Managing land according to soil capability
MLA & AWI July 22, 2024
Doing the right thing in the right place at the right time means knowing where different soil types are and how to manage them appropriately. For example, whether or not to fertilise, and if so, how much and when. Managing soil according to its capability aims to make the best possible use of the soil resource by targeting areas that give the best return for effort, time and money by maximising nutrient and water use.
For example, fertiliser will give the greatest economic return when it is:
- applied to paddocks with the most responsive pasture species (e.g. introduced, desirable grass and legumes rather than native species)
- utilised effectively — there’s no point growing more pasture if it isn’t utilised
- managed using a responsive grazing management system, such as rotational grazing, which maximises growth and response through pasture recovery periods.
The first step in managing according to soil capability is to identify the different soil types, or land classes, across a property. Factors that influence soil capability include soil type, depth, slope, fertility, identified problems, current use and productive potential. Knowing where different soil types are enables better management and decision making. The Guide to classifying land capability tool offers detailed information on land classes.
Soil type and land class can influence:
- whether or not to fertilise (if so, how much and when)
- where and how to sow improved pasture species or plant crops
- how to graze (e.g., crash grazing, rotational or set stocking).
In addition to managing to soil capability and land class, it is also important to manage riparian zones, biodiversity, tree planting and ground cover levels and identify any difficult-to-manage areas, such as steep hill country, drainage lines, areas prone to waterlogging, shallow soils and areas where salinity, acidity or sodic dispersive soils may be a problem.
The most practical way of bringing all this soil and paddock information together is to construct a farm map, which can be digital or hard copy.
Creating a farm map
A farm map builds a picture of soil types and natural assets that require different management to maximise their protection and production. It shows existing farm features and different overlays of information, such as land classes, which are areas that require different management because of their soil capability.
Ideally the mapping exercise will provide a picture of the current productivity and potential for each paddock or land class, enabling an assessment of the possibilities and limitations each area poses for a farm business. Most critically, a farm map allows the current or anticipated land use to be matched to land capability on a paddock-by-paddock basis.
Farm maps can be supplemented with satellite images. Google Earth Pro is available for free and contains drawing and measuring features. These can add additional insights into farm planning and align production goals with farm capability and productive potential.