Estimating consistency limits and maximum soil water content for soil tillage

Soil tillage is a reflectance of combine effects of mechanical effects of agricultural machineries and soil structure as affected by soil texture, moisture content and organic matter. Evaluating negative effects of soil tillage practices is important for sustainable soil management. The main goals of this study were to evaluate physical and mechanical properties of soils and to estimate optimum soil water content for cultivation using the preferred models in literature. For this purpose disturbed soil samples collected from 0-20 cm soil depth at 20 different locations were used. Soil texture, organic matter, soil reaction, lime content, consistency limits and soil moisture characteristics were determined. The relationships among the studied soil characteristics, plasticity and the plastic deformation as well as the methods used for prediction of maximum water content for soil cultivation were studied. Eleven out of 20 soil samples used in this study had clay, 7 clay loam and 2 sand clay loam texture. Soils had moderate amounts of organic matter with slightly alkaline soil reaction. It was obtained that soils had high resistance against water and mechanical forces in regarding with plastic deformation. It was suggested that soil moisture content at 0,9PL or near to 1,15 of consistency index should be considered as the maximum water content for appropriate soil tillage practices in order for sustainability of soil structure.