Dr. Gabriel Maltais-Landry – Optimizing the use of organic amendments and cover crops to maximize agronomic and environmental benefits

Gabriel Maltais-Landry is a postdoctoral fellow at UBC ‘s Faculty of Land and Food Systems. He works primarily with the Sustainable Agricultural Landscapes Lab and Centre for Sustainable Food Systems. Dr. Maltais-Landry’s talk will focus on how optimal nutrient management is a critical aspect of sustainable farming systems, where nitrogen (N) and phosphorous (P) must be supplied in sufficient quantities to maximize crop yields and maintain soil fertility while preventing over-fertilization that results in environmental degradation. Organic amendments – manures and composts – and cover crops recycle N and P within farming systems, reducing the use of mineral fertilizers while potentially lowering nutrient losses to surrounding ecosystems. The aim of Gabriel’s research is to optimize the user f organic amendments and cover crops to maximize yields and balance eN and P budgets in intense agroecosystems. Using several experiments established at the UBC Farm, several trade-offs were identified among crop productivity, balanced N and P budgets, and greenhouse gas emissions (GHG), where treatments with the highest yields resulted in N and P over-fertilization and higher GHG emissions. In addition, there was little evidence that cover crops prevented wintertime N leaching from occurring, although cover crops contributed to N cycling nevertheless. Overall, my research highlights the inherent challenges in balancing N and P while maintaining high yields when using organic amendments and cover crops as primary sources of fertility in intensive vegetable farming systems.