EVALUATION OF EXPERIMENTAL METHODSAND PRACTICE IN PLANNING

FOR SOIL AND WATER CONSERVATION IN HUNGARY

Dr. B. ERÖDI, V. HORVATH and M. KAMARÀS (•)Institute for Hydraulic Planning, Budapest, Hungary

RÉSUMÉ

L'évaluation des tâches de la conservation du sol et des eaux est devenue unedes questions des plus essentielles du développement de l'agriculture Hongroise.Cette évaluation ne se limite pas à la définition de la perte du sol exclusivement.Elle embrasse également l'étude des conditions pédologiques et météorologiques desrégions nécessitant des mesures conservatrices ainsi que des conditions caractéris-tiques des pentes et celles de la cultivation agricole. Finalement elle s'étend sur l'étudedes mesures nécessaires agronomiques et techniques et de tout les coûts qui en dérivent.

Pour l'adaptation la plus économique des méthodes conservatrices les planifi-cateurs sont tenus d'examiner sur la base de l'expérience acquise en Hongrie età l'étranger — l'efficacté des méthodes particulière.

Ils échelonnent les mesures à des catégories de pentes selon leur adaptabilité.Avec les procédés agronomiques et techniques ils visent à limiter la perte du sol

annuelle moyenne causée par l'érosion à 15 t/ha sur les 4 millions ha-s menacés dedestruction.

Les planificateurs contrôlent l'efficacité des mesures prévues dans des plans desdifférents bassins versants par des calculs mathématiques spéciales.

ABSTRACT

The assessment of the targets of soil and water conservation became one of themost important tasks in the development of Hungarian agriculture. This assessmentwork not only determines erosion loss of the soil but also extends to pedological,meteorological, slope and cultivation conditions existing in different regions with therequired agronomical and technical organisatory tasks of soil conservation and theircosts. For most economical realization of soil conservation the planners examinethe efficiency of the individual methods on the grounds of experience made in Hun-gary and abroad and of actual experiments.

Practices, according to their applicability, are bound to so-called slope categoryranges.

Agronomical and technical soil conservation methods evaluated separately andby their joint effect are combined to allow an average of 15 t/ha/year soil loss on the4 million ha endangered by erosion.

Soil conservation system of drainage basins as established in the plans (individualpractices) are controlled for efficiency optimum with the own mathematical methodof the authors.

1. INTRODUCTION

About 45 per cent of the total agricultural area of Hungary, around 4 million ha,is mountainous and hilly country. Since 1960 practically the whole agricultural areahas been cultivated in large-scale farms. Until this date the initiation of soil conser-vation had been hindered largely by the sloping plots of small forms. To-day, on theother hand, with increasing mechanization of large-scale farms, the introduction ofsoil conservation farming became an urgent necessity.

In conformity with the increasing rate of the development of agriculture and ofits reorganization it is more and more important to establish the rate of soil lossesand targets for soil conservation.

(*) The authors are working at the section for soil conservation planning at theInstitute for Hydraulic Planning, Hungary, Budapest, V. Nador utca 36.

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Although experiments and soil conservation works have been conducted since1950 it can not be contended that the desirable level has been reached either in experi-mental work or in collecting of experience. Therefore beyond evaluation of resultsobtained in Hungary also experimental experience and practical observations made inforeign countries should be duly utilized.

2. EFFECT OF PHYSICAL CONDITIONS

Planning and realization of field-scale plans in many respects take precedenceover experimental work. Hence it is necessary to investigate the methods suited thebest for measurement and evaluation of physical conditions promoting or essentiallyinfluencing erosion.

2.1. Slope angle

It has been found that appraisal of the effect of the slope angle is one of the mostdecisive objectives. On research work which led to the solution of this problem anaccount was made in the Symposium of I ASH held in Bari (Italy) October 1962 (3)therefore a short summary only should be reported here.

We divided slopes under agricultural cultivation into slope category ranges.These are the ranges of areas 0 to 5 per cent; 5.1 to 12 per cent; 12.1 to 17 per cent;17.1 to 25 per cent; steeper than 25 per cent; as expressed in per centage of slopeinclination.

On the strength of this classification we made in 1962 a survey of the total areaof the country endangered by erosion on the 1 : 100,000 scale, by drainage basins andadministration units. This survey involved ploughed area, grassland, vine and fruitplantations. Forests were surveyed independently of slope angle; meadows and marshyareas have been also separately assessed. The computation of slopes on the 1 : 25,000scale by slope category ranges with the elaboration of comprehensive soil conservationplans for drainage basins is on the way now. This computation and mapping provedto be a readily utilizable method in the course of elaboration and use of plans accom-plished so far, as an excellent means of the guidance of production in mountainousand hilly regions.

2.2. Slope length

For quantitative establishment of technical measures (mainly terracing) slopelengths also have been examined. With 1 : 25,000 scale maps containing 10 m contourlines it was found most suitable to the purpose in view to use the points of intersectionof the Gauss-Kriiger network for representative measurement. The length of thoseslopes is measured which are determined by the intersections of the network. Measure-ment extends on the map from watershed divide line to recipient.

In these measurements the characteristic slope angle of the slopes is also determi-ned, including forests, and agricultural areas.

The slope lengths are grouped and the groups compared with the slope categoryranges. Slope length classification used is the following : 0 to 200; 201 to 300; 301 to400 ; 401 to 500 ; 501 to 700 ; 701 to 1000 and over 1001 m length.

2.3. Geology

Geological conditions of slopy areas are often deeply involved in the determinationof the structure of soil conservation. There are soils in Hungary the tractive forcerequirement of which points to clay, water regime to loam and plasticity to sand.

35

These contradictory features can be only explained with geological notions. Such aree.g. soils developed on andésite tuff. A proper choice of soil conservation measurescan be only made if the entire geological background is known. Knowledge of geolo-gical conditions is facilitated by the valuable series of maps of the country establishedby the Institute of Geology operating since 1868. The 1 : 25,000 scale geological mapsupplies useful data on all sloping areas. These maps are particularly instrumental inappraising whether there is justification for technical operations and by what meansthese should be carried out.

2.4. Pedological conditions

Several scientists well known on the world wide plane (Szabö, J., TREITZ, P.,SIGMUND, E.) have dealt since 1861 with the determination of pedological conditionsby different methods. Mapping work of a modern conception conducted under thedirection of KREYBIG, L., between the two World Wars and terminated in 1950 ledto the elaboration of maps on the I : 25,000 scale which up to a certain degree werealso apt to meet requirements of mapping for soil conservation planning. These mapsand the pertaining soil analysis records with explanatory texts refer to all such featuresof the soil layers involved in the radication of plants as influence crop production.

Work conducted between 1958 and 1962 resulted in the 1 : 25,000 scale Practical' Agricultural Pedological Mapping Network giving considerable support to soil con-servation planning on a higher level. This work was directed by G. GÉCZY of the Re-search Institute for Agricultural Economy of the Hungarian Academy of Sciences.These maps present cultivability, chemical and- humification conditions of the soils,deficiencies in surface and subsoil inhibiting plant growth, genetical soil types andsubtypes, tasks of soil melioration awaiting solution and damages caused by erosion,deflation and neglected water regulation.

Genetical type and dynamics of the soil, when due allowance is made to otherfeatures represented, provide for a fair possibility of evaluation. In 1 : 25,000 scalemapping of drainage basins within the limits of required accuracy water regime in-filtration capacity and resistance to erosion of the individual soil spots can be measured.

