CNJ+ July 2025

NO SOILS, NO LIFE

They’re beneath our feet, but we seldom hear important signals in the soils “A nation that destroys its soils destroys itself.” President Franklin D. Roosevelt

We walk on soils, but often give little thought to what’s right under our feet. In fact, soils are the nation’s – and the world’s – breadbasket, providing food and a host of other necessities, including new medicines and materials. No soils, no life. Soils form over hundreds of years but can be destroyed by a single event, such as a hurricane. They’re vulnerable to wind and water erosion; pollut ants, including runoff from highways; and nutrient loss. Despite a humble exterior, soils are complex ecosystems composed of or ganic matter, minerals, water, air – and billions upon billions of organisms. These ecosystems orchestrate the processes essential for plant growth, as well as food and fiber production. The U.S. National Science Foundation is funding researchers who study soils and their importance in our lives. “As the planet’s population grows, scientists need a better understanding of the soil ecosystems that play a crit ical role in supporting societies around the world,” says Enriqueta Barrera, a program director in NSF’s Division of Earth Sciences. During Earth Science Week, with its theme “Earth materials in our lives,” NSF celebrates the soils beneath us. Ordering in for dinner? Plants long ago perfected the process. Next time you’re thinking about whether to cook dinner or order in, plants have been way ahead of you for eons. NSF-funded scientists at Rice and Cornell universities discovered that plants “call” for nutrients, using soil bacteria as a delivery service. Plants read the local environment and, when necessary, make and release mol ecules called flavonoids. These molecules attract microbes that infect the plants and form nitrogen nodules in the plants’ roots, generating food. When nitrogen is already available, plants don’t need to order in, says Rice biogeochemist Caroline Masiello. Their ability to sense the presence of a

The soil under a giant sequoia contains rich, diverse life. Photo Credit: Wikimedia Commons

nearby, slow-release nitrogen source – such as organic carbon – satisfies plants “hunger,” and stills their flavonoid signals. Understanding how soil carbon affects these signals offers scientists new ways of engineering beneficial interactions between plants and microbes and designing additives to balance deficiencies in soil. Leaf ‘tattoo’ monitors health of grapevines and ap ple trees Farmers and fruit growers have found that climate change is leading to increased ozone concentrations on the soil surface in their fields and or chards. That ozone can cause irreversible plant damage, reduce crop yields and threaten the food supply. Now, NSF-funded researchers led by Trisha Andrew at the University of Massachusetts Amherst have developed a way of placing “tattoos” on plant leaves. These polymer tattoos allow growers to detect and measure ozone damage, even at low levels. The tattoos also enable frequent and long-term monitoring of ozone damage to economically important crops such as grapes and apples. The scientists selected grapes (Vitis vinifera L.) as their model plant be cause the fruit yield and quality of grapevines decrease significantly when grapes are exposed to ground-level ozone, leading to economic losses. Ground-level ozone can be produced by the interaction between nitrates in fertilizer and the sun, for example, and is mitigated by early detection and soil treatments. The researchers hope their plant tattoo will be used nationwide by farmers and fruit growers, who could place a few “reporter plants” among crops to periodically monitor soil ozone levels.

Scientists have discovered that plants “call” for nutrients, using bacteria in soils as a delivery service. Photo Credit: Jeff Fitlow/Rice University

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JULY 2025