关键词: 水稻, 聚脲甲醛缓释肥, 一次性施肥, 氮肥利用效率, 产量

Abstract:

【Objective】 This experiment was carried out to study the effect of one-off application of poly urea- formaldehyde fertilizer with reduced N rate on double rice and to explore the possibility of one-off application of poly urea- formaldehyde fertilizer on double rice, thus providing a theoretical basis for simple and easy, synergistic and less nitrogen fertilizer practice, so as to increase fertilizer efficiency, and reduce the non-point source pollution.【Method】The conventional rice variety “Jingxiang Simiao” was used in a field experiment. One year field experiment, including early rice and late rice, was conducted. Under the conventional total N input of 180 kg·hm^-2, the one-off application of poly urea-formaldehyde fertilizer with reduced 0, 23%, 38% and 47% N rate (UF1, UF2, UF3 and UF4, respectively), conventional fertilization (CF, 50% of base fertilizer, 20% of turning green fertilizer and 30% of elongation fertilizer), and no nitrogen fertilizer (CK) were designed. All the experimental fields were fertilized with P₂O₅ 55 kg·hm^-2 and K₂O 130 kg·hm^-2, which were supplied by calcium superphosphate and potassium chloride. Research mainly focused on the influence of one-off application with reduced N rate on the yield, biomass, NPK contents of the above-ground portion, nitrogen use efficiency of rice, and the inorganic nitrogen content in soil. 【Result】(1) There were no significant differences in the grain yields of early and late rice among CF, UF1, and UF2 treatments. The grain yield of early rice under UF3 treatments reduced significantly by 7.52% comparing with CF treatment (P<0.05). The grain yield of early and late rice under UF4 treatment all decreased significantly by 9.84% and 9.75%, respectively, comparing with CF treatment (P<0.05). (2) Comparing with CF treatment, the effective panicles per hill for early rice and late rice in treatment UF4 were 0.80 and 0.39 less, while the decrease during early rice had reached significant level (P<0.05). UF1, UF2 and UF3 treatments had the similar effective panicles, filled grains per panicle, filled grain rate, and 1000-grain weight of early rice and late rice with CF treatment. (3) The contents and accumulations of N, P and K in the straw and grain of the early and late rice under UF1 and UF2 treatments were not significantly different from the CF treatment. While the content and accumulation of N in the straw of late rice under UF3 treatment were lower by 30.73% and 23.60% respectively than CF treatment (P<0.05). And the UF4 had the lowest N content, N accumulation of early rice and late rice, which were 22.82% and 26.82% less, respectively, than CF treatment (P<0.05). (4) Comparing with CF treatment, UF2, UF3 and UF4 treatments had increased partial factor productivity of N fertilizer by 24.37%, 49.24% and 70.89%, respectively (P<0.05). But no significant differences in the agronomic efficiency of N fertilizer, N recovery efficiency, and physiological efficiency of N fertilizer among all fertilization treatments were observed. (5) No significant differences in the available inorganic N content in soil after rice harvest between UF and CF treatments were detected, but the total N content in the soil was slightly higher than that under CF treatment. Therefore, poly urea-formaldehyde fertilizer could be used as the special slow release fertilizer in the one-off fertilization technology for early and late rice.【Conclusion】UF2 treatment, the one-off application of poly urea-formaldehyde fertilizer with reduced 23% N rate had obtained relatively high grain yield and nitrogen use efficiency in early and late rice seasons, and the cost of which was equal to CF. It was concluded that this fertilizer application method could be served as the an effective way to simplified fertilization and reduce N application in early and late rice cultivation.

Key words: rice, poly urea formaldehyde, one-off fertilization, nitrogen use efficiency, yield