Akademik Veri Yönetim Sistemi
ZEMDIRBYSTE-AGRICULTURE, cilt.100, sa.2, ss.151-158, 2013 (SCI-Expanded)
This study was conducted to determine the effects of different nitrogen rates (0, 40, 80, 120, 160, 200 and 240 kg ha(-1) N) on the yield, its components and the quality characters of sunflower (Helianthus annuus L.) and to identify the economic optimum N rate for maximum profit under both irrigated and non-irrigated conditions during a 2-year period (2007-2008). As the N rates increased, all of the traits measured significantly increased, except the crude oil content, under both irrigation treatments. Based on the 2-year average, the highest seed yield (2713.6 to 2751.2 kg ha(-1)) and crude oil yield (1012.7 to 1042.5 kg ha(-1)) were obtained using 160 kg ha(-1) N and the higher N rates, with increases of 47.8% and 39.4%, respectively, compared to the control (0 kg ha(-1) N). Similar trends were also obtained for the other traits, except the crude oil content, which was the highest (39-41%) at 0 kg ha(-1) N but the lowest (36-38%) under the higher N rates. The highest mean values for the crude protein content and 1000-seed weight were obtained under the highest N rates (200 and 240 kg ha(-1) N). In 2007, the economic optimum nitrogen rate (EONR) for sunflower was 148.5 kg ha(-1) N under non-irrigated conditions, as compared with 190.0 kg ha(-1) N with irrigation. In 2008, the EONRs for sunflower under non-irrigated and irrigated conditions were 145.1 and 176.7 kg ha(-1) N, respectively. Although the EONR for irrigated conditions was approximately 30-40 kg ha(-1) N more than that for non-irrigated conditions, the seed yield under the irrigation conditions was approximately 65-79% higher compared with the non-irrigated conditions. As a result, it was determined that the economic optimum N rate for sunflower was 145-150 kg ha(-1) N under non-irrigated conditions and 177-190 kg ha(-1) N under irrigated conditions.