Update: 18.09.2017

Soil carbon is the largest terrestrial pool of carbon.

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The International Union of Soil Sciences (IUSS) is the global union of soil scientists. The objectives of the IUSS are to promote all branches of soil science, and to support all soil scientists across the world in the pursuit of their activities. This website provides information for IUSS members and those interested in soil science.

Ruben Kretzschmar (Switzerland)

Ruben Kretzschmar (Switzerland)

Age: 45

Address: Institute of Biogeochemistry and Pollutant Dynamics
ETH Zurich
Universitatstrasse 16, CHN F29.2
CH-8092 Zurich, Switzerland

E-mail: kretzschmar@env.ethz.ch

Position:Professor of Soil Chemistry (since 1999)

1 When did you decide to study soil science?

I first discovered my fascination for soils during my undergraduate studies at the University Gottingen, Germany, where I studied agricultural sciences from 1983 to 1985. We had a truly excellent lecture in introductory soil science including several exciting field trips led by Prof. Brunk Meyer and his group. I was most fascinated about the variability of soil properties in the landscape and about how much information one can read from a soil profile, if one understands the processes leading to its formation. During my graduate studies at the University Hohenheim (1986-1989), I developed a special interest in soil chemistry and soil-plant interactions. I was also impressed and fascinated by the lectures of Prof. Ernst Schlichting on tropical soils and by many excellent field trips offered at Hohenheim, including a 2-week trip through southern Spain with Prof. Karl Stahr. After graduating in 1989, I decided to join the Ph.D. program of the Department of Soil Science at North Carolina State University, USA.

2 Who has been your most influential teacher?

There is no short answer to this question, because many different teachers and scientists have influenced my academic development in different stages of my career. My most influential teacher during my graduate studies was Prof. Horst Marschner, who was my Diploma thesis advisor at the University Hohenheim. During the time in his research group I experienced for the first time what it means to be a scientist. I studied the influence of Al-toxicity on growth of pearl millet and other crops in acidic sandy soils of Niger, West Africa. I conducted growth experiments in soil and solution culture, collected and analyzed soil solutions, measured root lengths, analyzed the nutrient status of the plants, etc., and ended up with a large data set to be interpreted. Horst Marschner was a great advisor during this time, because he always listened to my thoughts and gave inputs where needed. During the time at his institute, I learned a lot about rhizosphere processes, plant nutrition, soil-plant interactions, and about conducting research in general. As a PhD student at North Carolina State University, my most influential teachers were Profs. Wayne Robarge and Sterling Weed. Wayne Robarge taught me many important concepts in soil physical chemistry, while Sterling Weed was a great teacher in soil mineralogy. As a postdoc at ETH Zurich, I further developed my understanding of colloid and surface chemistry working with Profs. Hans Sticher and Michal Borkovec.

3. What do you find most exciting about soil science?

One of the most fascinating aspects about soil science is that it is a truly interdisciplinary science. One can study soils from the viewpoints of chemistry, mineralogy, physics, biology, social sciences, or other disciplines. It's a universe of its own. Also, many soils contain highly valuable information for archeologists, climatologists, and geoscientists. Another exiting aspect about soil science is its importance for nature and human life. Soils are one of the most important and vulnerable natural resources on earth. Practically the entire production of food and fiber depends on fertile soils. Protecting soils from degradation by human activities and global climate change will be one of the greatest challenges in the near future. Soil science can make a big contribution in this respect.

4. How would you stimulate teenagers and young graduates to study soil science?

Students interested in the functioning, management or use of ecosystems will be exposed to soil sciences at some point of their curriculum. At ETH Zurich, my course in Pedosphere is mandatory for BSc students in agronomy, forestry, environmental sciences, environmental engineering, earth sciences and biology. In this lecture course, I try to stimulate interest in soils by explaining the role and functioning of soils in supporting terrestrial life on earth. In the following year, we offer a series of soil science field excursions and practical exercises. Field courses are very important, because without them most students perceive soil science as something very abstract. It is important to experience soils in the field early on, because then also the theory behind soil functioning becomes more fascinating. That's at least how it worked for me.

5. How do you see the future of soil science?

At the global scale, food production for a growing population while preserving soil fertility and water resources remains one of the most pressing problems of this century. Soil scientists can make important contributions in this field, both at the fundamental and applied level. Soil science also has an important role in other environmental issues, e.g., protecting biodiversity, predicting global element cycles and the emission or absorption of trace gases relevant for global climate change, improving hydrologic and climatic models, or understanding and controlling the fate of organic and inorganic pollutants in the environment. In all these and other areas, fundamental and applied research on various aspects of soils is essential. There are many exiting opportunities, especially at the interfaces between soil science and other scientific disciplines. Therefore, I think that soil science does have a positive future. However, we need to convince policy makers that soil science should be given a high priority and that excellence in teaching and research in soil science needs to be maintained.