Effect of Blended Fertilizers on Yield Performance of Potato (Solanum tuberosum L.) Varieties and Soil Physicochemical Properties in Angacha District, Southern Ethiopia

Abstract

Soil fertility depletion constrains potato productivity in Southern Ethiopia, where smallholder farmers rarely apply optimal nutrient management or improved varieties. This study evaluated the effects of blended fertilizers on the yield performance of potato (Solanum tuberosum L.) varieties and associated changes in soil physicochemical properties in the Angacha District. A field experiment was conducted at a Farmers Training Center using a factorial randomized complete block design with three replications. Treatments comprised five fertilizer levels (control, 100 kg DAP ha⁻¹, 100 kg NPS ha⁻¹, 100 kg NPKSB ha⁻¹, and 150 kg NPKSBZn ha⁻¹), each combined with a uniform application of 200 kg urea ha⁻¹, and three potato varieties (Gudenie, Digemagn, and Beletach). Results revealed that blended fertilizers significantly improved soil available K, B, and CEC, while slight reductions were observed in soil organic carbon, pH, total N, and available P and S. Significant fertilizer-by-variety interactions influenced yield and yield-related traits. The highest total (48.85 t ha⁻¹) and marketable (46.63 t ha⁻¹) tuber yields, along with the maximum harvest index, were recorded for the Gudenie variety treated with 150 kg NPKSBZn ha⁻¹ + 200 kg urea ha⁻¹. These findings underscore the importance of balanced, multi-nutrient fertilization for enhancing potato productivity and sustaining soil fertility. The application of 150 kg NPKSBZn ha⁻¹ + 200 kg urea ha⁻¹, particularly for the Gudenie variety, is recommended as an optimal nutrient management strategy for the study area and similar agro-ecologies.