Legume tree-based farming systems sit at a crucial nexus of
agroecological sustainability. Their capacity to support
microbial N2 fixation can increase soil nitrogen (N) availability
and therefore improve soil fertility, crop yields, and support
long-term stewardship of natural resources. However,
increasing N availability oftentimes catalyzes the release of
N into the surrounding environment, in particular nitrous oxide
(N2O) — a potent greenhouse gas. We summarize current
knowledge on the agroecological footprint of legume-based
agroforestry and provide a first appraisal of whether the
technology represents a pathway toward sustainable
development or an environmental hazard