With increasing interest in other break crops alongside OSR – enforced by the season and establishment challenges – pulse crops’ prospect are under the spotlight too.
Oilseed rape growers are being urged to focus agronomy efforts on increasing the number of seeds produced per sq.m, with a target to hit more than 100,000/ sq.m to give the crop a chance of yielding more than five tonnes per hectare.
At the latest iOSR meeting, growers heard that seed number is the most significant factor explaining variation in yield, according to results for the YEN (Yield Enhancement Network) initiative.
Dr Sarah Kendall of ADAS reported that over the past three years there had been a clear correlation between crops with greater seed numbers delivering higher yields.
The other key influences explaining variation in yield have been the total biomass For more on this series, visit the iOSR hub at fginsight.com/iosr-hub Follow the discussion: #iOSR and stem biomass, with an aim to target the optimum canopy size at flowering, she said.
The work showed pod biomass has a far smaller effect on yield variation, as does thousand seed weight or harvest index.
Dr Kendall highlighted that among the YEN growers, the top 25% of performers achieved an average yield of around 5.8 t/ha, compared to less than 3.75 t/ha for the bottom 25%.
In the same pattern of associations between crop management and yield, the top 25% of growers maintained an average 95-day-plus period from flowering to desiccation, compared to 85 days for the bottom 25%, with the mid group averaging 89 days.
In other associations noted by the report, the top 25% growers made more fungicide applications, 3.6 per crop compared to three for the bottom 25%, along with more plant growth regulator use by the higher yielding quartile.
“There was also a trend for growers of higher yielding crops to establish fewer plants per sq.m and use more fungicides,” advised Dr Kendall.
“High yielding crops had an average 11 extra days from flowering to desiccation.”
Also speaking to iOSR growers, Syngenta technical manager Georgina Wood advised the use of a spring plant growth regulator (PGR) to manage the main raceme and encourage greater side branching.
This could help build a strong crop architecture at flowering, she said.
“Plants are inclined to race through the growth stages in spring, which can lead to the dominance of the main stem and limited or late flowering on side shoots.
This could restrict the capability for pod creation and overall number of seeds produced.
“Where there are sufficient numbers of plants and established biomass, a PGR application at early stem elongation can help balance the plant’s growth and fully develop the crop canopy.” Yields Miss Wood added that for all crops, maintaining the green leaf area for longer has consistently delivered higher yields, as well as enabling the crop to fill heavier seeds and increase oil content.
“A one- or two-spray programme with Amistar, from mid- to late-flowering, provides the physiological greening effect which will boost yield in every season, along with disease control when the conditions demand,” she advised.
Pulse crops are among the key spring break crops being looked at by growers this season.
However, climatic trends in recent seasons, with periods of prolonged hot dry weather over summer, has seen an increased threat of rust in bean crops.
Furthermore, with the final use of chlorothalonil-containing products, including the widely used Alto Elite, by May 20 this year, growers require a new fungicide strategy for 2020 and beyond.
Syngenta technical manager Michael Tait said that, for this season, growers should look to make an Alto Elite application by May 20 to prevent initial chocolate spot infection, followed by Amistar in mid-June for late rust.
“Trials in 2019 showed an Amistar application during the fast development of the canopy gave its best results from the systemic activity, to protect against rust.” For disease strategies in 2021 and beyond, he reported new Syngenta fungicide chemistry for pulse crops had been submitted for registration.
Trials have shown the Solatenol active is an ideal option for an early T1 application, targeting the early development of chocolate spot and Ascochyta.
Break crops are set to have an increasing role in longer arable rotations, with the focus on soil health and sustainable systems.
New research by the Game and Wildlife Conservation Trust (GWCT) and NIAB, as part of the Syngenta Conservation Agriculture Initiative, will assess the implications of OSR and beans for soil structure and health, farm biodiversity and profitability, through a whole farm rotation.
Phil Jarvis of the GWCT said the value of break crops needed to be counted in a whole rotation benefit, including grass weed control and fertility building.
Implications of fallow years, cover crops or integration of stewardship options also needed to be included.
Where light till practices were used to establish crops, compared to a conventional plough for example, the numbers of farmland birds and earthworms had increased, along with reduced carbon dioxide emissions.
These could be just the societal benefits for which growers would be paid under a new regime.
Soil benefits from rooting, legume fertility and adoption of low-till establishment suited to break crops could all feature in future systems, he highlighted.
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