Einfluß der Saugspannung auf den Wasserentzug durch die Wurzeln einer Grasvegetation

Relations between root water uptake and soil moisture tension . The root water uptake Q expressed as sink term of the continuity equation was computed using exclusivly field measured data of a post-irrigation water transport study. The experiment was carried out in an undisturbed Loess soil monolith. The soil moisture redistribution influenced by the evapotranspiration of the grass cover and the soil moisture characteristics were measured independently using the identical experimental layout. The data show a clear relationship between the root water uptake Q and the soil moisture tension S. Within the tension range of approx. 0–100 mbar the uptake Q decreases drastically with water desaturation. Within the upper part of the rooting zone this decrease is more pronounced and starts at a lower tension.