Update: 21.03.2018

It can take more than 1000 years to form a centimeter of topsoil.

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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 - Gerard (Jerry) Hendrik Bolt (1925-2015)

Gerard (Jerry) Hendrik Bolt (1925-2015)

Gerard (Jerry) Hendrik Bolt, emeritus professor of Soil Chemistry and Soil Physics at Wageningen University, died in the 90th year of his life, on 12 January 2015 in Nieuwegein, the Netherlands.

Jerry was born on 8 April 1925 in Arnhem, the Netherlands, where he also attended primary and secondary schools.  In 1942 he graduated from the Lorentz Hogereburgerschool (H.B.S.-B), a type of secondary school strong in mathematics, physics, chemistry, biology and modern languages.  In a 2011 essay and the 2014 Hotel de Wereld Liberation Lecture, Jerry described in detail the eight tumultuous World War II and post-war years, which led him to soil chemistry and physics.  Soon after he started his studies at the Landbouwhogeschool (Agricultural University) in Wageningen, all Dutch universities came to a virtual standstill as a result of the demand that staff members and students sign a pledge of loyalty to the German occupying forces.  Jerry then switched to the Middelbare Koloniale Landbouwschool (Secondary Colonial Agricultural School) in Deventer.  Simultaneously, he also got involved in the soil survey of the Bommelerwaard in the Rhine-Meuse delta, carried out by a group led by Professor C.H. Edelman.  This contact initiated his interest in soil science.  After graduating from the Deventer school in 1945, he was qualified to start a career at some plantation in the Dutch East Indies.  But following the Proclamation of Indonesian Independence on 17 August 1945, he decided in early 1946 to return to the Landbouwhogeschool.

In Wageningen, contacts with his later colleagues Professors C.H. Edelman, W.R. van Wijk, and especially A.C. Schuffelen helped him to discover his real talents.  After obtaining the degree of Landbouwkundig Ingenieur (Ir.-equivalent to a MSc) in 1950, he emigrated to the USA and started graduate study at the Agronomy Department of Cornell University.  Just before he departed to the USA, Jerry married Irene de Klerk, who joined him at Cornell three months later, after she completed her Kandidaats (equivalent to BSc.) in chemistry at the Leiden University.

After Jerry’s intended supervisor M.B. Russell left to become Head of the Department of Agronomy at the University of Illinois, the younger soil physicist Bob Miller and the soil physical-chemist Michael Peech became Jerry’s supervisors.  Moreover, R.K. Schofield of Rothamsted Experimental Station temporarily replaced Russell.  Schofield’s experience and interest in the application of diffuse double layer theory in soil science stimulated Jerry’s choice of thesis projects for his MSc (1952) and PhD (1954).  As postdoc, Jerry continued his research at Cornell for another year.  Following that, for two years he was research chemist with DuPont Experimental Station at Wilmington, Delaware.

At the invitation of Professor Schuffelen to join him as Reader in Soil Science, Jerry returned to Wageningen Agricultural University in 1957.  His inaugural lecture was entitled ‘Adsorption equilibria in soil’ (in Dutch).  The Chair Groups of Professors Schuffelen and Edelman cooperated in setting up a new degree program in soil science.  Jerry’s general interest in reshaping university programs grew out of this and led to his intense involvement in debates and committees on this subject, both at Wageningen and nationally.  Over the years he tirelessly advocated modernizing the structure of Dutch universities by adopting certain aspects of the American model.  In his 1987 farewell lecture ‘Afstand nemen’ (literally ‘Taking distance’), he looked back in detail at the evolution at Wageningen Agricultural University over the last forty years, as a place to study, teach and do research.

Jerry modernized the teaching programs in general soil physics and physical chemistry.  In the period 1957-1961, I much enjoyed his teaching and advice.  In the advanced courses we were exposed to up-to-date treatments of swelling of pure clays, ion exchange processes, and the mechanisms of retention and flow of water in unsaturated soils.  His review papers ‘Thermodynamics of soil moisture (1960)’, with Martin Frissel, and ‘Cation-exchange equations used in soil science - A review (1967)’ brought welcome clarity for anyone interested in these rapidly developing subjects.

In 1963, Jerry was promoted to Professor.  In his inaugural lecture entitled ‘Differentiation and specialization in general soil science’ (in Dutch), he presented his views on the divergent needs of research versus practical soil scientists.  He stressed the need for research soil scientists to gain expertise in at least one basic subject, such as physics, chemistry, or mathematics.  As Professor, Jerry was qualified to supervise doctoral dissertations, although as Reader he had already supervised the PhD thesis research of Martin Frissel.  He supervised 15 PhD dissertations, of which 10 were based on research at the Agricultural University and 5 on results from agricultural research institutes.  The dissertations ranged from a few on physical subjects, more on physico-chemical subjects, and a few on chemical subjects.  For brief summaries of the dissertations, I refer to the article ‘About Professor G.H. Bolt’ by Frans de Haan and Hein ten Berge (Netherlands Journal of Agricultural Science 35: 212-218, 1987).

In the mid 1970s, it appears that Jerry felt that from then onward his talents were more needed in soil chemistry.  He left it largely to his staff to consolidate the course material on soil physics, which eventually in 1983 resulted in the textbook Elements of soil physics by P. Koorevaar, G. Menelik and C. Dirksen.

