Methane emission from rice fields

Methane (CH4) and carbon dioxide (CO2) are the end products of carbon decomposition in rice fields and other wetlands. Methane, a major greenhouse gas, is the terminal step of the anaerobic breakdown of organic matter in wetland soils. It is exclusively produced by methanogenic bacteria that can metabolize only in the absence of free oxygen and at redox potentials below -150 mV (Neue et al. 1997).

According to the above-cited paper by Dr.H.U. Neue (former Head of the Soils Department at IRRI and later Professor of Soil Chemistry at the University of Halle-Wittenberg, Germany) one of the pioneers in methane research in rice fields, methane is largely produced by transmethylation of acetic acid and to some extent, by the reduction of carbon dioxide in wetland soils.

The rate and pattern of organic matter addition and decomposition also contribute to the rate and pattern of methane production. In rice field, methane production generally increases during the cropping season. Easily degradable soil carbon, plant litter, root exudates, decomposing roots and aquatic biomass that are added to the anaerobic zone of the paddy soil (this is the zone below the thin oxidized or brown soil surface) are the major carbon sources for methane production.

Presently, there is widespread research interest in the development of methods and strategies to reduce methane emission from rice fields and other wetlands. Some early studies have shown that sodium chloride at high concentration inhibits methane formation. Addition of sea water has also been found to inhibit methane formation at low salt concentration because of its sulfate content. Very recently, Dr. Roel R. Suralta and colleagues at Philrice, Nueva Ecija, have demonstrated that iron fertilizer application significantly reduced methane emission from rice field. More importantly, the iron fertilizer application also increased rice yield (Suralta et al., 2011).

References

Neue HU, JL Gaunt, ZP Wang, P Becker-Heidmann, and C Quijano. 1997. Carbon in tropical wetlands. Geoderma 79: 163-185.

Suralta RR, FS Gorospe, CA Asis Jr and K Inubushi. 2011. Effect of iron fertilizer application on the yield and methane emission of paddy rice field. In: Proceedings of the 14th Annual Meeting and Scientific Conference, Philippine Society of Soil Science and Technology (PSSST), VSU, Baybay, Leyte 25-27 May 2011, pp:95-96

Report on the 14th PSSST Scientific Conference held at VSU, Baybay, Leyte

The 14th Annual Meeting and Scientific Conference of the Philippine Society of Soil Science and Technology (PSSST) was held at the Visayas State University (VSU) in Baybay City, Leyte last 25-27 May 2011. About 140 soil scientists, soil practitioners, and agriculturists working in universities, government agencies, non-government organizations, and private companies throughout the country attended the conference.

The opening program was graced by Dr. Florentino Tesoro who represented Congressman Angelo B. Palmones (AGHAM Partylist), Dr. Jose L. Bacusmo (VSU President), Prof. K. Stahr (Germany), Mr. Deogracias Pernites (representing Mayor Carmen Cari of Baybay City), Dr. Cezar Mamaril (PSSST Adviser), Dr. Eduardo Paningbatan (PSSST Adviser), Ms. Constancia Mangao (PSSST President) and Dr. Victor B. Asio (Dean of the College of Agriculture, VSU).

Prof. Dr. Karl Stahr, the Chairman of Division I of the International Union of Soil Sciences (IUSS), gave the keynote lecture about the limestone soils in Southeast Asia particularly Thailand, Vietnam, and Laos. Dr. Gamini Keerthisinghe of the Australian Centre for International Agricultural Research (ACIAR) gave a plenary paper on challenges to sustainable crop production.

A total of 26 oral papers were presented dealing with various soil topics ranging from fertilization to soil characterization and geospatial modeling. In addition, 25 poster papers were presented. The presenters of the best oral and poster papers were awarded with certificates and cash.

