A wide range of techniques and data sources is used to conduct a soil survey. Usually, a soil survey comprises an initial desktop review of available information, followed by field observations, and finally computer-based delineation of soil survey units and map delivery. Predicting or ‘modelling’ can also play a role, especially when trying to cover larger survey areas.
The desktop study checks on relevant historic soils information, as well as associated environmental factor maps that describe the geology, climate, topography, and land use, that all interact to form soil.
The field survey is conducted using hand-held augers allowing soil descriptions to a maximum depth of 1m. Common soil properties captured from an auger are soil horizons, texture, structure, colour and soil type. Soil pits can be used for more detailed characterisation of ‘typical’ soil properties. Soil sampling is a standard part of any soil survey; laboratory analyses allow insights into chemical and physical properties which cannot be easily observed in the field. They also help to confirm the preliminary soil classification made while in the field.
Bringing environmental factor data, auger point and/or soil pit information and lab analyses together will allow the soil scientist to identify areas in the landscape where soil formation processes – and thus soil characteristics – are similar. These areas of similarity define the map units. By combining all the different map units, a soil map is created.
Today, modern Geographic Information Systems (GIS) and geostatistical methods improve our ability to detect relationships between soils and the other environmental factors in the landscape. This contributes to better soil maps.
