- Email: [email protected]
Soil Biology & Biochemistry Citation Classic XIV
Soil Biology & Biochemistry 105 (2017) A1eA2
Contents lists available at ScienceDirect
Soil Biology & Biochemistry journal homepage: www.elsevier.com/locate/soilbio
Citation Classic
Soil Biology & Biochemistry Citation Classic XIV Richard G. Burns Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4556, Australia
a r t i c l e i n f o Article history: Received 9 August 2016 Available online 31 August 2016
Soil organic matter (SOM) research has attracted and sometimes bemused many of the heavyweights of soil science for over one hundred years. It is impossible to visit the subject of SOM without stumbling across a lengthy who's who both past and present: Cameron, Gortner, Page, Starkey, Waksman, Jenny, Schollenberger, Norman, Jenkinson, Howard, the Russells, Oades, Hayes, Haynes, Greenland, Swift, Paul, Elliott, Baldock, Bremner, Martin, Brady, Degens, Franzluebbers, Six, Kuzyakov, Davidson, Lal, Nadelhoffer, Plante, Paustian, Stevensen, Theng, Emerson, Haider, Schnitzer, Balesdent, Chenu, Christensen, Skjemstad, Berg, Senesi, Zech, Cheshire, Sollins, Preston, Hatcher, Lehmann and Kleber. The list is € gel-Knabner, endless and our latest Citation Classic author, Ingrid Ko occupies a prominent place in the pantheon. All these big names have been intrigued by the complexities, dynamics and significance of SOM and worked hard to describe both the many factors that lead to its formation and to develop appropriate techniques to untangle the mysteries of its components and structure. What happens to dead and decaying plant, animal and microbial tissues and their numerous products when they enter soil? The disintegration, degradation and recycling of the hundreds of low and high molecular mass components has intrigued researchers and prompted no end of theories (and even more speculation). And what happens to organic inputs once they have been chemically and biochemically transformed? Some of the products go into the atmosphere, others provide energy and elements for microbial proliferation, much will supply nutrients for plant growth, some make a long term contribution to soil aggregation, water holding capacity, CEC and pH and others form highly recalcitrant complex structures that serve as an essential carbon sink. All of these properties and processes change in space and time and pose many more questions: what happens to organic matter in aggregates and associated with domains and clay surfaces; how are the different
E-mail address: [email protected]. http://dx.doi.org/10.1016/j.soilbio.2016.08.012 0038-0717/Crown Copyright © 2016 Published by Elsevier Ltd. All rights reserved.
components of plants, microbes and animals transformed; what are the contributions made by fungi, bacteria and archaea and do they function as individual genotypes or as communities; do decaying root materials differ from those arising from leaves and shoots; are subsoil transformations and fates significantly different from those in the surface soil horizons; how significant to these processes are intentional and unintentional charcoal additions; and to what extent, and over on what time scales, do climate change, afforestation and intensive agriculture influence all these processes and the relationships between pools, sinks and fluxes of carbon. Of course, many of these questions cannot be logically posed, let alone answered, unless we have reliable analytical techniques for measuring microbial composition and organic matter breakdown and fate in soil. Soil metagenomics is helping us make great strides towards identifying the players in organic matter transformation and the numerous modifications to the 82-year old Walkley and Black wet combustion technique (cited more than 5500 times!) and that grew out of their Rothamsted research, has been a faithful servant to our needs. But better and more precise and sensitive methods are needed to help us unravel the complexities and dynamics of soil organic matter. The author of this latest Citation Classic recollection, Ingrid €gel-Knabner, looks back at her landmark paper (Ko € gel-Knabner, Ko 2002) which has garnered 587 (Web of Science) citations. She recaps some of the influential ideas contained in her original paper, describes the key analytical and conceptual developments and concepts of the last 14 years as well as signposting directions for future research and the technological barriers that need to be overcome. Ingrid studied for her PhD at the University of Bayreuth under the astute guidance of Wolfgang Zech and remained there as a post doc for a few years. She then spent three years as Professor of Soil Science at Ruhr University in Bochum before moving to her present position as Chair in Soil Science in the School of Life Sciences at the Technical University of Munich in Freising-Weihenstephan. € gel-Knabner and her research group study the fundaIngrid Ko mental processes and properties controlling carbon and nitrogen cycling in soils and litter within natural and managed ecosystems, and the implications of these biogeochemical processes for land use change and land management. A primary goal of her work is to develop a stronger understanding of how soil parent material interacts with soil physical, chemical and biological
A2
R.G. Burns / Soil Biology & Biochemistry 105 (2017) A1eA2
