生物炭和堆肥产品施用对水稻体系中汞生物有效性的影响

Effect of biochar and compost product application on Hg bioavailability in rice system

我国是水稻生产和消费大国,但近年来在受汞(Hg)污染严重的区域中检测Hg的浓度严重超标,给粮食安全带来极大的威胁。生物炭和堆肥产品是良好的土壤改良剂,不仅可以增加土壤肥力,还可以固定重金属,减少对植物的毒害。通过水稻盆栽实验探究生物炭、堆肥产品以及二者协同作用下对土壤理化性质以及水稻体系中汞生物有效性的影响,结果显示:水稻植株中Hg浓度和土壤中生物有效性Hg含量呈显著正相关,和有机碳含量呈显著负相关。生物炭和堆肥产品的联合修复显著增加土壤的营养元素,土壤中生物有效性Hg的含量显著降低了61.8%,比单独施用生物炭和堆肥产品的效果更好。

The mobility and toxicity of mercury(Hg)are largely dependent on its chemical speciation,in which methylmercury is the most toxic compound and transformed by inorganic Hg in anaerobic conditions.Rice is one of the principal staple foods.High concentrations of Hg not only cause toxicity problems in plants,but also bring health risk to human.Both biochar and compost are soil amendments which can enhance soil fertility and plant growth.This study explored the effects of biochar,compost products,and their combined effects on soil physicochemical properties and the bioavailability of Hg in rice systems through pot experiments.The results showed that Hg concentration in rice plants was positively correlated with Hg bioavailability in soil,and negatively correlated with Hg content in soil.Hg concentration in rice plants was significantly positively correlated with the bioavailable Hg content in soil,and was significantly negatively correlated with soil organic carbon content.The combined remediation of biochar and composting product can significantly increase the nutrient elements in soil and reduce the bioavailability of Hg by 61.8%,which is better than the application of biochar and composting product alone.