Under dryland systems of the Mediterranean basin, water management is widely recognised critical for improving grain yield. It has been proposed that nitrogen (N) fertilisation may be a tool to increase grain yield by increasing water use efficiency. We tested in a multilocation-multiyear study in four different areas of the Mediterranean Basin if durum wheat and barley may respond positively to N fertilisation under rainfed cultivation. The study involved 16 experiments including different genotypes of durum wheat and barley sown at Morocco, Jordan, North-eastern Spain, and Southern Italy, with different nitrogen doses applied at sowing or early in crop development from 2003/04–2007/08 growing seasons. Grain yield increased 26% in average for years, locations and species compared with their respective unfertilised controls. The increased yield in response to N fertilisation was noticeable under low (< 2 Mg ha⁻¹) and under high yield potential cases (> 5 Mg ha⁻¹). There were only exceptional cases with slightly negative or no responses to N fertilisation. Grain number per unit area, and not grain weight, was the main component related to grain yield. Also, total biomass at maturity was closely related to grain yield. Barley and durum wheat responded similarly to N fertilisation.

在地中海盆地的旱地系统中，水资源管理被广泛认为对提高粮食产量至关重要。有人提出，氮 (N) 施肥可能是通过提高水分利用效率来提高粮食产量的一种工具。我们在地中海盆地四个不同地区的多地点多年研究中测试了硬质小麦和大麦是否可能对雨养栽培下的氮肥产生积极反应。该研究涉及 16 项实验，包括在摩洛哥、约旦、西班牙东北部和意大利南部播种的不同基因型的硬粒小麦和大麦，从 2003/04 到 2007/08 生长季节，在播种或作物发育早期施用了不同的氮剂量. 与各自未施肥的对照相比，年份、地点和物种的谷物产量平均增加了 26%。^-1 ) 和高产潜力情况下 (> 5 Mg ha ^-1 )。只有少数例外情况对施氮肥有轻微的负面反应或没有反应。单位面积粒数而非粒重是影响粮食产量的主要因素。此外，成熟时的总生物量与谷物产量密切相关。大麦和硬粒小麦对氮肥的反应相似。