Forage crops nitrogen use efficiency changes under drought conditions

Ensuring sustainable agriculture and food security is one of the biggest challenges under changing climate. The frequency and severity of droughts is increasing as a result of climate change. These extreme events may lead to decreased forage crop productivity and financial incomes. Forage crop productivity strongly depends on plants nitrogen use efficiency which in turn may be affected by changed climate conditions. The aim of the study was to examine the influence of drought on the growth and nitrogen use efficiency of alfalfa (Medicago sativa L.) and festulolium (Festulolium loliaceum (Huds.) P.Fourn.) at different rates of nitrogen (N) supply (background, 60 and 90 kg N ha-1). Alfalfa and festulolium, grown in a climate-controlled glasshouse, were subjected to short-term drought (7 days) under ambient CO2 (400 ppm) concentration. After the cease of stress, plants were rehydrated and left for 7 days to recover under control conditions. The growth (aboveground and belowground biomass, height), plant N content, nitrogen use efficiency (uptake (NupE), use (NUE) and utilization (NutE)) of both plant species were evaluated. Drought had an adverse effect on N accumulation and N uptake, use and utilization efficiency in alfalfa and festulolium. Additional N supply reduced efficiency of N uptake and use.