Grant: Alliance Grants

Climate change is creating opportunities for agricultural expansion in northern regions, which will demand the conversion of forest and scrub-brush to productive fields. Historically conversion has resulted in losses to the "bank" of soil organic matter of up to 50% because of lower returns of organic matter to the soil and conditions that favor decomposition of existing stores. These losses presumably erode soil health because of the key role organic matter plays in determining the physical, chemical and biological properties of the soil, the heart of its well-being. Leaving woody biomass on-site through the process of mulching and subsoiling could mitigate these losses, while being the most rapid and potentially cost-effective method for land conversion, but there are knowledge gaps that beg for the proposed research. Significant declines in yield in the second year after mulching have required the application of large amounts of fertilizer, the longer term benefits of leaving organic matter on-site have not been studied, and it is unknown if established indicators of soil health e.g. Cornell Soil Health Assessment (CSHA) are applicable in more northern climates. This project will address these gaps by: 1. examining the longer term effects of land conversion on soil health and soil organic matter and identifying the best indicators for monitoring change in soil health in Northern Ontario through measurements and comparisons of indicators of soil health on farms that have mulched and cleared conventionally in Northern Ontario, 2. establishing a field trial to examine the effects of woody residue incorporation (timing and placement), rate of fertilizer application, and rotation strategy on yields of oats and barley, two key grain crops in Northern Ontario, soil health and soil organic matter stores, and 3. determining the profit margins of land clearing practices to identify the most effective, economical and sustainable approach for Ontario's grain farmers.