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Donald G. McGahan – Professor

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I am interested in identifying systematic variation in soil morphology and soil genesis using relationships with climate, vegetation and biological organisms, geomorphology, and geology. As a soil morphologist I utilized multiple low and high technology tools to investigate soil and soil mineralogical alterations brought about by the soil forming factors. Mineralogical alterations are the primary cause of many important values we measure in soils. By studying the alteration of minerals and considering the evolution of soils (a very slowly renewable resource), relationships vital to addressing landscape scale issues are better understood. This knowledge of soil “in the environment” and “of the environment” is applicable to site-specific soil management(s) including both land use for agricultural, and land use for non-agricultural soils and soil uses. Furthermore, I operate under the premise that understanding soil is also vital to conservation of many other natural resources.

COURSES OFFERED

Undergraduate

  • SOIL3301 Soils (Fall and Spring Semesters)
  • SOIL3101 Soils Laboratory (Fall and Spring)
  • SOIL3302 Soils and Land Use (Even Numbered Fall Semesters)
  • SOIL3412 Soil Genesis and Classification (Odd Numbered Fall Semesters)
  • SOIL4450 Soil Nutrient Cycling (Soil Fertility) (Even Numbered Spring Semesters)
  • SOIL2112 Soil Morphology and Soil Judging (Fall Semester)
  • WSES4088 Undergraduate Research (Fall or Spring Semester)
  • SOIL4212 Soil Ecology (Odd Spring Semesters)
  • SOIL4213 Soil Physical Properties (ODD Spring Semester)

Graduate

  • WSES5320 Advanced Topics in Ecosystem Biogeochemistry 
  • WSES5350 Pedology 

RESEARCH AND SCHOLARLY ACTIVITIES

Research Activities

  • McGahan, Donald G, “Vineyard Soil and Nutrient Survey,” Sponsored by Tarleton State University, Tarleton State University, $8,604.00. (October 26, 2010 – August 1, 2011).
  • McGahan, Donald G, Mitchell, Forest L., Brady, Jeff. “Texas Pierce’s Disease Research and Education Program,” Sponsored by USDA -APHIS, Federal, $120,888.00. (April 1, 2010 – March 31, 2011).
  • McGahan, Donald G., Cummings, Hennen, Wittie, Roger D., James, Muir P., Michael, Maurer , Jamie, Foster, Lloyd, Nelson, Gerald, Evers, “Dwarf turf-type and early maturing annual ryegrass to establish perennial vegetation,” Sponsored by Texas Department of Transportation, State, $200,523.00.
  • McGahan, Donald G, “Vineyard Soil and Nutrient Survey,” Sponsored by Tarleton State University, Tarleton State University, $6,992.00. (October 26, 2009 – August 1, 2010).
  • McGahan, Donald G., Brady, Jeff, Faske, Travis R. “Evaluating Zinc Supplementation for Management of Pierce’s Disease,” Sponsored by USDA-APHIS-Southern Region IPM Center, Federal, $24,998.00. (April 1, 2009 – March 31, 2010).
  • McGahan, Donald G., Wittie, Roger D. “Interagency Cooperation Agreement,” Sponsored by USDA-Natural Resource Conservation Service, Federal, $15,000.00. (September 1, 2008 – August 31, 2009).

