Managing eroded soils

Key points

• Losing just one millimetre of topsoil equates to 12 tonnes per hectare and can result in yield losses of between one and six per cent.
• Long-term soil nutrient management is important as many critical nutrients need to be replaced as fertiliser.
• Soil testing can help determine phosphorus and nitrogen budgets for eroded soils.
• Re-evaluation of production zones prior to soil testing is important as erosion may have changed nutrient distribution, resulting in new high and low production zones.
• It is recommended that at least 20 per cent of the farm is soil tested each year, to allow for comparable results year-on-year.
• Cover crops or stubble retention provides soil coverage without disturbing the top layer of soil.

Dry conditions coupled with severe wind events during 2018 and 2019 caused significant erosion within some southern region cropping paddocks.

Erosion can cause a range of effects, from large dust storms which move soil particles hundreds of kilometres, to small wind events which only move finer fractions of soil a few metres across the paddock surface.

During erosion, the topsoil of paddocks settles in places where the wind slows, such as around fencelines and trees, while the finer fractions can continue moving, resulting in uneven paddocks.

Wind erosion occurs when there are wind speeds strong enough to dislodge the soil particles on a susceptible soil surface, such as areas with little ground cover.

The removal of valuable topsoil rich in key soil nutrients and organic matter is detrimental to soil and crop performance.

Losing just one millimetre of topsoil is the equivalent to losing up to 12 tonnes of soil per hectare and can result in a one to six per cent yield loss.