Precision ag drives WUE with yields the end goal
GroundCover™ Issue: 109 | Author: Rebecca Jennings
Mark says that improving the productivity of his existing area has become essential as expansion is ruled out due to escalating land prices. Since 2000, land at Giles Corner has jumped from $3100/ha to $12,000/ha. Added to this constraint are the highly variable soils.
“Our soils are productive but their mosaic nature means significant differences across the farm in yield potential,” he explains. “This is where precision agriculture (PA) is so valuable, allowing us to target production potential to soil types.” Since taking on the farm’s management in 1990, Mark has set his sights on improving soil health, soil structure and WUE. He regards WUE as the most accurate measurement of crop performance across highly variable seasons.
The Bransons have a tradition of innovation. They introduced grain legumes into their rotation and adopted minimum tillage in the 1980s, started yield mapping in 1997 and moved to no-till in 2002. “We introduced controlled traffic with real-time kinematic two-centimetre GPS in 2004, and all major farm machinery – including our Case IH 7120 header and John Deere 8200 tractor – has auto-steer.”
The Bransons’ sowing equipment is set on 9.8-metre spacing, and their self-propelled sprayer is 39.2m to reduce passes. After a fire in 1996 destroyed 25 kilometres of fences, Mark redesigned the farm to optimise PA by realigning paddocks to land class and for easier passes. In 2005, armed with a Nuffield Scholarship, Mark spent 18 weeks studying farming systems in the US, Canada, the UK and Europe. He came home full of ideas and developed a full PA fertiliser program with all phosphorus-based fertilisers applied at variable rates.
Variable-rated monoammonium phosphate down the tube at sowing (the average rate is 70kg/ha) is the only nitrogen Mark now applies up-front. He then uses a handheld GreenSeeker® to monitor input requirements and CropSpec sensors to support variable-rate nitrogen application.
Add high carbon break crops, manuring and high stubble loads, and the Bransons’ strategy is paying off. From 1988 to 2005, they improved the WUE of wheat by 1.1 per cent a year but this has jumped to 2.1 per cent a year in the past decade thanks to new technology. “On a five-year rolling average, our WUE has increased from 63 per cent in 1988–92 to 98 per cent in 2008–13. Ten years ago I would not have considered this possible.”
GRDC Project Code UA0032, UA00126
Region National, South, North, West