测定滨海盐渍土的土壤水分特征曲线及相应的参数,为研究和模拟水盐运移提供可靠的参数依据。以中国科学院黄河三角洲滨海湿地生态实验站内的盐渍土为例,使用压力膜仪测定土壤吸力和水分的关系,根据Brooks-Corey、Gardner和van Genuchten 3种模型拟合土壤水分特征曲线,结果表明:van Genuchten模型拟合的精度最高,剖面五层土壤的决定系数都大于0.97,与试验点土壤质地无明显相关性,可以用于该地区的土壤水分特征曲线拟合;BrooksCorey和Gardner模型的拟合效果相似,且精度波动都很大,在砂性土范围内,决定系数大小与土壤物理性砂粒含量成反比,不适合用于由泥沙堆积而成的黄河三角洲地区的土壤水分特征拟合。van Genuchten模型拟合结果表明:不同土壤的水分特征曲线不同,同一质地类型的土壤具有相似的曲线形状;土壤颗粒的粒径组成和含盐量对土壤的持水性有很大的影响,土壤颗粒越大土壤持水性越差,土壤含盐量越高,土壤持水性越好。
The soil moisture characteristic curve and the homologous parameters are measured, and a reliable parameter basis is pro vided to study and simulate water and salt transport. The salinized soil from Yellow River Delta Ecologic Research Station of Coastal Wetland of CAS is used as a sample to measure the relationship between the soil suction and moisture by using pressure membrane method and fitting the soil moisture characteristic curve with the Brooks-Corey model, Gardner model and van genuchten model. The results show that the Van Genuchten model has the highest fitting precision, all the coefficients of determination coefficient of deter mination of the section's five level soils are more than 0.97, and they had no significant correlation between the soil textures of the testing point, the model could be used for fitting the soil moisture characteristic curve of this region; the imitative effects between Brooks-Corey model and Gardner model were similar and their fitting accuracies fluctuated largely, the two models' coefficients of determination were inversely proportional to the content of physical sand soil of the edaphic, so they all were not suitable for fitting the soil moisture characteristic curve of the Yellow River Delta which was heaped up by silt. The results fitted by van Genuchten model showed that different edaphic had different soil moisture characteristic curve and edaphic which had the same texture had the similar curse shape; the particle size of particles and the salt content of edaphic made a great difference on the water-binding capacity of edaphic, the bigger the soil particle was, the worse the water-binding was and the higher the salinity was, the better the water-binding.