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.