Soil Management

The plant available water content at 173 mm, and readily available soil moisture at 57 mm are substantial. This should be a relatively easy soil to irrigate without causing moisture stress. In relation to irrigation, the refill point for the A1 horizon is between 40 % (50 kPa) to 36 % (100 kPa) soil moisture. The low CEC and high levels of potassium and phosphorus in the A11 and A12 horizons indicates potential for leaching of nutrients below the tree root zone, and ultimately to shallow groundwater. Regular leaf analysis is recommended before additional application of phosphorous and potassium at the site. It is recommended that application of lime be discussed with your local agronomist to increase pH, increase available calcium, and potentially increase availability of phosphorous. The A11 and A12 have very high organic carbon contents for an orchard. Despite the very high carbon content there is some evidence of soil structure decline and compaction in the A11 horizon. This appears to have mostly affected the saturated hydraulic conductivity which measures infiltration and drainage, and the drainable porosity which measures the amount of air space in the soil after the soil has drained.  The consequence of this reduced soil structure is slower infiltration and drainage and prolonged wetness and low oxygen status following rainfall and irrigation. It is recommended that management maintain current practice of residue retention and efforts to increase soil carbon, and wherever possible minimize vehicle traffic on or near the tree row. 

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