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土壤氮素的淋失作用不仅造成土壤营养元素的损失,而且对河流和湖泊等环境水体的富营养化具有重要贡献。采用土柱室内模拟方法,通过模拟降雨淋滤,研究了生物炭对土壤淋溶液体积、pH和电导率以及NH4+-N和NO3-N淋溶的影响。试验中所用的生物炭是以桉树木屑为原料制成,分别按照炭土质量比1%、2%、4%、10%施用于土壤中。结果显示,与对照相比,向土壤添加10%、4%、2%、1%生物炭分别减少土壤水分损失14%、0.03%、0.02%和0.01%;随生物炭添加量增加,淋溶液的pH和电导率也逐渐增加;土壤生物炭添加量为10%、4%、2%时,NH4+-N淋溶量分别增加235%、28.1%、31.6%,NO3-N淋溶量分别增加4.2%、14.5%、25.6%;但生物炭添加量为1%的土柱NH4+-N淋溶量减少15.8%,NO3-N淋溶量减少19.2%。本研究表明,桉树生物炭对土壤氮淋溶与其施用量有关,1%施用量能减少氮淋溶,过量施用将增加氮淋溶,这种作用是否与生物炭种类有关有待进一步研究。
Leaching of soil nitrogen not only causes the loss of soil nutrient elements, but also contributes greatly to the eutrophication of environmental water bodies such as rivers and lakes. The effects of biochar on the leaching solution volume, pH and conductivity, leaching of NH4 + -N and NO3-N from soil were studied by simulating rainfall leaching with soil column simulation. The biochar used in the experiment was made from eucalyptus wood chips as raw materials, and was applied to the soil at mass percentages of 1%, 2%, 4% and 10%, respectively. The results showed that compared with the control, the soil moisture loss was reduced by 14%, 0.03%, 0.02% and 0.01% respectively by adding 10%, 4%, 2% and 1% biochar to the soil. PH and conductivity also increased gradually. When the amount of soil biochar was 10%, 4%, 2%, NH4 + -N leaching increased by 235%, 28.1%, 31.6%, NO3-N leaching increased 4.2%, 14.5% and 25.6%, respectively. However, the leaching amount of NH4 + -N in soil column with biochar added at 1% decreased by 15.8% and NO3-N leached by 19.2%. This study shows that eucalyptus biochar leaching is related to the amount of nitrogen applied to soil. The application rate of 1% can reduce the leaching of nitrogen, and the excessive application of nitrogen will increase the leaching of nitrogen. Whether this effect is related to biochar species remains to be further studied.