Effect of SODmN Reduction Application on the Yield, Profit and Nutrient Utilization of Spring Maize in Hexi Oasis Irrigation Area

PurposeIn order to find out the reduction degree of spring maize after replacement of ordinary nitrogen with new SODmN and the absorption and utilization of nitrogen.

MethodThrough the field plot experiment, with no nitrogen application (CK) and local traditional nitrogen application rate (CFN) as the control, the effect of equivalent nitrogen amount SODm nitrogen (SODmN), SODmN decrement 10% (SODmN−10%), SODmN decrement 15% (SODmN−15%), SODmN decrement 20% (SODmN−20%) and SODmN decrement 25% (SODmN−25%) on spring maize yield profit and nitrogen use efficiency was studied.

ResultsCompared with the CFN treatment, when the SODmN application rate was reduced by 15% and continued to decrease, the maize yield showed a downward trend. SODmN−15% treatment brought about relatively high grain yield and biological yield, and the maize yield first increased and then decreased with the increase in the degree of nitrogen reduction, showing a quadratic polynomial relationship. After fitting, the nitrogen application rate corresponding to the highest maize yield was 313 kg/hm², and the nitrogen application rate corresponding to the highest net income was 292 kg/hm². The total amount of absorbed nitrogen was manifested by increase firstly and then decrease. The nitrogen harvest index, nitrogen balance, and nitrogen use efficiency (except SODmN−25%) all increased with the increase in nitrogen reduction.

ConclusionThe fertilizing amount of maize in the Hexi oasis irrigation area was relatively high. After replacement of ordinary nitrogen with SODm nitrogen, significant nitrogen excess appeared. With the increase in nitrogen reduction, the yield of spring maize grains was manifested by a trend of first increase and then decrease. The yield began to decrease when the nitrogen reduction exceeded the conventional nitrogen application rate by 20%, but the nitrogen reduction within 25% did not cause a significant impact on maize yield. Replacement of ordinary urea N with SODmN on the basis of traditional fertilization can achieve the goal of reducing nitrogen rate by 20%, maximizing the yield benefit and significantly improving the nitrogen use efficiency.