IRRIGATION SUSTAINABILITY IN THE LAND USE/SOIL SYSTEM IN SOUTH ITALY: RESULTS FROM A GIS SEMPLIFIED APPROACH AND

FUTURE METHODOLOGICAL DEVELOPMENTS

Andrea Fais1, Rosario Napoli2, Pasquale Nino1, Paolo Bazzoffi2, Nicola Laruccia3

National Council For Research in Agriculture

Soil Study and Conservation Institute Florence

National Institute of Agricultural EconomicsRome

INTRODUCTION

•Irrigated agricultural productions about 72 % of total agriculture’s GDP Southern Italy Regions.•The total area covered by irrigated crops is about 1.600.000 hectares (60 % of the total water consumption). •Water networks and irrigation utilities have a low degree of efficiency, with significant losses of water (differences between sources water availability and water availability in irrigation areas) from sources to field. The full utilisation of the available water means the possibility of reducing the environmental impact of water use. •The evaluation of water volumes needs very detailed information on land use, Crop Water Requirements per crop, Irrigation techniques, and Water costs.•The EU has financed, inside Reg. (CEE) n. 2081/93 – QCS 1994/99, the Operative Programme (P.O.) “Water Resource, in Objective 1 Italian Regions”. This project was finalised to the realisation of a geographic information system for water resources management in agriculture (SIGRIA). INEA has collected data on irrigation infrastructure and on crop water requirements in all the Southern Italy Regions Land Reclamation and irrigation Consortium (Italian administrative structure for irrigation water management). The following information are available thanks to this P.O.:•Land use map CASI 3 (1:50.000 scale, and 4th level CORINE Land Cover nomenclature);•Land Reclamation and irrigation Consortium irrigated areas and waterworks maps;•Nominal crop water requirements (N CWR): the volumes value used in the irrigation Consortia to define the water cost (tariff €/ha);•Real crop water requirements (R CWR). The R CWR is based on the calculation of effective water volumes, utilising a SWAP implemented application, that has been validated on 5 Consortia test sites;•The information about irrigation techniques (Sprinkler - Drop – Flowing)

STUDY AREA

The work covers all the irrigated areas of (EU) Objective 1 Italian Regions (Figure 1). Data were

collected and organised at “Land Reclamation and

irrigation Consortium” and regional (NUTS II) level.

In South Italy

66 “Consortia”

manage an area of

8.358.165 hectares

IRRIGATED AREAS IDENTIFICATION: ADMINISTRATIVE BOUNDARIES

Land Reclamation and irrigation Consortium are organised in two principal administrative and physical-territorial units: Comprensori and distretti (in the picture). The boundaries of this administrative and physical-territorial units have been acquired throw direct inquire beside the Land Reclamation and irrigation Consortium

Capitanata Consortium boundaries (Puglia

Region)

IRRIGATED CROP GEOREFERENCED DATABASE – 1.LAND USE MAP

Different alphanumeric data (administrative and statistics information) on crop surfaces were integrated, using G.I.S. procedures, with CASI 3 cartographic data (land use classes/polygons), inside administrative aggregations (municipalities, administrative irrigated areas).

CORINE code

Land use code

Description

211 211 Not irrigated arable land

212

2121 Irrigated industrial crops - spring – summer cycle

2122 Irrigated Horticulture at summer - autumn - spring cycle

2123 Irrigated Horticulture at spring – summer cycle

2124 Nurseries

2125 Greenhouses

213 213 Rice field

2212211 Irrigated vineyards

2212 Not Irrigated vineyards

222

2221 Irrigated fruit and berries plantation

2222 Not Irrigated fruit and berries plantation

223

2231 Irrigated olives groves

2232 Not Irrigated olives groves

231231 Irrigated pastures

232 Not Irrigated pastures

IRRIGATED CROP GEOREFERENCED DATABASE – NOMINAL CROP WATER REQUIREMENT MAP

Crop evapotranspiration (ETc) calculation is based on the following FAO two step approach:1.Reference evapotranspiration (Eto) computing;2.Crop coefficient (Kc) application, that take into account the differences in the crop canopy and aerodynamic resistance relative to the hypothetical reference crop. cc KEToET The final value refers to each land use polygon taking into account the irrigation techniques. It represents the Nominal Water Volumes to use per each map unit.

ID Polygon

CASI 3 code

Data base code

Description He Polygon

% He crop

1 2121

21211 Sugar beet

5060 30

21213 Maize 40 20

2 2122

21221 artichoke

70

43 30

21222 cauliflower 7 5

21223 salad 21 15

21224 potato 29 20

3 2123

21231 tomatoes

86

17 15

21232 aubergine 9 8

21233 water melon

15 13

21234 melon 12 10

21235 asparagus 47 40

IRRIGATED CROP GEOREFERENCED DATABASE – IRRIGATION TECNIQUES

1. Information available on 275.617 he (circa 70% of the irrigated surface). The main irrigation techniques are: - Sprinkler 58,9%; - Drop 27,2%; - Flowing 8,90%

2. In the actual dynamic, the abandon of flowing and the constant decrement of the sprinkler techniques are both in favour of the drop system, especially on the irrigated orchards. This process tends to reduce the utilised volumes per ha, incrementing the on farm irrigation investment. But it actually seems to not produce any results on the water costs.

3. The Nominal CWR (Ncwr) doesn’t take into account the differences between the irrigation techniques inside a single irrigated land use.

Irrigation techniques (he)

Region Flowing Submersion Infiltration Sprinkler Drop Total Region

Campania 66 65 5.514 7.115 362 13.122

Puglia 506 0 0 37.944 16.920 55.370

Sicilia 3.645 200 500 11.407 25.703 41.475

Sardegna 20 4.118 23 39.731 15.637 59.529

Calabria 1.993 730 0 6.902 681 10.306

Abruzzo 15.551 11 0 44.215 89 59.866

Molise 0 0 0 1.615 311 1.925

Basilicata 2.735 0 2.527 13.532 15.230 34.024

Total 24.516 5.124 8.564 162.461 74.932 275.617

IRRIGATION INFRASTRUCTURE INVESTMENTS AND WATER COSTS Data on water costs (as well as the information related to irrigation networks, and related

areas, nominal CWR and irrigation techniques) has been collected on the 66 Consortia (Land Reclamation and irrigation) surveys, based on the Q2 SIGRIA questionnaire. Data are

up-dated till 1997.The efficiency of the irrigation infrastructure investments is based on the ratio between areas equipped with irrigation waterworks and irrigated areas (from 26 to 81 %). This significant difference is mainly due to a structural insufficient water availability to irrigate all the equipped area. In second order, 20-25 % of this difference is due to the normal rotation/crop shifts inside a Comprensorio. In some cases the irrigated areas is larger then the equipped one. This is principally due to the private underground water utilisation. The unitary cost of the irrigation infrastructures is used to quantify the efficiency of the investments analyse.

0

20.000

40.000

60.000

80.000

100.000

120.000

140.000

160.000

180.000

200.000

Abruzzo

Basilicata

Calabria

Campania

Molise

PugliaSardegna

Sicilia

EQUIPPED AREA (HA)

IRRIGATED AREA (HA)

Irrigation Infrastructures Investments (III) = average cost hectare/year of both public (IIIpub.: adduction and distribution pipelines, plus waterworks nodes) and private (IIIpriv.: rolls and sprinkler

– IIIs - or micro-irrigation tools - IIIi) investments at Italian level (yearly amortization cost = depreciation time: 30-40 years for pipelines; 12-15 for farm irrigation tools)IIIs = IIIpub/ha + IIIpriv. s = 400 €/ha + 397 €/ha = 797 €/haIIIi = IIIpub/ha + IIIpriv. i = 400 €/ha + 788 €/ha = 1.188 €/ha

Water cost•The infrastructures investments, both public and private, concern not only the yearly irrigated area, but all the area equipped with pipelines, and consequently the on-farm field water distribution equipment. •It’s pretty clear that with the micro irrigation cost the farmer pays ad indirect additional water cost, without any tangible direct benefits (in most cases, it doesn’t correspond to a reduction of the tariff per hectare). Benefits that are instead completely for rural and urban communities, and environment, having this irrigation technique direct effects on water use savings.

Unitary Cos t € /m c per Cons ort ium

0,000

0,050

0,100

0,150

0,200

0,250

0,300

0,350

1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76

Co n so rz i

€_

mc

€_m c

SOILS DATABSE AND IRRIGATION SOIL SUITABILITY MAP - 1

The National Soil Database (from the ISSDS/CRA database) is the basis adopted to the irrigation suitability evaluation. The United States Bureau of Reclamation methodology, modified by the ISSDS during the project POM INEA in the southern regions (POM IRRIGAZIONE, 1998-2002), has been adopted for the evaluation procedure.The soil map units layer is comprehensive of:1.Soil Cartographic Unit Code, linked to a Soil Typological Unit in the SIGRIA soil database; 2.Irrigation suitability class codes, for the three major types of irrigation techniques (Drop, Sprinkler and Flowing/Submersion)3.Major limitation suffix, (e.g.: PE = slope, T = texture, D = drainage, etc.);4.Slope code class and related range of values.

