Effects of extraction and fractionation period on the yield of a tropical peat soil (Hemists) humic acids

Abstract

The isolation of humic acids from soils is laborious and time consuming. Factors that affect the yield of humic acids isolated from soils include extraction, fractionation and purification periods. This study was conducted to investigate whether a relationship could be separately established between extraction time, fractionation time, and the yield of humic acids of a tropical peat soil (Hemists), as well as the relationship between both variables on the yield of humic acids of this soil. Modified standard procedures using 0.1 M KOH were used to isolate humic acids from a tropical peat soil. Even though there was a quadratic relationship between extraction period and yield of humic acids, there was no relationship between fractionation period and yield of humic acids. There was negative correlation between the yields of extraction and fractionation periods. This finding enables the isolation of humic acids of Hemists in less than 10 h instead of the existing average period of 48 h, therefore helping in facilitating the idea of producing for instance ammonium-humate or K-humate (N and K foliar organic fertilizers) from peat soils. © 2007 Science Publications.