A National Hay Agronomy trial at Hart Field-Site has revealed that certain early-sown hay varieties, when given an increased nitrogen application at the correct growth stage, could deliver higher yields than later-sown crops.
SARDI senior research officer Courtney Peirce and Hart regional intern Brianna Guidera presented the trial's findings at a recent Hart field day to provide growers with the latest information on improving oaten hay production and quality.
The Agrifutures-funded trial is about to enter its third year of a four-year program researching management practices of nitrogen application in hay crops, and whether time of sowing and variety also helps to improve hay yield and quality for the Australian export market.
The Hart site is one of four trial sites across the country, with plots at Muresk, WA, Birchip, Vic, and Yanco, NSW.
Hart research and extension manager Rebekah Allen said the trial aimed to research two different sowing times.
"We used the traditional early May sowing time and a late May to early June sowing time," she said.
Three nitrogen rates were used - 30 kilograms a hectare, 60kg/ha and 90kg/ha.
Nine varieties were used in the trial - Durack, Brusher, Carrolup, Koorabup, Mulgara, Vasse, Williams, Yallara and Wintaroo.
"Three varieties, Yallara, Mulgara and Wintaroo, had additional nitrogen rates of 10kg/ha, 120kg/ha and 150kg/ha, to capture and validate a nitrogen response curve," Ms Allen said.
Nitrogen applications were split, with two-thirds of each nitrogen ration applied at seeding and one third applied at the tillering stage in mid-June to early July.
Hay cuts were then taken to determine hay yield and are currently undergoing analysis for quality.
The 2019 trial results were mixed because of drought-like conditions and frost causing a decile one growing season but yield gains were observed for varieties sown in early May.
"Yields were also increased with nitrogen applications increasing from 30kg to 60kg of N/ha," she said.
"But, these responses were not seen for varieties sown in early June because of poor in-season rainfall."
The best performing varieties for hay yield when sown in early May were Wintaroo, Mulgara, Yallara and Brusher.
"All varieties met grade one hay quality requirements," Ms Allen said.
Further information about the national trial results is available on the Hart Field-Site website.
PROMISING RESULTS IN HART HAY TRIAL
A HART Field-Site hay trial has resulted in "positive" differences in hay yield this year, after a rise of more than half a tonne a hectare was recorded.
The trial researched the degree to which sowing dates, nitrogen rates and hay variety impacted on yield.
Hart regional intern Brianna Guidera said the results were promising.
"On average, early May-sown plots yielded higher, at 3.4 tonnes/ha, compared with late May sown plots that reached 2.7t/ha," she said.
Ms Guidera said post-seeding and early winter conditions were dry, with a June/July combined rainfall of just 38 millimetres.
"This led to sustained water and nitrogen stress throughout key plant developmental stages such as tillering," she said.
Plots that were treated with 10 kilograms of nitrogen a hectare yielded less than those treated with 30kg of N/ha, resulting in 2.7t/ha and 3.1t/ha crops.
Fertiliser rates above 30kg/ha did not provide a yield benefit.
"This was because dry conditions limited nitrogen uptake by plants," Ms Guidera said.
Brusher, Carrolup, Yallara, Wintaroo and Durack were high yielding, with Brusher yielding the most at 3.5t/ha, while Vasse, a long-season variety, was the lowest, yielding 2.3t/ha.
"At cutting, many Vasse heads were trapped in the boot but still maturing," she said. "Hay quality results will be coming soon."
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