Dro

p s

oil s

uita

bility

Sp

rinkle

r soil s

uita

bility

Several soil features and qualities taken into account to evaluate the irrigation suitability (surface and internal soil).•A matching table defines the type of limitation on the basis of the maximum limitation criteria (the strongest limitation determines the suitability class).•For the slope classes, adopted the main irrigation techniques (Drop, sprinkler and flowing) thresholds.

SOILS DATABASE AND IRRIGATION SOIL SUITABILITY MAP - 2Sprinkler soil suitability in NW Sardinia Island

Su

itab

le (S

1)

Not S

uita

ble

(N) M

od

. Su

itab

le (S

2)

LAND SUSTAINABILITY TO IRRIGATION PRACTICES AND EVALUATION OF REAL CROP WATER REQUIREMENTS

Starting from the FAO Land productivity index concept, the relationship between the productivity index and water volumes has been estimated,

based on the assumption that the overall agronomic efficiency of water use (Fag ) doesn’t change in the time.

•For each map unit with same soil, land use, and irrigation technique, the soil suitability reduction factors has been directly related to the nominal normalized water needs in the calculation of the real crop water requirement (Rcwr)•Applying the reduction factor to the optimal CWR, the lesser suitable is the soil the higher is the CWR value, we proposed the•Irrigation economical and technical Efficiency Index: Ieff = Rcwr/Nwcr •The Ieff represents the ratio between this two values The range may be variable from 1, that is the optimal situation, to 2.5, for the not suitable soils.

Values of Ieff for the Land Units of Italy Southern Regions

Soil suitability class for specified irrigation techniques

S1 – suitable

S2 – moderately suitable

S3 – marginally suitable

N – not suitable

IEff values 1.0 1.25 1.67 2.60

RESULTS - 1 The irrigation suitability of the soil of the South Italian Land Reclamation Consortia irrigated areas defined with the integration of related GIS layers.•The Ieff index, defining the efficiency of irrigation water use per crop/soil/irrigation technique, allows to calculate the extra amount of water/ha due to an inefficient water use in not suitable landscapes (Δ CWR mc/ha). •Value applied on the whole irrigated surface inside the Consortia equipped area to have the total extra water (Δ mc CWR) per Consortium and Region.

RESULTS - 2

•The data of the total Δ CWR in Southern Italian Region (425.228.118 mc) represents about the 34 % of the total CWR, more or less the same quota of the unitary value (1039,6 mc/ha).The Δ CWR is actually wastewater or waste money (about 22 M€, based on an average unitary irrigation water cost of 0,052/m3), but, with appropriate rural and agricultural policies it should be considered as saveable water for irrigated area expansion, or for other uses.

•Particularly attention has to be paid on the opportunity of expanding the irrigated areas already equipped with irrigation waterworks, but that are actually non irrigated for lack of water. Presently the ratio between areas equipped with irrigation waterworks and irrigated areas is very low in several Consortia (in table 10: Pipeline use % is about 50 % in the whole area).

•Considering the total Δ CWR as volumes utilisable to increase the irrigated area (G column), the total irrigated surface could rise to 553.228 hectares, with an average relative increase of 17, 6 %, and the yearly infrastructure investment could decrease to 1.181 €/year/ha.

CONCLUSIONS

The present work tries to give the baseline information to evaluate the efficiency in irrigation water use.

The IEff index allows to determine the additional water wasted in an irrigation area, on the basis of the

irrigation suitability of the land use/soil/irrigation technique system.

After a first analysis of the wastewater and infrastructures investment costs, two main considerations:

1.Farmers pay a unitary water cost that is generally far away from the real cost; this also considering that infrastructural investments are completely founded by the public, and are not included in water costs;

2.The low irrigation water cost compensates farm irrigation waterworks yearly costs, particularly significant for the drop systems;

3.The low water cost contributes to an inefficient agricultural water use; the perfect evaluation of the real/optimal crop water requirement will allow the farmer to pay water at least on the basis of the real volumes of irrigation, or to reduce the unitary water volumes.