Richards, L.A.

From HydroWiki

Between his birth on April 24, 1904 and his death in 1993, Lorenzo Adolph (L.A.) Richards would become one of, if not the most influential, soil physicist of the 20th century. Over the course of more than 35 years as a researcher in academia and for the federal government he revolutionized the field of soil physics. Notably, he developing an extension to Darcy’s law that described soil water movement in unsaturated soil, laid the groundwork for such instruments as the pressure membrane apparatus, and helped coin and standardize much of the soil physics terminology we use today (2). Outside of soil physics, he served the country in the Second World War and helped establish the United States Department of Agriculture Soil Salinity Laboratory in Riverside, California (1).

L.A. Richards grew up in Fielding, Utah, and obtained both his B.S. and M.A. at Utah State University in 1926 and 1927, respectively. He then moved to Cornell University, where he obtained his PhD in 1931 (1). It was during his M.A. and PhD period that he began laying out the framework for the equation that would eventually bear his name. In his M.A. thesis, titled “The usefulness of capillary potential to soil-moisture and plant interactions”, he urged extension of Darcy’s Law to unsaturated soil (2). He continued to expound on this theme in his PhD thesis, titled “Capillary conduction of liquids through porous mediums”, where he combined the equation of continuity as described by Buckingham with Darcy’s Law. These equations laid the foundation for what would eventually be called the Richards Equation, a non-linear differential equation for describing water movement in unsaturated soil (3), which is commonly used in hydrologic models today.

In addition to his pioneering work in describing water movement in unsaturated soil, his research included improving ways to measure capillary and total soil water potential (2). Richards developed the framework for the pressure membrane apparatus to measure soil moisture and with the help of others, described the range of pressures within which soil water was available to plants. In addition to the pressure membrane apparatus, Richards developed other measurement devices, including a portable salinity bridge, salt sensor, modulus of rupture apparatus and water flux meter (2).

More broadly, Richards contributed to the terminology of soil physics, maintaining that scientific concepts can evolve no more rapidly than the words used to describe them (2). He published papers on soil water terminology, and went so far as to organize a discussion at the International Soil Science Congress in 1960, which created a committee to consider and recommend soil water terminology (2).

Outside of soil physics, Richards served his country in World War Two by helping to develop the automatic rocket launcher, and spent a six-month tour in the pacific theater as a technical advisor (1). In addition to his research activities, while a faculty member at Iowa State University he taught both classical and soil physics (1). Throughout his career he received numerous awards both for his work in soil physics and for his military contributions. These included a Presidential Certificate of Merit in 1948 for his military contributions and an USDA Superior Service Award in 1959 and an honorary Doctorate in Technological Sciences from the Hebrew Institute of Technology in 1952 for his scientific work (1).

More than any other single individual, Richards developed experimental soil water physics into a quantitative laboratory science (2). His development of equations, measurement methods and terminology rapidly advanced the field and laid the groundwork for a generation of research to come. His work, particularly his equations describing soil water movement became a fundamental part of many hydrologic models.

Figure 1. Picture of Lorenzo A. Richards

References

(1) Bower, C.A. 1972. In Recognition of L.A. Richards on the Occasion of his 68th Birthday. Soil Sci. 113: 229-231.

(2) Gardner, W.R. 1972. The Impact of L.A. Richards Upon the Field of Soil Water Physics. Soil Sci. 113: 232-237.

(3) Richards equation. (2007, December 30). In Wikipedia, The Free Encyclopedia. Retrieved January 19, 2008, from http://en.wikipedia.org/w/index.php?title=Richards_equation&oldid=180947449