ÖZETBu çalışmada, Yukarı Pasinler Ovası Toprak ve Su Kooperatifsahasında bugünkü sulama durumu, mevcut toprak ve su kaynaklarınınrasyonel bir biçimde kullanılması ve muhafazasına ilişkin arazidevelopman hizmetlerinin geliştirilmesi ve sulama yönünden karşılaşılanproblemlerin ortaya çıkarılması ile bunların çözüm.! yollarıincelenmiştir.Araştırma bölgesi' hakkındaki genel bilgilerin, araştırmadanelde edilen sonuçların ve ilgili literatürün ışığı aİtında bölgede, sulamayönünden toprak-su ilişkileri, toprakların fiziksel ve kimyasalözellikleriyle bunların su tutma kapasiteleri ve uygulanan bitki paternidikkate alınarak sahanın sulama suyu ihtiyacı tesbit edilmiş, mevcut durumungeliştirilmesiyle ilgili hususlar açıklanarak tavsiyelerdebulunulmuştur.A RESEARCH ON IRRIGATION PROBLEMS AND THEIR SOLUTIONS AT THE SOIL-WATER COOPERATIVE AREA OF UPPER PASİNLER VALLEYPasinler Soil-Water Cooperativearea which is the research subject isin Upper Pasinler Valley of EastemTurkey. Cooperative area is consistof class I, II, III, IV, V and VI. landsand about 126830 dekars of cooperativeland is irıigable.Subject area so.ils are made ofalluvial and collivial soils. Theyarein zonal and azonal soil orders accordingto the soil genesis.Average annual precipitation ofUpper Pasinler Vaııey is 430,1 mm andmean yearly temperattlre is 5,9"C.Evaporation is maximum during Augustwhich has the highest mean monthlytemperature (34°C) of the year. Dryseason is between June 25 and September10; then inigation is necessaryduring this period.Irrigation water is supplied byground and surface water resources.The construction of ground waterusing irrigation system which is plannedto irrigate approximately 88 999 dekarsland is started in 1967, 56 million TLis invested for this job.This research is eonduetep, for thepurpose of surveying present irrigation. condition in the area Upper PasinlerValley Soi!-Water Cooperative, improvingthe land developmend servieeswhich involve rational use of the soilwaterresources, and fincling out theeneountered . irrigation problems.Result of field studies laboratorywork on soil samples and necessaryadvices can be stated as below:i. Irrigation water of this researcharea is not sufficient for needs; thereforeirrigation water should be usedvery economieally. Farrners are notfamiliar with modern irrigation practice.;hence water applieation efficienciesare very low. Theyare found between29 % and 46 % by experiments.. Waterapplication efficieneies 'are very lowbeeause farmers of this area do natuse the most suitable methods whiehfit the topographie and soil conditoions,applying more water then need, andusing a wrong time-table.2. Reseoreh subject area soils canbe classified as medium eoarse, mediumfine and fine according to their textuee.·Therefore texture of this soils are notlimiting factor for soil-water-plant relationshipş.3. Speeifie gravıtıes of soils ofprofile layers differs from 2,11 to 3;11as result of their textu·re. Bulk densitiesare between 0,93grfcm 3 and 1,86grfcm 3.4. Porosity values w1).ieh are calculatedfrom the relationships betweenspecific gravity and bulk density arebetween 29,54 % and 65,68 %' Porosityvalue are usually higher for upper layersthan for lower layers as a ıeusult oftexture, organic matter and compactionof soils.5. Pores are classified as eoarse,medium and fine. Distribution of poresis such coarse pores 0,81 %- 33,33 %medium pores 3,08 %- 33;04 % andfine pores 7,43 %- 36,71 % of totalpore space.The amount of wateı wh.ich willbe applied should be determined, verycarefully for every soil because of bigdifferences of pore size distributionof soils and low air cap~cities.6. Organic' matters of soil in theres?arch area is between 0,03 % and3,25 /~. Amound of organic matter isusualIy Law for tnese soils as result ofpraeticed agrieu1ture and laek of theuse of commereial fertilizers and manure.7. The amound of earbonate inresearch area soils changes between0,00 % and 38,24 %',8. Soil permeabiliteas are between1,1 cm/hour and 42,8 cm/hour. Thissoils will not create d drainage problembecause of having a good conduetivity.9. Infiltration rates are between0,6 cm/hour and 18,0 cm/hour. 40-100minutes ipass until infiltratian rates tomtes to reach the above values."a" and "n" values for the equation(y=a.t") whieh is ıısed to find thedepth of the soil that water penatratesare very differenL The value of "a"is betw~en 0,2078 and 1,9470, and thevalue of "n" is between 0,3721 and,0,8632.10. The moistı:ıre that is hold atdifferent sunetionf in profile layershave differences as a resuU of textureand organie matter. There is a positivecorrelation between available soil molstureand c1ay+silt, and c1ay+organicmatter.ll . .The ground and surface vaterwhieh is used for irrigation in theresearch area is in the class. of CıSıand CıSı and Only samJlle No. 7 wateris in the class of C 3S 1.As resuU of boron analysis; highconcentration of boron is found insome samples such 1,22 ppm in No.4, 1,81 ppm. No. 2 and 2,50 in No. 7.Plants resistant to boron should beraised if this high boron concentratedwater is used for inigation.12. Maximum water applicationrates are calculated as a function offield capacity and wilting poi~t for60 cm depth of soils and estimatedvalues differ between 3,2 cm and16,2 cm.13. Maximum water application rateswhich are computed for 60 cm.depth of soils require a time between4 min. and II hrs. 48 min. to infiltrateinto the soiI.14. The time required for the waterto reach to the end of the furrows in'the research area changes from i min.to 177 mın.i 5. When the irrigation is practiced· all over the research are, it is determinedthat following percentagesof the irrigable land wiıı be ıused toraise diffirent crops: 37 % for fieldcrops, 25,8 % for sugar beet, 12,5% for alfalfa, 8,1 % for potato, 3,8%for melons and contalaupes, 4,8 %for com and 3,8 % for pasture.Net annual water requirments of thecrops are computed by using BlaneyCriddleMethod and it is found 173,5mm. foı field crops, 220,0 mm formelons and contalaupes, 237,6 mm.for vegetable, 298,5 mm for com,362,6 mm for pastme grass, 412,2 mmfor sugar beet, 433,2 fOf alfalfa and462,4 mm for potato.Considerung the crops patternof the vaııey, net water requirement isfrom proshouldbe1and devei345,0 mm. Ifwater applieation efgieieneyis assumed about 40 %, annual waterrequirement .,of the valey is determined.as 862,5 mm if we consider the waterlass from irrigation ehannels; wa,terrequirment of the val1ey will be 880,0mm for Iined ehannel and 1044,1 mmfor eartb ditehes.16. Water resources of the valleyis not suffieient; therefore new' waterresources should be seeked and aneffective irrigation appIication which\\1ill have at least 60 % water applicationeffieeney should be practicedto have the maximum from tbe presentwater sources.17. Problems misingperty rights of the landcorreeted parallel to thelopment efforts.i 8. Needs of land leveling for theagrieu1tura1 land of this area as percentageof total are 35,22 %Iight, 4,53% medium and 0,75 % heavy.19. 10,86 %of the land has drainageproblem. Construetion of drainagesystem is not planned for the presentproject. Henee 1evel of water tableshould be ehecked carefully duringirrigation season.20. Experiments are made to findout the seepage lasses from to irriga,tion ehannels and it is found 1.17 %3,64% for conerete ehannels and forearth ditehes it has different valuesdepending on the texture of soli whichditches are located in; these values arecomputed 6,51 % in c1ay, 11,18 % inday-Idam, 18,82 % in silty clay, 19,88%in silty lo.am, 32,29 %loam grounds.21. A suitable rotation should bepraetieed to have the expected benefitwhen irrigation system is put in service.22. The most beneficial1y use ofthe established irrigation system willbe possible jf a management and maintaneeorganization with well trainedemployees is established.23. Farmers of this region arestragIy atteehed to their traditionstherefore they use a agrieu1tural systemwhich is very simple and for fromtodays modern techniques. They haveuncomplete or false knowledge aboutsoil tiliage, maint~nge fertilization andusing of better seeds. Henee farmersshould be trained in the short coursesby state agenties and university. Anextra effort should be made for extensionactivities to reaeh every farmerın the area.24. The cOst irrigation is 68,00TL. per dekar. 33 % of th'is amountis spent for eneıgy therefore electricityshould be sold to farmeıs withspecial rates to lower the cost of irrigation.