Cropping system typologies perform differently under climate stress in Manitoba, Canada: multi-criteria assessment

Abstract

Information is required to understand how novel biodiversity strategies can improve cropping system resilience to climate change. A “business as usual” (BAU) rotation (wheat-canola-wheat-soybean) was compared with a “warm-season crop” (WS) rotation (corn-sunflower-dry bean-canola); a “biodiverse” (BD) rotation (fall rye with cover crop- corn/soybean intercrop - pea/canola intercrop- green fallow mixture); a “perennial grain” (Kernza) rotation (Kernza grain intermediate wheatgrass); and an organic (ORG) rotation (millet-green fallow mixture-wheat). Drought conditions prevailed in both study years. The BAU rotation had the lowest average yield (1821 kg ha-1 compared with 2533 and 3083 kg ha-1 for the BD and WS rotations, respectively), less post-harvest residual biomass and a lower net return than the WS rotation. The WS rotation was limited by herbicide resistant weeds in dry beans. Kernza seed yield was five times lower than for spring wheat. ORG wheat yielded the same as other wheat and had a higher net return. Live roots days, a measure of soil health potential, were 95 for the BAU rotation, and 174 and 113 for the BD and WS rotations, respectively; the most were recorded for Kernza (365). Seasonal crop growth duration was increased by including Kernza and fall rye for early season growth, and corn, sunflower, a corn-soybean intercrop, a cover crop and fall seeded rye for late season growth. WS and BD rotations outperformed the BAU rotation and the BD system accomplished this with half the N fertilizer. Results demonstrate the potential of biodiverse rotations; barriers to their adoption should be addressed.