Agroecology in Canada: Towards an Integration of Agroecological Practice, Movement, and Science

Isaac, Marney E.; Isakson, S. Ryan; Dale, Bryan; Levkoe, Charles Z.; Hargreaves, Sarah K.; Méndez, V. Ernesto; Wittman, Hannah; Hammelman, Colleen; Langill, Jennifer C.; Martin, Adam R.; Nelson, Erin; Ekers, Michael; Borden, Kira A.; Gagliardi, Stephanie; Buchanan, Serra W.; Archibald, Sarah; Ciani, Astrid Gálvez

doi:10.3390/su10093299

Cited by 45 publications

(26 citation statements)

References 83 publications

(83 reference statements)

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“…Over the past two decades, there has been a considerable expansion in research on alternative agricultural systems (Altieri 1999;Wezel and Soldat 2009;Tomich et al 2011). Applications of agroecological principles to the design of agroecosystems have gained momentum as a contemporary lens to critique, evaluate, and manage environmental and socio-economic issues surrounding agricultural landscapes (Méndez et al 2013;Isaac et al 2018). Notably, the integration of trees to cropping systems, or agroforestry, addresses many of the most pressing issues of our time, including food security, biodiversity loss, and climate change (Jose 2009;Somarriba et al 2012;Tscharntke et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Nutrient acquisition strategies in agroforestry systems

2019

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Background Disentangling nutrient acquisition strategies between trees and crops is central to understanding positive nutrient interactions in agroforestry systems for improved low-input agriculture. However, as plants are responsive to a complex soil matrix at multiple scales, generalizable diagnostics across diverse agroforests remains challenging. Scope We synthesize research at various scales of the tree-crop interface that are cumulatively hypothesized to underpin nutrient acquisition strategies in agroforestry systems. These scales span the whole root system to fine-scale sites of acquisition actively engaged in biological and chemical interactions with soil. We target vertical and horizontal dimensions of acquisition patterns; localized root-soil dynamics including biological associations; root-scale plasticity for higher acquisition; and nutrient additions via biological nitrogen fixation and deep soil nutrient uplift. We consolidate methodological advances and the effects of environmental change on wellestablished nutrient interactions. Conclusions Root distribution patterns remain one of the most universal indicators of nutrient acquisition strategies in a range of agroforestry systems, while root functional traits are emerging as an effective root-scale indicator of nutrient acquisition strategy. We validate that in agroforestry systems crop root functional traits reveal bivariate trade-offs similar to, but weaker than, crops in monoculture, with mechanistic links to nutrient acquisition strategies. While interspecific root overlap may be associated with nutrient competition, clear cases of enhanced chemically and microbially meditated processes result in species-and management-specific nutrient facilitation. We argue for agroforestry science to use distinct and standardized nutrient acquisition indicators and processes at multiple scales to generate more nuanced, while also generalizable, diagnostics of tree-crop interactions. And extensive research is needed on how agroforestry practices stabilize key nutrient acquisition patterns in the face of environmental change.

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Section: Introductionmentioning

confidence: 99%

Nutrient acquisition strategies in agroforestry systems

2019

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“…Similarly, SDG 2 Target 2.4 calls for “…resilient agricultural practises…” that confer a multitude of ecosystem services beyond yield alone. Diversified agroecosystems that incorporate multiple crop species are key in meeting this target [45], however, political support for such systems remain limited [46, 47]. Our analyses suggests that at regional scales, diversified polyculture assemblages would also be critical in addressing both the trend towards, and consequences of, increasing homogenization in agricultural systems globally.…”

Section: Discussionmentioning

confidence: 99%

Regional and global shifts in crop diversity through the Anthropocene

et al. 2019

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The Anthropocene epoch is partly defined by anthropogenic spread of crops beyond their centres of origin. At global scales, evidence indicates that species-level taxonomic diversity of crops being cultivated on large-scale agricultural lands has increased linearly over the past 50 years. Yet environmental and socio-economic differences support expectations that temporal changes in crop diversity vary across regions. Ecological theory also suggests that changes in crop taxonomic diversity may not necessarily reflect changes in the evolutionary diversity of crops. We used data from the Food and Agricultural Organization (FAO) of the United Nations to assess changes in crop taxonomic- and phylogenetic diversity across 22 subcontinental-scale regions from 1961–2014. We document certain broad consistencies across nearly all regions: i) little change in crop diversity from 1961 through to the late 1970s; followed by ii) a 10-year period of sharp diversification through the early 1980s; followed by iii) a “levelling-off” of crop diversification beginning in the early 1990s. However, the specific onset and duration of these distinct periods differs significantly across regions and are unrelated to agricultural expansion, indicating that unique policy or environmental conditions influence the crops being grown within a given region. Additionally, while the 1970s and 1980s are defined by region-scale increases in crop diversity this period marks the increasing dominance of a small number of crop species and lineages; a trend resulting in detectable increases in the similarity of crops being grown across regions. Broad similarities in the species-level taxonomic and phylogenetic diversity of crops being grown across regions, primarily at large industrial scales captured by FAO data, represent a unique feature of the Anthropocene epoch. Yet nuanced asymmetries in regional-scale trends suggest that environmental and socio-economic factors play a key role in shaping observed macro-ecological changes in the plant diversity on agricultural lands.

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“…While understandings of agroecology are epistemologically plural and thus subject to some debate (Isaac et al, 2018), there is growing consensus that it is best conceptualized as three distinct, though interrelated, elements: a scientific discipline; a set of practices; and a social movement (Méndez et al, 2013;Gliessman, 2014;Levidow et al, 2014). As a discipline, agroecological research seeks to develop and systematize knowledge in an effort to better understand the socio-ecological relationships that characterize agroecological systems.…”

Section: Agroecology Innovation Gender and Developmentmentioning

confidence: 99%