生物炭对黄壤中氮淋溶影响:室内土柱模拟

Effects of biochar on soil nitrogen leaching:A laboratory simulation test with yellow soil column

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。

Soil nitrogen leaching not only causes soil nitrogen loss, but also has great contribution to the water body eutrophication. By the method of laboratory simulation test, this paper studied the effects of applying biochar on the leachate volume, pH, electrical conductivity （ EC）, and ammonium nitrogen （NH4^-N） and nitrate nitrogen （NO3--N） concentrations in a batch of yellow soil columns under simulated raining condition. The biochar was made from eucalyptus chips, and its application rates were 1%, 2%, 4%, and 10% of soil mass. Comparing with the control, applying 10%, 4%, 2%, and 1% biochar decreased the leachate volume by 14%, 0. 03%, 0.02%, and 0.01%, respectively. With the increasing amount of applied biochar, the leachate pH and EC increased. Under the application of 10%, 4%, and 2% biochar, the leachate NH4＋-N and NO3--N concentrations increased by 235%, 28. 1% and 31.6%, and 4. 2%, 14.5% and 25.6%, respectively, while under the application of 1% biochar, the leachate NH4＋-N and NO3--N concentrations decreased by 15.8% and 19.2%, respectively. This study showed that the effects of applying eucalyptus chips on the nitrogen leaching of yellow soil depended on the applied amount of the biochar. The addition of 1% biochar reduced the nitrogen leaching, while excessive biochar increased the nitrogen leaching. Whether the species of biochar materials may affect soil nitrogen leaching would be an issue to be investigated in the future.