In the afternoon of the last day of the conference, a post-conference tour was organized and sponsored by the Department of Agronomy and Soil Science of VSU to Lake Danao located at 630 m ASL in the central highlands of Leyte. On the way to the lake, the participants were able to see the following: 1) the City of Ormoc; 2) the mouth and headwater of Anilao River which caused the tragic flooding of Ormoc City in 1991 killing 8,000 people; 3) the volcanic landscape which was traditionally used for large-scale sugarcane production; 4) the 1,912 ha Lake Danao along the Philippine Fault Line; 5) an Andisol soil profile (Typic Hapludand); and 6) the Tongonan Geothermal Plant, one of the largest in Asia.

Overall, the conference was a great success. The attendance of Prof. Stahr from the University of Hohenheim in Germany and Dr. Keerthisinghe from ACIAR in Australia gave the conference an international standing especially since Prof. Stahr represented the IUSS of which PSSST is a member.

The Department of Agronomy and Soil Science of VSU which co-hosted the conference, is grateful to the VSU president for the encouragement and support, and the officers and advisers particularly Dr. Cezar Mamaril of PSSST for bringing the conference to VSU.

A report on this conference has been published in the IUSS Bulletin Vol. 119 (Dec 2011 issue)

(All photos were taken by Glenn Largo)

Soil Science is also called pedology

In American soil science, pedology (pedo is Greek for ground or soil) has recently been made as a subdiscipline that deals with soil morphology, genesis and classification. In other parts of the world, however, particularly in non-English speaking countries in Europe, Asia, and Africa soil science has remained synonymous with pedology (Bech, 2006). Historically, pedology was the original term for the scientific study of the soil introduced by Fallou and it was only in 1924 during the planning for the first international congress that the term soil science was introduced as a synonym. This was in fact reflected in the paper that Glinka presented during the congress (Glinka, 1927).

Until today many textbooks, scientific journals, and academic departments dealing with soil science in non-English speaking countries bear the name pedology. In 2002, there was an internet debate among some members of the International Union of Soil Sciences (IUSS) about the term pedology. While many North Americans who joined the debate strongly argued for the use of pedology as a branch of soil science, most soil scientists from Europe (e.g. the world-renown R. Dudal from Belgium) and other parts of the world maintained that pedology is synonymous to soil science and is not a subdiscipline. Because of the disagreement, pedology was not used as a subdiscipline in the IUSS,

The traditional branches of soil science include soil chemistry, soil biology and biochemistry, soil physics, soil mineralogy, soil genesis, survey and classification, soil conservation, and soil fertility. Many soil scientists at present are experts of new emerging fields of soil science like hydropedology (interaction between hydrosphere and pedosphere), landscape pedology (role of soil in landscape processes), ecopedology (role of soil in terrestrial ecosystems), soil biogeochemistry (how biological and geochemical processes in soils affect element cycle), pedometrics (use of mathematical and statistical tools to interpret and analyze soil data), soil geography (local, regional and global distribution of soils), soil protection, and soil science history.

References
Bech, J. 2006. Eupedology: a solution to a controversy. IUSS Bulletin 109: 27-30.
Glinka, K.D. 1927. Dokuchaiev’s ideas in the development of pedology and cognate sciences. Trans. First Intern Congr. Soil Sci., Wisconsin, vol. 1, pp: 116-135

Leading Soil Scientist is Keynote Speaker of the 14th PSSST Conference in May 2011

Prof. Dr. KARL STAHR, Chairman of Division I (Soil in Space and Time) of the International Union of Soil Sciences (IUSS), the global association of soil scientists, has accepted our invitation to be the Keynote Speaker of the 14th PSSST Scientific Conference on 25-27 May 2011 at VSU, Baybay, Leyte, Philippines.

