Inadequate nitrogen fertilizing practices lead to low nitrogen uptake efficiency (NUE), which increases water NO₃⁻ pollution, as well as N₂O emissions to the atmosphere. In order to increase the NUE and decrease the N losses as NO₃⁻ and N₂O from the soil-plant system, accurate data about optimum crop N concentrations and dry matter production throughout the growing season are still needed for many vegetables typically grown under Mediterranean climate. For this reason, several N fertilization trials were set up for globe artichoke, carrot, cauliflower, chard, chinese cabbage, early potato, leek, lettuce, onion, red cabbage, romanesco, and spinach, under the semiarid Mediterranean conditions of the Valencian Community (Eastern Spain) during several years. The fresh and dry matter weight (W), as well as the nitrogen concentration in the dry matter (%N) in both the marketable and non-marketable crop parts, was measured between 3 and 7 times throughout their respective growing seasons. The a and b coefficients of the average N dilution curve (%N = a W ^− b), for which all %N and W data were used, and the critical N dilution curve (%N_c = a W_c^−b), for which only the minimun %N for maximum W data were used if available, in addition to the dry/fresh yield matter ratio (DM) and the harvest index (HI), were calculated for all these crops. No significant differences were observed between the average and critical N dilution curve coefficients in this work. Interestingly, the coefficients of both N dilution curves differed from the ones found in the literature with the exception of those obtained for similar cultivars, e.g., early potatoes, and under similar climatic conditions, i.e., Mediterranean. Besides, there were neither differences of DM and HI among the several N fertilization treatments. Therefore, due to the absence of changes in the N dilution curve and dry matter production coefficients for the different N supplies, all these parameters were estimated on the basis of the whole dataset, i.e., regardless of the N input. The use of the critical nitrogen dilution curve coefficients and dry matter production parameters presented in this work should contribute to better fit the N fertilizer additions to N demands of these vegetables under Mediterranean conditions, mainly, by their use through simulation models. Therefore, the NUE in horticulture should increase and the N losses as NO₃⁻ to inland and sea waters in these environments, and as N₂O to the atmosphere should decrease.

施氮量不足会导致氮吸收效率 (NUE) 降低，从而增加水 NO ₃ ^-污染以及向大气排放 N ₂ O。为了增加 NUE 并减少作为 NO ₃ ^-和 N _{2的 N 损失}对于通常在地中海气候下种植的许多蔬菜，仍然需要来自土壤-植物系统的 O ，关于整个生长季节的最佳作物 N 浓度和干物质产量的准确数据。出于这个原因，在巴伦西亚社区的半干旱地中海条件下，为朝鲜蓟、胡萝卜、花椰菜、甜菜、大白菜、早熟马铃薯、韭菜、生菜、洋葱、红甘蓝、罗马菜和菠菜建立了几次氮肥试验。 （西班牙东部）几年。可销售和非可销售作物部分的新鲜和干物质重量 ( W ) 以及干物质中的氮浓度 (% N ) 在它们各自的生长季节测量了 3 到 7 次。一个和_b平均 N 稀释曲线的系数 (% N  =  a W  ^{-  b} )，其中使用了所有 % N和W数据，以及临界 N 稀释曲线 (% N _c  =  a W _c ^{- b} )，其中仅除了干/鲜产量物质比 ( DM )和收获指数( HI)，对所有这些作物进行了计算。在这项工作中，平均和临界 N 稀释曲线系数之间没有观察到显着差异。有趣的是，这两条 N 稀释曲线的系数与文献中的系数不同，除了从相似品种（例如早熟马铃薯）和相似气候条件下（即地中海）获得的系数。此外， DM和HI也没有差异在几种 N 施肥处理中。因此，由于不同 N 供应的 N 稀释曲线和干物质生产系数没有变化，所有这些参数都是在整个数据集的基础上估计的，即不考虑 N 输入。使用本工作中提出的临界氮稀释曲线系数和干物质生产参数应有助于更好地适应地中海条件下这些蔬菜的氮肥添加量，主要是通过模拟模型的使用。因此，园艺中的 NUE 应该增加，而在这些环境中，作为 NO ₃ ^-向内陆和海水中的 N 损失以及作为 N ₂ O 向大气中的损失应该减少。