra

dius

Medium High

Rate x Year **

2.3

2.4

2.5

2.6

2.7

2.8

1999 2000 2001 2002 2003 2004Year

C-ra

dius

Intermittent Annualc)

Frequency x Year **

2.6

2.8

3.0

3.2

3.4

1999 2000 2001 2002 2003 2004Year

S-ra

dius

Intermittent Annuald) Frequency x Year *

a) b)

Figure 3. Changes in weighted competitor score (C radius: a, b and c) and stress tolerator score (S radius: d) at Raisbeck, as influenced by form (a) rate (b) and frequency (c and d) of fertilizer application.

Ruderal (R radius) scores at Raisbeck followed similar trends to those of C radius, declining overall and markedly so on nil input control plots and those of treatment 13 (both P<0.001 comparing 2004 with 1999). The decline was also significant (P<0.05) under treatment 4 (continuation of past inputs), but changed little under treatment 5 (from 2.80 to 2.83, N.S.) or the inorganic equivalent (treatment 10, 2.78 to 2.70, N.S.). Scores also declined very significantly (P<0.001) under the lowest rate FYM applied either annually or intermittently (treatments 3 and 6), under intermittent FYM treatment at the medium rate (treatments7) and under the inorganic equivalents to treatments 4, 7 and 8 (high rate intermittent application), although the decline was smaller under treatment 8 itself (P<0.05). Scores changed little where FYM was applied annually to plots that received lime in 1999 (i.e. treatment 14, 2.78 to 2.73, N.S.), but declined where FYM was applied intermittently to limed plots (treatment 15, 2.82 to 2.64, P<0.01). There was no resulting overall effect of lime in the analysis of 2004 data within the LFF series, but annual FYM application led to significantly higher R radius scores than nil FYM, averaged over + and - lime (P<0.01), though not than intermittent FYM. The mean score for treatment 5 was significantly higher than all others except its inorganic equivalent (treatment 10), treatment 4 and treatment 14, with the difference highly significant compared to nil input control and treatment 13 (P<0.001). There was no significant effect of form, rate or frequency within the FRF series, although the mean score for annual treatments were marginally higher than that for intermittent treatments within this series (2.70 compared to 2.61, P=0.096). Both C and R radius scores increased linearly with increasing rate of annual application of FYM over all treatments 1-5, whilst S radius scores decreased correspondingly. As with both herb and grass cover at this site, the responses of C, S and R radius scores to the same rates applied intermittently were less marked and non-linear, with the main difference being between nil input controls and the FYM treatments.

34

C radius scores increased with time under most treatments at Fassagh 1, including nil input control, treatment 2 (continuation of past inputs) and treatment 13. Analysis of 2004 data for C radius at this site showed no significant effect when all treatments were included, but C radius scores tended to be lower with lime application compared to treatments that excluded lime in the LFF series (P=0.085). This was largely due to a significantly lower C radius mean for lime plus intermittent FYM compared to treatments without lime (P<0.01 compared to intermittent FYM -lime) and compared to lime alone (Figure 4a). R radius scores also increased with time at this site, although, unlike Raisbeck, trends in relation to the treatments differed from those shown by C radius scores. Increases were particularly marked on plots receiving annual FYM at the medium and high rate (treatments 4, 5 and 14), and were least with low rate intermittent FYM (treatment 6) and the inorganic equivalent to treatment 4 (treatment 9). Differences between these two groups of treatments were significant in 2004 (P<0.001 for treatment 4 compared to both treatment 6 and 9, P<0.01 for other differences except for treatment 5 compared to treatment 6, P<0.05). The mean score for treatment 4 also differed significantly (P<0.05) from those for nil input control, treatment 2 and treatment 3 (annual FYM at the lowest rate). Within the FRF series, the mean R radius score for annual applications of inorganic fertilizer was significantly lower than for other treatments within this series (P<0.01 compared to annual FYM) (Figure 4b).

2.7

2.8

2.9

3.0

Nil Intermittent Annual

Frequency of FYM application

C-ra

dius

- Lime + Limea) Lime x FYM frequency *

2.2

2.3

2.4

2.5

2.6

2.7

2.8


R-ra

dius

FYM Inorganic Form x Frequency *b)

Figure 4. Interactions (a) between lime and FYM application and (b) between form and frequency of FYM on weighted C radius and R radius scores respectively at Fassagh 1.

S radius scores increased overall at Fassagh 1 between 1999 and 2004, with the main increase occurring between 1999 and 2000. However, there was no treatment x year interaction, nor any significant treatment effect in analyses of 2004 data alone. C radius scores tended to increase overall at Pentwyn but were not influenced by treatments, and R radius scores showed only a marginal difference due to lime application within the LFF series (2.81 compared to 2.73 for +lime and -lime respectively, P=0.054). S radius scores tended to increase slightly initially but then declined, particularly between 2003 and 2004, although the mean score for nil input controls (equivalent to continuation of past inputs) differed little between 1999 and 2004. Scores in 2004 were significantly influenced by treatments when all plots were included in the analysis, though only after adjustment for covariance with 1999 data (Figure 5). There was no consistent effect of rate of FYM application within this analysis: within the FYM treatments, S radius scores were lowest for the intermediate rate of FYM applied annually, significantly lower than for the higher rate applied annually (P<0.05), whereas scores were inversely related to increasing rate of FYM applied intermittently, albeit that these treatments did not differ significantly. The score for the high rate annual FYM application (treatment 5) was significantly higher

35

(P<0.01) than its inorganic equivalent (treatment 10), the latter being significantly lower than all other treatments except those receiving lime (treatments 13, 14 and 15). All the latter were significantly lower than nil input controls (P<0.01 for treatment 14) and than treatments 11 (P<0.01 for treatment 14), with the mean score for treatment 14 also significantly lower than treatments 6 (P<0.01) and treatments 12 and 17 (both P<0.05).

2.9

3

3.1

3.2

3.3

3.4

1,2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Treatment

S-r

adiu

s

Unadjusted Adjusted for covariance with 1999 data

LSD treatments 3-19LSD Treat. 1,2 vs. others

Figure 5. Effect of all treatments on the stress-tolerator (S radius) score at Pentwyn in 2004. Error bars represent least significant differences (LSDs) at P<0.05 for data adjusted for covariance with 1999 data.

There was no significant overall effect of lime on S radius score within the LFF series in 2004 and no overall effect of form, rate or frequency of FYM application within the FRF series, nor any interaction within this series in 2004 data, but there was a significant (P<0.05) four-way interaction between form, rate, frequency and year in the repeated measures ANOVA (Table 8). Overall mean scores tended to increase in 2001 and to decline again thereafter. The difference between 1999 and 2001 means was significant (P<0.05) for all treatments except the intermittent FYM and the annual inorganic treatments at the higher rate. Except for the increases in 2001, S radius scores remained relatively unchanged on plots receiving inorganic fertilizers at the medium rate applied either annually or intermittently, in contrast with other treatments. The initial mean score for annual inorganic applications at the high rate (treatment 10) was exceptionally high compared to other treatments and was, by chance, significantly (P<0.01) higher than the corresponding 1999 mean for annual FYM at the same rate (Table 8). This explains the marked effect of adjustment for covariance with 1999 data on the 2004 treatment 10 mean within the 2004 analysis of all treatments (Figure 5). The mean S radius score on these plots subsequently declined, significantly so by 2002 compared to its 1999 value (P<0.001), but increased significantly between 1999 and 2000 under the corresponding FYM treatment, remaining relatively constant thereafter. The latter effect contrasted with changes with time on plots receiving annual FYM at the lower (medium) rate, where scores declined between 1999 and 2000 and between 2001 and 2002 (both P<0.05) with a highly significant difference between 1999 and 2004 (P<0.001). The mean scores for the intermittent FYM treatment at the high rate also declined after 1999, but

36

not significantly so until 2004 compared to its 1999 value (P<0.05). The mean score for medium rate intermittent treatments changed little between 1999 and 2004.

Table 8. Interaction between form, rate, frequency of application and year on stress-tolerator (S radius) scores at Pentwyn. Asterisks indicate the significance of ANOVA effects: *, P<0.05; **, P<0.01).

Medium rate High rate Year

YearForm Intermittent Annual Intermitte

ntAnnual mean

s

1999FYM 3.22 3.38 3.32 3.19

3.27Inorganic 3.19 3.20 3.09 3.56

2000FYM 3.29 3.23 3.26 3.26

3.27Inorganic 3.21 3.21 3.34 3.38

2001FYM 3.36 3.30 3.29 3.30

3.33Inorganic 3.30 3.38 3.26 3.48

2002FYM 3.19 3.17 3.28 3.28

3.21Inorganic 3.19 3.18 3.22 3.21

2003FYM 3.27 3.19 3.19 3.27

3.21Inorganic 3.25 3.19 3.20 3.14

2004FYM 3.17 3.10 3.15 3.23

3.17Inorganic 3.28 3.13 3.20 3.10

SEDs:Between years (same form, rate and frequency) 0.065 (year means) 0.033Other comparisons 0.112

* **

TREATMENT EFFECTS AT SEMI-IMPROVED SITES

Effects on species-richness and the abundance of positive indicator species

Species-richness declined at Gaisgill between 1999 and 2000 (from an overall mean of 13.0 species per m2 to 11.0 species per m2) and increased thereafter with all treatments. The increases were greatest for nil input control (from 11.6 to 16.8 per m2) and with treatments 3 (11.3 to 16.5 per m2), 6 (12.0 to 16.0 per m2), and 10 (11.1 to 16.2 per m2). In 2004, nil input control plots were the most species-rich, whereas those of treatment 2 (continuation of previous inputs) were the least (12.6 species per m2). However, the treatment effect in the 2004 ANOVA for all treatments was marginally non-significant (P=0.083) and there was no significant year x treatment interaction. There was a near-significant Form x Frequency of application interaction in the FRF series for 2004 (P=0.052), with the lowest species-richness resulting from annual applications of FYM compared with annual inorganic treatments and intermittent treatments of both forms (i.e. 14.2 per m2 compared to 15.2-15.6 per m2). MG3 and MG5 positive indicator species were too sparse at Gaisgill and Fassagh 2 respectively to show significant treatment effects, and total species-richness was not affected at Fassagh 2. However, both overall species-richness and the proportion of MG5 positive indicator species in vegetation cover were influenced at Bush (see Table 5).

37

10

12

14

16

18

20

1,2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Treatment

Spe

cies

per

m2

Unadjusted Adjusted for covariance with 1999 data

LSD treatments 3-19

a)

LSD Treat. 1,2 vs. others

10

12

14

16

18

20

1999 2000 2001 2002 2003 2004Year

Spe

cies

per

m2

Intermittent Annualb) Frequency x Year *

Figure 6. Effect of treatments on species-richness at Bush: (a) all treatments in 2004; and (b) the effect of frequency of application on changes between 1999 and 2004. Error bars in (a) represent least significant differences (LSDs) at P<0.05 for data adjusted for covariance with 1999 data.

At Bush, there was a significant treatment x year interaction, and also a significant treatment effect on species-richness in 2004 data alone when all treatments were included and the analysis was adjusted for covariance with 1999 data (Figure 6a) (both effects P<0.05). There was also a significant frequency x year interaction in the FRF series (Figure 6b). Species-richness declined overall after 2000, averaged across all treatments (from 17.6 to 14.8 species per m2). The nil input control treatment showed little change until 2003-2004, however, when species-richness declined from 17.7 to 14.7 species per m2 (P<0.001). Treatments 6 and 7 declined progressively, whereas treatments 8, 11 and 14 showed little overall change, so that the latter were significantly more species-rich in 2004 than nil input control (Figure 6a). Treatments 10, 18 and 19 were the least species-rich in 2004, and though these treatments did not differ from nil input controls they were significantly less species-rich than treatments 8, 11, 13 and 14 (P<0.01 compared to treatments 8 and 11) (Figure 6a). There was no overall effect of form or rate of fertilizer in 2004 within the FRF series, but plots treated annually were significantly less species-rich than those treated intermittently (P<0.05). This difference reflected a significant decline in species-richness with annual treatments (P<0.05 by 2003 compared to 1999, P<0.01 by 2004) but only a slight (non-significant) trend with intermittent applications (Figure 6b). However, there was no consistent response to rate of FYM across all rates (i.e. including nil input controls and 6 t FYM ha-1) applied either annually or intermittently. Plots receiving lime increased in species-richness in general, particularly in conjunction with annual FYM (treatment 14), although the lime plus intermittent

38

FYM treatment changed little. Within the LFF series in 2004, limed plots tended to be more species-rich than un-limed ones, though not significantly so overall (P=0.094).

