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 structure of the topsoil (A11 horizon) appears to be in moderate condition. While the bulk density is quite low at 1.17 g/cm³ and thus does not appear overtly compact. However, the saturated hydraulic conductivity, a measure of macropore function, is low for a topsoil at 52 mm/ hr, and the drainable porosity, a measure of large macroporosity and the ability of the soil to supply oxygen to roots is low at 4.8 %, compared to the ideal value of 10 %. The A11 horizon contains 26.8 % or 67 mm plant available water (PAWC) which is large, of which 8.7 % or 21.9 mm is readily available for tree growth.

The A12 horizon is similar to the A11 horizon, except that the A12 horizon has over double the drainable porosity at 11.4 %, compared to the A11 horizon at 4.8 %. This provides further evidence of compaction and poorer than expected structure in the A11 horizon. The A12 horizon provides an ideal environment for root growth, soil water storage and soil water extraction. Unfortunately, the A12 horizon is relatively thin at only 100 mm and thus does not contribute greatly to overall soil moisture availability.

The B2 horizon is typical of many Ferrosols, half of the soil moisture is unavailable (24% of a total 46%), yet for a subsoil, it has reasonable drainable porosity at 3.7 % (the subsoils of many other soils are less than 2 %) and a low but still functional saturated hydraulic conductivity of 1.4 mm/hr and thus there is potential for slow air and water movement through the subsoil.