再生回用水灌溉对作物品质及土壤质量的影响

考查了不同水质（三级处理水、二级处理水、污水、清水作对照）灌溉对农作物（黄瓜、白菜和玉米）品质和土壤质量的影响,同时测定了灌溉后农作物的可食用部分中的氯离子、磷酸盐、硝酸盐、亚硝酸盐以及残留的重金属含量.结果表明,三级水和二级水浇灌对作物品质无显著影响,污水浇灌可使部分营养成分含量升高,如以蛋白质为例,4种水浇灌时3种作物中蛋白质含量范围分别为：黄瓜0.736?2～0.812?5 mg/kg;白菜0.134?8～0.164?5 mg/kg;玉米10.28～10.84 mg/kg.污水浇灌会产生较高的硝酸盐积累,其中污水浇灌的白菜中硝酸盐含量高达554.4　mg/kg,已达到污染水平.三级水和二级水灌溉对作物中重金属含量影响不大,而污水浇灌会使作物中重金属发生明显的积累,因此污水不适于作灌溉水源.短期灌溉内土壤的钠吸附比(SAR)在3.5～4.5之间,表明土壤未发生明显碱化,重金属也未发生显著积累.

Effect of Reclaimed Water Used for Irrigation on the Quality of Crops and Soil

The effect of different water (tertiary effluent, secondaryeffluent, raw sewage as well as tap water as control) used for irrigation on the qualities of crops (cucumber, cabbage and corn) and soil was investigated; meanwhile, the contents of residual chlorine ion, phosphate, nitrate and nitrite as well as residual heavy metals present in crops were studied respectively. The results demonstrated that the secondary effluent and tertiary effluent had no significant effect on the crop quality. In contrast, irrigation with raw sewage could lead to increase of partial nutrient components in the crops. If protein contents were taken as an example, the proteins for three crops corresponding to different water sources were in the range of 0.7362~0.8125mg/kg for cucumber, 0.1348~0.1645mg/kg for cabbage and 10.28~10.84mg/kg for corn, respectively. Irrigation with sewage produced more accumulation of nitrates (554.4mg/kg for cabbage). Considerable effects of irrigation with secondary effluent and tertiary effluent were not observed; however, sewage was not suitable for irrigation due to an apparent accumulation of heavy metals in crops. During short-period irrigation, sodium adsorption ratio (SAR) values of soil ranged from 3.5 to 4.5, suggesting that there was no concern on soil basification. As well, obvious accumulation of heavy metals in soils was not detectable.