0.00

0.05

0.10

0.15

0.20

0.25

0.30

1999 2000 2001 2002 2003 2004

Year

Arcs

in-s

qrt c

over

Intermittent Annual

Frequency x Year *

(6.1)

(4.0)

(2.2)

(1.0)

(0.25)

(0.00)

(8.7)

Figure 7. Changes 1999-2004 in the proportion of positive indicators in live vegetation cover at Bush. Data shown are means of data transformed to arcsines of square roots of percentage values expressed as a proportion. Values in parentheses against the y-axis are values back-transformed to percentages.

There was no effect of treatment on the number of MG5 positive indicator species per m2 at Bush in 2004, although the number had increased in general over time. There was an apparent non-linear, negative response to all FYM rates applied annually, with only a slightly lower mean density of indicator species in 2004 following 6 t ha -1 year-

1 compared to nil input control (1.6 compared to 1.7 species m -2) and a linear decrease between 6 and 24 t ha-1 (to 0.8 species m -2). Corresponding intermittent treatments showed no such response, either in terms of the number of indicator species or in terms of the proportion of vegetation cover they occupied. There was, however, a significant (P<0.05) frequency of application x year interaction within the FRF series in the latter variable (Figure 7). There was no difference in any year attributable to application frequency, but the proportion increased significantly with both annual and intermittent application by 2002 compared to 1999 (P<0.05). There was no further increase under annual application, whereas the proportion increased significantly between 2003 and 2004 (P<0.001) with intermittent application. This effect was largely attributable to Rhinanthus minor, which had appeared in most plots by 2001 and increased sharply between 2003 and 2004 on plots receiving intermittent FYM treatment at the medium rate, from a mean of about 0.5% to 10.1%. Some new ingress of other MG5 positive indicators also occurred on these plots in 2004 (i.e. Tragopogon pratensis, Leontodon hispidus and Lathyrus pratensis) and on plots receiving intermittent inorganic treatments at the high rate (i.e. L. hispidus, Leucanthemum vulgare and Primula veris), but not at levels sufficient to contribute to the trends illustrated in Figure 7.

39

Effects on the proportion of grasses, herbs, legumes, bryophytes and rushes

The contributions of grasses to vegetation cover showed several significant treatment effects at Gaisgill and Fassagh 2 with herbs also responding significantly at Gaisgill. The only effect among these two groups at Bush was a significantly higher (P<0.05) mean proportion of herbs with FYM treatments compared to their inorganic equivalents within the FRF series (18.1% compared to 13.0%). At Gaisgill, the proportion of herbs was increased overall by lime application within the LFF series (+lime = 33.1%, -lime = 26.5%, P<0.05), mirrored by a corresponding difference in grass content (+lime = 58.4, -lime = 65.2, P<0.05). The increase in herbs was attributable to a highly significant (P<0.001) effect of lime when applied without FYM (Figure 8a). Conversely, where FYM was applied either annually or intermittently there was no significant effect of lime; and the herb content was significantly lower when lime was applied in conjunction with FYM than when applied without it (P<0.01 for both annual and intermittent FYM). There was no apparent rate response to FYM applied annually or intermittently, either across all treatments or within the FRF series. The herb content at Gaisgill was, however, influenced by form of fertilizer within the FRF series, though only significantly so when treatments were applied intermittently (FYM<inorganic, P<0.05) (Figure 8b). By contrast, herb content at Fassagh 2 in 2004 tended to be lower on limed plots compared to un-limed ones, though not significantly so. This difference was most noticeable on plots receiving annual FYM, though the lime x FYM frequency interaction was not quite significant (P=0.06).

0.3

0.4

0.5

0.6

0.7

0.8

Nil Intermittent Annual


Arc

sine

-sqr

t (p

of c

over

)

- Lime + Lime Lime x FYM frequency *(51.5)

(41.5)

(31.9)

(23.0)

(15.2)

(8.7) 0.3

0.4

0.5

0.6

0.7

0.8


FYM Inorganic Form x Frequency *b)a)


Figure 8. The contribution of herbs to vegetation cover at Gaisgill in 2004, as influenced by the interaction of lime and FYM application a) and by form and frequency of FYM b). Values in parentheses against the y-axis are values back-transformed to percentages.

The trends in herb content at Gaisgill described above can be attributed largely to the response of Ranunculus acris. This species had increased on most plots since 1999 and was the most common herb species present in 2004. However, trends differed on plots of treatment 2 (continuation of past inputs) where R. repens was the most common herb in 2004. These two species were approximately equal in abundance in 1999, each at about 3% of vegetation cover overall, and both were less abundant than Rumex acetosa (about 5%). However, whereas R. acris increased progressively on most plots to an overall mean of 15%, R. repens increased under treatment 2 (to 16% of vegetation cover) with little change in R. acris. Rumex acetosa showed little effect of treatment and differed little in abundance between 1999 and 2004, although it increased generally to about 10-15% in 2002, declining again thereafter.

40

As with herb content, the proportion of grasses at Gaisgill showed no apparent response in 2004 to rate of FYM across all FYM treatments applied either annually or intermittently. However, there was a significant (P<0.05) three-way interaction between form, rate and frequency of application in the FRF series (Figure 9a), though none of these factors alone nor any two way interaction was significant. Intermittent FYM at the high rate and annual inorganic equivalents at the lower (medium) rate produced comparable levels of grass content (56-58%), with these levels significantly lower than intermittent FYM at the lower rate or annual inorganic fertilizer at either rate (P<0.01 between rates of intermittent FYM, P<0.05 the remainder). These trends largely reflect corresponding differences in Holcus lanatus content. Poa trivialis was also more abundant with annual FYM treatments than others, particularly at the high rate, but levels were generally low compared to Holcus (means of 1-7% compared to 22-35% for H. lanatus). Anthoxanthum odoratum was the second most abundant grass (13-22%), but this species did not appear to be influenced by form, rate or frequency of fertilizer (note that individual species were not analysed separately).

41

IntermittentMedium Annual

IntermittentHigh Annual

FYM

Inorganic0.80

0.85

0.90

0.95

1.00

Arc

sine

-sqr

t (p

of c

over

)


(70.8)

(66.2)

(61.4)

(56.4)

(51.5)

a) Form x rate x frequency *

IntermittentMedium Annual

IntermittentHigh Annual

FYM

Inorganic0.6

0.7

0.8

0.9

1.0

Arc

sine

-sqr

t (p

of c

over

)


(70.8)

(61.4)

(51.5)

(41.5)

(31.9)

b)

Form x rate x Frequency NS

Form x rate **

Form x frequency *

Rate x frequency *

Rate *

Figure 9. The contribution of grasses to vegetation cover at a) Gaisgill and b) Fassagh 2 in 2004, as influenced by rate, form and frequency of fertilizer application. Values in parentheses against the y-axis are values back-transformed to percentages.

At Fassagh 2, grasses were more abundant overall with high rate treatments compared to lower (medium) rate within the FRF series (P<0.05), with significant two-way interactions between rate and frequency, between form and rate (P<0.01), and between form and frequency (Figure 9b). Averaged over the two application frequencies within the FRF series, high rate inorganic treatments were significantly more grassy than lower rate inorganic ones (P<0.001), or than FYM at either rate (both (P<0.01). However, averaged over the two rates of application, grass content was higher with intermittent FYM treatments compared to others (P<0.01 compared to annual FYM). The overall pattern shown in Figure 9b suggests that, with inorganic fertilizers, grasses were more influenced by rate of application than by frequency, but with FYM, frequency of application was more important. However, in the absence of

42

a significant three-way interaction, this conclusion can only be tentative. As at Gaisgill, H. lanatus was the dominant grass at Fassagh 2 and the trends described also reflect those in this species, though less markedly so than at Gaisgill. With inorganic treatments, particularly with annual applications, the differences due to application rate reflect those shown not only by Holcus but also by several less abundant species together, e.g. Cynosurus cristatus, Poa trivialis and Agrostis stolonifera. Similarly, the substantial difference between annual and intermittent FYM treatments at the lower rate is attributable both to H. lanatus and to small differences shown by several other species, in this case mainly A. stolonifera, Festuca rubra, Anthoxanthum odoratum, P. trivialis and Lolium perenne. By contrast, Holcus abundance did not differ between annual and intermittent FYM treatments at the high rate, and the small difference shown in overall grass content (see Figure 9b) was attributable to species such as Alopecurus pratensis, A. stolonifera, P. trivialis and L. perenne. The legume content of vegetation in 2004 was significantly affected by treatments at Bush but not at Gaisgill, whilst the effects of rate of application and FYM frequency were marginally non-significant in the FRF and LFF series respectively at Fassagh 2. At Bush, legume abundance showed a significant (P<0.05) treatment x year interaction when all treatments were included in the analysis, although the effect of treatments was not quite significant when 2004 data were analysed alone (P=0.058). Legumes peaked in abundance in 2002 with all treatments (overall back-transformed mean 20.8% in 2002 compared to 9.9% in 1999 and 10.7% in 2004). However, temporal trends differed in extent between treatments and by 2004 legume content was lowest on plots of treatments 15 (i.e. lime plus intermittent FYM, 3.5%) and treatment 18 (HPS organic pellets at the high rate, 3.9%). Neither of these means was significantly different from nil input control (9.8%) in 2004, based upon the year x treatment analysis, although both differed significantly from several other treatments, notably high rate intermittent and low and medium rate annual applications of FYM and medium rate inorganic fertilizers (P<0.05 compared to medium rate annual FYM, P<0.01 the remainder). The higher legume content of the latter treatments was reflected in a significant (P<0.05) rate x frequency interaction for 2004 data within the FRF series (Figure 10a) and a nearly significant (P=0.066) effect of FYM frequency within the LFF series. Within the latter series, highest legume content resulted from annual FYM applications (13.5%) compared to intermittent (6.1%) or nil FYM (11.2%), all averaged over + and – lime treatments. Averaged over FYM and inorganic equivalent treatments within the FRF series analysis, legume content was highest with high rates applied intermittently, significantly higher than with high rates applied annually, whilst legume content with the latter combination was also significantly lower than with annual applications at the lower rate (both P<0.05) (Figure 10a). No other difference was significant within this series.

43

0.2

0.3

0.4

0.5

1


Arc

sin-

sqrt

( p o

f cov

er)

Medium MediumIntermittent Annual

High HighIntermittent Annual

a) Rate x Frequency *(23.0)

(15.2)

(8.7)

(3.9)

0.2

0.3

0.4

0.5

0.6

1999 2000 2001 2002 2003 2004Year

Arc

sin-

sqrt

(p o

f cov

er)

- Lime + Lime

Lime x Year ***

b)

(23.0)

(15.2)

(8.7)

(3.9)

(31.9)

Figure 10. The influence of treatments on the contribution of legumes to vegetation cover at Bush: (a) the effect of rate and frequency of fertilizer application on legume content in 2004 and (b) the influence of lime application on changes in legume content 1999-2004. Values in parentheses against the y-axes are values back-transformed to percentages.

Lime application tended to result in lower legume content overall at Bush in 2004 (12.0% compared to 8.2%), although this difference was not statistically significant in the analysis of 2004 data alone (P=0.092). However, there was a highly significant (P<0.001) interaction between lime and year within the LFF series, reflecting markedly different temporal patterns in legume content between limed and un-limed plots (Figure 10b). Legume content declined until 2001 in the absence of lime application (P<0.01 in 2001 compared to1999) but remained stable on limed plots, then increased significantly in both cases in 2002 (P<0.001 for the increase with both limed and un-limed treatments). This increase was particularly marked on limed plots, so that, in 2002 legume content was significantly higher on limed plots than on un-limed ones (P<0.001). However, legumes declined significantly by the following year on limed plots (P<0.001) and again between 2003 and 2004 (P<0.05), but declined more slowly between 2002 and 2004 on un-limed plots (P<0.05 by 2004 compared to 2002). By 2004, legumes were significantly more abundant on these plots than on limed ones in this analysis (P<0.05). At Fassagh 2 as at Bush, legumes tended to be more abundant with annual FYM application when averaged over + and – lime treatments (22.0%, compared to 14.2% and 13.7% for intermittent and nil FYM respectively), although the FYM frequency effect was not quite significant at this site (P=0.057). Legumes tended also to be more abundant with medium rate fertilizer application compared to the high rate at Fassagh

44

2, averaged over both forms of fertilizer and both frequencies of application (21.2% compared to 14.2%, P=0.051).

