Assess the agronomic suitability and pest management benefits of 1) an accelerated (3 crops in 2 years) cropping system. 2) an accelerated relay inter-cropping system.
Innovative cropping systems are required for yield and economic stability and to manage pests and improve ecosystem functioning. The potential risks and benefits of Accelerated Crop Production Systems (ACS), the production of three crops in two growing seasons using a combination of spring and winter crops, were evaluated in two experiments. The first experiment consisted of seeding a winter cereal (triticale, fall rye) in alternate rows with spring wheat in the first year, and the winter cereal was cut for silage in the second year, followed by the seeding and harvesting of an early maturing crop (barley, Polish canola, Argentine canola or field pea). The second experiment consisted of seeding a winter cereal (triticale, open-pollinated and hybrid fall rye) in alternate rows with spring wheat, similar to the first experiment. The winter cereals were allowed to form an intercrop in the second year. The second-year spring crop and winter cereal crop were harvested for grain. Both experiments completed three crop cycles at Kernen and Goodale sites at Saskatoon SK and additionally, the second experiment completed one cycle at Scott, SK. Results from the ACS experiment revealed that the three-crop system with winter cereals caused a reduction in second-year crop biomass depending on the crop (barley -86% , pea-53%, Polish canola -32%, Argentine canola – <1%). Among the four crops, barley had significantly low weed biomass than the other crops independent of the first-year crop. Contrasts within and across crops revealed that weed biomass was similar between systems that had wheat monoculture and wheat intercrops with winter cereals in the previous year. Among all second-year crops, the rotations that had wheat +WT in the first year had a low wild oat density (32%) compared to wheat in the first year. Barley, pea and Polish canola grain yields were greater when followed by wheat monocrop compared to wheat + winter cereal intercrop. However, there was no difference in grain yield in Argentine canola depending on the first-year crop. The results from the AIC trial revealed that crop biomass in the second year varied among sites. When averaged across sites, cop biomass found to be similar between second year monocrop systems and average of all intercrop systems within crops and across all crops. In canola, there were no differences in weed biomass depending on the first-year crop. However, weed biomass in pea was significantly low in the rotation with spring wheat monoculture in the first year compared to all other intercrop systems. Among canola systems, second-year total crop yield was significantly greater in canola proceeding SW+ FR(OP) compared to the canola monoculture (SW-canola rotation). There was no difference in crop yield among pea-based systems depending on the first year crops. Overall, this study revealed that none of these accelerated cropping systems had a significant overall weed management advantage over the two-crop system other than for wild oat management. However, canola-based intercrop systems had similar weed management to canola monocrop system with herbicides. The three-crop intercrop system can be more beneficial for the canola-based rotations as it can enhance the overall productivity and can reduce the use of herbicides and achieve similar weed control to the two-crop system with standard herbicides. Still, this comes with an income penalty as the net revenue was always better in the two-crop system.