Abstract:

The excessive application of nitrogen and other chemical fertilizers is one of the main problems faced by China's agriculture and environmental fields. Exploring fertilizer reduction technologies which were suitable for regional promotion, and improving the utilization efficiency of nitrogen fertilizers, is of great significance. On this regards, this study used the early rice variety Zhongzao 39 as the experimental material and a field experiment was conducted. The effects of treatments including no fertilization (CK), no nitrogen application (N0), conventional fertilization (CG), and optimized fertilization (YH) on early rice yield, nitrogen uptake, and nitrogen utilization efficiency were studied. The results showed that there was no significant difference in rice yield between CK and N0 treatments, and there was no significant difference in yield between CG and YH treatments, while they were significantly higher than in CK and N0 treatments; Compared with CK, CG and YH treatments increased rice yield by 115.96% and 90.55%, increased straw yield by 95.32% and 67.89%, and increased N content in grains by 31.0% and 33.7%, respectively. CG and YH treatments increased N uptake in rice grains by 1.8 and 1.5 times, respectively; The nitrogen fertilizer utilization efficiency of rice treated with CG and YH was 40.90% and 43.08%, respectively; Compared with CK, there were no significant changes in soil pH, organic matter, and total nitrogen content under different fertilization treatments. This study indicates that N is the determining factor affecting rice yield, and under current experimental conditions, applying coated urea and reducing nitrogen fertilizer application by 20% can achieve stable rice yield.

Key words: fertilizer reduction, fertilizer utilization rate, encapsulated urea, rice yield, nitrogen uptake