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 well structured having a low bulk density of 1.16 g/cm³, a high saturated hydraulic conductivity of 135 mm/hr, and a very high drainable porosity of 21.2 % which is well in excess of the ideal level of 10 %. Despite the excellent structure of the topsoil, it holds a relatively small amount of water for tree growth. The A1 horizon contains 16.4 % or 19.7 mm plant available water (PAWC), of which 8.1 % or 9.7 mm is readily available to support rapid growth (green Figure 3), an additional 9.9 mm soil moisture is available to the tree but at a cost to growth (Orange Figure 3), whilst 23.2 mm is not able to be used by trees (Red figure 2). The B21 and B22 horizons are similar to each other. The B21 has moderate bulk density at 1.30 g/cm³ yet has ample drainable porosity for a subsoil at 9.8 %. The readily available soil moisture of the B21 horizon is only 5.1 % or 10.2 mm which is slightly greater than that of the B22 horizon at 4.5 %. The majority of the soil moisture in the B21 and B22 horizons at 28.2 % and 30.9 % respectively is not available for plant water extraction (red in figures 2 and 3).