Small grain and forage pea mixtures: A forage option

With good management, small grain and pea mixtures can be a good forage source and companion crop for alfalfa or mixed hay seeding.

In years when forages are in short supply, or winter-kill in alfalfa has been a problem, small grain/forage pea mixtures should be considered. For new alfalfa or mixed hay seedings, small grain/forage peas make a good companion crop, competing well with weeds and protecting vulnerable soils from erosion. Key decisions for success with small grain/forage peas include selecting good small grain and pea varieties (or pre-mixed seed), seeding rate, soil fertility and harvest timing.

A couple of noteworthy variety choices include ForagePlus oat, a variety developed by the University of Wisconsin. Dry matter yields of ForagePlus are about 25 percent higher than that of the highest yielding standard oat varieties, according to several years of University of Wisconsin variety testing results. This large yield advantage comes with a corresponding disadvantage of lower feed value, particularly protein. Low crude protein content will be improved by adding forage peas into the seeding mixture.

A pea variety of special interest is the 4010 variety of Canadian speckled pea, developed for higher forage yields and improved standability. At least one Upper Peninsula beef producer reports planting 4010 peas with hybrid sorghum-sudangrass this spring, with peas “keeping up” with the rapidly growing forage grass. Trapper forage peas are also a long-time and proven variety. Arvika is a dry-land forage pea showing good performance in the Dakotas.

Seeding rates for small grain/forage pea mixtures should be based on seed size and desired number of established plants per square foot, not just on pounds of seed per acre. A goal of 10 to 15 oat seeds/square foot (30 to 45 lbs/a) and four pea seeds/square foot is recommended. There is considerable variation in pea seed size. Although pea seeding rates up to 100 lbs/acre show modest yield increases, a maximum of 50 pounds per acre of smaller seeded peas, such as Trapper, is recommended. For larger seeded varieties, this lbs/acre rate will increase. If alfalfa or clovers are underseeded (with or without grass), seeding rates should be reduced 30 percent to limit competition with the legume.

Fertilizer requirement for small grain/forage pea mixtures alone, or with alfalfa or other underseeding, will vary based on soil fertility levels. Detailed information on crop removal and fertility requirements can be found in the University of Wisconsin Extension publication A2809, Nutrient Application Guidelines for Field, Vegetable and Fruit Crops. Small grain/pea forage will remove about 11 pounds P2O5 and 44 pounds K2O per acre per dry matter ton harvested. On lower fertility, low organic matter soils, about 25 pounds actual nitrogen per acre should be applied if an underseeding is not included. With underseeding, N rate should be reduced to 15 pounds per acre. On low fertility soils (55 to 70 ppm potassium and 10 to 15 pounds phosphorus), 55 pounds P2O5 and 150 pounds K2O per acre will be needed to produce a 2 to 3.5 ton/acre crop. Soil testing will provide accurate fertilizer recommendations.

Harvest timing should be based on maturity of the small grain component. For best quality, harvest when the small grain is in the boot to early heading stage. If optimum quality can be sacrificed to capture more yield (for beef cows, dry dairy cows, etc.), then wait until the small grain reaches soft dough stage.

For more details, view these informative University of Wisconsin Extension publications:

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