Productivity and quality of potato as affected by phosphorus and foliar application of nitrogenous fertilizer (urea)

Potato (Solanum tuberosum L.) is a main cash and food crop in Pakistan. Growth, yield and quality of potato is greatly affected by its nutritional management. Foliar application of urea reduces nitrogen losses and increases plant nitrogen use efficiency. This study was planned to evaluate the effect of soil applied phosphorus (DAP) and foliar application of nitrogenous fertilizer (urea) on growth, yield and quality of potato. In view of above statement, a field experiment was conducted in Vegetable Experimental Area of the Institute of Horticultural Sciences, University of Agriculture, Faisalabad during 2013-14. Experiment was consisted of four different treatments of nitrogen (urea, 46% N) and phosphorus (DAP, 46% P) including a control treatment. Treatments included T0 farmer application (DAP 160 kg/acre + Urea 300 kg/acre), T1 (DAP 140 kg/acre + Urea 5 kg/acre), T2 (DAP 120 kg/acre + Urea 7 kg/acre) and T3 (DAP 100 kg/acre + Urea 9 kg/acre). DAP fertilizer was applied to soil as basal dressing at the time of sowing. Foliar application of nitrogenous fertilizer (urea) was given at 30, 40, 50, 60 and 70 days after sowing in five split doses. Maximum plant height (49.34cm), maximum no. of tubers per plant (8.53) and maximum total yield (19.37 ton/ha) and marketable yield (15.27 ton/ha) was obtained with T3 (DAP 100 kg/acre + Urea 9 kg/acre). Maximum diameter (53.3 mm) and dry weight (127g) was also produced by T3 (DAP 100 kg/acre + Urea 9 kg/acre). Tuber volume remained non-significant for different treatments. When considering mineral analyses, highest percentage of nitrogen (1.63%) and potassium (1.77%) was produced by T0 (DAP 160 + Urea 300 kg/acre) while phosphorus remained non-significant for all treatments. Maximum protein (2.20 %) was obtained with T3 (DAP 100 kg/acre + Urea 9 kg/acre) while vitamin C (0.18 mg/g) was maximum produced with T1 (DAP 140 kg/acre + Urea 5 kg/acre). Maximum dry ash weight (2.68 mg) was obtained with T0 (DAP 160 kg/acre + Urea 300 kg/acre). TSS (Brix), dry matter, moisture content, reducing, non-reducing and total sugars (%) produced non-significant results for different treatments.