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在滇池柴河流域,蔬菜地施用的氮肥通过径流、淋溶和氨挥发等途径向水体迁移,对周围水体质量有较大影响。通过盆栽试验比较了控释尿素(3个氮水平:0 mg N/kg土、280 mg N/kg土和320 mg N/kg土)与普通尿素(4个氮水平:0 mg N/kg土、280 mg N/kg土、320 mg N/kg土和400 mg N/kg土)施用在柴河流域土壤所表现出的肥料氨挥发和氮淋失特征。结果表明,两种氮肥所有施氮水平处理的氮淋溶量都显著大于氨挥发量。在两种施氮水平下(320 mg N/kg土和280 mg N/kg土),施用普通尿素产生的氨挥发量分别占施氮量的3.64%和3.57%,而施用控释尿素产生的氨挥发量分别占施氮量的3.64%和2.78%;施用普通尿素产生的氮淋失量分别占施氮量的14.38%(其中硝态氮占85.34%)和14.46%(其中硝态氮占95.70%),施用控释尿素产生的氮淋溶量分别占施氮量11.60%(其中硝态氮占91.05%)和8.37%(其中硝态氮占96.84%)。硝态氮淋溶可能是柴河流域蔬菜地肥料氮素向水体迁移的主要途径。随着施氮量的减少,控释尿素的氮淋失量显著下降,而普通尿素的氮淋失量差异不显著。相同施氮水平下,普通尿素氮淋失量显著大于控释尿素。由此可见,控释尿素主要通过减少氮淋溶途径来减少氮损失。减量施氮结合控释尿素的施用对控制该地区氮肥施用对水体污染具有实际的指导意义。
In Dianchi Lake Chai River Basin, nitrogenous fertilizers applied to vegetable fields migrated to water bodies through runoff, leaching and ammonia volatilization, which had a great impact on the quality of surrounding water bodies. The effects of controlled release urea (3 N levels: 0 mg N / kg soil, 280 mg N / kg soil and 320 mg N / kg soil) and conventional urea (4 N levels: 0 mg N / kg soil , 280 mg N / kg soil, 320 mg N / kg soil and 400 mg N / kg soil) on ammonia volatilization and nitrogen leaching in the soils of the Chaihe River. The results showed that the nitrogen leaching amount of all the two nitrogen fertilizers was significantly greater than that of ammonia volatilization. Under the two nitrogen application levels (320 mg N / kg soil and 280 mg N / kg soil), the ammonia volatilization produced by application of common urea accounted for 3.64% and 3.57% of the nitrogen application, respectively. However, Ammonia volatilization accounted for 3.64% and 2.78% of the nitrogen application rates, respectively. The amount of nitrogen leaching loss by common urea accounted for 14.38% (of which nitrate was 85.34%) and 14.46% (respectively) 95.70%). The amount of nitrogen leaching produced by controlled release urea accounted for 11.60% (including nitrate of 91.05%) and 8.37% (of which nitrate was 96.84%) respectively. The leaching of nitrate nitrogen may be the main way of nitrogen migration from vegetables to water bodies in the Chaihe catchment. With the decrease of nitrogen application, the leaching loss of controlled release urea decreased significantly, but the difference of nitrogen leaching loss of common urea was not significant. Under the same nitrogen application level, the leaching loss of common urea nitrogen was significantly greater than that of controlled release urea. Thus, controlled release urea mainly through the reduction of nitrogen leaching route to reduce nitrogen losses. The application of reducing nitrogen fertilizer combined with controlled release urea has a practical guiding significance for controlling the nitrogen fertilizer application in this area to the water pollution.