Effects of partial mineral nitrogen substitution by organic fertilizer nitrogen on the yields of rice grains and its proper substitution rate

pplication of mixed mineral and organic fertilizers can ensure sustainable agriculture development. Field experiments were carried out to study the effect of partial mineral nitrogen (N) substitution by organic N on the yields of rice grains, N use efficiency and soil mineral N. The results obtained were listed as follows: 1) Application of mixed mineral and organic fertilizers resulted in a higher yield of rice (8381–10124 kg/ha) compared to single application of mineral fertilizer (8381–9810 kg/ha); 2) Substitution of 10-20 percentage of inorganic N, corresponding an application of 1500–3000 kg/ha of common compost organic fertilizer, was recommended when the nitrogen application rate was lower than 240 kg/ha because the rice grain yield, N use efficiency and economic benefits were highest under such condition；3) Compared with inorganic fertilizer treatment, application of mixed mineral and organic fertilizers maintained a steady supply of nitrogen, consequently improved the capability of soil nitrogen supply.