Fall-seeded Peas, Lentils Show Promise as Economical N Source

Montana study reveals nitrogen provided for subsequent wheat.

Published on: Jun 18, 2008

Projected production budgets show a potential for increased farm profits using fall-seeded peas and lentils for spring grazing as a nitrogen source for subsequent wheat crops, Montana Agricultural Experiment Station studies reveals.

Nitrogen benefits to follow crops could average more than $30 in net per-acre benefits, estimates Dave Buschena, a Montana State University economist.

An additional $10 an acre plus could be reaped from grazing off the legumes, he notes.

"The estimates of nitrogen and haying or grazing benefits of the pea crop appear to offset the seed and machinery operating costs for peas," he says. These returns should be compared with the cost of chemical or tillage fallow, Buschena notes, which are currently estimated to be almost $25 an acre, instead of the pea crop.

His budgets were used for the pea crop to add 50 pounds of N to the soil under grazing and 40 pounds under haying. These levels are estimated based on previous studies. Actual nitrogen benefits will be less in drier zones and in drier years, and greater under wetter conditions, he explains.

This N benefit from peas reduced, but did not completely eliminate, the amount of urea that is needed to be applied to a subsequent wheat crop, he adds.

Projected benefits, however, need to be verified in practice, researchers warn. That effort is already underway at the MSU research station near Moccasin, Mont., where researcher Chenghi Chen launched such an effort last fall.

Research focusing on saving fertilizer costs for farmers is increasing in the West as cost of nutrients continue to rise. Using either an intercrop or rotation with legumes could give an economic benefit to both conventional and organic farmers, says MSU's Clain Jones, a soil fertility specialist.