Spatial Variability of Soil Penetration Resistance in an Alluvial Delta Plain Under Different Land Uses in Middle Black Sea Region of Turkey

Abstract

The aim of this study was to analyse the soil compaction and its spatial variability on an alluvial plain in Kzlrmak River Delta in Turkey, which is an important agricultural area where vegetable, rice, cereals and other crops have been grown under conventional tillage and irrigation over a long period. Penetration resistance (PR) was measured at 5cm depth intervals between 0 and 40cm soil depth, and gravimetric water content (GWC), field capacity (FC) and texture were determined for 0-20cm and 20-40cm. Penetration resistance values in some parts of the area were higher than the critical value for root growth limitation, the mean PR values at all depths were considerably lower than the critical value despite a relative increase in PR with soil depth. The areas with values greater than 3.0MPa, except for 0-5cm, were generally located in the fields with high sand content, especially near the Kzlrmak River. In contrast, for 0-5cm, the areas with PR greater than 3.0MPa, which is the value accepted for root growth limitation, were usually located in the west and northwest of the study area and had a high clay content.