镉污染区水稻土磷素含量特征及其形态分布规律

Characteristics and speciation distribution of phosphorus in Cd contaminated paddy soil

以湖南省常德市Cd污染水稻土为供试土壤,研究了该区域土壤磷(P)元素含量状况、形态分布特征及其相关关系.结果表明,水稻土全磷含量范围为318.3—2016.2 mg·kg^(-1),总体上表现为适宜和丰富水平.然而,土壤有效磷的含量偏低,50%的土壤有效磷含量低于正常值(10 mg·kg^(-1)).在酸性水稻土中,无机磷含量依次为Al-P>Ca-P>O-P>Fe-P;而在碱性水稻土中,土壤无机磷含量为Al-P>Ca10-P>O-P>Ca2-P>Fe-P>Ca8-P.碱性水稻土有机磷占全磷比例高于酸性水稻土,达到30.1%—75.5%.土壤pH与Al-P、Ca-P之间存在极显著正相关关系(P<0.01),而与O-P之间具有显著负相关关系(P<0.05);土壤全磷与有机磷、Al-P之间存在极显著正相关性关系(P<0.01),而与有效磷、Ca-P具有显著正相关性关系(P<0.05);土壤有效磷与Al-P、有机磷含量之间分别表现为极显著和显著正相关关系.

The concentration,speciation distribution and its relationships of phospuorus in Cd contaminated paddy soils of Changde city,Hunan Province were investigated. The results showed that the concentration of phosphorus in the paddy soils ranged from 318. 3 to 2016. 2 mg·kg-1,reaching medium or abundance level of phosphorus in soil as a whole. However,the concentrations of available phosphorus in 50% of the soil samples were below 10 mg·kg-1. In acidic paddy soils,the content of inorganic phosphorus was in the decreasing order of Al-P〉 Ca-P〉 O-P 〉Fe-P,while the content of inorganic phosphorus in alkaline paddy soils was as follows： Al-P 〉Ca10-P 〉O-P〉 Ca2-P〉 Fe-P 〉Ca8-P. The ratio of organic phosphorus to total phosphorus in alkaline soils was 30. 1%—75.5% higher than that in the acidic soils. There was a significant positive correlation between pH and Al-P and Ca-P（P〈 0. 01）,and significant negative correlation with O-P（P 〈0. 05）. Anextremely significant correlation（P〈0.01） was observed between total phosphorus and the amount of organic phosphorus and Al-P,and total phosphorus was significantly correlated with available P and Ca-P. Available P was highly significantly（P 〈0.01） and significantly（P〈 0.05）,respectively,correlated with Al-P and organic phosphorus.