Abstract
In studying the fulvic acid fraction of paddy soil, the existence of so-called β-fraction (WAKSMAN'S) comes into question. In the paddy soil at the several experimental stations, the writer could see the decrease of β-fraction with the increasing amount of dressing farmyardmanure. It seems that its decrease depends upon the Al_2O_3 in fulvic acid which is decreased by the increase of farmyardmanure. When the fulvic acid is fractionized into four fractions by FORSYTH'S absorption technique, almost all Al_2O_3 and Fe_2O_3 are in Fraction A, isolated from organic matter, and in other fractions no β-fraction is formed. It seems that β-fraction is the organic matter co-precipitated when the Aluminium precipitated, and its amount depends on the Aluminium amount in the fulvic acid fraction.
