World Soil Day Celebrates Earth’s Life-Supporting Resource

By Dorothy Merritts, Professor, Department of Earth and Environment, Franklin and Marshall College

In 2014, while attending a National Science Foundation (NSF) workshop on infrastructure for Earth surface processes research at the Field Museum in Chicago, my colleague, Laurel Larsen, and I toured the museum’s “Underground Adventure” exhibit. The exhibit encouraged us to imagine shrinking to a size smaller than a penny to examine soil from a new perspective, and we did so with zest. Our underground adventure reminded me of famed soil scientist Hans Jenny’s joy when working with soil or experiencing it aesthetically through landscape paintings:

“Soil appeals to my senses. I like to dig in it and work it with my hands… I like to sit on bare, sun-drenched ground and take in the fragrance of soil… In loess country, plowed fields on slopes show wide bands of attractive color gradations from dark browns to light yellows, caused by erosion of the surface soil. Warm brownish colors characterize fields and roofs in Cezanne’s landscape paintings of southern France, and radiant red soils of the tropics dominate canvasses of Gauguin and Portinari.”

Jenny’s fascinating musings on landscape art and soil were published in a Pontifical Academy of Sciences proceedings volume for a 1968 conference, “Organic Matter and Soil Fertility,” held in Vatican City. The conference focused on the vital role of soils to human well-being, consistent with the Vatican’s assertion that science must “tend towards the good of all mankind.” Nearly half a century later, signs in the “Underground Adventure” exhibit stated, “It’s not just dirt—it’s the key to life!” And yet, somehow, soil has been taken for granted, degraded, eroded, blown away, washed away, trapped in countless reservoirs behind dams, polluted, and more.

About a year after attending the NSF workshop, Dr. Larsen and I—along with other workshop participants—published an opinion piece in Eos, recommending a campaign to capture the pulse of the planet: the past, present, and future status of Earth’s surface systems. We noted that quantifying environmental parameters, such as the movement of water, sediment, and solutes, is key to understanding Earth dynamics. However, scientists need a common set of baseline measurements across a wide range of climates and geology.

Hans Jenny had much the same idea in mind soon after he moved from Switzerland and had the opportunity to tour America. Jenny noted that while traversing North American landscapes by train from east to west, passing through enormous ranges of climate and becoming particularly enthralled by the rolling plains of the Midwest, he could hardly sleep from the exciting revelation that soil types could be related to climate by mathematical functions. Within months, he was analyzing newly available soil databases from different states to identify trends between temperature and soil nutrients.

Like Hans Jenny, in different times and ways, modern scientists strive to assemble data and build models at a range of scales in order to understand and “take the pulse of Earth’s surface system.” About 3,000 abstracts representing 10 different AGU sections at this year’s Fall Meeting will report on some attribute of soil. Many scientists will expand their research to incorporate not just soil, but the whole “Critical Zone,” which is described as “a living, breathing, constantly evolving boundary layer where rock, soil, water, air, and living organisms interact.”

Whether we are inspired by the beauty of soil, or by the key role it plays in Earth systems and the Critical Zone, we all should advocate for the preservation and rehabilitation of this life-supporting resource. World Soil Day, held every 5 December since it was established in 2013 by the Food and Agriculture Organization of the United Nations, is an international effort to raise awareness of the importance of soils. This World Soil Day, I urge AGU scientists to help draw attention to the value of soil for our planet, just as Hans Jenny did throughout his entire career.