XII. Personal Encounters with Outstanding Scientists

48



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specialized in SOM research. He traveled extensively, spoke eloquently, and was

an outstanding ambassador for SOM. I first met him at the 7th International Congress of Soil Science in Madison, Wisconsin, in 1960. During the evening of the

first day of meetings, we had a special session on nitrogen in SOM. Professor

Flaig argued that N was an integral part of SOM, chemically bonded to the major HA structures, while I contended that most of the N was physically adsorbed

or loosely held by the HA structural network. The debate lasted for several hours,

with many of the scientists who were present participating. It was one of the most

interesting debates in which I was ever engaged. Professor Flaig was a very skillful debator; he was conciliatory rather than confrontational. At the end of the debate we all had learned a lot and had become good friends. During the next few

days, I listened to his papers and also to his comments on other papers. As to the

synthesis of HAs, he postulated that lignin was oxidatively degraded to simple

phenolic monomers, which then polymerized oxidatively to produce HA. For this

reason, he considered HA to be highly aromatic. Essentially the same view was

also held by Professor Kononova. Thus, the two most prominent SOM specialists of that time agreed that HA consisted of aromatic (ring) structures and that

aliphatic structures were not significant. Professor Dr. Flaig also considered heterocyclic nitrogen to be a significant component of soil N. This has been confirmed by Py-FIMS (Schulten and Schnitzer, 1998). During the congress I met

Professor Dr. Flaig frequently and I found him to be a very sensitive, gentle and

civilized person, socially very adept, a good dancer, and who loved good food

and good wine. After the congress, we decided to exchange reprints and to stay

in touch. In 1967, he invited me to a very interesting meeting on SOM that he had

organized in Vienna on behalf of the International Atomic Energy Agency. In

1976, he organized a similar meeting in Braunschweig, sponsored jointly by the

International Atomic Energy Agency and FAO, to which he also invited me. During the 1970s and also in 1987, I visited him several times in Braunschweig and

in Wurzburg where we had many interesting discussions on the chemistry of

SOM. Professor Dr. Flaig was very active in international organizations, especially in the International Society of Soil Science. He was chairman of the Soil

Chemistry Commission for three successive terms. At the congress in Edmonton

in 1978, he worked very hard on my behalf and helped me to be elected Chairman of the Soil Chemistry Commission. My successor in this position was

Michael Hayes of the University of Birmingham, England, who was elected in

New Delhi in 1982. Thus, due to Professor Dr. Flaig’s status and hard work, SOM

chemists held the chairmanship of the Chemistry Commission of the ISSS for five

successive terms. After his retirement in the late 1970s, the research direction of

his institute changed and SOM was no longer the highest priority. All SOM

chemists felt that they had lost an outstanding spokesman when he retired. He is

now living in Garbrunn near Würzburg. I wish him many happy years of retirement.



A LIFETIME PERSPECTIVE



49



Professor D. H. R. (Sir Derek) Barton, FRS, Nobel Laureate

In 1961, the Director of the Soil Research Institute informed me that I was eligible for a sabbatical. I decided to spend a year in an organic chemistry laboratory in England, learning how to elucidate chemical structures of complex organic

molecules. After convincing my director that this was the right thing to do, my

wife, daughter, and I sailed to England from Montreal in September 1961. Several days after our arrival, I went to see Dr. D. H. R. Barton, Professor of Organic

Chemistry, at the Imperial College of Science and Technology in London, England, who had previously accepted me for a 1-year stay in his laboratory. Professor Barton was a tall, broad-shouldered, good looking man, with prominent glasses, in his midforties. He welcomed me to England and showed me his labs and also

my lab space. I was surprised by the large number of scientists who worked in these

labs. There were 50–60 scientists in the big lab and another 30–40 in several

smaller labs. Only 10 of those who worked there were Ph.D. students, the remaining 90 were either postdoctorate fellows or visiting scientists who came from

all over the world.

