Comparability of Electroultrafiltration and Ammonium Acetate-Lactate Extraction Data for Phosphorus and Potassium in Pseudogley Soils.

摘要

The aim of this research was to compare two standardized soil extraction methods [electroultrafiltration (EUF) and ammonium acetate-lactate (AL)] regarding potassium (K) and phosphorus (P) availability in pseudogley soils. In total, 60 pseudogley soil samples from 12 agricultural sites in eastern Croatia (each represented by five soil samples--replicates) were simultaneously analyzed by both methods. The relations of K and P with other important soil traits [pH, selective mineral clay content (SMC), humus content] were established by multiple regression analyses. Furthermore, a highly significant regression equation (P <= 0.01) was established for AL-phosphorus pentoxide (P2O5), using EUF-P-I and EUF-P-II separately as well as soil pH value determined in 1 M KCl as independent variables. The actual P amount extracted by AL differed by 9% from the value predicted by the regression function. According to the highly significant multiple regression function (P <= 0.01), AL-extractable dipotassium oxide (K2O) can be approximated using EUF-K (sum of EUF-K-I and EUF-K-II fraction), SMC, and the EUF-K-Q (ratio of EUF-K-II and EUF-K-I) as the independent variables. A deviation of calculated AL-K2O value from the extracted amount of K was 4%. These results point out the possibility of the comparison of EUF and AL extraction data in the evaluation of K and P availability in pseudogley soils. The necessity of more comprehensive research regarding the comparison of the EUF and AL method, taking into account plant nutrient acquisition specificity and a great number of interrelated soil and climate factors, was suggested.