1,720,992 research outputs found
Exploitation of the principles governing salt and water movement in clay soils in order to develop a method of reclamation
No full textSalt movement in clays and the importance of diffusion to it are discussed. Diffusion, shown to be the main process by which salts move from the poorly permeable mass of the soil to the network of macropores in which drainage occurs, is a relatively slow process. But is not as much a limiting factor on the leaching of salts from clays as poor internal drainage. Laboratory and field investigations have shown that salts can be rapidly leached from clay soils if the soils are restructured into smaller units so that the salt is more accessible and the soil more permeable. However the improved soil structure is adversely affected by soil overburden weight and by the soil slaking which occurs when the soil is first wetted. Accordingly, the maximum depth for such restructuring is between 500 and 800 mm, and the moisture content at the time of first wetting should also not be allowed to fall below 24% w/w.<br/
Economic considerations influencing the choice of surface or subsurface drainage systems in heavy soils
No full textHydraulic Design in Water Resources Engineering: Land Drainage: Proceedings of the Second International Conference, Southampton University, UK, April 1986
No full textWater stability tests on clay soils in relation to mole draining
No full textChilds' method of using moisture characteristic curves of clay soil aggregates as a test of their water stability was investigated as a means of identifying soils that are suitable for mole draining. The results of the test applied to a soil in which mole drains are known to last many years and to one in which they are known to fail shortly after being drawn, were used to assess the suitability of a third soil, taken from two locations a distance of 30 km apart, for mole draining. The tests on a given soil were reproducible on samples collected from different sites over a field except in one case when slaking of the sample during the test resulted in the surface's sealing and an anomalous moisture characteristic curve
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