An Algorithm to Determine the Optimum Tillage Depth From Soil Penetrometer Data in Coastal Plain Soils

Soil compaction is a significant problem in the southeastern Coastal Plain soils. Cone penetrometers are usedwidely for soil strength measurement and tillage decisions. However, there is no standard or comprehensive method fordetermining the optimum tillage depth from soil penetrometer data in Coastal Plain soils. Our objective was to develop analgorithm for determining the optimum tillage depth from soil cone penetrometer measurements to effectively remove thehardpan. Intensive geo-referenced soil cone penetrometer measurements were obtained and each cone index profile wasgraphically examined. The results showed six main patterns for penetrometer profiles in a Dothan loamy sand soil. Analgorithm and computer program was developed to determine the optimum tillage depth from the penetrometer data takenin a two-year study (2000 and 2001). The results clearly indicated that the thickness and the location of the hardpan can bedetermined from the soil cone penetrometer data. A great amount of variation was observed in the depth and the thicknessof the hardpan (4 to 25 cm) as well as in the optimum tillage depth (25 to 45 cm) in both years.