Managing Global Resources for a Secure Future

Agriculture in Canada will be influenced by the effects of climate change with implications on environmental quality. The Alternative Cropping System (ACS) field experiment (1994-2013) at Scott, Saskatchewan, Canada, was conducted to assess the impact of agricultural inputs and cropping diversity on crop sustainability and environmental quality. Main-plot treatments consisted of three levels of agricultural inputs [organic (ORG), reduced (RED), and high (HI)] and sub-plots comprised of three levels of cropping diversity [low (LOW), diversified annual grains (DAG), and diversified annual perennial (DAP)]. This modeling study assessed soil organic carbon content (SOC), CO₂ emissions from microbial respiration (CO₂-MR), nitrate leaching, and mineralized phosphorus (P) simulated with the Environmental Policy Integrated Climate (EPIC) model for historical weather (1971-2000) and future climate scenarios (2041-2070) in the context of agricultural inputs management and cropping diversity at Scott. Variation of future projected changes in SOC, CO₂-MR, nitrate losses and P content was explored with recursive partitioning in multivariate analyses of inputs, diversity, future growing season precipitation (GSP), growing degree days (GDD) and terrain attributes (TA) at the research site. Nitrate losses, P content and CO₂-MR under future climate increased by 28, 13, and 17%, respectively, while SOC decreased by 1.3%, compared to historical values. Cropping diversity was largest factor on future nitrate losses and second largest factor on CO₂-MR and explained 22 and 5% of total variation, respectively. May GSP was main factor attributed to 21 and 16% of total variation in future mineralized P and SOC content, respectively. The remaining variation was attributed to inputs, GSP, GDD, and TA at the research site. Farming practices under RED x DAG will result in the lowest nitrate losses and CO₂-MR, and increased SOC content at study location.