Prof. Stahr gained his doctorate from the Technical University Stuttgart, Germany, in 1972 and his Habilitation (highest academic qualification required to become a professor in Germany and several other European countries) in Soil Science at the University of Freiburg in 1979. Since 1988 he is Professor of Soil Science and Petrography at the Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart. His main fields of research are: soil genesis, soil mineralogy, land evaluation, N-cycle, and recycling of organic waste. He has conducted research projects dealing with forest and agricultural soils of Germany as well as Brazil, Ecuador, Argentina, Spain, Portugal, Egypt, Israel, Turkey, PR China, Somalia, Niger, Benin, Vietnam, Thailand, and Philippines.

Prof. Stahr has been actively involved in a wide range of professional activities serving as: Vice Chairman (1979-1981, 1985-1989) and Chairman (1989-1995) of Commission VII of the German Soil Science Society, Vice Chairman of Commission VII of the International Soil Science Society (1986-1998), and President of the German Soil Science Society from 1998 to 2001. He has organized several national and international workshops, excursions and congresses.He has been elected member of many University boards since 1967 such as Dean of the Faculty of Landscape Planning, Technical University of Berlin (1987/88), Dean of the Faculty of Plant Production and Landscape Ecology, University of Hohenheim (2000-2002) and as Vice Dean of the same faculty since 2002. He also serves as Chairman of the special research project "Uplands Program 564" of the University of Hohenheim since 2005.

He has authored and co-authored hundreds of papers which appeared in prestigious peer-reviewed international journals as well as several influential textbooks in soil science (in German). He is in the Editorial Boards of Catena, Plant Nutrition and Soil Science, Geoderma, Trends in Soil Science, and Hohenheimer Bodenkundliche Hefte.

Prof. Stahr has supervised close to a hundred PhD students from many countries around the world.

National Conference of the Philippine Society of Soil Science to be held in May 2011

The Philippine Society of Soil Science and Technology Inc (PSSST) will hold its 14th Annual Meeting and Scientific Conference on 25-27 May 2011 at the beautiful campus of the Visayas State University (VSU) in Baybay, Leyte, Philippines.

Theme of this year's conference is Improving the Productivity of Marginal Lands Through Integrated Soil and Water Management. Marginal lands particularly degraded uplands are widespread throughout the country and improving their productivity is vital to attaining food security.

More than a hundred soil scientists from various universities, government agencies, private companies and non-government organizations are expected to attend the three-day conference. In addition, some leading soil scientists from Australia, Canada, and Germany will be attending as plenary speakers.

The Department of Agronomy and Soil Science of VSU, a co-sponsor of the conference, will be organizing a pre-conference tour for those participants who will arrive early. The tour will enable the participants to observe the major soils in the central highlands of Leyte.

VSU can be reached via Ormoc City and Tacloban City. It takes about 30 minutes by car to reach VSU from Ormoc City and two hours from Tacloban City.

A comparison of organic and conventional farming

The Council for Agricultural Science and Technology (CAST) in the USA, assembled in 1980 a high-powered Task Force composed of 24 scientists (chaired by S.R. Aldrich) with expertise in agricultural economics, agronomy, animal science, dairy science, entomology, food science, horticulture, soil science, veterinary medicine and others to look into the similarities and differences between organic and conventional farming. The Task Force report, which remains very relevant to the current debate surrounding organic and conventional agriculture, was officially published as CAST Report No. 84 "Organic and Conventional Farming Compared" in October 1980.

Some of the interesting highlights of the report are:

1. Conventional and organic farming have much in common. They differ principally in the use of modern chemical technology. Conventional farmers use commercial inputs (fertilizers, pesticides, animal feed additives) to increase productivity while organic farmers prefer to use natural resources.

2. Both conventional and organic farmers use various mechanical, biological, and other means to control pests. Conventional farmers use synthetic pesticides but organic farmers prefer to avoid them.

3. Conventional farmers extensively use nutritional supplements in animal feeds, hormonally active substances, and drugs. These substances are generally unacceptable to organic farmers.

