Can we have enough to eat and a healthy environment, too? Yes
-- if we're smart about it, suggests a study published in Nature this
week by a team of researchers from the University of Minnesota and McGill
University in Montreal. Global demand for food is expected to double by 2050
due to population growth and increased standards of living. To meet this
demand, it is often assumed we will need to expand the environmental burden of
agriculture. The paper, based on analysis of agricultural data gathered from
around the world, offers hope that with more strategic use of fertilizer and
water, we could not only dramatically boost global crop yield, but also reduce
the adverse environmental impact of agriculture.
"We have often seen these two goals as a trade-off: We
could either have more food, or a cleaner environment, not both," says
lead author Nathaniel Mueller, a researcher with the University of Minnesota's
Institute on the Environment and a doctoral student in the College of Food,
Agricultural and Natural Resource Sciences. "This study shows that doesn't
have to be the case."
Mueller and colleagues used management and yield data for 17
major crops to take a big-picture look at how much water and nutrients it would
take to bring under-performing farmlands to meet their food production
potential. They also looked for places where fertilizer use could be cut down
without substantially reducing crop yield. They found:
We could boost production 45 to 70 percent for most crops.
The greatest opportunities for yield improvement are found in Eastern Europe,
sub-Saharan Africa, East Asia, and South Asia.
Different inputs serve as limiting factors depending on the
region and crop. Nutrients, for example, appear to be limiting corn production
in Eastern Europe and West Africa and wheat production in Eastern Europe, while
nutrients and water appear to limit rice production in Southeast Asia.
Worldwide, we could decrease nitrogen use 28 percent and
phosphorus use 38 percent without adversely affecting yields for corn, wheat
and rice. China stands out as a hot spot of nutrient overuse, but other areas,
like the United States, Western Europe, and India, also have room to improve.
With strategic redistribution of nutrient inputs, we could
bring under-performing lands worldwide to 75 percent of their production
potential while only increasing global nitrogen use 9 percent and potassium use
34 percent -- and reducing phosphorus use 2 percent.
The researchers caution that their analysis is at a coarse
scale and that many other factors, including land characteristics, use of
organic fertilizers, economics, geopolitics, water availability and climate
change will influence actual gains in crop production and reductions in adverse
environmental impacts. Nevertheless, they are encouraged by the strong
indication that closing the "yield gap" on under-performing lands --
previously identified as one of five promising points for meeting future food
needs, along with halting farmland expansion in the tropics, using agricultural
inputs more strategically, shifting diets and reducing food waste -- holds
great promise for sustainably boosting food security.
"These results show that substantial gains are indeed
possible from closing the yield gap -- and combining these efforts with
improved management of existing lands can potentially reduce agriculture's
environmental impact," Mueller says. "They also offer concrete suggestions
as to where and how we can focus future efforts. This work should serve as a
source of great encouragement and motivation for those working to feed the
9-billion-plus people anticipated to live on this planet in 2050 while
protecting Earth's indispensible life support systems."
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