DIALLING in on the most effective fertiliser rates and getting the best bang for a grower's buck from applications are among the catalysts behind a grain nutrient testing program at Pinnaroo.
Initialised by Pinnaroo Fertiliser's Heath Boseley at the end of 2018, growers in the region have sent in samples after the previous two year's harvests to see how long-held rules of thumb about nutrient removal from paddocks stacks up against what the tests show.
Pinnaroo cropper Giles Oster, who grows wheat, barley, canola, vetch and lentils across 2600 hectares, is part of the new program and said he would be able to use the grain nutrient testing results in conjunction with their regular soil testing to maximise the efficiency and effectiveness of their fertiliser replacement program.
Mr Oster said although he had only used the grain testing data for one season and expected its usefulness to grow exponentially as data from more seasons was collected, they had already made some slight adjustments based off the information collected by Mr Boseley.
"Last year we pulled our phosphorus rates back a fair bit based on what was removed from the crops the previous seasons," he said.
"We married that up with some deep soil nitrogen testing, which we did in the autumn of the previous year, and we had to put our nitrogen rates up a little bit.
"From the previous season, we didn't have as much nitrogen fixed as expected, even where we had grown legumes.
"We were able to marry the grain test results that Heath had, in terms of phosphorus removal, and used that in conjunction with the deep N soil tests we did to work out a program."
Mr Oster said he was most interested in gauging residual soil levels of the nutrients nitrogen, phosphorus and sulphur, with maximising their bottom line the major drawcard of the testing program.
"It's about getting a better bang for your buck and saving a dollar where you need it," he said.
"Every dollar we spend, we need to justify why we're spending it.
"Testing is about putting the fertiliser and money where it needs to go."
NO LONGER RELYING ON RULES OF THUMB
UPDATING long-held assumptions about the nutrient removal from paddocks after harvesting was the catalyst behind a district-wide grain testing program started by Pinnaroo Fertiliser's Heath Boseley.
Two years of testing have been conducted thus far, with results after the 2018 harvest showing nutrient removal differed from the figures growers in the region generally worked from.
Mr Boseley said most Mallee growers worked on the assumption a wheat crop removed three kilograms of phosphorus and 40kg of nitrogen per tonne of grain.
"The data is pretty old, it's not specific to the Mallee and it's not based on the type of seasons we're now experiencing, so it was time to ground truth these figures with some testing," he said.
Mr Boseley sent all customers sample bags to be returned to him with a small sample of grain.
Based on the 50 grain test results he received back from the Nutrient Advantage laboratory, Mr Boseley found the average phosphorus removal was 2.7kg/t of grain for that season.
"So far we only have one year's data to go on, but in the next few years we'll start to build a more complete picture of nutrient removal from Mallee crops," he said.
Mr Boseley planned to collect nutrient removal data for the next three to five years, with the early information already proving valuable.
Grain nutrient removal figures were used in nutrient budgeting, along with yield results, paddock histories and soil test results, to ensure enough fertiliser was applied for following crops and to avoid nutrient run-down.
Start the day with all the big news in agriculture. Click here to sign up to receive our daily Stock Journal newsletter.
