Critical nitrogen dilution curve and dry matter production parameters for several Mediterranean vegetables

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