EFFECT OF NITROGEN FERTILIZER RATES AND FOLIAR FERTILIZATION ON GROWTH, YIELD AND YIELD COMPONENTS OF SUNFLOWER

Abstract

Two field experiments were carried out in 2006 and 2007 summer seasons at Sakha Agric. Res. Station (ARC) to study the effect of soil and foliar fertilization on growth, yield and its components of sunflower c.v. Sakha 53. Nitrogen fertilizer rates at 15, 30 and 45 kg N/fed were applied alone or along with foliar spray of urea (2%), single superphosphate (4%) and a mixture of micronutrients (100 ppm Fe + 140 ppm Zn + 120 ppm Mn). Results indicated that vegetative growth traits at 65 days after planting were significantly affected by nitrogen fertilizer rates and foliar spray nutrient application. Plant height, leaf area and dry matter/plant, as well as chlorophyll a and total photosynthetic pigments in leaves were significantly increased with increasing nitrogen level. Foliar nutrient application of urea remarkably improved growth traits. Flowering date was delayed with increasing nitrogen rates and foliar spraying of micronutrient. Increasing nitrogen fertilizer up to 45 kg N/fed led to significant increases in plant height, stem diameter, head diameter, 100-seed weight, seed yield/plant and seed yield/fed However, seed oil% was decreased with increasing nitrogen fertilizer rates. Oil yield/fed was significantly increased with increasing fertilizer nitrogen rate. It could be concluded that nitrogen applied at of 45 or 30 kg/fed with spraying with urea (2%) gave the highest oil yield/fed.