Jerry’s views on soil chemistry reached a quite definite form in the two volumes Soil Chemistry A. Basic elements (1978, 2nd ed.), edited with M.G.M. Bruggenwert and B. Physico-chemical models (1982, 2nd ed.), edited alone.  While all contributing authors are listed on the title pages, the editors made sure that the terminology, notation etc. were uniform. In fact the books could and probably still can serve as guidelines for a variety of courses, e.g. based on Jerry’s chapters on theoretical aspects of adsorption/exchange chromatography in soil science (64 pages) or on electrochemical phenomena in soil and clay systems (46 pages).  These two volumes reflect Jerry’s achievements in soil chemistry as a true scholar and a superb teacher.

Jerry was very active in the international arena: Fulbright Scholar at the University of California at Riverside in the USA (1964); Pye Fellow and visiting scientist with the Commonwealth Scientific and Industrial Research Organization (CSIRO) at Canberra in Australia (1970); visiting professor at Technion, Haifa in Israel (1979).

The arrangement with M.B. Russell for Jerry’s graduate studies at Cornell University came about at the 4th Congress of the International Society of Soil Science (ISSS) at Amsterdam in the summer of 1950.  Ever since this fortunate contact, Jerry remained very actively involved in ISSS.  He was President of Commission I (Soil Physics) in 1964-1968 and Commission II in 1986-1990, reflecting the shift of emphasis to predominantly soil chemistry.

Jerry Bolt was member of the ISSS Committee on Soil Physics Terminology that was formed at the 7th Congress at Madison WI, USA in 1960.  The Committee focused on basic terms related to statics and dynamics of soil water that are also of interest to other sciences such as plant physiology and micrometeorology.  The successive versions of the Committee report in ISSS Bulletin 20(1962), 22(1963) and 23(1964) reflect the hot debates among the committee members and commentators.  In 1973, the second Terminology Committee was appointed, of which Jerry became the Chairman and I was one of the six members.  The preliminary report was published in Bulletin 44 and discussed at the 10th ISSS Congress at Moscow in 1974. The final and final-final reports appeared in ISSS Bulletin 48(1975) and 49(1976).  The main differences with the report of the first Committee are the coverage of swelling/shrinkage phenomena and the greater detail in the definitions of the terms.  Jerry expertly handled the strong views of some Committee members and commentators, thus managing to keep the final report focused on the most important aspects.

Another major ISSS involvement stemmed from an ad-hoc ISSS Working Group that was set up at the 11th ISSS Congress in Edmonton, Canada in 1978 to focus on processes at surfaces of soil colloids. This resulted in a series of position papers ‘Proposals for coordinated research on the nature and properties of soil colloid surfaces’ published in ISSS Bulletin 60 (1981).  At the 12th ISSS Congress at New Delhi in 1982, the position papers were accepted and Jerry Bolt became the Chairman of the official ISSS Working Group.  This resulted in NATO-sponsored workshops at Ghent in 1984 and 1986, several small meetings, and eventually two books in the NATO ASI Series. Jerry served as first editor of the book Interactions at the soil colloid-soil solution interface (1991).  With one of his co-editors, Michael Hayes, and one of his successors at Wageningen, Willem van Riemsdijk, Jerry wrote three of the seventeen chapters. These chapters reflect Jerry’s keen interest in the history of soil physico-chemistry.  Of course differences of opinion remained. I recall the heated discussion with his contemporaries Phil Low and James Quirk during the 1991 NATO workshop on clay swelling and expansive soils at Cornell University.

At the 15th Congress in Acapulco, Mexico in 1994 Jerry made his last contribution at an ISSS Congress with a historical review on soil acidity.  The resulting paper ‘Soil pH, an early diagnostic tool: its determination and interpretation’ in Advances in GeoEcology (29: 177-210, 1997) reveals much of the often confused and divergent views within ISSS Commission II (Soil Chemistry) in the decades between World Wars I and II.

Jerry’s students, colleagues, and friends will always remember his precise formulations, his generously sharing ideas, his stimulating influence, and his great helpfulness.  Personally I have very good memories of his advice and help in 1961 when I chose for graduate study in the USA.  In the 1970-80s, the monthly meetings of the Working Group ‘Transport and accumulation phenomena in connection with soil contamination’, chaired by Jerry, provided a stimulating atmosphere for participants to share their latest findings and plans.

Not surprisingly, Jerry’s contributions to soil science and educational infrastructure were widely appreciated: he was knighted in the Order of the Dutch Lion; elected Fellow of the Soil Science Society of America (1968); elected Honorary Member of the ISSS (1998); awarded an Honorary Doctoral Degree by the University of Guelph in Canada (2000).

Jerry is survived by his wife Irene, their three children with partners, and four grandchildren.  Later this year he would have turned 90 and would have been married to Irene for 65 years.  Ten years ago they moved from Wageningen to Zeist, close to their children and grandchildren.  There they remained self-reliant as much as possible, enjoying their common love for classical music.  In recent years, Jerry’s interests kept widening, encompassing areas such as the functioning of our brain, and the latest theories in physics and astronomy. On Saturday 17 January 1915, his family paid tribute to him with moving speeches and live classical music, in the presence of friends, students, and colleagues.

Peter Raats