Members of the local environmental group Greening Greenfield (GG) say that “soil sponge” is a vital concept that offers hope in the face of climate crises. The group launches its 2026 speakers series, “Water and Our Climate,” this Monday, Jan. 26 at 6:30 p.m. via ZOOM, featuring the renowned author Didi Pershouse, who’ll speak about “Regenerating the Pioneer Valley’s Soil Sponge and Living Climate.” Visit Greening Greenfield website for link.
The prevalence of roadways and other hard surfaces results in rainwater run-off and cities heating up.
“Many people recognize the importance of green, open spaces,” said GG member Dorothea Sotiros. “Yet a lawn can be almost as bad as concrete if the soil is easily compacted and the frequently mowed grass never has the chance to grow deep roots.”
Fellow GG member Nancy Hazard added, “Water running off of lawns contributes to flooding and often carries fertilizers and herbicides to our streams.” Both women emphasized the importance of planting a wide variety of native plants, including some with deep roots.
“Every continent is drying,” said Hazard. “Revegetating our planet and restoring the soil sponge will help reduce the yo-yo effect of floods and droughts. We need to look at the big picture, and that’s where Didi Pershouse’s expertise can give us a boost.”
Pershouse is the founder of the Land & Leadership Initiative, which aims to equip communities to meet the challenges of climate and soils at local levels. Her curriculum, “Understanding Soil Health and Watershed Function,” is used in more than 100 countries; her work has inspired a million natural farmers in India alone.
I spoke with Pershouse in advance of her talk. “The key thing is to get water to soak into the land,” she said, adding that plants are a major part of that process. But not just any plants: people can help by planting vegetation of many different types.
Apparently what some people perceive as a beautiful lawn isn’t just modern or trendy. Evolutionarily, lawns mimic the savannah, “where humans felt most safe,” Pershouse explained. “A wide expanse dotted with trees you can hide behind,” she said.
However, many lawns don’t allow rainwater to soak in. Pershouse noted that lawns with varying plant heights work better. “We need plants with deep roots and shallow roots, plants that love heat and some that love cooler (temperatures),” she said. Such variety allows plants to “do their work and feed the underground workforce.”
Sotiros noted that the underground work force consists of microorganisms that do the work of cycling water and carbon while filtering water and creating storage structures that provide drought resilience. Our regional landscape has experienced many water-related challenges in recent years.
“Farms flood, while wells run dry and droughts are declared,” Sotiros said. “Rebuilding our soil’s ability to infiltrate and store water can help prevent these problems.”
Hazard credits Sotiros with the inspiration to focus on water-related issues. “Dorothea drew my attention to Didi’s work and that of Australian soil scientist Walter Jehne, which helped me understand the vital role the water cycle plays in regulating the climate, as well as how vegetation fuels the water cycle, and how the loss of vegetation has contributed to a warming climate,” she said.
Pershouse pointed out that, several decades ago, when people started discussing climate topics in earnest, much of the focus was on fossil fuels.
“That’s certainly part of the problem, but there are many other things we can and need to do,” she said. “For one thing, the deforestation rate is alarming.”
She noted that, ironically, certain types of northeastern U.S. trees yield wood that burns at just the right temperature to melt metals used to create solar panels, which are popular in Europe.
“There are big financial interests,” she said.
Yet, deforestation increases run-off, which leads to both more floods and more droughts. It’s a cycle humans have the power to halt.
The good news is that there are government employees and large-scale farmers who’ve changed their thinking and practices. “That’s what I love about this work,” said Pershouse. “It involves people from different backgrounds, including conservative midwestern farmers who’ve taken positive steps toward soil health.”
And not just big farms come into play: “In terms of soil sponge, if everyone who has a balcony had plants on it, that building would be cooler. Everyone can do something.” Yet of course, it’s also vital to look at the timber industry, big agriculture and cities that are already built.
“We need more trees, and to plant them in better tree wells,” said Pershouse. “We need rivers not to be paved over. In some places, sponge cities are being created: in China, Africa, India … places we don’t hear much about.”
And as ever, big economic interests are pushing back.
In explaining why plants are a key factor, Pershouse describes a process called transpiration, in which plants release water vapor into the atmosphere. “Plants must have water at the root zone,” she said. “They can’t do the job of cooling air and feeding all of life if there’s no water storage. Plants that can’t grow and transpire can’t address climate regulation. They’re unable to affect heat, flooding, and drought if the water doesn’t soak into the land.”
Hazard said the biggest thing she wants people to understand is that humans can have a positive impact: “We can support a healthy, functioning water cycle by planting more vegetation which will create more clouds, rain, and healthy, spongy soil, which in turn will cool our planet. Members of Greening Greenfield really want everyone to understand this!”
Eveline MacDougall is the author of “Fiery Hope” and can be contacted at eveline@amandlachorus.org.