The genetical soil map of the Research Institute of Soil Science and AgriculturalChemistry of the Hungarian Academy of Sciences in many cases also supplies properguidance to the construction of plans for drainage basins. Its utilization requires,however, not only thorough pedological knowledge but also local informationbecause even within genetical soil types occurring in Hungary, erosion is of verydifferent degree. This is due to the geological layers of very different character partsof which came to the surface and partly to the different humus conditions.

When constructing uniform comprehensive plans for drainage basins the 1 :75,000 and 1 : 200,000 scale erosion maps of Hungary by E. MATTYASOVSZKY, P. STE-IANOVITS and T. DUCK are utilized informatively. This map has been discussed atthe symposium of IASH held in Bari, October 1962 (4).

On account of soil conditions being very varying in many cases — in view ofproper establishment of soil conservation methods — special soil maps of 1 : 5,000and 1 : 10,000 scale must be constructed delimiting the different soil spots and deter-mining the different features of the soil with an accuracy of ~ 20 m. The scale to beused depends upon the plicateness of slope and variety of soil in the area.

I-ield maps for soil conservation were developed by M. KAMARÀS on the groundsof the general field soil map type constructed by the National Institute for AgriculturalQuality Testing. The basic map developed by him comprises the genetical types andthe local variants indicating defects of top and subsoil which cause low producti-vity (stone, cemented gravel, sand layers, highly compacted subsoil, etc.) and the depthof their occurrence. The basic map is completed by 3 cartograms.

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1. Cartogram of humus stage and of physical soil varieties (Fig. 1);

2. Cartogram of lime stage ;

3. Cartogram of infiltration and erodibility.

Cartogram No. 1 comprehends thickness of the arable layer, humus content ofthe top soil divided into per cent categories corresponding to the type (deficient inhumus, humous, rich in himus) ; location of buried humous layer possibly occurringin the subsoil, classified according to the physical condition of the soil.

CARTOGRAM OF HUMUS STAGE AND OFPHYSICAL SOIL VARIETIES

depth of the huomus loyer23O number of piä

* with organic moäer well provided

K • potassium • «

P " Phosphorus • " . ,9 with organic matter medium provided 11 "-'."' | from 30 to 60 cm

K • potassium • *P • Phosphorus » • | \fr0m0t0 30cm

° low in orçanic matter

K • • potassium [ i l l medium loam

P • ' Phosphorus „ _ _ _

1% stony surface soil KXNl ha"y loam

/*\ very stony, subsoil with .^ hardpan depth ,n cm 1 ^ «°odland

Fig. 1

37

y

Cartogram No. 2 refers to the degree of unsaturatedncss in acid soils and limecontent in the top soil. For unsaturatcd soils the map also indicates depth of thecalcareous layers found in the top soil. Data necessary to the realization of limingand soil amelioration can be also pointed out in this cartogram.

Cartogram No. 3 indicates infiltration conditions and resistance of soils toerosion independent of plant cover.

Devices for direct measurement of water household and infiltration conditionsof soils were developed by B. SZEKRÉNYI and M. KAMARÂS. Both are suited for thestudy of original structured samples. The former apparatus is an automatic waterfeeder with writing and recording device for the simultaneous examination of twosamples while the latter makes the simultaneous reading of the results from 8 samplespossible by a semi-automatical method.

When starting the planning for soil conservation no such method was availableyet to make it possible to determine the behaviour of soils under the action of erosionin laboratory tests. Therefore the value of the resistance has been determined withdue allowance to the genetical soil type, to mechanical composition, structural condi-tions, quality of clay minerals, quality and quantity of adsorbed cations, by assess-ment, corrected with the data of local observations. While searching for a properlaboratory method M. KAMARÂS in 1960-1961 developed an analytical technique basedon wet sieving. This method according to experience obtained up to now seems to be a

ERODIBIUTY CURVES OF SOME SOIL TWESfaccordinç tö Kamarâs J

Erodîbility

100 -

00

eo

10 -

eo -

so -

30 -

20

«7

no Z.

hour

Fig. 2

readily available approach to the determination of soil erodibility. The theoreticalfoundation of the method is the particle size which on an average (10 per cent) slope,at a given specific weight, resists to the sweeping force of a 2 mm thick water sheetmoving down the slope. In average soils this particle size corresponds to 0.9 mmperticle diameter. Per cent of soil quantity with resistant particle size makes it pos-sible to compare erodibility of different soils (Fig. 2).

Values thus obtained supply, by the use of a Table, the (T*) factor of the soilresistance determined by KAMARÂS.

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2.5. Intensity of soil denudation

Determination of the intensity of soil losses is a basic task of both perspectiveand field scale planning. Determination can be carried out mainly by geodetic survey,by extrapolation of exact measurement results of smaller gully areas to larger areasby aerial photographs. In the course of development of plans for soil conservationequipment of drainage basins as a result of investigations performed — by applicationof the above method — we have established the present intensity of soil loss with anestimated accuracy of 20 to 40 per cent. According to our findings the rate of soilloss is rather different in the various regions of the country, reaching 45 to 200 t/ha/yearin the highly endangered vineyards and arable land. For the total area the mean natio-nal value ranges from 40 to 50 t/ha/ycar.

In the study of soil losses and surface runoff the observation station of the Institutefor Forest Sciences has a prominent role. The station has been established in 1952in the northern mountainous district of Hungary on here and there highly erodedbrown forest loam on rhyolitc tuff parent rock. Its total area is 4.9 ha with a slopeangle of 3 to 40 per cent and about 570 mm average annual precipitation.

The station is equiped among others with a deep Thompson weir, and ombro-graph, different check dams and first class meteorological post.

During the 4 hydrological years from 1956 to 1960 the following per cents oftotal precipitation have flown off the various type areas of the drainage basin :

from typical woodland 1.1 per centfrom scattered top grass shrubby type interrupted sods in a state

of successive denudation 5.8 per centfrom top and bottom grass continuous sod pasture 8.0 per centfrom stony barren land without plant cover on volcanic tuff

parent rock 38.4 per centAverage intensity of soil loss during the 4 years of measurements in dependence

on canopy and slope inclination is shown in table 1.The most important result obtained is that 0.5 per cent of the sediment originated

from woodland, 3.7 per cent from continuous sod pastures, 7.4 per cent from top grassscattered shrubby area with interrupted sod, and 88.4 per cent from denudated barrenland. 91.5 per cent of sediment originated in the vegetation period as a result partlyof precipitations of higher intensity occurring in this period and of weathered soilparticles.

TABLE 1

Average intensity of soil denudation

I

Designation of type area

Afforestation zoneClosed sward pastureOpen sward top grass areaDenudated barren area

| Slope1 inclination! »/i /o

25-2911-2732-408-37

Annualdenudation

t/ha

0.190.821.00

194.00

For exact determination of the intensity of soil losses and of the surface runoff,in the praire soil belt of Western Hungary in an experimental farm a trial ground of43 ha with 5 to 8 per cent inclination has been established on slopes of 300 m average

39

length where the water retention and erosion inhibiting effect of sliip cropping, farm-ing on the contour, terracing, slope drainage system combined with terracing, areobserved with modern measuring and observing equipments (Fig. 3a and 3b).

