秸秆还田对土壤-水稻系统中Cd迁移富集影响研究进展

Effect of Returning Straw on Transfer and Accumulation of Cd in Soil-rice System: Research Progress

中国是水稻种植大国,每年有大量的秸秆资源可被资源化利用,其中直接还田是秸秆资源化利用的常见方式之一,也是减少秸秆焚烧的有效途径。但随着中国稻田土壤重金属镉(Cd)污染的日益加剧,秸秆受到Cd污染的程度也在增加,导致水稻秸秆富集大量的重金属Cd,所以,水稻秸秆直接还田将会把秸秆中富集的Cd再次带入土壤环境;然而,秸秆腐解过程中产生大量的活性有机物,而这些有机物对土壤中重金属Cd的活性存在较复杂的影响。如何评价水稻秸秆还田对土壤-水稻系统中Cd迁移富集的影响值得深入研究。笔者介绍了目前水稻秸秆Cd污染的状况,重点总结了还田过程中对土壤理化性质,如土壤有机质、pH值以及土壤有效态Cd含量的影响。但秸秆还田在增产的同时可能会增加水稻吸收积累Cd的风险,最后提出了秸秆还田应考虑的实际问题以及未来秸秆安全利用的展望,为今后秸秆安全、资源化利用提供可参考的理论指导。

China is a big agriculture country for rice planting, and produces large quantities of straw annually,which could be used in resource recycling. Returning into soil directly is a common approach of straw resourcerecycling and a way to reduce the straw-burning effectively. However, with the pollution of heavy metalcadmium（Cd） in paddy soil increasingly, the degree of straw contaminated by Cd is also increased, which leadsto the accumulation of Cd in rice straw, so returning straw to soil directly could bring Cd accumulated in ricestraw back to soil again. On the other hand, there are many active organic matters produced during the progressof decomposition of straw, which have complicated effects on the activity of Cd in soil-plant system. It deservesfurther study on the effect of straw returning on transfer and accumulation of Cd in soil-plant system. Theauthors introduced Cd pollution in rice straw at present, especially summarized the influences on soil physicaland chemical properties such as soil organic matter, pH value and the available content of Cd after strawreturning. Returning straw back to soil could increase yield and also the risk of Cd enrichment. Finally, thearticle pointed out some practical problems for considering, and discussed the prospect of safe utilization ofstraw.