耕作措施对设施菜田土壤中Hg的形态转化及升华效应研究

本文进行了不同技术措施对设施菜田土壤中Hg形态转化的影响研究,得到如下结果:(1)不同微生物菌剂对设施土壤中Hg形态转化具有不同的效应,AB菌能够促进土壤中结合态Hg向有效态的转化,处理45 d后,处理剂量在50 mL/kg土时,可增加有效态Hg达到49.88%;木霉菌和Eco-cleanM菌处理则促进了有效态Hg的固定化,其效应分别为4.40%～12.96%、11.63%～58.14%;(2)不同季节的设施菜田土壤进行汞形态转化和升华时具有显著差异,其中以7月中旬处理效果最好,可使土壤总汞含量的27.5%转化成气体并从土壤中逸出;(3)在具有密闭条件的塑料棚内,经过旋耕的土壤,汞的转化并形成气体的效应随时间增强,在8 d后变化趋于稳定;(4)利用多重覆盖可进一步提升设施菜田土壤中汞的转化和逸出数量,同时对土壤添加2.0 g/kg土的30%木醋能起到增效作用,可使土壤中汞总含量38.5%的汞从土壤中转向棚内空间。

Study on the form transformation and sublimation effect of Hg in greenhouse soil by farming measures

The effects of different technical measures on the transformation of Hg in greenhouse soil were studied,and the following results were obtained:(1) Different microbial agents had various effects on morphological transformation of Hg in greenhouse soil.AB bacterial agents could promote the conversion of combined Hg to the effective state in the soil,which could increase to 49.88%,after treatment for 45 days,with the dosage of 500 mL/10 kg soil.On the contrary,Trichoderma and Eco-cleanM promoted the immobilization of available Hg,with effects of 4.40% to 12.96% and 11.63% to 58.14%,respectively.(2) There existed significant differences in the transformation and sublimation of mercury in the greenhouse soil in different seasons.The effect was best when treated in mid-July,which could convert 27.5% of the total mercury content of the soil into gas and escape from the soil.(3) The effect of mercury conversion to gas state increased with time after the farming of the soil,and it became stable after 8 days,in the closed plastic shed.(4) Multiple coverage could further increase the conversion and escape of mercury in the greenhouse soil.Adding 2.0g/kg soil of 30% wood vinegar could facilitated conversion effect,with 38.5% of total mercury content transferring to the shed space from soil.