Soil Water Flux below a Ryegrass Root Zone1

The net water flux below the root zone of a rye grass crop was measured in the field for plots receiving equal total quantities of irrigation water but applied in unequal amounts at different frequencies. Hydraulic conductivity values calculated from field‐measured soilwater potential gradients and laboratory‐measured soilwater characteristics were used to compute the soilwater flux. The amount of water moving into or out of the root zone was influenced by the irrigation frequency. The nature of the hydraulics of a natural field soil, its variability in space, and its implications for the interpretation of soil‐water depletion data are also provided.