CO2 uptake by plants (photosynthesis) and leaf water loss (controlled by the stomata) underpin the agricultural water use efficiency tradeoff.  Thus research addressing the mechanisms by which leaf photosynthesis and stomata respond to the environment can form the basis for understanding the limits to changing WUE in crops. It is our goal to:

  1. establish a physiological WUE envelope within which it is practical to manipulate crop water use and productivity,
  2. develop a basic understanding of physiology underlying photosynthesis and water loss,
  3. investigate the physiological consequences of changing WUE,
  4. perform scaling exercises to verify that leaf or plant physiology affects whole plant and canopy processes, and
  5. establish practical screening or management for variation in the components of WUE.

The possibilities for changing whole crop WUE are relatively limited by the physiological tradeoff between photosynthesis and transpiration. Our contention is that the goal of improving WUE will only be practically met through concerted efforts in two fields: reducing stomatal water loss combined with increases in photosynthetic capacity. However these are only useful if done with field-scale validations testing whether micro-level processes scale up to the crop-level. This goal will only be possible through a better understanding of basic photosynthetic and stomatal physiology.

arboretum poster


food supply graph

This graph shows the historical land use and yield of world agriculture (data from Foley et al. 2011), with the curves representing combinations leading to equal total production. What may be surprising is that the majority of the large historical increase in production is due to more food being produced per unit land area, and we may expect that trend to be important for the future when the world food demand will be much larger (like options A and B). This means that we, as scientists and farmers, will have to increase crop yields considerably in the next 40 years, and do this with the same or less resources, particularly water.

What makes this exciting is that if you are in your twenties or thirties, you have the opportunity to see and develop our solutions to this problem over the course of your career.