摘要
为探讨不同轮灌模式对华北粮食核心区污灌农田重金属镉阻断效应,通过典型污灌区田间试验,对土壤重金属镉在冬小麦-夏玉米轮作系统中的迁移、累积进行了研究。结果表明,苗期微污染水灌溉对籽粒中镉累积影响并不明显,返青拔节期、孕穗期微污染水灌溉可显著增加籽粒中镉累积及食品安全风险。同时,返青拔节期、孕穗期微污染水灌溉抑制了籽粒灌浆及籽粒均匀度,降低冬小麦产量,但对夏玉米产量影响并不明显。因此,苗期采用微污染水灌溉,返青拔节期和孕穗期采用清水灌溉可以有效阻断镉在籽粒中的累积;在确保夏玉米籽粒安全的前提下,中度污灌农田土壤10-20cm土层有效镉含量可以作为夏玉米籽粒中镉含量以及是否符合粮食卫生标准的评价指标,其评价模型近似为y=0.0853x-0.0036,估算有效镉临界值为1.21mg/kg。
For discussed the blocking effects of rotational irrigation with clean/micro-polluted water on cadmium distribution under wheat-maize rotation system,field experiments were carried on the typical sewage irrigation area for many years.Cadmium distribution was analyzed in the winter wheat and summer maize rotation system with rotational irrigation schemes.The results indicated that there was no obvious influences on cadmium accumulation in grains with micro-polluted water irrigation during seedling stage.However,there was significantly increased of cadmium accumulation in grains and aboveground purification rate with micro-polluted water irrigation during reviving-jointing stage and booting stage. Moreover,there was significantly inhibiting effects for grain filling and uniformity with micro-polluted water irrigation during reviving-jointing stage and booting stage,winter wheat grain yield was significantly decreased,but summer maize grain yield was slightly decreased.The cadmium accumulation was effectively blocked in grains with micro-polluted water irrigation during seedling stage and tap water irrigation during reviving-jointing stage and booting stage.To ensure summer maize security,soil available cadmium content in 10-20 cm soil layer could be evaluation index of cadmium accumulation of summer maize grain in mild sewage irrigation farmland,the evaluation model approximate for y=0.0853x-0.0036,the calculated critical value of available cadmium was 1.21mg/kg.
出处
《水土保持学报》
CSCD
北大核心
2015年第2期204-208,共5页
Journal of Soil and Water Conservation
基金
国家高技术研究发展计划项目(2012AA101404)
公益性行业(农业)科研专项(201203077)
关键词
镉
微污染水
清污轮灌
临界值
轮作系统
cadmium
micro-polluted water
rotational irrigation with clean/micro-polluted water
critical value
cropping system