A-A section

Thomson weir

— collector canal

Fig. 3b

The various types of agronomical and technical equipment of the area have beenconstructed in 1961-62. Thus measurements and observations can be carried outbeginning with the current year. For continuous performance of the experimentsand emancipation from natural precipitation in the valley below the experimentalfield two smaller ponds are built which will supply water to the rainfall simulatorassemblies to be built subsequently.

2.6. Meteorological and hydrohgical conditions

Planning for soil conservation must evaluate meteorological and hydrologicalconditions.

From the angle of erosional soil losses it is most important to determine zones,intensity and periods of high intensity showers.

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The first study that set as an objective to work up data on intensity of precipi-tation on the national scale was the internal specifications of the Design Bureau forCivil Engineering developed later by Z. BABOS and completed with an investigationof the properties and territorial distribution of the extraordinary precipitations(showers) that attained the area of the country.

Both works indicate for 12 districts of the country the a and n values of the pre-cipitation function

where e = intensity of precipitation obtained within the t time in 1/sec/ha for 1/3,1/2, 1, 2, 4, 10, 20, 50, 100 year's frequencies. The data have been also graphicallyelaborated.

Besides the precipitation intensity values occurring with different probability itis also important to know the maximal flood discharge values of different probabilityoccurring as drainage basins. Investigations were carried out in this connection byB. CSERMÀK who constructed an isometrical map determining the values of the so-called specific flood coefficient occurring with a probability of B35/ for the whole areaof the country. The 3% probability flood has been calculated by the formula

03 = 03% • \/F

where Q = discharge (rate of flow) in sq.m/sec. and F = the area of water drainagebasin in sq.km.

Use of the rate of conversion of flood values of different probability makes itpossible to determine also the values for floods of other degrees of probability.

2.7. Effect of way of utilizing the land and that of the cultivation branch distribution

The choice of soil conservation method largely depends on the distribution ofbranches of cultivation on a given sloping area. Therefore when deciding on the utili-zation of the area it must be considered first of all whether it is justified or not to main-tain the proportion and emplacement in the area of the branches of cultivation.

The emplacement of branches of cultivation on the slope is established by eva-luation of the air photographs or by supervision on the spot. The results are representedon the 1 : 25,000 (for the valuable vine growing areas 1 : 10,000) scale slope categorymap constructed by ourselves.

Subsequently to the evaluation of the distribution and emplacement on the slopeof the branches of cultivation it should be examined by what method the slopes are uti-lized in the given area, particularly whether the field plots run parallel with the directionof the slope or perpendicularly; whether cultivation is carried out parallel with theslope and what is the proportion of crops in the cropping system. Conditions ofequipment and cultivation of vineyards, grazing system in pastures must be established.We must know conditions prevailing in the forests : whether they are pastured andwhether proper attention is paid to their exploitation and to the maintenance of forestpathways. For all areas supervised it must be established what machines they areworked with and whether these machines are properly used. We must make it clearwhat the proportion of forage growing is and what animal stock is kept on this forage.Is animal husbandry economically efficient and profitable and how far can the slopesbe provided with farmyard manure ? Finally we must appraise, how the area fits intothe economy of the country i.e. what role the agriculture of the area plays in the sup-port of population and what changes are required.

The appraisal of all this means thorough research work for the planners, whobesides the collection of data on the spot and the elaboration of the material of the

41

institutes work out also the economic index numbers and aids for planning which inthe plotting of the individual plans arc suited for the formation of the general pictureand at the same time ensure the evalution of all drainage basins of the country witha unanimous view.

By disclosing the position of crop husbandry we may point out its structuralfailures. These structural failures led in most cases to improperly shaped animal hus-bandry and only too often to unsound utilization of grasslands.

In the accomplishment of this task valuable help is supplied by the ResearchInstitute for Agricultural Economy of the Hungarian Academy of Sciences whichbesides the Practical Soil Information and Utilization Map worked out the structureof crop production and animal husbandry of the whole country broken down to villa-ges. This work was accomplished in 1962. Its objective was to discover the evolvedforms of the agricultural production of the country and hereby make it possible todevelop the most favourable qualitative and quantitative proportions of the cropsbest suited to the individual regions of production. The work comprehends — brokendown to villages — soil map, soil utilization map (the latter including distribution bybranches of cultivation and groups of crops best fitted to each region), economic,meteorological, agronomical data (broken down to crops), information on stockfarming, labour force supply, etc. Moreover it offers suggestions for more rationalutilization of the area.

All what has been said so far pertains to an assessment of present position.

3. SOIL CONSERVATION PLANNING

After having evaluated the natural and economic conditions we must decide onsoil conservation equipment of drainage basins and farms. Under soil conservationwe understand up-to-date farming in mountainous and hilly country ensuring thatthe remaining loss of soil under the conditions of Hungary does not surpass the 15t/ha/year value. The method is based on the maximum possible agronomical soilprotection supplemented according to necessity with technical processes.

3.1. Readjustment of farms

To be able to realize the above principles of soil conservation in practice wemust appraise the situation of the farms in the drainage basin and on the individualslopes respectively. When the farms possibly extend over the ridges of steep slopesinto foreign catchment areas or if the areas of several farms come to lie below eachother on the slope.it must be established how to perform an exchange of areas amongthe farms in order to obtain most proper distribution of farms on the slopes from thepoint of view of soil conservation and cultivation. The farms by the new shaping oftheir area must gain a sound foundation for farming to establish the desirable propor-tions of the branches of cultivation and to ensure such conditions as agree with theinterests of the territory from the angles of national economy and farm management,making best utilization possible.

At the same time it must be examined in the course of planning what farming pro-file is justified to be established by the equipment of the area along the above lines(intensive forage production and appropriate stock farming, or fruit and vine cultureetc.).

3.2. Redistribution of cultivation branches

The next step is to determine how the branches of cultivation should be distri-buted on the slopes.

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Here we must point out what has been said above on slope categories, because inthe following, possibilities and targets should be evaluated on these grounds. Emplace-ment of branches of production, establishment of the cropping system, mechanization,distribution of labour force requirement and, in the long run, also profitability of thefarm essentially depend on the distribution of slope category ranges. All sloping areasmust be excluded from field cultivation the inclination of which exceeds 25 per cent.Pastures — depending also on other natural conditions — should be establishedmainly on northern slopes of 12 to 25 per cent inclination. No pastures are left onslopes steeper than 35 per cent inclination. Vineyards are planned to be establishedon southern slopes of 0 to 40 per cent inclination. Agricultural areas of over 25 percent slope angle will be utilized, depending on natural and economic conditions, forthe establishment of vineyards, orchards, swards or forests.

Emplacement and evaluation of branches of cultivation according to these prin-ciples in planning for drainage basins is carried out on the grounds of aerial photo-graphs, slope category mapping, comparison of soil maps and in farm planning alsoby detailed local supervision.

Utilization of arable land established on the strength of the emplacement of newbranches of cultivation should be decided upon again with due regard to pcdologicaland climatic conditions mainly by the slope angle.

Besides making use of experimental results gained in foreign countries — utilizingthe possibilities available — we endeavoured to rely also upon domestic experiments.

3.3. Soil conservation efficiency

Under the conditions of identical pedological cultivation and slope conditionswe established at what depth below the natural or artificially produced watershederosion appears under the various crops upon the influence of precipitation fallen inthe individual narrow districts the amounts of which may be taken for identical. Onthe strength of these observations we have established the sequence of crops by thesoil conservation efficiency of plants (table 2).

