Water productivity benchmarks: The case of maize and soybean in Nebraska

• Published in: Agricultural water management 2020-05, Vol.234, p.106122, Article 106122
• Main Authors: Mekonnen, Mesfin M., Hoekstra, Arjen Y., Neale, Christopher M.U., Ray, Chittaranjan, Yang, Haishun S.
• Format: Article
• Language: English
• Subjects: Benchmarks; Spatial and temporal variability; Water footprint; Water productivity gaps; Yield gaps
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/j.agwat.2020.106122

•Water productivity (WP) of maize and soybean varies across Nebraska.•Water productivity of maize and soybean has improved between 1990 and 2014.•Water productivity of maize and soybean can still be increased.•Setting WP benchmarks will help to reduce the water footprint of crop production. Water productivity benchmarks for irrigated and rainfed agriculture will provide relevant information to manage scarce water resources and control groundwater level decline. We analyse the temporal and spatial variation of the water productivity (WP) of maize and soybean in Nebraska, with WP defined as harvested crop weight per total evapotraspiration. The results show that WP of both maize and soybean increase from west to east within Nebraska and have increased over the last 25 years, mainly due to the increase in crop yields (land productivity). We derive WP benchmarks for each crop per climate zone. Increasing actual WPs in the state to benchmark levels will increase yields by 21 % for maize and by 19 % for soybean. The WP benchmark levels for the two crops presented here will help formulating targets for closing water productivity gaps and improving the sustainability of water use in the state.