四湖地区渍害稻田土壤有机质及其氧化稳定性

采用定点调查和大田采样的方法，较系统地研究了不同渍害程度的稻田土壤有机质和活性有机质与土壤主要农化指标之间的关系。结果表明：(1)活性有机质与土壤全氮、碱解氮和速效磷等肥力指标间的相关系数均达极显著水平，且比土壤有机质与其对应肥力指标间的相关系数均要大，比有机质更能反映出土壤有效养分的供应。(2)从通径分析结果看出：碱解氮对活性有机质的直接效应要小于速效磷对活性有机质的直接效应，前者为27.3％，后者为46．1％。渍害土壤中与活性有机质关系最密切的土壤肥力指标是速效磷和碱解氮。(3)初步认为用有机质氧化稳定性(Kos值)比用有机质含量或活性有机质含量能够更好地作为渍害土壤判断渍害程度的标准。

ORGANIC MATTER AND ITS OXIDABILITY IN WATERLOGGED SOIL IN FOUR-LAKE REGION, HUBEI PROVINCE

The relationship between organic matter(OM)and labile organic matter(LOM)with main fertility indexes from different waterlogged paddy soils was studied by fixed-point investigation and field sampling and soil analyses.The results are as follows:(1)The content of LOM is significantly correlated with the content of total nitrogen(TN),alkaline-hydrolysable nitrogen(AHN)and available phosphate(LP)of soil.As a result,the coefficients between LOM and TN,AHN and LP are greater than that of OM.LOM is a better index which reflects the supply of available nutrients in soil.(2)By means of path analysis the standardized regression coefficient between AHN and LOM is smaller than that between LP and LOM,which is27.3%and46.1%respectively.LOM has a closer correlation with LP than AHN.(3)It is concluded preliminarily that the oxidability of organic matter can be used as a better index in judging waterlogged degree of paddy soils than OM or LOM.