Abstract: In order to investigate the effects of nitrogen fertilizer on yield and forage quality of silage maize and discus on more effective utilization efficiency of nitrogen fertilizer, using silage maize variety ‘Jinzhu 100’ as the test material, 5 nitrogen application levels of 0, 80, 160, 240 and 320 kg/hm² were set up and maize grain yield, the content of crude protein in stem, leaf and grain, the content of acid and neutral washing fiber and the content of starch under various nitrogen fertilizer treatments were determined. The test results showed that, the yield of corn was the highest at 240 kg/hm², reaching 11 044.28 kg/hm², and the yield increased by 11.82%. The content of crude protein and starch in maize stem, leaf and grain were the highest at 160 kg/hm², compared with the treatment without nitrogen fertilizer, it increased by 22.17%, 9.99%, 5.90% and 19.05%, respectively. The content of neutral washing fiber in seeds, stems and leaves were the lowest at 0 kg/hm² and 80 kg/hm²; when the nitrogen content were 0 kg/hm² and 160 kg/hm² the medium acid washing fiber of the stems and leaves were the lowest; when the treatment without nitrogen fertilizer, the medium-acid washing fiber in the grain was the lowest. In the application range of nitrogen fertilizer, the yield of corn was increased with the increase of nitrogen application. The forage quality of corn decreased with the increase of nitrogen application rate. While applying appropriate amount of phosphate fertilizer and potassium fertilizer to ‘Jinzhu 100’ corn, the yield and total dry matter weight were both the highest with 240 kg/hm² of nitrogen; From the perspective of quality traits, reducing the amount of nitrogen fertilizer application was an effective way to improve the forage quality of silage corn, and it was appropriate to use 160 kg/hm².

Key words: nitrogen fertilizer, silage maize, yield, forage quality