Triticale forage crop quality as affected by water stress and nitrogen biofertilizer in an arid climate

Understanding the interactive effect of water and nitrogen (N) availability is a crucial issue for stabilizing cereal forage production in the arid areas. A two-year side by side experiment (2015-2016 and 2016-2017 growing seasons) was carried out under different N sources and water regimes in a typical arid environment (Darab, Iran) to evaluate the forage quality of triticale (×Triticosecale Wittmack) crop.There were two irrigation regimes [normal irrigation (IRN) and cutting off irrigation after crop anthesis stage (IRMD)]. Rain-fed treatment (IR0) was included in the second year. Three N sources including Azospirillum brasilense (biofertilizer, Bio), Azospirillum brasilense + 75 kg N ha-1 as urea (Bio + N75), 150 kg N ha-1 as urea (N150) and unfertilized plots (N0 ascontrol) were used. Water stress decreased leaf-stem (L/S) ratio, dry mater (DM) and dry matter digestibility (DMD) and increased crude forage protein (CP), neutral detergent fiber (NDF) and ash contents. However, the effect of water stress on forage ash, DMD, ADF contents, L/S ratio (in 2015-2016 growing season) and CP content depended on N sources. In Bio + N75, triticale forage had the highest CP content, DMD, ash and L/S ratio (in 2015-2016 growing season) and the lowest ADF compared with the other N sources under water stress conditions. According to the results of this study, it can be suggested that the integration of biofertilizer and chemical N fertilizer be successfully used to increase the quality of triticale forage under deficit irrigation regimes in sustainable farming systems in arid conditions.