水分管理与秸秆还田对作物吸收土壤中砷的影响

Effects of Water Management and Straw Returning on Arsenic Uptaken by Crops from Contaminated Soil

为了解农田水分管理方式与秸秆还田对砷污染农田中生长农作物吸收砷的影响,在某一砷污染农田的水稻-油菜连作系统中设置稻季淹水灌溉与湿润灌溉和稻季秸秆还田与油菜季秸秆还田双因素试验,分析不同水分管理和秸秆还田对水稻和油菜各器官中砷积累的影响。结果表明,油菜籽粒中砷含量明显低于水稻谷物;稻季湿润灌溉水稻籽粒及茎叶中砷含量低于淹水灌溉,前者为后者的47.59%~48.30%和6.43%~13.36%;稻季水分管理方式对后续作物油菜籽粒砷积累影响不明显。水稻秸秆在油菜田还田处理的水稻籽粒中砷含量低于油菜秸秆在水田还田处理的水稻籽粒,但秸秆还田时间对油菜籽粒中砷含量影响不明显。分析表明,湿润灌溉土壤水溶性As(Ⅲ)和As(Ⅴ)总量及As(Ⅲ)/As(Ⅴ)的比例都显著低于淹水灌溉。研究认为,湿润灌溉和水稻秸秆油菜季还田可降低农产品中砷的积累。

In order to understand the effect of water management and straw returning on the absorption of arsenic bycrops from arsenic contaminated farmland soil,a pot experiment was conducted in a rice-rape continuous croppingsystem to study the effects of two kinds of water managements（flooding irrigation and wet irrigation）and two ways ofstraw returning（rice straw returning and rape straw returning）on arsenic（As）accumulation in the different organsof two plants.The results showed that the arsenic content in rape seeds was significant lower than that in rice grain.The contents of arsenic in grains,stems and leaves of rice with wet irrigation were lower than those with flooded irri-gation,the former were 47.59%~48.30% and 6.43%~13.36%,respectively,of the latter.Water management modesin rice growth season had no significant effect on the accumulation of arsenic in the following rape season.The con-tent of arsenic in rice grain for rice straw returning to rape field was lower than that for rape straw returning to ricefield. However,the effect of straw returning time on the content of arsenic in rape seeds was not obvious.Total concen-trations of water soluble soil As^（3＋）and As^（5＋）and the As^（3＋）/As^（5＋）ratio for wet irrigation was significant lower than thosefor rice straw returning.The results suggested that both wet irrigation and rice straw returning could control the accu-mulation of arsenic in agricultural products.