IMPACT OF PLANT DENSITIES AND NPK FERTILIZATION ON GROWTH AND OPTIMUM ECONOMIC RETURN OF SUNFLOWER

A field experiment was conducted to study the response of sunflower hybrid (Hysun-33) to different plant densities (11.11, 5.5 and 3.7 plants m^-2) and NPK levels (50:50:0, 100:100:50 and 150:120:100 kg ha-1) at the Faculty of Agriculture, Gomal University, Dera Ismail Khan during spring 2011. Growth and yield traits of sunflower such as days to flowering, plant height, disc diameter, 1000-seed weight, number of seeds disc^-1, seed yield, biomass yield and harvest index were significantly (P≤0.05) affected by planting densities and NPK levels. The highest plant height (162.88 cm), seed yield (4645.8 kg ha^-1) and biomass production (19736 kg ha^-1) was recorded under the highest plant density (11.11 plants m^-2) used in this experiment that received the highest fertilizer dose of 150:120:100 NPK kg ha^-1. On the other hand, the head diameter, 1000 seed weight, and seeds head^-1 were the lowest under lowest planting density (3.7 plants m^-2) that received the highest fertilizer dose. It is important to note that the highest benefit-cost ratio (BCR = 3.9) was obtained with highest planting density (11.11 plants m^-2) and highest fertilizer dose (150:120:100 NPK kg ha^-1). Based on this data 11.11 plants m^- 1plant density and 150:120:100 kg ha^-1 NPK fertilizers are recommended to get the highest yield and net return of sunflower under the agro-climatic conditions of Dera Ismail Khan.