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.

Overall the topsoil or A1 horizon has moderate structure and water retention properties. The A1 horizon has a low bulk density of 1.19 g/cm³, and exceptionally high saturated hydraulic conductivity at 450 mm/hr. However, the drainable porosity at 8.7 % is less than the ideal value of 10 %. This indicates that while there are slightly less than the desirable number of macropores, they are highly connected and functioning well. The B21 horizon is moderately compact at 1.44 g/cm³, and has only around half the desired drainable porosity at 5.1%. The saturated hydraulic conductivity of the B21 horizon is 0.5 mm/hr compared to 450 mm/hr in the A1 horizon. This indicates potential for the development of perched watertables and subsurface lateral flows. The B22 horizon has only 1.1 % drainable porosity such that when moist low oxygen conditions are likely to develop and persist for some time. Notably over half the soil water held in the B21 and B22 horizons is not available for tree use.