Improving Lime Recommendations in West Virginia Pasture Soils

Rajesh Chintala, Louis M. McDonald and William B. Bryan

West Virginia University

 The success of a liming program is dependent on the accuracy of the lime recommendation, which in turn depends on the quality of the underlying correlations and calibrations. Due to the expense, large-scale field calibration experiments are rarely done anymore. The relatively low economic returns from pasture make it even more unlikely that a calibration experiment could be conducted. Therefore any improvements in lime recommendations have to be made from lime correlations. Soil test lime correlations are strictly valid only for the soils used to determine the correlation. There are approximately 177 soil series used in West Virginia belonging to six orders (59 Alfisols, 50 Ultisols, 41 Inceptisols, 19 Entisols, six Mollisols and two Spodosols) in four MLRAs. Given this range in soil types, it is unlikely that a single lime correlation can accurately identify appropriate lime rates for all soils. Ninety surface soil samples (0 – 7.5 cm) from each of three most important soil orders for the state (Alfisols, Inceptisols, Ultisols) from each of the MLRAs in West Virginia with large proportions of pasture land were collected in cooperation with state soil scientists. Many of these soils were collected as part of ongoing soil survey work in the state and so are point samples from control pedons. Standard procedures for the determination of lime requirements by the Mehlich Buffer (MB), Adams-Evans Buffer (AEB) and Shoemaker-McLean-Pratt Single Buffer (SMPB) methods were used. Equation-based lime correlations were determined by multiple regressions where the independent variables are target pH and soil-buffer pH. Optimal methods to group soils in the State were determined.