Effects Of Application Of Organic-Inorganic Mixed Fertilizers On The Yields Of Rice Grains And Nitrogen Use Efficiency And Soil Nitrogen Supply

A field experiment was carried to study effect of application of organic-inorganic mixed fertilizers on the yields of rice grains, nitrogen use efficiency and soil mineral nitrogen. The rerults obtained are listed as follow.1 Application organic-inorganic mixed fertilizers could have a better or the same effects on the yields of rice grains compared with inorganic fertilizer treatment. Grain yields of two rice cultivars, 4007(8242 kg·hm^-2-10187 kg·hm^-2) and changyou No 1(10048 kg·hm^-2-11654 kg·hm^-2), for example, were increased when 180 kg·hm^-2 N was applied with a percentage of organic N in total N being 15%-30% or 240 kg·hm^-2 N with a percentage of organic N in total N being 10%-20%, which corresponds an application of 1500 kg·hm^-2-3000 kg·hm^-2 of common compost organic fertilizer. However, the yields of rice grains would decrease if the nitrogen application rate and the percentage of organic N in total N applied exceeded 240 kg·hm^-2 N and 20% or 30%, respectively. Application of pig manure compost and rapeseed cake compost mixed separately with inorganic fertilizers increased grains yields of 4007(8294 kg·hm^-2-9437 kg·hm^-2) and changyou No 1(9120 kg·hm^-2-9345 kg·hm^-2) to a larger extent than other composts mixed with inorganic fertilizer. All the treatments, except the CK, received the same cost.2 Application of organic-inorganic mixed fertilizers could increase dry matter accumulation at the late stage of rice growth significantly. Dry matter accumulation of 4007(13412 kg·hm^-2-18722 kg·hm^-2) and changyou No 1(17905 kg·hm^-2-21469 kg·hm^-2) was increased when 180 kg·hm^-2 N was applied with a percentage of organic N in total N being 15%-30% or 240 kg·hm^-2 N with a percentage of organic N in total N being 10%-20% compared only inorganic fertilizer treatment. Dry matter accumulation of 4007(13983 kg·hm^-2-15908 kg·hm^-2) and changyou No 1(14789 kg·hm^-2-16514 kg·hm^-2) in the application of mixed chemical fertilizer and different composts treatments was increased compared inorganic fertilizer treatment.3 Compared with inorganic fertilizer treatment, a more steady supply of nitrogen could be maintained when 180 kg·hm^-2 N was applied with a percentage of organic N in total N being 15%-30% or 240 kg·hm^-2 N with a percentage of organic N in total N being 10%-20%. Nitrogen accumulation of these treatments were separately 172.6 kg·hm^-2-256.4 kg·hm^-2(4007) and 185.9 kg·hm^-2-235.6 kg·hm^-2(changyou No 1). In these treatments, the highest nitrogen use efficiency was obtained in 4007(36.6%-48.1%) and changyou No 1(34.3%-40.0%). Application of mixed chemical fertilizer and different composts could get a better synchronization of soil N supply with the requirement of plants than inorganic fertilizer treatment. In these treatments, the highest nitrogen use efficiency was obtained in 4007(24.0%-37.5%) and changyou No 1(22.2%-33.0%). This demonstrates that all organic-inorganic mixed fertilizer treatments improved the capability of soil nitrogen supply.In conclusion, application of organic-inorganic fertilizers could improve the N nutrition of rice plants, thus increasing the rice grain yields and the economic benefits for growing rice plants.