A few days later, I reported to work, equipped with a glass bottle containing 200

g of purified FA that I had extracted in Ottawa from a Spodosol Bh horizon. I had

decided to work on FA because I thought at that time that FA had a simpler molecular structure than HA so that FA would be more amenable to structural analysis than HA. After I started my work, I had a discussion with Professor Barton

about what I would do. He told me that because it was completely soluble in water and had a high oxygen-containing functional group content, FA was not a very

suitable material for organic chemistry. What I should do was to block the CO2H

and phenolic OH groups by methylation so that the FA would be soluble in organic

solvents such as benzene or chloroform and behave like an organic molecule. After testing a number of methylating procedures, I found the silver oxide-methyl iodide method most suitable for FA (Barton and Schnitzer, 1963). Three successive

methylations made 73% of the FA soluble in benzene. Chromatography of the benzene-soluble FA over Al2O3 gave on elution with benzene, ethylacetate, and

methanol seven fractions ranging in molecular weights from 260 to 918, in carbon

from 59.29 to 69.26%, in oxygen from 32.33 to 37.00%, and in OCH3 content from

25.79 to 47.86%. Several of the fractions were chromatographically homogeneous

but not molecularly. A straight line relationship was found between E 212 ␮m and

molecular weight. All fractions had very similar IR spectra and were devoid of optical activity. H NMR spectra of all fractions showed resonances at 9.10 and 8.75

␶, due to the presence of H in aliphatic CH3 and CH2 groups, and at 6.3 and 6.1 ␶,

due to OCH3 and CO2CH3, respectively. These were the first NMR spectra ever

recorded on a humic material (Wilson, 1987) and also the first unambiguous evidence that (CH2 )n, i.e., CH2 groups in long chains, were significant components

of humic substances.



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My work with Professor Barton clearly demonstrated that the chemistry of humic substances could be investigated by the methods of organic chemistry. During my stay at Imperial College, I had many discussions with Professor Barton on

different approaches to the chemistry of humic substances. I also had many opportunities to speak to a number of visiting scientists who were also working there

and who had many years of experience in structural organic chemistry. Professor

Barton also introduced me to many distinguished visitors who gave seminars there

and who were willing to discuss HA chemistry with me. My stay with Professor

Barton was a very rewarding experience both practically and intellectually. Imperial College was at that time a hotbed of organic chemistry, and I benefited greatly from that atmosphere. I am most grateful to Professor Barton for taking so much

interest in my research and for helping me in any way he could. At the end of the

1960s, Professor Barton won the Nobel Prize in Chemistry for his invention of

conformational analysis. He was knighted a few months later by the Queen of

England.

Professor M. M. Kononova

Professor Kononova became known internationally after the publication of her

book on SOM after World War II. This book was translated into many languages

and was required reading for many of us in the 1960s and 1970s. Professor

Kononova was Professor of Soil Biochemistry at the Dokuchaiev Institute of Soil

Science in Moscow and a member of the Academy of Sciences of the USSR. I followed her research since the mid-1950s and was impressed by her attempts to combine chemistry and microbiology in her studies on SOM. In 1974, I attended the

10th International Congress of Soil Science in Moscow, where I had the opportunity of meeting Professor Kononova in person. I remember her as a lively, kind

lady in her early seventies, always surrounded by a large group of co-workers and

assistants. She knew me through correspondence we had in the 1960s and through

my publications. Being one of the few SOM specialists in North America gave me

a special status in the eyes of Russian soil scientists who regarded SOM very highly. After the second session of the Soil Chemistry Commission she signaled to me

to sit beside her and asked me about my impressions of the congress and whether

I liked Moscow. She then proceeded to give me a small Russian doll as a souvenir.

This procedure was repeated after each session so that I ended up collecting a number of small presents, including some of her books. One morning, she invited me

to a reception at the Dokuchaiev Institute. As I entered her office, I was surprised

by the beautiful decorations on the walls and by the unusual abundance of delicious foods, cakes, fruits, and drinks on the table. Aside from Professor Kononova, her assistants, and the director of the Dokuchaiev Institute, a number of nonRussian scientists were present. These included Wolfgang Flaig, Jack Bremner,

and several scientists whose names escape me. We had a high-spirited discussion



A LIFETIME PERSPECTIVE



51



on SOM, while consuming a lot of food and drinks. All of us had a very good time.

Before leaving, we were given a tour of the institute and shown newly acquired

equipment, which included a sophisticated gas chromatograph and an amino acid

analyzer. It was obvious that Professor Kononova was well connected and that her

research was supported accordingly.

