A Tribute to Robert J. Soper
Professor Emeritus, Dept. of Soil Science, University of Manitoba
by Geza Racz and Don Flaten
Robert J. Soper passed away on July 20, 2016. Bob was a professor in the Dept. of Soil Science at the University of Manitoba from 1958 to 1991. His research career spanned a wide range of topics in soil chemistry, soil fertility and crop production. Of particular note was his outstanding work on nitrogen and phosphorus nutrition in crops.
Bob was one of a team of pioneers to develop and use radioactive phosphorus in crop nutrition studies in the field. This early work showed the benefit of ammonium nitrogen for improving phosphorus uptake in plants and helped establish ammonium phosphate as the best phosphorus fertilizer for the Canadian Prairies. Later, at the University of Manitoba, he elucidated the soil and crop factors that affected the uptake of fertilizer and soil phosphorus responsible for the varying yield response to fertilization by crops commonly grown on the prairies. The information from these studies was and still is used for crop nutrition recommendations.
Bob also became an internationally respected leader in the use of stable isotope-labelled nitrogen to measure nitrogen dynamics in soil and biological nitrogen fixation in legume crops. Bob’s contribution to the introduction of soil testing as a means of predicting the need for nitrogen fertilization of crops was extremely important. The test for soil available nitrogen was mainly developed by him and is used for agronomic and environmental purposes in Manitoba and most other regions of the North American Great Plains.
In addition to his work to improve nitrogen and phosphorus nutrition in crops, Bob also led studies on potassium, sulphur and zinc nutrition that are still used to form the basis of fertilizer recommendations for these nutrients.
Beyond his many important research achievements, Bob is also remembered warmly by his colleagues and students for his role as a thought-provoking teacher, mentor and supervisor. He provided students with inspiring ideas on experimental design, treatments, techniques and interpretation of data. In particular, his former graduate students remember him best for the friendly and collegial manner in which he supervised them, his keen mind and professor-student team approach to research.
Bob was recognized for his achievements in several ways. He received Western Canada’s Agronomy Merit Award and the Queen Elizabeth II Silver Jubilee Medal, and was named a Fellow of the Canadian Soil Science Society. Following his retirement, he was named Professor Emeritus at the University of Manitoba.
Bob will be long remembered and valued for his pioneering work on crop nutrition, soil testing and fertilizer recommendations, as well as his warm, bright and collegial relationships with colleagues and students.