Low input and organic cropping systems for semi-arid regions.

R. E. Blackshaw and M. J. Clapperton

Abstract
Long-term studies are required to develop more sustainable dryland cropping systems. A planned 12-year study cooperatively designed by scientists and farmers was initiated in 1997 at Lethbridge, AB.

The study objective is to identify agronomic practices that reduce input costs and increase grower net returns, improve management of weeds and pests, and improve soil quality.

Production practices investigated include compost manure, green manure crops, intercropping, and greater use of forages with conservation tillage employed whenever possible. Rotations vary from simple two-year to complex four-year crop sequences. Organic cropping systems are explored in three of seven rotations within the study.

Preliminary results indicate that sweetclover underseeded in wheat and then treated as a green manure crop in year two effectively controlled weeds, provided sufficient biomass to reduce erosion and build organic matter, and supplied 16 to 56 kg ha^-1 available nitrogen for the succeeding crop. Compost manure was capable of meeting a significant portion of the crop's nutrient demand. Intercropped barley and peas suppressed weeds well and produced high quality silage. The success of underseeded forages for fall grazing was highly dependent on late summer and fall rainfall with production being minimal in drought years.

A sustainable farming workshop featuring this study has been held every second year with excellent grower interest.


Author Locations and Affiliations
Agriculture and Agri-Food Canada Research Centre, Lethbridge, Alberta, Canada T1J 4B1.
Corresponding author: blackshaw@agr.gc.ca


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