水稻土发生分类的研究 Ⅰ、铁的淋溶淀积与水稻土的发育

水稻土离铁作用明显,并以耕层最为强烈.耕层中的晶质铁和非游离铁被活化、淋溶,使耕层的全铁、游离铁、晶质铁及非游离铁量均随发育度的提高而渐减.耕层下淋的活性铁在心土层氧化淀积,导致心土层的全铁.游离铁和晶质铁量随发育度的提高而渐增.氧化铁的晶胶率和晶化度在剖面中有显著的分异,其变化趋势可确切地反映出不同水型下的成土特点。

STUDIES ON THE GENESIS AND CLASSIFICATION OF PADDY SOIL Ⅱ.eluviation and illuviation of iron during the development of paddy soil

Ferrolysis in the paddy soil is distinct,and most active in the plowed layer.Crystalline iron and non-free iron in the plowed layer are activated and transformed into amorphous iron,and then eluviate downward so that the contents of total iron,free iron,crystalline iron and non-free iron of the plowed layer decrease gradually with development of the paddy soil.Amor- phous iron eluviated from the plowed layer is oxidized and illnviates in the subsoil,it causes the contents of total iron,free iron and crystalline iron of the subsoil to increase with the development of the paddy soil.The ra- tio of crystalline iron/amorphous iron (C.i./A.i.) and crystallinity of iron oxide segregate clearly in the profile of paddy soil,their changing tendency could reflect exactly the characteristics of pedogenic process of the paddy soil under various water regimes.