Description

Global population is predicted to reach 9.1 billion by 2050. To support this growing population, food production and fresh water availability will need to increase by 70 and 55%, respectively. At the same time, water availability and water use patterns are likely to change in coming years, as precipitation patterns shift and global temperatures from increase from 1 to 2.5°C in the next 50 years and more extreme drought and heat waves are expected, which together will alter the vapor pressure driving force, soil water availability, water use patterns and plant productivity.

Agriculture currently accounts for nearly 70% of global fresh water use. Unlocking the interaction of plants with soil and the atmosphere is essential to advance water use efficiency research. To achieve “more crop per drop”, a combination of agronomic, physiological, biotechnological/genetic and engineering solutions must be employed. Plant trait selection for increased water use efficiency (WUE) is expected to shift ecosystem demographics in forest and grassland systems, while novel agronomic systems, engineering and biotechnological/genetic advances will be required for increasing crop WUE to sustain and increase production. Isotope discrimination techniques, imaging tools such as microscopy, chlorophyll fluorescence, infrared thermography and remote sensing, and direct assessment of water extraction, root uptake, xylem transport and stomatal release via sensors, gas exchange and eddy covariance techniques all provide key insight into WUE and photosynthetic performance. Advances in molecular biology can link genes to traits, and allow for novel assemblages of different C3, C4 and CAM photosynthetic systems that have potential to significantly boost WUE in crops. Improved crop/soil water management practices are capturing more water, improving biomass water ratio and harvest index. Significantly, we are now seeing accelerated translation of basic research to improve crop performance and agricultural practice. In addition to potential increases in crop yield, fundamental understanding of WUE across scales can be used to inform and improve plant, ecosystem and terrestrial biosphere models.

This Research Topic will focus broadly on our current understanding and characterization of WUE, evidence for changing WUE in response to abiotic (or biotic) drivers (e.g., trait selection, phenotypic plasticity) and novel management and molecular biology approaches. We welcome observational, empirical and modeling research results or perspectives across terrestrial ecosystems, including managed agronomic systems, and field and laboratory studies that encompass multiple domains of research across scales (genetics, ecophysiology, agronomy, engineering, remote sensing) and reflects the challenges and complexities of this topic. In particular, we welcome manuscripts on the following subjects:
• WUE: Concepts, definitions and approaches to assess WUE across spatial and temporal scales
• Assessment of plant traits associated with WUE (roots, leaves, phenology, biochemistry)
• Scaling-up or modeling WUE from molecular, to plant, to ecosystem scales
• Novel experimental and modelling approaches for quantifying root growth and water uptake
• Improved soil, crop and water management techniques to improve water use
• Water-use efficiency in arid or water-limited environments and impacts of a changing climate
• Physiological, molecular, biochemical, genetics and plant breeding advances in improving water use

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