Root growth and dry mass production in orange sweet potato under phosphorus doses

Sweet potato is a root of great global importance in nutrition. Therefore, it is crucial to evaluate its aerial part production and root growth, especially with the application of phosphorus (P). This nutrient is essential for many plants, promoting root growth and energy production (ATP). Thus, this study aims to evaluate root growth and dry matter production in sweet potato under phosphorus fertilization and at two planting times (S1 and S2). The study was conducted in an experimental area of the Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, RN, Brazil. The experimental design was randomized blocks with four replicates. The treatments consisted of P doses (0, 60, 120, 180, and 240 kg ha-1 of P2O5). At 153 days after planting, the dry mass of the aerial part (APDM) and commercial roots (DMCR), aerial part dry mass production (APDMP), the harvest index (HI), classification, and length (LCR), diameter (DCR), and shape (SCR) of the commercial roots were evaluated. The 60 kg ha-1 dose of P2O5 promoted the highest number of commercial roots, mainly for S2, and the predominance of roots with the same shape in both growing seasons for the same dose. The DMCR and HI were higher in S2, essentially for the 120 kg ha-1 dose of P2O5. Dry mass production was higher for S1, showing a strong correlation, with the 60 kg ha-1 dose of P2O5 standing out.