Very little information is available for Mediterranean areas about the soil N dynamics and crop N use efficiency during the transition phase from conventional tillage (CT) to no-tillage (NT). Hence, a 2-yr experiment was conducted under semiarid Mediterranean conditions in three sites to study how soil N dynamics, crop N uptake, grain yield, and N use efficiency vary with N-fertilization rate and crop genotype in the switch year from CT to NT. Treatments consisted of two tillage systems (CT and NT), five N-fertilization rates (0, 40, 80, 120, and 160 kg N ha⁻¹), and two durum wheat (Triticum durum Desf.) genotypes (one modern variety and one old landrace). Irrespective of the genotype, NT reduced compared to CT both wheat N uptake and grain yield under low soil N availability. The greater soil N supply under CT was the main reason for this outcome, so much so that the differences between CT and NT for these traits gradually decreased with the increase of N-fertilization rate, practically disappearing at 80 kg N ha⁻¹). The analysis of the N use efficiency components corroborated this hypothesis showing clearly that the yield advantage observed in CT depended mainly on the increase in N supply in soil under CT than NT condition. The two wheat genotypes responded similarly to varying soil tillage system. However, the adverse effects of NT practice were more evident in the modern variety than the old landrace. This study ultimately indicates that in the Mediterranean areas the switch year from CT to NT regime is rather delicate. Given that the lack of soil cultivation considerably reduces the soil N availability, hence, using NT technique alone as a substitute for CT is not agronomically feasible. Instead, an optimal application of NT is achievable by acting simultaneously on other factors of the cropping management, particularly the N-fertilization strategy, to maximize the crop N use efficiency and increase crop yield, which are essential requirements for a more sustainable agriculture.

Data availability

Data will be made available under agreement.

中文翻译：

---

常规耕作与免耕：地中海环境中生长的对比硬粒小麦基因型的氮利用效率成分分析

在从常规耕作 (CT) 到免耕 (NT) 的过渡阶段，关于地中海地区土壤氮动态和作物氮利用效率的信息很少。因此，在三个地点的半干旱地中海条件下进行了一项为期 2 年的实验，以研究从 CT 到 CT 的转换年土壤氮动态、作物吸氮量、谷物产量和氮利用效率如何随施氮量和作物基因型而变化新台币。处理包括两种耕作系统（CT 和 NT）、五种施氮量（0、40、80、120 和 160 kg N ha ^-1）和两种硬粒小麦（Triticum durumDesf.) 基因型（一种现代品种和一种古老的地方品种）。无论基因型如何，在低土壤氮有效性下，与 CT 相比，NT 降低了小麦的 N 吸收和谷物产量。CT 下更大的土壤 N 供应是造成这一结果的主要原因，以至于 CT 和 NT 在这些性状上的差异随着施氮量的增加而逐渐减小，在 80 kg N ha -1 时几乎^消失). 对氮利用效率成分的分析证实了这一假设，清楚地表明在 CT 中观察到的产量优势主要取决于 CT 条件下土壤中 N 供应量的增加，而不是 NT 条件。两种小麦基因型对不同土壤耕作制度的反应相似。然而，NT 实践的不利影响在现代品种中比在古老的地方品种中更为明显。这项研究最终表明，在地中海地区，从 CT 到 NT 制度的转换年份相当微妙。鉴于缺乏土壤耕作大大降低了土壤氮的有效性，因此，单独使用 NT 技术替代 CT 在农学上是不可行的。相反，通过同时作用于作物管理的其他因素，特别是氮肥施肥策略，可以实现 NT 的最佳应用，

数据可用性

数据将根据协议提供。