PUBLICATIONS

Refereed Publications

Non-Refereed Publications

Presentations

  • McGahan, D. G., Tabor N. J. The ASA-CSSA-SSSA International Annual Meetings, “Modern Soil Analogs of Carbonate Chemistry and Genesis in Paleosols,” American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Pittsburgh, PA. (November 1-5, 2009).
  • McGahan, D. G,. Shlemon Specialty Conference – The Geological Assessment of Naturally Occurring Hazardous Substances, “Soil Physical Conditions Influence Soil Chemical Environment,” The AEG Foundation and The Association of Environmental & Engineering, Folsom, CA. (July 5, 2008).
  • McGahan, D. G,. Southard, R. J. , Claassen, V. P,. The ASA-CSSA-SSSA International Annual Meetings, “Serpentinite Mineralogical Variation Impact on Vegetation Ca:Mg Ratios,” American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Salt Lake City, Utah. (November 7, 2005).
  • McGahan, D. G,. Southard, R. J,. Claassen, V. P,. American Association for the Advancement of Science: Pacific Division, “Does Serpentinite Mineralogical Variation Affect Clay Mineralogy, Soil Mineralogical Class, and Ca:Mg Ratios?,” American Association for the Advancement of Science: Pacific Division, Ashland, OR. (June 13, 2005).
  • McGahan, D. G,. Southard, R. J,. Claassen, V. P,. The ASA-CSSA-SSSA International Annual Meetings, “A Lithosequence on Serpentinitic Parent Material: Degree of Serpentinization,” American Society of Agronomy, Crop Science Society of America and Soil Science Society of America, Seattle, WA. (November 2, 2004).
  • McGahan, D.G.,. Southard, R..J.,. Claassen, V.P.,. Soil Characteristics Affect Plant Establishment on an 11-Year-Old Serpentinite Road Cut in California. American Association for the Advancement of Science: Pacific Division. San Francisco, CA. 2:1:68 June 15-19 2003. p.68
  • McGahan, D.G.,. Southard, R..J.,. Zasoski R..J.,. Rhizosphere and Bulk Soil Solution Comparison and Mineral Stability. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Annual Meeting; Agronomy Abstracts. Salt Lake, UT; (October 31 – November 4, 1999) p.206.
  • McGahan, D.G..,. Southard, R..J.,. Trioctahedral Phyllosilicates in a Serpentinite-Derived Vertisol. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Annual Meeting; Agronomy Abstracts. Baltimore, MD; (October 18-22, 1998) p.321.
  • McGahan, D.G.,. Southard, R..J.,. Zasoski, R..J.,. Mineralogical Comparison of Agriculturally-acidified and Naturally-acidic Soils. American Association for the Advancement of Science: Pacific Division. San Francisco, CA. 18:1:68 (June 19-23. 1998).
  • McGahan, D.G.,. Southard, R..J.,. Claassen, V.P.,. Soil Characteristics Affect Plant Establishment on an 11-Year-Old Serpentinite Road Cut in California. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Annual Meeting; Agronomy Abstracts. Denver, CO; (November 2-6, 2003) p.68.
  • Murashkina-Meese, M,. McGahan, D,., Rasmussen, C,. Southard, R.J., , Pettygrove, G.S,. Potassium fixation potential predicted from SSURGO data in soils of the San Joaquin Valley, California. American Society of Agronomy, Crop Science Society of America and Soil Science Society of America Annual Meeting. Indianapolis, IN. (November 10-14, 2002).
  • Rasmussen, C,. McGahan, D.G.,. Pettygrove, G.S,., Murashkina-Meese, M,. Southard, R.J,. Use of SSURGO to identify potentially K-fixing soils. 6th International Conference on Precision Agriculture. Minneapolis, MN. (2002) p.53.
  • Southard, R,. Macalady, J,. S. Ewing , Hartshorn, T,. Johnson, M,. Neumann, R,. McGahan, D,. Tuli, A,. and Brostrom, P,. Spatial Distribution of Soil C, N, and Microbial Communities in a Mojave Desert Creosote Bush (Larrea tridentata) Ecosystem, California. American Association for the Advancement of Science: Pacific Division. San Francisco, CA. 18:1 (June 19-23, 1999) p.68.

DEGREES

  • Ph.D. Soils and Biogeochemistry – University of California, Davis
  • M.S. Soil Science – University of California, Davis
  • B.S. Soil and Water Science – University of California, Davis
  • A.S. Mathematics and Physical Science – American River College

GRADUATE GROUP MEMBERSHIPS

  • Tarleton State University Graduate Faculty Status
  • Texas A&M University System Graduate Faculty Status