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

Modern field pea varieties usually reach physiological maturity close to spring wheat maturity. Field peas can be swathed before combining or being 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 or warm temperatures.

""If green peas are swathed, a timely harvest is critical because the green pea is more susceptible to bleaching in the swath than if it is straight combined,"" says Hans Kandel, North Dakota State University Extension Service agronomist.

The bottom pods on the pea plant mature first. At physiological maturity, the majority of pods should have turned from green to yellow. With the yellow cotyledon types of field pea, the seed color also should have turned yellow. Swathing may result in some shattering, but this can be reduced by using 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 the swathed crop should take place as soon as possible because the swaths are sensitive to wind movement, 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 ideally should be combined with a seed moisture range of 16 percent to 18 percent.

""This will reduce splitting and cracking of the seed coat,"" Kandel says. ""At this moisture level, the seeds are firm. The best time to harvest is when the humidity is high because it reduces shattering. However, it is important that the vines are dry at combining; otherwise the harvest will be slow and difficult."

The combine reel speed should be set to slow to minimize seed shatter. Low cylinder speeds of 350 to 600 rpm are recommended to minimize cracking and splitting of the seed. Producers also should use full combine and portable augers at low speeds to reduce pea seed damage.

For more information on field pea production, go to http://www.ag.ndsu.edu/pubs/plantsci/rowcrops/a1166w.htm.

NDSU Agriculture Communication