Field Scale Spatial Variability of Soil Physical Properties in the Harran Plain

Abstract

This study aimed to model the spatial distribution of surface and subsurface soil physical properties at a small field scale (12 hectares) in the Harran Plain, to estimate and map values at unsampled points. Geostatistical methods and mapping techniques were used for modeling, estimation, and mapping. Soil samples were collected at 54 separate points in the study area, representing disturbed and undisturbed samples from depths of 0-10 cm and 10-20 cm. Soil samples were analyzed for texture, aggregate stability, bulk density, available water content (AWC), water filled pore space (WFPS), and total porosity. The clay content of the study area soils ranged from 52 % to 69%, with the highest clay content observed in the western part and sporadically along the northern boundary. Aggregate stability values ranged from 11 % to 50 % in the top 20 cm depth, bulk density values ranged from 1.08 g cm^-3 to 1.48 g cm^-3, and AWC values ranged from 3.8 % to 13.6 %. While WFPS values in the southwest part of the study area were below 60%, they were above 60% in almost all other areas. Both surface and subsurface soils exhibited relatively low variability (CV<15 %) in clay and silt content, bulk density, field capacity moisture content, and WFPS, indicating relative homogeneity across the study area for these properties. Total porosity and microporosity CV values were also low at both 0-10 cm and 10-20 cm depths, indicating homogeneity in the water and nutrient retention and storage capacity of the study area soils at both depths. The information obtained will contribute to the optimization of field management and soil conservation practices, enhancing the sustainability of agricultural production.