Climate Change

When They Said They Wanted to Rethink Agriculture, They Meant It

November 6, 2017

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Farmer Doug Thomas holds rice © Drew Kelly for The Nature Conservancy

NatureNet Science Fellows Update

Figuring out how the world is going to feed 7 billion people (and counting) in a time of changing climate, richer diets, and already over-burdened land and water resources is going to require wholesale rethinking of global agricultural practices.

Clearly, solving such 21st century challenges is not for people with faint hearts or imaginations, which means it’s a challenge tailor made for Conservancy NatureNet Science Fellows like Kyle Davis.

Davis, who is a second-year fellow at Columbia University, is using his two-year applied research fellowship to develop solutions for one of the key challenges to sustainable agricultural intensification around the world – how to grow more crops with less water without expanding agriculture’s already sprawling footprint.

“A big problem,” notes Davis, “is that the current distribution of crops around the world doesn’t maximize yields or minimize water use. So we [Davis and colleagues] set out to completely rethink agriculture to see if there was a better way.”

Turns out, there is. In fact, it’s a better way so intriguing that Davis and his colleagues recently published their findings in Nature Geoscience. (Quick spoiler alert: when they said they wanted to “rethink agriculture,” they meant it.) 

What Does it Mean to ReThink Agriculture?

“Presumably, agricultural systems have been motivated by the need to feed more people and to remain profitable,” says Davis, “and this suggests that environmental impacts of food production – like water use for irrigation – only receive secondary consideration in a farmer’s decision of what crop to plant. So we wondered: Is it possible to use crops with lower water needs without affecting the amount of production?”

Irrigation sprinkler © Ken Geiger/TNC

Davis and his colleagues evaluated 14 major food crops, like maize, rice, soybeans, and wheat, and “identified differences between current crop distributions and where they could most suitably be planted on existing rain-fed and irrigated croplands.” Then they started “redistributing crops across currently cultivated lands” using their own custom-built optimization algorithm.

What if they replaced sugar beets and millets in western Russia with rainfed sorghum, tubers, soybeans and wheat? Or if irrigated maize, millets, roots and tubers supplanted rice, sorghum and wheat in northern India? How would those kinds of changes play out in terms of shrinking agriculture’s land and water footprint?

The goal, says Davis, “was to determine what (if any) pattern of crops would minimize the green water (precipitation) and blue water (irrigation) demand of agriculture while also increasing production in terms of calories and proteins. Were there configurations that would leave rain-fed crops less susceptible to dry spells? Could crop distribution be optimized to reduce water consumption for irrigation and, essentially, leave more water in lakes and rivers?”

When they looked at their calculations, Davis and colleagues found that, indeed, reshaping the global distribution of crops within existing rain-fed and irrigated croplands could feed an additional 825 million people while reducing crop needs for rainfall and irrigation by 14 percent and 12 percent, respectively.

Crop change and redistribution also showed significant water savings for the economically important agricultural areas of southeast Australia, the Indo-Gangetic basin, California’s central valley, and the Nile Delta.

Figure: Spatial distribution of increases in calorie and protein production from crop redistribution. Maps in the left-hand column show the current distribution of calorie and protein production from major food crops on rainfed and irrigated areas. Maps in the right-hand column show the increase in nutrient production as a result of crop redistribution relative to current levels.

It’s important to note that the scientists constrained their distribution analysis to avoid creating monocultures. As the authors write, “crop replacement did not adversely affect the indicators of resilience that we consider because our replacement criteria explicitly required crop diversity to be maintained.”

 Benefiting Rural Communities and Developing Countries

“One of the important things about our study,” says Davis, “is that we also found that countries that adopt crop redistribution won’t necessarily need massive investments in modern technology often required by other efforts to sustainably intensify agricultural production. In many places that kind of investment would require switching from small-holder farms to large-scale agriculture, potentially displacing rural populations, or affecting their livelihoods, food security, and culture.”

Strategic crop redistribution, in contrast, puts a premium on using locally available technology as well as local knowledge to “sustainably intensify agriculture without increasing the environmental burden” – including use of water and fertilizers — of food production.

Of course, there’s no one silver bullet to solving the world’s agricultural challenges in a time of climate change, but Davis and his colleagues show the value of completely rethinking the way the world has always done things when it comes to food production.

“The next step for this work,” says Davis, “is to work with collaborators and policy-makers in populous developing countries – like India and Nigeria – to tailor this type of solution to local goals and needs. Our models look good, but there are obviously a lot of other considerations, which are different for each country, that go into developing policy solutions for more sustainable food systems.”

Cara Byington

Cara Byington is a science writer for The Nature Conservancy covering the work of Conservancy scientists and partners, including the NatureNet Fellows for Cool Green Science. A misplaced Floridian living in Maryland, she is especially fond of any story assignment involving boats and islands, and when not working, can be found hiking, kayaking or traveling with her family and friends. More from Cara

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