松嫩平原苏打盐渍土土壤水分特征研究

以苏打盐化草甸土和苏打碱土2 种土壤类型为研究对象,研究苏打盐渍土土壤水分特征,并对土壤水分特征曲线进行模拟。结果表明,0~40 cm土壤层,盐化草甸土总孔隙度大于50%,毛管孔隙中以0.1~1.2 mm当量孔径的粗孔隙为主,苏打碱土总孔隙度低,主要以小于0.1 mm当量孔径的细孔隙为主;0~40 cm土壤层在相同水势作用下,盐化草甸土土壤含水率明显高于苏打碱土,说明苏打碱土土壤持水能力较低。通过模型模拟,获得不同土壤层的水分特征曲线参数,模拟值与实测值相关系数均在0.9 以上,模型具有可靠性。

Soil Water Characteristic of Saline-sodic Soil in Songnen Plain

A soil water characteristic curve (SWCC) defines the relationship between soil water potential and soil water moisture. SWCC is one of the main tools used to model soil water and solute transport. Soil water characteristic curves were directly affected by different soil physical and chemical properties in saline-sodic soil. In this experiment soil water characteristics were studied for the two soil types (saline meadow soil and alkaline- sodic soil). Soil water potentials were simulated and soil water characteristic curves were drawn by Levenberg- Marquardt and global optimization calculating method. The results showed that change on soil moisture of saline meadow soil is obvious under different water potential, soil moisture in 0-40 cm soil layer is significantly higher in saline meadow soil than alkaline-sodic soil under the same soil water potential. For saline meadow soil, the total porosity was bigger than 50%,porosity of macro capillary (equivalent pore: 0.1-0.1 mm) can exceed 70% of total porosity. Total porosity was lower in alkaline-sodic soil, which hold the highest amount of micro pores (equivalent pore:＜0.1mm). Soil water-holding ability seriously low for alkaline-sodic soil. The modeling results showed a good agreement with the observed data, and captured the generally trend of the observed data. The calculated correlation between the simulated and observed data was above 0.9, decision coefficients were over 0.86, indicating the good match between modeled and observed results. The results from this research can provide basic parameters for soil water and salt movement simulation in saline-sodic soil area.