Çukurova'da flüviyal tarım arazisinde bazı toprak verimlilik özelliklerinin jeoistatistiksel modellemesi

Toprak ortusu cok genis alanlari kapsar ve ozellikleri hakkinda bilgi, ornekleme yolu ile saglanir. Toprak ozelliklerindeki mekânsal degiskenlik, farkli mekânsal olceklerde, farkli sureclerin etkilesiminden kaynaklansa da, birbirinden farkli veya benzer ozellikte olabilmektedir. Sonuc olarak toprak ozelliklerindeki mekânsal degiskenlik, bircok farkli olcekte ve cozunurlukte, milimetreden birkac kilometreye kadar degisim gosterebilir. Tarim alanlarinda toprak verimlilik ozelliklerinin mekânsal degiskenliginin bilinmesi, optimum bir isletimle verimliligin gelistirilmesi acisindan onemlidir. Bu arastirma Cukurova'da her yil misir ekimi yapilan bir tarim arazisinde, 38 ha'lik bir ciftci tarlasinda gerceklestirilmistir. On bir toprak ozelligi [toplam N (tN) (mg kg-1), alinabilir P (aP) (mg kg-1), alinabilir K (aK) (mg kg-1), OM (%), EC (dS m-1), pH, KDK (cmol kg-1), kum (%), silt (%), kil (%), CaCO3 (%)] icin yapilan bu arastirma uc bolumden olusmaktadir: Birinci bolumde toprak ozelliklerinin farkli araliklarda (12,5, 25, 50, 100 m) yapilmis orneklemeleri kullanilarak mekânsal bagimlilik yapilari belirlenmistir. Ikinci yil ekim ve gubreleme oncesi donemi icin ayni ornekleme sistemi ile alinmis olan toprak ornekleri ile tN, aP, aK, OM ve EC'nin jeoistatistiksel modellemelerinin dogrulamasi yapilmistir. Calisilan arazide aP izotrop bir yapi gosterirken diger toprak ozellikleri yone bagli farkli azimut acilarinda anizotropik bir yapi sergilemislerdir. EC ilk yil I. donem tam kontrolsuz etki varyansi gostermis, ancak ikinci yil yone bagli anizotropik bir yapi sergilemistir. Mekânsal bagimlilik en yuksek kil ve KDK'da gorulurken en dusuk aP ve pH'da gorulmustur. En yuksek yapisal uzaklik major 576m, minor 468 m ile OM'de, en dusuk yapisal uzaklik ise major 245 m, minor 180 m ile siltde gorulmustur. Ikinci bolumde dinamik toprak ozelliklerinin (tN, aP, aK, OM, EC) farkli ornekleme donemlerindeki mekânsal degisimleri (mekânsal-zamansal) irdelenmis ve degisim oranlari belirlenmistir. Toprak ozelliklerinden ozellikle aK, tN, ve OM'de krigleme mekansal dagilim yapilarinin tum tarimsal uygulamalara ve diger dis etkenlere ragmen korundugu gorunmustur. Tarimsal uygulamalar, bazi toprak ozelliklerinin krigleme mekânsal yapilarinda, bitki gelisim surecinde onemli degisiklikler olustururken, ekim oncesi ve hasat sonrasi ornekleme donemlerinin mekânsal dagilim yapilarinda onemli benzerlikler gorulmustur. Ucuncu bolumde ise cok degiskenli (multivariate) mekânsal analizler yardimi ile toprak ozelliklerinin birbirleri ile olan iliskileri incelenmistir. Kil aK, OM, tN, KDK ve kum bir araya gelerek, temel bilesen analizinde toprak verimliligi bileseni olarak adlandirilan 1. bileseni olusturmus ve ayni toprak ozellikleri grubu birinci bilesen varyans faktor degerlerinin yuzeyi ile benzer krigleme mekânsal dagilim yapisi gostermistir.AbstractSoil covers large areas on the ground and information about its properties is provided by sampling. The spatial dependence structure of the soil properties can be similar or different among each other, even if they are affected by interactions of the different processes in various scales. As a consequence, the spatial variability of the soil properties may vary along with lots of different scales and resolutions which can be from millimeters to kilometers. It is important, in terms of yield improvement, to understand the spatial and temporal variability of soil fertility properties in agricultural areas. This research performed in a farmer land where maize is planting every year in Cukurova, Southern part of Turkey. The research, performed for 11 of soil properties [total N (tN) (mg kg-1), available P (aP) (mg kg-1), available K (aK) (mg kg-1), OM (%), EC (dS m-1), pH, CEC (cmol kg-1), sand (%), silt (%), clay (%), CaCO3 (%)], comprised of 3 stages. At the first stage, the most proper sampling interval and the most accurate spatial distribution of the soil properties studied by determining spatial dependence structures of the soil properties in different sampling intervals. The soil samples, collected for the second year in the same strategy of the first year, modeled geostatistically again in order to verificate the variogram model parameters of the first year for tN, aP, aK, OM and EC. While aP had isotropic variogram structure, other soil properties showed anisotropic variogram structure within different azimuth angle. EC had pure nugget effect at the first year sampling, but it showed anisotropic structure at the second year?s. The highest spatial dependence was observed in the geostatistical model results of clay and KDK, while the lowest was observed of aP and pH. While the longest spatio-structural range obtained from OM average value for major 550 m and minor 445 m, the shortest spatio-structural range obtained from silt for the major 245 m and minor 180 m. The temporal impacts, coming from either agricultural practices or other effects, on the spatial variability of dynamic soil properties (tN, aP, aK, OM, EC) examined at the second stage. The kriging spatial distribution structures, especially, of aK, tN and OM, did not change despite the all agricultural practices and other effects at the field. There was strong similarity between the kriging spatial distributions of pre-plant and past-plant periods, while some spatial distribution differences were obtained during plant growing periods. The relationships among the soil properties were studied by using multivariate spatial analysis at the last stage. Clay, aK, OM, tN, CEC and sand were gathered as the first component, which are of soil fertility parameters, in the principle component analysis (PCA) and the (PCA) analysis of this soil properties pointed out a similar spatial variability distributions as well.