Investigating drivers of active nitrification in organic horizons of tropical forest soils

• Some O horizons showed higher nitrification rate than mineral horizons. Both total N and pH were positively correlated with in horizon. Nutrient richness litters supported active Nitrification horizon increased along a threshold of 5.5–6.0. High nitrate leaching has been observed from the some tropical forests; however, drivers high production (active nitrification) these have not yet identified. This study investigated forest soils by focusing on two most widely recognized controlling factors nitrification, N, pH. We collected eight forests Cameroon, Indonesia, Malaysia measured gross rates. significantly rates horizons, indicating that potential for nitrification. Gross both pH, chemical properties (e.g., content P, base cations) intercorrelated. These correlations suggested underlying driver was nutrient litter. Results also indicated around values elucidate subsequent could be driven nutrient-rich litter, possibly derived soil fertility tree species.