TABLE 2Groups of crops by soil protective effects

Rankingwithin

thegroup

1

2

345

6

78

High (W)

Permanent sod

Hay

LucerneRed cloverSainfoin

Bird's foottrefoil

Medium (M) Poor(R)

Soil protective effect crops

Crimson clover-rape

Winter forage

Summerforage mixture

Peasmixture !

Winter barley ! VetchesRye : Green maizeSummer barley, ; Sudan grassoats

Winter wheat

Potato

Soybeans

BeansPotato

Low (B)

Fodder-beet

Sugar-beet

TobaccoMaizeSunflower

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3.4. Creation of experimental plots and farms

We succeeded in creating the first possibilities of systematic experimental workin a farm unit of a state farm near Budapest. This farm unit, the total area of whichis 200 ha, has been installed according to the internationally acknowledged rules ofsoil conservation. So — besides the agronomical experiments — it became possiblefor the Institute for the Testing of Agricultural Machinery to investigate the mechani-zation problems of soil conserving cultivation under the direction of K. LAMMIX.The installation of this farm unit commenced in 1960 and was finished by 1962. Ex-periments set up in this farm unit are expected to supply the answers to many questionsof soil conservation farming. So among others the effects of contour cropping, stripcropping and terracing — diminishing the surface runoff and sediment production— and soil protective capacity of the individual crops and of the cropping system wereinvestigated. For all these the results of experiments conducted for a proper time arcstill missing.

One of the main objectives of experiments set up in the farm referred to andconnected with farm mechanization was to develop appropriate readjustment of fieldplots in sloping areas. It is desirable for readjustment of field plots not only toassure possibilities of soil protective cultivation and care of plants but also ofeconomical and technologically unexceptionable machine work. The work path or fieldplot length had to be established which corresponds to the minimum effects of econo-mical exploitation of the machines. The necessary time studies and calculations havebeen carried out in 1960-61. It has been established that in case of machines providedwith hydraulics and belonging to the 30 to 35 HP category about 200 m is the minimumfield plot length with which the motors can be still profitably exploited. In the case ofhauled implements this distance is 300 m. In the case of such work path length themachines perform useful work for about 85 to 90 per cent of total time spent. Fieldplot and strip lengths of these dimensions can be realized in most cases if the smallergullies hindering the cultivation are graded. The upper limit of field plut length causesless trouble because if a way can be established at both ends of the field plots thetransportation tasks can be still met economically at a field plot length of 1 000 to1.200 ms. The surface conditions in generally do not allow in Hungary to form greatfield plot or strip lengths reaching 1 000 m.

Width of the field plots if cultivable terraces can be built over them has no specialsignificance. On slopes above 12 per cent the width of field plots and strips has rathersignificance from the point of view of soil protection than from the angle of agricultureand production techniques. Therefore the width dimensions have been establishedwith due allowance for slope conditions, general soil conditions and protective effectsof the planned crops.

It is most suitable for the purpose in view to choose such average size of fieldplots that those belonging to the same type of crop rotation should be nearly equalbut in all cases at least so large that in the course of the main soil cultivation and harvest-ing works the machines may find enough to do for a whole day or its multiple by awhole number. Six ha is considered as the lowest field plot size still affording possi-bility for economical farming. Average field plot size is generally 20 to 30 ha.

Realization of readjustment of field plots for soil conservation was made possibleby large-scale reorganization of agriculture. As long as the narrow small striplikepatches in the slope direction were preponderant, ownership conditions excludedthe possibility of horizontal cultivation. Reorganization, however, did not mean atthe same time readjustment of field plots for soil conservation. The new field plotlimits formed along the former farm roads which in most cases constituted no possi-bility but rather an obstacle for realization of readjustment of field plots for soilconservation.

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Readjustment of field plots and shape and size of fields in sloping areas must bein close conformity with cropping systems pertaining to the individual slope catego-ries. The emplacement of field plot types on the slope is properly illustrated by theplan of the installation of the experimental farm unit referred to above (Fig. 4). Onslopes between 0 and 5 per cent there are no fixed forms for the readjustment of fieldplots. Between 5 and 12 per cent 80 to 160 m wide horizontally cultivated field plotselongated transversally to the slope are regarded to be most suitable for the purposein view. When in field plots situated above each other simultaneously crops of differentprotective effect are cultivated the so-called broad strip system results. On slopes be-tween 12 and 17 per cent inclination strip cropping has been realized the soil protectivemechanism of which is well known. Width is established on a range from 40 to 80 mwith due allowance to the pedological factor so that it should constitute a multipleby whole numbers of the dimensions of the machines applied.

FIELD PLAN OF THE FIRST SOIL CONSERVATIONPILOT FARM IN HUNGARY

7i crap rotation nth farmingA on the contour

Fig. 4

Field plots, broad strips and narrow strips particularly serve economic efficiencyof large-scale mechanization better if their longitudinal sides are parallel to eachother. This postulates of course perpetual grass or forest cover of some part plots.The surface lost this way, however, used to be insignificant even in plicated areas andas a rule is compensated by higher efficiency of machine work. We do not regard,however, the principle of parallelism as compulsory ; but rather as desirable. Deviationfrom the principle is tolerated mostly when the area on a higher percentage of theyears is covered by sod which requires no soil cultivation — as in the the case of croprotations with alternating pasture — and whenever there is a possibility for the frequentturning of machines which thus becomes necessary ,i.e. in the case of broad field plotsbordered by farm roads.

On 17 to 25 per cent slopes the simple strip cropping in most cases does notafford satisfactory and economically efficient protection. Therefore it is justified toincrease the plant cover. For the realization of this aim we developed the so-calledsoil conservation crop rotation type with alternating pasture where the grass-coveredcourses amount to 60 to 70 per cent. The field plot dimensions in the crop rotationwith alternating pasture arc not so fixed because only about 30 to 40 per cent of thecrop rotation courses must be cultivated each year and in the smaller area field plotdimensions can be tolerated which result in a less favourable exploitation of the machi-nes. This offers the advantage that the plots are better adjusted to soil surface conditions

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3.5. The general cropping system

When the area is thus arranged, crop husbandry can be started. Research workand methodical investigations both on realization indicate that crop productionitself must be grouped by slope categories and adjusted to the rules of soil conservationthe more as mechanization of cultural techniques and cultivation are also closelyconnected with slope category ranges. The task of the establishment of the croppingsystem is different, however, when the areas of large drainage basins are examinedand when planning for farming is carried out. While a single farm is free to grow indi-vidual, selected crops only and to cover the starch and protein missing from the feedof animals by purchases, larger regional units must grow the individual crops at aproportion corresponding to the requirements of the country.

When planning for the proportions in crop husbandry of the larger drainagebasins first of all the whole produce requirement of the country had to be assessedand subsequently broken down by plain and sIODing areas, then to sown areas orme individual drainage basins with sloping areas. In the course of this operation theslope category distribution of different composition must be reflected too.

The starting basis for the national survey was the several years' average of thenational cropping system corrected by the data of the 20 year development plans. Theproportions of the plant groups forming in the case of development to be expectedin the next years to come were worked up and the problem studied how these couldbe arranged, divided on all slope category ranges of the country according to viewpointsof soil conservation. The target was to develop types of crop rotation for the individualslope categories so that the groups of plants which are involved in different proportionsin each slope category should result as a total in the desired national proportions.The crop rotation types had to be rendered suitable to be utilized in soils of variouschemical reactions and physical features. This objective was largely attained by esta-blishing the type of crop rotation relying not on single plants but on the groups ofplants with different soil conseruation effects.

