Silicon-Coated Phosphate Fertilizer Affects Soil Phosphorus Availability, Photosynthetic Performance, and Radish Tuber Biomass (Raphanus sativus L.)
Willian Gonçalves Souza, Aline de Almeida Vasconcelos, Michel Antoni da Silva, Marcelo Augusto Gutierres Carnelossi, Lia-Tânia Dinis, Wedisson Oliveira Santos, Glauciana da Mata Ataide, Welton Pereira da Rocha Junior, Luiz de OliveiraPhosphorus (P) availability in highly weathered tropical soils is limited by strong adsorption onto iron and aluminum oxides, reducing fertilizer efficiency. Silicon (Si) may modulate P dynamics by competing for adsorption sites. This study evaluated whether silicon-coated triple superphosphate (TSP) improves phosphorus use efficiency, physiological performance, and radish (Raphanus sativus L.) biomass in a greenhouse pot experiment. Six fertilizer treatments (0:0, 1:0, 1:1.5, 1:3, 1:4.5, and 1:6) were assessed using Mehlich-1 P, remaining P, apparent P recovery (PRR) based on whole-plant P uptake, chlorophyll a fluorescence (OJIP), gas exchange, and morpho-agronomic traits. Intermediate P:Si ratios improved extractable P, PRR, photosynthetic responses, and biomass accumulation. The 1:3 treatment gave the highest observed tuber fresh mass (29.38 g plant⁻¹), 66.7% above uncoated TSP (1:0). These associations support further investigation of calcium-silicate-coated TSP; the relative contributions of Si, Ca and possible soil-pH changes could not be separated in this experiment.