水稻土发生分类的研究 Ⅱ.两种水型水稻土中有机质淋溶累积的特点及其与铁锰淋淀的关系

水耕条件促进了胡敏酸的累积和富虽酸的淋溶,使水稻土中耕层的H/F比值随发育度的提高而增大;有机质和腐殖质的含量与活性铁含量,铁水合系数及活化度呈显著或极显著的正相关,与晶胶率和晶化度呈显著或极显著的负相关。但是,与全锰.游离锰和活性锰含量的相关性未达到显著水准;耕层的H/F比值不宜作为水稻土亚类划分的指标,而只宜在土属等基层分类单元划分中应用。

STUDIES ON THE GENESIS AND CLASSIFICATION OF PADDY SOILS II.THE ELUVIATION AND ACCUMULATION OF ORGANIC MATTER AND ITS RELATION TO THE ELUVIATION AND ILLUVIATION OF IRON AND MANGANESE IN PERCOGENIC AND PERIODICALLY WATERLOGGED PADDY SOILS

The artificially waterlogged condition was favourable to the con- densation and accummulation of humic acid and the eluviation of fulvic acid so that the ratio of H/F in the plowed layer increased with the development of paddy soils.The contents of organic matter and humus had significantly positive correlations with the content of amorphous iron,the hydrated coef- ficient and activity of iron oxides,and significantly negative correlations with the ratio of crystalline iron/amorphous iron and the crystallinity of iron oxides,but no significant relation with the contents of total,amorphous and free manganese.The above results indicated that organic matter and humus did not favour the activation of iron oxides,but restricted their ageing in paddy soils,and did not affect the eluviation and illuviation of manganese significantly.The ratio of H/F in the plowed layer should not be used as an index for dividing the subgroup of paddy soils but as one of the indices for the family.