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淋洗作用是土壤氮肥损失途径之一,也是环境水体氮素污染的重要途径。研发降低土壤氮素淋失的技术途径不仅有助于提高氮肥利用率和降低化肥的施用量,而且有助于防治水体污染和改善生态环境。本文通过淋滤实验研究了生物炭对我国两种重要土壤类型黒钙土和紫色土氮素淋失的影响。由玉米秸秆制成的生物炭按10 t/ha,50 t/ha,100 t/ha的比例施用于土壤,同时模拟田间尿素施用量240 kg.N/ha并用相当于每天10 mm的降水量用去离子水淋洗土壤。对淋滤液氮素组成和含量分析结果显示,在不施用生物炭的条件下,黒钙土和紫色土总氮的淋失量分别占土壤(土壤+尿素)总氮含量的7.5%和9.0%,氮素的淋失主要发生在前130 mm降水过程中,其淋失量占全部淋失量的96%。在淋失的成分中,除硝态氮外,有机氮也是重要的组成物质,二者均占淋失总氮量的48%。生物炭的施用可以大幅度地降低氮素的淋失作用。50 t/ha和100t/ha的生物炭施用量降低黑钙土氮素淋失分别为29%和74%,减少紫色土氮素淋失分别达41%和78%。但10 t/ha的生物炭施用量却增加黒钙土和紫色土氮素淋失量分别达到22%和2%。这表明较低的生物炭施用量会促进氮素的淋失。生物炭对有机氮淋失的抑制作用大于硝态氮。100 t/ha的生物炭施用量对有机氮和硝态氮淋失的降低率分别为88%和62%左右,因土壤类型不同而有所差异。上述研究结果为寻求防治土壤氮素淋失的技术方法提供了理论依据。
Rinsing is one of the ways of soil nitrogen loss, and also an important way of nitrogen pollution of environmental water body. Research and development to reduce soil nitrogen leaching technology approach not only helps to improve nitrogen fertilizer utilization and reduce the amount of fertilizer, but also help to prevent water pollution and improve the ecological environment. In this paper, the effects of biochar on leaching of nitrogen from two types of soils in China are studied by leaching experiments. Biochar made from corn stover was applied to the soil at a rate of 10 t / ha, 50 t / ha and 100 t / ha while simulating a field urea application of 240 kg.N / ha and simulating a precipitation equivalent to 10 mm per day Rinse the soil with deionized water. The analysis of the composition and content of nitrogen in the leachate showed that the leaching loss of total nitrogen in the calcareous soil and the purple soil accounted for 7.5% and 9.0% of the total nitrogen content in the soil (soil + urea), respectively, without the application of biochar, The leaching of nitrogen mainly occurred during the first 130 mm precipitation, and the leaching loss accounted for 96% of the total leaching loss. Of the leached components, in addition to nitrate nitrogen, organic nitrogen is also an important constituent, both of which account for 48% of the total nitrogen leached. Biochar application can significantly reduce the leaching of nitrogen. The biochar application rates of 50 t / ha and 100 t / ha decreased 29% and 74% of the leaching loss of Chernozem, respectively, and reduced the leaching losses of purple soil by 41% and 78% respectively. However, the application rate of biochar at 10 t / ha increased the leaching loss of black and calcareous soil by 22% and 2% respectively. This suggests that lower levels of biochar could promote leaching of nitrogen. Biochar inhibition of organic nitrogen leaching is greater than nitrate nitrogen. The biochar application rates of 100 t / ha decreased the leaching loss of organic nitrogen and nitrate nitrogen by about 88% and 62%, respectively, due to different soil types. The above results provide a theoretical basis for seeking technical methods for soil nitrogen leaching.