West Lafayette, Ind. — Soil nitrogen left behind by Indiana’s drought-stricken 2012 corn crop could mean that the state’s wheat growers might be able to apply less fertilizer this spring, according to a group of Purdue Extension agronomists. In a new publication, Carryover Nitrogen – Potential Impact on Wheat Fertilization, Shaun Casteel, Jim Camberato, and Chuck Mansfield discuss how corn plants stressed by extreme heat and too little water yielded less grain and left more nitrogen in soils than in normal years. "Spring fertilization rates necessary to optimize yield may be lower than what is needed following normal corn crops," Casteel said. "Wheat planted in the fall has an advantage in that it will accumulate some nitrogen prior to dormancy. Wheat’s primary advantage is the established root system that can take up nitrogen in the early spring before corn is even planted." In a more normal year, leftover nitrogen is removed from the crop root zone because of winter and spring precipitation, which typically totals 18-24 inches from October and April, Camberato said. This year, parts of Indiana have received less rainfall, particularly in the northeastern and northwestern parts of the state, where rain has ranged from 10-20 inches. Nitrogen carryover potential is much higher in these regions than in southern Indiana, the authors said. The full report is available for free download at http://www.agry.purdue.edu/ext/soilfertility/news/carryovernitrogenwheat.pdf.
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