Organic Connections Conference 2006 - Research Poster Winners' Abstracts

First Prize: Is organic spring wheat breeding necessary?
Second Prize: Can Annual Intercrops Help Control Weeds and Improve Productivity?
Third Prize: Can cultivar choice and seeding rate increase competitive ability in organic spring cereals?

 

First prize: Is organic spring wheat breeding necessary?

Reid, T. A., A. Navabi, D. Spaner
University of Alberta, Edmonton AB

Abstract
Organic wheat producers in western Canada mainly use cultivars which have been bred under conventional management systems or use older cultivars released before the wide spread use of chemical fertilizers and pesticides.

We are conducting experimentation to investigate whether breeding populations selected in later generations would differ between conventional and organic management systems.

A population of 79 F6 recombinant inbred lines derived from a cross between AC Barrie and Attila was grown with replication and eleven check cultivars at two Edmonton AB sites (one organic) in 2005 and six sites (three organic) throughout central AB in 2006.

Preliminary results (employing only grain yield as the primary selection criteria) suggest the top 10% yielding lines differ between conventional and organic sites.

Thus, selecting high yielding lines under conventional management may not provide the highest yielding under organic management. These preliminary results may suggest that the selection of “organic cultivars” may be possible under organic management.

 

Second prize: Can Annual Intercrops Help Control Weeds and Improve Productivity?

A.G. Nelson¹, S. Quideau², B. Frick³, Jill Clapperton⁴ and D. Spaner¹

1 Department of Agricultural, Food and Nutritional Sciences, University of Alberta, 2 Department of Renewable Resources, University of Alberta, Edmonton, AB,
3 Organic Agriculture Centre of Canada at University of Saskatchewan,
4 Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1

Abstract
Weed control and low productivity continue to be issues in organic cropping systems.

We examined the use of annual intercrops for weed suppression and yield stabilization at four field sites in 2006. Monocrops of wheat, barley, canola (Brassica napus) and field peas, and all intercrop combinations that include wheat were grown in two conventional and two organic locations in Edmonton, and New Norway, AB. Recommended seeding rates were used, and adjusted according to the number of crops in the mixture.

Ability to compete as well as yields and land equivalent ratios (LER) were determined using biomass and yield samples.

In both organic and conventional systems, the barley monocrop and intercrops that included barley had significantly less weed biomass than other treatments. Yields in the conventional systems were higher than in the organic systems

However, some intercrops were found to improve overall productivity in both systems of production. The intercrop treatments wheat:canola, wheat:barley:canola, wheat:barley:peas and wheat:barley:canola:peashad mean LER’s significantly higher than one. LER’s greater than one mean indicate that more monocropped land would be needed to achieve the intercrop yield. The intercrop treatments had similar LER’s in both the organic and conventional systems.

Intercropping less competitive crops with a competitive crop like barley can improve weed suppression and productivity above that of monocrops. We will be examining the soil biology of intercropped systems in future studies.

Third prize: Can cultivar choice and seeding rate increase competitive ability in organic spring cereals?

H. Mason¹, A. Navabi¹, B. Frick², J. O’Donovan³ and D. Spaner¹

1Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB
2Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK
3Agriculture and Agri-Food Canada, Beaverlodge, Alberta

Abstract
Organically managed production systems often experience greater weed pressure than their conventional counterparts, potentially causing yield losses and increased weed seed build up. The use of competitive crop cultivars and the cultural practice of increasing seeding rates may moderate such production constraints.

Field trials were conducted at two organically managed locations in Alberta, Canada for two years to determine the effect of cultivar and seeding rate (300 and 600 seeds m-2) on the competitive ability and agronomic performance of Canadian spring wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). Cultivars were selected based on their differing heights, tillering capacities and times to maturity.

Competition from tame oats reduced grain yield by an average of 26%. Barley cultivars were generally more competitive than wheat cultivars. Height, early maturity and early season vigour were more closely associated with weed suppression and yield maintenance than tillering capacity.

The modern semidwarf CDC Go was the highest yielding wheat cultivar, but was a poor weed suppressor; the older and taller cultivars, Katepwa and Park, combined the highest yield with the greatest weed suppression.

Doubling the seeding rate increased grain yield, weed suppression and economic returns. This effect was not cultivar specific, which implies that doubling the seeding rate may be a generally effective method of overcoming yield losses and weed seed build up associated with increased weed populations under organic production.