Effects of subsoiling and N fertilizer application on dry matter accumulation, nitrogen use efficiency and yield of summer maize

To provide the basis for the highyield summer maize cultivar, field experiments were conducted to study the effects of subsoiling and controlled release urea on nitrogen accumulation, distribution and use efficiency and yield of summer maize in 2010 and 2011．Two sets of treatments were arranged in a split plot design．The wholeplot treatment factor was two tillage methods, rototilling for stubble breaking and subsoiling after rototilling for stubble breaking, and the subsubplot treatments are the N 225 kg/ha controlled release urea treatment, the N 225 kg/ha conventional urea for two applications treatment (40% was used as basal application and 60% was used at the beginning of male tetrad stage)，the N 225 kg/ha conventional urea treatment for one application and no nitrogen fertilizer treatment used as control．The maize cultivar, Zhengdan 958, was chosen as experiment material．The results show that in the same cultivation measure conditions，the trends of the nitrogen accumulation and distribution into the grains of all treatments are the controlled release urea treatment the conventional urea for two applications treatment the conventional urea treatment for one application the no urea treatment．Compared with the rototilling for stubble breaking, the subsoilling could increase the dry matter accumulation, nitrogen accumulation and distribution into the grains under the same nitrogen level．The yields and nitrogen use efficiencies of Zhengdan 958 in the two years are highest under the subsoiling and controlled release urea treatment, and are significantly higher than those of the other treatments．It is thus clear that the combination of subsoiling and the application of controlled release urea could provide an approach for using the nitrogen efficiently and getting higher maize yield．