施用生石灰对镉污染酸性土壤中水稻镉积累的影响

通过两年的田间小区试验,研究了生石灰基施和追施两种方式,以及375、750和1 125 kg/hm~2的施用量对镉污染酸性土壤中水稻生长和糙米镉含量的影响。结果表明:施用生石灰可使稻谷产量提高20~760 kg/hm~2;显著提高土壤pH值,最大提高幅度达到0.3个单位;并能有效降低糙米中镉的含量,且追施方式的降镉效果优于基施方式,其中追施1 125 kg/hm~2生石灰处理在两年试验中可使糙米镉含量均降低至国家食品卫生标准限值(0.2 mg/kg)以内。因此,在水稻孕穗末期追施1125 kg/hm~2可推荐为镉污染酸性稻田改良措施。

Effects of Lime Application on Cadmium Accumulation of Rice in Acidiccd-Confaminated Paddy Soils

To investigate the application methods and rates of lime on rice grain yield and content of Cd in brown rice, ifeld experiments were conducted in acidic Cd-contaminated paddy soils in 2013 and 2014. The lime was applied using basal application and dressing application at rates of 375, 750 and 1 125 kg/hm2. The results indicated that application of lime increased the rice grain yield by 20 to 760 kg/hm2. Soil pH was signiifcantly increase by lime application, reaching the largest value of 0.3. And the content of Cd in brown rice reduced by the application of lime. Moreover, the reduce effect was better in dressing application than in basal application. In two years, the content of Cd in brown rice in dressing application of lime at 1 125 kg/hm2 treatment was lower than National Food & Health Standard limit (0.2 mg/kg). In conclusion, the dressing application of lime at 1 125 kg/hm2 during last booting stage could be recommended for acidic Cd-contaminated paddy soil.