Tropical forests play an important role in the global carbon balance, assimilating over a third of the global terrestrial gross primary production [1]. They represent a significant CO2 sink [2] and maintaining this function requires a large and sustained supply of nitrogen (N) [3]. This implies that an understanding of how N losses from tropical soils constrain plant growth and carbon (C) sequestration is critical to assess current and future productivity of tropical forest ecosystems. [4-5]. Despite its importance, a quantified understanding of the different N loss pathways is lacking (ref) [3,6-7]. In contrast to particulate organic C (POC) export, an important pathway of C loss from terrestrial ecosystems, little is know about the magnitude and mechanisms of particulate organic N (PON) export in tropical landscapes, particularly when compared to our understanding of dissolved or gaseous N losses [8]. This is a major knowledge gap because preliminary results have highlighted that lateral particulate export contribute significantly to N balance (N input / N output) in tropical forests that are geomorphologically active [8-10]. PON erosion is therefore an important, yet underappreciated, N loss term that is required to close the N budget of tropical forests [10].