Protecting oilseed rape yields at harvest pays dividends

Oilseed rape losses at harvest have long been accepted as a consequence of growing the crop, but research into how this might be minimised has also quantified the impact on yield.

Independent trials performed by Nigel Metcalfe of NDSM Ltd in 2010 and 2011 compared the yield differences of strip trials desiccated with glyphosate only and those treated with glyphosate plus one of six pod sealers.

“The results were telling,” said Mr Metcalfe. “Pod sealers have a positive role to play in reducing the number of volunteer plants emerging after harvest through cutting losses caused by pod shatter both in the weeks after desiccation and at the time of harvest.”

“While all pod sealers do not perform the same, there is a clear benefit to be seen from their use through higher yields and reduced volunteers. In our 2010 trial the best performing pod sealer gave a yield benefit of 0.5t/ha over glyphosate only (control) and 0.2t/ha over the next best performing pod sealer.

“This was repeated in 2011 where Excalibur crops treated with the best performing pod sealer yielded 4.5t/ha compared with the 4t/ha for the control and 4.2t/ha for the next best performing product,” he added.

Weather events after crops have been desiccated have the greatest influence in determining the value of a pod sealer in protecting yield, but with oilseed rape prices for November 2012 trading at about £400/t the economic benefit of a pod sealer is clear.

A grower enjoying a similar result to that seen in the NDSM trial would see an extra £200/ha in output.  Pod-Stik from De Sangosse, the best performing pod sealer in NDSM trials, is available on farm for about £10/ha, giving a return on investment of 20:1 in the above example.

“There is extensive science behind modern pod sealers,” says David Foster, De Sangosse Technical Director. “The thin pliable layer of adhesive reduces pod splitting helping to cut losses and minimise volunteers. Across all trials the average benefit from including Pod-Stik is 200kg/ha, equivalent to £80/ha at current prices,” he adds.

The potential for losses is often drawn out over a lengthy period. From the moment the crop begins to ripen at Growth Stage 80-82 it has to endure potentially harsh weather, contrasting temperatures and the vibrations from the combine header.  Any of these can cause severe losses making pod sealers a low-cost form of crop insurance.

Growers planning to use a pod sealer to protect yields this harvest should follow manufacturer guidelines for best results, says David Ellerton, Hutchinsons Technical Development Director.

“Pod-Stik is one of the most impressive products I have seen,” said Dr Ellerton. 

“We have been involved with Pod-Stik since its launch in 2008 and our trials and commercial experience over the years testify to the phenomenal results seen in the field: volunteer numbers show to a line where it has, and has not, been used.

“Pod-Stik should be applied when pods are pliable (GS 80-82) to give cover through to harvest. It can be applied with a desiccant such as glyphosate or diquat or as a single application. Its benefits are the same in desiccated, swathed or naturally ripened crops,” says Dr Ellerton.

Growers should be aware however, of the need to rinse the sprayer after use. “We always advise growers to rinse the sprayer immediately after application with a non-ionic wetter to remove any remaining Pod-Stik,” adds Dr Ellerton.

USER EXPERIENCE

Nigel Durdy runs a family farm and contract farming business with his brother Adrian.  Each year N&A Durdy perform stubble-to-stubble operations on about 810ha (2000 acres) for eight farming customers south of Doncaster, Yorkshire.

With 323-404ha (800-1000 acres) of oilseed rape to harvest during the first three weeks of August Nigel Durdy, a former sprayer operator of the year finalist, takes a strategic approach to desiccation. By using three different desiccants he is able to manage the rate at which the crops ripen before combining.

“Depending on the expected weather and where we are with harvest I will use either Reglone (diquat), Touchdown Quattro (glyphosate with a water conditioner) or Roundup (glyphosate) to ripen the crop in seven, 14 or 21 days’ time respectively,” he says.

He is also the farm’s agronomist and over the years he has experimented with several pod sealers to establish their benefits. “I’ve tried most of them, but keep coming back to Pod-Stik; there are always fewer volunteers with it than any of the competitor products.”

The last two seasons have been kind at harvest, but having invested in the crop during the growing year and with values as they he is reluctant to drop Pod-Stik just to save a few pounds.

“Pod-Stik is a low cost form of protecting against avoidable losses.  Our experience suggests that it is a must when desiccating with diquat regardless of the season while if desiccating with glyphosate it comes down to your personal attitude to risk.”