CANB v4.0: A model for simulating Residual Soil Nitrogen and Nitrogen leaching in Canadian regional scale

摘要

A Canadian Agricultural Nitrogen Budget model (CANB v4.0) was developed to calculate two Agrienvironmental Indicators; Residual Soil Nitrogen (RSN) and the Indicator of Risk of Water Contamination by Nitrogen (IROWC-N) at 1:1M Soil Landscape of Canada scale for all Canadian farmland. The RSN (kg N ha-1) is the amount of inorganic N which remains in the soil at the end of the growing season and it is calculated as the difference between the total inputs of N and removal of N by the crop and atmospheric losses. The IROWC-N provides an estimate of the concentration and amount of the RSN which can be lost due to surface and groundwater via leaching. Both the growing season and non-growing season N leaching losses were simulated by a daily N leaching model. The outputs are displayed using EasyGrapher software and mapped using Arc-GIS software. The Ecoregion maps and graphs of the RSN, N lost and IROWCN from the CANB v4.0 model were displayed and the results were interpreted. The results indicate that there is an increasing risk of water contamination over time in Canadian farmland. The model can also be used for policy scenario analysis or integrated into a GIS framework at watershed scales.