I earned a BS and MS in Soil Science from Texas A&M University and a PhD in Soil Physics from New Mexico State University. I joined the faculty at Iowa State University in 1981 and am a Distinguished Professor of Soil Science. I teach three soil physics courses and a scientific communication course. I am a Fellow of the Soil Science Society of America, and I received their Soil Science Research Award. I am also an Honorary Professor at China Agricultural University, and I was a Senior Visiting Professor of the Chinese Academy of Sciences.
The focus of my research is heat, water, and chemical movement in soil. Theory has been developed to describe these processes mathematically. The theory has been applied to predict soil temperature, soil water evaporation and drainage, and nitrogen leaching from the root-zone. Current research projects include coupled heat and water movement in hydrophobic soil, colloid-facilitated transport of hormones in soil, bio-fuel cropping system impacts on soil, water, and air, and heat pulse probe measurements of soil water evaporation.
My research includes coupled heat and mass transfer theory development, instrument development, and field measurements. My theory has been incorporated into soil, plant, atmosphere models. I am named on three patents for instruments or technologies related to measuring soil water movement and reducing soil nitrogen leaching. My measurements have led to new understanding of the role of soil water evaporation and soil water fluxes. The broad impacts of my research are to increase basic knowledge of and applications of soil heat and mass transfer processes.
Nassar, I. N., and R. Horton. 1999. Transport and fate of volatile organic chemicals in unsaturated, non-isothermal salty porous media: I. Theoretical development. J. Hazardous Materials 69:151-167
Casey, F. X. M., S. K. Ong, and R. Horton. 2000. Degradation and transformation of trichloroethylene in miscible-displacement experiments through zero-valent metals. Environmental Science and Technology 34:5023-5029
Gaur, A., R. Horton, and D. B. Jaynes. 2006. Measured and predicted solute transport in a tile drained field. Soil Science Society of America Journal 70: 872-881
Xiao, X., R. Horton, T.J. Sauer, J.L. Heitman, and T. Ren. 2011. Cumulative soil water evaporation as a function of depth and time. Vadose Zone Journal 10:1016–1022