Within the groups crops can be chosen which are most adapted to region andsoil. Only the strip cropping system forms an exception where in calcareous soilsmainly lucerne (Table 3) while in acid soils red clover and one of the winter cereals(Table 4) forms the shelter belt. Therefore the different physiological properties oflucerne and red clover result here in two crop rotations with different protective effects.In the application of red clover a 4 year rest was reckoned with to avoid soil fatigue.

Key to the signs used in the examples for crop rotation to be used on 12 to 17 percent slopes (Tables 3 and 4).

W = highly protective plant group

M = medium protective plant group

R = poorly protective plant group

B = low protection plant group

Crop rotations with alternating pastures for 17 to 25 per cent slopes make it possibleto plant higher yielding periodical pasture in the slope category where rational grazingdoes not cause damages yet. Favourable conditions for manuring in the croppingperiod, loosening and aeration of soils compacted by trotting opens possibilities forhigher yields than do permanent pastures. At the same time they participate in pro-duction — up to a certain point — as arable land. In the cropping courses in confor-mity with the character of crop rotations with forage crops, alternately winter wheatand maize for silage are produced in strips.

The borders of every second strip of the area are occupied by a fence to limitthe grazing courses. Thus in the grass course only the broader strips are separatedfrom each other.

46

TABLE 3

Crop rotation with lucerne on calcareous soil

1. strip2. strip3. strip4. strip5. strip6. strip7. strip8. strip

1.year

WRWRWRWR

Greenmaize

2.year

WMWMWMWM

Winterwheat

year

WBWBWBWB

Potato

4.year

WMWMWMWM

Winterwheat

5.year

RWRWRWRW

Luc.

6.year

MWMWMWMW

Luc.

7.year

BWBWBWBW

Luc.

8.year

MWMWMWMW

Luc.

TABLE 4

Grass-red clover crop rotation on acid soil

1. strip2. strip3. strip4. strip5. strip6. stripA*AZKG

1.year

WMRMRW

2.year

WWMRMR

3.year

RWWMRM

4.year

MRWWMR

5.year

RMRW

wM

6.year

MRMRWW

7.year

WMRMRW

8.year

WWMRMR

9.year

RWWMRM

10.year

MRWWMR

11.year

RMRWWM

12.year

MRMRWW

The crops of the 1. strip can be in the course of years :1. year red clover with grass, 2. year red clover with grass, 3. year maize for

silage, 4. year winter wheat, 5. year pea, 6. year winter wheat, etc.

According to the same principle, after a 6 year grass course in 3 year's croppingplant proportions of 70 per cent high, 15 per cent medium and 15 per cent poor soilprotective effects can be realized too. In this crop rotation it is sufficient to realize 3courses at a time, to assure continuity of the crop rotation. In this case breaking upof the sod or seeding of grasses respectively occurs in every third year only. A croprotation of this type has been realized in the 200 ha soil conservation experimentalarea near Budapest.

While the proportions of protective effect groups established for the slope cate-gories between 12 and 25 per cent involve a strict compulsion bound to certain crops,

47

on the 5 to 12 per cent slopes the plants can be chosen on a wide range depending onsoil conditions, without changing the proportions between all groups of plants withprotective effect.

TABLE 5

Crop rotation type with alternating pasture, suited for 17 to 25 per cent slopes with 60per cent high, 20 per cent medium and 20 per cent poor protective effect crops.

1. strip2. strip3. strip4. strip5. strip6. strip7. strip8. strip9. strip

10. strip11. strip12. strip

1.year

W

wwwwwwwMRMR

2year

W

wwwwwwwRMRM

3.year

WWW

wRMRMW

www

4.year

WWWWMRMRWW

ww

5.year

MRMRWWWWWWWW

6.year

RMRMWWW

wwwww

7.year

W

wwwwwwwRMRM

8.year

WW

wwwwwwMRMR

9.year

WWW

wMRMRWW

ww

10year

WWWWWMRMWWWW

11.year

RMRMWW

wwwwww

12.year

MRMRWWWWW

www

In the case of crop rotation with alternating pastureW - hay (ley)M = winter wheatR = maize for silage

On the 0 to 5 per cent slopes the proportions between acreages are restricted onlyby considerations related to preceding crops and economy of soil fertility. In theseareas, however, must be produced also the row crops deficient in the 12 to 25 per centareas as related to national ratios. On the other hand, the acreage of the high protec-tion crops must be diminished here by the amount appearing as a surplus on the12 to 25 per cent slopes in comparison to the national proportion. Hence for the areasbelonging to the 0 to 5 per cent slope category two crop rotation frameworks havebeen developed with different proportions. One of these, crop rotation "A", shouldbe introduced on an area of the same size as the total surface of the 15 to 25 per centslopes. This crop rotation will balance the cropping system proportions of the steeperslopes shifted as compared with the national ratio. The other ("B") crop rotationcorresponds by and large to the national proportions. Composition and applicationaccording to slope categories of crop rotation types are presented in Table 6.

The cropping system referred to has been developed by M. KAMARÂS. On this.basis the present authors calculated the crop ratios desirable for the drainage basinsof all water courses in mountainous and hilly regions of the country. The relativedata for the mountainous and hilly country most and least endangered by erosionand for the total sloping area are presented in Table 7.

The main advantage of this system consists in making possible to build in theplant production ratios of the smaller or larger drainage basins into the nationalframework ; at the same time it shows an elastic adaptability to soil conditions and tospecial aspects of individual farms, facilitating the planning for agricultural installa-

48

tions based on slope categories. Its disadvantage is that the protective effect changingwith the progress of soil conservation technique becomes bound to the crops whichmakes a periodical revision and adjustment of the system necessary.

TABLE 6

Proportions by protective effect groups in frame work crop rotations applied in differentslope category ranges

Crop rotation type

A (compensating crop rotation)B (average crop rotation)C (broad strip crop rotation)D (Strip crop rotation in cal-

careous soil)E (Strip crop rotation in acid

soil)F (Crop rotation with alterna-

ting pasture)

w/ o

101720

50

33.3

60

M

403340

25

33.3

20

R

%

101720

12.5

33.3

20

B/ o

403320

12.5

Slopecategoryrange, %

0- 50- 55-12

12-17

12-17

17-25

In the course of the installation of farms great attention is paid to the planningfor the transitory years. According to experience gained plans can be only carried outsmoothly and without undue delay when a precise schedule is available in whichstarting from the original field plot and cropping system the progress of the transfor-mation of each part plot is elaborated in full details, indicating also the date of reali-zation. The period necessary for complete reorganization is generally three years

TABLE 7

Ratio of soil conservation crops in mountainous and hilly country(Comparison in nation-wide dimensions)

W

Country most endangered byerosion

Country least endangered byerosion

On total sloping area

31.9

17.821.4

30.5

35.034.8

15.1

17.517.8

22.5

29.326.0

but is largely influenced by the emplacement and age of perennial crops. The transitoryperiod is planned for as a rule so that production should be continuous and free ofinterruptions as far as possible. In the plan agronomical and technical targets appearinterwoven. None of the plans for individual farms has been established so far underconditions that might have justified neglect of this rule and therefore the tasks could notbe restricted for a single farm to one single year.

