Interferences in the determination of isotopically exchangeable P in soils and a method to minimise them

被引:37
作者
Hamon, RE [1 ]
McLaughlin, MJ [1 ]
机构
[1] CSIRO Land & Water, Glen Osmond, SA 5064, Australia
来源
AUSTRALIAN JOURNAL OF SOIL RESEARCH | 2002年 / 40卷 / 08期
关键词
phosphate buffering capacity; molybdate-reactive P; colloids; silica; tropical soils;
D O I
10.1071/SR02045
中图分类号
S15 [土壤学];
学科分类号
0903 ; 090301 ;
摘要
In soils with a high phosphate buffering capacity or in soils with large amounts of colloidal P in soil solution, E-values often overestimate P availability. These problems have been ascribed to a variety of causes including analytical difficulties in terms of measuring low concentrations of P, colorimetric interferences, and inadvertent measurement of non-isotopically exchangeable colloidal P. We investigated measurement of E-values in 8 soil types, of which 6 had properties likely to give overestimates of size of the available pool of P based on results of previous authors. The potential for overestimation of the E-value due to interferences described above was identified in several soil types. A simple anion exchange resin purification step was introduced to the E-value methodology. The resin adsorbs both P-31 and P-32 isotopes in proportion to their concentration in the solution and minimises transfer of colloids and Si into the analysed eluant, thereby providing a simple way to increase the eluant P concentration and to avoid analytical interferences.
引用
收藏
页码:1383 / 1397
页数:15
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