TY - JOUR

T1 - Representing crop rotations in life cycle assessment: a review of legume LCA studies

AU - Porto Costa, Marcela

AU - Chadwick, Dave

AU - Saget, Sophie

AU - Rees, Robert M

AU - Williams, Michael

AU - Styles, David

PY - 2020/8/22

Y1 - 2020/8/22

N2 - Purpose There is an imperative to accurately assess the environmental sustainability of crop system interventions in the contextof food security and climate change. Previous studies have indicated that the incorporation of legumes into cereal rotations couldreduce overall environmental burdens from cropping systems. However, most life cycle assessment (LCA) studies focus onindividual crops and miss environmental consequences of inter-annual crop sequence and nutrient cycling effects. This reviewinvestigates state-of-the-art representation of inter-crop rotation effects within legume LCA studies.Methods A literature review was undertaken, starting with a search for all peer-reviewed articles with combinations of ‘LCA’,‘legumes’ and ‘rotations’ or synonyms thereof. In total, 3180 articles were obtained. Articles were screened for compliance withall of the following requirements: (i) reporting results based on LCA or life cycle inventory methodology; (ii) inclusion of (a)legume(s); (iii) the legume(s) is/are analysed within the context of a wider cropping system (i.e. rotation or intercropping).Seventy articles satisfying these requirements were analysed.Results and discussion We identified three broad approaches to legume LCA. Most studies involved simple attributional LCAdisregarding important interactions across years and crops in rotations. N-fertilizer reduction through legume residue N carryoveris either disregarded or the benefit is attributed to the following crop in such studies, whilst N leaching burdens from residues areusually attributed to the legume crop. Some studies applied robust allocation approaches and/or complex functional units toenable analysis of entire rotation sequences, accounting for nutrient cycling and break crop effects. Finally, a few studies appliedconsequential LCA to identify downstream substitution effects, though these studies did not simultaneously account for agro-nomic effects of rotational sequence changes.Conclusions We recommend that LCA studies for legume cropping systems should (i) evaluate entire rotations; (ii) representnitrogen and ideally carbon cycling; (iii) for attributional studies, define at least two functional units, where one should encom-pass the multifunctional outputs of an entire rotation and the other should enable product footprints to be calculated; (iv) forCLCA studies, account for both agronomic changes in rotations and markets effects; (v) include impact categories that reflecthotspots for agricultural production.

AB - Purpose There is an imperative to accurately assess the environmental sustainability of crop system interventions in the contextof food security and climate change. Previous studies have indicated that the incorporation of legumes into cereal rotations couldreduce overall environmental burdens from cropping systems. However, most life cycle assessment (LCA) studies focus onindividual crops and miss environmental consequences of inter-annual crop sequence and nutrient cycling effects. This reviewinvestigates state-of-the-art representation of inter-crop rotation effects within legume LCA studies.Methods A literature review was undertaken, starting with a search for all peer-reviewed articles with combinations of ‘LCA’,‘legumes’ and ‘rotations’ or synonyms thereof. In total, 3180 articles were obtained. Articles were screened for compliance withall of the following requirements: (i) reporting results based on LCA or life cycle inventory methodology; (ii) inclusion of (a)legume(s); (iii) the legume(s) is/are analysed within the context of a wider cropping system (i.e. rotation or intercropping).Seventy articles satisfying these requirements were analysed.Results and discussion We identified three broad approaches to legume LCA. Most studies involved simple attributional LCAdisregarding important interactions across years and crops in rotations. N-fertilizer reduction through legume residue N carryoveris either disregarded or the benefit is attributed to the following crop in such studies, whilst N leaching burdens from residues areusually attributed to the legume crop. Some studies applied robust allocation approaches and/or complex functional units toenable analysis of entire rotation sequences, accounting for nutrient cycling and break crop effects. Finally, a few studies appliedconsequential LCA to identify downstream substitution effects, though these studies did not simultaneously account for agro-nomic effects of rotational sequence changes.Conclusions We recommend that LCA studies for legume cropping systems should (i) evaluate entire rotations; (ii) representnitrogen and ideally carbon cycling; (iii) for attributional studies, define at least two functional units, where one should encom-pass the multifunctional outputs of an entire rotation and the other should enable product footprints to be calculated; (iv) forCLCA studies, account for both agronomic changes in rotations and markets effects; (v) include impact categories that reflecthotspots for agricultural production.

U2 - https://doi.org/10.1007/s11367-020-01812-x

DO - https://doi.org/10.1007/s11367-020-01812-x

M3 - Article

VL - 25

SP - 1942

EP - 1956

JO - International Journal of Life Cycle Assessment

JF - International Journal of Life Cycle Assessment

SN - 0948-3349

ER -