Be brave and cut oilseed rape seed rates
Be brave and reduce seed rates, was the key message from the results of the Grow Crop Gold trials carried out by Agrovista.
“Highest yields during the three years have always been achieved with lower seed rates on good seed-beds, with adequate moisture resulting in evenly established low plant populations in the autumn,” said technical manager Mark Hemmant at the Agrovista GrowCrop Gold grower meeting at Harper Adams University College.
Lower seed rates were beneficial where rapid establishment occurred. Results from the three trial sites found 21 seeds/sq m averaged 78% establishment, while 123 seed/sq m averaged 54% and 50 seeds/sq m gave 63% establishment.
One trial site averaged better with more seeds/sq m, but this was due to issues with cabbage root fly, thus highlighting the fine line when using low seed rates.
“I can’t say this is the seed rate you should use, although we have set out some useful guidelines, because there are many factors that come into it. What I will say is growers need to be braver with drilling rates.”
Competition between oilseed rape plants in the same row appears to be more important than between rows. Typically, the highest yields have been achieved sowing 15-20 seeds/m row length. Increasing the number of seed/m row reduces the percentage establishment through competition.
“We think wider rows will become more widespread in the future to comply with environmental legislation and to make better use of inputs.”
Results showed that increasing the row width from 125mm to 150mm, 500mm or 750mm did not reduce yield. They also showed little overall difference between a narrow or wide seed band width.
“Wider rows and lower seed rates involve a change of mindset and of course can be risky. But if you invest time into getting the detail right, then the rewards can be great,” added Mr Hemmant.
Don’t give up on backward oilseed rape just yet
