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 surface A11 horizon has good soil structure and water retention properties. The A11 horizon has a moderate bulk density of 1.24 g/cm³, an exceptionally high saturated hydraulic conductivity at 500 mm/hr, and drainable porosity of 11.8 % which is slightly over the ideal value of 10 %. This indicates that the A11 horizon has a large proportion of functional macropores that aid in infiltration, drainage and supply of oxygen for root function following wetting. The A12 horizon is slightly more compact at 1.47 g/cm³ and has lower drainable porosity at 7.6 %. Together the A11 and A12 horizons hold 25 % or 90.9 mm plant available soil water and 12.3 % or 44.3 mm readily available soil moisture The A2 horizons are compact and contain few macropores. In contrast to the A1 horizons the two A2 horizons (the A21 and A22) are extremely compact with an average bulk density of 1.80 g/cm³, an average drainable porosity of 4.8%, an average saturated hydraulic conductivity around 0.7 mm/hr, and contain only around half the readily available soil water at 5.2 % to 6.2 % as that of the two A1 horizons. The B2 horizon is unusual in that it effectively contains no large or medium sized pores and thus has effectively no drainable porosity at 0.8 % and only 3.4 % readily available soil moisture. Of the 96.3 mm soil moisture held in the B2 horizon 54.8 mm is unavailable for tree use.