Little benefit was seen in tests on pod sealants, while glyphosate trials showed it is an effective crop dry-down aid
INDIAN HEAD, Sask. — A Saskatchewan research organization is looking at how to reduce the risks of straight-combining canola now that the practice has become more commonplace.
“Ten years ago there was only a smattering of farmers straight-cutting canola, but today it’s an accepted harvest method,” Chris Holzapfel, research manager at the Indian Head Agricultural Research Foundation, said during the farm’s recent field day.
“I have more extensive experience with the two LibertyLink varieties, but several new Roundup Ready varieties are geared toward straight-combining and showing excellent pod-shatter tolerance, yield and standability,” he said, adding that even with non-shatter-tolerant varieties the losses were often negligible.
“Over 13 site years with straight-combining and normal harvest dates, we recorded yield losses below 10 percent in all cases and were usually well below five percent. When harvest was delayed, losses were still often remarkably low, but in extreme cases could be severe. In 2012, with very heavy sclerotinia pressure and high winds, we had more than 50 percent losses at one site with certain varieties. Many swathed fields were just as bad that season due to the 80 km-h winds.”
In 2009-10, Holzapfel led a project for SaskCanola with pod sealants at four locations testing different products across multiple varieties.
While the sealants showed some benefit, it was inconsistent and difficult to predict at 40 to 50 percent pod colour change when the products had to be applied.
Only one out of eight site years showed a yield benefit with a pod sealant and straight-cut combining. However, there was little overall difference between treated and untreated canola, which made it difficult to justify the added expense.
Holzapfel said it wasn’t always the fault of the sealant because sometimes harvest was delayed beyond what the sealant could be expected to provide protection.
He said he sometimes still uses a sealant in his research, but it’s too inconsistent from a production perspective to recommend to growers planning to straight-combine.
Farmers are still debating whether to apply glyphosate ahead of straight-combining canola.
Holzapfel said it can help kill and dry down weeds before harvest if applied properly ahead of time. However, producers shouldn’t rely on it to help dry down the crop, he added, because that’s not what it’s registered for.
“In a wet fall last year, we applied glyphosate and left it about 20 days to work,” he said.
“It helped to dry down the crop quite effectively relative to the untreated control. Given enough time and in the right conditions, when growing Liberty or Clearfield varieties, you can actually have a strong dry-down effect with glyphosate. However, it isn’t always the case, depending on weather and crop stage.
“Reglone and Heat LQ are the most reliable harvest aids for crop dry-down under late stages and a wider range of conditions. Reglone is an effective crop desiccant for a wide range of growing conditions. It doesn’t need to be taken up by the plant through the roots and can literally work within four days, depending on the weather,” he said.
“Heat, when tank mixed with glyphosate, gives powerful weed control, and the Heat component is a more contact-based herbicide that is quite non-selective against broadleaf crops and weeds. It would normally provide a more rapid and reliable dry-down compared to glyphosate applied alone. I consider it an intermediate between the (glyphosate) and Reglone. It doesn’t appear to be as rapid as Reglone, but we’re still comparing all the options and need more data. Last year we didn’t get the same level of dry-down with Heat as Reglone in the time window we gave it, but all were a big improvement over control.”
The final piece of a more successful canola harvest is in the hands of the equipment and the fine-tuning of the settings.
A number of straight-cut headers are on the market but IHARF, in a project led by the Prairie Agricultural Machinery Institute, has observed slight advantages using a Draper rigid auger-type header modified specifically for straight-combining canola.
The ability to move the position of the knife ahead about 20 inches allows an operator to cut the canola before the reel comes into contact with it. It also provides a larger catchment area for any seeds that do shell out.
However, Holzapfel said any straight-cut header can be used with a good operator and proper settings. It just takes a bit more time and patience to get things right.