不同植被类型紫色土腐殖质的剖面分布特征

目的]研究龙川江流域6种不同植被类型对紫色土腐殖质(胡敏酸、富里酸、胡敏素)和土壤养分(总磷、速效磷、总氮、碱解氮)剖面分布特征的影响,为该地区保持土壤肥力提供科学依据。方法]采用锯齿形布点法,采集紫色土表层至30 cm深度的3个土层紫色土样品,用3次4分法分离多余样品,并测定相应指标。结果]总磷、速效磷、总氮、碱解氮的含量和腐殖质、胡敏素、胡敏酸、富里酸碳量随土壤深度的增加而减小,枯枝落叶层显著高于其他层(地下0—10,10—20,20—30 cm),不同植被类型土壤无显著差异。果园土壤腐殖质及其组成显著高于桉树林覆盖土壤,表现为果园落叶阔叶林暖温性针叶林针阔混交林灌丛桉树林。土壤腐殖质各组分之间均存在极显著正相关关系,腐殖质组成与土壤有机质、总磷、速效磷、总氮、碱解氮均存在显著正相关关系。结论]果园和落叶阔叶林下土壤腐殖质及其组分显著高于其他植被类型土壤,腐殖质组分含量与土壤理化性质之间呈极显著正相关。

Distribution Characteristics of Humus in Purple Soil Profile Under Different Vegetation Types

Objective] The profile distribution of purple soil humus:humic acid (HA), fulvic acid (FA), and humin (HM), and soil nutrients:total phosphorus (TP), available phosphorus (AP), total nitrogen (TN), and available nitrogen (AN), under six different vegetation types in Longchuanjiang River basin were studied to provide a scientific basis for the maintenance of soil fertility.Methods] Soil samples were collected from different soil horizons (0-10, 10-20, and 20-30 cm) at each sampling point using the zigzag method. Then, soil samples of each layer were evenly mixed and the removal of redundant samples was performed by quartering three times and the corresponding indicators were determined.Results] The content of TP, AP, TN, AN, humus carbon, HM carbon, HA carbon, and FA carbon decreased with soil depth under the six vegetation types. The litter layer content was significantly higher than that of the other layers (0-10, 10-20, and 20-30 cm). There was no significant difference in soils among the different vegetation types. The humus and its composition in the orchard soil were significantly higher than that in the Eucalyptus forest, which was characterized by orchard > deciduous broad-leaved forest > warm temperate coniferous forest > coniferous and broad-leaved mixed forest > shrub > Eucalyptus forest. Correlation analysis showed that the humus components had very significant positive correlations with soil organic matter, TP, AP, TN, and AN.Conclusion] Soil humus and its components in orchards and deciduous broad-leaved forests are significantly higher than those in other vegetation types, and there is a significant positive correlation between humus and soil physical and chemical properties.