黑土中有效态镍提取方法的选择

Methods for Extracting Available Nickel in Black Soil

供试7种提取剂的最佳提取条件是:提取温度均为(25±1)℃;提取时间为DTPA 2 h,醋酸铵30 min,其余5种提取试剂60 min;提取时的土液比为蒸馏水和DTPA 1∶2,醋酸铵1∶10,其余4种提取试剂1∶5。DTPA作为提取剂时,盆栽作物的吸镍量与有效镍提取量之间的相关性达到极显著水平,并好于其它试剂。DTPA和EDTA作为提取剂时,有效镍提取量与植株干物重之间均达极显著的负相关,且相关系数高于其他试剂。考虑到用DTPA作提取剂时,可以同时测定铜、锌、铁、锰多种金属元素,因此黑土中有效态镍的最佳提取试剂是DTPA,最佳提取条件为:温度(25±1)℃、土液比1∶2、180次min-1往复振荡提取2 h。

The best extraction conditions of seven experimental extractants were as follows. The temperature was 25℃± 1 ℃. The extraction time was 2 h for DTPA, 30min for NH4OAC, 60 min for others. The ratio of soil to solution was 1： 2 for distilled water and DTPA, 1：10 for NH4OAC, 1：5 for others. The correlation between the content of Ni in potted plant and the available Ni extracted by solution was extremely significant in the treatment of DTPA which was better than others. There was extremely significant negative correlation between extracted Ni and the dry weight of plant for DTPA, EDTA and the correlated coefficients were higher than others. With consideration of DTPA＇s capacity of measuring the contents of Cu, Zn, Fe, Mn and other metallic elements simultaneously, the best extractant to extract available Ni in black soil was DTPA. And its optimal extracting conditions were as follow. The temperature was 25 ℃ ± 1℃, the ratio of soil to solution was 1：2, and extraction time was 2 hours under 180 times/min oscillation.