The potential of agroforestry to reduce atmospheric greenhouse gases in Canada: Insight from pairwise comparisons with traditional agriculture, data gaps and future research

Abstract

Canadian agriculture is a source of greenhouse gases (GHG) and agroforestry has the potential to sequester carbon (C), and mitigate agricultural GHG emissions. Agroforestry systems are common features in Canada's agricultural landscape; however, there are limited empirical data to support implementation of agroforestry practices for GHG mitigation. This shortfall of data may be a contributing factor to the lack of policy that supports the use of agroforestry for GHG mitigation in the Canadian agricultural landscape. We reviewed published studies that compared C stocks in vegetation and soils, and/or GHG emissions in agroforestry systems to traditional agriculture across Canada, with the aims of assessing the benefit of adopting agroforestry for GHG reduction. We then identified data gaps and obstacles that could direct future research. We found that most studies reported increases in vegetation and soil organic C storage in areas with woody species compared to herbaceous crops. Agroforestry systems also reduced the emission of CH 4 and N 2 O, and increased CO 2 respiration from soil, but few studies have examined these gases. The small set of studies we reviewed demonstrated the potential of agroforestry to store terrestrial C and mitigate GHG emissions. However, additional research is required to verify this pattern across geographic regions, determine the regional potential for development of agroforestry systems, and assess the potential atmospheric GHG reduction at regional and national scales.Keywords: carbon flux, methane, mitigation, nitrous oxide, soil carbon RÉSUMÉ L'agriculture canadienne est une source de gaz à effet de serre (GES) et l'agroforesterie pourrait bien contribuer à piéger le carbone (C) et ainsi atténuer les émissions de GES d' origine agricole. L'agroforesterie fait partie intégrante du paysage agricole canadien; on trouve cependant peu de données empiriques permettant d'appuyer l'utilisation de pratiques agroforestières comme moyen d'atténuer les GES. Ce manque de données pourrait expliquer la rareté des politiques encourageant la pratique de l'agroforesterie comme moyen pour atténuer les GES sur la scène agricole canadienne. Nous avons analysé la documentation existante qui compare les stocks de carbone dans la végétation et les sols ou les émissions de GES dans les systèmes agroforestiers à ceux de l'agriculture traditionnelle au Canada en vue d' évaluer les avantages de l'agroforesterie comme moyen de réduire les GES. Nous avons ensuite déterminé les données qui manquent ainsi les autres obstacles qui pourraient faire l' objet de recherches dans l'avenir. Nous avons constaté que la plupart des études consultées rapportent un niveau plus élevé de carbone organique stocké dans la végétation et le sol sur les étendues boisées que sur celles couvertes d'herbacé. L'agroforesterie réduit aussi les émissions de CH 4 et de N 2 O et augmente le CO 2 venant de la respiration du sol même si peu d' études se sont penchées sur ces gaz. Le corpus limité d' études que nous avons consultées ...

Agroforestry systems: Meta‐analysis of soil carbon stocks, sequestration processes, and future potentials

“…AF is an integrated approach to sustainable land use because of its socioeconomic advantages and environmental benefits, including prevention of soil erosion and microclimate improvement, as well as higher crop productivity (Nair et al, , Nair, ; Torralba, ). AF has also been adopted as a greenhouse gas mitigation strategy under the Kyoto Protocol since 2007 (Baah‐Acheamfour et al, ; Stavi & Lal, ). The current review has summarized and documented the lower C loss through greenhouse gas emissions in AF systems compared with croplands (Kim, Kirschbaum, & Beedy, ).…”

Energy Analysis, and Carbon and Water Footprint for Environmentally Friendly Farming Practices in Agroecosystems and Agroforestry

“…According to Baah-Acheamfour et al [44], agroforestry systems could minimize GGE in agricultural production. Agroforestry could increase vegetative carbon, soil organic carbon stocks, and reduce CH 4 and N 2 O emissions compared to cropland.…”

Enrichment Planting and Soil Amendments Enhance Carbon Sequestration and Reduce Greenhouse Gas Emissions in Agroforestry Systems: A Review

“…Trees are also known to help reduce CH 4 and N 2 O emissions, particularly in relation to neighboring cropland [5]. In the sub-tropics, agroforestry systems combining trees and inter-cropped shrubs store more C in vegetation and soils compared to systems with only trees or trees grown with legume or cereals as inter-cropped systems [38,39].…”

“…Agriculture is the second largest emitter of greenhouse gases (GHG) after the energy sector, and is responsible for about 30% of global GHG emissions [1]. Agroforestry, the intentional integration of trees and/or shrubs with herbaceous crops and/or livestock in a production system, is a popular beneficial management practice (BMP) that can mitigate climate change by sequestering carbon (C) and reducing greenhouse gas (GHG) emissions [2][3][4][5][6][7][8]. The Intergovernmental Panel on Climate Change (IPCC) has recognized both afforestation and reforestation as important activities supporting C sequestration [9].…”