ISSUE 12    July 26, 2007


Current North Dakota State University Extension recommendations and guidelines for canola is to swath at the optimum stage to reduce green seed and seed shatter losses. The canola swath is allowed to cure and ripen for a minimum of 10 to 14 days before combining. From 2004-2006 there have been a number of small scale and field scale studies comparing straight combining canola with traditional methods of swathing and combining. The results of this research indicate that canola can be successfully straight combined. All combine headers; rigid, flex, and draper all performed well with straight combining canola and did not cause any harvest loss compared to the pick-up head.

When harvested at the optimum time, straight combining canola can be successful with equal to higher yield than traditional harvest methods of swathing and combining. There is also less green seed and generally higher oil content and test weight with straight combining verses swathing and combining. One important consideration with straight combining is that it is more vulnerable to seed and shatter loss when harvest is delayed past the optimum. It is very important when straight combining canola to harvest at the optimum time.

The optimum harvest time is identified as the first time the harvest moisture falls below ten percent. Research trials indicate that seed loss due to shatter increases significantly approximately 10 days after the optimum harvest time was reached with straight combining. Spodnam/Biovital is a polymer that has been developed to reduce the seed shatter loss in pod-bearing crops. Spodnam or Biovital was evaluated at many trial locations. There was no difference in yield with the straight combining treatments with and without Spodnam/Biovital when canola was harvested at the optimum time or when harvest was delayed past the optimum.

Kent McKay
Area Agronomy Specialist
North Central Research Ext. Center



If field peas are sold into the food market for human consumption, harvest timing is critical. If the peas are bleached, split, cracked or if the seed is stained, the peas may end up as livestock feed.

The modern field pea varieties usually reach physiological maturity close to spring wheat maturity. Field peas can be swathed before combining or straight (direct) combined. Peas may be swathed if the crop maturity is uneven or if there are many green weeds in the field. If the harvest of green cotyledon peas is delayed the seed coat may bleach. Bleaching can occur when there is rainfall at maturity, high humidity, bright sunshine and warm temperatures. If green peas are put into the swath a timely harvest is critical as the green pea is more susceptible to bleaching in the swath than if it is straight combined.

The bottom pods on the pea plant mature first. At physiological maturity the majority of pods should have turned from green to a yellow color. With the yellow cotyledon types of field pea the seed color should have turned yellow. Swathing may result in some shattering, but this can be reduced with vine lifters and pickup reels so the peas can be lifted over the cutting knife. The best time for swathing is early morning or late afternoon/evening when pods are tough. This will reduce shattering losses. Combining of the swathed crop should be done as soon as possible as the swaths are sensitive to movement by wind, which may increase shattering losses.

Straight combining is possible if the variety is standing up, the field is evenly mature, and the harvest equipment has a floating cutter bar or a flex head. Lifter guards and pickup reels also improve harvest efficiency.

Field peas should ideally be combined with seed moisture range for harvest between 16-18%, this will reduce splitting and cracking of the seed coat. At this moisture level the seeds are firm. The best time for harvest is with higher humidity conditions to reduce shattering, however, it is important that the vines are dry at combining otherwise the harvest will be slow and difficult.

At harvest the reel speed should be slow to minimize seed shatter. Low cylinder speeds (350-600 rpm) are recommended to minimize cracking and splitting of the seed. Use full combine and portable augers at low speeds to reduce pea seed damage. For more information about Field Pea Production see Extension publication A-1166 at

Hans Kandel
NDSU Extension Agronomist
Broadleaf Crops



Small grain fields are nearing harvest. Several herbicides are labeled for pre-harvest weed control and as harvest aids in barley and wheat. Pre-harvest herbicides can aid in the control of perennial weeds and other green weeds that hinder the harvest operation. Weed control with pre-harvest herbicides, however, is generally disappointing as weeds at this time are tall, nearing maturity and slow growing. Furthermore, green weeds can take a week or more to dry down even with an effective treatment.

Glyphosate, in addition to controlling weeds, is labeled for use in aiding the dry down of the crop itself (as opposed to controlling and drying down weeds in the crop). Glyphosate is a systemic herbicide and takes from 7 to 10 days to effectively kill the growing parts of the crop so the dry down process is not immediately visible. Traditionally, fields that had excessive green material were swathed. Swathing enables faster dry down than pre-harvest glyphosate if significant levels of green material are present in the crop. A standing crop that has been treated with glyphosate, however, will dry faster than a swathed field after a rain.

Glyphosate should only be applied after the crop has reached physiological maturity which for most varieties occurs at a grain moisture content of about 30%. At this moisture content the grain is in the hard dough stage and if you run your thumb nail across the kernel, the indentation will remain. Applying glyphosate before physiological maturity can reduce yield, test weight and seed germination. Because germination can be affected when applied too early, glyphosate should not be used in fields that will be used for seed or on barley intended for malt. Pre-harvest applications of glyphosate must be made at least 7 days before harvest.

For addition information about pre-harvest applications of herbicides refer to the 2007 Weed Control Guide and the labels of approved products.

Joel Ransom
NDSU Extension Agronomist - Cereal Crops

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