49

In 1960 a similar equipment of the 1.000 hectare area of a co-operative farm inthe North Eastern mountainous district of Hungary was initiated. This farm willalso afford a good opportunity for systematical evaluation of soil conservation prac-tices by the results of experiments and observations conducted on this area.

In 1961-62 in the loess region of Western Hungary installation works were ini-tiated in two state farms and a co-operative farm to establish large-scale experimentalfields suited to serve measurement and evaluation of the efficiency of soil conservationpractices. The same farms fulfil also model and demonstration purposes. Experiencegained so far, however, is not sufficient as yet to form the object of an account.

In Hungary destruction caused by erosion is in many cases most important inpastures, as a result of improper grazing.

When planning for soil conservation and equipment of great drainage basins inall cases the trends in animal husbandry and in this connection ley farming andmanure balance are investigated pointing to failures and to possibilities of improve-ments.

Manure balance and replacement of organic matter are in mountainous districtsof great importance for soil conservation. These considerations are leading to theproblems of soil reclamation in sloping areas. The effects of the various methods ofsoil reclamation on water regime and erodibility in sloping areas deserve specialattention. Under such conditions methods are generally successful when they act as acomplex process on physical, chemical and biological properties of the soil.

3.6. Soil reclamation

In sloping areas of Hungary as a rule two kinds of soil are found which needreclamation viz. the group of forest soils leached out by different processes and highlycalcareous crude loess soils completely devoid of their humous layer as a result ofintensive denudation.

Melioration of acid soils with liming is generally performed in Hungary for manydecades. It is a long standing experience verified by experimental results and scientificinvestigations that for liming the soil improving substance must be spread out repeatedlyin small doses, always associated with large doses of organic manure and growingof crops with great amounts of roots. This is the only way to assure the gradual for-mation of larger soil crumbles more resistant to erosion.

The biological soil melioration method worked out by B. MEZÖSY with theutilization of muck, to improve soil structure, used in the mountainous and hillyregion of Hungary for nearly two decades and increasingly acknowledged, deservesspecial attention. It has a high importance for sloping areas.

According to this practice on the soil loosened by previous disc tilling 350 q/hamoderately acid muck soil mixed with chemical fertilizers is spread out and added ina depth of 10 cm with disc harrows to the top soil. The top soil thus enriched withorganic matter is ploughed with a deeply turning plough without skim colter in adepth of 60 to 65 cm turning always upwards so that the plough rather tilts than turnsthe furrow slice. Herewith 30 to 35 cm wide downwards tapering strips rich in organicmatter are obtained which are shutter like tilted against the slope. Between these stripsoriginal soil is emplaced in the same width. The obliquely tilted strips overlap the un-treated strips. Subsequently 170 q/ha muck soil enriched with chemical fertilizers and85 q/ha decomposed farmyard manure is spread on the top soil and flatly ploughed in.

The transversal stratification of the soil profile of cumbling structure obtainedby deep cultivation prevents the loosened soil from compacting again. The humousstrips as a sort of biological counterfort lend elasticity to the soil and on the otherhand the heat and water household of the transversal strip soil profile follow different

50

trends in the humus and loess strips. Upon the action of the arising differences inheat and water regime a repeated loosening of the soil profile sets on.

In the course of experiments initiated in 1961 in the western hilly region of thecountry analyses conducted on the spot and in the laboratory in autumn 1961 demon-strated per cent changes of water content as condensed in Table 8.

TABLE 8

\Vater content per cent in

Depth Non meliorated strips I Meliorated strips

0 to 6 cm38 to 44 cm55 to 62 cm

100 to 106 cm

5.28.49.8

13.2

7.212.323.319.9

At the date of investigation in the non meliorated strips the maize plants discon-tinued their vital activities while in the meliorated strips they freshly thrived. In 1961when precipitation during the growing period was 103 mm in the hilly country ofWestern Hungary on loess soil the maize variety Red King yielded 29.5 q/ha on thenon-improved territory whereas 45.2 on the ameliorated strips. In the trial fieldsreferred to above an excellent Hungarian maize hybrid yielded 31.3 q/ha raw cornin the ear and 77.2 on the average in the ameliorated strips.

Efficiency of the method is enhanced by planting first lucerne in the soil preparedwith deep ploughing in of muck because this way undisturbed conditions can be pro-vided for in the soil and there is time enough for the treated and untreated strip toreach a uniform maturity by the biological activities proceeding in the soil.

3.7. Soil conseruation practices of forestry and their effectiveness

Since deflation must be reckoned with on important areas of Hungary, forestryis engaged for a long time in studying the soil protective effects of shelter belts.

Composition of shelter belts is developed to obtain uniform permeability towinds in their whole cross section, in order to avoid the formation of frost and heatholes. Since sandy areas of Hungary must be protected mainly against blow off bythe wind, thinner shelter belts are also suitable to the purpose in view. Their widthshould range from 6 to 12 m always according to the given conditions of the area.

According to investigations of the microclimate in zones protected by shelterbelts the velocity of the wind was reduced by 20 to 30 per cent ; at the same time thevalues of relative humidity rose by 15 to 20 percent. Temperature of the air was notmuch influenced by shelter belts even in the immediate environments although it hasbeen established that in protected areas the air was warmer by about 1°C, the tempera-ture of the soil on the surface by 4 to 5°C and in a depth of 20°C by 1 to 2°C. Thesoil in a depth of 20° C contained 3 to 4 per cenl by weight more moisture while snowaccumulation was as high as 30 per cent in some cases.

In an experimental sylvicultural unit established in Northern Hungary the In-stitute for Forest Sciences performed model gully control in fractured quartzite, finelyweathering sandstone, lime and rhyolite tuff rocks.

In recent years increased attention was paid to forest soils from the angles of waterhousehold and soil conservation. Ü. BIRK by his experiments conducted in 1957 to 1958elucidated the water regime conditions in the litter of forest tree species of Hungary.

51

3.8. Farm mechanisation

Studies of mechanized cultivation of sloping areas had to solve two tasks at thesame time. First of all the basic soil cultivation works and means had to be establishedwhich were to supply the tilling system best suited for sloping areas and subsequentlythe motors and machines had to be selected which are best suited for the cultivationof slopes. Most of this work had been performed by the Institute for the Testing ofAgricultural Machinery. ,

Experiments were conducted to study both the tilling systems known to be mostefficient and those that are most generally employed. Experiments extended to plough-ing both in the direction of the slope and horizontal (turned towards mountain andvalley), to the application on slopes of various rollers, tie ridger damming units andsubsoil ploughs as well as to the establishment of the energetical characteristics ofdifferent ploughing methods. Effects of soil cultivation operations have been deter-mined by measuring the depth of infiltration and amount of the lost water and trans-ported soil. Briefly summarized, investigations led to the following results :

The harrowing of the ploughed soil in case of ploughing along the slope somewhatincreases, in case of ploughing along contour somewhat reduces the amount of waterinfiltrating into the soil. Ring roller used in tie ridger damming work affords signi-ficant protection even in cultivation along the slope. Most efficient in soil conservationproved to be subsoil loosening coupled with ploughing along the contour. Follows —in the case of stubbles — cultivation with winged hoes, on the contour under the soilsurface and simple deep loosening.

