Spatial Patterns of Soil Organic Matter,Nitrogen,Phosphorus and Potassium in a Subtropical Forest and Its Implication for Forest Management

亚热带森林土壤氮磷钾和有机质的空间格局及其对森林经营的启示

Total nitrogen(TN),total phosphorus(TP),total potassium(TK),and soil organic matter(OM)can significantly affect forest growth.However,these soil properties are spatially heterogeneously distributed,complicating the prescription of forest management strategies.Thus,it is imperative to obtain an in-depth understanding of the spatial distribution of soil properties.In this study,soils were sampled at 181 locations in the Tropical Forest Research Center in the southwestern Guangxi Zhuang Autonomous Region in southern China.We investigated the spatial variability of soil OM,TN,TP,and TK using geostatistical analysis.The nugget to sill ratio indicated a strong spatial dependence of soil TN and a moderate spatial dependence of soil OM,TP,and TK,suggesting that TN was primarily controlled by intrinsic factors(e.g.,soil texture,parent material,vegetation type,and topography),whereas soil OM,TP,and TK were controlled by intrinsic and extrinsic factors(e.g.,cultivation practices,fertilization,and planting systems).Based on the spatial variability determined by the geostatistical analysis,we performed ordinary kriging to create thematic maps of soil TN,TP,TK,and OM.Model validation indicated that the thematic maps were reliable to inform forest management.

土壤氮磷钾和土壤有机质明显影响森林生长。但是,这些土壤特性具有空间异质性,这使得进行可持续森林经营变得更加复杂。因此,必须深入了解土壤氮磷钾和有机质的空间分布及其变异状况。在本研究中,我们在中国广西壮族自治区西南部的热带林业实验中心,布设了181个样点并进行了采样,应用地统计学方法研究了土壤中氮磷钾和有机质的空间变异性。块金值与基台值的比值表明土壤中氮具有很强的空间依赖性,主要受内在因素影响(如土壤质地、母质、植被类型和地形),而土壤中有机质、磷钾具有中等的空间依赖性,受内在因素和外在因素(如栽培技术、施肥和种植模式)共同影响。在土壤中氮磷钾和有机质的空间变异性的基础上,本研究采用普通克里格方法进行空间插值,制作了土壤氮磷钾和有机质空间分布图。模型验证表明,土壤性质空间分布图能够可靠地指导森林经营活动。