The environmental impacts of agroforestry in agri-food systems: a life cycle assessment approach

Summary in the original language of the document

Agricultural activities contribute to several environmental problems that lead to environmental degradation (FAO, 2013). These problems include biodiversity loss and climate change (Knudsen et al., 2019). In order to address some of these issues, a variety of alternative farming systems have been proposed (Garibaldi et al., 2017). Agroforestry Systems (AFS) are one such alternative where trees, crops
or livestock can be combined (FAO, 2013; Garibaldi et al., 2017). The question of whether AFS are favorable for the environment can be investigated through a Life Cycle Assessment (LCA) (Baumann & Tillman, 2004). Unlike monocultures or specialized livestock systems, the assessment of the effects and interactions of AFS on the environment are far more complex. It is therefore important to explore how the existing methodological choices in current LCA studies of AFS capture fundamental elements grounded in the general literature of agroforestry. Thus, the objective of this abstract is twofold. First, to identify, select and review a collection of LCA studies of AFS that focus on the provision of food. Second, to critically analyze gaps in knowledge in narrative and descriptive forms. To achieve this abstracts objective, a preliminary systematic review was conducted. The review was based on pre-defined inclusion criteria following established guidelines and protocols (Bilotta et al., 2014; Zumsteg et al., 2012).
Preliminary results suggest that in the past decade, the most prevalent studied AFS were agrosilvicultural.
This was followed by silvopastoral and agrosilvopastoral to a lesser extent. Shade trees, cattle and cereals were the main agroforestry components addressed by the literature. Geographically, studies were concentrated in tropical zones, mainly in South America. Only a handful of studies were in temperate regions, such as Southern Europe. Most functional units were based on mass or area, followed by monetary, energy or composite units. Systems boundaries were primarily defined from cradle to gate.
The reviewed studies focused on three major impact categories: climate change, eutrophication potential and acidification potential. Environmental hotspots were mainly linked to upstream emissions (e.g. fertilizers, animal feed and agrochemicals) followed by downstream emissions (e.g. diesel, soil management and enteric fermentation).
The preliminary results suggest a great deal of variation among the reviewed studies and their methodological choices across the four phases of an LCA. In addition to challenging the interpretation, this variation may hinder the understanding of the possible impacts of AFS on gri-food systems. Thus, the development of AFS indicators may require further exploration and incorporation into LCA since they have not been specifically outlined in the existing LCA literature.