Effects of nitrogen fertilization on yield, profit and nitrogen absorption and utilization of spring maize

A field experiment was conducted to study the effects of nitrogen fertilizer application rates and methods on yield, profit, post-anthesis dry matter, N accumulation and translocation, nitrogen absorption and utilization of spring maize. The objective of this experiment was to make a scientific suggestion for high-yield management and N efficient utilization of spring maize. The results show that the yield and profit are increased by 3.91% and 592 RMB/ha under the reducing and postponing N application (RPN, N 240 kg/ha, 1/5 basal, 2/5 topdressing at the jointing stage and 2/5 topdressing at the bell-mouthed stage) compared with farmers practice (FP, N 280 kg/ha, 1/5basal and 4/5 topdressing at the jointing stage). The treatment of nitrogen fertilizer single basal application (SBN, N 240 kg/ha, total basal into 15 cm) has the best yield and profit, and the yield is increased by 11.48% and the profit is increased by 2032 RMB/hm2 compared with FP. In addition to these, the harvest index (HI), dry matter, nitrogen translocation and its rate, rate of contribution to grain, N use efficiency (NUE), agronomic N use efficiency (ANUE), N uptake efficiency (NUPE), N partial factor productivity (PFP) and N harvest index (NHI) were increased significantly (P0.05) under RPN and SBN treatments. The post-anthesis dry matter and N accumulation amount, and their ratios to the total are the highest under N240/3, are higher under N240/1, but the ratios are lower, and are lower under N2480/2, but the ratios are higher. There are many controversies on single basal application (SBN) of nitrogen fertilizer, so it could not conclude that SBN can be used to replace the farmers practice. It has got higher yield and N efficiency for the RPN treatment, so the reducing and postponing N application (RPN) is a scientific nitrogen fertilizer application method.