土壤水分对稻田土壤有效砷及碱性磷酸酶活性影响

采用室内模拟方法，在35%、65%和110%最大饱和持水量（WHC）条件下，系统地分析了稻田土壤有效砷及碱性磷酸酶活性变化规律.结果表明：砷污染稻田土壤后有效砷含量随砷污染浓度增加而增大，随培养时间延长逐渐降低，15d后趋于稳定；淹水降低了土壤有效砷含量及碱性磷酸酶活性；采用U=A/（1+B×C）模型较好拟合了不同水分下土壤碱性磷酸酶活性（U）与砷浓度（C）关系，表明碱性磷酸酶活性在一定程度上可表征不同水分下稻田土壤砷污染程度；计算得到稻田土壤砷轻度污染临界浓度（ED₁₀）为总砷67mg/kg和有效砷11mg/kg.研究表明适当调控土壤水分含量是控制稻田土壤砷毒性的有效方法之一.

Effects of soil moisture on available arsenic and alkaline phosphatase activity in paddy soil

The relationship of available arsenic and soil alkaline phosphatase activity at different soil moistures (35%, 65% and 110% of water holding capacity) was studied by an indoor simulated experiment. The results showed that available arsenic content increased after arsenic pollution and declined with aging until held steady after 15days. Flooding reduced the available arsenic content and soil alkaline phosphatase activity. The relationship of soil enzymatic activities (U) and arsenic concentration (C) was described well by the model U=A/(1+B×C), which indicated that soil alkaline phosphatase activity could be a good predictor for arsenic pollution in paddy soil under different soil moistures. Ecological dose 10% (ED₁₀) of total and available arsenic were 67mg/kg and 11mg/kg in paddy soil, respectively. The results of this study suggested that it was an efficient way to appropriately change the soil moisture to relieve the toxicity of arsenic contamination in paddy soil.