Soil Scientist and Research Leader
Great Plains Systems Research Unit
Natural Resources Research Center
2150 Centre Avenue, Building D, Suite 200
Fort Collins, CO 80526-8119
970-492-7312
Laj.Ahuja@ars.usda.gov

1954	B.S. (Honors) Agronomy/Chemistry. University of Delhi, India.
1961	M.S. Soil and Water Management/Chemistry. Indian Agricultural Research Institute, New Delhi, India.
1968	Ph.D. Soil Physics. University of California, Davis, CA

1991-Present	Research Leader, USDA-ARS, Great Plains Systems Research, Fort Collins, CO. Faculty Affiliate, Colorado State University
1979-91	Soil Scientist, USDA-ARS, National Water Quality Lab, Durant, OK
1976-78	Associate Soil Scientist/Associate Professor, University of Hawaii, Hilo, HI
1972-76	Assistant Soil Scientist, University of Hawaii, Honolulu, HI
1968-71	Research Associate, Purdue University, West Lafayette, IN

Invited special lecture and award by Korean Society of Soil Science, 1983

USDA-ARS fellowship for research and study at Princeton Univ., 1985-86

Certificate of Merit in recognition of outstanding/exemplary research, productivity, and quality, USDA-ARS, 1987 and 1989. Exemplary Leadership of GPSR, 1997; GPFARM Release, 2002.

Scientist of the Year Award, USDA-ARS, Southern Plains Area, 1989

Elected Fellow, SSSA, 1994; ASA, 1996

Outstanding Scientist of the Year, Association of Agricultural Scientists of Indian Origin, 2002

Invited international academic advisor of the Yucheng Experiment Station, Chinese Academy of Sciences, 2003

Sr. Scientist of the Year Award, USDA-ARS, Northern Plains Area, 2003

Don and Betty Kirkham Soil Physics Award, Soil Sci. Soc. of Amer., 2004

IAEA expert in the Republic of Korea for soil water research. May to August 1983

Consultations on soil physics at the Natl. Res. Institute of Agri. Eng. Tsukuba, and Okayama University, Japan, August - September 1983.

USDA Consultant to India on models and PI 480 projects. June, 1987

Associate Editor, 1987-92; Tech. Editor, 1994-96; Soil Sci. Soc. Am. J.

Expert to FAO on modeling chemigation. Cairo, Egypt, Sept. 1991

Organized ARS workshop on Real World Infiltration, 1996

Consultation and workshop on Root Zone Water Quality Model, Swiss Federal Institute for Environ. Sci. & Tech. (EAWAG), Zurich, Sept. 1998

NRCS-ARS-CSREES Partnership Management Team, 1995-present

ARS Technical Expert on infiltration soil water movement, 1995-present

Member steering committees/workshops for ARS Water Quality & Mgmt., Integrated Agric. Systems, and Global Climate Change National Programs 1998-2000. Co-Leader, ARS models, decision tools, and databases

Led a team of 4 colleagues to China to provide advice and training on using RZWQM and GPFARM to 60+ scientists. October 2002

Topic Editor, Encyclopedia of Soil Science, 2002. Guest Editor, