Effects of climate change on the nitrogen balance of a grassland ecosystem

Grassland is one of the most abundant biomes in the world and important for a variety of ecosystem services. Global climate change is causing a significant increase in temperature and a change in the seasonal distribution of precipitation. The resulting variation in nitrogen turnover is site-specific and long-term experiments are needed to study these changes.
The objective of this study was to investigate changing environmental variables on nitrogen cycling and water use efficiency of an extensively managed grassland site in a low mountain range. Data from the TERENO-SOILCan lysimeter network at the Rollesbroich and Selhausen sites were used. In a "time for space" approach, a total of nine lysimeters were filled at the initial Rollesbroich site and three of these lysimeters were moved to the Selhausen site. Compared to the initial site, the climate in Selhausen is warmer and drier, according to climate predictions.
The results show that climate change may increase the risk of gaseous nitrogen emissions, but that low nitrogen inputs from an extensively used grassland result in only low nitrogen discharges via leachate. In addition, water use efficiency and nitrogen nutrition index will decrease if the crop suffers from water stress, making the grassland more sensitive to drought.