Table 9. The effects of treatments on bryophytes and five composite vegetation variables at the semi-improved site in Cumbria (Gaisgill) in 2004. Values for bryophytes are means of arcsine-square root transformed data (see text), while figures in parentheses are means back-transformed to % of live vegetation cover. See Table 2 for explanation of treatment numbers. Significance of ANOVA treatment: NS, P>0.05; *, P<0.05; **, P<0.01; ***, P<0.001. SEDs and degrees of freedom (df) in italics indicate data adjusted for covariance with 1999 data.

Weighted scoresBryophytes % of vegetation cover

British Ellenberg Plant strategyTreatment N R C radius S radius R radius

1 0.19 (3.4) 4.43 5.24 2.71 2.77 3.042 (0.0) 5.28 5.82 2.94 2.46 3.02

3 0.14 (2.0) 4.49 5.36 2.74 2.78 3.044 0.10 (0.9) 4.50 5.47 2.74 2.81 3.065 0.06 (0.3) 4.76 5.54 2.89 2.73 2.976 0.14 (2.1) 4.65 5.55 2.76 2.66 3.067 0.20 (4.0) 4.58 5.48 2.76 2.76 3.048 0.14 (1.9) 4.74 5.45 2.74 2.56 3.06

9 0.15 (2.3) 4.34 5.31 2.75 2.84 3.0310 0.14 (2.0) 4.74 5.55 2.82 2.68 3.0311 0.21 (4.4) 4.33 5.36 2.74 2.84 3.0412 0.19 (3.6) 4.56 5.53 2.75 2.71 3.07

13 0.17 (2.9) 4.76 5.70 2.75 2.63 3.1114 0.07 (0.5) 4.83 5.60 2.80 2.63 3.0615 0.14 (2.1) 4.68 5.46 2.72 2.59 3.05

16 0.16 (2.6) 4.57 5.51 2.79 2.77 3.0217 0.13 (1.8) 4.64 5.53 2.78 2.66 3.0618 0.12 (1.5) 4.72 5.64 2.87 2.77 3.0219 0.15 (2.1) 4.54 5.33 2.78 2.74 3.02

SED 0.037 0.154 0.121 0.051 0.078 0.028df 34 35 35 36 36 35

* *** * ** *** *

Among the three semi-improved sites, bryophytes reacted significantly to treatments only at Gaisgill. At this site, bryophytes tended to increase on plots of most treatments after 2000, with the notable exception of treatment 2, where they were recorded only in 1999 and 2003 (at less than 0.1% of vegetation cover in both years). This treatment was the only one for which no bryophyte cover was recorded in 2004 and it was therefore excluded from the analysis of 2004 data. Increases in bryophyte cover were particularly noticeable on nil input control plots, those receiving intermittent FYM treatments at the medium rate and intermittent inorganic treatments at both the medium and the higher rate, and on lime only plots, though not where FYM was applied annually to limed plots. In 2004, the latter plots and those that had received annual FYM applications at medium or high rates without lime all supported

45

significantly lower levels of bryophyte cover than nil input controls (P<0.01 compared to treatment 5, the high rate of annual FYM) (Table 9). Intermittent FYM treatments at both medium and high rates allowed significantly higher proportions of bryophytes than equivalent annual treatments (P<0.01 for the medium rate). Bryophyte content declined approximately linearly with increasing rate of FYM between treatments 1-5, but showed no such response with corresponding rates applied intermittently. Annual applications of FYM to limed plots reduced bryophyte cover compared to plots that had received lime only (P<0.01). Overall however, liming reduced bryophyte cover within the LFF series (2.8% compared to 1.5% for –lime and +lime respectively, P<0.05) and there was no significant interaction between lime and FYM application. Averaged over + and - lime treatments within this series, annual FYM application significantly reduced bryophytes compared to either nil FYM (P<0.001) or intermittent FYM (P<0.01) and the overall difference between annual and intermittent treatments was also significant within the FRF series (P<0.01). Overall, FYM treatments reduced bryophytes compared to inorganic equivalents within this series (P<0.01), and annual applications produced lower bryophyte cover than intermittent treatments (P<0.001).

Effects on weighted British Ellenberg indices

Weighted British Ellenberg N indices (N scores) were significantly influenced by treatments at Gaisgill but not at Fassagh 2 or Bush. At Gaisgill, N scores tended to be highest in 2003 under most treatments, declining significantly between 2003 and 2004 on several plots, including nil input control plots. Scores showed an overall decline between 1999 and 2004 on the latter (P<0.001), whereas with treatment 2 (continuation of past inputs), scores rose significantly until 2002 (from 5.18 to 5.91, P<0.001), declining significantly between 2003 and 2004 (P<0.001). Nevertheless, in 2004, the mean N score for treatment 2 remained very significantly higher than for all other treatments (P<0.001 for all treatments except treatments 5, 8, 10, 13 and 14, for which P<0.01) (Table 9). By contrast, the mean N score for nil input control in 2004 was lower than for any other treatment except annual and intermittent inorganic fertilizers at the medium rate (treatments 9 and 11 respectively, i.e. the lowest rate of inorganic treatment applied), significantly so compared to treatments 2, 5, 8, 10, 13 and 14 (P<0.001 for treatment 2, P<0.05 for the remainder). Mean N scores were positively related to increasing rate of FYM across the full range 0-24 t ha -1 applied either annually (i.e. treatments 1 and 2-5) or intermittently (treatments 1 and 6-8) although less clearly so with the latter. N scores differed very little between annual FYM at the high rate (treatment 5) and the inorganic equivalent (treatment 10), but at other rates and frequencies within the FRF series, mean scores were consistently higher for FYM treatments compared to inorganic equivalents, leading to a significant overall effect of form of fertilizer (P<0.05). High rate treatments produced consistently higher mean scores than corresponding lower rates, including a significant difference between treatments 9 and 10 (P<0.05), leading to a significant overall effect of rate (P<0.01). Scores did not differ significantly among treatments 16-19 (organic pellets and their inorganic equivalents) and these treatments did not differ significantly from any other except treatment 2. Despite higher N scores on lime-only plots compared to nil input controls (P<0.05), treatments combining lime and FYM application (treatments 14 and 15) did not differ from their –lime

46

counterparts, so that there was no overall effect of lime application within the LFF series. Weighted British Ellenberg R scores were significantly influenced by lime at Gaisgill but less so at Bush, and there was no significant treatment effect on this variable at Fassagh 2. However, a near-significant (P=0.076) form x frequency of application interaction within the FRF series at the latter site showed relatively high means scores in 2004 following intermittent FYM treatments (5.81) compared to annual FYM (5.61) or intermittent inorganic treatments (5.66). At Gaisgill, Ellenberg R scores increased progressively between 1999 and 2004 on plots that received lime only (treatment 13), whilst on most other plots, including those that received both lime and FYM (treatments 14 and 15), scores were highest in 2002 and declined thereafter. Nil input controls were among the exceptions to the latter trend, with scores declining overall between 1999 and 2004, so that the mean score for this treatment was the lowest of all treatments in 2004 (Table 9). The difference between these plots and those of treatment 13 was highly significant in 2004 (P<0.001). This difference accounted entirely for the overall significant effect of lime within the LFF series (P<0.05), since there was no consistent effect of lime by 2004 where FYM was also applied. However, the highest mean Ellenberg R score in 2004 was that for treatment 2, which had shown a marked increase between 1999 and 2002 (5.53 to 5.91), followed by a relatively small decline. The 2004 score for this treatment was significantly higher than all others except treatments 13, 14 and 18 (P<0.001 compared to treatments 1, 3, 9, 11, and 19, P<0.05 the remainder). At Bush, the mean Ellenberg R score for the lime-only treatment differed only from treatments 16 and 18 (organic pellets at the lower and higher rates) in 2004 (Figure 11), reflecting a slight overall decline between 1999 and 2004 with both the latter treatments and overall increases on limed plots. Inorganic equivalents to the organic pellets showed no decline in R score, with a very substantially higher mean score on plots of treatment 19 compared to treatment 18 in 2004 (P<0.001). However, scores for limed treatments did not differ from their non-limed counterparts within the LFF series, so that there was no overall effect of lime application and no lime x FYM interaction. However, there was a significant form x rate x frequency of application interaction within the FRF series (P<0.001), represented by a higher mean score for intermittent FYM application at the lower rate (treatment 7) compared to both the inorganic equivalent (treatment 11) and annual FYM at the same rate (treatment 4) (both differences P<0.05).

4.5

5.0

5.5

6.0

1,2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Treatment

Br.

Elle

nber

g R

LSD treatments 3-19LSD Treat. 1,2 vs. others

Figure 11. The effect of treatments on weighted British Ellenberg reaction (R) score at Bush in 2004. Error bars are least significant differences (LSDs) at P<0.05.

47

Effects on C, S and R radius scores

Weighted competitor (C radius), stress-tolerator (S radius) and ruderal (R radius) scores were not influenced by treatments at Fassagh 2 or Bush, but showed marked effects at Gaisgill. As with Ellenberg N scores, the most prominent differences in C radius and S radius scores at Gaisgill in 2004 were those between treatment 2 (continuation of past inputs) and remaining treatments (Table 9). C radius scores were higher for this treatment than all others except treatment 5 (24 t FYM ha-1 annually) and treatment 18 (organic pellets at the higher rate) (P<0.001 for all except treatments 6, 10, 14, 16, 17 and 19). Nil input controls differed only from treatments 2, 5, 10 and 18 (P<0.05 for all except treatment 2), whilst treatment 13 differed from each of these except treatment 10. There was no overall effect of lime application on C radius score, and no effect of form, rate or frequency of fertilizer application. Weighted S radius scores for treatment 2 were significantly lower than for all other treatments at Gaisgill except for treatments 8 and 15 (P<0.001 for treatments 1, 3, 4, 7, 9 and 18). In addition to treatment 2, nil input control differed only from treatments 8 and 15 (P<0.05). Mean scores for limed treatments in 2004 were consistently lower than for their non-limed counterparts, significantly so for treatments 14 and 15 compared to treatments 4 and 7 (both P<0.05), and the overall effect of lime was significant in 2004 within the LFF treatment series (P<0.01). This reflects a significant overall increase between 1999 and 2000 on un-limed plots (P<0.001) but not where lime was applied, although there were significant temporal fluctuations on both limed and un-limed plots, with a significant lime x year interaction overall (P<0.05). Mean weighted ruderal (R radius) scores in 2004 were highest for the lime-only treatment and lowest for high rate FYM applied annually (treatment 5). However, the effect of lime on plots that also received FYM was negligible compared to corresponding un-limed plots, so that a marginally non-significant overall effect of liming (P=0.054) can be attributed to the significant difference between the lime-only treatment and nil input control, particularly as the difference between lime-only and lime plus intermittent FYM (treatment 15) was also significant (P<0.05). Treatment 5 differed significantly from all others except treatments 2, 16, 18 and 19 (P<0.001 compared to treatments 12 and 13), but apart from these differences there was no indication of any effect of form, rate or frequency of fertilizer on the ruderal characteristics of the plant community.

