Critical Zone Exploration Network

Some of society’s most important scientific questions have little to do with space travel, human disease, theoretical physics, or new math. Some of the most important scientific questions today are about the future of Earth’s soil.

To promote and expand the world’s long-term soil-research base, a workshop was convened in December 2007 at Duke University and the Center for Environmental Farming Systems in North Carolina USA. The workshop formally established a global network of long-term soil-research studies, several of which have been in continuous operation since the 19th century. Workshop participants study soil and ecosystem change in Africa, Asia, Australia, Europe, and the Americas.

The workshop featured the proposition that soil studies spanning decades are key to answering some of the most significant questions faced by humanity today:
• Can soils more than double food production in the next few decades?
• How is soil interacting with the global carbon cycle and climate?
• How can land management minimize its adverse effects on the environment, and improve soil’s processing of carbon, nutrients, wastes, toxics, and water?

Comprehensive research from long-term experiments provide direct observations of soil processes and change that are evident only after years and decades. The data from these decadal experiments are invaluable for improving the quality of human life and that of the environment.

An advanced-format website supports the newly established network of long-term soils research and connects more than 150 long-term studies with researchers, teachers, and students from around the world. The advanced website originated in a graduate class at Duke University and it encourages scientists to work together more closely and in ways unknown even in the recent past (http://ltse.env.duke.edu). Workshop participants are enthusiastic about the future of cross-site research that this new networking promises.

At the workshop, new results were presented from long-term studies of soil fertility, chemical contamination, crop production increases and declines, greenhouse gas emissions, and water quality, all demonstrating and quantifying soils’ susceptibility to change.

Dr. David Powlson of Rothamsted Research, England and a pioneer in research that uses data from multiple long-term soil experiments, challenged participants that there is great short-term potential for cross-site studies to advance the science of sustainability. Dr. Henry Janzen of the long-running Lethbridge field studies in southern Alberta, Canada, vigorously argued that new long-term studies are needed to meet the growing economic and environmental demands being placed on soils now and in the next few decades.

Participants are particularly concerned about crop declines observed in several long-term experiments. Research on intensively managed rice (an agro-ecosystem that currently feeds more than two billion persons) indicates yield declines in several locations, declines attributed to a variety of causes, some of which involve unexpected changes in the soil. More recent studies suggest that adverse climatic changes such as an increase in night temperature could be responsible for declining rice and wheat yields.

Participants also have grave concerns about the poor funding support for long-term soil studies. Not a few long-term studies operate without stable institutional support and remain productive only by the persistence of individual scientists. Several highly productive long-term experiments have even been abandoned in recent years, including important studies in Africa and South America.

Coincident with the Duke workshop on long-term soil studies, Nature magazine of 6 December featured papers that emphasized the importance of long-running measurements of the Earth’s environment. In a quote repeated several times during the soils workshop, the Nature editorial proclaimed, “Data sets encapsulating the behavior of the Earth system are one of the greatest technological achievements of our age – and one of the most deserving of future investment.”

According to workshop organizer, Dr. Daniel Richter, a professor of soils and ecology at Duke, “Long-term records are key to predicting the weather, air pollution, river floods, and wildlife populations. Similarly, long-term soil observatories need explicit and much greater support not only to improve our rapidly intensifying management of land and water, but also to better manage environmental change.”

The workshop concluded that in the short-term, researchers and students should make the most of results from on-going long-term experiments. In the words of Dr. Ishaku Amapu, a professor of soil fertility from northern Nigeria who studies a continuous cropping experiment that began in 1950, “We need to make our long-term experiments work harder.”

Such long-term research requires long-range planning and workshop organizers invite interested scientists, students, and the public to join this international effort. Organizers have funding support from USA’s National Science Foundation’s Research Coordination Network Program and Critical Zone Exploratory Network, the United States Department of Agriculture, and Duke University for five yearly meetings.