تاثیر مقادیر کود نیتروژن در مراحل مختلف رشدی بر انتقال مجدد ماده خشک و صفات موثر بر انباشت ماده خشک در دانه جو

In order to investigate application of nitrogen rates at different growth stages effects on dry matter remobilization and effective traits at dry matter accumulative of grain in spring barley (Hordeum Vulgare L.), an experiment was conducted as factorial based on randomized complete block design with three replications at the research farm, University of Mohaghegh Ardabili during 2012 cropping. Experimental factors were: nitrogen rates in four levels (0, 60, 120, and 180 Kg N.ha-1) as urea and nitrogen application at different growth stages in four levels (T0 at planting stage + at stem elongation ), (T1: at planting + stem elongation + at ear emergence stage), (T2: at planting + stem elongation + in ear emergence stage), (T3: at planting + stem elongation + ear emergence stage). Results showed that dry matter remobilization rate from stem, contribution of dry matter remobilization from shoot organs at grain yield, components of grain growth, nitrogen use efficiency, yield and yield components were significantly affected by experimental factors. Maximum of dry matter remobilization from stem and shoot organs was obtained in control treatment and the least of it were obtained in higher nitrogen rates as T1. The highest rate and grain filling period, yield and yield components was obtained in higher nitrogen rates as T1. Maximum of nitrogen use efficiency (31.45 kg/kg) was obtained in application of 60 kg N.ha 1 as T1 and the least of it (23.72 kg/kg) was obtained in higher nitrogen rates as T0. Based on the results, it was concluded that application of 180 kg N ha-1 as T1 can be recommended for profitable barley production in the study area.