钾肥强化植物间作修复镉锌污染土壤效应研究

小麦间作伴矿景天是一种原位绿色、边生产边修复重金属污染土壤的有效方式,施用钾肥是保障小麦增产的主要措施之一。为了研究不同类型和用量的钾肥对小麦间作伴矿景天修复镉(Cd)、锌(Zn)污染土壤的强化效果,采用室外盆栽试验方法,以不施钾肥为对照处理,研究了不同类型钾肥(氯化钾、硫酸钾)及施用量(50、100 mg·kg^-1和200 mg·kg^-1,以K2O计)对土壤pH和Cd、Zn含量、小麦和伴矿景天幼苗生物量及其Cd、Zn积累量的影响。结果表明:相较于对照处理,施用氯化钾和硫酸钾均能降低土壤pH,且施用量增至200 mg·kg^-1时土壤pH值降幅最大,分别降低了0.322和0.411。氯化钾和硫酸钾对土壤有效态Cd、Zn含量的提升效果均随施用量的提高而增强,均提高了小麦幼苗与伴矿景天生物量并促进了对Cd、Zn的积累。施用钾肥后,土壤Cd的去除率在15.1%~23.8%,土壤Zn的去除率在1.75%~4.70%。研究表明,施用钾肥均对小麦间作伴矿景天修复土壤Cd、Zn污染具有良好的强化效应,且氯化钾施用量200 mg·kg^-1的修复效果优于其他处理。

Intensification of the intercropping effect of phytoremediation of soil contaminated with cadmium and zinc using potassium fertilizer

Intercropping wheat(Triticum aestivum L.) and Sedum plumbizincicola is an effective method for in situ green production and remediation for phytoremediation of soil contaminated with heavy metals. The application of potassium fertilizer is one of the agronomic practices that increases wheat yield. In this study, a pot experiment was carried out to investigate the effects of potassium fertilizers on the amendment of cadmium(Cd) and zinc(Zn) contaminated soils using wheat and Sedum plumbizincicola intercrops. The effects of different application levels(50, 100 mg·kg^-1, and 200 mg·kg^-1, calculated in K₂O) of potassium chloride or potassium sulfate on soil pH, the concentration of Cd and Zn in the soil, and the biomass and Cd and Zn concentrations in wheat and Sedum plumbizincicola was evaluated. Corresponding treatments without the application of potassium fertilizers were used as the control. The results showed that increasing the application of potassium chloride or potassium sulfate decreased soil pH by 0.322 and 0.411 units, respectively. In addition, it increased soil available Cd and Zn concentration, plant biomass, and Cd and Zn concentration in wheat and Sedum plumbizincicola seedlings when compared with the control. Furthermore, the application of potassium fertilizer increased the removal rate of soil Cd and Zn from 15.1% to 23.8% and from 1.75% to 4.70%, respectively. This study shows that potassium fertilizer enhances soil amendment when wheat and Sedum plumbizincicola intercrops are grown in Cd and Zn contaminated soils. It can be concluded that the application of potassium chloride at 200 mg·kg^-1 achieves the best results.