不同作物栽培模式下施用改良剂对重金属铅、镉的影响

Effects of soil amendment on heavy metals lead and cadmium under different crop cultivation patterns

【目的】研究水稻栽培和丝瓜栽培两种作物栽培模式下施用改良剂对土壤理化性质及重金属铅、镉的影响,为降低土壤重金属污染风险提供科学依据。【方法】在水稻栽培(R)和丝瓜栽培(V)两种作物栽培模式下,分别设不施改良剂(CK)、施用活性炭(AC)和石灰(L)等3个处理,共6个处理。通过单因素方差分析,研究不同作物栽培模式下改良剂因素对土壤理化性质及重金属铅、镉的全量和有效态含量及其在作物可食用部分中含量的影响。【结果】与水稻栽培模式相比,丝瓜栽培模式的土壤p H较高,有机质和重金属有效态含量较低;施用改良剂能促使土壤p H显著增加(P<0.05)。丝瓜栽培模式下,活性炭可降低土壤有效态铅和有效态镉的含量,石灰可降低土壤有效态铅含量。与镉相比,铅在水稻和丝瓜可食用部分中含量较低,改良剂对降低作物铅的效果不明显;活性炭增加水稻可食用部分镉含量,石灰降低水稻可食用部分的镉含量。【结论】选择适宜种植作物并兼施土壤改良剂可有效降低重金属铅和镉的污染风险。

[Objective ]Effects of soil amendment under paddy and luffa cultivation patterns on physical and chemical properties of soil and heavy metals lead（Pb） and cadmium（Cd） contents were studied, in order to provide scientific basis for reducing heavy metal risk. [Method]A field experiment was conducted with two different crop cultivation patterns viz., paddy cultivation pattern （R） and luffa cultivation pattern （V）, and different soil amendments viz., activated carbon and lime were applied, with no amendment application as control（CK）, the experiment included 6 treatments. Then, the effects of soil amendment under different cultivation patterns on soils were studied by one-way analysis of variance, including soil physicochemieal properties, soil total and available Pb and Cd contents, and Pb and Cd contents in edible portion of crops. [Result]The resuhs showed that, the soil pH under luffa cultivation pattern was higher than that under paddy cultivation, however, the soil organic matter and available heavy metals contents were lower. Both of soil amendments could significantly improve soil pH （P〈0.05）, however, under luffa cultivation pattern, the activated carbon reduced soil available Pb and Cd contents, while lime decreased soil available Pb content. Furthermore, in edible portion of paddy and luffa, the Pb content was higher than Pb content, and soil amendments were not effective to reduce Cd contents of crop. Activated carbon increased Cd content of edible portion of paddy, while lime reduced Cd content of edible portion of paddy. [Conclusion]Choosing suitable crop and soil amendment can reduce pollution risk of Pb and Cd.