AgMemo Central Agricultural Region

Are you sowing the right plant density to maximise profit in your malt barley?

Biomass differences at 10 weeks after sowing of barley sown at four target densities: L to R 100, 50, 400 and 200 plants/m2

Research by Department of Agriculture and Food Western Australia (DAFWA) in partnership with the Grains Research Development Corporation (GRDC) has shown that the optimum plant density for growing malt or food barley is either 120 or 150 plants per square metre.

Based on the outcome of 33 barley agronomy trials (2012-2014) the following recommendations are made:

• Optimal profitability for Baudin, Commander, Granger and Scope CL is achieved at a target plant density of 120 plants/m². Sowing less or more than this density can result in a $20-25 per hectare penalty.
• Profit in Bass, Flinders, Hindmarsh and La Trobe is less sensitive to increasing seeding rate. The suggested target plant density for those varieties is 150 plants/m². It isn’t until plant densities exceed 200 plants/m² that profit starts to decrease in those varieties.
• The recommendation for feed barley varieties is to sow at least 180 plants/m² with higher densities improving barley’s competiveness against weeds.

The target seeding rate in kilograms required per hectare will differ between varieties due to differences in their seed weight.

It is important for growers to determine their 1000 seed weight so they can accurately calculate the kg/ha seed rate required to achieve the optimal plant density.

It is simply a matter of counting out 1000 seeds (say 50 lots of 20 seeds or 10 lots of 100 seeds) and then weighing them on your kitchen or spray scales.

Use the 1000 seed weight (in grams) to calculate the seed rate in kg/ha to achieve a density of 120 or 150 or 180 plants/m².

The calculation and target density for each malt and food variety can be found by referring to optimal plant density for barley webpage.

Once you have the seed rate in kg/ha you can calibrate your seeder and you are then ready to go seeding.

Target plant density in plants/m2 for sowing barley

These recommendations suit environments with a yield potential above 1.5 t/ha and do not change if the time of sowing is delayed three to four weeks (ie. mid May to early June) or if the site potential is 2, 4 or 6 t/ha.

For more information contact Blakely Paynter, Senior Research Officer, Northam  on +61 (0)8 9690 2115 or +61 (0)427 988 098.