Soil Management

Despite showing signs of compaction or loss of surface soil structure, this soil has good water retention properties, and good drainable porosity within the three A horizons. Organic carbon content of 2.11 % and a hydraulic conductivity of only 65 mm/hr in the topsoil suggest that soil health and function could be improved through increased application of plant residues, grass clippings, manures and composts. Aluminium toxicity in the B21 horizon and presumably B22 horizon indicates the subsoil is hostile to root growth and function. Consequently, soil water extraction is likely to be limited to the three A horizons with contain 97 mm plant available soil water and 40.9 mm readily available soil water to a depth of 45 cm. This indicates that irrigation should be moderately easily able to maintain moisture and avoiding moisture stress. In relation to irrigation, the refill point for the A1 horizon is between 27 % (50 kPa) to 22 % (100 kPa) soil moisture. The nutrient retention capacity of the soil is low such that small and often application of fertilizer will be required to minimise risk of nutrients leaching below the root zone, or leaching laterally down slope within the A2 horizon. Mottling patterns in the B horizons indicate these soils are prone to seasonal waterlogging. The low ESP in the B21 horizon indicates these soils may be suitable for mole or subsurface drainage. Further investigations are required to determine sodicity levels further down the soil profile.

Note

The mountain river site was investigated for the purposes of understanding the effects of biochar on nutrient leaching in which physical characterisation was conducted of all soil layers, chemical analysis and profile description were minimised for the purpose of soil classification rather than full site description. 

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