撒施肥料一维畦灌地表水流与溶质运移模型构建与验证

One-dimensional model development and validation of surface flow and solute transport for border irrigation in traditional surface fertilizer application

模拟撒施肥料下的一维畦灌地表水流与溶质运移过程可为采用先进的畦灌液体施肥方式提供对比依据。该文基于湍流理论垂向流速线性与对数分布规律及不可压缩流体力学连续方程,构造沿畦长及任意垂向断面的非均布流速场和溶质浓度场,建立起撒施肥料下的一维畦灌地表水流与溶质运移模型,并利用典型畦灌施肥试验结果,检验该模型的模拟效果。结果表明,建立的模型不仅具有在撒施肥料状况下较好模拟地表水流运动和溶质浓度时间变化过程的能力,还具备较佳的水量和溶质质量守恒性,从而为评价撒施肥料下的畦灌施肥系统性能及与其它施肥方式下的畦灌施肥系统性能对比,提供了实用的数值模拟工具。

A comparison basis can be provided for the advanced border fertigation application by simulating one-dimensional surface flow and solute transport process of border irrigation in traditional surface fertilizer application. A non-uniform distribution field of water flow velocity and solute concentration along the basin and its arbitrary vertical cross-section were constructed based on the vertical linear and logarithmic law in turbulence theory and continuous equation of incompressible hydrodynamics. A one-dimensional surface flow and solute transport model for border irrigation in traditional surface application of fertilizer was proposed. At the same time,validation of the proposed model was carried out using the results of two typical border irrigation tests. Results show that the proposed model can successfully simulate the water flow and solute transport processes of border irrigation,and exhibits good potential for use in conservation of water and solute quantities. Consequently,the proposed model provides a practical numerical tool for evaluating the performance of border irrigation in traditional surface application of fertilizer,and serves as a basis for comparison of border irrigation systems in different manners of fertilizer application.