Phosphorus influence on seedling growth of Caatinga tree species

This study assessed how phosphorus rates affect the growth and nutritional health of seedlings from three native forest species in the Brazilian semi-arid region: Libidibia ferrea, Erythrina velutina, and Piptadenia stipulacea. The experiment was conducted at the Center for Teaching and Research in Urban Agriculture, employing a randomized block design with a 3 × 5 factorial arrangement, involving three tree species (Piptadenia stipulacea, Erythrina velutina, and Libidibia ferrea) and five phosphorus application rates (100, 150, 200, 250, and 300 mg dm-³). Measurements included height, stem diameter, number of leaves, dry biomass, shoot-to-root ratio (SRR), height-to-diameter ratio (HDR), phosphorus use efficiency (PUE), phosphorus accumulation (PA), and the Dickson quality index (DQI). The results showed species-specific responses. Piptadenia stipulacea responded more strongly to phosphorus, with notable increases in growth and nutrient absorption. In contrast, Erythrina velutina and Libidibia ferrea showed minimal changes across treatments. These findings indicate that phosphorus needs differ among native forest species, suggesting that fertilization should be customized to meet each species' specific requirements for optimal seedling production.