石灰与生物炭对矿山废水污染农田土壤的改良效应

为研究石灰、生物炭单施和配施对酸性矿山废水污染农田土壤理化性质及作物生长的影响，在云南某酸性矿山废水污染农田，开展石灰（0、1 500、4 500 kg·hm^-2）、生物炭（0、15 000、45 000 kg·hm^-2）单施与配施的大田试验。结果表明：双因素分析表明，石灰和生物炭对土壤pH、速效养分含量、有效态Cd含量、养分含量、产量存在显著的影响，并且二者之间存在显著的交互作用。与不添加石灰和生物炭处理相比，石灰单施升高酸性磷酸酶活性，增加细菌和放线菌数量，降低脲酶活性和碱解N含量；生物炭单施增加真菌和放线菌数量，减少碱解N含量，降低酸性磷酸酶和脲酶活性；石灰、生物炭配施增加微生物数量和碱解N含量，升高脲酶活性，降低酸性磷酸酶活性；石灰、生物炭单施和配施均显著提高土壤pH和速效K含量，增加CEC，显著降低土壤速效P、有效态Cd和玉米植株Cd含量，同时增加玉米生物量、养分含量和产量。相关分析表明，土壤pH值与有效态Cd含量呈极显著负相关；玉米产量与土壤有效态Cd含量呈显著负相关。研究表明，石灰、生物炭单施和配施均能改善酸性矿山废水污染农田土壤理化性质，降低土壤Cd有效性和玉米Cd含量，提高玉米产量，具有明显的土壤改良效应。石灰与生物炭配合施用更佳，其中4 500 kg·hm^-2石灰+45 000 kg·hm^-2生物炭处理效果最好。

Beneficial effects of lime and biochar application on farmland soil polluted by mine wastewater

This study examines the effects of single application and combined application of lime and biochar on the physical and chemical properties of farmland soil polluted by acid mine wastewater and crop growth. Moreover, the study provides technical support for the improvement of farmland soil polluted by acid mine wastewater. A field experiment of single and combined application of lime(0, 1 500, 4 500 kg·hm^-2) and biochar(0, 15 000, 45 000 kg·hm^-2) was carried out in a farmland polluted by acid mine wastewater in Yunnan Province. Two factor analysis showed that lime and biochar had significant effects on soil pH, available nutrient content, available Cd content, nutrient content, and yield, and there was significant association between them. Compared with the control, lime application alone increased acid phosphatase activity, the number of bacteria and actinomycetes and decreased urease activity and the content of alkali hydrolyzed N. Single application of biochar increased the number of fungi and actinomycetes but decreased the content of alkali hydrolyzed N and the activities of acid phosphatase and urease. The combined application of lime and biochar increased the number of microorganisms and alkali hydrolyzed N content and urease activity, but decreased acid phosphatase activity. Single and combined application of lime and biochar significantly increased soil pH and available K content, cation exchange capacity, maize biomass, nutrient content, and yield, but it significantly reduced soil available P, available Cd and Cd content of maize plants. Correlation analysis showed a highly significant negative correlation between soil pH and available Cd content. There was a significant negative correlation between maize yield and soil available Cd content. Both single and combined application of lime and biochar can improve the physical and chemical properties of farmland soil polluted by acid mine wastewater, reduce the availability of soil Cd and the content of maize Cd, and increase the yield of maize, which has an obvious effect on soil improvement. The combined application of lime and biochar is the most effective among other applications. Further, the optimal treatment effect is the observed with 4 500 kg·hm^-2 lime+45 000 kg·hm^-2 biochar.