Optimizing Nitrogen Fertilizer Management Enhances Rice Yield, Dry Matter, and Nitrogen Use Efficiency

Abstract

Optimizing nitrogen fertilizer management can effectively improve soil ecology, promote agricultural production, and increase the income of farmers and workers. Nitrogen fertilizer is an important factor in the growth and development of rice, and it is important to find out the optimal amount and frequency of fertilizer application for the super-hybrid early rice ‘Zhu LiangYou 819’ in Hunan Province, to give full play to its high quality and high yield characteristics. Various N fertilizer application frequencies (P1, basal–tiller fertilizer = 5:5; P2, basal–tiller–spike fertilizer = 4:3:3; P3, basal–tiller–spike–grain fertilizer = 4:3:2:1) and N application amounts (N1, 90 kg ha−1; N2, 150 kg ha−1; N3, 210 kg ha−1) were applied to the hybrid rice ZLY819. The results show that, under the same frequency of N application, ZLY819 had the highest yield, agronomic efficiency, and physiological utilization rate of N fertilizer with the N2 treatment, averaging 7.53 t ha−1, 18.10 kg kg−1, and 34.34%, respectively, with the yield under N2 being 19.38% higher than that under N1. For the same amount of N application, the yield, agronomic efficiency, partial factor productivity of N (PFPN), N contribution to seed, and N use efficiency (NUE) increased with an increase in the frequency of N application, mainly in the order of P3 > P2 > P1, whereby the yield of P3 was 10.11% higher than that of P1. According to the regression equation, the yield is higher when the amount of nitrogen application is 202.15 kg ha−1 and the fertilization frequency is four times. Appropriate N fertilizer management (P3N2) improved the rice growth characteristics, dry matter accumulation, crop growth rate, dry matter transport rate, dry matter contribution rate, and NUE, thus promoting an increase in the rice yield and efficient use of nitrogen.