客土比例对土壤及油菜砷有效性的影响

Effects of soil dressing proportion on arsenic availability in soil and rape

为探究客土修复砷污染土壤的长期效果,在农业农村部岳阳农业环境野外科学观测实验站设计了客土与污染土壤不同混合比例的微区试验,研究了混合比例对土壤砷含量及油菜生长、吸收砷等的影响。结果表明:客土降低了污染土壤的砷含量,且土壤有效砷含量的降幅与客土比例显著相关,油菜各部位对砷的吸收量随客土比例的提高而降低。客土比例为40%时,油菜茎叶和籽粒的生物量最高,分别比污染土中增加了7.8%和12.8%,且根、茎叶和籽粒的砷含量分别比污染土中降低了67.4%、68.4%和82.2%。随客土比例的提高,土壤团聚体平均质量直径呈增加趋势,土壤pH和阳离子交换量则呈降低趋势。根据本研究结果,客土比例对土壤有效砷及pH、团聚体平均质量直径和阳离子交换量等理化指标具有显著影响,合适比例的客土能促进油菜生长并大幅度降低油菜的含砷量。

To explore the long-term effects of soil remediation on arsenic-contaminated soil,micro-area experiments were performed in the Scientific Observation and Experiment Station of Yueyang,Ministry of Agriculture and Rural Affairs.The effects of different mixing ratios of soil dressing and polluted soil on soil arsenic content,rape growth,and arsenic absorption were evaluated.The results showed that the content of available arsenic in polluted soil was reduced by soil dressing,and this decrease was positively correlated with the proportion of soil dressing:the arsenic absorption of rapeseed decreased with the increasing proportion of soil dressing.When the proportion of soil dressing was 40%,the biomass of stems,leaves,and seeds reached the maximum value,which increased by 7.8% and 12.8% compared with the polluted soil.In addition,the arsenic content of root,stem,leaf,and seed decreased by 67.4%,68.4%,and 82.2%,respectively,compared with the polluted soil.With the increased proportion of soil dressing,the mean weight diameter of soil aggregates increased,whereas the soil pH and cation exchange capacity decreased.The proportion of soil dressing had significant effects on soil available arsenic and physicochemical indexes such as pH,aggregate average weight diameter,cation exchange capacity,and other physical and chemical indexes,and the appropriate proportion of soil dressing promoted the growth of rape and greatly reduced its arsenic content.