Lowering carbon footprint of durum wheat by diversifying cropping systems

Improving cropping systems may help mitigate greenhouse gas emissions. This study determined the carbon footprint of durum wheat (Triticum turgidum L.) produced in diverse cropping systems. Durum was grown in rotation systems which had different combinations of oilseed, pulse, and cereal crops at five site-years in Saskatchewan, Canada. Total greenhouse gas emissions from the decomposition of crop residues along with various production inputs were used for the estimation of carbon footprint. On average, emissions from the decomposition of crop straw and roots accounted for 25% of the total emissions, those from the production, transportation, storage, and delivery of fertilizers and pesticides to farm gates and their applications 43%, and emissions from farming operations 32%. Durum wheat preceded by an oilseed crop (Brassica napus or Brassica juncea) the previous year had carbon footprint of 0.33 kg CO2e kg−1 of grain, or 7% lower than durum in cereal–cereal–durum system. Durum preceded by a biological N-fixing crop (Cicer arietinum chickpea, Lens culinaris lentil, or Pisum sativum pea) the previous year lowered its carbon footprint by 17% compared with durum preceded by a cereal crop. Durum produced in a pulse–pulse–durum system had carbon footprint 0.27 kg CO2e kg−1 of grain, 34% lower than durum grown in cereal–cereal–durum systems. Diversifying cropping systems with oilseeds and biological N-fixers significantly lowered carbon footprint of durum wheat.

► Strategies are needed to reduce the carbon footprint of grain products in agriculture.
► Diversifying cropping systems with oilseeds, cereals, and biological N-fixing crops significantly lowered carbon footprint of durum wheat compared with cereal-based monoculture systems.
► Durum wheat preceded by an oilseed crop (Brassica napus or Brassica juncea) the previous year had carbon footprint of 0.30 kg CO2e kg−1 of grain, or 18% lower than durum in cereal-cereal-durum system.
► Durum preceded by a biological N-fixing crop (Cicer arietinum chickpea, Lens culinaris lentil, or Pisum sativum pea) the previous year lowered its carbon footprint by 28% compared with durum preceded by a cereal crop.
► Durum produced in a pulse-based system had carbon footprint 0.24 kg CO2e kg−1 of grain, 34% lower than durum produced in cereal-cereal-durum systems.