mortiz085

Students of soil science are taught that to determine the amount of soil organic matter, soil organic carbon is measured usually by wet oxidation using potassium dichromate (called Walkley-Black method) or in well-equipped laboratories, using CN analyser and then multiplied by a conversion factor of 1.72 or 1.724. Most textbooks and laboratory manuals do not explain how this factor was obtained, so students generally accept the value without any question just like they do with other constants used in natural sciences.  Origin of the conversion factor The conversion factor has a very long history and has practically survived the test of time and modern analytical methods. It is about 150 years old. It was based on studies in the 1820s by the famous agricultural chemist, Carl Sprengel of Goettingen University, that organic matter contains 58 percent carbon. But it was another leading agricultural chemistry pioneer, Emil Wolff from Hohenheim, who introduced the value of 1.724 in 1864....

Contributed by Dr. Ian A. Navarrete Humboldt Fellow Soil Science of Tropical and Subtropical Ecosystems Buesgen Institute University of Göttingen, Germany Geoecology, a term coined some 41 years ago by the geomorphologist Carl Troll who was at the time professor at the University of Bonn, Germany, is a broad integrative term to the study of forms and functions of terrestrial geoecosystem (Huggett, 1995). It emphasizes the interdependency and/or inter-relationships of the ecological biosphere with landscape and hence sometimes equated with landscape ecology. For example, the movement and distribution of solutes across soil landscapes are influenced by the geomorphic position in the soil within the landscape thus influencing soil genesis (Sommer and Schlichting, 1997) and vegetation development (Huggett, 1975).  Fig 1. Relation of primary forest and grasslands of Samar During our fieldwork at the Samar Island Natural Park (along the Paranas-Taft road at about 300 m above sea level) i...