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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.
Aiming at the phenomenon of soil acidification caused by paddy field re-planting in Taihu Lake, calcium carbonate and biochar were used as acidification modifiers to carry out indoor culture and multiple leaching simulation experiments. The effects of two amendments on soil acid- Ability and the effect of acidification restoration.The results showed that for every increase of 1 p H unit in the acidified vegetable soil soils, 3.92 × 10-2 mol · kg ~ (-1) CaCO3 was added into the soil based on the alkali buffer curve method, Or 27.73 g · kg -1 of biochar.Calcium carbonate increased the soil nitrogen mineralization rate significantly by 37% under the condition of no exogenous nitrogen, but had no significant effect on the content of ammonium and nitrate nitrogen in soil. Adding mineral soils significantly increased the rate of nitrogen mineralization by 35% -44%, and significantly increased soil nitrate nitrogen content by 42% -58%. Under simulated leaching, the biochar addition significantly reduced the volume of leachate by 24% The concentration of liquid nitrogen was 45%, and the amount of nitrogen leaching was significantly reduced by 42% -57%. However, the addition of calcium carbonate had no effect on the volume of leachate, increased the concentration of nitrogen in the leachate, and the amount of leached nitrogen increased by 12% -76% After rinsing, the soil p H value of different treatments decreased to some extent, and the soil p H value decreased with the addition of calcium carbonate without external nitrogen Low and exogenous nitrogen added biogas added to reduce the lowest rate.Therefore, calcium carbonate on the acidification of soil remediation efficiency, but under the conditions of added nitrogen to reduce soil nitrogen capacity, more suitable for acidification and need In the same time, biochar can effectively improve soil mineral nitrogen storage and nitrogen leaching while maintaining soil p H value, which is more suitable for the vegetable soil still under high-intensity cultivation.