The impacts of agroforestry interventions on agricultural productivity, ecosystem services, and human well‐being in low‐ and middle‐income countries: A systematic review

Abstract

Background: Agroforestry, the intentional integration of trees or other woody perennials with crops or livestock in production systems, is being widely promoted as a conservation and development tool to help meet the 2030 UN Sustainable Development Goals. Donors, governments, and nongovernmental organizations have invested significant time and resources into developing and promoting agroforestry policies and programs in low-and middle-income countries (LMICs) worldwide. While a large body of literature on the impacts of agroforestry practices in LMICs is available, the social-ecological impacts of agroforestry interventions is less well-studied. This knowledge gap on the effectiveness of agroforestry interventions constrains possibilities for evidence-based policy and investment decisions to advance sustainable development objectives.Objectives: The primary objective of this Campbell systematic review was to synthesize the available evidence on the impacts of agroforestry interventions in LMICs on agricultural productivity, ecosystem services, and human well-being. The secondary objectives were to identify key pathways through which agroforestry interventions lead to various outcomes and how the interventions affect different sub-groups of the population.Search Methods: This review is based on a previously created evidence and gap map (EGM) of studies evaluating the impacts of agroforestry practices and interventions on agricultural productivity, ecosystem services, and human well-being. We included published and unpublished literature in the English language covering the period between 2000 and October 20, 2017. We searched six academic databases and 19 organization websites to identify potentially relevant studies. The search was conducted for our EGM in mid-2017, and we did not conduct an additional search for this systematic review.

Agroecological practices increase farmers’ well-being in an agricultural growth corridor in Tanzania

“…There is limited empirical evidence in the literature for the relationship between agroecological intensity and smallholder farmer well-being in rural landscapes in the tropics (Miller et al 2020). Still, our results align with previous studies indicating that, despite high variability, the overall impact of sustainable agricultural practices on livelihoods and well-being in the tropics tends to be positive (Reed et al 2017;Mdee et al 2018;Leakey 2020;Castle et al 2021).…”

“…This association is highly variable in the literature. For example, a recent review failed to find significant effect of agroforestry interventions on yields, although it found a neutral to positive impact on nutrition and food security (Castle et al 2021). Food security for smallholder farmers in the tropics is highly linked to staple crop yield (IFAD and UNEP 2013).…”

“…It is relevant to understand how both approaches affect well-being, inclusively when both are being simultaneously implemented at farm or landscape scale. For now, we have an incomplete picture of the impacts of sustainable agricultural practices on food production and well-being over a wide range of farming systems (Reed et al 2017;Castle et al 2021). Policymakers should not assume that industrial farming intensification will inevitably result in higher human well-being, if that intensification is done at the expense of natural areas (Rasmussen et al 2018) and/or human health (de Bon et al 2014).…”

“…Policymakers should not assume that industrial farming intensification will inevitably result in higher human well-being, if that intensification is done at the expense of natural areas (Rasmussen et al 2018) and/or human health (de Bon et al 2014). Future research should focus on detailing trade-offs and synergies adjusted to local contexts, including on outcomes (e.g., profitability, food security) that are most relevant to smallholder farmers and specifically on how vulnerable groups are affected (Below et al 2012;Kleijn et al 2019;Castle et al 2021). Moving forward from our observational study, we recommend measuring the impact on well-being of specific interventions linked to sustainable agricultural practices using quasi-experimental approaches (Miller et al 2020).…”

A quantitative appraisal of selected agroforestry studies in the Sub-Saharan Africa

“…(2014) , Tanveer et al. (2017) , Castle et al. (2021) Scattered agroforestry trees A technology where agroforestry trees are dispersed in crop and grazing lands Can adapt to different agroecological niches depending on the tree species and crop combination Food, feeds and fodder provision, biomass source Soil properties and fertility improvement, shade provision, microclimate control, biodiversity habitat and conservation, nutrients cycling Low costs of tree management, income generation from different tree products Competition between crops and trees for water and nutrients Kelso and Jacobson, (2011) , Tengnas (1994) , Castle et al.…”