Reuse of dairy waste in sweet potato fertilization: impacts on productivity

There are few studies evaluating the effects of dairy waste application on sweet potato productivity, especially when combined with organic compost fertilization. In this context, the objective was to evaluate the effects of dairy waste fertilization, with or without organic compost, on the yield components and quality of sweet potato. The experiment was conducted under field conditions from April to August 2019 at the UFRPE experimental farm in Garanhuns, Pernambuco, using a randomized block design with different doses of dairy waste (0, 5, 10, and 15 m3 ha-1) in the presence and absence of organic compost, in addition to a control with mineral fertilization. The analyzed variables included ash and starch contents, total and marketable yield, as well as tuber quality parameters. For ash content in the absence of organic compost, the dose of maximum efficiency was 10.21 m3 ha-1, resulting in 0.55% ash, while the number of marketable tubers reached maximum efficiency at 8.05 m3 ha-1, providing 25.09 tubers per plot. The application of dairy waste, either alone or combined with organic compost, promoted increases in sweet potato yield (t ha-1) and quality, showing performance comparable to mineral fertilizer. The highest ash and starch contents were obtained with the exclusive use of dairy waste, highlighting its potential as a sustainable fertilization alternative.