Field Peas Create Benefits as a Winter Forage Legume

By Anowar Islam, UW Extension Forage Specialist

Peas are a cool-season legume commonly planted for edible seed or seedpods.

They are called by many names, based on their uses. For example, we see field peas, garden peas, spring peas, English peas, common peas, green peas and Austrian winter peas. Garden and green peas are harvested before the seed is mature while field peas and Austrian winter peas are harvested when seeds are mature. The dry seeds are primarily blended with grains to strengthen the protein content of livestock feeds.

Dried peas, either whole, split or ground, are used for human consumption, too. They are a nutritious legume and contain 15 to 35 percent protein and high concentrations of the essential amino acids, such as lysine and tryptophan.

Field peas are a very important legume crop that have many uses. Peas are used as a forage crop, rotational crop, green manure or as a cover crop.

In their use as a forage crop, peas are planted alone or with cereals for making silage and green fodder. Pea plants can be grazed by animals directly. Field peas can be grazed multiple times, depending on the management and environmental conditions, as they have regrowth ability.

For use as a rotational crop, peas can provide many advantages. They may break up disease and pest cycles and add nitrogen to soil thus improving soil microbial activity, soil aggregation and soil water conservation. They may also enhance farm profitability.

Peas can also be used as a good green manure and cover crop. They grow quickly and add nitrogen to the soil through the nodulation by symbiotic association with Rhizobium bacteria. The most common pea used for green manure or cover cropping is the Austrian winter pea. It can produce 90 to 150 pounds of nitrogen per acre when grown as green manure crop. They are well adapted to cold temperatures and fit into many crop rotations, including winter wheat-fallow rotations.

Peas can be grown in a wide range of soils and weather conditions. However, they are not tolerant to salinity or extreme acidic soils. They grow well in the soil pH of 5.5 to 7.0 with 16 to 39 inches annual precipitation. Winter field peas are extremely winter hardy.

Peas can be planted in the spring or fall. For better nodulation and nitrogen fixation, peas should be inoculated with pea-specific Rhizobium bacterial inoculants prior to planting. Seeding rates vary depending on the need and objective of planting. However, typically 50 to 80 pounds per acre for drilling and 90 to 100 pounds per acre for broadcast are recommended.

Compared to alfalfa and other forage legumes, pea seeds are larger and can be planted at a depth of 1.5 to three inches with row spacing of six to 12 inches.

Initial weed control is necessary for successful stand establishment.

Peas are easy to kill using herbicides, mowing or disking. They are susceptible to multiple foliar, root and seed diseases.

There are several pea cultivars commercially available in the market. It is recommended that producers should purchase certified seeds based on their needs and objectives. Researchers at the Department of Plant Sciences in the College of Agriculture and Natural Resources at the University of Wyoming are conducting regional field evaluations on some recently developed winter field pea lines.

It is anticipated that new cultivars specifically suited for Wyoming environments may be released soon.

Anowar Islam is an associate professor and the University of Wyoming Extension forage specialist in the Department of Plant Sciences in the College of Agriculture and Natural Resources. He can be reached at 307-766-4151 or mislam@uwyo.edu.