再生水灌溉方式对重金属在土壤中残留累积的影响

Soil heavy metal residue under different treated waste-water irrigation technique and management

不同灌溉技术（沟灌、地下滴灌）和灌水方式（充分灌溉、分根交替灌溉）下再生水灌溉对重金属在土壤中残留影响的田间试验表明：其他条件相同时，收获后充分灌水小区土壤重金属Cd含量高于分根交替灌水小区；再生水（二级处理污水）地下滴灌小区高于二级处理污水加氯地下滴灌小区；二级处理污水沟灌小区高于清水灌溉小区；充分灌溉下二级处理污水滴灌小区低于沟灌小区，而分根交替灌溉下沟灌低于滴灌。土壤Pb含量的变化规律与Cd基本相似，除滴灌下二级处理污水区低于二级处理污水加氯小区，无论充分灌溉还是分根交替灌溉均为滴灌低于沟灌。不同处理收获后土壤Pb含量均有不同程度降低；而二级处理污水灌溉小区土壤cd含量较试验前增加0．62％～7．78％，其他处理均有不同程度减小。试验结果为再生水资源的农业安全利用提供了技术依据。

Different irrigation techniques （furrow irrigation and subsurface drip irrigation） and management （full irrigation and partial rootzone drying irrigation） were used to study heavy metal residue in soils irrigated with treated waste-water. The results show that Cd content in soils after harvest with full irrigation is higher than in that with partial rootzone drying irrigation under the same irrigation technique and water quality. Cd content in soils under subsurface drip irrigation with treated waste-water is higher than in those with treated waste-water and a few additional chloride; that under furrow irrigation with treated waste-water is higher than in soils with fresh water irrigation. Cd content in soils under full irrigation with treated waste-water and subsurface drip irrigation is lower than those with furrow irrigation. However, Cd content in soils with partial rootzone drying irrigation and subsurface drip irrigation is higher than in soils with furrow irrigation. Pb content exhibits the same trend as Cd for almost all the treatments, except that Pb content in soils under subsurface drip irrigation with treated waste-water is lower than that with treated waste-water and a few additional chloride ; also those for soils under subsurface drip irrigation with treated waste-water are lower than for furrow irrigation under both partial rootzone drying irrigation and full irrigation. Soil Pb residue decreases under different treatments after harvest, while soil Cd residue under treated waste-water irrigation increases by 0.62%～7.78% after harvest （though it decreases under other treatments）. The study provides a solid scientific guide for treated waste-water irrigation.