Jack Bremner: A Heritage for Understanding Soil Nitrogen, Organic Matter and Biomass.

John M. Bremner (Jack) a Scottish native completed a university degree with honors in chemistry at Glasgow.  His professional career was divided into two temporal parts:  the first 13 years at Rothamsted in England, and the last 35 at Iowa State University.  He spent extended study periods in Germany, Austria, Yugoslavia, Australia and Japan during his career.  At Rothamsted he realized that he needed new procedures and techniques better to study soil organic matter, so he developed, tested and published them along with a new understanding of the chemical nature of soil organic matter emphasizing the role of nitrogen.  He adopted chromatography as a key tool for chemical studies, and honed his skill in identifying the critical questions and planning experiments to answer them.  Surrounding himself with talented students and local and international scientific colleagues in Iowa, his laboratory continued the characterization of soil organic matter, employing N-15, and expanded its investigations to include sulfur and phosphorus as well as nitrogen transformations. This led to an understanding of nitrogen and sulfur losses from soils, and also the sorption of compounds from the atmosphere.  The laboratory demonstrated that nitrous oxide is lost during nitrification of ammonium, and that volatilization of organic compounds of sulfur predominates over hydrogen sulfide in sulfur loss from soil.  These studies led to the role of extracellular enzymes from the biomass in transformations occurring in soil organic matter and a clearer relation of these losses to fertilizer nitrogen use.  His chemical methods were consolidated and published in monographs, making them globally available.  The students and scientific colleagues who listened to his instruction and were guided in his laboratory represent a direct living influence that continues today.