紫云英还田对土壤养分和重金属含量的影响

为提高六合稻麦轮作土壤质量,2018—2020年采用绿肥还田方式,设计开展紫云英-水稻轮作田间定位试验。设计紫云英-水稻轮作、小麦-水稻轮作2个耕作模式处理,研究紫云英还田对稻田耕层土壤养分含量、重金属的影响。结果表明,与小麦-水稻轮作相比,紫云英-水稻轮作可有效增加土壤养分,包括土壤全氮、有机质、速效钾、交换性钙、有效硫、有效锰、有效锌、有效钼;同时可改善土壤结构,土壤容重从1.32 g/cm³降低到1.21 g/cm³;还可减缓土壤酸化,土壤从pH 6.36升高到pH 6.51;可降低土壤重金属总铬、总铅、总砷、总汞的污染。综合考虑,紫云英还田可以有效减少冬季麦田肥料用量,并提高土壤质量,是六合水稻种植区较好的施肥模式。

Effects of Milk Vetch Returning to Field on the Content of Soil Nutrient and Heavy Metal

To improve the soil quality under rice-wheat rotation in Liuhe, a field experiment of milk vetch-rice rotation (2018 to 2020) was conducted to study the effects of milk vetch returning on the content of soil nutrient and heavy metal in paddy field. Two rotation patterns were designed: milk vetch-rice rotation and wheat-rice rotation. The results of this study showed that compared with wheat-rice rotation, milk vetch-rice rotation effectively increased soil nutrients, including total nitrogen, organic matter, available potassium, exchangeable calcium, available sulfur, available manganese, available zinc and available molybdenum, improved soil structure (soil bulk density decreased from 1.32 g/cm³ to 1.21 g/cm³), alleviated soil acidification (soil pH increased from pH 6.36 to pH 6.51), and reduced the soil pollution of total Cr, Pb, As, and Hg. In conclusion, milk vetch-rice rotation could effectively reduce the amount of fertilizer applied in winter wheat field and improve soil quality, which is a promising fertilization mode for Liuhe rice planting area.