Climate Change and Dryland Agricultural Ecosystem Management

Developing low-carbon-footprint cropping systems for semiarid
areas
Yantai Gan1,*, Chang Liang2, Chantal Hamel1, Herb Cutforth1 and Hong Wang1
1Agriculture and Agri-Food Canada, Semiarid Prairie Agricultural Research Centre, Swift Current, Saskatchewan, S9H
3X2, Canada; 2Environment Canada, Greenhouse Gas Emission Division, 19th floor, 351 Blvd St-Joseph, Gatineau,
Québec K1A 0H3, Canada;
Abstract:Carbon footprint is defined as the amount of greenhouse gas emissions associated with a
product or a service, expressed in carbon dioxide equivalence (CO2e). There is an increasing demand
for carbon footprint labeling of farm products. This paper compared carbon footprints of seven field
crops grown on the semiarid Canadian Prairies and determined the carbon footprint of a durum wheat
grown in various cropping systems. The values of carbon footprints were estimated based on
emissions from the decomposition of crop straw, roots and seeds; the manufacture of N and P
fertilizers and their application; the production of herbicides and fungicides; and miscellaneous farm
field operations including planting, tillage, spray of pesticides, and harvest of the crops. Carbon
footprint calculations showed that the production and application of N fertilizers accounted for about
57 to 65% of the total footprints, those from crop residue decomposition 16 to 30%, and the rest of the
carbon footprints were associated with P fertilizers, pesticides, and field operations. One kg of crop
product requires 0.7 kg CO2e for canola (Brassica napus L.), 0.4~0.6 kg CO2e for mustard (Brassica
juncea L.), flaxseed (Linum usitatissimum L.), and spring wheat (Triticum aestivum L.), and
0.17~0.26 kg CO2e for chickpea (Cicer arietinum L.), lentil (Lens culinaris), and dry pea (Pisum
sativum L.). Durum crop preceded by a pulse crop produced grains with a carbon footprint of 673 kg
CO2e, 20% lower than when the crop was preceded by a cereal crop. Similarly, carbon footprint of
durum preceded by an oilseed was 744 kg CO2e, 11% lower than when after a cereal. Carbon
footprint intensity was 0.25 and 0.28 kg CO2e per kg of the grain of durum grown, respectively, after
a pulse and oilseed crop, which was signif6icantly lower than 0.37 for the crop grown after a cereal.
Carbon footprint of field crops grown in semiarid areas can be significantly influenced by crop
choices and crop sequences. The values of footprints can be reduced by adapting improved cultural
strategies, including (i) diversifying cropping systems and minimizing monoculture; (ii) including
annual pulse crops to reduce the input of synthetic N fertilizers; (iii) improving nutrient use efficiency
through use of biotechnologies valorizing soil microbial resources; (iv) adopting direct-seeding
technology to reduce energy input in crop production; and (v) improving crop residue management for
maximizing carbon sequestration.
* Corresponding author: Yantai Gan, Email: yantai.gan@agr.gc.ca
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