Nitrogen Fertilization of Durum Wheat Cultivars in the Rainfed Area of Morocco: Biomass, Yield, and Quality Considerations

Nitrogen is the dominant fertilizer element required for cereals in Morocco. While fertilization is less common in the semi-arid (250-450 mm) cereal belt than at higher rainfall zones, the benefits in terms of yield increases and economics are potentially important. However, research has been focused mainly on bread wheat (Triticum aestivum L), notwithstanding the importance of durum wheat (T. Turgidum var durum L). This on-farm trial in a shallow soil (Petrocalcic Palexeroll) in the dryland Chaouia area of south-central Morocco evaluated the impact of N (0, 30, 60, 90, 120 kg N/ha) in five durum cultivars (Kyperounda or 2777, Marzak, Massa, Cocorit, Karim). Data were influenced by both N and cultivar, with no interaction between them. Nitrogen significantly increased biomass and grain yields up to 90 kg/ha; it had little effect on either grain N concentration, except at the highest level (120 kg/ha), or kernel weight, but tended to decrease the percentage of "yellow berry". Yields were significantly higher for Kyperounda, Marzak, and Karim than either Cocorit or Massa. Grain N and kernel weight were little influenced by cultivar, but the incidence of "yellow berry" varied with the cultivar. While recognizing cultivar differences, the study highlights the role of N for yield and quality components of durum wheat.