Discussion

THE EXPERIMENT SITES

Unimproved sites

Species-richness at Raisbeck (average 26.0 and 25.7 species m-2 in 1999 and 2004 respectively) was typical of MG3 NVC communities (Rodwell, 1992), lying within the range identified from a large sample of MG3 meadows surveyed by English Nature. These averaged 22.4 and 29.8 species m-2 for the ten highest and ten lowest sites respectively, with an overall mean of 23.7 species m-2 (Critchley, Burke & Fowbert, 1999, unpublished report to Defra). This overall mean was exceeded by all treatments means at Raisbeck in 2004 except that for annual FYM at the high rate of 24 t ha-1 (i.e. 22.1 species m-2). Corresponding values from surveys of MG5 grasslands (Gibson, 1995, 1996), also summarised by Critchley et al., show a similar overall

48

mean value (23.6 species m-2), though with a wider range (15.1 and 33.5 species m-2

for the lowest and highest ten fields respectively) possibly reflecting a more diverse range of management regimes. The plant communities at the unimproved sites in Fermanagh (Fassagh 1) and Wales (Pentwyn) were less species-rich than at Raisbeck, with levels lower at both sites than the average for the MG5 survey sample. However, treatment means at Pentwyn in 2004 ranged between 18.2 and 22.6 species m-2 and all therefore lay within the broad MG5 range. The range at Fassagh 1 (14.3 - 18.6 species m-2) corresponded more closely with the lower end of the MG5 sample. The slightly lower than expected species-richness at Pentwyn may, at least in part, reflect the fact that bryophytes were not recorded to species level (in contrast with other sites), and also that no sedge species were present. The absence of sedges may, in turn, represent the residual effects of (unrecorded) past fertilizer inputs. Anecdotal information suggests that basic slag may have been applied to the site at some time in the past. However, the low soil P levels (4.5 per 100g in 1999) indicate a potential for maximal species-richness (Jannsens et al., 1998) and do not suggest any remaining effect on soil chemistry previous inputs. The even lower species-richness at Fassagh 1 probably reflects the past use of moderate inputs of fertilizer (i.e. 50:11:21 kg ha-1 year-1 of N:P:K for the preceding four years and unspecified amounts of FYM before that), although there was no evidence at this site of an increase in species-richness on nil input control plots during the course of the experiment. Despite the fact that vegetation communities at Fassagh 1 and at Pentwyn in particular were initially closer to MG5 communities on the basis of their botanical composition (Kirkham et al., 2002), levels of species-richness at these sites were more typical of MG7 (Lolium perenne leys and related grasslands) and MG6 (Lolium perenne-Cynosurus cristatus grassland) NVC communities respectively (Critchley et al., unpublished report to Defra, 2004). Moreover, it is worth noting that, although the vegetation at Fassagh 1 in 1999 corresponded more closely with MG5 than any of the other recognised NVC communities, the similarity was lower than that shown by the vegetation at Pentwyn and much lower than the correspondence between the vegetation at Raisbeck and MG3. The overall community at Fassagh 1 had some similarities with the M23 Juncus effusus/acutiflorus-Galium palustre rush pasture (Rodwell, 1991) and the more mesotrophic MG10 Holcus lanatus-Juncus effusus rush pasture (Rodwell, 1992). The original NVC surveys were not carried out in Northern Ireland (Rodwell, 1992) and it is probable that such surveys might have identified additional grassland plant community types to those found on mainland UK, possibly including one that more closely corresponds to the vegetation at Fassagh 1. Furthermore, there has been a general shift in species composition at Fassagh 1 over the six years of the experiment, with even nil input control plots now more similar to MG6 communities (R.A. Sanderson, unpublished data). Smith et al. (2003) identified target Ellenberg fertility (N) values for MG3b NVC communities as between 4.33 and 4.67, based upon the floristic tables for this sub-community (Rodwell, 1992). These values were weighted using the relative cover abundances of the constituent species, as in the present study. The overall mean value for the unimproved site in Cumbria (Raisbeck) lay within these limits in both 1999 and 2004. Mean values for several treatments, including nil input control and lime-only (i.e. 4.31 and 4.27 respectively), were below the lower limit in 2004, but none exceeded the upper limit. Target Ellenberg N values are not available for MG5 communities, but the range of values at Pentwyn in 2004 (4.23 - 4.60) corresponds fairly closely with the target range for MG3b. The range at Fassagh 1 was somewhat lower (3.44 - 4.49), probably reflecting to some extent the prevalence of Juncus

49

acutiflorus and J. conglomeratus which have British Ellenberg N scores of 2 and 3 respectively. Average values for unweighted stress-tolerator (S) and ruderal (R) radius scores for both these sites in 2004 (see Table 4) lie well within the ranges identified from the MG5 survey sample referred to above (Gibson, 1995, 1996), i.e. S radius means of 3.15 and 2.57 for the highest and lowest ten sites respectively (overall mean 2.85) and R radius means of 2.40 and 3.05 (overall mean 2.73). The average competitor (C radius) score at Fassagh 1 in 2004 (2.85) exceeded that for the ten highest fields in the MG5 sample (2.79), although the 1999 mean of 2.73 lay within the range of 2.28 – 2.79, overall mean 2.54). The 2004 mean for Pentwyn (2.47) lay well within this range. Average unweighted S radius scores at Raisbeck were close to the average of 2.90 for the highest ten sites in the English Nature MG3 sample, whilst averages for both the C radius and R radius unweighted scores were slightly above the corresponding mean values for the MG3 sample of 2.39 and 2.71 respectively. Weighted radius scores differed somewhat from corresponding unweighted values (Table 4) and were much more sensitive to treatments, since a change in unweighted means is dependant upon species turnover. No detailed analysis was carried out on unweighted C, S or R values in this study, but preliminary analyses showed no apparent treatment effect on these. In the absence of target weighted values for MG3 and MG5 communities it is not possible to say if or to what extent treatments shifted values outside a target range. The magnitude of differences in weighted C, S and R scores were such that, as with Ellenberg N scores, the changes observed at the unimproved sites would probably have been within target ranges had these been identified, with the possible exception of C radius scores at Fassagh 1 which increased with all treatments. However, this should not be taken to imply that the changes caused by the high rate FYM treatments, for example, are acceptable, since they indicate a deterioration in ecological quality of these communities.

Semi-improved sites

By 2004, average species-richness differed little among all three semi-improved sites (15 species m-2). This level is probably typical of a wide range of MG7 grasslands, though somewhat lower than the average of 18.2 species m-2 for MG7 grasslands within the Pennine Dales ESA (Critchley et al., unpublished report to Defra, 2004). The similarity in 1999 of Gaisgill and Fassagh 2 to MG7 communities was confirmed on the basis of their floristic composition, but Bush was botanically much closer to MG6 (Kirkham et al., 2002). British Ellenberg N values (unweighted) for Gaisgill and Fassagh 2 correspond with those for MG7 in the Pennine Dales ESA sample (mean 4.87), whereas those at Bush were somewhat lower both than the corresponding average for MG6 within that sample (4.56) and that for MG3 (4.52), with weighted values lying within the range identified by Smith et al. (2003) for MG3b. Similarly, S radius scores at Bush were higher than at the other semi-improved sites and were more typical of those for MG5 (Critchley, Burke & Fowbert, 1999, unpublished). Those for Gaisgill and Fassagh 2 were somewhat higher than the averages reported for MG6 in the Somerset Moors and Levels and the Pennine dales ESAs in the same study (about 2.11 overall). Average unweighted C and R radius scores at Gaisgill were very similar to average for MG6 in these two ESAs (2.70 and 3.20 respectively), whilst those at Fassagh 2 were somewhat lower and higher respectively.

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RESPONSE TO FERTILISERS - COMPARISON WITH RESULTS OF PREVIOUS STUDIES

Early work on the effects of fertilizers on the botanical composition of UK grassland (e.g. Lawes & Gilbert, 1859; Lawes, Gilbert & Masters, 1882; Gilchrist, 1906; Kinch & Stapledon, 1911, 1912; Brenchley & Warrington, 1958; Arnold, Hunter & Gonzalez Fernandez, 1976; Williams 1978) concentrated heavily on the response of individual species and of groups of species, for example grasses, legumes and ‘others’ (mainly herbs and sedges). A general conclusion from these and a wide range of other studies in the UK and mainland Europe is that fertilizers, particularly those containing substantial amounts of N, reduce species-richness and increase the proportion of grasses in the vegetation at the expense of legumes and other dicotyledonous species (herbs); P and K applied without N often increase the legume content - see reviews in Chalmers et al. (2000) and in more detail in Kirkham (1996). More recent work in meadows on the Somerset peat moors (Mountford, Lakhani & Kirkham, 1993; Mountford, Lakhani & Holland, 1996; Kirkham, Mountford & Wilkins, 1996) and in the Pennine Dales (Smith, 1988; Smith et al., 1996, 2000, 2002) has confirmed the detrimental effects of inorganic fertilisers on meadow vegetation. Whilst individual grass, herb and legume species do not always follow these general rules, the use of these plant groupings to characterise vegetation response to experimental fertilizer treatments is valid on scientific grounds. Most grasses share a number of characteristics that can account for their generally superior response to N inputs compared to other groups, namely their more rapid accumulation of biomass in spring (Grime, 1980), their more efficient N metabolism, a larger proportion of roots in the upper soil layer, better water economy - which is improved by N application (Garwood & Williams, 1967; Garwood, 1988) – and tall growth giving more efficient light interception (Rabotnov 1966, 1977). Legumes are favoured by P and K application without N, since this, coupled with their ability to fix N, compensates for a less ramified root system and poorer root cation exchange ability compared with grasses (Gray, Drake & Colthy, 1953; Mouat & Walker, 1959; Jackman & Mouat, 1972). The response of the grass and herb groups in this study were generally consistent with the results of past studies. The increase in legumes following moderate levels of FYM and inorganic equivalents at Welsh sites may have been in response to the constituent P and K rather than N, reflecting low soil P and K levels in 1999 compared to other sites (about 16.0 and 11.5 mg K per 100g and 4.5 and 5.3 mg P per 100g at Pentwyn and Bush respectively, compared to 7.2-29.5 mg P and 23.0-116.0 mg K per 100g at other sites). Higher inputs reduced legume content at the Welsh sites, particularly the organic pellet treatments and their inorganic equivalents (note that these treatments contained lower ratios of P and K to N compared to FYM – see Table 2). Bryophytes were also sensitive to fertilizer treatments at most sites, even though, except at Fassagh 1, these were of low abundance. This agrees with previous results showing a negative response of Brachythecium rutabulum to fertilizers in meadows on a Somerset peat moor where this species was the most common bryophyte present (Kirkham et al., 1996). Nevertheless, the effects recorded here have generally been small compared to most previous fertilizer experiments. This reflects the lower levels of nutrient addition involved compared to those used in other studies where rates used have been typically at least 25 kg N ha-1 year-1, extending to considerably higher rates. A recent study carried out in Devon and Buckinghamshire has shown that grassland communities with 12 species of higher plant or more were found only where less than 50 N ha -1

year-1 and the most species-rich communities (e.g. >10 forb species) were associated

51

with N inputs not exceeding 15 kg N ha-1 year-1 (Tallowin et al., 2005). The latter finding accords with critical N loads for neutral grassland suggested by Bobbink & Roelofs (1995). With the exception of those treatments applied at Gaisgill and the Fermanagh sites that represented a continuation of past inputs, only the high rate organic pellet treatments and their inorganic equivalents provided levels of N exceeding 15 kg N ha-1 year-1. However, several treatments included levels of P and K equivalent to or greater than those used in conjunction with N in past studies (e.g. Mountford et al., 1993) and greater than those that would be applied with a standard commercial form of compound fertiliser to deliver 25 kg ha-1 of N (i.e. 5.4 kg P and 10.4 kg K per ha). At least one past study has attributed botanical change to the application of P where this element was shown to be the limiting element (Kirkham et al., 1996). Nevertheless, it was not the intention in this study to differentiate between the effects of the different chemical constituents of the fertiliser applied, and the amounts of applied P and K in particular were closely correlated across all the treatments at each site. At Raisbeck, amounts of N, P and K were all absolutely correlated, since all fertiliser treatments were related to different rates of FYM. At other sites, amounts of P and K were less closely correlated with N, since the inclusion of the organic pellets treatments and their inorganic equivalents at Gaisgill and the two Welsh sites gave some variation in P and K independently of N, as did the treatments representing continuation of past inputs at both Gaisgill and the two Fermanagh sites.

