Paul W. Brown

Associate Director, Programs; Extension & Research Specialist
Building/Room: 
Saguaro Hall, 312A & Forbes 301
Address: 

Department of Soil Water and Environmental Science
The University of Arizona
P.O. Box 210038
Tucson, Arizona 85721-0038

Office Phone: 
(520) 621-7205
Fax: 
(520) 621-1647

Ph.D. 1981. Soil Science/Minor in Meteorology. University of Wisconsin at Madison.
M.S. 1979. Soil Science. University of Wisconsin at Madison.
B.S. 1977. Atmospheric Science. University of Missouri at Columbia.

2005: Environmental and Water Resources Institute Award for Task Committee Excellence American Society of Civil Engineers.
2001: Faculty of the Year Award. Arizona Ag 100 Council.
1999: Extension Faculty of the Year. University of Arizona

July 1995 to present. Extension Specialist & Research Scientist-Biometeorology. Department of Soil, Water and Environmental Science. University of Arizona, Tucson, AZ.

July 1990 to July 1995. Associate Extension Specialist & Research Scientist-Biometeorology. Department of Soil, Water and Environmental Science. University of Arizona, Tucson, AZ.

June 1985 to July 1990. Associate Extension Specialist-Biometeorology. Department of Soil, Water and Environmental Science. University of Arizona, Tucson, AZ.

April 1981 to May 1985. Senior Research Biologist, Senior Research Specialist and Research Group Leader. Monsanto Agricultural Products Co., St. Louis, MO.

 

Research interests rest in the general area of agricultural or biological meteorology. Specific areas of interest include: crop water requirements, plant water relations, soil physics, salinity management and the impact of thermal stresses on biological systems.

Water & Salinity Management: High Maintenance Desert Turf Systems

Research is focused on developing best management practices for irrigation of high maintenance desert turf systems. Current projects include studies to: 1) quantify the water requirements of desert turfgrass systems, 2) use electromagnetic induction as a non-destructive means of assessing soil salinity on golf course fairways, 3) quantify the water loss due to evaporation and drift off target from commercial turf irrigation heads, and 4) evaluate turf quality and the potential for salinization when turf is irrigated in accordance with ADWR water duties.

Impact of Heat Stress on Cotton Reproductive Development
The objectives of this work are to: 1) define the thermal environment that leads to heat stress in cotton, 2) delineate the stage of reproductive development most sensitive to heat stress, and 3) quantify the impact of heat stress intensity and duration on subsequent reproductive development. Studies have been conducted in growth chambers, greenhouses and the field over the course of five years. Results to date reveal increased abortion of flowers when mean crop temperatures rise above 28oC for the day. High rates of abortion, resulting from floral abnormalities, develop when mean crop temperatures exceed 30oC. The stage of reproductive development most sensitive to heat stress is when developing square (flower buds) is about 10 days from bloom. Heat stress does not produce significant square abortion; instead, heat damaged squares complete development, bloom and then abort 3-5 days after flowering. Crop temperatures can be modeled with reasonable accuracy by using both air temperature and humidity. A cotton heat stress model and has been developed as a result of this work and output from the model is available daily via the AZMET Internet site.

Siting of Automated Weather Stations: Impact on Estimates of Evapotranspiration
This study seeks to quantify the impact of fetch conditions adjacent to automated weather stations on computed values of reference evapotranspiration (ETo). This study is being carried out along the Lower Colorado River in conjunction with the Bureau of Reclamation (BR). BR plans to use ETo computed from weather stations to help assess water use along the Colorado River. Poor weather station siting can lead to serious overestimates of ETo which in turn lead to overestimates vegetation water use along the River. The objectives of this study are to: 1) quantify the impact of poor station siting on ETo, 2) develop improved siting criteria for automated weather stations used to estimate ETo, and 3) examine possible techniques that can be used to adjust meteorological data acquired from poor weather sites for use in estimating ETo.

Quantifying the Water Requirements of Crops in the Lower Colorado River Valley
This objective of this work is to develop new information on the water requirements of crops grown in the Lower Colorado River Valley. Very few quantitative water use studies have been completed since the USDA last summarized crop water use in the early 1980s. Four weighing lysimeters have been installed in Yuma Valley that can measure water use to within ~0.1 mm. Current funded studies are examining the water use of lettuce and wheat. The results from these studies will be used to develop new consumptive use curves as well as crop coefficients that can be used with reference evapotranspiration to estimate crop water use in near real time. Additional crops will be evaluated at the conclusion of these initial studies.

