UI Extension study shows promise for raising, grazing cover crops after grain harvest

An ongoing University of Idaho Extension trial shows early promise for east-central Idaho farmers and ranchers hoping to raise two forage crops from a single field within the region’s short growing season.

The trial is in its second growing season at U of I’s Nancy M. Cummings Research, Extension and Education Center in Salmon and will continue for another one to three years. Led by Extension beef specialist John Hall, the project entails planting fall triticale, swathing and baling it as hay in June, applying herbicide to prevent regrowth and then planting a multi-species cover crop mixture.

Cover crops are generally planted primarily for soil-health benefits — such as fixing nitrogen, improving soil porosity and boosting soil organic matter — and often offer the farmer no direct commercial benefit. Hall and his colleagues, however, chose to graze their cover crops in the fall, prior to planting another triticale crop, to capture the value of the forage, while also returning nutrients and minerals to the soil through cow manure.

Dual-crop strategy

The team showcased the cover crops trial on Sept. 9, 2025, during a field day at the research facility.

“Our main objective last year was to demonstrate we could use cover crops in this area of the state, graze with cattle and get good weight gains,” Hall said. “We were also demonstrating fencing systems and what’s entailed with grazing cover crops.”

Throughout the trial, the experimental field will not be tilled — saving fuel by reducing equipment use, preserving soil carbon that would otherwise be released as greenhouse gases, and maintaining soil structure and living roots essential for soil health.

Hall knows of one area ranch that raises annual forage mixes as cover crops and grazes them, but few, if any, area producers have tried raising and grazing cover crops in the same growing season following a commercial crop — convinced the season would be too short. Though Hall and his team have yet to calculate their economic returns, they’ve demonstrated cover crops planted in Salmon can yield significant forage in a short timeframe. In fact, last fall they struggled to keep up with the rapid growth of their cover crop when they grazed 30 yearling heifers across a 29-acre field divided into 15 paddocks, rotating the livestock to a new paddock every two days.

Grazing management

The team used management intensive grazing, setting up temporary electric fences to graze cattle at a high density and short duration to evenly consume forage and distribute manure while minimizing soil compaction. Hall believes grazing cover crops would allow yearling heifers to gain sufficient weight to be ready for sale by early fall, before increasing supply leads to lower prices.

His team will measure yield and forage quality of both the triticale and the cover crops.

“We have a short season, so if we put out a cover crop are we going to have enough time to get benefits as far as cattle growth?” Hall asked. “It looks like we are getting 60 to 70 days of grazing, and sometimes more, before we have to go back in with our other crop.”

In the initial year, the team planted several grasses as cover crops, and certain species in that mix produced prussic acid, which is toxic to cattle, following an early season frost. They had to suspend grazing for about two weeks amid the experiment due to the acid formation, and they’ve removed plants that could contribute to the same problem from this season’s cover crop mix, which includes peas, radishes, turnips, millet, oats, barley and rye.

Soil health and emissions

Gwinyai Chibisa, with the Department of Animal, Veterinary and Food Sciences, will record greenhouse gas emissions from cattle from this season forward, testing whether higher-quality forage from cover crops will contribute to reduced emissions. Researchers with the Department of Soil and Water Systems have equipment in the field to measure soil carbon accumulation and greenhouse gas emissions from soil.

The first two years of the project were funded by the U.S. Department of Agriculture through its Partnerships for Climate-smart Commodities Program under award # NR 2333A750004G038. Researchers are seeking additional funding for future years of the project. Researchers hope the project will inspire more producers to explore cover crop grazing as a viable strategy for improving soil health and boosting forage production in Idaho’s challenging climate.