The ICTP College on Soil Physics celebrated its 20th anniversary this year. The activity has proved a valuable source of training for hundreds of scientists worldwide.

Soil Physics:
Twenty Years On

In 1980, while attending the ICTP Autumn Course on the Physics of Flow in the Oceans, Atmosphere and Deserts, Donald Gabriels casually sat down for lunch in the Centre's Main Building cafeteria. As he turned to his side, he was surprised to see the Centre's director, Abdus Salam, sitting next to him.
"Our conversation was what you would expect-seemingly nothing more than casual cafeteria chatter," Gabriels, a professor of agricultural engineering, University of Ghent, Belgium, recently recalled. "Salam asked me which activity I was participating in and what was my major field of research."
"Soil physics, I told him."
"You should prepare a course outline on the subject, Salam quickly replied, and send it to me. Perhaps we can organise a workshop here."
"Delighted by his invitation, several weeks after returning to my university, I sent Salam a detailed course outline and a brief description of the workshop's objectives. He responded in short order, saying the Centre had tentatively scheduled to hold a training activity on the subject. It was one of the most extraordinary turns of events in my career."
And, as Gabriels would subsequently learn, an unusual example of the sometimes positive power of miscommunication. You see, at their lunchtime encounter, Salam thought that Gabriels had said his major field of interest was solar--not soil--physics.
"Salam was expecting a course outline dealing with subjects close to the Centre's core fields of study in theoretical physics-perhaps an exploration of issues related to subatomical behaviour dealing with sunspots, solar magnetism and hydrogen bounding. What he received, instead, was a course outline with such headings as soil erosion, compaction and siltation."
"But rather than dismissing what I had given him, Salam was intrigued enough to let the proposal move forward. Only several years later, after our biennial colleges on soil physics had become a regular feature on the ICTP calendar, did Salam let me know that the activity was based on a mutual misunderstanding of what we had talked about at lunch."
The chance encounter--and misunderstanding--between Salam and Gabriels, which took place more than two decades ago, unwittingly laid the groundwork for one of ICTP's most unusual activities: the College on Soil Physics. Over time, some 500 scientists--80 percent of whom are from developing countries--have participated in the programme, which this March celebrated its 20th anniversary.
What is soil physics? In the simplest terms, it is the study of the physical characteristics of soil. Put another way, which emphasizes the dynamic processes that drive soil formation, use and evolution (and not just the medium itself in a static state), soil physics is the study of the physical laws of nature governing the behaviour of soil.
"While the definition of soil physics may appear simple," adds long-time College organiser Edward Skidmore, "the reality is that soil physics is a subject of infinite complexity. The study--and, equally important, the potential applications--of soil physics involve an understanding not only of physics but of biology, chemistry, hydrology, engineering and even land-use management." Skidmore, a research leader at the US Department of Agriculture, Agricultural Research Service, Manhattan, Kansas, has also served as one of the principal architects of the activity since its inception.

Edward Skidmore, Donald Gabriels, GianCarlo Ghirardi,
Ildefonso Pla Sentis and Donald Nielsen

