Formation of the Optimum Mass Transfer System in Agricultural Land

为了明确农用地物质循环的最佳条件，对土壤中水分、溶质和微固体的耦合运动进行了研究和分析。溶质运移方面的工作：土壤中溶质浓度的四种方法是新提出的。通过大量数据系统地展示了土壤蒸发积盐、含盐地下水碱化过程和施钙复垦碱化土壤的过程。结果表明，可以用考虑土壤中离子交换的同时输运数学模型来分析结果。微固体运移方面的工作：在含有悬浮粘土颗粒的水渗入土壤的情况下，显示了土壤中微固体的捕获现象。这些数据有助于理解土壤渗漏量的减少，并有助于理解土壤清水的机理。关于渗透的著作I…多层土：展示了土层间的边界线在下层形成的特征流动，并在二维平面上分析了流动方向。水蚀方面的工作：观测了降雨条件下结皮的物理性质，详细说明了结皮的低渗透性对土壤侵蚀量的影响。其他与生物有关的工作：设计了测量植物根伸长力和伸长率的方法，并进行了测量。得到了力与土壤硬度之间的关系，它是含水量的函数。通过对旱地微生物活动的研究，发现其对土壤水分入渗的影响，在此基础上，建立了水分、溶质和固体颗粒同时运动的数学模型，并由东京大学出版社出版，以方便利用。较少

In order to make clear the optimum conditions of materials circulation in agricultural land, the coupling movement of water, solutes and micro-solids in soil were examined and analyzed.1. The works on solute transport : The four-method was newly devised to solute concentration in soil. The salt accumulation in soil by evaporation, the process of soil sodicification by groundwater containing salts, and the reclamation process of sodic soils by applying Calcium were systematically shown through much data. It was shown that the results could be analyzed by using a mathematical simultaneous-transport model considering ions exchange in soil.2. The works on micro-solids transport : The captured phenomena of micro-solids in soil were shown in the case which water containing the suspended clay particles infiltrated into soil. The data resulted in understanding the decreases of soil percolation and in understanding the mechanisms of water clearing by means of soil.3. The works on infiltration i … More nto layered soil : That the boundary lines between layers in soil made a characteristic flow in lower layer was shown, and the direction of flow was analyzed in two-dimensional planes.4. The works on water erosion : The physical properties of crusts formed under rainfall were observed and it was shown in details that the low permeability of crusts affected on the amount of eroded soil.5. The works on the others concerning living things : The method measuring the force and rate of plant root elongation was devised and the measurements were carried out. The relationships between the force and soil hardness were obtained as functions of water contents. The activities of microorganism in uplands were wxamined and it was shown that they affected on water infiltration into soil.On basis of the above results, the system of simultaneous movement of water, solute and solid particles was constructed as a mathematical model and published by the Tokyo University Press in order to make its utilization convenient. Less