应用三维图像和数学模型对土壤团聚体内外溶质的交换速率的研究

发布时间：2019-07-05 07:05

【摘要】：受土壤有机质和微生物的影响,大部分农业土壤都有团聚体结构。团聚体内部的孔隙一般很小,与团聚体之间的水流相比,团聚体内部的水可以视为不动的。但受质量浓度梯度和分子扩散的影响,2个水体内的溶质可以相互交换。模拟溶质在具有团聚体结构土壤中运移时,溶质在以上2个水体间的交换过程常用可动-不可动水体模型来描述。土壤溶质运移涉及的参数较多,很多参数不能直接测定,要靠观测值拟合才能获得。由于不同的参数组合可以得出相同溶质质量浓度分布,因此,即使模拟结果和实验结果吻合也不能确保该模型正确描述了2个水体之间的溶质交换过程。为了深入研究这一问题,利用三维图像技术和数学模型,计算了团聚体内外溶质交换速率。结果表明,Coats-Smith模型误差很大,2个水体之间的溶质交换速率并非与其质量浓度差成正比。作为改进,提出并证明广义γ分布函数可以准确地描述团聚体内外溶质交换过程。
文内图片：

图片说明：二维团聚体土壤切片
[Abstract]:Affected by soil organic matter and microorganisms, most agricultural soils have aggregate structure. The pores in the aggregates are generally very small, and compared with the flow between aggregates, the water in the aggregates can be regarded as immobile. However, due to the influence of mass concentration gradient and molecular diffusion, the solute in the two water bodies can be exchanged with each other. When simulating solute transport in soil with aggregate structure, the exchange process of solute between the above two water bodies is described by movable and immovable water body model. There are many parameters involved in soil solute transport, many of which can not be measured directly, but can only be obtained by fitting the observed values. Because the same solute mass concentration distribution can be obtained by different parameter combinations, even if the simulation results are consistent with the experimental results, the model can not correctly describe the solute exchange process between the two water bodies. In order to study this problem deeply, the solute exchange rate inside and outside the aggregates was calculated by using three-dimensional image technology and mathematical model. The results show that the error of Coats-Smith model is very large, and the solute exchange rate between the two water bodies is not proportional to the difference of mass concentration. As an improvement, it is proposed and proved that the generalized gamma distribution function can accurately describe the solute exchange process inside and outside aggregates.
【作者单位】：济源职业技术学院;华北水利水电大学;
【分类号】：S152

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