properties to sequester or release carbon and nitrogen and these problems she tackles by studying organic chemical dynamics and soil structure from the submicron to the pedon scale. This research involves the application of analytical tools specifically designed to unravel the complexities of natural soil organic matter and she combines applications of long-standing molecular and isotope tools (chemolytic techniques, solid-state 13C NMR spectroscopy, 13C and 15 N stable isotopes) with novel methods (nano secondary ion mass spectrometry) in an attempt to untangle the association of organic and mineral materials in soils at the submicron scale. All this has resulted in over 250 publications of one sort or another, a stellar hindex of 55, and numerous awards for her research. € gel-Knabner's editorial services are in great deProfessor Ko mand and she is Joint-Editor-in-Chief of Geoderma, associate editor of the European Journal of Soil Science, Biology and Fertility of Soils and Organic Geochemistry, and a subject editor of Soil Biology & Biochemistry and Plant and Soil, as well as special editor for the Journal of Plant Nutrition and Soil Science. Ingrid is also a leading light in the successful series of five Soil Organic Matter Conferences. When Ingrid is not doing her cutting edge science she is passing on her experience to younger scientists organizing summer schools and coaching early career investigators in the skills of writing grant proposals. Ingrid lives in a small Bavarian village in the countryside and, when not being a scientist, enjoys cooking (and then consuming the results with a glass of red wine) and taking care of her garden -
but admits that the results are not convincing. Her two daughters are now grown up and she has rediscovered the delights of hiking tours with her husband. Upcoming (and strenuous) expeditions are planned in the Bavarian Alps and the Outer Hebrides. Soil biologists, in particular, have struggled with SOM because they know that understanding its origins, structure and properties is crucial to explaining how microbes function in soil. It is easy to turn a blind eye to these complex problems on the basis that they require expertise and understanding in chemistry, physics and biology as well as a thorough knowledge of the hundreds of papers published each month on these and related matters. So getting to grips with humic matter is a daunting prospect but the significance of organic matter formation and carbon sequestration and dynamics with regard to agriculture, climate, water quality and retention, soil stability, buffering, pollution mitigation, storage, ion exchange capacity, release of energy and nutrients and so on, cannot be denied and research to uncover and even control some of €gel-Knabner is in the these process is urgently needed. Professor Ko vanguard of this vital research.
Reference €gel-Knabner, I., 2002. The macromolecular organic composition of plant and Ko microbial residues as inputs to soil organic matter. Soil Biology & Biochemistry 34, 139e162.
Contents lists available at ScienceDirect
Soil Biology & Biochemistry journal homepage: www.elsevier.com/locate/soilbio
Citation Classic
Soil Biology & Biochemistry Citation Classic XIV Richard G. Burns Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4556, Australia
a r t i c l e i n f o Article history: Received 9 August 2016 Available online 31 August 2016
Soil organic matter (SOM) research has attracted and sometimes bemused many of the heavyweights of soil science for over one hundred years. It is impossible to visit the subject of SOM without stumbling across a lengthy who's who both past and present: Cameron, Gortner, Page, Starkey, Waksman, Jenny, Schollenberger, Norman, Jenkinson, Howard, the Russells, Oades, Hayes, Haynes, Greenland, Swift, Paul, Elliott, Baldock, Bremner, Martin, Brady, Degens, Franzluebbers, Six, Kuzyakov, Davidson, Lal, Nadelhoffer, Plante, Paustian, Stevensen, Theng, Emerson, Haider, Schnitzer, Balesdent, Chenu, Christensen, Skjemstad, Berg, Senesi, Zech, Cheshire, Sollins, Preston, Hatcher, Lehmann and Kleber. The list is € gel-Knabner, endless and our latest Citation Classic author, Ingrid Ko occupies a prominent place in the pantheon. All these big names have been intrigued by the complexities, dynamics and significance of SOM and worked hard to describe both the many factors that lead to its formation and to develop appropriate techniques to untangle the mysteries of its components and structure. What happens to dead and decaying plant, animal and microbial tissues and their numerous products when they enter soil? The disintegration, degradation and recycling of the hundreds of low and high molecular mass components has intrigued researchers and prompted no end of theories (and even more speculation). And what happens to organic inputs once they have been chemically and biochemically transformed? Some of the products go into the atmosphere, others provide energy and elements for microbial proliferation, much will supply nutrients for plant growth, some make a long term contribution to soil aggregation, water holding capacity, CEC and pH and others form highly recalcitrant complex structures that serve as an essential carbon sink. All of these properties and processes change in space and time and pose many more questions: what happens to organic matter in aggregates and associated with domains and clay surfaces; how are the different
E-mail address: [email protected]. http://dx.doi.org/10.1016/j.soilbio.2016.08.012 0038-0717/Crown Copyright © 2016 Published by Elsevier Ltd. All rights reserved.
