Asian Journal of Plant and Soil Sciences

The experiment was conducted at the Teaching and Research Farm of Akwa Ibom State University, Obio Akpa Campus, Akwa Ibom State, Nigeria, to determine the effects of regenerative and conventional practices on soil health and nutritional quality in sweet potato varieties. The study was arranged in a split-plot experiment fitted into a randomised complete block design (RCBD) with three replications. The main plot consisted of the two OFSP varieties, while the subplot comprised five nutrient management treatments: no amendment (CA), 400 kg ha⁻¹ NPK fertilizer (CB), 5 t ha⁻¹ poultry manure + 200 kg ha⁻¹ organomineral fertilizer (RA), 10 t ha⁻¹ poultry manure (RB), and 5 t ha⁻¹ biochar (RC). Nutrient management practices significantly influenced growth and yield parameters. The regenerative treatments, particularly RA and RB, consistently enhanced leaf production, vine growth, and storage root yield compared with the conventional fertilizer and control treatments. The highest storage root yield was obtained under the RA treatment, while the unamended control (CA) recorded the lowest values across both varieties. Significant interaction effects between variety and fertilizer were observed for leaf number and vine length, whereas most yield parameters showed no significant variety × fertilizer interaction. Nutritional quality was also influenced by nutrient management practices, with poultry manure (RB) generally producing the highest beta-carotene concentration and micronutrient contents; vitamin B6 was not significantly affected by fertilizer, and vitamin C followed a distinct pattern in which sole NPK application gave the lowest value of any treatment. Post-harvest soil analysis indicated improvements in selected soil fertility indices, particularly pH, exchangeable calcium, and exchangeable acidity under regenerative nutrient management treatments relative to the control and sole NPK fertilizer treatment. The study demonstrates that regenerative nutrient management practices, particularly the combined application of poultry manure and organomineral fertilizer, offer a sustainable strategy for improving the growth, yield, nutritional quality, and soil health of orange-fleshed sweet potato in the humid tropical environment of Akwa Ibom State, Nigeria.