For Coonamble grower Tony Single, sorghum is a critical component of his cropping enterprise, increasing its sustainability and profitability.
The Singles have grown sorghum for 30 years. It allows them to increase cropping frequency while maintaining long fallows to harvest moisture more effectively.
However, well-above-average rainfall over the past 12 months has triggered an increase in sorghum hectares. This is to more effectively use full profiles and plant paddocks that were too wet for a winter crop.
Speaking at a GRDC Northern Update, Tony explained how he planned his crop sequences in relation to sorghum.
In April, budgeted gross margins estimated wheat would bring in $907/ha and sorghum $541/ha. This calculation included considering the time taken to grow these crops, ensuring a
like-for-like comparison.
We expect sorghum to yield about the same as wheat when sown on a full profile. Wheat is a higher-value product but to make a fair comparison you need to factor in when you can begin soil recharge time.
Tony also looked at agronomic considerations such as weed control options, rotations for disease management, soil type and stored soil water. He wanted at least 150mm to ensure a higher probability of achieving acceptable profit.
“So, at the beginning of the year, we were still planning on growing sorghum, but leaving just one paddock, and planning on more winter crops to make use of the water.”
Significant rainfall through the winter crop planting window changed those plans. Like many people on the east coast, it got too wet, and there were limited opportunities to plant.
“With full profiles, delaying until a 2023 winter plant doesn’t stack up, especially if you apply cost across the recharge period. Wheat 2023 will now have a budgeted gross margin of $567/ha while a 2022 sorghum plant could be worth $757/ha.”
For growers looking to plant a sorghum crop, Tony said, it was important to consider nutrition, particularly on full profiles. “Sorghum removes less nitrogen than wheat but is highly responsive to it.
Ideally, any application needs to be available at planting and for six weeks afterwards. This year, with very full profiles, there is a risk that denitrification will occur as things warm up. So perhaps consider splitting applications or drilling it.
However, he also suggested considering denitrification against lost yield potential. “It is also important to remember that capping top-end yield is potentially a bigger risk than denitrification. This year there is a balancing act.”
Timing-wise, he aimed to plant as early as possible in the window to avoid summer’s heat. “We have a narrow window and if we miss the late September/early October plant, we will wait and plant in mid-to-late December.” Three varieties were used to spread the risk – two short and one longer season – on one-metre row spacings on a single skip.