Agronomy to help lift southern pulse performance
GroundCover™ Issue: 137 November - December 2018 | Author: Clarisa Collis
Pulse agronomy expert Jason Brand explores the latest trial findings to help lift pulse performance, profitability and adoption in the southern grains region
Agriculture Victoria’s Dr Jason Brand says GRDC-invested research in collaboration with Southern Pulse Agronomy (SPA) highlights the profitability of early sowing pulses as part of a strategy to help minimise crop losses from heat stress and drought in Victorian and South Australian farming systems.
Trials across Victoria last year, which included all rainfall zones, showed delaying sowing until mid-May caused gross margin losses from $200 to $250 per hectare in lentils and $100 to $600/ha in chickpeas.
“In the long term, early sowing (within the optimal sowing window from late April to early May) has generally proven profitable in Victoria,” Dr Brand says.
This is because delayed sowing exposes pulse crops – lentils, chickpeas, faba beans, lupins and field peas – to heat stress and rapidly drying soil in the flowering and podding growth stages during late spring, he says.
In 2017 trials at Ouyen in Victoria’s Mallee region, late-sown lentils, planted outside the optimum sowing window, averaged 37 per cent yield losses, while trials at Curyo (Mallee) and Rupanyup (Wimmera) saw the late-sown crop average 18 per cent yield losses. Trials were late-sown in late May in the central Mallee; in early June in the southern Mallee; and in mid-June in the Wimmera. The magnitude of late-sown pulse losses also depended on the cultivar. For example, where sowing was delayed in the Ouyen trials, lentil variety choice saw yield penalties range from one to 55 per cent.
Dr Brand says the research showed that, overall, PBA Jumbo2 was the highest-yielding commercial lentil variety, with stable performance across a range of southern growing areas and seasons. PBA Flash was the lowest-yielding lentil variety.
In field pea trials, PBA Butler emerged as the highest-yielding variety, outperforming its semi-leafless counterparts Kaspa, PBA Oura and PBA Gunyah.
Other GRDC-invested trials from 2015 to 2017 led by Dr Christine Walela from the South Australian Research and Development Institute (SARDI) looked at the efficacy of new active ingredients in foliar fungicides for controlling ascochyta blight in field peas in South Australia’s low and medium-rainfall zones.
These trials showed the fungicide Aviator Xpro® (bixafen at 75 grams per litre and prothioconazole at 150g/L) was cost-effective in controlling the early stages of ascochyta blight in field peas where yield potential was more than 1.5 tonnes per hectare.
“Early disease control with fungicides is important for reducing initial ascochyta blight infection,” Dr Brand says.
“And a late fungicide spray is important for controlling the disease in spring, when rainfall increases the risk of the disease spreading, as well as pod and seed infection.”
For example, where field peas were early sown at Hart in SA’s Mid North, the early application of Aviator Xpro® lifted yields by up to 20 per cent compared with the conventional industry practice of seed dressing using P-Pickel T® and two mancozeb fungicide sprays – nine weeks after sowing and at early flowering.
SARDI trials as part of the SPA project further showed sowing time influenced the efficacy of the new fungicide actives. “Grain yields increased where Aviator Xpro® was used on early sown instead of late-sown field peas,” Dr Brand says. “Results of the 2017 trials, however, need to be interpreted with caution as disease pressure was mostly low and its progression was limited by below-average rainfall.”
Trials at Streatham, Rupanyup and Ouyen also examined new genetic traits linked to weed management and Group B herbicide tolerance in lentils, faba beans and chickpeas.
Research looking at the elite faba bean PBA Bendoc found its grain yield was equivalent to the PBA Samira faba bean variety, but it had the added benefit of being more tolerant of imidazolinone and sulfonylurea Group B herbicides (regulatory and market approvals are ongoing for this elite line).
Dr Brand says Group B herbicide tolerance in PBA Bendoc has the dual benefit of providing growers with a new chemical control option as well as the opportunity to grow faba beans in paddocks with a history of Group B herbicide residues.
Another new faba bean is PBA Marne, an early flowering, high-yielding variety that has shown adaptation to the lower-rainfall and short-season areas in southern Australia.
PBA Marne could expand faba bean production into areas that are currently considered marginal and improve reliability in established areas during below-average rainfall seasons.
But seed supply for these new varieties may be limited due to the dry conditions in 2018.
Another component of the SPA research led by Dr Christine Walela looked at how delaying harvest affects the quality of mature pulse crops.
For example, 2016 trials in SA found harvesting within the optimum window – 10 days after pulse crops reach physiological maturity – was important for retaining grade one quality attributes. Specifically, these attributes relate to grain weight, seed coat colour and wrinkling, and screenings for split and cracked grain.
But postponing harvest after this optimum window, effectively increasing exposure to rainfall and sunlight, downgraded grain quality across all pulse crops: lentils, field peas, chickpeas and faba beans.
This ongoing research also suggested some crop varieties were more sensitive to late harvest damage.
For instance, when lentil harvest was delayed for a month after the crop reached physiological maturity, there was spike in screenings and reduced seed weight for PBA Blitz, PBA Giant and PBA Greenfield varieties.
Nugget, PBA Flash and PBA Hurricane XT lentil varieties maintained grade one seed coat colour when they were taken off a month after reaching physiological maturity.
Dr Jason Brand
0409 357 076
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