广西红锥成熟林土壤的理化特征

Soil physical and chemical characteristics of Castanopsis hystrix mature forests in Guangxi

【目的】探究广西不同区域红锥成熟林土壤理化特性,综合评价红锥成熟林不同区域土壤质量,为红锥的可持续发展提供理论依据。【方法】以广西10个区域红锥成熟林为研究对象,对其土壤理化特性进行调查,运用主成分分析法综合评价其土壤质量。【结果】1)不同区域对土壤物理性质影响差异显著。土壤容重、最大持水量、毛管持水量、毛管孔隙度均受到土层深度显著影响,随着土层加深,土壤容重递增,最大持水量、毛管持水量、毛管孔隙度大部分表现为递减,自然含水率、非毛管孔隙度、总孔隙度没有规律性。区域和土层深度的交互作用对土壤容重、最大持水量、毛管持水量、非毛管孔隙度、总孔隙度有显著影响。不同区域红锥成熟林土壤物理性质处于中等变异程度;2)不同区域对红锥成熟林土壤化学指标影响差异极显著。土壤有机质、全氮、速效钾、有效氮、速效磷均受到土层深度显著影响,随着土层加深,土壤有机质、全氮、速效磷、速效钾大部分的区域递减,全钾、全磷、速效氮、pH值变化规律不一。土壤pH值变异程度较弱,有效氮变异程度较强烈,其他土壤养分变异程度中等。除了土壤全氮外,其他养分均处于缺乏状态;3)各区域红锥成熟林土壤质量综合评价结果表明,土壤质量处于中等水平占比50%,处于良水平占比20%,处于差水平占比30%。【结论】总体来说,各区域红锥成熟林土壤的透水性、通气性和持水能力比较协调;土壤均呈酸性,土壤养分处于中等变异程度;土壤质量指数由桂东向桂南递增,红锥成熟林土壤质量整体处于中等水平。广西区域种植红锥能很好地稳定土壤质量和土壤肥力。

【Objective】Investigation of soil physical and chemical characteristics of Castanopsis hystrix mature forests in different regions of Guangxi was studied to evaluate comprehensively the forests soil quality,and may provide insights for sustainable management of C.Hystrix forests.【Method】Mature C.hystrix forests in 10 regions of Guangxi were selected as research materials,the soil characteristics were analyzed,and soil quality was evaluated by principal component analysis.【Result】1)Soil physical properties were significantly different among regions.Soil depth significantly affected soil bulk density,maximum water holding capacity,capillary water holding capacity and capillary porosity.The bulk density increased along with the deepening of the soil layer,while the other 3 indexes mostly decreased,natural water content,non-capillary porosity and total porosity varied irregularly.Interaction effect of region and soil depth significantly influenced soil bulk density,maximum water holding capacity,capillary water holding capacity,non-capillary porosity,and total porosity.Coefficient variation(CV)analysis of soil physical properties showed that the variation was moderate;2)Regions had extremely significant effects on soil chemical indexes.Soil depth significantly affected the contents of soil organic matter,total nitrogen,available potassium,available nitrogen and available phosphorus.As soil depth increased,the soil organic matter,total nitrogen,available phosphorus and available potassium decreased in most regions.The total potassium,total phosphorus,available nitrogen and pH values changed irregularly.CV of soil pH value was weak,CV of available nitrogen was strong,and CVs of other soil nutrients were moderate.Except for soil TN,all the other nutrients were in a state of deficiency;3)Comprehensive evaluation of soil quality of the forests showed that 50%of the tested sites had soil evaluated at medium level,20%at good level,and 30%at poor level.【Conclusion】In general,soil of mature C.hystrix forests in the regions had relatively appropriate permeability,aeration and water holding capacity.The soil was acidic and the soil nutrients varied moderately.The soil quality index increased from eastern Guangxi to southern Guangxi,and the soil quality of C.hystrix mature forest was mostly at a medium level.Soil quality and soil fertility could be maintained by planting C.hystrix in Guangxi.