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 upper topsoil (A1 horizon) appears to be moderately compact having a bulk density of 1.33 g/cm³, and a very low drainable porosity at only 3.3 %, whereas the ideal value for a topsoil is 10 %. However, the hydraulic conductivity at 249 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 A1 horizon has only 8 % or 30.5 mm readily available water to support rapid tree growth. The majority of water in this soil layer being either unavailable at 18.1 % or too tightly held at 18.8 % for rapid growth but available to prevent droughting. The 2A1 is a buried soil horizon which probably was the original A1 horizon. The 2A1 is noted to have 10.7 % drainable porosity which is ideal and substantially greater than the A1 horizon at only 3.3 %. This provides further evidence that the surface A1 horizon is compact.

The two buried B horizons (subsoils) have very little drainable porosity at 3.7 % and 1.9 %, and very low hydraulic conductivity at 0.15 to 0.03 mm/hr. These soil layers are very slow and poorly drained, even when drained to field capacity they have little capacity for storing oxygen needed for root growth. The mottle colours also indicate these soil layers are seasonally waterlogged. Somewhat surprisingly the subsoils hold proportionally more plant available water content and readily available water than the two A1 horizons.