Field Peas and Lentils in Crop Rotations New crops can provide diversification in farm enterprises, build soil fertility, and fill niches in crop rotations. Field peas and lentils are two legume crops which may fit the bill for some Northwest and Northern Plains crop farms. Field Peas Field peas are a cool-season annual legume with weak stems and a viny habit. A useful crop, they are grown for seed, forage, and as a nitrogen-producing green manure.
Field peas work well as a summer green manure.
If planted with a small grain, the crop also smothers weeds. Grown alone or with small grains, it makes good livestock feed, although the hay may be hard to cure. When harvested for grain, peas are commonly swathed and picked up with the combine. The Palouse region of Washington supports much of the US dry pea production, and production is expanding into other regions. Field peas do best on loamy, well-drained soils with a pH from 5.5 to 7 and moderate fertility.