Charles C. Mitchell1, Donald M. Ball1, Jorge A. Mosjidis2 and Joyce Tredaway Ducar3, (1)Auburn University, Auburn University, AL (2)Auburn University, Auburn, AL (3)Crops, Soils, and Environmental Sciences, Auburn University, Auburn University, AL
Lespedeza cuneata is a popular, perennial legume forage crop in the southeastern U.S. often called “sericea”. No published, soil fertility research could be found with this crop. Two long-term soil fertility experiments on a Hartsells fine sandy loam (fine-loamy, siliceous, thermic Typic Hapludults) in Alabama were seeded to 2 cultivars of sericea in 2004 and monitored for 5 years. Soil fertility variables include N rates, residual soil P levels, K levels, soil pH, and soil Mg levels. All treatments produced a mean dry matter yield of 14 Mg ha-1yr-1 . Critical Mehlich-1 extractable P and K values for sericea on this soil were identified as 25 mg P kg-1 and 40 mg K kg-1, the same value as currently used in the Auburn University Soil Testing program. Although these data did not allow establishing a critical soil test pH value for sericea, we did observe significant yield decreases when the soil pH was below 5.0.