![Research has documented large variety differences for tolerance to wet harvest conditions, wind damage and ability to stand up. It is important to consider these features along with yield ability quality and disease resistance of any given variety. Research has documented large variety differences for tolerance to wet harvest conditions, wind damage and ability to stand up. It is important to consider these features along with yield ability quality and disease resistance of any given variety.](/images/transform/v1/crop/frm/silverstone-agfeed/2078925.jpg/r0_0_1024_875_w1200_h678_fmax.jpg)
PROLONGED wet and/or severe wind leading up to harvest has often results in big cereal yield losses, often more than 2.5 tonnes a hectare, as well as quality downgrades.
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Recent and ongoing research indicates some barley and wheat varieties cope better with these conditions, hardly losing any yield, compared to a susceptible variety losing more than 2.5t/ha from either or both severe wind and rain events.
Research in South Australia, at Turretfield and Moyhall, during 2012 and 2013, documented big barley variety differences from wind and rain leading up to and around harvest.
The research is by the South Australian Research and Development Institute with Grains Research and Development Corporation (GRDC) funding, under the direction of Kenton Porker and Rob Wheeler.
Varieties were measured at physiological maturity and again more than 30 days later after significant rainfall and wind conducive to head loss and quality downgrading.
Of 24 varieties assessed, yield loss from delaying harvest has been most prevalent in Sloop SA, a variety known to have poor head retention.
In some trials grain yield losses were greater than 2t/ha between harvest dates.
The researchers noted newer barley releases have not been as susceptible to head loss as Sloop SA.
Of the newer releases Oxford did not incur significant yield losses from a delay in harvest across all three sites/seasons.
Granger and Bass also demonstrated good head retention with minimal yield losses.
Hindmarsh and LaTrobe have both displayed superior straw strength and reduced lodging compared to other varieties such as Keel, Skipper, and Fleet when harvest was delayed.
However, their improved straw strength has not necessarily translated to improved head retention, with both Hindmarsh and LaTrobe recording large yield losses from a delay in harvest at more than one site/season.
The researchers stress other factors can contribute to head loss: disease, stress and or changes in environmental conditions coinciding with the development period for a variety (maturity) may influence the severity of head loss.
For example leaf rust and spot form of net blotch infections may contribute to weakening of plant structure and result in greater head loss.
Barley fungicide trials have shown a late spray to protect against leaf rust significantly reduces lodging and head loss in susceptible varieties.
Research by NSW Department of Primary Industries (DPI) at Tamworth, involving senior technical officers Stephen Morphett and Bruce Haigh, also noted big variety differences with delayed harvests.
Long delays in 2011, 2012 and 2013 trials noted variety yield losses varying by more than 1.5t/ha and downgrades in grain quality.
Up to 16 varieties were harvested each year from two to four harvest dates, beginning at physiological maturity.
In some cases there were large rainfall (more than 100 millimetres) events between early and late harvest.
For example delays in harvest at Tamworth in 2011 from November 11 to December 7, where 215mm of rain fell resulted in big yield losses for Fitzroy and Buloke (2.2t/ha and 2.1t/ha). In contrast Roe, Vlamingh and Grout suffered much smaller losses (0.5t/ha to 0.7t/ha).
Commander, Gairdner, Hindmarsh and Shepherd all had similar yield losses (average 1.2t/ha) from a longharvest delay at Tamworth.
Averaged over all varieties assessed in the 2011 wet harvest yield losses increased with time with the loss being on average 1.7t/ha where harvest delay was longest (December 7). Delaying harvest also had an effect on all grain quality attributes.
However, Guy McMullen research leader of northern farming systems and director of the Tamworth Agricultural Institute noted grain quality was relatively unaffected for a variety like Gairdner despite all the rain at the latest delayed harvest.
Full details of the research are available on the GRDC and NSW DPI web sites.
Next week: Fertiliser improves quality and quantity of native pastures and with careful management is compatible with their long term persistence.
Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact 0428 752 149.