Can we get more crop per drop?
My caffeine addiction comes in the form of tea. When I’m being especially productive, I’m up to three or four big cups a day. Add in a few trips to the drinking fountain and some glasses of water … and it seems like I consume a lot of H2O every day! All in all, I’m told I probably consume around 1,000 liters of water per year. This seems huge, right? Yet it turns out that the rain and irrigation water that goes into our food is much, much more than 1,000 liters … think 500,000 liters! And that’s for a vegetarian. Carnivores have an even bigger water footprint. So it’s clear that we need to be paying attention to our food if we are concerned about water. But where do we use water for agriculture? And can we use this water more efficiently?
Kate Brauman, Global Landscapes Initiative postdoctoral fellow at IonE, laid bare the global patterns of agricultural water use with new state-of-the-art crop water use data at this week’s Frontiers in the Environment lecture. Kate found that the major cereal crops (maize, wheat, and rice) are the big rainwater consumers across much of the globe, but in arid areas drought-tolerant millet and sorghum dominate rainwater consumption. In irrigated systems, just one crop – rice – consumes a somewhat shocking 70% (!) of global irrigation water.
In addition to laying out consumption patterns by crop, Kate explored the possible impacts of improving the ratio of production to water use in arid areas. Huge variations exist in these efficiency levels, so bringing up the most water-inefficient areas to the 20th percentile level of efficiency can mean big increases in crop production. Such a boost for African maize could immediately increase crop production by 12%. Big opportunities also exist in NE Brazil, Southern India, and Eastern Europe.
Kate ended with an apt metaphor for the complexities in water management. She contrasted our usual simple view of tradeoffs – visualized as a balancing see-saw – with a balancing pogo ball! These are complex, multidimensional issues … and I’m thrilled that Kate is doing such an excellent job exploring them. Check out the archived video if you missed the talk!