Soil Conservation

The soils of Saskatchewan are fragile, and tillage operations have contributed largely to some of the environmental problems facing agriculture. For a century, Saskatchewan farmers used Summerfallow as a means to control Weeds and conserve moisture; this practice, however, led to soil erosion and the loss of soil nutrients. Producers have changed the manner in which they manage soil resources and moved to a lesser disturbance of soil: conservation tillage. In 1980 there were 7 million ha of fallow land, but this had declined to only 3.4 million ha by 2000; it now represents only 13% of Saskatchewan's agricultural land base. Summerfallowing is more frequent in the Brown Soil Zone and less in the Black Soil Zone, where soil moisture is more plentiful.

Increasingly farmers have adopted Conservation tillage practices: this means less tillage that tends to leave more of the previous crop residue on the soil surface after planting. Tillage systems can be classified into three types: conventional tillage, minimum tillage, and zero tillage. The latter two systems are generally referred to as “conservation tillage,” incorporating most of the crop residue into the soil, thus making the soil less susceptible to wind and water erosion. With zero tillage there is no tillage done prior to seeding. Many farmers who tend to follow conservation tillage by including summerfallow in their rotation no longer till the soil, but instead apply chemicals to kill weed growth; this practice is referred to as chem-fallow. Zero tillage or direct seeding has gained popularity. Because of the higher incidence of weeds, higher application of herbicides is required. In the census year 2001, 13,248 farms reported some use of zero till and/or direct seeding. These farmers constituted 30% of the total producers in the province in that year. Also, 5.46 million ha were under zero tillage, representing 38.7% of the total area prepared for seeding during that year. Much of this area tended to be concentrated in the Dark Brown and Black Soil zones.

Interest in conservation tillage methods is thus increasing for economic and environmental motives. Progress made during the last decade is shown in Figure SC-1. In 1990, almost two-thirds of the total area prepared for seeding was done using conventional tillage systems; only 10% of the total was under zero tillage. By 2000, this had increased over threefold to 5.46 million ha.

Conservation tillage methods require fewer field operations, resulting in less Labour and energy use by farmers. The reduced use of fossil fuels reduces emissions of carbon dioxide. The correspondingly higher use of herbicides for weed control leads to higher incidence of pathogens and insects. More fertilizer is required, which means higher energy use to manufacture the fertilizer.

Through direct seeding and minimum and zero till, as well as seeding permanent cover crops and maintaining native grasslands, carbon sinks are created by plants which remove carbon from the air and store it in the soil. On account of adoption of zero tillage, which increases soil organic matter, Saskatchewan producers have been able to decrease emissions of carbon dioxide into the atmosphere by 3.83 million tonnes. These carbon stocks in the Soils are known as “carbon offsets,” and have been recognized as a means for Canada to meet its targets for reduction of greenhouse gas emissions. Saskatchewan farmers are becoming more environmentally conscious, having reduced summerfallow in their crop rotations and having adopted reduced tillage practices. This has led to a more sustainable agriculture. In 1987 the Saskatchewan Soil Conservation Association (SCCA) was formed “to promote conservation production systems to improve land for future generations.” The organization promotes the use of minimum and zero tillage operations; it also serves to represent farmers' interests at the governmental level on issues relating to soil conservation and the Kyoto Agreement.

Gary Storey, Suren Kulshreshtha

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Further Reading

Kulshreshtha, S.N., and G. Storey. 1999. “Soil Conservation Practices.” In Atlas of Saskatchewan. Saskatoon: University of Saskatchewan.