Durum Wheat Yield and N Uptake as Affected by N Source, Timing, and Rate in Two Mediterranean Environments

In nitrate vulnerable zones (NVZs), site-specific techniques are needed to match N availability with durum wheat (Triticum turgidum subsp. Desf.) requirements. Enhanced-efficiency fertilizers can improve efficient supply and reduce leaching, contributing sustainable agriculture. Two-year field experiments were carried out at two Mediterranean in Central Italy (Pisa Arezzo) study the effects of nitrogen sources, timings, application rates. The trial compared: (i) three sources for first topdressing (urea, methylene urea, urea nitrification inhibitor DMPP); (ii) stages (1st tiller visible—BBCH21 1st node detectable—BBCH31); (iii) rates: one based on crop requirements (Optimal—NO), other action programme prescriptions NVZs (Action Programme—NAP). Grain yield components determined, together uptake. results showed that: grain biomass production reduced NAP both locations; performed better than slow-release fertilizers; best time depended source location: Pisa, enhanced-efficiency achieved higher yields when applied earliest, while opposite was true; Arezzo different similar performances between timings. Different behaviors localities could be related diverse patterns temperatures rainfall. Thus, optimal fertilization strategies would seem vary according environmental conditions.