Tractors and machines progressing on the slope along the contour work underdifferent conditions than in the case of cultivation along the slope. Therefore theInstitute deemed it necessary to numerically establish the effect of the direction ofcultivation on the work of tractors and engines. According to measurements in thecase of ploughing along the contour, turning towards the mountain which im moreadvantageous from the angle of soil conservation over a 10 per cent slope involvesconsumption of less fuel than turning downwards whereas in the case of cultivationalong the slope fuel consumption of the tractor was invariably higher than inhorizontal cultivation.

In the construction of the best suited type of power engine investigations weredirected to evaluation of the safety, efficiency of tractive power and dirigibility (lateralslip) of the horizontally progressing tractor. According to experimental results fourwheel drive tractors proved to be most suitable to cultivation along the contoursince beyond the high efficiency of tractive power the high degree of dirigibility makesthem well adapted to the cultivation of sloping areas. Manufacturing is,conductedat present in the 30 and 60 HP category types.

When searching for the most adequate plough type the semi digger beast-boardploughs proved to be best suited. Turning of the furrow slice safe from falling backwas attained by increasing the width to depth ratio (k) of the furrow. Best work wasperformed when k — 2.

As a result of these studies the two way plough types were developed for the 30and 60 HP category tractors provided with hydraulics.

Suspended construction of machines in sloping areas is absolutely justified in allimplements except for the roller.

In the course of these studies the machines were developed which arc indispensablefor the cultivation of sloping areas in Hungary.

For the works requiring low amounts of tractive power, first of all for the care ofplants, the implement carrying tractor type is used. Implements placed behind thefirst wheels make it possible to exactly follow the rows. Seeding, planting, fertilizerapplication in field plots of strip cropping, spraying and dusting with herbicides,harrowing etc. are carried out with these machines.

52.

Power engine and machine types required for the different slope categories havebeen developed with due attention to the most suitable cultivation methods evolved.In comprehensive soil conservation planning for the larger drainage basins, basedupon the ratios in the cropping systems elaborated the amount of power enginesand machines necessary for soil conserving cultivation of sloping areas has beenassessed on the national scale.

3.9. Technical establishments to interrupt surface runoff flow (terraces and belt ditches)

So far we have mainly dealt with the evaluation of methods in agronomy, partlyin forestry. Now let us revert to the statement that soil conservation is based on agro-nomical methods completed according to necessity by technical establishments.

As pointed out previously (3) our calculations are partly based upon researchperformed by the American workers BLAKKLY, COYLF. and STKF.LF. ('). In order toaccomplish harmony between agronomical and technical installations, we searchedfor the slope lenght L at which — all other factors being known — a 15 t/ha/yeartolerated loss of soil arises. The results of this calculation are condensed in Table 9.

The distances indicated in the Table are those at the limit of which the surfacerunoff— in the interest of soil conservation — must be interrupted with some technicalestablishment (terrace, belt ditch, bench terrace).

Terracing works conducted in 1950-51 resulted in a failure. When analysingthe lessons a new type of terrace had been developed which interrupts the surfacerunoff, — in combination with the maximum agronomical protection possible. Theyhave a great length of base, while being placed at a comparatively great distance fromeach other on the slopes.

Unfavourable infiltration conditions of the brown forest soils dominating in thehilly country of Hungary in most cases preclude the employment of water infiltrationterraces with horizontal or dammed up water level. Base lengths of terraces havebeen increased to 12 to 16 m. Maximum fall of the bottoms of terraces is 3 to 5 permille, water conducting cross section 0.6 to 1.0 m2 Maximum angle of banks of terraceridges is 20 to 22 per cent and the radius of the circular are including the slopes ofterrace is greater than 8.0 m.

The upper slope inclination of terraces cultivable with machines has been fixedat 12 percent. In the case of steeper slope angles so called bench terraces or belt ditchesare used which naturally can be not only sloping but depending on the infiltrationconditions also horizontal or of a dammed level.

The incut part of the bench terraces (Fig. 5) is suggestive of a bench while theslope is reminiscent of a terrace. The bench terraces must be always placed on thecontour lines of strips, in contrast to the cultivable terraces which should be ratherplanned in the centre line of strips.

We gained ample experience both on cultivable and bench terraces in differentregions of the country. It seems advisable, however, to counterbalance the losses inyield caused, by terracing by biological improvement of the incut sides of the terraces.Related experiments have been conducted in a co-operative farm in Northern Hun-gary, with deep ploughing-in of humous muck soil ; the results were satisfactory.

Belt ditches were established exclusively with dammed water level construction.These should be applied mainly in plicated area where the inclination of the contourline of strips exceeds 0.5 to 1.0 per cent. In such cases the ditch stretches with a slopeangle over 1.0 per cent are provided with concrete slab cover while the ditch stretcheswith lower inclination than 1.0 per cent were built out to dammed water level. Thelatter solution supplied more favourable results.

The installations interrupting the surface runoff are connected with grass orconcrete covered waterways. The former are less expensive to build but it is not wholly

53

TABLE 9Medium distances of surface flow interrupting lines (terraces, bench terraces, beltditches etc.) at given pedological, precipitation and cropping circumstances permitting

15 tjha annual soil loss

Pedologicalfactor

•

Classifi-cationaccord-

ing Erodi-to

soilphysi- bility

calcondi-tions

Classifi-cation

accordingto

rainfallintensitypossibil-

itiesand to the

amountof totalrainfallduring

croppingseason

(*)

Soil categories

0-5% 5,1-12%| 12,1-17% 12,1-17%

Independently ; Onof soil chemical limy

reaction soil

Onacidsoil

17,1-25%

On limyand ac.soil

Cropping system according to slope categories and tothe conservation effectiveness of different plants (**)

%

W --•• 1 7 W - 20j W - 50M - 33 M - 40 • M •-- 25

i R = 17 R = 20 R =-. 12,5 | R = 33,3B - 3 3 B = 2 0 B = 13,5 B -= —

I W -= 33,3 . W = 60M - 33,3 M - 20

Distances between the interrupting linesat the slope in meters . . .

sand easily

sand diffic.sand easily

115 50 34 138

severemedium

sandsand

diffic.easily

mediumsmall

sandloam

loamloam diffic.

diffic.easily

smallsevere

easily mediumsevere

148 109

139

235

142

63 42 160

82 54

177 101

205

68 256

262 196 112 76 286

loam I diffic. mediumclay I easily severe

loam

331 357 141 95 359

easily I small j 376 ! 302 162 109

loam f diffic. : small |clay easily medium 418

408

clay316 161

diffic. severe

clay : easily smallclay diffic. medium

553 413 239

139

159

460

clay diffic. small 730 522 314 209

599

795

Possibility :(•) severe — once a year at least 28 mm/hour precicipitation in a period of 4

yearsmedium = equal to "sever" except "24-28 mm",small = equal to "sever" except "under 24 mm".

' (**) W ^ well, M — medium, R = restrictedly, B =•- badly

54

Terrace

Fig. 5

elucidated as yet whether they can be applied in areas of about 600 mm or less preci-pitation with reasonable safety. Concrete covered waterways are rather expensive andto a certain extent hinder the traffic.

The problem of establishments interrupting surface runoff are further investigatedto find out the optimum ratio between drainage and infiltration.

3.10. Optimum quantity determination of surface runoff flow interrupting technicalestablishments

Since in the hilly regions where agricultural utilization is general, from all soilconservation methods terracing requires the highest expenditure, it is justified toinvestigate this method from the angle of economic efficiency.

