Potential Greenhouse Gas Mitigation through Temperate Tree-Based Intercropping Systems

Abstract

Increasing awareness of global climate change has pressured agricultural producers to reduce greenhouse gas (GHG) emissions while at the same time encouraging them to maintain food production needed for an increasing population. Tree-based intercropping (TBI) systems are believed to be useful in climate change mitigation, especially in temperate regions, due to their potential to reduce GHG emissions from agricultural practices. The purpose of this paper is therefore to review some of the research conducted on GHG mitigation in TBI in southern Ontario and Quebec, Canada. Research conducted at the University of Guelph Agroforestry Research Station (GARS) indicated that TBI systems had the potential to lower N2O emissions by 1.2 kg ha-1 y-1 compared to a conventional agricultural field cropping system. Trees can assimilate residual nitrate (NO3-) left from nitrogen (N) fertilizer applications, thereby leaving less NO3- available for denitrification and subsequently reducing N2O losses. Carbon sequestration is also enhanced in TBI systems as carbon (C) is stored in both above and below ground tree components. Soil Organic Carbon (SOC) is higher in systems incorporating trees because tree litter decomposes slowly, therefore reducing CO2 loss to the atmosphere. The C sequestration potential of TBI systems and the possibility to include fast-growing tree species for bioenergy production in TBI systems make it a valid solution to mitigate climate change in temperate regions. The opportunity of C trading credits to offset the costs of implementing a TBI system and provide additional income to farmers could facilitate the adoption of TBI amidst agricultural producers in temperate regions.

Impact of earthworm <i>Lumbricus terrestris</i> living sites on the greenhouse gas balance of no-till arable soil

“…For instance, the higher content of mineral nitrogen and soil moisture favour denitrification, which was manifested as elevated values of potential denitrification in our measurements. In our field site, soil moisture was nearly 40 %, corresponding to 80 % WFPS, which is suitable for earthworm N 2 O contribution (Evers et al, 2010). Another potential mechanism for increased N 2 O emissions in the field are the burrows that may act as large pores that ease the diffusion of N 2 O from the bottom soil and allow more of the N 2 O ending up in the atmosphere without being reduced to N 2 .…”

Intercropping with Switchgrass Improves Net Greenhouse Gas Balance in Hybrid Poplar Plantations on a Sand Soil

“…Few studies have evaluated greenhouse gas emissions from the intercropping of woody and perennial grasses such as switchgrass. Evers et al (2010) reported mean N 2 O emission from monoculture and tree-based intercropping were 10.7 and 7.5 g ha -1 d -1 , respectively.…”

“…These systems commonly include tree or other woody species often from tropical or semi-tropical environments within agroforestry production systems (Suresh and Rao, 1999;Nissen et al, 2001;Prasad et al, 2010), combined with annual food crops grown using low inputs (Gliessman, 2007;Lithourgidis et al, 2011;Gebru, 2015). Few studies of intercropping woody species with annual food crops in North America have been conducted (Thevathasan and Gordon, 2004;Rivest et al, 2009;Evers et al, 2010). Thevathasan and Gordon (2004) summarized 15 yr of intercropping research with ten tree species and four annual grain crops.…”

“…They found younger tree stands did not reduce grain yields when intercropped. However, competition increased with older stands of hybrid poplars with all annual grain crops (Evers et al, 2010). Intercropping of trees with annuals was shown to improve N and C cycling (Allen et al, 2004;Fang et al, 2010), enhance wildlife habitat (Stainback and Alavalapati, 2004), and reduce erosion and ground and surface water contamination (Zamora et al, 2009;Bergeron et al, 2011).…”

“…These benefits result from a diversification of outputs and a shortened time to reach economic production (Holzmueller and Jose, 2012;Susaeta et al, 2012). Evers et al (2010) reported that tree-based intercropping systems stored more C than conventional cropping systems by increasing C storage in the biomass of planted trees and increased soil organic matter storage through C inputs to the soil. Further, they suggested that tree based intercropping in temperate regions not only sequestered atmospheric CO 2 , but also reduced N 2 O emissions compared with conventional monocultures.…”