碱性缓释肥对水稻吸收积累Cd的影响

Alkaline slow-release fertilizer decreased rice Cd uptake at Cd-contaminated paddy fields

选择长株潭地区典型化工点源污染、污水灌溉面源污染和大气沉降面源污染的镉(Cd)污染稻田,研究碱性缓释肥对稻田土壤有效Cd、水稻Cd含量的影响。结果表明:与常规施肥相比,北山、梅林桥、大同桥三个试验点施用碱性缓释肥的水稻产量增加290.8(+3.9%)~605.0(+7.3%)kg·hm^(-2),平均增产467.8 kg·hm^(-2)(+5.7%,P<0.05);三个试验点施用石灰和碱性缓释肥均能提高土壤p H,降低土壤有效Cd含量,其效果为碱性缓释肥小于石灰;三个试验点施用石灰和碱性缓释肥均能显著降低水稻稻米和茎叶Cd含量,在北山、大同桥酸性土壤中碱性缓释肥降低稻米Cd含量的效果优于石灰,两地的稻米Cd含量分别较施用石灰下降0.023mg·kg^(-1)(-13.5%)和0.080 mg·kg^(-1)(-26.7%),梅林桥偏中性的土壤上则为石灰降低稻米Cd含量的效果优于碱性缓释肥。

A field experiment was conducted to study the influences of alkaline slow-release fertilizer（AF）on soil available cadmium（Cd）and rice Cd content in typical Cd-contaminated paddy fields caused by chemical point source pollution（Beishan site）, sewage irrigation non-point source pollution（Meilinqiao site）and atmospheric deposition non-point source pollution（Datongqian site）in Chang-Zhu-Tan area. Three treatments were set up at each site, which were conventional fertilization（CK）, additional lime application at 1500 kg·hm^-2（CKCa）and application of alkaline slow-release fertilizer（AF）. The results showed that：The application of AF significantly increased rice yields by 290.8（＋3.9%）～605.0（＋7.3%）kg·hm^-2 in the three experimental sites（Beishan, Meilinqiao, and Datongqiao）with an average increase of 467.8 kg·hm^-2（＋5.7%,P〈0.05）compared with CK treatment; Applications of both lime and AF increased soil pH and reduced soil available Cd contents as compared to the CK treatment, with the effects of lime superior to AF at the three sites; Applications of both lime and AF decreased Cd contents in rice grain and stem at the three sites; AF was superior to lime on decreasing rice grain Cd con-tent at the acidic soil sites（Beishan and Datongqiao） with the rice grain Cd content further decreased by 0.023 mg·kg^-1（-13.5%）and0.080 mg·kg^-1（-26.7%）in the AF treatment as compared to CKCa treatment at the Beishan and Datongqiao sites respectively, while lime was superior to AF on decreasing rice grain Cd content at the nearly neutral site（Meilinqiao）.