Atmospheric nitrogen deposition budget in the wet savanna of LAMTO in Côte d’Ivoire

In the framework of the International Network to study Deposition and Atmospheric chemistry in Africa (INDAAF), a nitrogen (N) atmospheric deposition budget including wet and dry processes was calculated in Lamto, a wet savana ecosystem in Côte d’Ivoire. For the first time, we performed for a rural tropical African site, a trends study of the N deposition fluxes over a period of 16 years (2000-2015). Annual N deposition budget for this ecosystem is estimated to be 8.21±1.92 kgN.ha-1 .yr-1 that should be considered as an important natural input, close to the critical load of 10 kgN.ha-1 .yr-1. 

In the humid tropical african region, very low nitrogen (N) contents are observed in the soils, making the ecosystems vulnerable to increases of nitrogen deposition due to anthropogenic pressure over the african continent. Biomass burning and agricultural activities are the main sources of nitrogen (N) coumponds in rural areas of tropical Africa. In the framework of the INDAAF (International Network to study Deposition and Atmospheric chemistry in Africa) programme, we performed the analysis of a unique long term database including N gaseous, precipitation and aerosols chemical composition.