Preventing erosion

Looking after soil structure can prevent erosion

As we move into summer, the weather is finally warming and spring-sown crops such as onions and pyrethrum are beginning to emerge.

These two crops require a particularly fine and well-prepared seedbed to allow adequate seed-to-soil contact for their small seeds to germinate and establish. Therefore, good paddock preparation to manage soil structure is essential.

Good soil structure below the seedbed is also important to consider, to allow rainfall and irrigation water to infiltrate down into the soil profile.

Achieving this will reduce the risk of surface runoff eroding the well-prepared seedbed until the crop is sufficiently established to bind the topsoil together itself.

Cultivation alone is unlikely to prevent soil erosion if the soil structure below the seedbed is less than optimal, even if physical erosion management techniques, such as rip lines across slope contours of the paddock, are utilised.

There are options to consider which can be used several months before planting to better prepare paddocks for fine-seeded and slowestablishing crops sown in spring. Using a simple cover crop will result in root growth improving soil structure and water infiltration, as well as increasing nutrient cycling and supporting microbial populations.

An added benefit is that the cover crop used in this case would protect the soil from winter rainfall events, further reducing the risk of erosion in the preceding season to sowing your cash crop.

When using a cover crop between cash crops, it is important to clearly identify a sowing and termination date, so that aboveground plant biomass doesn’t get out of control and become a problem to manage.

Above-ground plant biomass height of 15-20 cm is sufficient to protect the soil, as well as being manageable to terminate without creating issues with unwanted moisture.

Cradle Coast Authority, through funding from the Australian Government’s National Landcare Program, is trialling simple cover crop blends which can be used to condition and protect our productive soils between vegetable and other cash crops.

For more information contact coordinator Ali Dugand adugand@cradlecoast.com project at