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 (A1 horizon) appears to be moderately compact having a bulk density of 1.40 g/cm³, and a low to moderate saturated hydraulic conductivity of 50 mm/hr. These measures would normally indicate compaction or loss of soil structure, however the A1 horizon has 12.4 drainable porosity which is over the recommended 10 % and indicates good aeration and drainage capacity. The A1 horizon also has a very large proportion of readily available soil moisture at 18 % or 35.9 mm for tree growth, and a further 8.0 % or 15.9 mm tightly held soil moisture which trees are able to use but at a cost to growth rate. The A21 horizon also has exceptional moisture retention properties, the major difference between the A1 and A2 horizons is the lower drainable porosity at 7.4 % in the A2 horizon. Together the A1 and A21 horizons contain 36.4 mm of readily available soil water and a PAWC of 52.4 mm.

The B21 and B22 horizons are very different to the A1 and A2 horizons. at least half the soil moisture in the subsoil B21 and B22 horizons is not available for tree use, with only a small amount of water being readily available at 12.5 mm and 11.5 mm respectively. Somewhat surprisingly the B21 horizons have a moderate amount of drainable porosity at 7.2 % and 5.5 % indicating moderate conditions for root growth.