Phase 2

October 2nd, 2023

Prioritise and plan

Develop an amelioration strategy that matches machinery and amendments to the constraints present. Consider site preparation, timing and logistics, seedbed condition, strategies to minimise erosion risk and trafficability and herbicide management post amelioration.

Opportunities to treat sandy soil constraints to increase crop production can broadly be categorised as:

Mitigation approaches:

These are generally lower cost, annual strategies that aim to minimise the impact of a particular soil constraint on crop water use. Management tools include seeding and furrow design, soil openers, fertiliser form and placement, wetting agents and fungicides. These practices are expected to increase access to water in the soil but have little long-lasting impact on the soils inherent ability to hold more water.

Amelioration approaches:

These are higher intervention, higher cost strategies that aim to have greater, longer-lasting impact, through changing multiple properties of the soil profile. Management tools include strategic deep tillage, with or without the addition of clay, organic matter, or fertilisers of various forms. These practices can be expected to change both the amount of water a soil can hold (drained upper limit) and the amount the crop can extract (crop lower limit), thereby increasing the amount of water available to plants, lifting the yield potential.

Considerations when selecting a treatment option:

  • What combination of constraints need to be overcome? Which is the most severe?
  • What depths need to be targeted? Where do constraints start and stop?
  • Would the soil benefit from mixing/inclusion of topsoil or an amendment?
  • Is erosion a risk at the site?
  • How much are you willing to invest ($/ha) to treat constraints? 

The major constraints encountered on sandy soils in the Southern Region along with a summary of the different treatment options available are presented in Table 1. More detailed explanations of the treatments, and considerations pre and post implementation, are discussed below.