Update: 27.05.2018

Five tonnes of animal life can live in one hectare of soil.

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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.

in memoriam - Dan Hardy Yaalon (1924-2014)

Dan H. Yaalon was one of the most influential soil scientists in many decades, a long-standing faculty member of the Earth Science Institute of the Hebrew University of Jerusalem, a much decorated scientist with colleagues from many disciplines, and a devoted family man.
Dan passed away on Wednesday 29 January 2014. He was 89. Dan touched the ideas, the research, and students of many scientists. He traveled widely as a way to encourage soil science, to accelerate his own soils education, and to represent soil science to the world.
I never met Dan, but I corresponded with him electronically over many years, as did many. Recently, we co-wrote two papers, and throughout
the writing, he worried that he was not up on the literature and thus not a strong co-author. His contributions as co-author were classic Yaalon, intense, critical, and creative.
Dan’s soil scholarship is remarkable for both its fundamental nature and its breadth. He is one of only three winners of the V.V. Dokuchaev Prize given by the International Union of Soil Sciences. By the end of his career, he had made signature contributions to:

  • deserts and desert soils – for demonstrating how soils in xeric environments are formed by dynamic pedogenetic processes, and especially from wind deposited loess
  • paleo-pedology – for conceptualizing how past records of climates, biota, and geomorphologies are contained within paleosols, i.e., fossilized and buried soils
  • anthro-pedology – for articulating how naturally formed soils are becoming the parent material for human-formed soils
  • pedology – for how Earth’s soils are often poly-genetic, i.e., palimpsests with paleosolic features
  • soil science history, philosophy and sociology – for establishing a whole, new sub-discipline of soil science

While all five are important, two of these, polygenesis and anthropedology, are some of the most significant developments in the history of soil science
itself. In writing the remainder of this In Memoriam, I will not detail specifics of Yaalon’s research, they are widely accessible in the literature, but rather will I write about the making of Dan Yaalon the scientist. I use this opportunity to describe how his life offers much to young scientists as they consider a life’s work with the Earth’s soil.

Born in Czechoslovakia in 1924, Yaalon lost his mother in Auschwitz-Birkenau, a mother who had put him on a train at age 15 bound for Denmark, to save him from the Nazis. At the time his name was Hardy Berger and his dream was to travel through Denmark and Scandinavia on his way to Mandate Palestine. After arriving in Denmark, Hardy was assigned manual farm labor, but he took up his interrupted studies at an agricultural high school and later formally enrolled at the Agricultural University in Copenhagen. When the Nazis occupied Denmark, the Danish underground moved him and many other Jews to Sweden, where he found a job at the Agricultural University in Uppsala. Quite by accident, he was assigned to the research laboratory of Sante Mattson, a great soil chemist.
Yaalon later recalled, “Working with Mattson … at research tasks far beyond my acquired learning, I delved into advanced publications and books, working my way backwards from difficult expressions, formulas or citations, to the basics which explained what I was doing… This was a kind of backtracking detective work that branded my later activities in basic soil science.” The experience with Mattson was life altering as it firmly turned Yaalon to the science of Earth’s soil.

Late in the war and shortly thereafter, he travelled to Britain with the Czech Army and to Czechoslovakia where viewing post-war desolation he wrote with grave understatement, “visits to my hometown … were not very uplifting.” By July 1948, he had completed his undergraduate B.Sc. degree, worked as an assistant in a Danish research laboratory, and finally traveled by ship for Haifa to enter the new nation of Israel then two months old.

During a year in the Israel army, he visited agricultural settlements, mixed with scientists, joined geological expeditions into the Negev, and was accepted at the Hebrew University of Jerusalem for PhD studies. During these years he hebraized his name to ‘Dan Yaalon’, something that signaled an established life in Israel, and married Rita Singer. Together Rita and Dan shared nearly six decades and established a family that includes two sons and daughters-in-law, and seven grandchildren. As a PhD student in the early 1950s, the soil chemist Avraham Adolf Reifenberg became Yaalon’s advisor, and Yaalon was impressed by the small Department of Soil Science’s focus on arid zone soils, common worldwide but vastly understudied at that time with significant questions and needs that ranged from the local to global. In day-to-day terms however, Yaalon commented, “Doing research in those early days, with meager resources, involved overcoming many difficulties. Essentially self-taught we did our best to establish the research and teaching laboratories.”

These comments reveal perspectives strongly held by Yaalon about life and work. To Yaalon, “ingrained curiosity” was the basis for successful engagement with science. Yaalon’s university education, in Denmark, Sweden, and Israel, challenged him in ways that fed his native curiosity and gave him confidence
that Earth’s soil was well worth a life’s work. The making of a scientist according to Yaalon, included much that is fortuitous, unplanned, and even unfair, but what makes a successful scientist is “grabbing an opportunity when it arises.” Whether in science or in life, he said, “much is due to accidental events but what you make of it is very much subject to your choice and efforts.” Given the gravity of the “accidental events” in Yaalon’s life, these words underscore an incredibly positive message about science, life, and living.

Daniel deB. Richter, Duke University