Organic Production in Semi-arid Zones:
The Alternative Cropping Study at Scott, SK

Stewart Brandt, Agriculture and Agri-Food Canada, Scott, SK

The Alternative Cropping Study was initiated in 1994 in the moist mixed grassland region of Saskatchewan. Rotational cycles last for 6 years and include a low diversity wheat based system, a diverse annual grain system and a diverse system including perennials (though establishment of perennial and biennial crops has been problematic). Each rotation is run under organic, high input, and reduced input conditions.

Yields in organic systems were lower than in the other systems. Water was the major yield driver between years. Many of the recent years have had markedly reduced precipitation. Supply of nitrogen and the degree of weed competition were important yield determinants. Weed levels in organic plots compared with those in high input plots were higher in some years, such as 1998, but lower in other years, such as 2000. Green manure one year in three may not provide sufficient nitrogen to meet crop needs. More recently, available phosphorus levels may be important.

Economic analysis indicated that net returns for the "complete system" were highest for the organic system if organic premiums were achieved for 50% or more of the crops. Organic systems also had the greatest energy efficiency.

Nitrogen balance was positive if a legume was seeded one year in two, but not one year in three. Phosphorous levels were of concern, showing a consistently negative balance. Erosion potential, as measured as the proportion of land not covered by residues, was highest in the organic system in 2003, as most residues were eaten by grasshoppers.


Source
1st Canadian Organic Agriculture Research Workshop, University of Guelph, January 2004


Contact Info
Stewart Brandt, Scott Research Farm, Highway 374, P.O. Box 10
Scott, Saskatchewan S0K 4A0 CANADA
Email: brandts@agr.gc.ca


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