兰州市南北两山不同灌丛土壤渗透特性

为了探讨不同灌丛类型对土壤渗透特性的影响,通过双环渗透法对兰州市南北两山4种灌木类型(千头柏、红砂、红花锦鸡儿、柽柳)的土壤渗透特性(土壤初渗率、稳渗率、平均渗透速率和渗透总量)进行了研究。结果表明:(1)随着土层深度(0—80 cm)的增加,土壤的渗透性逐渐降低。(2)不同灌丛类型间土壤渗透性表现为红花锦鸡儿>红砂>千头柏>柽柳,主成分分析评价土壤的渗透能力,排序为红花锦鸡儿>红砂>千头柏>柽柳;(3)Horton模型方程对各灌丛类型土壤渗透性的拟合效果最好,比较适合于描述本研究区4种灌丛土壤水分入渗过程。(4)土壤渗透性和土壤理化性质的相关性分析表明,土壤渗透性与总孔隙度、土壤有机质含量、土壤全氮、土壤无机氮、土壤速效磷、土壤速效钾之间分别呈极显著正相关; 与土壤初始含水率、土壤非毛管孔隙度之间分别呈显著或极显著正相关; 与土壤容重呈极显著负相关。(5)结合相关性分析,筛选出9个极显著或显著影响土壤渗透性的土壤理化性质因子,综上,结果为今后该区域在人工林营建过程中树种的选择及现有林分抚育管理提供一定的理论依据。

Soil Infiltration Characteristics Under Four Shrub Types in Southern and Northern Mountains of Lanzhou City

Soil infiltration characteristics including initial infiltration, stable infiltration, average infiltration and accumulative water quantity were studied under four different shrub types including Platycladus orientalis cv. sieboldii,Reaumuria soongorica, Caragana rosea and Tamarix chinensis in southern and northern mountains of Lanzhou City based on double ring infiltration method. The results showed that soil infiltration characteristics decreased with the increase of soil depth in the 0—80 cm soil layers; the soil infiltration characteristics under different forest types were in the following order: C. rosea>R. soongorica>P. orientalis cv. sieboldii>T. chinensis, while the order was the same among shrubs using principal component analysis. The Horton infiltration model gave the best performance on the infiltrating processes in the four shrub types, followed by Common empirical, Philip and the Kostiakov model. Correlation analysis between soil infiltration characteristics and soil physical and chemical properties showed that soil infiltration characteristics had extremely significant positive correlations with total porosity, soil organic matter, soil total nitrogen, mineral nitrogen, available phosphorus, available potassium, and had significant positive correlations with soil water content, noncapillary porosity, and had significant negative correlation with soil bulk density. Based on the correlation analyses, nine factors which have extremely significant or significant effect on soil infiltration capability were selected. These research results may be useful for providing a theoretical basis for the selection of tree species in the construction of artificial forests in the northern and southern mountains of Lanzhou City.