One afternoon, all attendants of the congress were scheduled to go on a sightseeing tour of Moscow. Apparently unaware of our schedule, Professor Kononova asked me to join her and co-workers for a discussion on the oxidative degradation of humic substances. My wife was accompanying me at that time because

she thought that we would join a sightseeing tour of Moscow, but she also was

invited to attend our discussion. After talking about our chosen topic for about

an hour, it was brought to Professor Kononova’s attention that my wife and I

had missed the sightseeing tour. She was very unhappy about this and assured

me that she would arrange a special tour for us. After 30 min, a large bus arrived

and the two of us plus an interpreter got on the bus. The driver plus the three of

us were the only passengers and we were given a wonderful tour of Moscow.

Thus, being a SOM specialist in Moscow at that time had certain advantages.

What impressed me most, however, were the power and influence of Professor

Kononova.

Professor D. S. Orlov

In 1957, after the launching of the Sputnik by the Russians, I began to take

courses in Russian at a local university. After 2 years of studying, I could read and

understand enough Russian to read abstracts of scientific papers and to get some

understanding of the contents of the papers. Over the ensuing years, I noted that

D. S. Orlov was one of the most prolific and imaginative Russian SOM researchers. After I contacted him by mail, we decided to exchange reprints. This

went on for a number of years, but I had no opportunity of meeting him in person

until 1974, when I attended the 10th International Congress of Soil Science. D. S.

Orlov at that time was Professor of Soil Biochemistry at Moscow State University. The second day after our arrival in Moscow, my wife and I proceeded to the

University to visit Professor Orlov. When we arrived at the soil science building,

I asked one of the concierges in Russian where Professor Orlov’s office was. He

answered me that he did not know. So I asked him very politely to look up Professor Orlov’s room number on his list. His answer was that the list was incomplete. After asking another concierge the same questions and receiving the same

answers, my wife and I decided to find Professor Orlov’s office on our own. We

walked along the lengthy gray corridors and noticed that none of the doors showed

name plates or numbers. All doors were identical, none of them exhibited any identification, so we kept on walking through colorless, endless corridors on the first,

second, third, and fourth floors. It was like a scene out of Kafka. We never met



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M. SCHNITZER



anybody who could divulge to us the secret of Professor Orlov’s office number.

After 2 hr of fruitless searching we returned to our hotel.

The next morning, as I was sitting in one of the lecture rooms, listening to the

first paper, a young lady tapped on my right shoulder and whispered into my right

ear: “Professor Orlov is waiting for you, please follow me quietly.” I got up and

followed her out of the lecture room, and then we proceeded to the building that

my wife and I had visited a day earlier. The young lady told me that she was Professor Orlov’s daughter and that she had graduated from the Philological Institute,

specializing in English. Again we walked along endless, gray corridors until we

entered Professor Orlov’s office. He was a man in his forties of medium height,

blond hair, and blue eyes. He was very happy to see me, and he immediately took

a bottle of vodka out of the cupboard so that we could celebrate our encounter appropriately. Apparently, somebody had told him that we were looking for him, but

he did not mention this to me. As we were familiar with each other’s work, he began by showing me his labs. I noticed that practically all of his equipment was

homemade. He and his students had built their own gas chromatograph and IR

spectrophotometer. It was amazing to me that Professor Orlov and students were

able to publish such excellent scientific work using so much primitive and outdated equipment. He demonstrated to me how well the equipment functioned. At that

time, my group and he and his co-workers were making wide use of thermal methods such as thermogravimetry and differential thermal analysis (DTA) in our research on humic substances. He showed me his home-built thermal equipment,

which functioned as well as ours, which we had purchased at high prices. During

our discussion, I noticed that Professor Orlov was a highly intelligent and very dynamic person who got very excited when he described his work. After the lab visit, he asked me to accompany him to the greenhouses where he was conducting

some experiments. Throughout my visit I never saw any “modern” equipment, although his work and contributions to SOM chemistry were outstanding. After 3 hr,

he suggested that I return to the meeting, guided by his daughter. I returned to my

seat in the lecture room during the presentation of the last paper and sat down quietly. Apparently nobody had noticed that I had been away for 3 hr.

I felt very depressed during the rest of the day. Here was a top scientist functioning in obscurity because of poor political connections. I never found out what

his political problems were, but they must have been serious because he was not

even allowed to attend the congress in his own city. I never saw Professor Orlov

again after our meeting. A few weeks after my return to Canada I received a parcel containing four books that he had authored. Three of the books were in Russian but one was in English. The latter was entitled “Humus Acids of Soils.” In

this book he discussed each of the reprints that I had sent him over the years. Some

of his comments were favorable, whereas others were somewhat critical. After

1975, our contacts ended. I never found out why. I began to realize how difficult

it was for an excellent scientist to survive in a totalitarian state, obviously was Pro-



A LIFETIME PERSPECTIVE



53



fessor Orlov’s problem. I hope that he is still alive and well and I wish him the

best.

