论文部分内容阅读
利用水平土柱入渗法对科尔沁沙地的草地、固定沙丘和流动沙丘0~20 cm土层的土壤水分扩散率(D(θ))与土壤体积含水量(θ)之间的关系进行了测定,并建立了D(θ)和波尔兹曼参数(λ)与θ的定量关系。结果表明:(1)不同类型沙地0~20 cm土壤湿润峰迁移速率以草地的最小,其次为固定沙丘,而流动沙丘的最大,平均值分别为0.38、0.70和1.45 cm min-1;而且三类沙地土壤湿润峰迁移速率随入渗距离呈对数形式递减;(2)随着土壤体积含水量θ的增加,波尔兹曼参数λ逐渐减小,而且当θ达到某一临界值之后,λ急剧减少;(3)三类沙地D(θ)以草地和固定沙丘的较低,平均值分别为1.44和1.43 cm2min-1,而流动沙丘的较高,平均值为2.88 cm2min-1;土壤水分扩散率与土壤体积含水量的关系符合经验公式D(θ)=aebθ;(4)对科尔沁沙地土壤水分扩散率影响较大的土壤理化性质主要是有机质含量和粘粉粒含量。
The relationship between soil water diffusivity (D (θ)) and soil volumetric water content (θ) in 0-20 cm soil layer of grassland, fixed sand dune and mobile sand dune in Horqin sandy land was studied by horizontal soil column infiltration method The quantitative relationship between D (θ) and Boltzmann parameter (λ) and θ was established. The results showed as follows: (1) The wetting peak migration rates of 0-20 cm soil layer in different types of sandstones were the lowest in grassland, followed by the fixed sand dunes, while the maximum values of moving sand dunes were 0.38,0.70 and 1.45 cm min-1, respectively (2) The Boltzmann parameter λ decreases with increasing θ of soil volumetric volume, and when θ reaches a certain critical value (3) The mean values of D (θ) for grassland and fixed sand dune in the three types of sandy land are 1.44 and 1.43 cm2min-1, respectively, while those in the moving dunes are 2.88 cm2min- 1. The relationship between soil moisture diffusivity and soil volumetric water content accorded with the empirical formula D (θ) = aebθ. (4) The physical and chemical properties of soil that had a great influence on soil moisture diffusivity in Horqin sandy land were mainly organic matter content and sticky grain content .