不同施肥模式下的土壤-山药系统重金属含量特征

为探索不同施肥模式对“安顺山药”及其立地土壤重金属的影响特征，设计5个不同的施肥处理进行田间试验，以菌渣、植物源中药草等为原料，加入磷石膏、褐煤灰等矿物质，并利用活性氨基酸发酵法制成的菌渣发酵肥和活性氨基酸功能性药肥进行单施或化肥配施处理，对不同生长期土壤及植株中重金属的含量、生物富集特征和污染风险等级进行分析，并通过主成分分析评价不同施肥措施对山药及土壤重金属含量的影响程度。结果表明：（1）不同施肥处理均明显增加了块茎膨胀期土壤重金属含量，但到收获期Pb、Cu、Ni比种植前期有所下降，As、Cr显著增加；重金属综合污染程度为块茎膨胀期＞种植前＞收获期，Cd是主要污染物。（2）收获期山药块茎中Cd、Cu和Ni比膨大期明显下降，但As显著增加。（3）膨大期对重金属的富集能力高于收获期，但除未施肥对照（CK）和70%功能性药肥+30%复合肥处理（GYF）的块茎膨胀期山药Cr分别超标0.02和0.14倍外，其余处理在各时期均未超标；相比较于对照，不同施肥处理不同程度地降低了重金属在山药中的富集，其中菌渣发酵肥（JZ）处理和70%菌渣发酵肥+30%复合肥（JZF）处理最显著。综上，菌渣发酵肥与化肥配施对土壤重金属影响不大，功能性药肥和化肥配施对重金属影响较明显，单施功能性药肥和菌渣发酵肥能一定程度缓解土壤重金属污染和降低山药块茎中重金属的富集。

Characteristics of heavy metal content in soil-Yam system under different fertilization modes

In order to explore the effects of different fertilization modes on heavy metals content in Anshun yam and its site soil, five different fertilization treatments were designed to conduct field experiments, which were used discarded edible fungus stick or herb of plant source as the raw materials, with the addition of phosphogypsum, lignite ash and other minerals, and using the active amino acid fermentation method to make the fungus residue fermentation organic fertilizer and functional drug organic fertilizer of active amino acid, as either single- or dosed-fertilizer treatments. The contents, bioaccumulation characteristics and pollution risk levels of heavy metals in soil and plants at different growth stages were analyzed, and the degree of effect of different fertilization measures on heavy metals in yam and soil was evaluated by principal component analysis. The results showed that: (1) different fertilization treatments significantly increased the soil heavy metal content in the tuber expansion stage, but at harvest stage, Pb, Cu and Ni decreased compared with that in pre-planting stage, while As and Cr increased significantly; the comprehensive pollution degree of heavy metals was tuber expansion stage > pre-planting stage > harvest stage, and Cd was the main pollutant. (2) Cd, Cu and Ni of yam at harvest stage decreased significantly compared with that at pre-planting stage, but As increased significantly. (3) The enrichment capacity of heavy metals at the tuber expansion stage was higher than that at the harvest stage, but Cr of yam at