中文摘要：

采用高锰酸钾和双氧水氧化法,研究比较重庆市6种不同类型土壤有机质的抗氧化稳定性。结果表明：（1）采用KMnO4氧化法评价土壤有机质化学稳定性应控制适宜的氧化剂浓度,KMnO4浓度〈0.1mol/L时,主要氧化土壤中的易氧化有机组分,浓度为0.3mol/L的KMnO4可较好地反映土壤有机质的抗氧化能力差异,6种土壤有机质抗氧化能力高低顺序为缙云山黄壤腐殖层〉紫色潮土〉嘉陵江沿岸冲积土〉灰棕潮土〉矿质黄泥〉灰棕紫泥紫色土。（2）土壤有机质的化学稳定性与pH、有机质含量、〈0.001mm粘粒含量以及全氮、速效氮、速效磷含量均存在明显的相关性,其相关特性在KMnO4高、低浓度时表现不同。（3）双氧水氧化法可较好地反映不同土壤密度分级土壤有机质的抗氧化稳定性,灰棕潮土、紫色潮土和矿质黄泥均随酸度增大而提高;灰棕潮土和紫色潮土轻组有机质（LFOM）抗氧化能力明显高于重组有机质（HFOM）;矿质黄泥和缙云山黄壤腐殖层LFOM和HFOM抗氧化能力无明显差异;研究发现农地土壤其有机质氧化率随酸度增加而连续提高,但林地土壤有机质氧化率变化幅度较小,均小于50%。

英文摘要：

Methods of potassium permanganate and hydrogen peroxide both were used respectively to analyze the anti-oxidation capability（AOC） of organic matters in different density fractions of soil particles, meanwhile to compare among six typical farmland soils in Chongqing and investigate the correlation with relevant soil basic characteristics. The results suggested that： （1）Methods of potassium permanganate for assessment of organic matter chemical stability should be in a certain range of concentrations, which oxidized apt-oxidized components in soils while KMnO4 concentrations was less than 0. 1 mol/L. Meanwhile, when KMnO4 concentration was 0. 3 mol/L, it could reflect the differences of anti-oxidization of organic matters among various soils. In addition, chemical stability of organic matters from six soils followed the order. Humus layer of yellow soil in Jinyun mountain〉 purple alluvial soil 〉 alluvial soil of Jialing riverside 〉 grey-brown alluvial soil mineral yellow mud 〉purple soil of grey-brown-purple mud. （2）Chemical stability of organic matters was found to have significant correlation with pH, content of organic matters, clay（〈0. 001 mm）, total nitrogen,available nitrogen and available phosphorus;method of hydrogen peroxide could be used to reflect better the AOC of organic matters in different density fractions of soils,which showed the capacities of grey-brown alluvial soil,purple alluvial soil and mineral yellow mud increased with acidity increasing,AOC of low fraction organic matter（LFOM） was higher than of heavy fraction organic matter（HFOM） in grey-brown alluvial soil and purple alluvial soil,however,the similar results were not observed between LFOM and HFOM in mineral yellow mud and humus layer of yellow soil in Jinyun mountain.In addition,oxidation rate of organic matter in farmland soil was found to have a consecutive increase with acidity increasing,however,the rate of organic matter from forest soil showed smaller changes,which was less than 50%.