<p>Emissions from deforestation and savannah fires can travel over long distances and contribute to nutrient deposition in intact tropical forests, where phosphorus limits productivity. The magnitude of this deposition and its influence on the carbon sink, however, remain uncertain. Here we used satellite- and model-based geospatial datasets with feature importance analysis to quantify the influence of fire-derived nutrient inputs on Amazon rainforest productivity. Atmospheric transport modelling indicated that plumes originating in the southern arc of deforestation deliver aerosols into the Amazon basin, creating a south-to-northeast gradient in phosphorus deposition across the Amazon rainforest. This gradient in phosphorus deposition aligned with spatial patterns in sun-induced fluorescence, a proxy for gross primary productivity. We show that long-term phosphorus deposition was the strongest predictor of gross primary productivity, accounting for 22.5% of total spatial variability, and was linked to gains of 7.4 gC m⁻² yr⁻¹ per 1 mg P m⁻² yr⁻¹ deposited. Our results demonstrate that fire-derived deposition can alleviate chronic nutrient limitations in undisturbed tropical forests and influence spatial patterns of productivity. This nutrient fertilization partially offsets carbon losses from deforestation and fires, with important implications for global carbon budgets.</p>