Cu Zn Cd和EDTA对土壤酶活性影响的研究

Effects of Cu, Zn, Cd and EDTA on Soil Enzyme Activities

土壤酶是反映土壤肥力的一个敏感的生物指标,还可在一定程度上反映土壤环境的优劣状况,在盆栽条件下研究了Cu、Zn、Cd单一污染土壤的脲酶、碱性磷酸酶和蔗糖酶的活性,结果表明,3种酶活性在根际土壤中的分布均大于在非根际中的分布,且Cu、Zn、Cd单一污染土壤中3种酶活性均小于对照无污染土壤。从土壤酶活性的角度来看,化学改良剂EDTA对锌污染和轻度铜污染土壤有较好的改良作用,而对镉污染和重度铜污染修复效果不显著。土壤脲酶、碱性磷酸酶和蔗糖酶活性可作为土壤污染程度的生物指标。

Enzymatic activities in heavy metal polluted soil had been widely used to indicate the extent of pollution.In a pot experiment, the effects of Cd, Zn, and Cu on soil enzyme activities in rhizosphere and non-rhizosphere soils, and the effect of EDTA, as a soll amendment, on the heavy metal contaminated soils were studied, the activities of urease, alk-phosphatase, and inverstase activities in soils contaminanted by Cu, Zn, and Cd were measured. Wheat was used as the study crop and planted in the plastic pot. Root bags made of 300 mu nylon cloth were used to divide rhizosphere and non-rhizosphere soils. The results showed that soil enzyme activities were higher in the rhizosphere than that in the non-rhizosphere soil. In addition, compared with the untreated control, the contamination of Cu, Zn and Cd reduced soil enzyme activities, both in the rhizosphere and in the non-rhizosphere soil. After adding EDTA to these soils, the only inhibition of soil enzyme activities by Zn was significantly alleviated （P〈0.05）. In conclusion, we can use soil urease,alk-phosphotase and invertase activities as indexes to indicate the degree of soil contamination by Cu, Zn and Cd.