| Rice is one of the most important food crops in China, and its production plays an important role in grain production. However, the production has problems of high application rate, low utilization rate, environment pollution and so on. In general, the application number of nitrogen fertilizer is 1-2 times so that it is a time-consuming and costly work. So it is necessary to search a technique that can simplify fertilization and obtain high yield. Controlled-release nitrogen fertilizer(CRNF) is a new type fertilizer which can control the releasing of nutrient. Due to its release regular and high price, it can't be promoted in China. Fyou 498 was as the material, effect of different CRNF and effect of different ratio of a screened CRNF with urea(UR) on rice growth, nitrogen uptake, yield and economic benefit was discussed in this study, and explore a optimal combined proportion, then provide a scientific basis and reference for abridgind cost and increase income. The main conclusions are as follows:(1) The result of controlled release nitrogen fertilizer screening test showed that:The addition of controlled release nitrogen fertilizer could increase the yield of 5.4%?12.9%, effectively improve the nitrogen utilization rate and the content of soil nitrogen. The effects of CRNF1 were best, and could for further research the effect of different combined ratio with urea.(2) The yield of CRNF combined with UR treatment was average 8.2% higher than that of CRNF only. The economic benefits were 178.42-2978.19yuan/hm2 and 619.59?3419.38 yuan/hm2 higher than that of CRNF only and UR only, respectively. And 40%CRNF+60% UR could achieve the highest economic benefit. The yield were 16.6% and 13.4% higher than CRNF only and UR only, economic benefit were 3419.38 yuan/hm2 and 2978.19yuan/hm2 higher than CRNF only and UR only.(3) CRNF combined with UR could improve the content of inorganic nitrogen. The nitrogen content with UR only and CRNF CRNF10%+UR90%, CRNF20%+UR80% were higher than that of others in early growth stage, while the content showed that CRNF+UR >CRNF?UR in mid-late growth stage. The nitrogen content could keep a high level with combined application in the whole growth period. And the content of inorganic nitrogen in topsoil was 68.1% higher than UR only.(4) CRNF combined with UR could significantly promote the growth of rice and improve the dry matter accumulation in mid-late growth stage. The plant height with combined application and CRNF only had no significant difference with UR only in early growth stage, while the plant height were higher than UR only in mid-late growth period. The dry matter accumulation showed that UR>CRNF+UR(except CRNF10%+UR90%)> CRNF in tillering stage, but CRNF>CRNF+UR>UR in mature period. So combined application could satisfy the demand of nitrogen in early growth stage, and is useful for growth in mid-late period. Combined application improve the dry matter accumulation of grain significantly, and the dry matter accumulation of grain with CRNF40%+UR60% was the highest,12.2% and 14.3% higher than that of UR only and CRNF only, respectively.(5) CRNF combined with UR could increase the nitrogen concentration, nitrogen accumulation, nitrogen use effiency and nitrogen translocation remarkablely. The nitrogen accumulation with high combined ratio of UR were higher than that of others in tillering stage. With the development of growth process, the nitrogen accumulation presented as CRNF+UR>CRNF>UR. The nitrogen accumulation of leaf was increased with the combined ratio of CRNF increasing in mid-late growth period, and the nitrogen accumulation of spike had the same change trend with the aerial part. Combined application improved the nitrogen accumulation of grain significantly. And CRNF40%+UR60% was the highest,16.6%,19.5% and average 10.4% higher than that of CRNF only, UR only and other combined treatments, respectively. The increase amount of spike with combined application were higher than that of UR only in heading stage to mature period, and reached significant level. Combined application improved the nitrogen utilization rate. The apparent utilization rate, agronomic efficiency, physiological use efficiency and partial productivity of nitrogen with CRNF40%+UR60% were the highest.(6) The application of CRNF combined with UR or CRNF only could decrease the concentration of nitrogen, ammonia volatilization flux and ammonia volatilization accumulation loss in paddy field. The ammonia volatilization accumulation loss of CRNF only was the lowest, and 22.46% lower than UR only.(7) Growth, soil nitrogen, nitrogen uptake, yield, economic benefit and ammonia volatilization were comprehensively considered, CRNF40%+UR60% was the best for promoting rice growth, improving nitrogen use effiency, decreasing ammonia volatilization and achieving high yield. |
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