Long term effects of lime and micronutrients on soil and leaf analysis and yield of soybeans grown on a Greenville soil

Abstract

Soil pH has a marked effect on the availability of micronutrients, but information is somewhat limited on soil pH and micronutrient interaction effects on soybeans. A 5‐year study, involving lime and micronutrient treatments, was conducted on a Greenville sandy clay loam (Rhodic Paleudult) to study the effects of these variables on soybean yield and leaf composition. Lime was applied at the initiation of the study (1970) and micronutrients were applied annually. Dolomitic limestone rates of 2240, 4480, and 8960 kg/ha increased the initial soil pH (6.1) .3, .6, and .8 units, respectively. Over the 5‐year period, one application of 2240–4480 kg/ha maintained the soil pH between 6.0 and 6.5. Extractable P, K, B, Cu, Mn, and Zn were not affected by increased soil pH, but extractable Ca and Mg were increased. Increases in soil B, Cu, and Zn were obtained by application of the element, however, in general two or more applications were required before increases were reflected by soil tests. Leaf B, Cu, Mg, N, P, and K concentrations were not affected by changes in soil pH. Conversely, leaf Ca concentration was increased and leaf Mn and Zn were decreased by increased soil pH. When B, Cu, Mn, and Zn were applied to the soil, increases in leaf concentration were detected only for B and Zn and this increase was obtained the first year of the study. Soybean yields were not affected by lime or micronutrients, indicating that soil pH and micronutrients (B, Cu, Mn, Mo, Zn) were not limiting factors in soybean production.