A soil scientist and a farmer inspect a Daikon radish cover crop grown as part of a federally funded sustainable agriculture research project. This plant’s roots penetrate soil deeply, reducing compaction and increasing water infiltration. (SARE.org)
By Andrea Basche
If you have read The Grapes of Wrath, you’ll remember the catastrophic dust storms that arose in the United States during the droughts of the 1930s, causing farmers to abandon their land. These real events were driven by shortsighted farming practices that resulted in crop failures and bare soil that blew all the way to Washington, DC.
Today, similar shortsightedness— the practice of intentionally leaving fields bare much of the year—is once again making U.S. farmers and their surrounding communities vulnerable to extreme weather including droughts and flooding. Faced with increasing rainfall variability and the damage it can cause, farmers and policymakers should take steps now to protect soil and prevent the worst Dust Bowl–like consequences. In the new Union of Concerned Scientists (UCS) report, “Turning Soils into Sponges,” we examine how smart farming practices can build rich, porous, sponge-like soils to help minimize the effects of both floods and droughts. Healthy, spongy soil holds more water, allowing it to reduce runoff during rainstorms and to hold water longer during dry periods.
Healthy, spongy soil holds more water,
allowing it to reduce runoff during rainstorms
and to hold water longer during dry periods.
By analyzing 150 field experiments from around the world, we found that keeping living roots in the soil year-round is a highly effective way for farmers to create valuable sponge-like soil. Farmers can achieve this by planting perennial crops and cover crops, as well as through improved livestock grazing practices. We also used a hydrology model to predict how much difference these practices could make if adopted on a large scale. Focusing on the state of Iowa as a representative example of Midwestern agriculture, we showed that planting perennial or cover crops on the most-erodible croplands in the state would reduce rainfall runoff up to 20% in flood conditions, and make as much as 16% more water available to crops during droughts.
Unfortunately, while many farmers are interested in building healthier, spongier soil, they face barriers in policies that make it riskier and less profitable for them to try. Congress and the U.S. Department of Agriculture can make it easier for farmers to adopt these beneficial practices through greater investments in research and technical support and changes to the federal crop insurance program.
Even as climate change presents new challenges for farmers, soil can be an important part of the solution to minimizing flood and drought impacts—and creating a more sustainable U.S. agricultural system. Find our report, along with a fun video demonstrating how healthy soils can mitigate the effects of droughts and floods, at www.ucsusa.org/SoilsintoSponges.
Andrea Basche, a specialist in sustainable agriculture, is a former UCS Kendall Science Fellow.
Reprinted with permission from the Union of Concerned Scientist’s newsletter Catalyst, Volume 17, Fall 2018. Learn more at www.ucsusa.org.
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