湘赣边界山区林地土壤养分分异规律

目的]对湘赣边界山区林地在不同海拔高度及植被类型影响下的土壤养分特征和空间分异规律进行研究,为林地土壤的合理利用及培肥提供依据。方法]采集林地表层土壤,测得各养分指标含量,运用修正的内梅罗综合指数法和变异系数法,对该区土壤综合肥力和空间变异性进行评价。结果](1)试验区土壤整体呈酸性,有机质和全氮养分含量较高,但普遍缺乏速效养分(磷、钾)。(2)随着从丘陵、低山到中山海拔等级的升高,土壤有机质、全氮、速效磷含量及综合肥力系数不断增加;pH值、有机质、全氮的空间变异性不断减小。(3)不同林地生态系统覆被下土壤综合肥力表现为:灌木林>针阔混交林>毛竹林>阔叶林>针叶林;空间变异性规律为:灌木林>针叶林>毛竹林>阔叶林>针阔混交林。(4)人工林的土壤有机质、全氮、速效钾、pH值及土壤综合肥力都低于天然林。结论]中山海拔等级林地、针阔混交林、天然林对维持良好的土壤养分状况具有更大潜力。

Spatial Variation of Forest Soil Nutrient in Hu'nan-Jiangxi Boundary Mountain Areas

Objective] To improve the studies on ecological conditions, utilization, and protection of forest resources, the soil spatial variation and the spatial distribution of sample sites in forest of Hu'nan-Jiangxi boundary mountain areas were analyzed.Methods] The soil nutrient content was measured, and the comprehensive advantage of soil nutrients was evaluated by the changed Nemero formula, the soil spatial variability was evaluated by the coefficient of variation(CV).Results] (1) Soils of the experimental region were characterized as acidic and had high values of soil organic matter(SOM) and soil total nitrogen(STN) generally, but were all lack of soil available phosphorus(SAP) and soil available potassium(SAK)nutrients, (2) With the rise of elevation level of hill, low mountain, middle mountain, the values of soil pH, SOM, STN, SAP and comprehensive fertility coefficient increased, but the spatial variation of soil pH, SOM and STN decreased. (3) According to the different forest types, the comprehensive advantage of soil nutrients were made as follow:shrubs> the mixed forest> Phyllostarchys pubescens forest> broad-leaved forest> coniferous forest, the order of the spatial variation were:shrubs> coniferous forest> P. pubescens forest> broad-leaved forest> the mixed forest. (4) All the soil nutrient indicators of natural forest, except the SAP, were higher than that of plantation.Conclusion] The forest in middle mountain, mixed forest and natural forest have more potential to maintain good soil nutrient status in the study area.