Efficiency of two nitrogen fertilizers applied in different phenological stages on a winter bread wheat (Triticum aestivum L.)
1993
Mellado Z, Mario (Instituto de Investigaciones Agropecuarias, Chillan (Chile). Estacion Experimental Quilamapu)
A field experiment was carried out during four successive crop seasons, 1988-1991, at the Quilamapu Experiment Station (INIA), Chile, to evaluate the efficiency of nitrogen use by a winter bread wheat, when this nutrient was applied as Chilean nitrate or as urea, at different phenological stages during growth cycle. The trials were set up under irrigation, in a split plot design, involving application date as treatments and the nitrogen fertilizers as subtreatments. Both fertilizers were broadcasted in a single application of 150 kg N/ha per subtreatment, on the soil surface every 30 days since sowing until heading. Evaluations were: grain yield, yield components, phytomass and nitrogen content of the grain and straw. The most important conclusions are: - Chilean nitrate and urea applied at different phenological stages in a winter bread wheat, had the same performance. - Early nitrogen applications from sowing to initial tillering, or late nitrogen application (spike emergence) negatively affect the grain production, N extraction and N recovery by the wheat plant. - The highest values of grain yield and grain production efficiency were obtained when all the N rate was applied between tillering and jointing. - Total rainfall between sowing time and the fertilizer application dates related to the leaching of nitrogen, might explain the variations in the nitrogen recovery capacity by the wheat plant
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