水稻土对磷的吸持能力及环境风险研究

Characteristics of phosphorus sorption capacity and its environmental risk in paddy soils

以湖南Cd污染区水稻土为供试土壤,研究了土壤活性Al(Al_(ox))、活性Fe(Fe_(ox))、磷吸持指数(PSI)、吸持饱和度(DPSS)和释放风险指数(ERI)及其相关性关系.结果表明:供试水稻土中Al_(ox)和Fe_(ox)含量变异性较大,分别为55.67~1495.90 mg·kg^(-1)和1.50~13.63 g·kg^(-1),但有效磷含量变化幅度不大.水稻土吸持磷能力较弱,全部样品中PSI均低于30,但水稻土磷的吸持饱和度较低,85%的土壤样品DPSS低于磷淋失临界值(15%),且磷释放失风险(ERI)较小.水稻土中Al_(ox)含量和Fe_(ox)含量与PSI存在显著正相关关系(p<0.05),而与DPSS之间表现为显著负相关关系(p<0.01),DPSS和PSI呈现为显著负相关关系(p<0.01).

The parameters Al_（ox）,Fe_（ox）,phosphorus soil index（PSI）,degree of P sorption saturation（DPSS）,and environmental risk index（ERI）in Cd contaminated paddy soil samples of Hunan Province were investigated.The results show the contents of Al_（ox）and Fe_（ox）had a large variability,being 55.67~1495.90 mg·kg^-1and 1.50~13.63 g·kg^-1,respectively,but the available P had small variability.The sorption capacity of P by different paddy soil was low,and PSI values in all samples were below 30.Meanwhile,DPSS of paddy soils was low,and 85%of soil samples were below the threshold of P loss（15%）with low ERI of P.There was a remarkable positive correlation between Al_（ox）,Fe_（ox）and PSI（p0.05）,and extremely significant negative correlation with DPSS（p0.01）.DPSS was highly significant correlated with PSI（p0.01）.