Adhesive water

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Haftwasser referred to bottom against the gravity held water , the smaller pores 10 microns by the surface tension of the water adheres. Roughly speaking, these are the medium and fine pores of the soil.

Adhesive water represents soil moisture in the narrower sense. The term soil water , on the other hand, also includes the proportion of water-saturated soil that can run off as seepage water .

The capillary water , which is held by menisci (concavely curved water surfaces), and the adsorption water , which is attached to the surface of soil particles without forming menisci, are counted as retained water . Water in fine pores is so strongly bound that it can hardly be absorbed by plants ( dead water ). In contrast, the water in the central pores is available to plants and represents the measure of the water availability of a location ( usable field capacity ). Plants use the retained water in dry periods for their water supply up to the " wilting point ".

Retained water content in soils

The more surface-active and porous organic substance there is in the soil, the more adhesive water it has, because humus colloids bind more adhesive water than clay minerals .

Soils with rather fine texture , so ton - or schluffreiche floors, have more retained water than sandy , in which seeps most of the water. In extremely silty soils, so much water can be bound in the central pores that conditions such as waterlogging with hydromorphic features (rust spots) arise. This is the case with soils of the type pseudogley .

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