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By Brenda Frick, Ph.D., P.Ag.
“In real estate it’s ‘location, location, location’. In organic agriculture it’s ‘rotation, rotation, rotation’. ” So proclaims University of Manitoba researcher Martin Entz. To be credible, organic research needs to be conducted as part of a valid organic rotation. To meet this requirement, Entz has developed the Organic Crops Field Laboratory at Carman, Manitoba.
At Carman, Entz has established a six-phase rotation with a green manure every third year. Cropping phases include oilseed, pulse and cereal crops. Currently Entz starts his rotation with a berseem clover and alfalfa mix. The first growth is cut for hay in mid summer, and the regrowth is incorporated into the soil as a green manure in fall. Next in the rotation is flax, followed by oats. Chickling vetch is a second green manure, and is followed by a late August seeded oilseed radish in order to build and retain soil. The final two crops in the rotation are wheat and then soybean.
This rotation offers many advantages. The first green manure includes
a forage option for mixed farms, or for income. With a mid summer cut
and fall incorporation in the green manure, the following flax is likely
to face a drastically reduced weed pressure. Weeds that build up in
the flax year will face strong competition in the oats. Flax is not
a heavy feeder, but after the oat crop, nitrogen levels may be running
low. This is addressed in the second green manure. Wheat is placed in
the rotation to take advantage of the nitrogen boost of the green manure,
improving its likelihood of reaching high protein levels. Soybean can
use any residual nitrogen, or supplement with its own nitrogen production
if soil levels run low.
The Organic Crops Field Lab is primarily a research opportunity. Each of the rotational phases occupies an acre and a half, allowing ample room for small plot experiments or for midsize field equipment. Each phase is present each year. This allows someone interested in oat research, for example, to establish oat plots at the same stage in a valid organic rotation, year after year for a long term study. This is an invaluable asset for researchers interested in organic agronomy. Keith Barmford, University of Manitoba technician, maintains the field, providing the organic management so researchers are free to focus on their specific concerns.
Entz has used the Carman facility for a number of studies, including an evaluation or green manures for their ability to take up phosphorus. He found that both legumes such as faba bean and berseem clover and non-legumes such as oat and mustard made valuable green manures, aiding in the cycling of both nitrogen and phosphorus. Entz also tested fall rye to suppress weeds in soybeans. Initial results suggest that fall rye can suppress weeds, but may careful management is necessary to avoid reducing soybean as well.
Jackie Pridham, a graduate student working with Entz has conducted prize winning research at this site on crop diversity. Pridham compared the usual practice of seeding a single variety in a field to using mixtures of varieties of wheat, mixtures of cereal crops and mixtures of cereals with other types of crops.
She found that mixtures can produce higher yields, can increase profitability and allow for a more stable yield.
Researchers from Agriculture and Agri-Food Canada are using the organic research facility. Wheat breeder Stephen Fox is now growing the fifth generation of plants bred under organic conditions. Fred Townley-Smith and Jennifer Mitchell Fetch are using bulk breeding methods at the Carman facility to produce oats especially suited to organic production.
By establishing a facility with a long term meaningful organic rotation, and by making this available to researchers as they need it, Entz is growing organic research potential. The Organic Crops Field Laboratory is a strong model for organic research.
More information on the Organic
Crops Field Laboratory
© 2012, Organic Agriculture Centre of Canada (OACC)