Subsoiling for Nitrogen Applications to Corn Grown in a Conservation Tillage System
1986
Reeves, D. W. | Touchton, J. T.
Subsoiling not only improves root penetration and water infiltration but may also provide an efficient means of applying N fertilizer. Field studies were conducted 2 yr on a Norfolk sandy loam (fineloamy, siliceous, thermic Typic Paleudults) and 1 yr on a Dothan fine-sandy loam (fine-loamy, siliceous, thermic Plinthic Paleudults) to determine the effect of N source and application method, subsoiling placement, and time of subsoiling and N application on the efficiency of N applied to no-till corn (Zea mays L.). Urea and NH₄N0₃ (157 kg ha−¹) were applied (i) surface-banded at planting, (ii) in the in-row subsoil track at planting, (iii) surface-banded 5 weeks after planting, or (iv) interrow with subsoilers 5 weeks after planting. Nitrification inhibitors, dicyandiamide (cyanoguanidine) (DCD) and ethylene dibromide (1-2-dibromoethane) (EDB), were also used with urea applied in subsoil tracks. Neither inhibitor affected grain yields. Applying N in the subsoil track proved an effective application method. Generally, highest yields (8204 to 9486 kg ha−1) were obtained by applying N 5 weeks after planting with in-row subsoiling. Results indicate no benefit to subsoiling interrow if in-row subsoiling was done at planting; however, if corn was planted without in-row subsoiling, subsoiling interrow 5 weeks later improved yields. Interrow subsoiling may be a practical alternate management tool, especially when used to apply sidedressed N, for growers in years when subsoiling at planting is not feasible.
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