The Department of Primary Industries and Regional Development (DPIRD) has been working with the West Midlands Group (WMG) and producers to investigate widespread areas of sandy soils with low groundcover at risk of soil erosion.
DPIRD research scientist Geoff Moore said the widespread occurrence was unexpected, given the favourable growing conditions in 2021.
“We have been looking at an area from Gingin, north to Allanooka near Geraldton, and west of the Darling Fault line to investigate the causes and develop a path forward,” Mr Moore said.
“A common denominator across all the sites investigated was high grasshopper numbers during last year’s growing season, along with other contributing factors like a false break, over-grazing or a low pasture seed bank which tended to be site specific.
“A number of producers were proactive in spraying for grasshoppers and/or over-sowing pasture paddocks – sometimes with whatever seed they had on hand.
“We are working with the WMG and some leading producers to share their experiences about what remediation worked well and what was less successful.”
Mr Moore said early autumn rainfall this season had resulted in germination of annual pastures and the warm conditions had supported good growth of sub-tropical grass pastures.
“Some of the previously-affected paddocks now have good seedling numbers and a good pasture seed bank, which should result in adequate groundcover this year given good grazing practices,” he said.
“However, for some paddocks or areas within paddocks which have low seedling numbers, this is likely a sign of a low pasture seed bank.
“For these areas, supplementary over-sowing of a cereal-pasture mix is recommended.
“We encourage producers to be proactive and have a plan in place to prevent wind erosion and maximise soil productivity for the 2022 season.
“Producers also need to have a ‘plan B’ in place, in case there is a major false break and monitor regularly for grasshoppers.”
DPIRD entomologist Svetlana Micic said the wet summer going into the 2021 season had provided the sand grasshopper with ideal conditions to breed and their feeding damage decreased pasture productivity.
“We have recently received reports of grasshopper hatchings, so we are encouraging growers to monitor and control grasshoppers if pastures are not out-growing damage,” Ms Micic said.
More information on seasonal issues, including land and water management, can be found on DPIRD’s Season 2022 webpage at agric.wa.gov.au
Information on identification and control of sand grasshopper is also available at the DPIRD website.
Photo caption: Farm manager Don Bradshaw (far right), Badgingarra, with DPIRD officer Nazanin Nazeri, West Midland Group project officers Melanie Dixon and Erin O’Brien, in a perennial grass paddock with excellent groundcover despite the dry seasonal conditions. Pictured in March 2021, before autumn rain.
