Response of Potato (Solanum tuberosum L.) to the Application of Mineral Nitrogen and Phosphorus Fertilizers under Irrigation in Dire Dawa, Eastern Ethiopia

Abstract

Potato is an important cash and food security crop in eastern Ethiopia. However, nutrient requirement of the crop under warmer dry conditions has not been studied in the region. Therefore, an experiment was conducted at Dire Dawa, eastern Ethiopia to investigate the response of potato to the application of mineral nitrogen and phosphorus fertilizers under irrigated condition. Four rates of nitrogen (0, 56, 112 and 168 Kg N ha^-1) and four rates of phosphorus (0, 46, 92 and 138 Kg P₂O₅ ha^-1) were combined in 4 x 4 factorial arrangement and laid out in randomized complete block design with three replications. Improved potato variety “Bubu” was used as a test crop. Growth, yield and yield components data were collected and analyzed. Results of the study revealed that both the main and interaction effects of nitrogen and phosphorus affected most of the studied growth and yield parameters of the crop. Growth, yield, and yield components of the crop were obtained in response to the application of 56 kg N ha^-1 and 138 kg P₂O₅ ha^-1, with reductions in most of parameters studied as the rate of nitrogen was increased beyond this level.  However, the cost-benefit analysis indicated that application of nil kg N ha^-1and 138 kg P₂O₅ ha^-1 would lead to significant economic benefits for farmers.

Keywords: Nitrogen, Phosphorus, Interaction, Potato.