Effect of crop geometry and split application of N on nutrient uptake and yield of rainfed sunflower

Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore, during the Northeast monsoon (October-December) seasons of 1997 and 1998 in a split plot design to study the effect of crop geometry and split application of N on nutrient uptake and yield of rainfed sunflower. The main plot treatments consisted of three levels of crop geometry viz. 80, 100 and 120% of recommended population with a spacing 30 * 37.5cm 30 * 30 cm and 30 * 5 cm respectively and the sub-plot treatments formed six N split-levels and treatments were replicated thrice. The results revealed that the nutrient uptake of sunflower was higher with closer spacing of 30 * 25 cm than wider spacing of 30 * 37.5 cm. The plants under closer spacing (30 * 25cm) extract more moisture than wider spacing of 30 * 37.5 cm. The seed yield was higher at closer spacing (30 * 25cm) in 1997 (810 kg ha') and at wider spacing (30 * 37.5cm) in 1998 (1022 kg ha). In both the years the split application of nitrogen resulted in higher nutrient uptake and seed yield as compared to entire dose as basal dressing.