عنوان مقاله [English]
In order to study the effect of N rate and plant density on grain yield and N use efficiency of blessed thistle, a field study was carried out in a randomized complete block design with factorial arrangement of treatments in three replications at Research Field of Tarbiat Modares University in 2013 and 2014 growing seasons. Treatments comprised of four pure N rates (0, 50, 100 and 150 kg N ha-1) from urea source and five plant densities (5, 10, 15, 20 and 25 plants m-2). The main effects of nitrogen and plant density were significant for grain yield, NUE, plant height, SPAD value, root to shoot weight ratio and N content of grain. Increasing N rates increased grain yield, SPAD value, plant height and grain N, but agronomic efficiency, N recovery and utilization were decreased by increasing of N rate; Higher densities resulted in decreased grain yield and chlorophyll index, while improved NUE throughout increment of root to shoot weight ratio and plant height. Novel findings of this study could be used for N management.
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