钝化材料对农田土壤Cd形态及微生物群落的影响

为探讨钝化剂对土壤Cd生态风险和土壤微生物群落结构的影响，通过田间试验，在轻度Cd污染水稻田中施加钝化剂（海泡石、石灰、秸秆生物炭和螯合铁肥）开展相关研究。结果表明：施加钝化剂使土壤pH值提高0.17~1.29个单位，Cd的可交换态减少29.79%~64.48%。施加海泡石、石灰、秸秆生物炭使得微生物群落的多样性指数（ACE、Chao1、Shannon）增加，但螯合铁肥不利于微生物群落的生长，多样性指数均减少。土壤微生物群落随钝化剂的施加发生显著改变，变形菌门、厚壁菌门、拟杆菌门相对丰度有所增加，芽单胞菌门、绿弯菌门、螺旋体菌门相对丰度均降低。相关性分析表明，pH和Cd是影响微生物群落的关键因素，此外Cd形态也对微生物群落产生了影响。研究表明，施用钝化剂可降低土壤中重金属Cd的潜在生态风险，改变土壤微生物群落结构，使多种微生物群落得到抑制或增强。

Soil cadmium content and microbial community structure are affected by passivator application

To investigate the effects of passivators on soil cadmium content and soil microbial community structure, field experiments were conducted in which passivators(sepiolite, lime, straw biochar, and chelate iron fertilizer)were applied to lightly Cd-contaminated rice fields. The results showed that passivator application increased soil pH by 0.17~1.29 units and decreased the extractable state of Cd by 29.79%~64.48%. The application of sepiolite, lime, and straw biochar increased microbial community diversity(ACE, Chao1, Shannon); however, chelated iron fertilizer application was not conducive to microbial community growth and led to decreased microbial diversity. The relative abundances of Proteobacteria, Firmicutes, and Bacteroidetes increased when passivators were applied, while the relative abundances of Gemmatimonadetes, Chloroflexi, and Saccharibacteria decreased. Correlation analysis showed that pH and Cd were the key factors affecting the microbial community; additionally, Cd morphology had an impact on the microbial community. Studies have shown that the application of a passivating agent can reduce the potential ecological risks posed by Cd in soils, change the structure of the soil microbial community, and inhibit or enhance the growth of many microbial communities.