Soil survey

Reconnaissance soil survey – a free survey approach with soil profile description sites based on general landform features and geological information provides an indication of the soil variability over a greenfield development site for irrigated horticultural production.  Identification of general soil limitations and amelioration requirements are discussed in the soil report.

Detailed soil survey – a grid soil survey over the proposed development site is used to more precisely map soil type and landform boundaries.  The soil types are accurately mapped and their limitations determined based on soil profile description and soil chemical analysis of soil samples from selected sites.  The potential crop rootzone depth is determined from soil profile description and the readily available waterholding capacity (RAW) at each site is calculated. The RAW value is used for irrigation design, variety selection and irrigation block layout.

Readily available waterholding capacity (RAW) represents the amount of water held within the soil between field capacity (-10 kPa) and the specified matric potential (or suction) at which plants may suffer stress. The results are in millimetres (mm). For vines and olives the lower limit of suction is -60 kPa (kilopascals), for vegetables it is -20 kPa and for native vegetation it is -200 kPa.

Determination of soil amelioration requirements prior to planting.  This may include: where to apply agricultural lime or gypsum; where to apply fertiliser or improve organic matter content of the soils; which areas may require drainage and or protection from erosion risks such as wind and water.

ArcGIS generated maps are produced to show the soil type and soil management zones.  The descriptive soil maps aim to convey the soil data in a meaningful way that is easily interpreted.

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Soil survey – for irrigated agriculture, broadacre farming and land resource mapping

Land capability mapping – determining the limitations of the soil and land for general agricultural use. This mapping considers the slope, flooding, drainage and erosion risk of general agricultural practices.  For example: class 1 land would have few limitations for agriculture; class 5 would have extreme limitations and is considered non-arable.

Land suitability mapping – determining specific crop or land management limitations for irrigated and non-irrigated developments.  This mapping applies specific limits for soils, topography and drainage within each land class for the proposed land use.  The maps produced will identify different land management units and the agricultural practices within each land unit.

Soil landscape mapping – the major geological differences in a catchment of regional area are identified and mapped from known data and ground truthing.  The landform pattern within these geological zones is then described using measuring of relief and slope.  Finally the soil variability within each of the geological and landform pattern zones is described from a series of soil profile observations.