Vermicompost and NP Fertilizers Jointly Enhance Growth and Biomass and Improve Quality of Potato Tubers

Abstract

Multi-nutrient-deficiency gives rise to low soil fertility which is one of the major constraints for potato (Solanum tuberosum L.) production in southwestern Ethiopia. That is why, a field experiment was con- ducted in Masha district, southwestern Ethiopia in Belg (February to May) and Meher (June to October) sea- sons during 2020 to evaluate the response of potato to the combined application of vermicompost and mineral nitrogen, and phosphorus and their effect on growth, biomass and physical quality of tubers under rainfed conditions. The treatments included combinations of three rates of vermicompost (2.5, 5, 7.5 t ha–1 ) and three rates of inorganic NP (25, 50, 75%) of recommended dose (165 kg N ha –1 and 60 kg P ha –1 = 100% of recommended dose) with no-fertilizer application treatment (control) and another treatment of 100% inor- ganic NP, making a total of 11 treatments. The experiment was laid out in a randomized complete block design with three replications. The results revealed that the combined application of 7.5 t ha–1 vermicompost and 75% of recommended dose of inorganic NP increased dry biomass, proportion of medium-sized tubers, specific gravity and dry matter content of tubers on the one hand, and delayed the flowering and maturity, on the other. It was concluded that the combined application of 7.5 t ha–1 vermicompost with 75% of recom- mended NP dose in Belg or 7.5 t ha–1 vermicompost with 25% of recommended NP dose in Meher would be the best nutrient management option for the enhancement of biomass and improvement of physical quality of potato tubers in Masha area of southwestern Ethiopia.