Abstract
Roots are often observed to grow in cracks formed in clayey subsoil. Water content gradients in these cracks, however, have not been examined under field conditions. We calculated the soil water content in the vicinity of the cracks in a field based in Richards' equation. Field experiments showed that there was no gradient when the average soil water content was -0.1MPa (Fig.1).Calculation showed that the soil water content gradient near the roots was very small for a soil water content exceeding -0.1MPa and that it became larger when the water absorption rate increased due to the high root density (Fig. 2). The results obtained confirmed that the soil water content gradient in the subsoil decreased uniformly regardless of the distance from the crack wall with roots.
