Effects of heavy application of fresh cow dung on to the humus composition of an Ando soil, southern Kyushu [Japan]
1993
Shinagawa, A. (Kagoshima Univ. (Japan). Faculty of Agriculture) | Miyauchi, N. | Udagawa, Y.
The study to elucidate the effects of heavy application of cow dungs to an Ando soil (T-C: 8.46%, C/N: 23.5, Base saturation degree: 8.99%) in southern Kyushu on the characteristics of their soil humus composition was made. Obtained results and attempt assumptions are as follows: 1) For the original soil, chemical fertilizer applied soils and for cow dungs, any colored substances were unextracted with 0.1M-Na4P2O7 after repeated extraction of humus with NaOH (pH: 12.5), obtaining the colorless extract, whereas, after being treated with the same NaOH treatment, some amount of highly humificated humus soluble in 0.1M-Na4P2O7 was extracted from the soils with heavy application of cow dungs. Amount of the above-mentioned 0.1M-Na4P2O7 soluble humus was increased and humification degree of their humic acid became higher with the increase of amounts of applied dungs. 2) With the increasing of amounts of applied dungs, amounts of DCB, pyrophosphate soluble R2O3, especially amounts of Al2O3, were made to be decreasing, but oxalate soluble Al2O3 was increased. Therefore, amounts of calculated free Al2O3 were increased with the increasing of applied dungs, accompanied by the higher values of base saturation degree, lower values of iso-electric-point, phosphate absorption coefficient of the dungs applied soils. And basing on these confirmation, it is assumed that some amounts of highly humificated Al(Fe)-humates in the original soils were converted to Ca(Mg)-humates by mutual interaction of soils and dungs, resulting undissolution with NaOH and dissolution with Na4P2O7, and these Ca(Mg)-humates were reverted to Al(Fe)-humates during croppings are succeeding on dungs applied soils without fertilizer manure
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