Journal Articles
 

Brown, P.W. 2008. Cotton Heat Stress. Ext. Rpt. AZ1448. College of Agriculture & Life Sci., Univ. of Arizona, Tucson, AZ.

Brown, P.W. 2008. Turfgrass Consumptive Use: Mohave County, Arizona. Ext. Rpt. AZ1447. College of Agric. & Life Sci. Univ. of Arizona. Tucson, AZ.

Brown, P.W. 2006. Evaluation of ADWR Water Duties for Large Turf Facilities. Turf Irrigation Management Series: No. 9. Ext. Rpt.1381. College of Agriculture & Life Sci., Univ. of Arizona, Tucson, AZ.

Brown, P.W. 2005. Fall Precipitation Assessment. Report Submitted to the Arizona Cotton Research and Protection Council & Arizona Department of Agriculture. 19p

Brown, P.W. 2005. Standardized Reference Evapotranspiration: A New Procedure for Estimating Reference Evapotranspiration in Arizona. Ext. Rpt.1324. College of Agricultural & Life Sci., Univ. of Arizona, Tucson, AZ.

Popular Publications

Brown, P.W. 2006-Present. Southeast Arizona Crop Water Use Report. Published Weekly from 1 April - 30 September. Internet Publication: http:ag.arizona.edu/azmet. 4p.

Brown, P.W. and B. Russell. 2002-Present. Statewide Heat Stress Report. Produced Daily From 1 May through 30 September for the following locations: Aguila, Marana, Pinal Co., Parker, Yuma Valley, Safford, Paloma, Queen Creek, Mohave Valley, Cochise Co., Harquahala, Eloy, Coolidge, Maricopa and Buckeye. Internet Publication: http://ag.arizona.edu.

Brown, P.W. and B. Russell. 2002-Present. Colorado River Heat Stress Report. Produced Daily From 1 May through 30 September for the following locations: Aguila, Marana, Pinal Co., Parker, Yuma Valley, Safford, Paloma, Queen Creek, Mohave Valley, Cochise Co., Harquahala, Eloy, Coolidge, Maricopa and Buckeye. Internet Publication: http://ag.arizona.edu.

Brown, P.W. and B. Russell. 2001-Present. Cotton Planting Date Advisories. Produced Weekly From 1 March through 1 May for the following locations: Aguila, Marana, Pinal Co., Parker, Yuma Valley, Safford, Paloma, Queen Creek, Mohave Valley, Greenlee Co., Cochise Co., Harquahala, Eloy, Coolidge, Maricopa and Buckeye. Internet Publication: http://ag.arizona.edu.

Brown, P.W. and B. Russell. 2001-Present. Cotton Development Advisories. Produced Weekly From 1 May through 31 August for the following locations: Aguila, Marana, Pinal Co., Parker, Yuma Valley, Safford, Paloma, Queen Creek, Mohave Valley, Greenlee Co., Cochise Co., Harquahala, Eloy, Coolidge, Maricopa and Buckeye. Internet Publication: http://ag.arizona.edu.

Brown, P.W. 2008. Mapping Salinity in Golf Course Soils Using Electromagnetic Induction. Proceedings of 2008 Karsten Turf Field Day. 15 May 2008. Univ. of Arizona, Tucson, AZ

Brown, P.W. 2007. Irrigation Scheduling of Turfgrass. 2007 Desert Turf School. University of Arizona, Tucson, AZ

Brown, P.W. 2007. Landscape Water Use Estimates for Payson, Arizona. Class Handout for AGR 230 Gardening & Landscape. Gila Community College, Payson, AZ.

Brown, P.W. 2007. Monthly Adjustment Factors for Irrigation Controllers in Payson, Arizona. Class Handout for AGR 230 Gardening & Landscape. Gila Community College, Payson, AZ.

Brown, P.W. 2007. Payson Landscape Irrigation Guide. Class Handout for AGR 230 Gardening & Landscape. Gila Community College, Payson, AZ.

Brown, P. 2007. The El Nino Winter of 2006/07?? Proceedings of 41st Annual Conference of Western Pecan Growers Assn. 4-6 March 2007. Las Cruces, NM. p.18.