Climate driving change
GroundCover™ Issue: 96 | 06 Jan 2012
- By Sarah Cole
Duaringa is a small town about 100 kilometres west of Rockhampton, Queensland. It is well resourced by three rivers – the Dawson, Mackenzie and Fitzroy.
Like much of the country in central Queensland, Duaringa suffers from droughts and floods, and experiences summer temperatures as high as 45°C.
Colin Dunne says he has witnessed a lot of climate variability on his Duaringa property in the past 50 years.
“In the 1950s we got well over 1000 millimetres of rainfall a year. In 2009 we had 20mm over six months and in 2011 we’ve had a big flood,” he says.
“Ever since I can remember, we’ve had a variable climate. The overall average of the extremes hasn’t changed much, but the minimum temperatures for [nearby town] Emerald appear to be getting significantly warmer.”
Data from the Bureau of Meteorology shows that the monthly mean minimum temperature at Rockhampton Airport (89 kilometres from Duaringa) has increased from 8°C to 10°C since reliable measurements began there in 1940.
Therefore, the way in which he responds to seasonal conditions is central to Colin’s business management.
Because Colin can plant any month of the year, he grows crops year-round. These include sorghum, corn, mungbeans, chickpeas and wheat. His main spring and summer crops are mungbeans, corn and sorghum; in winter, it is chickpeas and wheat.
The main climate-related decisions he makes are to do with row-spacing, rotations and double-cropping; and in his cattle operation, weaning times, feeding breeders and stocking rates.
Trials suggest that 1.5-metre-wide rows give significant yield benefits over rows that are only one metre wide in a dry year, says Colin – and that is what he does in marginal years.
Wider row-spacing is central to Colin’s moisture management in his summer crops. During grain-filling time, the crops will spread their roots sideways looking for water, especially sorghum.
“If I had planted another row of sorghum in the wide space in the middle, the crop would have used all the water up earlier. But with wide rows, at the time of grain-fill and flowering, the crops still have a reservoir of water left in the middle.”
Colin’s cropping rotations primarily depend on climate outlooks and rain events.
“I plant depending on the seasonal conditions at the time. Ideally, I rotate legumes around all of our country. In spring it’s very good to plant mungbeans because you can harvest them before the wet and still plant another crop. Chickpeas are a lot slower,” Colin says.
The final crop management strategy Colin uses is double-cropping – that is, producing two crops on the same land within the same year or three years, one after the other – and opportunity cropping.
“I have harvested crops and double-planted a second crop following that to try to use an opportunity crop. If it rains, we get a good crop; but if I don’t get a second crop, (it means) I was pushing it to the limit.”
But he says it is not all “doom and gloom” if an opportunity crop does not go as planned. A crop that does not do quite as well, still provides useful ground cover for holding soil moisture for the next crop if there is rain.
Adjusting to climate
Colin is used to the extremes that Duaringa experiences in summer and winter, including frosts and flooding.
But what he has noticed is that the number of frosts in the region is declining as minimum temperatures rise. For Colin, it actually means he can start planting earlier.
Colin now plants chickpeas on about 25 April. “Chickpeas can come back after a frost if there’s moisture in the ground, but wheat won’t.” Frosts are of more concern for Colin’s low-lying cattle country.
Another extreme that farmers on the Mackenzie River see is flooding. The river flats comprise very heavy soil and very deep soil to at least 10 metres.
“Every 10 years, we get between one and four metres of water over our farming (cropping) country. My cattle country is a bit lower. It probably gets six to eight metres of water when that happens,” Colin says.
While floods can prevent summer cropping, Colin says he had a win in early 2011 by sowing chickpeas into the wettest country. These did well compared with the wheat he sowed because of zinc and nitrogen deficiencies, which are an after-effect of flooding. “Next time, I’ll put in more chickpeas rather than wheat.”
Colin is eager for more seasonal climate information. “Knowing what’s going to happen in the next couple of months would be very beneficial.”
As forecasts from the Bureau of Meteorology improve with time, he hopes to be able to decide earlier which crops to sow, or whether to harvest earlier to avoid rain on the grain.
Colin has used the Bureau of Meteorology’s Climate Data Online (www.bom.gov.au/climate/data) to research temperature and rainfall trends for his and surrounding areas. Average minimum temperatures, he says, appear to be rising over the time of the records he has looked at. He wants to keep an eye on these trends.
Colin believes it is important to be able to use and make sense of figures and trends in the local area – “for the average farmer like me” – and sharing it with other farmers.
“I’d like to go back through the climate history to have a look and see what those trends are so we’re in a better position to deal with them. But I’m sure 99 per cent of farmers are working towards that anyway.
“I think in the past 12 months farmers out here feel that forecasting is getting better,” he says. “The important thing is having the outlook and data if you need to use it to deal with the variations that come.”
Colin is a participant in the Climate Champion program.
Grower: Colin Dunne
Region: Duaringa, central Queensland
Commodities: Sorghum, corn, mungbeans, chickpeas, wheat, organic beef cattle
Farming area: 2200 hectares for cropping, 9800ha for grazing; six other certified organic grazing/fattening cattle properties total 52,000ha
Rainfall: 250 to 1500mm per year
The GRDC’s Climate Champions is a program providing early access to research assessing the impact of climate variability in different agricultural regions and to help growers adapt their production systems. Participants have been selected for their willingness to learn more about the influences of climate variability and to provide leadership to other farmers by sharing their experiences and what they have learnt.
IMAGE CAPTION: Colin Dunne places a strong emphasis on soil moisture management in responding to climate variability.
GRDC Research Code ECO0003
GRDC Project Code ECO0003
Region North, National, South, West
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