黔中马尾松成熟林表层土壤养分与林分结构的异质性及其耦合关系

Heterogeneity and coupling relationship of soil nutrients and forest structure in the mature forest of Pinusmassoniana in central Guizhou

在贵州省安顺市平坝区马尾松成熟林中设置82个10 m×10 m的网格样地,选取土壤有机质、全氮、全磷、全钾、速效氮、速效磷和速效钾等土壤养分指标以及郁闭度、蓄积、密度、胸径多样性指数和树高多样性等林分结构,应用描述性统计、半变异函数方法分析土壤养分及林分结构的异质性特征,应用典型RDA排序方法研究土壤养分与林分结构间的相互作用,以期探明黔中地区马尾松成熟林中土壤养分及林分结构间的耦合关系.结果表明:土壤养分变异系数为16.728%~35.167%,林分结构为11.641%~50.871%,均属于中等变异程度;土壤养分与林分结构均存在强烈的自相关,土壤养分自相关范围为7.800~22.191 m,林分结构为11.40~19.75 m;土壤有机质和速效钾两种土壤养分指标对林分结构的影响最显著,说明这两种土壤养分元素对马尾松林木的分布、生长及发育影响较大.其中,有机质显著影响蓄积、胸径多样性指数和郁闭度;速效钾显著影响树高多样性指数和密度.

Eighty-two plots of 10 m × 10 m grid plots were set up in the mature forest of Pinusmassoniana in Pingba District of Guizhou Province. Soil nutrients such as soil organic matter,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus,and available potassium were selected. For the stand structure,stock accumulation,density,DBH diversity index and tree height diversity,descriptive statistics and semi-variogram methods were used to analyze the heterogeneity of soil nutrient and forest structure,and the soil was studied using a typical RDA ranking method. The interaction between nutrients and stand structure was used to explore the coupling relationship between soil nutrients and stand structure in Pinusmassoniana mature forests in Central Hebei Province. The results showed that the coefficient of variation of soil nutrients was 16.728%-35.167%,and the stand structure was 11.641%-50.871%,all of which belonged to moderate degree of variation. There was strong autocorrelation between soil nutrient and stand structure,and the soil nutrient autocorrelation range was 7.800-22.191 m,the stand structure was 11.40-19.75 m; soil organic matter and available potassium had the most significant effect on the stand structure,indicating that the effects of these two soil nutrient elements on the distribution,growth and development of Pinusmassoniana forests were larger. Among them,organic matter significantly affected the accumulation,the DBH diversity index,and canopy closure; the available potassium significantly affected the tree height diversity index and density.