Rolling trials post-sowing to assist with a smoother seed bed, seed-to-soil contact and moisture retention.

Dry Sowing in South-West Victoria

Sowing conditions across South-West Victoria have proved challenging since the region recorded 80% below average rainfall in March this year, with local soil moisture probes reading 25-30% soil water content compared to 75% this time last year. Therefore, growers are forced to sow into drier soils than usual.

Dry sowing has often been avoided due to weed control concerns and establishment issues, however, there are several planning and management strategies to reduce the risks.

Benefits of sowing in dry conditions include longer vegetative stages where more light and water can be captured for growth.

Paddock selection plays a significant part in reducing the biggest risk to dry-sown crops, which are weeds germinating at the same time as the crop. Selecting paddocks with low weed pressures decreases reliance on pre-emergent and in-season herbicides, as knockdown herbicides will not as effective with the later timing of weed germination.

Canola can be dry sown into the previous year’s cereal paddocks with a non-resistance grass weed population to provide opportunities for post-emergent herbicide applications during the season. Similarly, faba beans and other legumes create opportunities for grass control in-season.

Timing your sowing schedule in dry conditions is critical to optimise crop performance, with the goal of reaching flowering within the optimal window in spring. An important note to remember is germination date is the crucial starting point for crop development when targeting the optimal flowering window, not sowing date. SFS research has shown that yield penalties were higher when sowing later than the optimal timeframe than sowing too early.

Machinery setup can be adjusted for dry sowing to maximise crop establishment. Slower sowing speeds can avoid soil throw and therefore pre-emergent herbicide damage in neighbouring furrows. Seed can also be sown slightly deeper than usual in dry soils to protect seed from lower moisture levels and avoid inconsistent germination. Seed-fertiliser separation is important to prevent fertiliser toxicity, particularly in dry soils where low moisture creates higher toxicity potential. Narrower row spacings and seed-fertiliser separation of 3-4cm reduces the risk of toxicity effects.

For more information and strategies for sowing in dry conditions, please refer to the GRDC’s guide Maximising Sowing Opportunities Under Dry Soil Conditions in the High-Rainfall Zone (2021).  

By Cameron Barr, Graduate Research & Extension Officer

Log in for full access to the SFS website. If you're not a member, you can find out more.