A 60 day trial of turf grass, with reasonably constant weather conditions. The change in slope of the root zone water content is clear, although the depth profiles showed that after this time the crop started to use water below 70 cm and it did not show signs of stress. However, there would have been a reduction in yield.
This particular example is also interesting in that the irrigations applied at the end of the trial did not return the profile to the full point. The soil is a cracking clay, and. as water enters the profile the clay expands, the cracks close, and water cannot penetrate. The permeability of these clays when they are intact is extremely low, and water penetration is almost totally along cracks.