Integrated use of nps blended fertilizer and cattle manure on growth, yield and quality of potato (Solanum tuberosum L.) under Dabo Ghibe Kebele, Seka Werada of Jimma Zone, Southwest Ethiopia

Abstract

Irish potato (Solonaum tuberosum L.) is An important leading tuber crop in Ethiopia. It is an important food security and cash crop for smallholder farmers in Ethiopia. However, the yield of the crop is low at national as well as regional levels which, constrained mainly by low soil fertility. A new blended fertilizer (NPS) containing nitrogen (19% N), phosphorous (38% P2O5) and sulfur (7% S) is recently introduced aiming at substituting DAP in Ethiopian agriculture. There is a need to optimize the fertilizer under farmers’ conditions particularly its use along with organic resources. Therefore, a field experiment was conducted to investigate the effect of combined application of NPS blended fertilizer and cattle manure (CM) on growth, tuber yield and quality of potato on a Nitisol at Dabo-Gibe Kebele, Seka werada in 2016/2017 under irrigation. The objective of this study was to determine the optimum rate of mineral NPS blended fertilizer and CM rate on growth, yield and quality of potato. The treatments consisted of four NPS blended fertilizer levels (0, 50,100 and 150kg ha-1) and four Cattle Manure levels (0, 10, 20 and 30t ha-1).The experiment was laid out as a Randomized Complete Block Design (RCBD) in a factorial arrangement and replicated three times. Data on days to 50% flowering, days to 75% physiological maturity, plant height, main stem number, total tuber yield (t ha-1), marketable tuber yield (t ha-1), unmarketable tuber yield (t ha-1), total tuber number per hill, marketable tuber number per hill per plant, unmarketable tuber number per hill per plant, dry matter content and specific gravity were collected and statistically analyzed using SAS version 9.3 software. Results revealed that combined application of NPS blended fertilizer and CM significantly (P<0.05) influenced days to 50% flowering, days to 75% physiological maturity, plant height, total tuber yield (t ha-1), marketable tuber yield (t ha-1), total tuber number per hill, marketable tuber number per hill and specific gravity. However, main stem number and dry matter content were not affected by the combined application of NPS blended fertilizer and cattle manure. Unmarketable tuber number and yield was also not affected by the main effects of NPS blended fertilizer and CM and as well as their interaction. The highest total tuber yield (40.23 t ha-1) was obtained by applying 150 kg ha-1 NPS bended fertilizers+30 t ha-1CM. Based on the partial budget analysis, combined application of 100 kg ha-1NPS bended fertilizers+30tha-1CM gave the maximum net return of Birr 138,513 ha-1 with an acceptable marginal rate of return (51.1%). The total nitrogen, available phosphorus and organic carbon content of the experimental soil were also increased due to the interaction of mineral NPS blended fertilizers and cattle manure at their highest rates. In conclusion, the results revealed that combined application of 150 kg ha-1NPS fertilizers and cattle manure at 30 t ha-1 significantly increased total tuber yield (40.23tha-1) of potato and restore of N, P and organic carbon of soil. In economic point of view, combined application of 100 kg ha-1NPS blended fertilizers and 30 t ha-1CM is found economically feasible and can be recommended for potato growers around Seka Wereda.