Developing an Algorithm to Determine the Tillage Depth from Soil Penetrometer Data in Coastal Plain Soils

This study deals with developing an algorithm to determine the optimum tillage depth from soil cone penetrometer data in coastal plain soils. Intensive geo-referenced soil cone penetrometer measurements were obtained and each cone index profile was graphically examined. The results showed 21 different patterns or conditions for the soil cone penetrometer profiles in a Dothan loamy sand soil. An algorithm was developed to assess and find the optimum tillage depth. The limiting cone index value, which prevents the root development, was taken as 2.07 MPa (300 psi). After defining the algorithm, a computer program was written to automate the application of the algorithm for large data sets. The computer program was used to find the optimum tillage depth for the data taken in the two-year study (2000 and 2001). The results of the experimental study clearly indicate that the thickness and the location of the hardpan can be determined from the soil cone penetrometer data. A great amount of variation was observed in the location and the thickness of the hardpan as well as in the optimum tillage depth in both years.