Agricultural
13 September, 2022
Sorghum Cropping Opportunities
Growers eager to capitalise on summer cropping opportunities this season should be testing soil temperatures now to determine whether they can take advantage of early sowing opportunities.
The summer cropping area is expected to increase this year, with many growers missing out on planting their full winter cropping area or losing young crops to waterlogging due to ongoing wet conditions over the past few months.
The Grains Research and Development Corporation (GRDC) has invested in extensive research to improve the agronomic guidelines of summer cropping in the north and has developed ways to mitigate the high risk of heat and moisture stress during flowering.
Through numerous trials conducted by the University of Queensland, NSW Department of Primary Industries (NSW DPI) and Queensland Department of Agriculture and Fisheries, research has indicated the most effective way to avoid heat stress during flowering for summer crops, particularly sorghum, is to shift sowing windows to earlier in the season.
NSW DPI Research Agronomist, Loretta Serafin said traditionally, optimal soil temperatures for sorghum planting have been between 16 to 18 degrees.
“The downside to that has been that growers have been unable to avoid their crops flowering at peak temperatures during summer - causing significant yield loss from moisture and heat stress,” she said.
“Our research, through extensive trials, has shown there are opportunities to plant sorghum when the soil’s as cold as 12 degrees as long as temperatures are rising for the following seven days.
“When testing the soil temperature, it’s advised growers wait to plant until their soil is recording 12 degrees at a minimum (tested at 8am) at intended seeding depth,” she said.
“Growers should also be looking at the seven day forecast for the rest of the week to help determine whether temperatures will continue to rise which is highly desirable.”
“There’s also an opportunity for growers to look at planting sorghum earlier and having the crop harvested prior to winter sowing. Having the sorghum harvested earlier would give the soil profile time to fill again prior to winter sowing and growers would potentially be able to double crop the paddock into chickpeas.”
Ms Serafin said while an earlier summer planting window definitely gives growers an opportunity to balance risk, it doesn’t mitigate the potential for heat stress entirely.
“The important thing to note is you can never totally eliminate the risk of heat stress in summer crops - in some cases, growers will still hit a hot period when the crop is flowering despite planting earlier but it helps to balance the risk.”
“Some growers will opt to plant some of their crops earlier and some in the traditional window, which will help split the risk across the season.
“The point of this research is to give growers options with their summer cropping decisions and what best suits their farming operations.”
Ms Serafin said growers looking to plant sorghum early need to consider weed management as a priority, as it’s harder to manage winter weeds in a summer cropping situation.
