INFLUENCE OF SEASONAL DISPARITY ON NPK UPTAKE IN SUNFLOWER
F. U. Hassan and S. Kaleem*
Pir Mehr Ali Shah, Arid Agriculture University Rawalpindi, Pakistan
*Adaptive Research Complex, Dera Ghazi Khan, Pakistan
Corresponding Author E-mail: firstname.lastname@example.org
Crop-environment interaction is a key factor in the assessment of crop performance, thus nutrients uptake by crop plants require coincidence of vegetative and reproductive stages with suitable environmental conditions. The influence of seasonal variation on NPK uptake in sunflower was studied through field experiments executed at Pir Mehr Ali Shah, Arid Agriculture University Rawalpindi, Pakistan for two years (2007 & 08) during spring and autumn. Four Sunflower hybrids, Alisson-RM, Parasio-24, MG-2 and S-278 were planted in Randomized Complete Block Design with four replications using seed rate of 5 kg ha-1. The data on nitrogen, phosphorus and potassium uptake by plants was recorded at physiological maturity. NKP uptake was significantly influenced by prevailing season. Overall, spring planted crop exhibited significantly higher values for NPK uptake at physiological maturity than during autumn which may be attributed to the longer crop life span facilitating nutrient uptake. However, shorter crop life cycle of autumn planted crop limited uptake. Amongst hybrids, MG-2 took up the maximum quantities of NPK during both the seasons (spring & autumn) probably due to higher yield potential. It may be concluded that farmers planting autumn sunflower should reduce NPK inputs as output would be strongly influenced by shorter growing season.
Key words: Seasonal variation; NPK uptake; Sunflower; crop life cycle