RESPONSE TO AMOUNTS OF NUTRIENTS APPLIED

The three rates of FYM used, applied either annually or intermittently, provide a fairly comprehensive range of seven application rates of each nutrient (including nil) when averaged over the six years of the study, with four rates applied as inorganic fertilizer (five rates including nil). At sites where organic pellets and their inorganic equivalents were included, these provide an additional two rates of nutrient input per form. Plotting 2004 treatment means for selected variables against the mean amounts of N applied per year reveals several significant correlations (Figures 12 and 13). Similar plots made for the Irish and Welsh sites with amounts of N replaced by corresponding amounts of P or K reveal no relationship that was not illustrated adequately by plotting variables against applied N. Species-richness at Raisbeck was related in non-linear fashion to amounts of N applied as FYM, with no apparent effect of rates that provided up to 6 kg N ha-1 year-1

(Figure 12a). This range encompasses annual or intermittent applications of FYM at 6 t ha-1 and intermittent applications at either 12 or 24 t FYM ha-1, whilst annual rates of 12 and 24 t FYM ha-1 both exceed the implied threshold. It is interesting to note that although 12 t FYM ha-1 applied annually represented a continuation of past inputs to the site, a slight decline in species-richness had been noted over the six year period on these plots, though the decline was not statistically significant and not as great as occurred with annual applications of 24 t ha-1. Where FYM application ceased, on nil input control plots and those that received lime only, species-richness increased slightly, though again, not significantly so. It is also interesting to note that although there was no significant overall difference in species-richness between FYM and equivalent inorganic fertilisers, the correlation with the amount of N applied was not significant for inorganic treatments alone.

52

R2 = 0.82

R2 = 0.83

40

45

50

55

60

65

70

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Mean N applied 1999-2004 (kg N ha-1 year-1)

Her

bs %

of c

over

Linear ( All) Linear (FYM)

R2 = 0.45

R2 = 0.55

4.2

4.3

4.4

4.5

4.6

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Mean N applied 1999-2004 (kg N ha-1 year-1)

Wei

ghte

d B

r. E

llenb

erg

N

R2 = 0.68

R2 = 0.90

2.6

2.8

3.0

3.2

3.4

3.6

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


Wei

gted

S ra

dius

sco

re

R2 = 0.55

R2 = 0.80

20

22

24

26

28

30

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


Spe

cies

m-2

Inorganic FYMFYM + Lime Linear ( All)Poly. (FYM)

a) b) c)

d)

R2 = 0.82

3.0

3.5

4.0

4.5

5.0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8Mean N applied 1999-2004 (log10kg N ha-1 year-1)

Wei

ghte

d B

r. E

llenb

erg

N

e)

R2 = 0.24

0

5

10

15

20

25

0 2 4 6 8 10 12 14 16 18 20 22 24 26


Legu

mes

% o

f cov

er

Poly. ( All) Linear (FYM)f)

Figure 12. Relationships between the mean amounts of N applied per year at unimproved sites and four selected plant community variables in 2004. Lines are fitted to the values shown and R2 values are given where these indicate a significant (P<0.05 or greater) correlation. Lines for FYM are fitted using all treatments where FYM was applied (including FYM + lime), plus the nil input control and lime only treatments. Only variables showing a significant relationship are shown for each site: a)-d) Raisbeck; e) Fassagh 1; f) Pentwyn. Values on the x-axis for e) are calculated by: x = log10 (kg N ha-1 year-1 + 1.0)

53

R2 = 0.57

10

12

14

16

18

20

0 5 10 15 20 25 30 35 40 45 50 55 60


Spe

cies

m-2

Inorganic FYMFYM + Lime Organic pelletsPellets inor. equivalent ContinuationLinear ( All) Linear (FYM)

a)

R2 = 0.48

4.0

4.5

5.0

5.5

0 5 10 15 20 25 30 35 40 45 50 55 60


Wei

ghte

d B

r. E

llenb

erg

N

R2 = 0.35

2.2

2.4

2.6

2.8

3.0

3.2

0 5 10 15 20 25 30 35 40 45 50 55 60


Wei

ghte

d S

radi

us s

core

Poly. ( All) Linear (FYM)

b)

R2 = 0.27

10

12

14

16

18

20

0 2 4 6 8 10 12 14 16 18 20 22 24 26


Spe

cies

m-2

c) d)

Figure 13. Relationships between the mean amounts of N applied per year and selected plant community variables in 2004 at semi-improved sites. Only variables showing a significant relationship are shown for each site: a) – c) Gaisgill; d) Bush. Other details as in caption to Figure 12.

Weighted stress-tolerator scores showed somewhat similar relationships with the amounts of N applied, although the relationships were linear with no suggestion of a threshold level (Figure 12d). The proportion of herbs in vegetation cover also declined significantly and in linear fashion with increasing amounts of applied N, while British Ellenberg N scores increased (Figures 12b and c respectively), but with no difference between the overall relationship and that for FYM treatments alone in either case. Unimproved sites in Fermanagh and Wales were generally less sensitive to nutrient inputs, with only British Ellenberg N scores related (positively) to amounts of N applied as FYM at Fassagh 1 (Figure 12e) and legume cover at Pentwyn showing a non-linear negative overall response to applied N (Figure 12f). The latter effect was marginal and was largely attributable to the higher rate organic pellet treatment and its inorganic equivalent and to increases in legume abundance with intermediate levels of N input. Relationships at semi-improved sites were also fewer and less marked. At Gaisgill, overall negative relationships to applied N were attributable to the high total amount applied in the continuation of past inputs treatment. However, the pattern shown for species-richness (Figure 13a) tends to confirm trends described earlier suggesting that

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recovery of species-richness was inhibited by FYM treatments supplying more than 6 kg N ha-1 per year. As with legume cover at Pentwyn, the fairly marginal overall negative relationship between species-richness and amounts of applied N at Bush is attributable to the high rate organic pellet treatment and its inorganic equivalent. As already noted, the amounts of N needed to cause the effects described here are relatively small in general terms, but particularly so in relation to the levels of atmospheric N deposition experienced at the sites in Cumbria and south Wales, i.e. >25 kg N ha-1 year-1 in Cumbria and 20-25 kg N ha-1 year-1 in Wales, although N deposition in Fermanagh is much lower at <12 kg N ha-1 year-1 (NEGTAP, 2001). Of the three unimproved sites, Raisbeck was both the most species-rich and the most sensitive to treatments, the latter possibly a consequence of the former. It is also possible that, since annual atmospheric deposition at the site exceeds the critical N load for neutral grassland (Bobbink & Roelofs, 1995), there is no ‘margin of freedom’ within the system there. Any additional input of N therefore adds to the already negative effect of N deposition. The results of a recent study of acid grasslands in the UK (NVC U4 communities – Rodwell, 1992) suggest that this may be the case: species-richness showed a negative linear response to geographic variation in atmospheric N deposition across the range 5-35 kg N ha-1 year-1 (Stevens et al., 2004). The apparent slight downward trend in species-richness during the course of the experiment at Raisbeck may be part of a longer term trend at the site as a whole. However, there was no such trend apparent in weighted stress tolerator score (which tended to increase), and weighted British Ellenberg N indices declined overall, though not with those treatments that gave the higher rates of mean annual N input. A further possibility is that, as a consequence of the high rates of annual atmospheric N deposition at Raisbeck, N is not the limiting nutrient and response to fertilisers may therefore be attributable to the inputs of P and/or K, rather than N. However, this would not appear to explain the apparent difference in sensitivity between Raisbeck and Pentwyn, since soil P and K levels in 1999 were low at both sites and both were marginally lower at Pentwyn than Raisbeck (4.5 compared to 7.2 mg per 100g extractable P and 15.7 compared to 25.0 mg per 100g extractable K for Pentwyn and Raisbeck respectively). However, the low soil fertility at Pentwyn may provide some buffering in the system, as suggested by increases in legume content with moderate levels of fertiliser input, or the apparently lower sensitivity may simply reflect a lower overall density of species compared to Raisbeck (see Appendix). The vegetation at Fassagh 1 was also notably less species-rich than at Raisbeck, with soil P and K levels considerably higher than other unimproved sites (24.7 and 68.7 per 100g extractable P and K respectively). These levels presumably reflect the relatively high amounts of fertiliser used at the site in the recent past. Amounts of N, P and K applied in the experimental treatments therefore represent comparatively small inputs relative to past fertiliser usage. Soil P levels were high at Gaisgill (29.5 mg per 100 gm in 1999). With the exception of the treatment representing a continuation of past inputs, the highest N inputs at Gaisgill, and the highest ratio of N to P, were provided by the high rate organic pellet treatment and its inorganic equivalent. There was some suggestion that these treatments inhibited recovery of species-richness compared to treatments receiving less N (Figure 13a), but the effects were very marginal and was not supported by trends in British Ellenberg N index or stress-tolerance scores (Figures 13b and c). As noted above, these treatments were entirely responsible for the overall negative relationship between applied N and species-richness at Bush, implying that N was the element responsible. However, the effect was marginal here too and highest

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species richness occurred at moderate levels of nutrient input. Initial soil P and K levels were lower at this site than at other semi-improved sites (5.3 and 11.5 mg per 100 gm respectively), reflecting the absence of any fertiliser inputs in the recent past.

DIFFERENCES BETWEEN ORGANIC AND INORGANIC FERTILISERS

As already noted, there appears to have been no other study that has attempted to match the N, P and K inputs in the form of FYM with exact inorganic equivalent amounts. One of the expectations of doing so was that FYM would be less damaging than inorganic equivalent treatments, if only because of the beneficial effects of FYM on soil fungi compared to inorganic fertilizers (Sparling & Tinker, 1978; Bardgett, 1996; Bardgett et al., 1997). Few statistically significant differences were shown between the two forms of fertilizer in this study. However, where differences were apparent at unimproved sites, e.g. with legume content, competitor and ruderal scores at Raisbeck, with grass and bryophyte cover at Fassagh 1, and with bryophyte cover, MG5 indicator species-richness and stress tolerators scores at Pentwyn, the effects of FYM on vegetation quality were more often negative than were those of equivalent inorganic treatments. This generalization did not apply at semi-improved sites. There were fewer overall differences between forms of fertiliser at semi-improved sites, and if anything the effects of FYM were less negative than those of inorganic treatments at these sites. Differences in the rate of release of nutrients between the two forms of fertiliser may account for these effects. It is possible that, where nutrient availability is low, the rapid release of nutrients from inorganic fertilisers may allow the less competitive species access to these nutrients compared to the situation where they are released more slowly from FYM. In the latter case, grasses, with their shallower and better developed root systems, may be at an advantage over herbs and legumes. This is counter to the normal line of thinking which suggests that the more competitive species are better able to ‘mop up’ nutrients when they are applied in a readily available form. Physical differences between the two forms may also be significant. FYM is applied in lumps of varying size which can both cause localised smothering of existing plants and may also provide sites for seedling germination, either of seeds contained within the FYM itself or of those shed from the vegetation canopy. This may be advantageous for relatively early flowering and rapidly germinating species such as Poa trivialis which can germinate beneath an enclosed vegetation canopy (Williams, 1983; Hilton, Froud-Williams & Dixon, 1984), whilst a localised source of nitrate will also enhance germination (Williams, 1983). The physical properties of FYM may also account for the greater reduction in bryophyte cover compared to inorganic equivalents, since the fine structure and low growth habit of bryophytes are likely to make them more susceptible to smothering. Alternatively or in addition, reduced cover of bryophytes and other susceptible species may be a consequence of the taller and denser canopy formed by grasses compared to other species (Pigott, 1982). Further study into these aspects would be worthwhile. Another possible explanation for apparent differences between the two forms of fertiliser is that the amounts of N supplied by FYM over the six year period may have been underestimated. The MANNER model used to calculate N availability from FYM in this study predicts only the amount available in the season immediately following application (Chambers et al., 1999) and these were the amounts upon which the calculations of inorganic equivalent treatments were based. FYM may enhance the supply of N over a period of more than one year and with annual FYM applications,

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for example, this could have led to a slight underestimation of the amounts of N available over the six years in this study. Future versions of MANNER will address this issue, although the amounts involved are small. Furthermore, P and K supply were calculated as fixed proportions of the P and K composition of the FYM (Groves, Chambers & Williams, 1999; Anon, 2000) and the accuracy of matching the supply of these two elements between the two forms of fertilizer is heavily dependant upon the general applicability of these assumptions.

