Dry Matter, Nitrogen, Phosphorus, and Potassium Accumulation Rates by Corn on Norfolk Loamy Sand1

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Abstract
The maximum amount and rate of nutrient accumulation by irrigated corn (Zea mays L.) must be known so that farmers do not waste money or pollute water resources by applying excessive amounts of fertilizer. Aerial whole plant samples were therefore collected from irrigated field experiments conducted on Norfolk (Typic Paleudults) loamy sand in 1980, 1981, and 1982, to determine seasonal dry matter, N, P, and K accumulations for corn yielding 10 Mg ha−1 or more in the southeastern Coastal Plain. Rates of accumulation were derived by differentiating compound cubic polynomial equations that described seasonal accumulation patterns. Total dry matter accumulation averaged 23.1 and 24.9 Mg ha−1 for two population treatments that averaged 7 ✕ l04 or 10 ✕ l04 plants ha−1. Aerial N, P, and K accumulation respectively averaged 228, 58, and 258 kg ha−1 in 1980; 264, 37, and 372 kg ha−1 in 1981; and 225,37, and 335 kg ha−1 in 1982. Grain yields averaged 13.4, 11.7, and 10.9 Mg ha−1 in 1980, 1981, and 1982, respectively. Lower P accumulations in 1981 and 1982 were the result of lower grain yields that were apparently caused by excessive K accumulation. Calculated peak dry matter, N, P, and K accumulation rates were 650, 10, 1.6, and 28 kg ha−1 day−1 in this study, compared to rates of 247, 4.5, 0.6, and 3.2 kg ha−1, respectively, in previous midwestern studies. Peak accumulation rates during both vegetative and reproductive growth stages emphasize that cultural, nutrient, and water management practices must be coordinated to provide a minimum stress production environment for high corn yield.