Modelling nitrogen leaching in Prince Edward Island under climate change scenarios

Projected climate change in Canada and its impact on crop yield and production have been studied, but the impacts on soil and water quality are less well known. The objective of this study was to model and evaluate the potential impacts of climate change on soil nitrogen (N) leaching in Prince Edward Island. Residual soil nitrogen (RSN), the quantity of inorganic soil N at the time of harvest, was calculated from an annual N budget, based on Census of Agriculture data. RSN was added to the soil in the fall and subject to leaching until the start of the next growing season. Water and N movement in and through the soil were calculated with a modified version of the Versatile Soil Moisture Budget. The provincial averages of RSN and N leaching under historic (1971-2000) climate and management conditions were calculated to be 30.8 kg N ha(-1) and 27.9 kg N ha(-1), i.e., 91% of the RSN was lost via leaching. With no changes in agricultural practices, N leaching under four climate change (2040-2069) scenarios remained very similar (+/- 1%) to that simulated under historic climatic conditions. With agricultural intensification, in response to climate change and economic conditions, RSN levels increased to 35.7 kg N ha(-1) and estimates of soil N leaching increased by 5 to 30% beyond historic levels.