3种改良剂对不同土壤-水稻系统中Cd行为的影响

通过水稻盆栽试验,研究了钙镁磷肥、石灰和硅肥作为土壤改良剂对几种中度污染水稻土中Cd的赋存形态以及对水稻生长的影响和改善糙米品质安全性的作用。结果表明,由于各种改良剂的性质和改良机理上存在差异,改良效果各不相同,其中硅肥的改良效果最好,其次是钙镁磷肥,然后是石灰。虽然3种改良剂均能降低土壤中有效态Cd以及糙米和秸秆中Cd的含量,使稻米质量符合国家食品卫生安全标准,但土壤性质的不同会影响改良剂的效果。同一改良剂施用在红壤上的效果最为明显,其次是黄泥土,而呈碱性的潮黄土由于土壤有效态Cd的含量明显低于前两种土壤,施用改良剂后糙米和秸秆中的Cd含量虽有所降低,但改善效果不太明显。

Effects of Three Amendments on Behaviors of Cadmium in Different Soil-Rice System

Using pot experiments,the effects of different amendments,inciuding,calcium magnesium phosphate lime and silica fertilizer,in some types of paddy soils on rice growth,yield formation,uptake of Cd by brown rice and stalk,the content of effective Cd in soils and fractions of soil Cd were investigated.The results showed that the improvement effects varied with the different amendments due to their different characters and mechanisms.Among these amendments,silica fertilizer was the most efficient in suppressing Cd uptake by the plants,and the effect of calcium magnesium phosphate was better than that of lime.In addition,all three amendments could decrease the content of Cd in brown rice,stalk and effective Cd content in soil,and make rice accord with the National Food Safety Standards.However,different properties of soils influenced the improvement effects of amendments.The effects in paddy soil derived from red soil were the best,followed by yellow paddy soil.Content of effective Cd in alkali and fluro-aquic yellow paddy soil was lower than that in the other soils obviously.When three amendments were applied in alkali and fluro-aquic yellow paddy soil,content of Cd in brown rice and stalk was decreased,but the effects were not obvious.