ECONOMICS OF TILLAGE SYSTEMS FOR SPRING WHEAT PRODUCTION IN SOUTHWESTERN SASKATCHEWAN (CANADA)

The economic performance of continuous wheat (Triticum aestivum L.) and fallow-wheat rotations grown under conventional, minimum- and zero-tillage management practices on silt loam, sandy loam and heavy clay in southwestern Saskatchewan was determined during the relatively dry period of 1982-1988. The costs and returns for each rotation-tillage system were evaluated annually based on 1989-90 price and cost conditions, and for various other plausible scenarios. Gross returns on silt loam were higher for continuous wheat (average 228 $ ha-1) than for fallow-wheat systems (average 155 $ ha-1). On the sandy loam, gross returns were similar for all cropping systems (average 112 $ ha-1); on the heavy clay, they were higher for fallow-wheat than for continuous wheat (139 versus 119 $ ha-1). Conservation tillage management increased gross returns over that obtained with conventional tillage only in years when growing season temperatures were high and precipitation was poorly distributed, or when the 21-month summerfallow period was droughty. On silt loam, gross returns were significantly lower with conservation tillage in as many as 3 of 7 years. On silt loam, net returns were highest for conventionally tilled continuous wheat when wheat prices were > 175 $ t-1; at lower wheat prices, conventionally tilled fallow-wheat was the most profitable. On the other soils, minimum- and zero-tillage fallow-wheat provided the highest net returns at all wheat prices tested, with minimum tillage being slightly better at low wheat prices, but at these sites conventionally tilled fallow-wheat was not studied. The cost of production was highest for continuous wheat and for zero-tillage management. For fallow-wheat systems, conservation tillage required lower expenditures than conventional tillage for fuel, labor, machine repair and machine overheads; costs for minimum tillage averaged 9 $ ha-1 and for zero tillage 15 $ ha-1 lower on the silt loam. These savings were more than offset by increased herbicide costs which averaged 26 and 64 $ ha-1 higher for minimum-tillage and zero-tillage systems, respectively. We concluded that producers in southwestern Saskatchewan who are motivated primarily by short-term profit will find little incentive to adopt conservation tillage systems for spring wheat production, unless they are situated on soils that have already incurred severe soil loss or the soils are highly prone to further erosion losses.