Effect of Nitrogen Application Rate on Nitrogen Efficiency and Grain Yield of Red Rice Hybrid Rice

This study aims to investigate the effects of nitrogen application rates on the yield and nitrogen utilization efficiency of red rice hybrid rice. In 2024, a field experiment was conducted in Nan'an City, Fujian Province, using Shennong You Hongsimiao as the experimental material. Five nitrogen application levels were set: 0（CL1, CK）, 150（CL2）, 165（CL3）, 180（CL4）, and 195（CL5）kg·hm⁻². The experiment measured the yield, plant height, effective panicle number, grains per panicle, and grain filling rate of red rice hybrid rice under different treatments. The results showed that the yield of red rice hybrid rice increased with the increasing amount of nitrogen fertilizer applied, and different nitrogen fertilizer treatment levels significantly affected plant height, effective panicle number, and grain filling rate. The highest rice yield and agronomic efficiency occurred at a nitrogen application rate of 180.0 kg·hm⁻². However, the nitrogen utilization efficiency decreased as the amount of nitrogen fertilizer increased. These findings indicate that for the cultivation of Shennong Youhong Simiao in Nan'an City, applying 180.0 kg·hm⁻² of nitrogen can achieve both high yield and efficient nitrogen utilization.