不同浓度螯合剂和浸提时间对土壤磷素提取效果研究

为确定螯合剂活化土壤磷素的最佳浓度和最优浸提时间,参考水肥一体化技术,在室内浸提条件下,研究了不同浓度(0,0.05,0.1,0.25,0.5,1.0g/L)乙二胺四乙酸(EDTA)和柠檬酸螯合剂(pH=4)在不同浸提时间(1,12,24,48,72h)下对粮田、菜田土壤和有效磷被钝化后菜田土壤中磷素提取效果。结果表明:EDTA和柠檬酸在粮田土壤上对磷素提取中最佳条件为螯合剂浓度0.05g/L,浸提时间12h。EDTA和柠檬酸在菜田土壤、明矾钝化和混合钝化(明矾∶白云石为1∶1)菜田土壤上提取磷素的最佳条件为螯合剂浓度0.5g/L,浸提时间12h;而在白云石钝化土壤中则为螯合剂浓度0.5g/L,浸提时间1h。总体来看,柠檬酸的活化提取磷素效果优于EDTA,尤其是在采用明矾和白云石钝化的土壤上。

Effect of Different Concentration and Extraction Time of Chelating Agents for the Soil Phosphorus Extraction in P-stabilized Soils

In this study, the extracting experiment was conducted to investigate the effect of EDTA and citric acid (pH=4) on P mobilizationin in the grain field soil, greenhouse soil and P-stabilized greenhouse soils under different concentrations (0, 0.05, 0.1, 0.25, 0.5, 1.0 g/L) and different extraction times (1, 12, 24, 48, 72 h), to make sure the optimal concentration and extraction time of chelating agent to extracts P from soils. The results indicated that the optimal concentration and extraction time were 0.05 g/L and 12 h for EDTA and citric acid in grain field soil. The optimal concentration and extraction time were 0.5 g/L and 12 h for EDTA and citric acid in green house soil, alum-stabilized soil and mixed-stabilized (alum:dolomite was 1:1) soil. The optimal concentration and extraction time were 0.5 g/L and 1 h for EDTA and citric acid in dolomite-stabilized soil. Generally, the effect of citric acid was better than that of EDTA, especially in alum and dolomite stabilized soil.