The reason soil physics is so complicated lies in the fact that the health and behaviour of the soil depends on a complex interplay of factors: the physical and chemical composition of the soil; the diversity of flora and fauna living within the ecosystem in which a particular type of soil is present; the number and variety of soil microbes; the altitude and slope of the landmass; the rate and intensity of rainfall; and the density of human population and patterns of land development.
"Those who study soil physics," adds Donald Nielsen, a former dean at the University of California, Davis, USA, and the third 'founding' organiser of the event, "must process large amounts of data and information in order to build models that help us understand and, at times, anticipate soil behaviour under ever-evolving conditions--some of which are induced by nature, others by human activities.'' In developing such models, soil physicists must continually excavate a complex academic terrain that resides at the unspecified boundaries of mathematics, physics, chemistry, biology and agricultural science.
But, as Nielsen is quick to add, ''soil physics is not just an academic exercise. It carries important implications for understanding and responding to some of the most critical issues of our time: food security, access to safe drinking water, air and water pollution, and the prospects for such natural disasters as flooding and landslides." To shed light on these critical phenomena, soil physicists need to examine such complex environmental forces as erosion, water flow, runoff, soil transport, and carbon and oxygen diffusion.
The wide ranging critical issues that draw on information and insights provided by soil physics were on full display at this year's College, which took place from 3 to 21 March. Researchers came from a variety of fields that included not only physics but agricultural science, biology, chemistry, engineering, forestry and land-use management. Their places of work ranged from academic research centres to governmental agencies to universities to burgeoning private-sector consulting firms. Fifty-five out of 57 participants came from developing countries or countries with economies in transition.
The participants' scholarly research and on-the-ground work-related projects ranged from the construction of an irrigation system in the drought-prone Indian province of Guwahati; to the study of soil composition in Ghana, where food shortages remain a threat to public health and the physical well-being of the citizens; to the development of soil-related instruments in Brazil that help to measure the soil's water-retention capabilities, which is a critical parameter in determining the soil's potential health and long-term viability for food production.
The personal commitment and enthusiasm that participants at the College had for their work was clearly conveyed in how they chose to describe what they did.
"Don't call it dirt. It's not dirty. In fact, it's one of cleanest, most pristine materials that you would ever want to handle," says Daniel Okae-Anti, an agricultural scientist at the University of Cape Coast in Ghana, who was attending the College for the third time.
Okae-Anti's good natured but heartfelt description reflects his deeply rooted personal commitment to the study of soil genesis, which involves analysing the parent materials--the rock, sand, water, chemicals and microbes--that interact with one another under ever-changing climatic and weather conditions to create a particular category of soil. Okae-Anti notes that scientists have identified more than 200 orders or classes of soil worldwide and that each one of these orders may be divided into subcategories based on virtually endless local and regional ecological factors and processes.
Other participants at the College, including Gautam Barua, a professor of civil engineering at the Indian Institute of Technology, in Guwahati, India, and Carlos Vaz, an agricultural researcher at EMBRAPA's (Empresa Brasileira de Pesquisa Agropecuaria) Agricultural Instrumentation Institute, in São Paulo, Brazil, share Okae-Anti's sense of commitment to the study of soil. All agree that what they do represents more than a job to them.
"My work in India will help continue my country's efforts to increase the nation's food supply," says Barua. "We now recognise that increasing the level of food production in the short term cannot take place at the expense of the long-term health of the soil, which could suffer from rising levels of salinisation if our irrigation systems deplete groundwater levels faster than they can be replenished. The models that I helped to devise have enabled us to create engineering blueprints that serve both our short- and long-term needs for healthy and productive soil."
"The tensiometers that I designed," notes Vaz, "have allowed field workers to record valuable information on the level of water in the soil and the ability of the soil to retain water during periods of low rainfall. Such data is critical for determining the soil's potential productivity as well as its responsiveness to crop-rotation or irrigation strategies that might be implemented. In a sense, agriculture throughout much of the world has become an information-intensive industry and what I do helps increase the level of scientific data that both farmers and agricultural policy makers need to succeed."
"Just like beauty," Barua adds, "details are in the eyes of the beholder. And our ability to better understand the intricate nature of soil--in all of its elegant complexity--holds the key to addressing some of the world's most critical concerns."
"Some people may call it dirt, but on closer inspection, the soil is indeed one of nature's most elegant media and, more importantly, the basis of one of earth's most fundamental life-giving elements: our food supply."
For the past two decades, the ICTP College on Soil Physics has helped train hundreds of scientists to better apply their skills and talents to such a vital concern. This year--the 20th anniversary of the College--offered an opportunity for participants to extend their thanks to those who have made the activity possible, most notably directors Donald Gabriels, Edward Skidmore, Donald Nielsen and, more recently, Ildefonso Pla Sentis, coordinator of Escuela Latinoamericana de Fisica de Suelos (ELAFIS), as well as GianCarlo Ghirardi, professor of theoretical physics at the University of Trieste and long-time ICTP consultant, who has been the College's local organiser since the beginning.
If the enthusiasm displayed by the participants of this most recent College is any indication of things to come, the 20th year anniversary will likely be followed by many more Colleges in the years ahead.

Back to Contents Forward to Dateline

Home