I. ALFÖLDY developed en evaluation method based on relationship betweenthe distance of terracing and agronomical protection, to mathematically determinethe economically most efficient amount of establishment interrupting surface runoff.The amount of terraces has been calculated on the grounds of Norton's "free oferosion" stretch.

36

wherexc — the erosion-free stretch (distance on the slope of the terraces from each

other)qs — intensity of surface runoff« — surface roughness according to Strickler-ManningRi — combined resistance to erosion of the soil and ils vegetation

sin a/(,) -= —- = — the factor expressing slope angle

tg^3

m = degree of turbulence, in case of turbulent water movement = 5/3.The hyperbolic relationship between the Ri value and the amount of terracing

affords a possibility for the study of the problem whether crop ratios for the differentslope category ranges have been planned at the given distribution of slope categoriesmost properly in view of the economical realisation of terracing. The essence of thisinvestigation is that the required length of terracing (ZJ) is a function of the quotientof the area to be protected (Ft) and the length of the stretch free of erosion (,vi).Thusthe number of terrace running metres required is obtained from a function of twovariables the one of the variables (xi) itself being the function of the average soilresistance (Ri). The graphical solution of the method is presented in Fig. 6.

55

EROSIOHFREE SLOPE LENGTHS IN CASE OF ONE HOUR DURATIONSTORM OCCURING ATLEAST ONCE IN THREE YEARS, CONCIOERING

AN ^.'0,5 RUNOFF FACTOR

017

amam

QBO

ax

ac

y

H

A

-\•Iv

Y/

Ay"

ft

y

4

y•i

yy^

/

m • sei,

te • Irm

y yy

y

hngto

y

mj

y

}'«fl

y

XI

I1

1 1

1

O 6X 3D W 30 S! 70 SBUJOj

Fig. 6

wo 3oo tm saoMcH

In determination of the amounts of terraces Fi/xt — n at the borders towards thevalley it must be taken into consideration that the slope length "free of erosion"xi is generally not a whole number multiple of the actual L slope length. Therefore wemust determine in each case a larger amount of terraces than necessary. The differenceagainst the actual position can be allowed for by a p, correction factor.

When plotting the zt values in the Ä, co-ordinate system hyperbolae arc obtained(Fig. 7). These hyperbolae for every possible mean soil resistance value (/?;) of theslope category supply besides the given /?; value also the number of terrace runningmetres assuring soil protection of the slope category. When the area of the slopecategory is given in per cents of total arable land a ratio is obtained which is in directproportion to the number of terrace running metres desired, consequently also withthe investment expenditure of terrace building and can be thus regarded also as an indexof investment.

The minimum of terrace running metres or of investment index related to thewhole drainage basin is obtained by determining the average soil resistance factor Rtof the individual slope categories so that by the function relations presented in figure 7the sum of the pertaining investment indices should equal the minimum. This pro-blem can be solved empirically. Fig. 8 serves the purpose to prevent us from trans-gressing the interpretation range of the task with the average soil resistance factors

. assumed for the soil resistance categories in the course of empirical trying so that thevalue of the slope category range soil resistance factor selected freely within certainlimits should be equal with the average soil resistance value given for the whole drai-nage basin. The evaluations carried out so far indicate that in planning for drainagebasins of a total extent of 90,000 ha optimum was approached with a difference of4 per cent.

The significance of the method actually is that it affords the possibility to plannersto control optimum distribution in the slope categories of the cropping system deter-mined by other than technical aspects, in order to assure minimum costs of constructiveworks interrupting the surface runoff which constitute the bulk of technical expenditure.

56

aiwo

os

OS

Off

m

ai

a*

03

0,2

aw oie a m œ at m an 07 OB as aFig. 7

Stopp cateçorijronge

ÛQ W ;2? 03 0-

Fig. 8

57

3.11. Establishments moderating the slope angle

We must also deal with constructive establishments reducing the fall, viz. benchterraces and other installations diminishing the bottom inclination of gullies.

In Hungary bench terraces are built exclusively for soil conservation in vineyardsand fruit plantations. Bench terraces for vineyards are established above 12 percent,for orchards above 17 per cent slope angle.

The terrace type best suited for up-to-date large-scale mechanization of vineyardareas has been developed by the soil conservation department of the Institute forHydraulic Planning by introducing 12 per cent ridge inclination and 0.5 per centlongitudinal fall. In analytical work concerning economic efficiency of bench terracesin vineyards the department succeeded in demonstrating a definite relationship on the-terrace areas between manual work for the care of vine exceeding mechanized workand economical terrace dimensions to be applied in the case of different slope angles(Fig. 9). As a result of these investigations it may be stated that minimum expenditureis obtained with terraces of average height and varying ridge width.

Ft/ha/year costsm HungarianCwrency

. Surrt of annual investment share and•' surplus cost due to annual labour; __ — #?%

WOO

500

surplus cost dueto manual labour

23.W 7,00 aw

9

aw n,un

m/mber of fine -stock rotrs

Fig. 9

In the practice of planning for soil conservation up to now profitability calculationswere conducted only in the medium level planning (for the regulation of drainagebasins of large extent). When planning for soil conservation on the farm scale, suchcalculations are conducted only occasionally, in case of soil conservation installationsrequiring greater investments in vineyards and orchards.

In plans accomplished so far, in the case of field soil conservation, amortizationwas calculated for 4 to 7 years while in viticulture for 10 to 12 years.

In profitableness investigations also the avoided damage per 1 Ft investmentis demonstrated, the value of which in the model plans accomplished hitherto wasabout 4 to 8 Ft.

3.12. Organisator}1 tasks

Finally, when evaluating the methods used in soil conservation, the question ariseswhether it is justified or not to subject the organisatory problems of execution to a

58

more thorough investigation. According to experience gained in Hungary, this hasa rather high importance. We have tried to carry out organizatory work by selectingsome farms and establishing execution plans for them. We tried on the other handto organize first of all a water regulation and soil conservation co-operative asso-ciation and endeavoured to realize plans by association. In both cases we made theexperience that an indispensable condition of success is special knowledge and far-ming discipline of the farm managers. If this condition is assured, realization by asso-ciations is surely easier, more proper and leads more rapidly to results ; it may be evenstated that this method is less expensive. For this purpose, however, the workingplans of all administrative and all educational organs must be co-ordinated andknowledge about soil conservation, up-to-date farming in mountainous and hillycountry incessantly popularized in the widest spheres.

REFERENCES

(1)B.D. BLAKELY, J.J. COYLE and J.G. STEELK, Erosion on Cultivated Land, TheThe Yearbook of Agriculture, Soil. Washington, 1957.

(2)R.E. HORTON, Erosional development of streams and their drainage basins,Bulletin of Geological Society of America, New York. Vol. 56, 1945.

(3) V. HORVATH and B. ERÖDI, Determination of natural slope category limits byfunction identity of erosional intensity, l.A.S.H. Commission of Land Erosion,Symposium of Bari, Publication No. 59, pp. 131-143, Gcntbrugge, 1962.

(4) P. STEFANOVITS, Fundamentals of erosion mapping of the Hungarian soil, l.A.S.H.Commission of Land Erosion, Symposium of Bari, Publication No. 59, pp. 15-18,Gentbrugge, 1962.

59