K. KILIC1, S. KILIC2 and R. KOCYIGIT3
1 Nigde University, Engineering Faculty, Department of Environmental Engineering, 51100 Nigde, Turkey
2 Ahi Evran University, Agricultural Faculty, Department of Soil Science, 40100 Kirsehir, Turkey
3 University of Gaziosmanpasa, Department of Soil Science, Faculty of Agriculture, 60240 Tokat, Turkey
KILIC, K., S. KILIC and R. KOCYIGIT, 2012. Assessment of spatial variability of soil properties in areas under different land use. Bulg. J. Agric. Sci., 18: 722-732
Land conversion from native ecosystem to agricultural use may alter soil physical, chemical and biological properties depending on duration and the type of tillage. The objectives of this study were to evaluate effects of duration of intensive cultivation practices (5 and 20 years cultivation) on some soil chemical and physical properties and to characterize spatial variability of soil properties. The study area is located at Kaz Lake of Tokat, Turkey. Soil pH, electrical conductivity (EC), cation exchange capacity (CEC), soil organic matter (SOM), total N, plant available P and soil texture were analyzed soil samples collected from a 5- and 20-year cultivated field converted from a native grassland. In addition, spatial variability of the soil properties under each land use were defined using statistical and geostatistical analysis. Soil pH had the minimum variability compared to other soil properties. Soil tillage (5 and 20 years of cultivations) caused significant changes in soil properties. Soil organic matter, total N, available P, CEC, and EC, clay content and silt content decreased significantly (p<0.01) while K+, Na+, pH and sand content increased with cultivation. The range of spatial dependence is between 9.6 and 310 m.
Soil variables with low nugget effect were defined by spherical model. The variables of the cultivated soils generally had a lower nugget than the variables of the native grassland. The degree of spatial dependence for CEC, clay, silt, sand and pH was low. The variation of the soil variables was fairly homogenized in the cultivated fields compared to the native grassland.