Evaluation of the effect of a whey-basedbiofertilizer on agronomic and biochemicalparameters in sweet potato [Ipomoea batatas (L.)Lam.]

Objective: To compare the effects of applying an organic biofertilizer (APIS®), formulated from whey, on agronomic and biochemical variables in sweet potato (Ipomoea batatas).Design/Methodology/Approach: A randomized block design was implemented over a 1.5 ha open-field plot. Treatments included foliar applications of APIS®, Bayfolan Forte® (a commercial fertilizer), and water (as a control) at 35- and 65-days post-transplanting (dpt). Sampling was conducted at 35, 60, and 85 dpt to evaluate morphological parameters; quantification of total bacteria and filamentous fungi; elemental analysis; chlorophyll content; total protein; total polyphenols; soluble sugars; and hydrogen peroxide (H2O2) levels.Results: The organic biofertilizer APIS® led to a higher number of tubers and, consequently, greater yield per hectare 22% and 32% higher compared to Bayfolan Forte® and the control, respectively. APIS® also enhanced microbial load during the second sampling, followed by a reduction in the third. No statistically significant differences were observed between the APIS® and control treatments regarding morphological parameters, chlorophyll content, total protein, polyphenols, soluble sugars, and H2O2. However, H2O2 concentrations increased in the Bayfolan Forte® treatment compared to the control.Limitations/Implications: The study was conducted during a single agricultural cycle, which may limit broader generalizations.Findings/Conclusions: APIS® demonstrates potential as a viable biofertilizer for sweet potato cultivation,showing comparable or superior performance to the commercial fertilizer.