Nutrient Concentration in Corn and Grain Sorghum Tissue as Related to Soil Type, Moisture Regime, and Growth Stage

Experiments were conducted to determine the effects of soil type, moisture regime, date of planting, and stage of growth on the nutrient content of corn and grain sorghum tissue. Early and late plantings of the two crops were grown on 12 soils (at six locations) encompassing wide ranges of chemical and physical properties. On five soils (at three locations), irrigation treatments were included. Corn and sorghum tissue samples were collected at three stages of growth (when corn was at eighth to tenth leaf stage, early tassel, and early silking) and analyzed for Ca, Wg, K and P concentrations. In general, K decreases and Ca and Mg increases occurred during the growing season. Some early plantings were higher in K and P than late plantings but the results for Ca and Mg were not consistent. Corn contained higher percentages of Ca, Mg and K than sorghum, but no conclusive crop difference was observed in the case of P. In most cases, concentration differences of Ca, Mg and K within plants grown on different soils appeared to be influenced more by the exchangeable K levels of the soils than by their exchangeable Ca and Mg levels. When P concentration differences occurred, higher levels were found in plants grown on soils with higher available P levels. Few differences resulted from irrigation treatment, and most could be attributed to the effect of higher moisture levels in favoring uptake of K over that of Ca and Mg, and by the effect of moisture on diffusion of P.