Soil Hydrology Overview

This data reflects both the quality of the soil structure, the amount of water available for growth and the ease by which these soils are able to be irrigated. The data indicates how much water is available for vigorous tree and fruit growth, as well as how much water is available for tree maintenance and survival. This data can also be used to better schedule irrigation, and compare irrigation requirements between soils.

The topsoil (A11 horizon) appears to be moderately compact having a bulk density of 1.39 g/cm³ in the A1 horizon and 1.44 g/cm³ in the A12 horizon, and a below optimal drainable porosity at only 2.5 % and 3.0 % in the A11 and A12 horizons, whereas the ideal drainable porosity for a topsoil is around 10%. Despite this evidence of compaction and a lack of macroporosity, the hydraulic conductivity at 363 mm/hr is very high, which indicates that while there is not a great deal of soil porosity, what is there is functioning well. The A11 and A12 horizons hold similar amounts of plant available water (PAWC) at 27.9 % and 25.3 %. However, as a proportion of the total soil water, these soil horizons hold very little readily available soil water at 6.5 % and 7.6 % respectively. These horizons do however contain a large amount of tightly held soil moisture at 21.4 % and 17.7 % which is available for tree function and survival but not rapid growth. The two B horizons have a high proportion of unavailable soil water which trees cannot access at 23.9 and 34.5 %, and very little drainable porosity at 1.6 % and 0.7 %, and little readily available soil moisture at 3.1 and 2.1 %.