Approaches for increasing nitrogen and water use efficiency simultaneously

• Interaction between water- and nitrogen-use efficiency is common in cropping systems.
• Simultaneous improvement of water and nitrogen use affects their efficiency positively.
• Management practices are crucial to increase water and nitrogen use efficiency.
• New technologies may increase water- and nitrogen-use efficiency in cropping systems.

Enhancement of water and nitrogen use efficiency simultaneously may provide advantages over optimization of water and nitrogen inputs separately. In addition, water is the driver of the main environmental problems caused by excessive nitrogen use, such as nitrate contamination of water bodies or increasing emissions of the greenhouse gas nitrous oxide. Therefore, management practices oriented towards reducing nitrogen losses and maintaining farm productivity should rely on optimizing nitrogen and water inputs at the same time. This manuscript identifies agricultural systems with strong interactions between water- and nitrogen-use efficiency. Measurements and approaches for applying new technologies to increasing nitrogen and water efficiency simultaneously are discussed.