矿物源调理剂对南方酸性镉污染水稻农田的修复作用

Remediation of mineral conditioners on acid cadmium contaminated paddy farmland in southern China

为验证土壤调理剂在江西新余酸性镉(Cd)污染稻田上的应用效果,采用田间小区试验,研究了以牡蛎壳、石灰石等为原料的5种矿物源调理剂对土壤Cd、水稻产量及各部位中Cd含量的影响。结果表明:与对照相比,施用矿物源调理剂使土壤pH上升了1.17~1.69个单位,阳离子交换量增加了13.1%~41.2%;土壤有效态Cd含量降低了0.25%~18.8%;水稻根系、茎秆、叶片、谷壳和糙米中Cd含量分别显著降低了4.81%~48.0%、44.7%~84.9%、38.5%~76.9%、45.8%~79.2%和43.4%~75.5%,水稻产量增加了0.81%~17.9%。水稻不同部位中Cd富集系数表现为:根系>茎杆>叶片>糙米>谷壳,进入水稻体内的Cd主要富集在根系、茎杆和叶片部位。水稻各部位中Cd含量与土壤有效态Cd含量呈极显著正相关关系(P <0.01),而与土壤pH呈极显著负相关关系(P <0.01)。矿物源调理剂通过降低土壤Cd活性,可阻控Cd进入水稻迁移与富集,且能增加水稻产量。

A field plot experiment was conducted to assess the application effect of soil conditioners on acid cadmium(Cd)contaminated paddy field in Xinyu,Jiangxi Province.The effects of five mineral conditioners including oyster shell and limestone on soil Cd,Cd content in different organs of rice and yield were analyzed.The results showed that compared with the control,the application of mineral conditioners increased soil pH values by 1.17-1.69 units and cation exchange capacity by 13.1%-41.2%.Soil available Cd content was decreased 0.25%-18.8%,while the Cd contents in rice roots,stems,leaves,husks and brown rice were significantly reduced by 4.81%-48.0%,44.7%-84.9%,38.5%-76.9%,45.8%-79.2%and 43.4%-75.5%,respectively;and the rice yield was increased by 0.81%-17.9%.The concentration factor of Cd in different organs of rice was in the following order: root > stem > leaf > brown rice > husk. The Cd in rice was mainly enriched in root, stem and leaf. The Cd content in each organ of rice was significantly positively correlated with the soil available Cd(P < 0.01), but negatively correlated with soil pH (P < 0.01). The mineral conditioners exhibit better resistance and control effect on the migration and redistribution of Cd in the soil-rice system, which have yield-increasing effect and potential to ensure the safe production of rice.