نویسندگان
1 استادیار بخش تحقیقات خاک و آب مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی کردستان، سازمان تحقیقات، آموزش و ترویج کشاورزی، سنندج، ایران
2 استاد گروه خاکشناسی دانشکده کشاورزی دانشگاه زنجان
3 کارشناس پژوهشکده کشاورزی هستهای، پژوهشگاه علوم و فنون هستهای
4 استادیار موسسه تحقیقات کشاورزی دیم کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، مراغه، ایران
5 دانشیار گروه زراعت دانشکده کشاورزی دانشگاه کردستان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In order to study the effects of nitrogen application management on nitrogen use efficiency (NUE) in rainfed wheat, a field experiment was conducted as split plot experiment, based on randomized complete block design, included five rates of nitrogen (0, 30, 60, 90 and 120 kgN ha-1) using urea (labeled with 8% and 6% atom excess 15N) as the main plot in Kurdistan province during 2012-13. The sub-plots were consisted of three application times such as T1: Total nitrogen in the fall, T2: 2/3 nitrogen in the fall + 1/3 nitrogen in the spring, and T3:1/2 nitrogen in the fall + 1/2 nitrogen in the spring (at tillering stage). The isotopic (15N) technique was applied to estimate fertilizer N recovery efficiency based on recovery of labeled urea-15N in the aboveground portion of wheat (grain and straw). Results showed that the effects of nitrogen timing on grain yield and total N uptake were significant at 5% level. The effect of nitrogen rates were significant on grain yield, total N uptake,fertilizer N uptake, fraction of N in the plant derived from the 15N-labeled fertilizer (Ndff%), and NUE of 15N (p<0.05), and grain protein content (p<0.05). Compared with the check, nitrogen timing increased grain yield and grain protein content by 35% and 33%, respectively. By increasing nitrogen from 30 to 120 kg.ha-1,fraction of Ndff % was increased from 11% to 39%, corresponding to NUE range from 21% to 28%. The maximum NUE (33%) was obtained in 90 kg N.ha-1. About 70% of nitrogen uptake in the aboveground portion of wheat was belonged to grain wheat. Optimum grain yield with maximum NUE in different nitrogen application timings of T1, T2 and T3 were estimated at 69, 60, and 51 kg N.ha-1, respectively.
کلیدواژهها [English]