云南省森林土壤腐殖质组成及特性研究

Composition and Characteristics of Humus in Forest Soils in Yunnan Province

以云南省10种森林土壤为研究对象,采用腐殖质分组测定法和分光光度计法,对土壤腐殖质组成及光学性质进行分析。结果表明:1)10种土壤可提取腐殖质碳量(HE)绝对含量变化大小依次为棕壤>暗棕壤>亚高山草甸土>暗棕色针叶林土>酸性紫色土>暗黄棕壤>红壤>赤红壤>黄壤>砖红壤;腐殖质各组分占比中胡敏素占总碳的比例最大;2)10种土壤腐殖化程度依次为:暗棕壤>亚高山草甸土>暗棕色针叶林土>酸性紫色土>赤红壤>棕壤>暗黄棕壤>红壤>黄壤>砖红壤,除暗棕壤、亚高山草甸土的PQ值大于0.5外,其他土壤均小于0.5,供试土壤腐质化程度总体偏低;3)不同土壤的总碳分别与腐质酸碳、胡敏酸碳、胡敏素碳、HA/FA、PQ呈线性正相关;4)不同土壤的色调系数均表现为FA>HA,富里酸分子结构比胡敏酸分子结构简单,E4/E6值总体变化幅度不大;5)10种土壤HA的芳化度、缩合度、化学稳定性相差不大。综上表明:供试土壤总体腐殖化程度较低,除暗棕壤、亚高山草甸土为胡敏酸型土壤外,其它皆为富里酸型土壤;土壤富里酸的芳化度、缩合度、化学稳定性对各种环境因子的响应能力较胡敏酸要高。

The composition and optical properties of humus in 10 different forest soils in Yunnan were analyzed by the method of humus grouping determination and spectrophotometer.The results showed that: 1) the content of HE changed in the order of brown soil > dark brown soil > subalpine meadow soil > dark brown coniferous forest soil > acid purple soil > dark yellow - brown soil > red soil > lateritic red soil > yellow soil > humid - thermo ferralitic,and the component of humin accounted for the largest proportion of total carbon;2) the order of humification degree in 10 soils was dark brown soil > subalpine meadow soil > dark brown coniferous forest soil > acid purple soil > lateritic red soil > brown soil > dark yellow - brown soil > red soil > yellow soil > humid - thermo ferralitic,and the PQ value of other soils was less than 0.5 except dark brown soil and subalpine meadow soil,indicating that the humification degree of the tested soils was generally low;3) the total carbon in different soils was positively correlated with HE - C,HA - C,HM - C,HA/FA and PQ,respectively;4)the tonal coefficients of different soils were FA > HA,the molecular structure of fulvic acid was simpler than that of humic acid,and the overall change of E 4/E 6 value was not significant;5)the aromaticity,condensation degree and chemical stability of HA in 10 soils were similar.In summary,the humification degree of the tested soils was relatively low,which were fulvic acid - type soils except dark brown soil and subalpine meadow soil which were humic acid - type soils.The condensation degree,aromaticity and chemical stability of soil fulvic acid was more responsive to various environmental factors than that of humic acid.