Effects of Different Organic Materials on Contents and Morphologic Changes of Mn in Black Soil

Three kinds of organic materials were used for culture experiment, namely livestock manures, natural organic materials and half decomposed organic materials. And the modified BCR sequential extraction procedure was used to analyze the morphologic changes of Mn. The study was focus on the effects of different kinds of organic materials on contents and morphologic changes of Mn in black soil. And the results show that different kinds of organic materials all increase the total Mn contents in soil. The amplifications of livestock manures and natural organic materials are higher then half decomposed organic materials. Comparing with fertilizers only, all kinds of organic materials increase the contents of each Mn fraction. For Weak acid soluble (Aci.) fraction of Mn, natural organic materials increase most, for Reducible (Red.) fraction, livestock manures increase most, for Oxidizable (Oxi.) fraction, all kinds of organic materials are nearly the same, and for Residual (Res.) fraction, livestock manures increase most. In addition, different kinds of organic materials also lead to morphologic transformation of Mn, comparing with fertilizers only, livestock manures lead to inert transformation, while natural organic materials lead to active transformation, and half decomposed organic materials lead to inert transformation.