Soil-test biological activity with the flush of CO2: V. Validation of nitrogen prediction for corn production

Abstract

Production of corn (Zea mays L.) requires significant N availability to reach maximum yield potential. Nitrogen fertilizer recommendations generally have ignored site-specific conditions and have focused more on total N demand for representative soils across a region. Recent evidence suggested that site-specific conditions of the biologically active component (0–10-cm depth) could inform the magnitude of yield response to applied N fertilizer. This approach was tested further on 111 fields in Coastal Plain, Piedmont, and Blue Ridge regions (states of North Carolina, South Carolina, and Virginia). Plant-available N (sum of residual inorganic N and net N mineralization during a 24-d aerobic incubation) was inversely proportional to economically optimum N rate scaled to grain production level (r2 =.47, p