Analyse de l'efficience de l'utilisation de l'azote, du blé dur cultivé en zone semi-aride

Abstract

The objective of this study is analyzing the effect of nitrogen fertilization and its use efficiency on the grains yield and its components, as well as the protein content in local variety of durum wheat (Boussalem), grown in semi-arid area (Sétif).. The experiment were conducted over two years (2017 and 2018). The wheat crop was subjected to seven increasing nitrogen regimes (0-100-110-120-130-140 and 150 NU / ha) applied in two fractions. Statistical analyzes show a nitrogen effect on yield, its components and protein levels. During the rainy year, the yield range was 34.8 to 69.1Qx / ha and a protein level ranged from 11.1 to 12.4%. The highest values were achieved with the 150UN / ha dose. In the dry year, yields ranged from 6.4 to 12.5Qx / ha recorded under the 130UN /ha dose and a protein level of 12.4 to 17.5% with the 120UN / ha dose. The most important determinant of yield is the number of kernels but with a negative effect on the protein level. The effect of nitrogen on agronomic nitrogen use efficiency (NUEA = 15.29kgG / kgN) is insignificant except on the apparent nitrogen recovery efficiency (CAU = 12.14 to 72.24%) under the dose 150UN/ha. The latter who affected the other indicators; it has increased the NUEA is therefore increased the grains yield. The nitrogen harvest index (NHI) increases the level of protein but the agro-physiological nitrogen use efficiency (NUEAP) decreases the NHI and consequently decreases the level of proteins. Key words: Durum wheat, agronomic nitrogen use efficiency, apparent nitrogen recovery efficiency, nitrogen dose, semi-arid area, grains yield.