Evaluating Cover Crop Mixtures For Higher And Lower Rainfall Areas In Alberta

M. J. Clapperton¹, M. Kalischuk², D. Spaner³ and G. Durr²

Cover crops are regularly used by organic farmers as green manures and tilled into the soil to increase organic matter and fertility. Tillage, however, destroys the structure of the soil habitat reducing the population and diversity of soil biota that are essential for enhanced soil biological fertility.

Our aim in designing this 3-year field study was to: reduce tillage and the use of mono culture cover crops, increase above and below-ground diversity, and enhance soil nutrient cycling, while allowing for the flexibility of grazing.

Thus, we investigated the establishment and growth of plant mixtures (containing 2-3 species) for cover crops that are competitive with weeds, can be used to supplement late or early season grazing, and create root canopies to promote soil biological activity and habitat stability.

In this poster we report on the results from the first year and the results to date from the second year of this field study. In 2003, 13 mixtures of plant species were seeded into small plots in a randomised block design in 2 different rainfall zones: Lethbridge which is semi-arid grassland, and Edmonton which is parkland.

The results demonstrated the differing growth potential of the mixtures, and in particular the legumes, between precipitation zones. The legumes that established and performed well within the mixtures at both locations were: woolypod vetch, chickling vetch, subterranean clover and black lentil.

There were significant differences in the concentrations of various micronutrients between the individual mixtures and the sites. The following year at both field sites the chicory in two of the mixtures regrew and completely out-competed the wheat. Otherwise, there were no significant effects of the previous cover crops on wheat yields at either field site.

See this poster in PDF format


Source
2nd OACC Organic Research Workshop, Presented in association with the Organic Connections: Prairie Wide Organic Conference and Trade Show, November 14-16th, 2004


Author Locations and Affiliations
(1) Agriculture and Agri-Food Canada, Lethbridge AB,
(2) Organic Agriculture Centre of Canada,
(3) University of Alberta, Edmonton, AB.
Correspondence: lapperton@agr.gc.ca