EFFECTS OF LIME APPLICATION

Lime application tended to increase the herb content of the vegetation at Raisbeck, Gaisgill and Pentwyn compared to other treatments, but to reduce herbs at the sites in Northern Ireland (Fassagh 1 and 2), though in all cases the effects were slight. An increase in herb cover at the expense of grasses is consistent with the results of the Park Grass Experiment (Williams, 1978 – see review of liming results by Tallowin, 1998). However, the effects were more marked in the Park Grass Experiment (PGE), reflecting the much longer time-scale involved, with lime applications repeated every five years. Analyses by Dodd et al. (1994) suggested that the species-impoverished MG6-type vegetation that had resulted from long-term application of ammonium sulphate could be restored to an approximation of an MG5 community by liming, although it was estimated that completion of this process might take 70-90 years. The results at Gaisgill are ambiguous in this context. Liming effects were more prominent at this site compared to others, reflecting the lower initial soil pH in 1999 (i.e. 4.7, compared to 4.9-5.1). Whilst increases in the herb/grass balance following lime application (particularly when combined with annual FYM application) provide some evidence of an initiation of a recovery process, this is contradicted by the lower stress tolerator scores and higher Ellenberg fertility scores resulting from liming, the latter in particular being consistent with a likely increase in macronutrient availability attributable to increased pH (van den Burgh, 1979; Tallowin, 1998). These results are supported by those of analyses based upon ordination of 2004 data in relation to NVC communities, in which all three limed treatments produced higher scores on the first axis (corresponding to a fertility gradient) than all corresponding un-limed treatments (R.A. Sanderson, unpublished). It is possible that a long period of time without nutrient input and with continual nutrient removal by hay cutting will be needed before any benefits of liming are fully evident at Gaisgill. At the semi-improved site in Wales (Bush), there was some evidence of increased species-richness with liming, especially when accompanied by annual FYM application (treatment 14). No fertilizer or lime had been used for some years before the experiments started at the Welsh sites and there may therefore be potential for a quicker recovery of vegetation quality by liming at Bush than at the other semi-improved sites. Nevertheless, lime treatments all tended to produce higher axis 1 scores than their un-limed counterparts in the 2004 ordinations for both Pentwyn and Bush, and in both cases the mean axis 1 score for treatment 14 was higher than that of any other treatment. Moreover, whilst at Pentwyn scores for all the lime treatments, including treatment 14, lay within the range encompassed by MG5b and c sub-communities, at Bush the mean score for treatment 14 lay at the high extreme of this range.

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IMPLICATIONS FOR SUSTAINABLE MANAGEMENT OF SEMI-NATURAL GRASSLAND

Despite being in an area of high atmospheric N deposition and, in addition, receiving moderate levels of FYM annually, Raisbeck is a good example of a species-rich MG3b NVC community (Rodwell, 1992). It was fairly clearly shown that annual applications of FYM at 24 t ha-1 year-1 will reduce vegetation quality at such sites, and this level of FYM therefore appears not to be sustainable for such communities. However, it is less obvious what level of FYM input is acceptable. This is partly because there were broad overall trends apparent in several of the variables - for example, an increase in the ratio of herbs to grasses, an increase in stress-tolerator score and a decline in Ellenberg fertility score - that were influenced differentially by treatments. Noticeable changes representing an apparent ‘improvement’ in quality often occurred on nil input control plots. Though these changes were fairly slight in most cases, they contributed, for example, to a linear response to the rate of FYM applied in terms of treatment means in 2004. Judgements are further hampered somewhat by year-to-year variation within individual treatments that tended to obscure any overall trend. One approach is to relate everything to the ‘continuation’ treatment each year, but this makes the possibly dangerous assumption that that treatment itself is sustainable. The small overall decline in species-richness with this treatment at Raisbeck (12 t FYM ha-1 annually) casts some doubt as to the sustainability of even this level at that site. This is supported by the finding that there appeared be a threshold represented by inputs of about 6.0 kg N ha -1 year-1 above which loss of species-richness occurred. Such losses could become significant in the longer term. Further support is provided by the ordination analysis mentioned above, that shows that centroids for treatments supplying N levels above this threshold lie above the value on axis 1 that corresponds to the centroid for the MG3b NVC community, whereas all other treatments lie below this level. Seen in this light, the continued application of 12 t FYM ha-1 year-1 may have to be reviewed after a longer period of monitoring. By contrast, equivalent levels of inorganic fertilizer appeared to be less damaging and it may well be feasible to use levels of inorganic fertilizers supplying equivalent levels or higher of N, P and K at such sites. Here too, however, final judgement should be reserved until further monitoring has been completed, including parallel studies at Raisbeck and Pentwyn investigating the influence of FYM and equivalent inorganic treatments on soil microbial populations (R.D. Bardgett, unpublished data). The relatively few treatment effects shown at Fassagh 1, the generally high levels of variation in the data for that site, and overall shifts in plant community composition make the definition of sustainable fertilizer practice there difficult. As at Raisbeck, the evidence suggests that the high rate of annual FYM application is excessive, and also that inorganic fertilizers may be less damaging than equivalent FYM treatments. In view of the comparatively high levels of soil fertility at the site, presumably resulting from a recent history of moderate fertilizer application, and in view of the relatively low levels of species-richness, it would seem sensible to restrict input levels to the equivalent of 6-12 t FYM ha-1, preferably towards the lower end of this range, or to intermittent applications of moderate levels of FYM. There was marginal evidence (mainly in terms of reduced competitor score) to suggest that use of lime application was also beneficial at the site and the results of ordination modelling provide some support for these conclusions, also suggesting that use of lime without FYM may be preferable (R.A. Sanderson, unpublished data). It is difficult to assess how far these broad recommendations might apply to other sites without better information on the

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extent of grasslands in Northern Ireland supporting similar plant communities with comparable levels of soil fertility and pH. At Pentwyn, the high rate of FYM applied annually appears to have been excessive, as indicated by the effect on species-richness. Increases in legume content at intermediate levels of nutrient input, including 12 t FYM ha-1 applied annually in conjunction with liming, reflect the initial low soil fertility and pH. However, temporal trends in species-richness and in the abundance of MG5 positive indicator species were slight at this site and further monitoring to give a longer time perspective is needed before it can be determined whether moderate levels of fertilizer input, with or without lime, might be sustainable or even beneficial.

IMPLICATIONS FOR THE RESTORATION OF SPECIES-DIVERSITY TO IMPROVED GRASSLAND

At Gaisgill, response to fertilizers and lime were dominated by high soil fertility (particularly P) and low pH. Simple cessation of fertilizer inputs resulted in the greatest recovery in species-richness. Low inputs of FYM , e.g. at 6 t ha-1 annually or at twice that rate intermittently, appear to be sustainable, although Ellenberg fertility indices suggested differences even between these treatments and nil input control plots. As discussed earlier, lime alone appeared to increase nutrient availability and reduce vegetation quality as indicated by reduced stress-tolerator scores and increased fertility indices, although, when applied without FYM, lime increased herb content. Thus, applying lime alone is probably the best approach to restoring more diverse plant communities in the longer term, probably also providing some agronomic benefits in the shorter term by maintaining higher levels of productivity than cessation of all inputs. One might expect to draw similar conclusions for Fassagh 2, since soil P and K levels were high here and pH was low. The fact that there were few significant treatment effects probably reflects the high inter-replicate variation at the site compared to others that was also highlighted by ordination (R.A. Sanderson, unpublished data). There was sufficient evidence to suggest that, as at other sites, high rates of FYM or inorganic fertilizers are not sustainable, and that current inputs should be reduced. In contrast to other sites, herb content was reduced by liming, particularly in conjunction with annual FYM application. With the exception of Caltha palustris, which also declined on control plots, herb species declining on limed plots were not characteristic of the wetter conditions at the site and were not of particular ecological significance (e.g. Rumex species and Cerastium fontanum), so that this probably should not preclude liming at such sites. The results for Bush suggest that either intermittent fertiliser inputs or a moderate level of FYM applied annually to limed plots maintained species-richness at the site. However, ingress of MG5 positive indicators (mainly Rhinanthus minor) appeared to be restricted by FYM levels higher than 6 t ha-1 annually. Furthermore, as already noted, annual FYM at 12 t ha-1 applied annually to limed plots may have inhibited a desirable shift from MG5a/MG6b communities towards MG5b and c that occurred with other treatments. Despite the fact that species-richness did not improve with intermittent FYM at moderate rates applied to limed plots, this combination, or one including lower FYM rates applied annually, may be a more sustainable alternative. Of the three semi-improved sites, Bush almost certainly has the greater potential for restoration of vegetation quality within a reasonable time-scale compared to the other two sites, due to the higher initial species-richness and cover of MG5 positive indicators and its already closer similarity to valuable plant community types.

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However, as with other sites, further monitoring will be beneficial at all three sites since, even when seeds of desirable species are added artificially, restoration of such communities is a long-term process (Smith et al., 2003).

Acknowledgements

We would like to thank Helen Adamson, Roger Smith, John Fowbert, Jo Goodyear Melanie Flexen, Peter McEvoy, Maeve Dardis, Anna Gundrey, Ken Milner, Barry Wright, James Towers, and Anne Moon for carrying out botanical assessments, and Helen Adamson, Jo Goodyear, Gail Bennett and other staff from IGER, ADAS and Queen’s University Belfast for applying treatments. We would also like to thank Mike Burke and Alison Mole for data management. The project was funded by the Department for Environment, Food and Rural Affairs (formerly by MAFF), English Nature and the Countryside Council for Wales, to whom we are very grateful.

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Appendix. Frequency and mean % ground cover of plant species recorded at each site in May 1999 and 2004. Species are ordered in descending order of frequency within each site and year. Site 1 = Raisbeck, Site 2 = Gaisgill, Site 3 = Fassagh 1, Site 4 = Fassagh 2, Site 5 = Pentwyn and Site 6 = Bush. Species in bold are positive indicator species (MG3 for Sites 1 and 2, MG5 for the remainder).

