森林土壌の腐植形態について(第2報) : 土壌断面におけるUronic Acidの分布

Vertical distribution of the uronic carbon in the profiles of some forest soils in Shimane Prefecture was examined.
(1) In every soil type examined the content of the uronic carbon decreases from the surface to the lower horizon downwards.
(2) The rate of the uronic carbon to the total cardon shows a character of the profile of the individual soil type.
(3) In a brown forest soil and a black soil the rate increases from horizon to horizon downwards in the profile, and in the well drained profiles it increases more sharply than in the damp and poorly drained profiles.
(4) In a podsolised soil the rate gives a minimum value at the A_2 horizon and increases abruptly at the B horizon.
(5) The uronic carbon content in the surface soil was about 0.5-1.0% in every soil type.
It may be one of the interesting tendencies that the composition of the organic debris supplied and environmental conditions in which the organic matter decomposed seem to have little influence upon the uronic acid content in the surface horizons.