平衡时间及含水量对红壤有效态铅提取量的影响

Effect of Equilibrium Time and Water Content on Pb Availabilityin Red Soils

比较了4种浸提剂在9种平衡时间和2种土壤含水量条件下对红壤铅的提取能力。结果表明,随着平衡时间延长和土壤含水量增加,铅提取量有逐渐增加的趋势。不同提取剂提取的有效态铅达到平衡的时间分别为HAc4小时;NH4NO32小时;HCl2小时;EDTA1.5小时。不同提取剂的提取能力不同,对于黄筋泥,其顺序为:1molL-1NH4NO3<2.5%HAc<0.05molL-1HCl<0.01molL-1EDTA;对于红砂土,其顺序为:2.5%HAc<1molL-1NH4NO3<0.05molL-1HCl<0.01molL-1EDTA。

Four extractants,including 0.05mol L^(-1)HCl,1mol L^(-1) NH_4NO_3(pH5.0),0.05mol L^(-1)EDTA(pH7.0) and 2.5%HAc,were used to evaluate the availability of Pb in two variable charge soils at nine equilibrium time and two water content.The contents of Pb extracted increased with the equilibrium time and water content.The equilibrium time was 4 hours for HAc,2 hours for NH_4NO_3 and HCl,1.5 hours for EDTA.The extract ability increased with the order of 1mol L^(-1) NH_4NO_3,2.5%HAc,0.05mol L^(-1) HCl,0.01mol L^(-1) EDTA for the REQ soil and 2.5%HAc,1mol L^(-1) NH_4NO_3,0.05mol L^(-1) HCl,0.01mol L^(-1) EDTA for the RAR soil.