Modelling Ammonia Emission from Nitrogen Fertilizer to Canadian Farmland from 1981-2016
Yang, J.Y., Drury, C., Yang, X.M. 2019. Modelling Ammonia Emission from Nitrogen Fertilizer to Canadian Farmland from 1981-2016. Poster presentation In: SSSA International Soils Meeting, San Diego California 2019/01/06 - 2019/01/09.
An ammonia emission model was developed based upon the European Environmental Agency Tier 3 modelling approach. This model was integrated into 3500 soil landscapes of Canada (SLC) polygons (1:1 M scale). Simulations of ammonia emissions by fertilizer type and crop type were performed for the period from 1981 to 2016. Data for annual nitrogen fertilizer sales for eight fertilizer types was obtained from the Canadian fertilizer industry. Fertilizer N application rates were based upon the agronomic recommendations for crops and these varied by soil type. These fertilizer N addition rates were adjusted for manure application types and rates in regions with livestock. The total fertilizer N application was harmonized with the total fertilizer N sales data at the provincial scale.
The maximum emission rates were developed from both literature and field experiments. The emission factors that reduced ammonia emission included fertilizer application rate, application methods, soil pH, temperature, and rainfall. Each year, the model calculated ammonia emission for 3000 soil polygons, and the results were scaled up to a regional, provincial and national level using a crop area weighting procedure. Ammonia emission averaged 5.3-7.6% of the total fertilizer from 1981-2016 at Canada scale, while it ranged 2-19.3% (1981) and 3-26.7% (2016) at the SLC scale, and ranged between 3-30% by fertilizer source. Urea had the highest ammonia emission rates while ammonium nitrate and anhydrous ammonia had the lowest ammonia emissions. Environmental factors that affect the ammonia emission will be discussed in this paper.