Effects of different fertilizer combinations on the yield and nitrogen use efficiency of summer maize in Jiangsu Province, China

The rational application of nitrogen (N) fertilizer plays a crucial role in promoting crop growth and increasing yields. The application of slow-release fertilizer has emerged as an important agronomic measure to further increase yield and production efficiency. In this study, a field trial with the maize hybrid Jiangyu877 was conducted to investigate the effects of six fertilizer combinations [no fertilizer (P1), common N application (P2), slow-release N application (P3), common N and slow-release N 1:1 application (P4), 1:2 application (P5), and 2:1 application (P6)] on yield and nitrogen use efficiency (NUE). Fertilization significantly increased maize yield, with the greatest increase occurring in the treatment combining common and slow-release N. Among all the treatments receiving equal N amounts, the P5 resulted in the highest yield and NUE than the other treatments did. Compared with those in the P3, the dry matter accumulation of the P5 increased by 6.6-13.7%, the N accumulation increased by 13.0-16.3%, and the NUE increased by 8.1-11.5%. In addition, compared with those in the P3, the 1000-grain weight and number of grains per cob significantly increased, the yield increased by 2.6-4.5%, and the net income increased by 17.1-80.4% over the 3 years. In conclusion, in the summer maize production in Jiangsu Province, China, under a planting density of 75,000 plants ha^-1, the recommended fertilization method involves a one-time base application of common N and slow-release N (1:2, common N at 75 kg ha^-1: slow-release N 150 kg ha^-1) to realize synergistic improvements in yield and efficiency.