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作 者 ：刘利军 洪坚平 闫双堆 党晋华

期 刊 ：植物营养与肥料学报 2013年 19卷 1期 页码：138-145

关键词：腐植酸；pH；砷形态；生物毒性；

Keywords:humic acid, pH, arsenic form, biotoxicity,

摘 要 ：为了探索在不同pH条件下腐植酸对土壤中砷形态转化及生物毒性的影响，应用油菜盆栽试验，检测砷加入土壤后15 d、45 d、90 d土壤中AEAs（水溶态、可交换态和碳酸盐结合态）Fe,MnAs（铁／锰氧化物结合态）, O, SAs（有机物及硫化物结合态）, ResAs（残渣态）的含量及油菜生物量。结果表明，外源水溶态砷加入土壤后均迅速向相对稳定的形态转化, 15 d时A3H1（pH 9.5，腐殖酸用量为0 g/kg）和A3H4（pH 9.5，腐殖酸用量20 g/kg）处理的AEAs含量分别为13.40 mg/kg、9.23 mg/kg，转化率分别为78.7%、82.51%; 在90 d时， A3H4处理的AEAs、 Fe, MnAs含量分别为6.28 mg/kg、1.23 mg/kg，仅为处理A3H1处理的53.9%和10.7%， O,S As、ResAs含量分别为20.24 mg/kg、41.21 mg/kg，是处理A3H1的165%和127%。说明腐植酸更有利于土壤中AEAs向其他相对稳定的形态转化，主要体现在O,SAs的增加，腐植酸对碱性土壤中砷向较稳定形态转化的促进作用更加显著，而且与腐植酸的施用量呈正相关。外源砷在碱性条件下对植物的毒害更大，腐植酸用量在10 g/kg土时就可以有效降低砷的毒害。

Abstract: Rape cultivated in pot was used to investigate the effects of humic acid on the form transformation and biotoxicity of As in soils. The contents of AEAs, Fe, MnAs, O, SAs and ResAs in soils and the rape biomass were measured on the 15th, 45th and 90th day. The result shows that the exogenous hydrosoluble As is rapidly transformed to a relatively stable form in soils. After 15 days, the AEAs contents of A3H1（pH 9.5，humic acid rate is 0 g/kg） and A3H4（pH 9.5，humic acid rate is 20 g/kg ) are 13.40 and 9.23 mg/kg respectively, the conversion rates reach up to 78.7% and 82.51%. On the 90th day, the contents of AEAs and Fe, MnAs of A3H4 are 6.28 and  1.23 mg/kg,  respectively. Which account for only 53.9% and 10.7% of A3H1 The contents of O, SAs and ResAs are 20.24 and 41.21 mg/kg, which are 165% and 127% of A3H1 These results suggest that humic acid facilitates the AEAs transform into other stable forms, and the most obvious change is the increase of O, SAs. Humic acid demonstrates a more significant promotive effect when the soil is alkaline, which is positively correlated with the humic acid consumption. The exogenous As has a stronger toxicity to plants in alkaline conditions. The dosage of humic acid at 10 g/kg soil is effective to decrease the As toxicity.

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