GHGMP Project Reports by Region

Don't overlook alfalfa in a crop rotation

The environmentally-friendly legume offers a productive pasture, quality hay and silage, nutrients that offset crop input costs and potential to reduce greenhouse gas emissions

Alfalfa, either as pasture or a hay stand, can provide a valuable break in annual cropping rotations, cropping systems studies in Manitoba are showing.

Weather is obviously a factor in how productive a stand can be, says Bryce Wood, with the Manitoba Zero Tillage Research Association (MZTRA). Dry conditions in southern Manitoba in 2003 had an obvious impact on the alfalfa's growth.

But, the first year of a research project at two Manitoba locations suggests the forage crop can produce a decent economic return, help improve soil quality and may contribute to lowering greenhouse gas emissions, says Wood. He's also Manitoba field co-ordinator of the federal Greenhouse Gas Mitigation Program (GHGMP). The field scale alfalfa plots are among the demonstration projects partially funded by GHGMP.

Comparing hay and pasture economics

MZTRA research compares the productivity and economics of alfalfa pasture to alfalfa hay at one site and also looks at the soil improvement benefits of alfalfa at a second location. The project, launched in 2003, is part of a long term cropping systems study comparing an annual crop rotation with a livestock based rotation.

"We want to show that alfalfa can be a valuable part of an annual cropping rotation," says Wood. "New bloat control products on the market today allow for safe grazing of alfalfa, and it can produce a good return as a hay crop too." Soil improvement benefits include nitrogen fixation, which can reduce fertilizer requirements in cereal and oilseed crops that follow alfalfa. And, as a deep-rooted legume it also helps improve water infiltration through the root zone.

"We feel it has good economics for producers, benefits soil conservation efforts and helps the environment," says Wood. "A vigorously growing perennial stand helps sequester carbon and reduces tillage over for the lifespan of the stand, which means less fuel consumption and also results in a reduced need for nitrogen fertilizer. All these factors directly or indirectly help reduce greenhouse gas emissions."

An 80-acre site on the MZTRA farm near Brandon was divided to create two 40-acre alfalfa fields. The direct-seeded stand established in 2002 was an 85 percent alfalfa and 15 percent orchard grass blend. One side was fenced and outfitted with a water system to support a 40-acre pasture for grazing, while the other field was designated for custom haying.

The pasture was custom grazed by 32 head of steers for 100 days through a rotational grazing system. The project charged 40 cents per pound for each pound of gain.

Conservative approach, dry year

It was a conservative first year, says Wood. While the project was using a new bloat control product called Alfasure, which claims to prevent bloat, site operators approached grazing cautiously. The forage blend included 15 percent grass to buffer the effect of alfalfa on bloat and the stocking rate was kept low to assess how the cattle handled alfalfa and to determine pasture carrying capacity.

"The bloat control product worked fine, there was never a concern," says Wood. "But dry conditions reduced the productivity of both pasture and hay. While there was good spring moisture to get the alfalfa growing, there was very little rain after mid-June. We never got the regrowth."

While there was adequate forage for the steers, the quality dropped over the grazing season. "Our average gain was a disappointing 1.75 pounds per day, whereas we had targeted a minimum of two pounds per day," he says. The pasture earned a gross profit of $56 per acre.

Dry weather affected productivity of the other 40-acre parcel sold as standing alfalfa hay. Total production over two cuts was only 1.75 tonnes per acre, which produced a gross return of $46 per acre.

"When we get moisture it will be a much different picture," says Wood. "The gross return figures are a bit misleading. The net figures actually show a better return per acre from standing hay because the hay didn't require the capital costs associated with fencing and the water system."

Good infiltration

In another project at the JRI Kelburn Farm in the Red River Valley south of Winnipeg, alfalfa pastures were monitored for water infiltration and then compared to continuously cropped fields. Moisture sensors called C-Probes were inserted at close intervals across alfalfa and cropped 10 and 20 acre plots at various depths ranging from four to 20 inches.

Several rainfalls over the summer ranging from about three-tenths of an inch to one and three-tenths of an inch were monitored.

"In all cases, moisture infiltration was considerably deeper on the alfalfa stand than on the continuously cropped field plots," says Wood. "It varied with the amount of rainfall, but in many cases moisture infiltration reached twice the depth on the alfalfa plots."

Similar grazing, hay and soil quality plots will be demonstrated and monitored again in 2004.

"Perennial forage stands can have a fit in previously continuous cropping rotations," says Wood. "Pasture or hayland can benefit the environment, help improve soil quality and at the same time provide economic diversification for producers."

Regional reports will be posted as information becomes available. Please check back regularly for updates.