Ingenuity pushes mainstay crop limits
Queensland growers Wade and Sally Bidstrup have been pushing the boundaries of mainstay cropping with a novel approach to growing maize in a non-traditional area on the western Darling Downs. For the Bidstrups, this foray into maize cropping on the family’s 3000-hectare property at Warra, 45 kilometres north-west of Dalby, has meant developing a three-pronged strategy for managing seasonal risk. Wade says the strategy, built around variety choice, seeding density and sowing time, has positioned the crop so that it is able to get through the hot and sometimes dry conditions over summer.
In addition to reducing seasonal risk, the new approach, which involves early sowing of high-yielding maize varieties at low seeding rates, has also led the Bidstrups to rethink the crop’s place in their cropping program.
Wade estimates that the risk management strategy has significantly increased the overall productivity and profitability of their 250ha maize cropping area. As a consequence, it has become a dominant summer crop and a profitable cropping alternative to help shield their farm business from seasonal risk. Of the strategy’s core components, Wade says emphasis on selecting cultivars that produce more than one cob, so-called “multi-cobbing” varieties, has provided the largest yield gains.
For example, trials on the Bidstrups’ property have shown a four-tonnes-per-hectare yield difference between single-cobbing and multi-cobbing varieties in some years. Such high-yielding varieties include 31G66, 1467 and 607IT. Meanwhile, reduced seeding rates, which give each maize plant more room to develop extra cobs, have not only allowed the Bidstrups to lift their yields, but have also reduced their expenditure on crop seed by 30 per cent.
“Seed is the main expense in growing maize, so the saving on seed has made maize as cost competitive as sorghum as a mainstay summer crop,” Wade says.
He says maize commodity prices have returned at least $20t/ha more than sorghum in recent seasons, while halving their seeding rates has reduced their expenditure on maize seed from $150 to $88/ha. Wade says another benefit of the strategy, which involves sowing maize about a month earlier than in conventional growing areas – in the second week of August instead of late September or early October – is a major reduction in heat risk during the crop’s sensitive ‘tasselling’ growth stage.
Growing maize as a mainstay summer crop has further assisted the Bidstrups to vary their chemical modes of action, reducing the risk of herbicide resistance developing on their property. Establishing maize as a break crop has provided an overall decrease in pressure from diseases and pests across their cropping program, Wade says.
Region North, South