双孢蘑菇菌渣还田下水稻土Cu、Cd、Pb、Zn相关性分析及污染评价

Correlation analysis and pollution assessment about Cu, Cd, Pb and Zn in paddy soil under Agaricus bisporus residues recycling

为探究菌渣直接还田是否会给农田土壤带来潜在的重金属污染,在稻麦轮作条件下采用定位随机区组设计,共7个处理,包括CK(对照,不施肥)、T1(化肥提供100%纯N)、T2(菌渣提供100%纯N)、T3(菌渣提供120%纯N)、T4(菌渣提供140%纯N)、T5(菌渣提供100%P_2O_5)和T6(菌渣提供100%K_2O),研究各处理下水稻土0～20 cm土层Cu、Cd、Pb和Zn含量变化情况,应用污染负荷指数法和潜在生态风险评价法对该层土壤进行污染评价,运用Pearson相关分析和聚类分析探究菌渣还田下水稻土重金属来源与菌渣的关系。结果表明,稻麦轮作后,水稻土重金属含量随菌渣施入量的增多而增大。污染评价结果说明,T1和T4处理给水稻土带来的重金属污染威胁及生态风险较严重,而T5处理带来的污染威胁和生态风险较轻微。经相关性分析得到,菌渣可能成为Cu、Pb和Zn来源。稻麦轮作时利用菌渣替代磷肥配施适量化肥可降低菌渣和化肥较高的重金属风险,有利于农业生产土壤资源的可持续利用。

To explore the mushroom residue contained some heavy metals can bring potential heavy metal contamination to farmland soil,the experiment including CK(blank control,no fertilizer),T1(100%N from fertilizer),T2(100%N from Agaricus bisporus residue),T3(120%from Agaricus bisporus residue),T4(140%N from Agaricus bisporus residue),T5(100%P2O5 from Agaricus bisporus residue)and T6(100%K2O from Agaricus bisporus residue)was carried out with random experimental plots in rice-wheat rotation.During the trial,Cu,Cd,Pb and Zn contents in surface soil(0~20 cm)under each treatment was analyzed to realize the variance condition before and after rice-wheat rotation.Then,the pollution assessment of Cu,Cd,Pb and Zn in this soil layer under each treatment was made by using pollution load index and potential ecological risk index.Moreover,the relationship between mushroom residue and the source of heavy metal was explored in paddy soil under mushroom residue returning through Pearson′s correlation analysis and cluster analysis.The results indicated that Cu,Cd,Pb and Zn contents in the paddy soil were raised gradually with the increase of mushroom residue after rice-wheat rotation.T1 and T4 treatments could owe higher pollution and ecological risk to paddy soil,but T5 treatment made lower.The correlation analysis revealed that mushroom residue could bring some Cu,Pb and Zn into paddy soil.Finally,for the sustainable use of soil resources in agricultural production,the combined application of mushroom residue and the right amount of fertilizers instead of P fertilizer could cause much slighter heavy metal risk than mushroom and fertilizer in rice-wheat rotation.