In real estate it’s “location, location, location.” In organic agriculture, it’s “rotation, rotation, rotation,” says 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, Man.
At Carman, Entz has established a six-phase rotation with green manure every third year. Cropping phases include oilseed, pulse and cereal crops.
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 green manure in fall. Next in the rotation is flax, followed by oats.
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Chickling vetch is a second green manure, and is followed by a late August seeded oilseed radish to build soil. The final two crops in the rotation are wheat and soybeans.
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 of the green manure, the following flax is likely to face less weed pressure.
Weeds that build up in the flax year will face strong competition from 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. Soybeans can use any residual nitrogen, or supplement with its own nitrogen production if soil levels run low.
The Organic Crops Field Lab has already proven to be an excellent teaching and extension location. In 2006, the site was used to introduce more than 300 agronomists at the Crop Diagnostic School to the principles of organic agronomy. Graduate and undergraduate students train at the site and it is accessible to various field days and tours.
The Organic Crops Field Lab is primarily for research. Each of the rotational phases occupies an acre and a half, allowing ample room for small plot experiments or for midsized 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.
Entz has used the Carman facility for a number of studies, including an evaluation of green manures for their ability to take up phosphorus. He found that legumes such as faba beans and berseem clover, and non-legumes such as oats 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 careful management is necessary to avoid reducing soybeans as well.
Jackie Pridham, a graduate student working with Entz, has conducted 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 Canada are using the organic research facility. Wheat breeder Stephen Fox is 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, the Organic Crops Field Laboratory is a strong source for organic research.
Frick is the prairie co-ordinator for the Organic Agriculture Centre of Canada located at the University of Saskatchewan. She can be reached at 306-966-4975, at brenda.frick@usask.ca, or www.organicagcentre.ca.
