THERE was an old saying in cropping circles that break crops were so named because they could send farmers broke, but studies have proven the opposite is true.
Mallee Sustainable Farming agronomist Michael Moodie outlined the results of research into break crops at the GRDC Grains Research Update held at Wudinna.
MSF, along with the Eyre Peninsula Research Foundation, Upper North Farming Systems group, Birchip Cropping Group in Vic and the Central West Farming Systems group in NSW, have been involved in the GRDC’s low rainfall crop sequencing project. The project started in 2011 with field trials at sites across the low rainfall zone in south eastern Australia.
“On the EP there was a series of good years, but in Mildura, Vic, we had a series of poor years, where growing season rainfall was less than 140 millimetres,” Mr Moodie said.
“Having that spread of different seasonal conditions in the trial gives us confidence in the results.”
At the time, paddock rotations in the low rainfall region were dominated by intensive cereal cropping and broadleaf grain crops accounted for less than five per cent of the area sown.
But, this reliance on cereals was causing serious issues with productivity, particularly due to grass weeds, declining soil nitrogen and crop diseases.
“What we found with this work is that you can produce really big benefits to the following wheat crops, similar to what you find in the high rainfall zones, with a potential one tonne a hectare to 2t/ha yield increase, compared to sticking with a continuous wheat system,” he said.
Break crops had the potential to increase the overall profitability of cropping rotations.
“It can add up to $100/ha a year in the low rainfall zone,” Mr Moodie said.
But, Mr Moodie said it was important to choose carefully when looking at break crops, as they needed to stand up on their own in terms of profitability, as well as addressing agronomic issues.
“There is no overall best rotation, you need to choose a break crop that addresses the constraints you’re having,” he said.
“If you have a well-managed stock system, medics can deliver some benefits.
“In the Mallee, legume crops have been quite profitable in the last few years. Field peas and chickpeas have shown a lot of promise in the Mallee.
“But, overall, there appeared to be little impact from the choice of break crop, as long as it addressed the agronomic constraints present in the paddock.”