三江平原典型草甸小叶章湿地土壤水分扩散率研究

运用水平土柱入渗法模拟研究了三江平原典型草甸小叶章湿地土壤的水分扩散过程以及水分扩散率与土壤含水量之间的关系。结果表明:草甸沼泽土各土层的含水量与Boltzmann常数分别符合不同的关系曲线,且差异主要与粘粒含量和基质势有关;各土层的Bo-ltzmann常数自表层向下依次降低,且差异达到极显著水平(p<0.01);草甸沼泽土各土层的水分扩散率存在较大差异,0-20cm土层最高,30-40cm土层最低;草甸沼泽土与盐碱化沼泽土、人工湿地水稻土的水分扩散率存在显著差异,原因与不同类型土壤各土层的理化性质及理化过程有关;草甸沼泽土各土层的水分扩散率随土壤含水量的增加均呈指数增长曲线变化,且表层土壤的增长曲线相对较陡。

Soil Water Diffusivity in the Typical Meadow of Calamagrostis Angustifolia Wetland in Sanjiang Plain

The water diffusion processes and the relationships between water diffusivities and soil water contents in typical meadow Calamagrostis angustifolia wetland soil in Sanjiang Plain were simulated by horizontal soil column infiltration method.The results showed that the relationships between water contents and Boltzmann constants in different solums varied in different curves,and the differences were mainly correlated with clay content and sol matric potential.The Boltzmann constant was higher in topsoil and decreased as soil depth increasing,and the values among different solums were significantly different(p<0.01).The water diffusivities of solums were different,and the value of 0-20cm solum was higher than that of other solums.Further analysis indicated that the water diffusivity of meadow marsh soil were significantly different with that of saline-alkaline soil and paddy soil,and the reasons were mainly correlated with the physical and chemical properties and processes of different types of soils.Moreover,the water diffusivities of different solums increased by exponential growth curves with the increase of water contents,and the increase curve of topsoil was steeper.