Tarbiat Modares University Journal of Agricultural Science and Technology 1680-7073 20 7 2018 12 01 Impact of Split Application of Different N-Fertilizer Sources on Weed Growth, Safflower Yield, and Nitrogen Use Efficiency اثر تقسیط منابع کود نیتروژن بر رشد علف های هرز، عملکرد گلرنگ و کارایی استفاده از نیتروژن 1455 1466 16235 EN R. Moradi Talebbeigi Department of Crop Production and Plant Breeding, School of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran. S. A. Kazemeini Department of Crop Production and Plant Breeding, School of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran. H. Ghadiri Department of Crop Production and Plant Breeding, School of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran. Journal Article A 2-year field experiment was conducted to evaluate the effect of N sources [Ammonium Nitrate (AN), Ammonium Sulfate (AS), Sulfur Coated Urea (SCU), and Urea (U)] and split application ((1/4,3/4,0), (1/3,1/3,1/3), (1/2,1/2,0), and (1/3,2/3,0)) on weed growth, safflower (Carthamus tinctorius L.) yield, and N Use Efficiency (NUE), using a split split-plot design with three replications, at the Experimental Research Station of Shiraz University, in 2015 and 2016. In weedy plots, applying AN-fertilizer in a split pattern of 1/2,1/2,0 (applying half of the N at sowing time and the rest at stem elongation) increased weed infestation. This treatment enhanced total weed N Uptake Efficiency (NUpE) up to 5% compared to U-fertilizer and similar split pattern. In weed free plots, the highest seed and oil yields (3303.52 and 753.09 kg ha-1, respectively) were achieved by AN- and U-fertilizers in a split pattern of 1/2,1/2,0. Applying AN fertilizer and split patterns of 1/3,2/3,0 (one third of N at sowing and two thirds at stem elongation) and 1/4,3/4,0 (one quarter of N at sowing and three quarters at stem elongation) maximized safflower NUpE (0.78 kg kg-1). Applying U fertilizer and split pattern of 1/2,1/2,0 increased safflower ability to compete vs. weeds up to 20% compared to AN-fertilizer. Overall, in order to improve safflower yield and NUE and control weed, applying U-fertilizer and split application of 1/3,2/3,0 or 1/4,3/4,0 can be suggested as a component of integrated weed management programs.

https://jast.modares.ac.ir/article_16235_0a3d76a1b1aa57cb255bc897ac3254a2.pdf