金沙江干热河谷典型林草植被下坡面土壤水分分布控制因素

Dominating Factors of Soil Moisture Distribution in Typical Forest Vegetation Slopes in Dry Hot Valley Area of Jinsha River

基于2016年7月使用土钻法采集金沙江干热河谷区典型林草植被(银合欢(Leucaena leucocephala)人工林地、车桑子(Dodonaea angustifolia)灌丛地和扭黄茅(Heteropogon cantortus)草地)下的土壤含水量数据,利用植被生态数量学中的冗余分析法(RDA)和SPSS统计分析法,分析了坡面尺度上各立地环境因子与土壤(0~100cm)水分的相关关系,筛选出影响3种林草植被下土壤水分的控制因素。结果表明:不同典型林草植被土壤水分波动程度不同,土壤水分变动范围为14.41%~23.97%,变异系数(V_C)为0.22~0.94,属中等变异(0.1<V_C<1.0),均值由大到小表现为灌丛地(11.62%)、林地(7.72%)、草地(6.66%);3种典型林草植被各环境因子对土壤水分前2轴的累积百分比变化率均达到93%以上,各环境因子对土壤水分有不同程度的影响,其中黏粒、有机质、密度、饱和持水量、粉砂、pH值和磷钾对坡面土壤水分影响最为显著,林地受密度、速效钾、黏粒、速效磷、有机质的影响显著,是林地土壤水分主控因素;而灌丛地受饱和持水量、pH、全磷、黏粒、粗粉砂的影响显著;草地则主要受中粉砂、速效钾、黏粒、有机质的影响显著。

With the data of soil moisture under typical forest vegetation(Leucaena leucocephala forest,Dodonaea angustifolia shrub land and Twig grassland)in dry hot valley area of Jinsha River,by the redundancy analysis in the quantitative study of vegetation ecology and statistical analysis,the correlation between environmental factors and soil moisture(0-100 cm)on slope scale was studied,and the dominating factors of soil moisture under 3 forest vegetation were screened out.The soil moisture fluctuation degree of different typical forest vegetation is different,the range of soil moisture variation is 14.41%-3.97%,and coefficient of variation is 0.22-0.94.It is moderately variable(0.1<CV<1),and the average soil moisture content is with shrub land of 11.62%,forest land of 7.72%,and grassland of 6.66%.Three kinds of typical forest vegetation of the environmental factors on soil moisture before the cumulative percentage change in the two axis rate reached more than 93%,and the environmental factors had different effects on soil moisture.Among them,clay,organic matter,soil bulk density,saturation moisture capacity,silt,pH and P and K had the most obvious effects on soil moisture,and forest land was affected mainly by soil bulk density,quick results K,clay,quick results P and organic matter.It was the dominating factor of soil moisture in forest land.The shrub land is affected by saturation moisture capacity,pH,total P,clay and coarse silt,which determines the soil moisture of shrub land to a certain extent.The grassland is mainly affected by medium silt,quick results K,clay and organic matter.