Aerial Accumulation and Partitioning of Nutrients by Corn

Amounts and rates of dry matter and nutrient accumulation for very high-yielding corn (Zea mays L.) were unknown, but were needed to develop a base for future research and on-farm maximum economic yield demonstration programs. Aerial whole plant samples, collected from a maximum yield research experiment that resulted in a 19.3 Mg ha⁻¹ grain yield on a Typic Hapludult soil (Freehold sandy loam) near Adelphia, NJ, were used to provide that information. Samples were collected at growth stages V4, V8, V12, VT, Rl, R2, R5, and R6; separated into lower leaves, upper leaves, stem and tassel, and ear and shank fractions; and analyzed to determine N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn concentrations. Accumulation curves for each plant fraction were computed using those data and described mathematically using compound cubic polynomial equations. Dry matter and nutrient accumulation rates were computed by differentiating the equations. Total accumulation at physiological maturity was approximately 31 800, 386, 70, 370, 59, 44, 40,0.13,0.14, 1.9, 0.9, and 0.8 kg ha-' for dry matter, N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn, respectively. Distribution among the four plant fractions, as well as rates of accumulation, are discussed. Diagnosis and recommendation integrated system indices were calculated using leaf concentration data. Nutrient balance was very good, although fertilizer recovery was not optimum. Amounts and rates of accumulation measured in this study can provide general guidelines for very high corn yields when more economical practices are used. Contribution of the USDA-ARS, Coastal Plains Soil and Water Conserv. Res. Ctr., in cooperation with the South Carolina Agric. Exp. Stn., Clemson, SC, and the New Jersey Agric. Exp. Stn., Cook College, Rutgers Univ. This work was performed as part of NJAES Project no. D-15116-1-87, supported by the New Jersey Agric. Exp. Stn. and the Potash and Phosphate Inst.