摘要
针对太湖地区稻田改种菜地后带来的土壤酸化现象,以碳酸钙与生物炭作为酸化改良剂,开展室内培养及多次淋洗模拟试验,比较两种改良剂对酸化菜地土壤持氮能力及酸化修复效果的影响.结果表明,基于碱缓冲曲线法,本试验用酸化菜地土壤每提高1个p H单位需向土壤中添加碳酸钙3.92×10-2mol·kg^(-1)或生物炭27.73 g·kg^(-1).无外源氮条件下碳酸钙添加使土壤氮矿化速率显著提高了37%,对土壤铵态氮、硝态氮含量影响不显著;生物炭添加使土壤氮矿化速率显著提高了35%~44%,且显著增加了土壤硝态氮含量42%~58%.模拟淋洗下,生物炭添加显著消减渗漏液体积24%,渗漏液氮浓度45%,显著减少氮淋失量42%~57%,而碳酸钙添加对渗漏液体积没有影响,增加了渗漏液中氮浓度,氮淋失量增加了12%~76%.淋洗后,各处理土壤p H值发生不同程度的降低,无外源氮条件下添加碳酸钙处理土壤p H值降幅最低,外源氮添加条件下生物炭添加处理降幅最低.由此可见,碳酸钙对酸化土壤修复效率较高,但在外源氮添加条件下降低了土壤持氮能力,更适用于酸化严重且需要休耕改良的菜地土壤;生物炭在维持土壤p H值的同时可以有效提高土壤矿质氮留存量,降低氮淋失,更适用于仍在高强度种植的菜地土壤.
In Taihu Lake region,more and more paddy fields are being converted to vegetable fields,which cause serious soil acidification and decreased soil nitrogen retention. In this study,calcium carbonate and biochar were used as acidification amendments to test their ability on soil acidification remediation and soil nitrogen retention improvement. Calcium carbonate and biochar addition rates were determined by p H buffering curves. An incubation experiment with and without nitrogen fertilization and multi-leaching simulation tests were conducted. The soil nitrogen mineralization rate,dynamics of the nitrogen content in soils and leachates,and soil p H were measured. The results showed that 3. 92 × 10^-2mol·kg^-1calcium carbonate and 27. 73 g·kg^-1biochar should be added into the tested acidified vegetable soil to recover the original p H value. Without nitrogen fertilization,the addition of calcium carbonate increased the soil nitrogen mineralization rate by 37% but had no significant effect on mineral nitrogen content. However,biochar addition significantly improved the soil nitrogen mineralization rate by 35%-44% and nitrate content by 42%-58%. Nitrogen leaching loss was cut down by 42%-57% in biochar addition treatment because of the lower leachate volume and nitrogen concentration,while calcium carbonate addition increased nitrogen leaching loss by 12%-76% because of the higher leachate nitrogen concentration. After leaching,the soil p H decreased for all the treatments. The soil p H change was the lowest for calcium carbonate addition treatment under no nitrogen fertilization and the lowest for biochar addition treatment under nitrogen fertilization. This result suggests that calcium carbonate is more applicable for seriously acidified soils which are fallowed and biochar is more suitable for the intensified vegetable fields because it can improve the soil nitrogen retention and soil p H,and reduce the nitrogen leaching loss.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2017年第9期3851-3859,共9页
Environmental Science
基金
国家自然科学基金青年科学基金项目(41501320)
国家重点研发计划项目(2016YFD0801101)
公益行业(农业)科研专项(201503106)
关键词
酸化菜地土壤
持氮能力
碳酸钙
生物炭
氮淋失
acidified vegetable soil
soil nitrogen retention
calcium carbonate
biochar
nitrogen leaching