4. The terms "natural" and "organic" are often used interchangeably in organic farming. But in science, organic refers to carbon compounds. Many such compounds occur in nature and many are synthesized in laboratories and factories. Likewise, many inorganic or nonorganic compounds occur naturally. Hence, natural compounds are not necessarily organic, and organic compounds are not necessarily natural.

5. Urea is a natural organic waste product of human and animal metabolism. It is present in animal and human excreta and is therefore accepted as a natural and nonartificial nitrogen source in organic farming. However, the urea that is synthesized in factories which is chemically identical to the urea produced by human and animal metabolism (used as fertilizer in conventional farming), is not acceptable in organic farming. This is one of the inconsistencies in organic agriculture.

6. The urea produced by animals (present in excreta) or by factories (in commercial fertilizers) is transformed in the soil into ammonium and nitrate ions, the important forms of nitrogen taken up by plants. Both ions are inorganic, not organic. Therefore, in scientific terminology, the organically grown food produced with urea derived from animals is actually "inorganically grown."

7. The "organic foods" produced by organic farming are composed of chemicals. Most foods contain many chemicals, and most of these are organic chemicals, whether the foods are produced by conventional farming or organic farming.

Favorite and influential soil science books

Below is my short article which appeared in the IUSS Bulletin 117 (Nov 2010) and 118 (June 2011) under the title "Favorite Soil Science Books."

Soil science is a rapidly growing ecological earth science. Consequently, the number of books on the subject has greatly increased in the last two decades. So to choose my top three soil science books, I thought of this criterion: the book must have been very useful to me when I was a student and it is still useful now in my research and teaching activities as a professor of soil science. The criterion automatically disqualifies some very good books that I used as a student but for various reasons I seldom or do not use them today as well as some outstanding soil science books published in recent years but were not yet available during my student days.

My first choice is the Properties and Management of Soils in the Tropics by Pedro A. Sanchez published in 1976 by John Wiley and Sons. It discusses in a simple but in-depth manner the tropical environment (climate, vegetation types, geology, land use and farming systems); the classification of tropical soils using Soil Taxonomy, FAO and some other important systems; the physical and chemical properties, clay mineralogy, and exchange processes of tropical soils; soil acidity and liming; soil nutrients and fertility evaluations; and soil management under different tropical land use systems. This outstanding book certainly belongs to the most important and influential books on tropical soils. I still use it regularly and even require my graduate students to read certain parts of it.

My second choice is Tropical Soils. A Comprehensive Study of their Genesis by E.C.J. Mohr, F.A. van Baren, and J. van Schuylenborgh (3rd revised edition) published in 1972 by Mouton-Ichtiar Baru-Van Hoeve. The book has three parts. Part I deals on the fundamentals of climate, rock and mineral weathering, and organic matter transformation. Part II discusses oxisols, leteritic soils, podzolic soils and podzols, vertisols, paddy soils, and andosols. Part III covers the experimental and physico-chemical study of soil-forming processes. I find it an excellent and unique book on tropical soils because of the coverage and details in which the topics are presented. It has been very useful to me especially during my masteral and doctoral studies (we used it for the course on tropical soils in Hohenheim). I still consult this book often which is an important part of my personal library.

My third choice is the standard soil science textbook in German-speaking countries, the Scheffer/Schachtschabel Lehrbuch der Bodenkunde (Textbook of Soil Science) now in its 16th edition (Spektrum Academisches Verlag). The book has undergone several revisions under different teams of authors. The latest edition was prepared by H.P. Blume, G.W. Bruemmer, R. Horn, E, Kandeler, I. Koegel-Knabner, R. Kretzschmar, K. Stahr, and B.M. Wilke, all leading soil scientists. It covers the origin and development of soils; physical, biological and chemical properties of and processes in soils; nutrients and contaminants; soil systematics and geography; soils and soil landscapes of Europe and the world; soil evaluation and protection. It is an excellent textbook for students who understand German. I find it also a vital reference for my research and teaching activities.