Variable rates a focus of new crop research

Not only could farmers reduce the amount of nitrogen applied across their crops, but the cost-saving exercise could also result in more even crops and an increase in yield.

The trial is investigating N management and water use efficiency in canola, with 16 different treatments, replicated and randomised four times across 64 different plots of Stingray TT canola.

While delved and clayed country north of Bordertown produces an average canola yield slightly less than two tonnes a hectare in an average season, Elders South East agronomist Adam Hancock believes the total should be above 2t/ha.

While water use efficiency was about 7-8 kilograms/yield/millimetre, Mr Hancock said it should be at about 11-12kg/mm.

“It seems canola paddocks are under fertilised, which reduces the risk, but also reduces the reward and with modern sowing systems and good weed control options, it’s probably time to raise the bar,” he said. 

The trial crops were sown on May 22 in the first year of the trial at Sherwood.

Drone normalised difference vegetation index and hand-held GreenSeeker optical sensors have been used to collect data to measure the correlation between N response and yield.

In addition to the NDVI footage, two tissue tests were taken, a Youngest Emerged Leaf-blade test and a second whole shoot test. 

“We’ve taken the opportunity to get a lot of data from the crop to try and improve the accuracy of tissue testing, which will tell us the chance of getting likely response from fertiliser,” Mr Hancock said.

Throughout the trial, six different N rates, ranging from zero to 150kg/ha have been applied and repeated using different timings and forms of N, and have taken into account background N levels and mineralisation.

“Not only are we looking at rates and timings of urea, but then we are looking at how that compares to other types of N with early and late applications,” Mr Hancock said.

“We are also seeing how late we can apply N and still capture all the benefits of putting it out.”

Mr Hancock predicted results would indicate farmers could go “harder” with fertiliser in canola crops and the average yield should be higher than it is presently.

“It will be about applying urea across the paddock at the rate it is needed rather than doing 80kg across the whole paddock,” he said.

“It might vary between 50kg/ha and 120kg/ha so there will potentially be less urea going out across the farm, but having more benefits and reducing costs."

Mr Hancock said many tractors and spreaders were “geared up” to distribute variable rates and utilise NDVI results, but it was a matter of obtaining the data to use the equipment.

“At present, we sample the paddock and stop 15 or so times, take a soil sample and put it in one bucket to see what the average is and then apply an average rate,” he said.

“This study will be about site specific management, rather than farming to the average; it’s about variable rate which will reduce variability across the yield map.”

The trial is funded by Incitec Pivot Fertilisers and managed in collaboration with Elders, while agricultural research company Kalyx manages the site operations and Southern Precision Ag collects the data.

STEVE Jaeschke is excited to host a canola trial on his property, hoping to improve his yields and gain insight into all his crop production.

Mr Jaeschke crops 4500 hectares of beans, wheat, canola, barley and hay at Sherwood.

The canola study is among a few research trials he hosts.

“We are trying to maximise return on the whole farm, so we plan to read the information from the canola crop and maybe apply some of those variations to the next crop,” he said.

“We could use a standard crop like canola, which is very responsive, to get more information for what the whole farm scale is, where the levels of nitrogen are and what they need to be to maximise returns.”

Mr Jaeschke said N levels were an issue in the area due to the relatively new country, delving and clay materials.