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以塔里木河下游河岸带生长良好具有代表性的胡杨为供试植被,利用土壤水分特征曲线的分形结合胡杨根系分布函数的方法,对根区土壤水分和根长根系吸水关系进行了研究,确定了土壤水分特征曲线和非饱和土壤导水率。根据干旱区胡杨根系分布特征建立了干旱区胡杨二维根长密度函数。所建根长密度函数在根层近地表处服从抛物面分布,而在根层下部服从指数面分布,并基于二维改进的Feddes模型,建立了胡杨根系吸水的二维数学模型。结果表明,春季、夏季、秋季、冬季实验区胡杨根区土壤水分模拟值与实测值的平均误差依次分别为4.0%、7.2%、5.9%、4.9%,均低于10%,得到了较好的模拟效果。这进一步提升了干旱区植物根系吸水模型的模拟精度,为干旱区自然植被耗水量的计算提供了新的方法和科学依据。因此,该二维模型在干旱区植物耗水计算中具有广泛的应用价值和现实意义。
Taking the Populus euphratica growing well along the bank of the lower reaches of the Tarim River as the test vegetation, the relationship between water content in the root zone soil and water absorption in root length roots was studied by using fractal characteristics of soil water characteristic curve and root distribution function of Populus euphratica. Soil water characteristics curve and unsaturated soil hydraulic conductivity. According to the root distribution characteristics of Populus euphratica in arid area, the two-dimensional root length density function of Populus euphratica in arid area was established. The root length density function obeys the paraboloid distribution near the surface of the root layer and the exponential surface distribution under the root layer. The two-dimensional mathematical model of root water absorption of Populus euphratica is established based on the two-dimensional Fedood model. The results showed that the average errors between simulated and measured values of Populus euphratica in the experimental area of spring, summer, autumn and winter were 4.0%, 7.2%, 5.9% and 4.9%, respectively, all less than 10% The simulation effect. This further enhances the simulation precision of plant root water uptake model in arid area and provides a new method and scientific basis for the calculation of water consumption of natural vegetation in arid area. Therefore, this two-dimensional model has extensive application value and practical significance in the calculation of plant water consumption in arid areas.