石灰对生物炭和腐殖酸阻控水稻Cd吸收的效应

采用田间试验，研究了石灰-生物炭和石灰-腐殖酸两种联合修复剂及其不同施用量对酸性土壤中稻米Cd含量、产量和品质的影响，并对不同处理修复效果进行综合评估.结果表明，两种联合修复剂能显著降低稻米Cd含量17.39%~45.96%，降低土壤有效Cd含量18.29%~29.88%，.生物炭、腐殖酸施用量分别为5000，6000kg/hm²时，稻米Cd的降低效果最佳.石灰-生物炭处理中，降低稻米Cd含量的主要因子为土壤pH和土壤有效Cd含量（P<0.05），而石灰-腐殖酸处理则为土壤有机质含量与土壤有效Cd含量（P<0.05）.施加修复剂后稻米产量可达6637~7890kg/hm²，直链淀粉含量达到19.47%~27.26%；当腐殖酸施用量为7500kg/hm²时可使稻米产量提高10.97%，而石灰-生物炭处理对稻米产量无显著影响；采用层次分析法确定了稻米Cd含量、稻米产量、稻米品质和修复费用在修复效应评估中所占权重为0.608、0.150、0.102、0.140，综合评估结果显示土壤-水稻系统Cd阻控效应的联合修复技术为：在施用1200kg/hm²石灰的基础上同时施加6000kg/hm²腐殖酸.

Effect of lime on biochar and humic acid controlling cadmium uptake in rice

A field experiment was conducted to investigate the influence of different passivating agents (i.e., lime-biochar and lime-humic acid) and their dosages on the Cd content in rice, rice yield and the rice quality. And a comprehensive assessment was also carried out by considering the cost of each treatment. The results showed that the Cd content in rice and the available Cd in soil were significantly decreased by 17.39%~45.96% and 18.29%~29.88%, respectively, with the addition of two passivating agents into soil. When the addition amounts of biochar and humic acid were 5000 and 6000kg/hm², respectively, the effect of this passivating agent on reducing Cd concentrations in rice was optimum. In the treatment of lime-biochar remediation, the soil pH and soil available Cd content (P<0.05) were the main factors for reducing Cd content in rice, while in lime-humic acid remediation treatment, the soil organic matter content and soil available Cd content (P<0.05) were the main factors. Through soil remediation, the rice yield could reach 6637.49~7890.92kg/hm² and the amylose content was in the range of 19.47%~27.26%. When the dosage of humic acid was 7500kg/hm², the rice yield increased by 10.90%. However, the lime-biochar treatment had no significant effect on the rice yield. The analytic hierarchy process (AHP) results showed that the weighting coefficients of the four indicators including the Cd content, rice yield, rice quality and remediation cost in the comprehensive assessment were respectively 0.608, 0.150, 0.102 and 0.140. It was concluded that the optimal in-situ passivation treatment of Cd-contaminated paddy soil was to simultaneously apply 1200kg/hm² lime and 6000kg/hm² humic acid to the contaminated soil.