1999 2004% of Mean % of Mean

Site Species quadrats %cover Species quadrats %cover

1 Holcus lanatus 100.0 16.79 Anthoxanthum odoratum 100.0 17.651 Festuca rubra 100.0 15.04 Plantago lanceolata 100.0 17.471 Plantago lanceolata 100.0 13.88 Ranunculus acris 100.0 13.271 Anthoxanthum odoratum 100.0 12.19 Leontodon hispidus 100.0 13.071 Trifolium pratense 100.0 9.25 Holcus lanatus 100.0 12.811 Leontodon hispidus 100.0 6.47 Festuca rubra 99.3 17.081 Ranunculus bulbosus 100.0 5.90 Dactylis glomerata 98.5 3.721 Agrostis capillaris 99.3 8.64 Rumex acetosa 98.5 1.501 Dactylis glomerata 99.3 4.09 Trifolium pratense 97.8 5.991 Conopodium majus 98.5 8.13 Rhinanthus minor 97.8 0.961 Rumex acetosa 98.5 4.09 Conopodium majus 97.0 25.591 Ranunculus acris 97.8 4.41 Ranunculus bulbosus 88.9 1.601 Trifolium repens 97.8 4.38 Trifolium repens 88.1 2.151 Bryophyte spp. 97.8 1.43 Cardamine pratensis 87.4 0.551 Luzula campestris 91.9 0.91 Luzula campestris 80.7 0.761 Leucanthemum vulgare 85.2 0.51 Alchemilla glabra 75.6 2.011 Taraxacum officinale agg. 82.2 1.35 Heracleum sphondylium 74.1 2.121 Cynosurus cristatus 80.7 3.73 Leucanthemum vulgare 70.4 0.691 Alchemilla glabra 74.1 0.92 Euphrasia officinalis agg. 69.6 0.441 Poa trivialis 73.3 2.90 Agrostis capillaris 66.7 1.621 Heracleum sphondylium 64.4 1.37 Bromus hordeaceus 63.7 1.411 Centaurea nigra 52.6 0.70 Lathyrus pratensis 63.0 0.501 Veronica chamaedrys 52.6 0.20 Centaurea nigra 60.7 3.211 Cardamine sp. 52.6 0.14 Cerastium fontanum 57.0 0.351 Euphrasia officinalis agg. 47.4 0.18 Geranium sylvaticum 54.8 5.151 Geranium sylvaticum 45.9 2.77 Prunella vulgaris 54.1 0.291 Bellis perennis 45.9 0.34 Taraxacum officinale agg. 51.1 0.271 Avenula pubescens 45.2 0.20 Cynosurus cristatus 46.7 0.361 Cerastium fontanum 45.2 0.06 Brachythecium rutabulum 43.7 0.321 Prunella vulgaris 33.3 0.05 Avenula pubescens 42.2 0.181 Rhinanthus minor 31.9 0.04 Poa trivialis 40.7 1.331 Bromus hordeaceus 31.1 0.20 Eurhynchium praelongum 40.0 0.311 Myosotis discolor 28.1 0.06 Veronica chamaedrys 38.5 0.141 Trisetum flavescens 27.4 0.13 Trisetum flavescens 26.7 0.081 Lathyrus pratensis 22.2 0.03 Listera ovata 23.0 0.111 Sanguisorba officinalis 21.5 0.29 Sanguisorba officinalis 21.5 0.991 Festuca pratensis 16.3 0.08 Vicia sepium 11.1 0.131 Lolium perenne 14.8 0.17 Primula veris 9.6 0.051 Listera ovata 13.3 0.01 Bellis perennis 8.1 0.021 Primula veris 12.6 0.03 Lolium perenne 5.9 0.031 Vicia sepium 3.7 0.01 Myosotis discolor 5.2 0.011 Achillea millefolium 3.7 0.01 Mnium hornum 3.0 0.011 Phleum pratense 3.7 0.01 Achillea millefolium 2.2 0.671 Filipendula ulmaria 1.5 0.04 Filipendula ulmaria 2.2 0.321 Lotus corniculatus 0.7 0.01 Botrychium lunaria 2.2 0.01

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1 Poa subcaerulea 0.7 <0.01 Ophioglossum vulgatum 1.5 0.021 Carex sp. 0.7 <0.01 Anthriscus sylvestris 1.5 0.011 Poa pratensis 0.7 <0.01 Calliergon cuspidatum 1.5 0.011 Anthriscus sylvestris 0.7 <0.01 Lotus corniculatus 0.7 0.011 Trollius europaeus 0.7 <0.01 Rhytidiadelphus squarrosus 0.7 <0.011 Phleum pratense 0.7 <0.01

Number of species/site: 50 51

2 Holcus lanatus 100.0 37.11 Holcus lanatus 100.0 40.892 Poa trivialis 100.0 22.06 Anthoxanthum odoratum 100.0 22.382 Agrostis capillaris 100.0 20.60 Ranunculus acris 99.4 19.972 Rumex acetosa 99.4 5.58 Rumex acetosa 99.4 6.082 Ranunculus acris 98.8 3.82 Agrostis capillaris 91.8 8.182 Lolium perenne 97.7 7.68 Cerastium fontanum 91.8 0.702 Anthoxanthum odoratum 95.3 6.53 Ranunculus repens 90.6 5.032 Alopecurus pratensis 86.5 2.65 Lolium perenne 88.9 4.312 Ranunculus repens 86.0 3.03 Taraxacum officinale agg. 87.1 2.642 Cardamine sp. 70.2 0.27 Bellis perennis 84.2 3.622 Taraxacum officinale agg. 62.6 0.48 Eurhynchium praelongum 82.5 2.362 Bryophyte spp. 62.0 0.35 Poa trivialis 80.7 5.412 Bellis perennis 43.3 0.44 Alopecurus pratensis 77.8 1.972 Cerastium fontanum 43.3 0.18 Brachythecium rutabulum 54.4 0.612 Montia fontana 42.1 0.21 Trifolium repens 46.2 6.612 Trifolium repens 38.6 1.42 Cardamine sp. 45.0 0.172 Rumex obtusifolius 31.0 1.63 Veronica serpyllifolia 40.9 0.212 Veronica serpyllifolia 7.0 0.03 Cardamine pratensis 30.4 0.122 Plantago lanceolata 6.4 0.02 Rumex obtusifolius 26.3 1.432 Sanguisorba officinalis 5.8 0.01 Plantago lanceolata 14.0 0.152 Anthriscus sylvestris 3.5 0.01 Cynosurus cristatus 11.1 0.342 Ranunculus ficaria 2.3 0.01 Vicia cracca 8.2 0.142 Achillea millefolium 2.3 0.01 Lathyrus pratensis 7.0 0.102 Vicia cracca 2.3 <0.01 Sanguisorba officinalis 7.0 0.052 Lathyrus pratensis 2.3 <0.01 Cardamine hirsuta 7.0 0.022 Conopodium majus 1.8 <0.01 Montia fontana 5.8 0.012 Vicia sepium 1.2 <0.01 Vicia sepium 5.3 0.202 Dactylis glomerata 1.2 <0.01 Alchemilla glabra 5.3 0.042 Rumex crispus 0.6 0.01 Anthriscus sylvestris 4.7 0.032 Agrostis stolonifera 0.6 <0.01 Dactylis glomerata 2.9 0.032 Festuca pratensis 0.6 <0.01 Poa pratensis 1.8 0.052 Leontodon hispidus 0.6 <0.01 Ranunculus ficaria 1.8 0.022 Sanguisorba minor 0.6 <0.01 Leontodon autumnalis 1.8 0.012 Stellaria media 0.6 <0.01 Veronica chamaedrys 1.8 0.012 Alchemilla glabra 0.6 <0.01 Luzula campestris 1.8 <0.012 Phleum pratense 1.8 <0.012 Bromus hordeaceus 1.8 <0.012 Trifolium pratense 1.2 0.012 Cirsium vulgare 1.2 0.012 Rhytidiadelphus squarrosus 1.2 <0.012 Conopodium majus 1.2 <0.012 Trisetum flavescens 0.6 0.022 Rumex crispus 0.6 0.01

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2 Heracleum sphondylium 0.6 <0.012 Achillea ptarmica 0.6 <0.012 Festuca rubra 0.6 <0.012 Crataegus monogyna 0.6 <0.01


3 Juncus acutiflorus 100.0 20.62 Anthoxanthum odoratum 99.3 16.053 Bryophyte spp. 99.3 19.71 Holcus lanatus 98.5 16.943 Anthoxanthum odoratum 97.0 6.04 Juncus acutiflorus 98.5 15.833 Holcus lanatus 94.1 5.16 Trifolium repens 95.6 18.733 Carex nigra 89.6 3.79 Rhytidiadelphus squarrosus 91.1 15.063 Ranunculus acris 88.9 4.46 Ranunculus acris 83.0 4.783 Trifolium repens 80.7 6.50 Cynosurus cristatus 80.0 4.773 Cynosurus cristatus 80.7 2.59 Agrostis canina 76.3 9.093 Ranunculus repens 76.3 3.47 Trifolium pratense 75.6 8.233 Juncus effusus 68.1 5.95 Juncus conglomeratus 71.1 6.433 Festuca rubra 68.1 1.93 Festuca rubra 67.4 2.943 Agrostis canina 64.4 3.47 Ranunculus repens 66.7 4.493 Agrostis capillaris 60.0 1.86 Luzula

campestris/multiflora63.7 0.80

3 Trifolium pratense 55.6 1.56 Carex nigra 59.3 0.993 Poa trivialis 51.1 1.03 Hypochoeris radicata 54.1 3.043 Carex ovalis 48.9 1.59 Lychnis flos-cuculi 46.7 1.073 Lathyrus pratensis 45.9 0.94 Poa trivialis 40.7 0.723 Hieracium pilosella 43.0 1.53 Juncus effusus 39.3 4.583 Cardamine pratensis 42.2 0.64 Rumex acetosa 37.0 0.743 Rumex acetosa 37.8 0.53 Calliergon cuspidatum 30.4 2.403 Festuca ovina 33.3 0.64 Agrostis capillaris 30.4 1.103 Ajuga reptans 32.6 0.71 Filipendula ulmaria 28.1 1.803 Agrostis stolonifera 31.9 0.69 Ajuga reptans 17.8 0.373 Bellis perennis 31.9 0.58 Plantago lanceolata 14.8 0.323 Filipendula ulmaria 31.1 3.56 Agrostis stolonifera 13.3 0.733 Alopecurus pratensis 30.4 1.03 Carex ovalis 11.9 0.093 Lolium perenne 25.9 0.46 Cerastium fontanum 11.9 0.093 Prunella vulgaris 25.9 0.39 Lathyrus pratensis 11.1 0.263 Luzula campestris 23.7 0.36 Vicia cracca 10.4 0.353 Lychnis flos-cuculi 20.7 0.30 Peltigera sp. 9.6 0.553 Plantago lanceolata 19.3 0.32 Prunella vulgaris 8.9 0.103 Carex flacca 17.0 0.41 Phleum pratense 8.1 0.143 Carex panicea 15.6 0.32 Lolium perenne 8.1 0.053 Vicia cracca 11.9 0.29 Succisa pratensis 7.4 0.673 Ranunculus flammula 8.9 0.13 Bellis perennis 6.7 0.113 Phleum pratense 7.4 0.22 Carex panicea 5.9 0.043 Knautia arvensis 6.7 0.22 Potentilla erecta 4.4 0.043 Myosotis arvensis 6.7 0.09 Eurhynchium praelongum 3.7 0.163 Cirsium dissectum 5.2 0.18 Brachythecium rutabulum 3.7 0.103 Equisetum palustre 5.2 0.06 Myosotis discolor 3.0 0.013 Festuca pratensis 3.7 0.09 Stellaria alsine 2.2 0.193 Poa pratensis 3.7 0.09 Festuca pratensis 2.2 0.153 Potentilla erecta 3.0 0.04 Cirsium dissectum 2.2 0.093 Cerastium fontanum 3.0 0.03 Ranunculus flammula 2.2 0.02

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3 Taraxacum officinale agg. 2.2 0.03 Equisetum palustre 2.2 0.013 Carex demissa 2.2 0.02 Lophocolea bidentata 2.2 0.013 Peltigera sp. 2.2 0.02 Nardus stricta 2.2 0.013 Nardus stricta 1.5 0.02 Climacium dendroides 2.2 0.013 Centaurea nigra 1.5 0.02 Glyceria fluitans 1.5 0.023 Lolium multiflorum 1.5 0.02 Trifolium dubium 1.5 0.013 Alopecurus geniculatus 1.5 0.01 Cardamine pratensis 1.5 0.013 Dactylis glomerata 0.7 0.01 Galium palustre 1.5 0.013 Acer pseudoplatanus 0.7 0.01 Taraxacum officinale agg. 1.5 0.013 Carex echinata 0.7 0.013 Cirsium palustre 0.7 0.013 Plagiomnium undulatum 0.7 0.013 Bromus sp. 0.7 <0.013 Epilobium parviflorum 0.7 <0.013 Epilobium sp. 0.7 <0.01


