title: Impact of management strategies on the global warming potential at the cropping system level.
abstract: Estimating the greenhouse gas (GHG) emissions from agricultural systems is important in order to assess the impact of agriculture on climate change. In this study experimental data supplemented with results from a biophysical model (DNDC) were combined with life cycle assessment (LCA) to investigate the impact of management strategies on global warming potential of long-term cropping systems at two locations (Breton and Ellerslie) in Alberta, Canada. The aim was to estimate the difference in global warming potential (GWP) of cropping systems due to N fertilizer reduction and residue removal. Reducing the nitrogen fertilizer rate from 75 to 50 kg N ha(-1) decreased on average the emissions of N2O by 39%, NO by 59% and ammonia volatilisation by 57%. No clear trend for soil CO2 emissions was determined among cropping systems. When evaluated on a per hectare basis, cropping systems with residue removal required 6% more energy and had a little change in GWP. Conversely, when evaluated on the basis of gigajoules of harvestable biomass, residue removal resulted in 28% less energy requirement and 33% lower GWP. Reducing nitrogen fertilizer rate resulted in 18% less GWP on average for both functional units at Breton and 39% less GWP at Ellerslie. Nitrous oxide emissions contributed on average 67% to the overall GWP per ha. This study demonstrated that small changes in N fertilizer have a minimal impact on the productivity of the cropping systems but can still have a substantial environmental impact.
authors.affiliation: Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, K.W. Neatby Building, Ottawa, Ontario K1A 0C6, Canada.
authors.forename: Pietro
authors.initials: P
authors.lastname: Goglio
authors.affiliation: Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, K.W. Neatby Building, Ottawa, Ontario K1A 0C6, Canada.
authors.forename: Brian B
authors.initials: BB
authors.lastname: Grant
authors.affiliation: Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, K.W. Neatby Building, Ottawa, Ontario K1A 0C6, Canada.
authors.forename: Ward N
authors.initials: WN
authors.lastname: Smith
authors.affiliation: Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, K.W. Neatby Building, Ottawa, Ontario K1A 0C6, Canada. Electronic address: ray.desjardins@agr.gc.ca.
authors.forename: Raymond L
authors.initials: RL
authors.lastname: Desjardins
authors.affiliation: Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, K.W. Neatby Building, Ottawa, Ontario K1A 0C6, Canada.
authors.forename: Devon E
authors.initials: DE
authors.lastname: Worth
authors.affiliation: Swift Current Research Station, Swift Current, Saskatchewan S0E 1A0, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Zentner
authors.affiliation: Melfort Research Farm, PO Box 1240, Melfort, Saskatchewan S0E 1A0, Canada.
authors.forename: Sukhdev S
authors.initials: SS
authors.lastname: Malhi
mesh_terms: D000383:Agriculture / Q000379:methods*; D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control* / Q000706:statistics & numerical data; D057231:Climate Change; D018556:Crops, Agricultural / Q000254:growth & development; D005308:Fertilizers / Q000032:analysis / Q000706:statistics & numerical data*; D057232:Global Warming; D017752:Greenhouse Effect
chemical_list: D005308:Fertilizers
keywords: Crop management; Cropping systems; DNDC; Energy demand; GWP; LCA