Nitrogen Use Efficiency in Durum Wheat (Triticum durum Desf.) Grown under Semiarid Conditions in Algeria

Abstract

The proper and sustainable management of nitrogen fertilization is one of the most common problems of cereal cultivation in semiarid regions, which are characterized by a wide variability in climatic conditions. The current work was conducted to evaluate the effects of nitrogen fertilization on the agronomic and economic aspects of durum wheat cultivated under rainfed semiarid conditions in Algeria and to determine the most efficient nitrogen use efficiency (NUE) among four genotypes that are widespread in the country (tall and short, old and modern genotypes). The four genotypes, Bousselam, MBB, Megress, and GTAdur, were investigated under four nitrogen rates from 0 to 120 kg N ha−1 during three cropping seasons (2016 to 2018). The results indicate that the total nitrogen uptake at maturity (NM), nitrogen uptake by grain (NG), nitrogen harvest index (NHI), NUE and its components, such as nitrogen uptake efficiency (NUpE) and nitrogen utilization efficiency (NUtE), were significantly affected by year, genotype, and nitrogen level. From this study, it appears that higher nitrogen rates improved NM and NG. However, no effects on either grain yield or marginal net return (MNR) were observed; conversely, increased nitrogen levels produced a 13% reduction in the economic return. In other words, in the North African environment, the response to nitrogen is more evident in quality than in yield, which in turn is dependent on the yearly weather conditions and cultivated genotypes. Moreover, nitrogen negatively affected NUE and its components (NUpE, NUtE). On average, NUE displayed low values (14.77 kg kg−1), mostly irregular and highly dependent on weather conditions; in the best year, it did not exceed 60% (19.87 kg kg−1) of the global average value of 33 kg kg−1. Moreover, the modern genotypes Megress (tall) and GTAdur (short) showed the best capacity to tolerate different nitrogen conditions and water shortages, providing relatively superior yields, as well as more effective N use from fertilizers and the soil than the other two genotypes.

Nitrogen Use Efficiency in Bread Wheat Across Environments

“…Bektash and Naes (2016) found significant differences among the different bread wheat lines for biological yield while studying several genotypes, with the wheat line 12-S recorded with the highest grain yield (16.96 t ha -1 ). Benchelali et al (2022) found in their study of four durum wheat (Triticum durum Desf.) genotypes with four nitrogen levels (0, 40, 80, and 120 kg N ha -1 ) over three seasons, the highest NUE (19.06) appeared at fertilizer level 40 kg N ha -1 , and the highest fertilizer level (120 kg N ha -1 ) emerged with the less NUE value (10.91).…”