NUFFIELD scholar David Cook has turned his property into a gigantic trial site to determine the profitability of continuous cropping programs.
David and wife Tracy, together with his parents, Neville and Wendy Cook, run an amalgamation of family and share-farmed properties outside Shepparton, Victoria.
This season, the 800 hectare property was sown to a mix of wheat, canola and faba beans, with about 10 per cent of this sown into cover crop strips sown in mid-January.
He is investigating the benefits of cover crops in boosting organic carbon levels in the soil, something he believes is limited in current no-till systems and crop rotations.
He is also conducting a series of replicated trials examining a novel nitrogen application method, increased pod set in faba beans and various crop protection programs.
“I am focused on changing my approach to building soil health that, in turn, will drive plant health and possibly reduce our reliance on crop protection products,” he said.
“The big picture is trying to increase our long-term average gross margins rather than maximise our margins in the good years.
“Nobody has the information that I want so there’s only one way to find out. We’ve got all this variable application rate technology and yield data at our fingertips, so we might as well use it.”
Mr Cook admits that pushing the boundaries of conventional thinking involves risk.
“We honestly don’t know what the outcome is going to be,” he says.
“If something doesn’t work, we might lose 10 per cent of our yield but the ultimate goal is to reduce our long-term risk through improved knowledge.”
The current enterprise is a far cry from when Mr Cook returned to the farm. The family used to run a mixed farming enterprise with about two thirds pasture and one third cropping and some irrigation.
The amount of cropping was gradually increased to about two-thirds, and they took on the share farming and expanded the irrigation to 160 hectares but “we lost all of our irrigation – which accounted for about 20 per cent of our arable land – when Lake Mokoan was decommissioned in 2007".
“Our attitude was that if we were back to 100 per cent dryland cropping, then we had to do it properly. We decided to get rid of the sheep and concentrate purely on cropping,” he said.
They also moved from minimum till and burning stubble into a controlled traffic, zero-till program with full stubble retention.
Purchase of a ultra-low disturbance New Zealand built Cross Slot seeder in 2008 - a hybrid between a disc and a tyne seeder with a coulter sitting between two opposing blades that form an inverted Baker ‘T boot’, combined with a wet autumn in 2011 and 2012 opened up summer cropping options.
“We had stubble on the ground and moisture in the soil, so we thought there was no reason why we shouldn’t opportunistically put in a summer crop,” Mr Cook said.
He reckons southern farmers, particularly those in higher rainfall areas, need to shake the once-a-year sowing mentality and follow the moisture like northern farmers do.
“If there is enough moisture to grow fallow weeds, then there is enough to grow a cover crop that benefits the soil.”
He has sown a range of dryland summer crops, including sorghum, safflower and millet, in five of the past six years, resulting in four profitable harvests.
The highlight was in 2010/11 and 2011/12, when a number of paddocks were double-cropped to shirohie millet and then wheat, achieving an annual gross margin of more than $1500/ha in both years.
Cover crops have included mixes of millet, sunflowers, corn, sorghum, winter wheat, winter canola, faba beans, soybeans and cowpeas.
“In some years, we have got straight off the harvester and started sowing if it’s rained,” Mr Cook said.
“The goal is to get as much vegetative growth in 12 months of the year, rather than just seven months.
“We are trying to add organic carbon to the soil to build up and maintain an active soil microflora 12 months of the year.”
Direct route to efficient harvesting
On the machinery front the opportunistic purchase of a Claas Lexion 750 harvester with a 10.5 metre VARIO variable cutterbar in 2012 proved an important milestone.
The cutterbar technology allows the distance between the knife bar and the intake auger to be adjusted by up to 300 mm "on the go" to suit different crops and harvesting conditions.
Adding filler plates to the cutterbar extend it by 500 mm and allow direct heading of canola.
“We’d just purchased a second-hand Miller Nitro 4275 self-propelled sprayer and our intention was to fit a draper front to windrow our canola and spray under the windrows at the same time for weed control, especially any resistant rye grass,” he said.
“Then I went on a study tour to Europe, and nearly all the places we visited were using Lexion to direct head canola, which made me start to reassess this plan.
“I got back and spoke with some other Lexion owners and decided direct heading was the way to go.
“Direct heading means the windrowing is replaced with a dessciation spray, which is a quicker and cheaper operation."
In 2013, David was awarded a Nuffield Scholarship, supported by The William Buckland Foundation, to study the relationships between crop rotations, nutrient availability and fertiliser programs in different farming programs throughout the world.
More recently, he has begun experimenting with "controlled uptake long-term ammonium nutrition" (CULTAN), which aims to supply the crop’s entire nitrogen requirements as a single soil injection.
His home-made test rig pumps a blend of liquid sulphate of ammonia and UAN from a 1000 litre shuttle to three spiked wheels, which inject the nitrogen to a depth of 75 mm at 15 cm intervals in every second crop row.
He credits his parents for giving him the opportunity to try his hand at something different.
“My grandfather had the foresight to hand over the management of the farm to my father at an early age, and Dad has done the same for me,” he says.