Drs. J. M. Bremner and F. J. Stevenson

I met Jack Bremner and Frank Stevenson frequently at the annual meetings of

the Soil Science Society of America. The three of us also belonged to the NCR-59

Committee, which was set up by USDA for studies on SOM and whose members

met annually for 1- to 2-day meetings at universities in the midwest of the United

States. I attended these meetings regularly over a 20-year period. There were about

15–20 of us who belonged to this committee. At the meetings, each of us reported on what we had done during the past year and then discussed plans for the future. In this way we became aware of what each member was doing. Probably the

most important point of these meetings was that it provided us with a forum where

we could talk to each other. This was especially important for those who worked

in isolated locations. Jack Bremner was our “guru” at these meetings. He was not

only an eminent authority on soil N, but was also very knowledgeable on the chemistry of SOM. He had worked on SOM at Rothamsted prior to immigrating to the

United States and was an excellent chemist. We all told him about some of our difficulties, and he would suggest ways of how we could overcome our problems. He

was always upbeat and positive. I also met Jack at several International Soil Science Society meetings and we always had interesting times.

The careers of Frank Stevenson and my own ran along parallel lines. We started at almost the same time and are now in the twilights of our careers. The major

difference between us was that Frank started with studies on soil N, whereas I began my research with investigations on complexes formed among fulvic acid, leaf

leachates and leaf extracts, and di- and trivalent metal ions. After that, Frank did

extensive studies on metal complexation by HA and FA, while I began working on

the structure of HAs and FAs, and then turned to soil N. Frank also made excellent contributions to SOM chemistry through the books he authored. His book entitled “Humus Chemistry” is a very important source of information on SOM and

is widely consulted by students, teachers, and researchers. It brings together an

enormous amount of information on most aspects of SOM. I have referred to it often in this chapter. It was a great pleasure for me to share with Frank the Wolf Prize

for Agriculture in 1996.



ACKNOWLEDGMENTS

I am most grateful to the postdoctoral fellows, visiting scientists, and technicians who worked with

me for different lengths of time and who made outstanding contributions to my research. I also thank

a number of colleagues who collaborated with me on different aspects of my work. The following is a

list of all postdoctoral fellows and visiting scientists. The list shows their names and countries of domi-



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M. SCHNITZER



cile in chronological order: U. C. Gupta (Canada), E. H. Hansen (Denmark), G. Ogner (Norway), K.

Matsuda (Japan), R. Riffaldi (Italy), M. Ortiz de Serra (Argentina), G. B. Volk (USA), J. A. Neyroud

(Switzerland), S. M. Griffith (Trinidad), Y. Chen (Israel), N. Senesi (Italy), J. Cortez (France), K. Ghosh

(India), H. Kerndorff (Germany), M. Spiteller (Germany), G. Calderoni (Italy), G. Catroux (France),

M. Saharinen (Finland), E. Van Bochove (Canada), and L. Celi (Italy). I thank the following technicians: J. G. Desjardins, S. M. I. Skinner, E. Vendette, D. A. Hindle, B. S. Rauthan, P. R. Marshall, and

P. Schuppli. I am most grateful to the following colleagues: J. R. Wright, I. Hoffman, M. Lévesque,

P. A. Poapst, H. Kodama, F. J. Sowden, D. S. Gamble, S. U. Khan, K, Ivarson, S. P. Mathur, I. L. Stevenson, C. M. Preston, M. A. Arshad, J. A. Ripmeester, H.-R. Schulten, H. Dinel, C. A. Campbell, C. M.

Monreal, B. C. Liang, and T. Paré. I would like to single out Professor Dr. H.-R. Schulten for special

gratitude. He and I have collaborated very closely over the past 12 years on the development and applications of pyrolysis-mass spectrometric methods for analyses of SOM components in organic soil

extracts, HAs, FAs, humins, and whole soils and on the generation of HA, FA, and whole soil threedimensional model structures. Last but not least, I thank Agriculture and Agri-Food Canada for supporting my research over a long period of time and T. Paré for valuable assistance with proofreading

and typing of this manuscript.



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