components of plants, microbes and animals transformed; what are the contributions made by fungi, bacteria and archaea and do they function as individual genotypes or as communities; do decaying root materials differ from those arising from leaves and shoots; are subsoil transformations and fates significantly different from those in the surface soil horizons; how significant to these processes are intentional and unintentional charcoal additions; and to what extent, and over on what time scales, do climate change, afforestation and intensive agriculture influence all these processes and the relationships between pools, sinks and fluxes of carbon. Of course, many of these questions cannot be logically posed, let alone answered, unless we have reliable analytical techniques for measuring microbial composition and organic matter breakdown and fate in soil. Soil metagenomics is helping us make great strides towards identifying the players in organic matter transformation and the numerous modifications to the 82-year old Walkley and Black wet combustion technique (cited more than 5500 times!) and that grew out of their Rothamsted research, has been a faithful servant to our needs. But better and more precise and sensitive methods are needed to help us unravel the complexities and dynamics of soil organic matter. The author of this latest Citation Classic recollection, Ingrid €gel-Knabner, looks back at her landmark paper (Ko € gel-Knabner, Ko 2002) which has garnered 587 (Web of Science) citations. She recaps some of the influential ideas contained in her original paper, describes the key analytical and conceptual developments and concepts of the last 14 years as well as signposting directions for future research and the technological barriers that need to be overcome. Ingrid studied for her PhD at the University of Bayreuth under the astute guidance of Wolfgang Zech and remained there as a post doc for a few years. She then spent three years as Professor of Soil Science at Ruhr University in Bochum before moving to her present position as Chair in Soil Science in the School of Life Sciences at the Technical University of Munich in Freising-Weihenstephan. € gel-Knabner and her research group study the fundaIngrid Ko mental processes and properties controlling carbon and nitrogen cycling in soils and litter within natural and managed ecosystems, and the implications of these biogeochemical processes for land use change and land management. A primary goal of her work is to develop a stronger understanding of how soil parent material interacts with soil physical, chemical and biological
A2
R.G. Burns / Soil Biology & Biochemistry 105 (2017) A1eA2
properties to sequester or release carbon and nitrogen and these problems she tackles by studying organic chemical dynamics and soil structure from the submicron to the pedon scale. This research involves the application of analytical tools specifically designed to unravel the complexities of natural soil organic matter and she combines applications of long-standing molecular and isotope tools (chemolytic techniques, solid-state 13C NMR spectroscopy, 13C and 15 N stable isotopes) with novel methods (nano secondary ion mass spectrometry) in an attempt to untangle the association of organic and mineral materials in soils at the submicron scale. All this has resulted in over 250 publications of one sort or another, a stellar hindex of 55, and numerous awards for her research. € gel-Knabner's editorial services are in great deProfessor Ko mand and she is Joint-Editor-in-Chief of Geoderma, associate editor of the European Journal of Soil Science, Biology and Fertility of Soils and Organic Geochemistry, and a subject editor of Soil Biology & Biochemistry and Plant and Soil, as well as special editor for the Journal of Plant Nutrition and Soil Science. Ingrid is also a leading light in the successful series of five Soil Organic Matter Conferences. When Ingrid is not doing her cutting edge science she is passing on her experience to younger scientists organizing summer schools and coaching early career investigators in the skills of writing grant proposals. Ingrid lives in a small Bavarian village in the countryside and, when not being a scientist, enjoys cooking (and then consuming the results with a glass of red wine) and taking care of her garden -
but admits that the results are not convincing. Her two daughters are now grown up and she has rediscovered the delights of hiking tours with her husband. Upcoming (and strenuous) expeditions are planned in the Bavarian Alps and the Outer Hebrides. Soil biologists, in particular, have struggled with SOM because they know that understanding its origins, structure and properties is crucial to explaining how microbes function in soil. It is easy to turn a blind eye to these complex problems on the basis that they require expertise and understanding in chemistry, physics and biology as well as a thorough knowledge of the hundreds of papers published each month on these and related matters. So getting to grips with humic matter is a daunting prospect but the significance of organic matter formation and carbon sequestration and dynamics with regard to agriculture, climate, water quality and retention, soil stability, buffering, pollution mitigation, storage, ion exchange capacity, release of energy and nutrients and so on, cannot be denied and research to uncover and even control some of €gel-Knabner is in the these process is urgently needed. Professor Ko vanguard of this vital research.
Reference €gel-Knabner, I., 2002. The macromolecular organic composition of plant and Ko microbial residues as inputs to soil organic matter. Soil Biology & Biochemistry 34, 139e162.