新型缓释尿素的缓释特性及其在土壤中转化研究

Release Characteristics of A New Slow-release Urea Fertilizer and Its Transformation in Soil

为探究基于改性基质材料研制的缓释尿素的氮素释放和形态转化特征,笔者通过室内淋溶和土壤培养试验,分析其氮素淋失、氨挥发及氮素形态转化特征。结果表明:砂柱淋溶试验中,普通尿素在第2次淋溶时氮素累积释放率达98.9%,而缓释尿素处理为62.4%。土柱淋溶试验中,缓释尿素前3次氮素淋溶量显著低于普通尿素处理,之后缓释尿素氮素淋溶量总体上高于普通尿素处理;缓释尿素累积氮素淋溶量(144.3 mg N)与普通尿素处理(146.9 mg N)无显著差异。缓释尿素和普通尿素处理的氨挥发速率均在第3天达到峰值,但缓释尿素可使氨挥发损失显著降低41.6%。尿素中的改性基质材料对氮素形态转化无明显影响。因此,该新型缓释尿素的作用机理主要是材料中的网状结构对养分的吸附而表现出具有保肥效果。

To explore the nitrogen release and transformation characteristics of a new modified host materialslow-release urea fertilizer,laboratory leaching and incubation experiments were conducted to analyze thenitrogen leaching,ammonia volatilization and nitrogen transformation characteristics.The results showed thatin leaching experiment,the nitrogen accumulation release rate of common urea fertilizer in the second leachingwas 98.9%,but that of the slow-release urea fertilizer was 62.4%.The nitrogen leaching amount of slow-release urea fertilizer was significantly lower than that of common urea fertilizer in the 1st-3rd leaching,andafter that the nitrogen leaching amount of slow-release urea fertilizer was significantly higher than that ofcommon urea.The cumulative nitrogen leaching amount of slow-release urea fertilizer（144.3 mgN） had nosignificant difference with that of common urea fertilizer（146.9 mg N）.Ammonia emission peaked at the 3rd day after fertilization in both common urea and slow-release urea fertilizer treatment,but cumulative ammoniaemission of slow-release urea fertilizer treatment was significantly decreased by 41.6% compared with that ofcommon urea fertilizer treatment.The modified matrix materials had no effect on nitrogen transformation; the mechanism was mainly attributed to the mesh structure of functional materials which could adsorb nutrientsuch as nitrogen.