有机物料影响下土壤溶液中镉形态及其有效性研究

Study on the species in soil solutions and the availability of cadmium as affected by organic materials

研究了盆栽种稻条件下 ,有机物料对土壤水溶性镉、易解离态镉和可解离态镉的含量变化及其有效性的影响 .结果表明 ,不添加外源镉时 ,分蘖期猪粪和泥炭均降低了水溶性镉总量 .水溶性镉的 34% - 77%可被阳离子交换树脂解离 ,87%以上可被螯合树脂解离 .到成熟期水溶性镉的解离度升高 .水溶性镉总量与DOC和pH的变化趋势相反 .添加外源镉时 ,分蘖期猪粪和泥炭均降低水溶性镉总量 .成熟期水溶性镉总量与DOC的变化呈相反趋势 .在不添加外源镉的条件下 ,猪粪对水稻吸镉有促进作用 ,水稻吸镉量与溶液中镉含量不呈显著相关 .在添加外源镉条件下 ,猪粪和泥炭抑制分蘖期镉的吸收 ,根镉含量与溶液中镉的各形态均呈极显著正相关 .

The influence of two organic materials,pig manure and peat,on total water soluble Cd(WS\|Cd),easily labile Cd(El-Cd) and labile Cd(L-Cd) as well as their availability was studied under rice cultivation in pots.In the tillering stage,the concentration of WS-Cd was decreased strongly by pig manure but slightly by peat.The ratios of El\|Cd to WS\|Cd(B/A) and L\|Cd to WS\|Cd(C/A) were 0.34-0.77 and>0.87,respectively.The water soluble Cd was dissociated more easily by the two resins in mature stage than in tillering stage.The concentration of WS\|Cd among the treatments increased with the decrease of DOC and pH of the solutions in the two stages.The Cd uptake by the root was promoted by pig manure with no Cd added into the soils.When Cd was added,however,the absorption of Cd by the root was inhibited by the organic materials,and had significantly positive correlation with the three species of Cd in the tillering stage.