Effects of a single cycle of tillage on long-term no-till prairie soils

Baan, C. D., Grevers, M. C. J. and Schoenau, J. J. 2009. Effects of a single cycle of tillage on long-term no-till prairie soils. Can. J. Soil Sci. 89: 521-530. A study was conducted to examine the effect of tillage on soil conditions and crop growth at three long-term (> 10 yr) no-till sites, one in each of the Brown, Black, and Gray soil zones of Saskatchewan. The four tillage treatments consisted of one cycle of tillage at three levels of intensity: spring cultivation only, fall+spring cultivation, and fall+spring+disc cultivation, all applied to no-till and also a no-till control. Total and particulate soil organic carbon, soil pH, and soil aggregation were not affected by the tillage operations. Tillage decreased the bulk density in the 5- to 10-cm soil depth, but did not affect soil water content (0-10 cm) or spring soil temperature (0-5 cm). Tillage decreased stratification of available phosphorus to some extent, but there appeared to be no associated effect on crop P uptake. Tillage did not effect crop production in any of the 3 yr following its imposition, except at one site where, in the first year, apparent tillage-induced nutrient immobilization resulted in lower yields. Overall, the imposition of one cycle of tillage on long-term no-till soils appears to have little effect on soil properties or crop growth.