不同混灌模式对镉在冬小麦-夏玉米轮作系统中分配的影响

Effects of Blending Irrigation with Micro-polluted Water on Cadmium Distribution of Winter Wheat and Summer Maize Cropping Systems

为了探讨不同混灌模式对华北粮食主产区污灌农田重金属镉阻断效应,以典型污灌区多年来水质状况为背景,通过田间小区试验,研究了不同混灌模式下重金属镉在土壤-冬小麦、夏玉米轮作系统中的分配。结果表明,与微污染水灌溉相比,适宜的清污混灌处理显著降低了冬小麦籽粒中镉累积量,提高了冬小麦籽粒均匀度及产量,同时,适宜的清污混灌处理显著降低了夏玉米籽粒中镉累积量及穗轴质量,提高了夏玉米籽粒均匀度;确保粮食安全前提下,轻度污灌农田土壤10~20cm土层有效含镉量可作为夏玉米籽粒中含镉量的评价指标,估算有效镉临界值为0.36mg/kg。

According to water quality conditions of the typical sewage irrigation area for many years, field experiments were carried out to analyze cadmium distribution in the winter wheat and summer maize rota- tion system under blending irrigation schemes. The results indicated that under moderate blending irriga- tion scheme, cadmium accumulation in winter wheat grain decreased significantly, and winter wheat grain uniformity and yield were improved compared with micro-polluted water irrigation; furthermore, under moderate blending irrigation scheme, both cadmium accumulation in summer maize grain and cob weight decreased significantly, and summer maize grain uniformity increased. To ensure summer maize security, soil available cadmium content in 10~20 cm layer could be evaluation index of cadmium accumulation of summer maize grain in mild sewage irrigation farmland, and the calculated critical value of available cadmi- um was 0.36 mg/kg.