One last report from the Alberta agency that spearheaded reduced-tillage farming in the province summarizes the benefits and costs for farmers seen during the move to no-till.

Alberta Reduced Tillage Linkages (RTL), which shut down its operations at the end of August, says in a release that the report is "one of the legacies left behind" by the agency, which started in 1994 as the Alberta Reduced Tillage Initiative and rebranded as RTL in 2000.

The report, by Edmonton consultant Mirza Baig and RTL leader Peter Gamache, was meant "to summarize all the economic, agronomic and environmental benefits of no-till in Western Canada with special emphasis on Alberta."

A secondary objective, Baig says, "was to identify gaps in our current knowledge about no-till in Alberta, and apply information from elsewhere in North America to fill these gaps."

RTL notes that no-till acres in the province rose from 600,000 in 1991 to 9 million by 2006.

On average, Baig and Gamache found crop yields "generally higher" in no-till systems, with wheat yields up 3.5%, barley 6.2%, flax 7.9%, peas 4.6% and lentils 13%.

Labor cost was also "considerably" lower, the report notes, with zero-till requiring 3.5 passes on average in a field compared to 5.8 for minimum-till and 7.5 for conventional tillage.

The report also points to a "significant reduction" in fuel consumption. Wheat crops seeded into stubble required 19.9 litres of fuel per hectare, compared to 30.2 under a conventional-tillage system.

The RTL paper notes "conflicting reports on the relative use and cost of herbicides across tillage systems" on the Prairies, including an Alberta Agriculture study showing no difference in herbicide cost between no-till and conventional-tillage systems, and a cropping practices survey in Saskatchewan finding herbicide costs for reduced tillage "slightly higher than for conventional tillage."

Generally, the report says, production costs for no-till are lower as compared to those for conventional tillage, but the differences vary between soil zones.

For example, the report notes, in the brown soil zones of Alberta and Saskatchewan, reduced-tillage systems are less profitable, especially in continuous cereal and cereal-fallow rotations, but in dark brown soil zones, no-till is "equal to or marginally more profitable" than conventional tillage.

In the Prairies' black and gray soil zones, however, "no-till and minimum tillage are superior to conventional tillage," the report says, citing "higher grain yields and better cost of production" for zero-till.

Soil conservation with reduced tillage has reduced the risk of soil erosion to only a "small proportion" of farmland, the report notes, citing less than 14% of acres susceptible to water erosion and 30% to wind erosion.

No-till also increases water infiltration into the soil, reduces sediment and pesticide losses that would otherwise enter the watershed, and may reduce phosphorus and nitrogen loss, the report says.

The report also notes the commonly accepted principle that land converted to no-till sequesters atmospheric carbon dioxide into the soil, reducing greenhouse gases and enhancing soils as a "carbon sink."

In terms of wildlife habitat, studies in Canada and the United States have also pointed to no-till farming, especially in fall-seeded winter cereals, as producing "greater abundance and diversity of songbirds, ducks, small mammals and soil arthropods."

Adoption of no-till has an impact on weeds, diseases and insect species' diversity and numbers, the report notes, finding broadleaf weeds decrease in no-till, although some grassy weeds and perennial weeds increase.

"Studies in Alberta and Saskatchewan have shown that year-to-year variation in climatic conditions and crop rotations have a greater impact on weeds than tillage systems," the report notes.

Baig and Gamache also note "conflicting reports" on the incidence and severity of plant diseases in minimum and no-till systems, with some earlier studies showing increased incidence and severity of disease levels in conservation tillage, while other studies "showed a decrease or no effect."

Insect pests also respond differently to tillage practices, the report notes, as populations of some species increase under minimum and no-till while others decrease.