Title : Alternative P fertilizer for sustainable phosphorus management in tropical soil: A microscale investigation
Abstract:
Purpose: Phosphorus (P) fixation in highly weathered tropical soils can reduce fertilizer P efficiency and contribute to repeated P applications and the accumulation of legacy P, increasing the potential for P losses and associated environmental problems. This study investigated an alternative P fertilizer combining a silicon (Si) source with triple superphosphate (TSP) to modify P–soil interactions and reduce P fixation at the fertilizer–soil interface.
Methods: Conventional TSP and Si-enriched P fertilizer formulations were evaluated in a tropical soil using a rhizobox system. Microscale P redistribution and P association patterns around fertilizer granules were investigated using advanced elemental mapping and spectroscopic techniques.
Results: Conventional TSP showed strong P retention close to the fertilizer source, consistent with interactions with soil components responsible for P fixation. Incorporation of the Si source altered P redistribution around the fertilizer granules, resulting in different P association patterns and a more dispersed distribution of P in the surrounding soil. The magnitude of these effects varied according to the fertilizer formulation.
Conclusions: The results indicate that incorporating a Si source into P fertilizer can modify microscale P–soil interactions and reduce the concentration of P strongly associated with soil components involved in P fixation. Such alternative fertilizer strategies may contribute to more efficient P use, reducing the need for repeated P inputs and the buildup of legacy P, with potential benefits for sustainable nutrient management and the mitigation of P-related environmental impacts in tropical agroecosystems.
Keywords: Alternative P fertilizer; phosphorus fixation; legacy phosphorus; silicon; phosphorus management; tropical soils; environmental sustainability.
