Current fertilization guidelines for peach production, established decades ago, are gradually being revisited due to emerging challenges – such as rerising fertilizer costs, nitrate leaching, excessive vegetative growth, and declining fruit quality. These guidelines recommend nitrogen applications of 67.25–78.5 kg/ha, may not fully reflect the variability across individual orchards, production goals, or environmental variability. In 2023, 216 peach trees were established in Clanton, Alabama, to evaluate the effects of three nitrogen fertilization levels (0%, 50%, and 100% of guideline rates) and irrigation on early tree development and nutritional status. The experimental design follows a split-split plot structure, with irrigation as the main plot factor (2 levels: irrigated vs. non-irrigated), fertilization levels as the subplot factor (3 levels: 0%, 50%, 100%), and cultivars (3 cultivars: 'AugustPrince', 'FirePrince', and 'RubyPrince') as the sub-subplot factor. Results from 2023 and 2024 indicate that irrigation significantly enhanced tree height and trunk diameter. Trees receiving 50% and 100% nitrogen performed similarly in growth and CO₂ assimilation, both outperforming unfertilized controls. However, nitrogen deficiency was observed in all 0% treatments and some 50% fertilized, irrigated trees, particularly ‘AugustPrince’ and ‘FirePrince’. ‘RubyPrince’ exhibited the longest terminal shoot length and bud density, followed by ‘FirePrince’ and ‘AugustPrince’, a pattern that aligned with cultivar ripening times. While irrigation improved assimilation and growth, its effect on terminal shoot length was not significant. These findings suggest that moderate fertilization, when paired with appropriate irrigation may help support early vegetative growth. Nonetheless regular nutrient monitoring remains critical. Future work will focus on evaluating yield and fruit quality on these treatments.
