南宁市郊不同类型土壤腐殖质垂直分布特征研究

Vertical distribution characteristics of different types of soil humus in Nanning suburb

[目的]分析南宁市郊不同类型土壤腐殖质垂直分布特征，以揭示土壤有机碳、腐殖质碳的分布特征及其与土壤含水量、pH的相关性。【方法】采用野外采样和室内分析相结合的方法，对南宁市郊菜园土、水稻土两类土壤剖面0-80cm有机碳含量及腐殖质组分进行相关分析。【结果】土壤腐殖质碳含量随土层深度增加呈递减趋势，菜园土有机碳含量由表层16．16g／kg递减为5．32g／kg，水稻土由表层最大值12．37g／kg递减到4．19g／kg；但菜园土有机碳含量总体上大于水稻土。两类土壤的胡敏酸、富里酸总碳量随土层深度增加呈下降趋势，菜园土中胡敏酸与富里酸比值总体上大于水稻土；两种类型土壤腐殖质全碳量均与富里酸呈极显著的正相关，与胡敏酸、胡敏素均呈正相关，与pH、含水量、HA／FA的值则呈负相关。【结论】南宁市郊两种不同类型土壤中有机碳含量均随土层深度递减，腐殖质全碳量与胡敏酸、富里酸、胡敏素呈正相关，与pH、土壤含水量、HA／FA呈负相关；菜园土腐殖化程度较高。

[Objective]Vertical distribution characteristics of different types of soil humus were analyzed to disclose the distribution characteristics of soil organic C, humus C and their correlations with soil moisture content and pH. [Method]Combining field sampling with laboratory analysis, correlation analysis was conducted on organic carbon content and humus components in 0-80 cm soil collected from paddy field and vegetable garden in Nanning suburb. [Result]Soil humus carbon content showed descending trend with the increase of soil depth. On the whole, organic carbon content of vegetable garden soil was higher than that of paddy soil. For vegetable garden soil, organic carbon content gradually de- creased from 16.16 （0-10 cm soil） to 5.32 g/kg （70-80 cm soil）; for paddy soil, organic carbon content gradually decreased from 12.37 （0-10 cm soil） to 4.19 g/kg （70-80 cm soil）. Total carbon content of humic acid （HA） and fulvic acid （FA） in the two types of soil both showed descending trend with the increase of soil depth. HA/FA value in vegetable garden soil was higher than that in paddy soil. For two types of soil, total carbon content in humus showed extremely significantly pos- itively correlated with fulvic acid, and significantly positively correlated with humic acid and humin, while extremely sig- nificantly and negatively correlated with pH, water content and HA/FA value. For vegetable garden soil, total carbon con- tent in humus was extremely significantly and positively correlated with fulvic acid and humin, while significantly and negatively correlated with pH, moisture content and HA/FA value. [ConclusionlHumification degree of vegetable garden soil was relatively higher. Total carbon contents in humus of the two types of soil in Nanning suburb were positively correlated with fulvic acid, humic acid and humin, while were negatively correlated with pH, water content and HA/FA value.