Plant Physiology & Genetics Research Unit
USDA-ARS, Arid-Land Agricultural Research Center
Ph.D. Soil Physics, Cornell University, 1970
M.S. Soil Physics, Iowa State University, 1965
B.S. Soil Physics, University of Minnesota, 1963
Have studied the movement of soil heat and soil gases and have developed several new analysis and measurement methods. However, most of professional career have studied the effect of CO2 on plant growth and water relations. At the beginning, focused on exploitation of CO2 enrichment to increase agricultural productivity in closed greenhouses for arid regions. But for the last two decades, have determined the effects of the increasing atmospheric CO2 concentration and climate change on yield and water use of outdoor field crops. Have assembled and analyzed the published literature on this topic, as well as the likely effects of global change on water resources. Have led or co-led large cooperative multi-variate experiments using open-top chambers (OTC) and free-air CO2 enrichment (FACE) to expose field-grown crops to elevated CO2, including sour orange, cotton, wheat, and sorghum. Besides management role, was responsible for the measurement of canopy microclimate, energy balance, and evapotranspiration.
Most recently, have been trying to establish the feasibility of ecosystem warming experiments, especially with infrared heaters in order to study the effects of global warming, along with elevated CO2, on open-field plots. A hexagonal array of such heaters produces very uniform warming over 3-m-diameter plots. Interest in this arrays is high and collaborative experiments are underway at Haibei, Qinghai, China and at Cheyenne, Wyoming, USA. And in March, 2007 we launched a "Hot Serial Cereal" experiment here at Maricopa, AZ; wherein arrays of infrared heaters are suspended over open-field plots of wheat that is being planted every six weeks for a 2-year period.