AGROVISTA’S Chris Martin gave growers an update on oilseed rape performance from the company’s Grow- Crop Gold trials site at Croft, near Darlington, earlier this month.
The effect of various establishment techniques and the potential advantages of companion plants were the main subjects under discussion.
The prolonged wet spell both during and after the 2012 oilseed rape drilling season made it impossible for the trial plot seedbeds to be consolidated after sowing, Mr Martin said.
A range of drilling machinery was evaluated, including the Vaderstad Topdown and Biodrill, the Great Plains DTX and the Amazone ED precision drill.
Under these conditions, the Amazone drill had produced the best results due to its press wheel, which firms the soil behind individual coulters.
This machine topped the yield league.
Mr Martin said: “There was no opportunity for a post-drilling roll until the three to four leaf stage of the OSR. The cold, wet soils also increased slug pressure and plant populations were low in general.
“However, despite disappointing establishment rates across the board, all the drilling techniques managed to produce very respectable yields of four tonnes plus per hectare, as long as the crop had produced a minimum of five, evenly-spaced plants per square metre by harvest time. This is highly consistent with results from previous years and from other sites around the UK.”
Establishment was significantly improved where DAP (di-ammonium phosphate) 18:46:0 was applied at up to 165kgs/ha, in a band just below the seed. This created a “grow bag” environment for the emerging oilseed rape plant. DAP take-up was much greater when applied at planting, compared with an overall application at the early emergence stage.
The sowing of companion plants with oilseed rape also significantly improved establishment rates, added Mr Martin. While relatively common in France, this practice is fairly new to the UK, but has been trialled extensively at the Agrovista Growcrop Gold sites.
Early results suggest that it has considerable potential for growers in this country.
Overall figures from Croft showed that an extra 38 kg/ha of nitrogen was available to the oilseed rape in the spring, on plots where it had been grown alongside companion plants.
Where companion plants had been sown, there was a significant yield benefit from all three seed rates.
“The yield enhancement varied between 0.33t/hectare and 0.5t/hectare, with all the trials sites managing to produce a significant response.
The companion plants promoted oilseed rape rooting and growth without exception,” said Mr Martin.
“But we are still not sure whether this effect was due to the enhanced stimulation of soil microbes, or the ability of the companion plant roots to improve the soil structure."