Understanding the Influence of Row Spacing and Direction in the Mallee

A recent two-year trial has produced encouraging data to help Mallee farmers understand the role that row spacing and orientation play in crop performance and weed control. 

With insight from trials undertaken in Western Australia and New South Wales, Birchip Cropping Group has recently completed a project to investigate the influence of row spacing and orientation to manage weeds.

The trial aimed to determine whether sowing direction and row spacing could be used to reduce grass weed pressure and what impact they have upon crop performance, specifically in Mallee growing conditions.

In 2015, a trial plot was established in a farmer’s paddock at Jil Jil, 23kms north of Birchip. Tame oats were broadcast as a weed treatment before seeding and established at 42 plants/m². Mace wheat was sown on the 23rd
May using knifepoints and press wheels at 22.5cm (9 inch), 30.5 (12 inch) and 38cm (15 inch) row spacing, with a target plant density of 150 plants/m². In addition to the different row spacing, the trial plot included rows sown in a northsouth and east-west direction.

Encouraging early season rainfall events resulted in good crop and weed establishment across the trial site. However, the season ended as a decile one, with much of the wheat failing to tiller and low overall yields. Between 30% and 50% of the oats died, with the remaining oats being short with only one or two panicles.

The trial was monitored with incrop assessments including crop and weed counts throughout the growing season, as well as grain yield and quality testing after harvest.