IMPORTANCE OF SPATIAL SOIL VARIABILITY FOR LAND USE PLANNING OF A FARMLAND IN A SEMI-ARID REGION

Abstract

Assessing the spatial variability of soil properties is vital in proper planning of agricultural farmlands. The aim of this study is to determine and map the spatial variability of important physical and chemical soil properties using geoistatistical models for land use planning of a farm located in Thrace region of Turkey. Two hundred fifty-four surface and subsurface soil samples were collected from at approximately the corners of 150m x 150m size grids cells. The land area of study area was 557 ha and used for what and sunflower production. Soil samples were analyzed for particle size distribution, soil reaction (pH), electrical conductivity (EC), organic matter (OM), lime content (CaCO3), available phosphorus (P) and extractable potassium (K). Penetration resistance was also measured at each sampling point. Soil pH ranged from 4.46 to 8.20 in surface and 4.01 to 8.30 in subsurface soils. Sand content was the least variable (CV=11.5% and 13.9% for surface and subsurface) soil property, while the variability of P content (CV=105.9 and 119.8%) was higher than the rest of the soil properties. The lowest range value was obtained for P content (113 and 134 m) and the longest-range value was for available K content (5899 and 6099 m) of soils. Spatial distribution maps helped to identify and deliniate the zones need to be limed, deficient in available P and compacted zones within the study area. Sustainable management strategies in a farm can be planned and implemented using the information obtained from spatial structures and maps of major soil characterics.