Soil moisture response, steady-state SPAC approach

The degree of potential water uptake as a function of pressure head with different atmospheric demands and different root densities.

High demand, low root density = green.   Low demand, low root density = red.

High demand, high root density = blue.    Low demand, high root density = turq.

The figures are the result of estimates based on a sandy soil from one horizon in the middle of the root zone. The low root density corresponds to a total root length of 1 km/m² and the high root density corresponds to 50 km/m².