4 Agrostis stolonifera 100.0 48.67 Holcus lanatus 100.0 22.534 Ranunculus repens 99.3 15.13 Ranunculus repens 96.3 10.184 Holcus lanatus 99.3 11.93 Cynosurus cristatus 91.9 8.844 Agrostis capillaris 94.1 5.59 Trifolium repens 85.9 16.604 Poa trivialis 83.7 4.89 Anthoxanthum odoratum 82.2 5.684 Ranunculus acris 80.7 2.13 Bellis perennis 76.3 4.324 Lolium perenne 75.6 2.92 Cerastium fontanum 72.6 1.054 Bryophyte spp. 64.4 1.61 Lolium perenne 65.9 5.064 Rumex acetosa 63.7 1.64 Poa trivialis 63.0 3.934 Cardamine pratensis 61.5 0.87 Trifolium pratense 60.7 4.034 Anthoxanthum odoratum 56.3 1.21 Rumex acetosa 59.3 1.024 Juncus acutiflorus 55.6 5.36 Juncus acutiflorus 54.1 11.414 Cerastium fontanum 53.3 1.70 Ranunculus acris 54.1 1.694 Alopecurus pratensis 35.6 1.44 Agrostis stolonifera 43.7 3.794 Trifolium repens 34.8 0.97 Plantago lanceolata 43.0 4.084 Juncus effusus 31.9 1.99 Alopecurus pratensis 38.5 2.244 Phleum pratense 28.9 1.13 Juncus effusus 37.8 3.724 Filipendula ulmaria 28.9 0.70 Myosotis discolor 37.8 0.204 Bellis perennis 28.1 0.40 Taraxacum officinale agg. 36.3 1.334 Rumex obtusifolius 24.4 1.48 Festuca rubra 35.6 2.054 Caltha palustris 23.7 1.28 Trifolium dubium 28.1 1.564 Alopecurus geniculatus 22.2 0.88 Rhytidiadelphus squarrosus 21.5 1.384 Cynosurus cristatus 22.2 0.34 Agrostis capillaris 21.5 1.274 Festuca pratensis 21.5 0.49 Caltha palustris 19.3 1.284 Plantago lanceolata 18.5 0.67 Rumex obtusifolius 17.8 0.794 Trifolium pratense 13.3 0.34 Filipendula ulmaria 16.3 0.314 Taraxacum officinale agg. 12.6 0.16 Brachythecium rutabulum 14.8 0.204 Myosotis arvensis 11.9 0.13 Vicia cracca 13.3 0.504 Festuca rubra 8.9 0.19 Lychnis flos-cuculi 12.6 0.074 Carex ovalis 7.4 0.17 Calliergon cuspidatum 9.6 0.654 Dactylis glomerata 5.9 0.19 Prunella vulgaris 8.9 0.224 Vicia cracca 5.9 0.14 Juncus conglomeratus 6.7 0.284 Vicia sp. 5.2 0.08 Cardamine pratensis 6.7 0.044 Lathyrus pratensis 5.2 0.07 Bromus sp. 5.9 0.11

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4 Lychnis flos-cuculi 4.4 0.06 Phleum pratense 5.9 0.114 Ranunculus flammula 3.0 0.03 Agrostis canina 4.4 0.204 Juncus

articulatus/acutiflorus2.2 0.09 Festuca pratensis 4.4 0.17

4 Carex elongata 2.2 0.07 Lathyrus pratensis 3.7 0.074 Ajuga reptans 2.2 0.06 Eurhynchium praelongum 3.7 0.054 Carex flacca 0.7 0.06 Senecio aquaticus 3.0 0.084 Festuca ovina 0.7 0.04 Luzula

campestris/multiflora3.0 0.02

4 Deschampsia cespitosa 0.7 0.02 Carex nigra 3.0 0.014 Agrostis canina 0.7 0.01 Leontodon autumnalis 2.2 0.034 Centaurea nigra 0.7 0.01 Myosotis arvensis 2.2 0.014 Galium palustre 0.7 0.01 Centaurea nigra 1.5 0.044 Carex nigra 0.7 0.01 Plagiomnium undulatum 1.5 0.034 Carex rostrata 0.7 0.01 Hypochoeris radicata 1.5 0.014 Hieracium pilosella 0.7 0.01 Ajuga reptans 1.5 0.014 Prunella vulgaris 0.7 0.01 Potentilla erecta 0.7 0.014 Lolium multiflorum 0.7 0.01 Dactylis glomerata 0.7 0.014 Taraxacum palustre agg. 0.7 0.01 Equisetum palustre 0.7 0.014 Achillea ptarmica 0.7 <0.014 Carex hirta 0.7 <0.014 Cirsium vulgare 0.7 <0.014 Veronica montana 0.7 <0.014 Veronica serpyllifolia 0.7 <0.01


5 Anthoxanthum odoratum 100.0 20.23 Festuca rubra 100.0 46.975 Centaurea nigra 100.0 20.13 Centaurea nigra 100.0 22.325 Plantago lanceolata 100.0 6.14 Anthoxanthum odoratum 100.0 19.245 Trifolium pratense 100.0 5.18 Trifolium pratense 97.7 7.585 Festuca rubra 99.4 26.36 Plantago lanceolata 96.5 7.655 Holcus lanatus 98.8 4.74 Luzula campestris 96.5 1.905 Rhinanthus minor 97.1 6.84 Ranunculus bulbosus 93.6 6.505 Ranunculus bulbosus 97.1 5.00 Leontodon hispidus 91.8 3.655 Luzula campestris 96.5 1.13 Rhinanthus minor 90.1 2.335 Leontodon hispidus 95.9 10.11 Lotus corniculatus 87.1 3.835 Lotus corniculatus 95.3 12.88 Bryophyte spp. 86.0 4.315 Agrostis capillaris 94.2 9.95 Holcus lanatus 83.6 3.865 Leucanthemum vulgare 89.5 1.51 Trifolium repens 82.5 5.965 Bryophyte spp. 86.0 1.49 Leucanthemum vulgare 80.7 1.185 Hypochoeris radicata 84.2 2.98 Cerastium fontanum 63.2 0.285 Taraxacum officinale agg. 83.0 1.21 Taraxacum officinale agg. 56.1 0.375 Ranunculus acris 81.9 1.37 Achillea millefolium 54.4 0.245 Trifolium repens 77.8 0.88 Hypochoeris radicata 51.5 0.725 Achillea millefolium 77.2 0.80 Ranunculus acris 51.5 0.555 Cynosurus cristatus 71.3 2.07 Agrostis capillaris 49.7 1.175 Leontodon autumnalis 66.1 0.71 Dactylorhiza fuchsii 49.1 0.725 Prunella vulgaris 45.0 0.39 Cynosurus cristatus 43.9 0.565 Rumex acetosa 31.0 0.25 Lathyrus pratensis 39.2 0.265 Crepis capillaris 28.1 0.18 Rumex acetosa 33.3 0.335 Lathyrus pratensis 28.1 0.12 Orchis morio 31.0 0.43

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5 Dactylorhiza fuchsii 26.9 0.43 Polygala vulgaris 31.0 0.155 Cerastium fontanum 25.7 0.07 Leontodon autumnalis 29.2 0.095 Polygala vulgaris 24.6 0.05 Fraxinus excelsior 29.2 0.035 Fraxinus excelsior 19.3 0.03 Prunella vulgaris 25.1 0.105 Dactylis glomerata 9.9 0.14 Poa trivialis 17.0 0.795 Orchis morio 9.4 0.10 Dactylis glomerata 12.9 0.155 Stellaria graminea 6.4 0.01 Acer pseudoplatanus 11.7 0.025 Crataegus monogyna 5.8 0.01 Veronica chamaedrys 8.2 0.135 Veronica chamaedrys 5.3 0.06 Stellaria graminea 7.0 0.115 Heracleum sphondylium 2.9 0.02 Heracleum sphondylium 4.7 0.075 Ajuga reptans 1.8 0.04 Crepis capillaris 4.1 0.015 Vicia cracca 1.8 0.02 Ranunculus repens 3.5 0.095 Acer pseudoplatanus 1.8 0.01 Conopodium majus 3.5 0.015 Myosotis discolor 1.2 <0.01 Ajuga reptans 2.9 0.035 Conopodium majus 0.6 0.01 Platanthera chlorantha 2.9 0.015 Senecio jacobaea 0.6 0.01 Crataegus monogyna 2.9 <0.015 Hyacinthoides non-scripta 0.6 <0.01 Trifolium dubium 2.3 0.015 Platanthera chlorantha 0.6 <0.01 Bromus hordeaceus 1.8 0.025 Ophioglossum vulgatum 0.6 <0.01 Hyacinthoides non-scripta 1.8 0.015 Lolium perenne 0.6 <0.01 Vicia cracca 1.2 0.015 Galium aparine 0.6 <0.01 Veronica serpyllifolia 1.2 0.015 Trifolium dubium 0.6 <0.01 Acer campestre 1.2 <0.015 Vicia sativa ssp. nigra 0.6 <0.01 Lolium perenne 1.2 <0.015 Primula veris 0.6 0.015 Anthriscus sylvestris 0.6 <0.015 Primula vulgaris 0.6 <0.01


6 Anthoxanthum odoratum 100.0 23.79 Festuca rubra 100.0 53.226 Holcus lanatus 100.0 11.67 Ranunculus bulbosus 100.0 10.936 Ranunculus bulbosus 99.4 6.37 Anthoxanthum odoratum 98.2 20.596 Festuca rubra 98.8 30.28 Trifolium repens 98.2 10.506 Agrostis capillaris 98.8 22.63 Agrostis capillaris 97.1 16.166 Rumex acetosa 97.1 5.91 Rumex acetosa 95.9 3.966 Cynosurus cristatus 97.1 5.87 Luzula campestris 86.5 3.746 Trifolium repens 96.5 8.31 Holcus lanatus 85.4 3.646 Ranunculus acris 95.3 6.13 Rhinanthus minor 73.1 4.496 Lolium perenne 93.6 3.60 Lotus corniculatus 58.5 7.366 Taraxacum officinale agg. 89.5 2.79 Bryophyte spp. 56.7 1.166 Luzula campestris 87.1 3.54 Ranunculus acris 53.8 0.696 Trifolium pratense 76.0 2.89 Cerastium fontanum 52.6 0.456 Bryophyte spp. 66.1 0.34 Lolium perenne 50.3 4.906 Hypochoeris radicata 63.7 1.49 Trifolium pratense 50.3 0.966 Cirsium arvense 59.6 1.77 Taraxacum officinale agg. 50.3 0.566 Poa trivialis 59.6 1.53 Dactylis glomerata 42.1 1.346 Cerastium fontanum 55.6 0.28 Plantago lanceolata 34.5 2.086 Lotus corniculatus 46.2 4.58 Hypochoeris radicata 33.3 0.486 Dactylis glomerata 36.8 0.55 Poa trivialis 31.0 1.716 Plantago lanceolata 25.1 0.50 Cynosurus cristatus 26.3 0.176 Crepis capillaris 19.9 0.25 Cirsium arvense 16.4 0.286 Ranunculus repens 17.5 0.26 Acer pseudoplatanus 14.6 0.04

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6 Prunella vulgaris 14.0 0.07 Crepis capillaris 9.4 0.056 Leontodon autumnalis 8.8 0.10 Lathyrus pratensis 7.6 0.046 Bromus hordeaceus 8.2 0.03 Prunella vulgaris 7.0 0.036 Bellis perennis 7.0 0.02 Stellaria graminea 5.8 0.076 Centaurea nigra 5.8 0.13 Leontodon hispidus 5.3 0.076 Trifolium dubium 5.3 0.02 Centaurea nigra 5.3 0.066 Rhinanthus minor 4.7 0.07 Bromus hordeaceus 5.3 0.016 Stellaria graminea 4.1 0.06 Heracleum sphondylium 4.1 0.036 Conopodium majus 4.1 0.02 Listera ovata 3.5 0.186 Lathyrus pratensis 2.9 0.09 Ranunculus repens 2.9 0.116 Leontodon hispidus 2.9 0.05 Fraxinus excelsior 2.9 <0.016 Heracleum sphondylium 2.3 0.07 Quercus sp. 2.3 <0.016 Veronica serpyllifolia 1.8 <0.01 Urtica dioica 1.8 0.076 Phleum pratense 1.2 <0.01 Conopodium majus 1.8 0.026 Arrhenatherum elatius 0.6 0.01 Ranunculus ficaria 1.8 0.016 Achillea millefolium 0.6 0.01 Dactylorhiza fuchsii 1.8 <0.016 Leucanthemum vulgare 0.6 <0.01 Vicia cracca 1.2 0.056 Vicia cracca 0.6 <0.01 Tragopogon pratensis 1.2 0.036 Leontodon autumnalis 1.2 0.016 Phleum pratense 1.2 <0.016 Acer campestre 1.2 <0.016 Achillea millefolium 1.2 <0.016 Arrhenatherum elatius 0.6 0.036 Hyacinthoides non-scripta 0.6 0.016 Leucanthemum vulgare 0.6 <0.016 Trifolium dubium 0.6 <0.016 Veronica chamaedrys 0.6 <0.01


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The effects of organic and inorganic fertilizers on the...

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