SOIL HEALTH THE KEY TO REDUCED FERTILISER RATES
CHRIS O’KANE ON CHANGES TO FARM PRACTICES
30 MARCH 2021
When it comes to soil, the O’Kane brothers like theirs as soft and crumbly as cottage cheese.
It’s a strictly gorgonzola-free zone at Chris and Michael’s sugarcane farm where four years of new practices – from mixed species fallow crops to biofertiliser, minimum tillage and mound planting – are changing the soil’s structure and its crop-growing potential.
Cheese references have become technical terms these days for an ever-increasing number of farmers who are just as focused on what’s happening underneath the earth as what’s growing up above it.
The O’Kanes have reduced their artificial fertiliser rates by more than 30 per cent as a result – dropping from 156kg to 108kg of nitrogen per hectare with minimal impacts on their crops or production levels.
“We’ve done our homework – we’re not scared of trying new things but we don’t rush in either,’’ Chris said. “If we believe something’s going to work, we’re up for giving it a go.”
The third-generation cane farmers are embarking on another big change this season, forming mound rows for fallow crops that will become long-term cane rows. It’s all about reducing soil compaction.
“Traditionally at planting time we would cultivate the whole paddock by discing, ripping and rotary-hoeing,’’ Chris said.
“This year we will be moving to zonal cultivation using one implement, a bed renovator, to prepare the bed only where the cane set is to go.
“With the help and guidance of farmers in the Ingham district we are modifying our billet planter into a mound planter. So once planted, the paddock is finished as far as cultivating. There is no more filling in to get the right ground profile for the harvester.”
Chris said learning from growers in other districts had removed any concerns about potential issues like reduced cane strike rates, stool tippage and loss in production.
Learning from others about biofertilisers has also helped.
“Once you’ve been shown, it’s pretty easy to catch on – we’ve been brewing for four years now,’’ he said. “We apply bioferts to each paddock twice a year, spraying nine rows at a time with a mixture of effective micro-organisms and trace elements. It’s a recipe we were given. We need 20,000 litres for the farm – it takes about three days to make 10,000 litres but the beauty of it is it stores well so it can be made when there is time.”
The O’Kanes were among 39 Wet Tropics growers to take advantage of the Australian Government’s Reef Trust IV tender program, delivered through natural resource management organisation Terrain NRM. The program is helping to finance changes reducing fertiliser use on these farms, and potentially on other farms in the future.
Chris says he and Michael are also fine-tuning their fallow crops.
“Dad always planted bean varieties but that usually consisted of one type of legume,’’ he said. “We’ve moved to a mixture of soya bean, cow pea, lab lab, sunflower and this year also sun hemp.
“We’re aiming to increase our organic matter and improve our soil structure more than anything. We saw the results almost straight away with soil structure – the soil crumbles in your hand – and we’re noticing that maybe ratoons are lasting longer so we’ll keep watching that to see if it’s related.
“If there’s one message that’s ringing true, it’s that diversity above the ground gives you diversity under the ground. That’s what we’re aiming for. Some of our soil types don’t allow us to apply phosphorus so by using sunflowers for instance, it unlocks the phosphorus and makes it available for other plants.
“Hopefully, at the end of the day we’re reducing our inputs even further, saving time and money and leaving the land in a better condition.”