Plant NUE (Nutrient use efficiency) is inherently complex with each step (including N uptake, translocation, assimilation, and remobilization) governed by multiple interacting genetic and environmental factors. Therefore, physiology and agronomy approach to improve NUE, are a major objective in the future. The experiment was carried out at the Environmental Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during the Boro season in 2018 to determine the effect of nitrogen application on the growth and yield of BRRI dhan28 and to calculate the agronomic use efficiency of nitrogen under nitrogenous fertilizer application. The experiment was laid out in a randomized complete block design with three replications. There were four treatments based on N application rates: N0: 0 kg N ha-1 (T1), N75: 75 kg N ha-1 (T2), N150: 150 kg N ha-1 (T3), and N250: 250 kg N ha-1 (T4). Results found that all the treatments significantly increased the LAI over control. LAI was increased up to the growth stage and declined at harvest (110 DAT). The crop growth rate was higher (19.30 CGR g m-2 day-1) in T4 and the Crop growth rate was lower (1.95 CGR g m-2 day-1) in T1. T4 (250 kg N ha-1) treatment performed statistically significant in terms of yield and yield contributing characters. The highest grain yield (6.50-ton ha-1) was obtained in the treatment T4 (250 kg N ha-1) and the lowest grain yield (3.38-ton ha-1) was obtained in the treatment T1 (control). Highest NUE was obtained in T2 (16.19%). Finally, it can be concluded that T4 (250 kg N ha-1) treatment performed better in terms of growth analysis and yield and yield contributing characters.
Key words: Keywords: Nitrogen use efficiency (NUE), Leaf area index (LAI), Crop growth rate (CGR), BRRI dhan 28, Nitrogenous fertilizer
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