Nitrification Inhibitor with Fall‐applied vs. Split Nitrogen Applications for Winter Wheat¹

Abstract

Since numerous small grain producers desire to make fall application of efficient levels of N for maximum yields, studies are needed to determine the efficiency of fall‐applied N (with and without an inhibitor) vs. split N applications. Field studies were conducted at two locations each year over a 3‐year period with the objective of evaluating the response of wheat (Triticum aestivum L.) to N rates, time of application, and effect of a nitrification inhibitor on soils of different characteristics (Typic Hapludult and Typic Paleudult). Yields, tissue concentrations of various elements, grain analyses, and soil NH4‐ and NO3‐N were evaluated. Splitting the N, 28 kg/ha in the fall and 56 kg/ha topdressed in the spring, was superior to applying all the N in the fall. The inclusion of the nitrification inhibtor, 2‐chloro‐6‐(trichloromethyl) pyridine (N‐Serve), with ammonium sulfate in the fall at the rate of 84 kg/ha did not influence yields or N levels in the tissue or grain. The inhibitor had no effect on elements other than N. Although the nitrification inhibitor influenced the retention of the NH4‐N in the soil until the January sampling, this retention was not evident for either soil at the March sampling. Therefore, we concluded that the N applied as a part of the complete fertilizer at the rate of 28 or even 84 kg/ha in the fall is inadequate for maximum wheat yield in either the coastal plain or piedmont regions of Georgia. A nitrificaton inhibitor applied with the ammonium sulfate was ineffective in preventing nitrification of the ammonium nitrogen or to increase yields.

Comparison of nitrification inhibitors to restrict nitrate leaching in a maize crop irrigated under mediterranean conditions

“…In such cases, the strategy was to hold ammonium in the soil thereby retarding its oxidation to nitrate. The use of nitrification inhibitors may offer an alternative to splitting N applications (Boswell et al, 1976) in order to improve the efficiency of applied N.…”

Variation of Soil Dielectric Constant, Moisture Holding Capacity, and Nitrate-Nitrogen as Influenced by Application of Fresh and Compost Poultry Litter on a Decatur Silt Loam Soil

“…Comparison between treatments with and without CMP indicated that inclusion of CMP with treatments had no significant effects on improving the cotton yields at any rate of application studied. Previous studies have revealed that the effects of nitrification on crop yields depended on soil, climatic conditions as well as management practices (Boswell et al, 1976;Rao, 1996).…”

Residual Maize Fertilizer Nitrogen Availability to Wheat on the Southeastern Coastal Plain

“…Even though a dry winter followed the second season, adequate summer rainfall allowed good maize yields and utilization of N fertilizer by the maize. Substantial wheat yields with no or limited N application have been obtained in Coastal Plain soils in certain situations, indicating significant N carryover from one crop to the next (Camberato, 1990, unpublished data;Boswell et al, 1976;Gravelle et al, 1988). More extensive experimentation as well as water use modeling should be employed to determine the potential for N carryover from one crop to the next in the Coastal Plain environment.…”