Reduced application and different combined applications of loss-control urea on summer maize yield and fertilizer efficiency improvement

Abstract

<p id="C3">Loss-control urea with nanometer mineral loss control agent added during production period could reduce the loss of nitrogen (N) through adsorption. Figuring out the application rate of loss-control urea and the appropriate rate with conventional urea could provide evidences for summer maize one-time fertilization, N fertilizer reduction, and use efficiency improvement. Under different yield level soil conditions, field experiment was arranged to investigate the effects of different N fertilizer managements on summer maize yield, aboveground biomass, nutrient accumulation, photosynthetic characteristic, and N utilization efficiency. Treatments of conventional urea (N at 210 kg hm^-2), loss-control urea (full dose with N at 210 kg hm^-2, 10% reduction with N at 189 kg hm^-2, and 20% reduction with N at 168 kg hm^-2), and different combined proportions of loss-control urea and conventional urea (at 7:3, 5:5, and 3:7) were carried out. The results revealed that N fertilizer application could significantly increase the yield of summer maize and the full-dose loss-control urea treatments increased the yield by 22.96%-27.55%, compared with that under conventional urea application at high- and middle-yield soil conditions. The application of loss-control urea at 10% and 20% reduction sustained the summer maize yield at high- and middle-yield soil condition with improved grains per ear, compared with full-dose loss-control urea application. The N fertilizer utilization efficiency under loss-control urea at 20% reduction treatment at high-yield soil condition reached 41.60%. N accumulation was comparable with full-dose loss-control urea application under proportions of loss-control urea and conventional urea at 7:3 application. Meanwhile, this treatment could sustain the yield and straw biomass at high- and middle-yield level soil and significantly increased the yield and straw biomass at low-yield field. In conclusion, one-time application of loss-control urea with N at 210 kg hm^-2 could significantly improve the yield of summer maize and N efficiency of the fertilizer utilization. The application of loss-control urea with 20% reduction could sustain the summer maize yield with significantly improved N utilization efficiency at high- and middle-yield soil conditions, which was the suitable N fertilizer application for high- and middle-yield field. Loss-control urea and conventional urea at 7:3 application was suitable for N fertilizer application for low-yield field.