红壤坡地生态系统土壤入渗特征比较研究

以亚热带红壤区6个典型坡地生态系统为研究对象,采用盘式负压入渗法,系统研究了红壤的入渗过程、特征及其与土壤主要理化性质的关系.选择的生态系统包括:农田(包括缓坡农田和陡坡农田各一块)、草地、灌丛、茶园、常绿落叶阔叶混交林、油茶林等.结果表明:各生态系统土壤入渗率随时间的变化均可拟合为幂函数形式.不同生态系统稳定入渗率变化范围为0.024～0.080 mm/min,其中农田和油茶林的稳定入渗率较大,草地和茶园的最小.稳定入渗率与土壤容重及初始含水量呈显著负相关,而与孔隙度呈正相关.入渗过程主要受孔隙度和黏粒含量的影响.土壤有效孔径和宏观毛管长的变化范围分别为0.064～0.179 mm和41.5～128.2 mm,但统计显示其与土壤主要理化性质之间的相关性均不显著.

Comparison Study on Soil Infiltration Characteristics in Red Soil Slope Ecosystems

Soil infiltration characteristics, process and their relationship with soil main physical and chemical properties were studied. Six typical slope ecosystems in subtropical red soil region were selected and disc permeameter method was used. The selected ecosystems comprised of cropland (including steep and gentle slope types), grassland, shrub, tea garden, mixed evergreen and deciduous broadleaf forest, oil-tea (Camellia oleifera), woodland. Results showed that the relationship between soil infiltration rate and time in each ecosystems could be fitted as Y=aX~(-b)(P<0.01). The stable infiltration rate (Is) in all ecosystems ranged from 0.024 to 0.080 mm/min, while Is was the highest in cropland and oil-tea woodland but the lowest in grassland and tea garden. Is was negatively correlated to soil bulk density, initial moisture, but positively correlated to soil porosity. Infiltration process was mainly affected by soil porosity and clay content. The range of soil mean available pore size (MAPS) and macro-capillary length (MCL) were 0.064～0. 179 mm and 41.5～128.2 mm respectively. However, MAPS and MCL were non-significantly related to main soil physical and chemical properties.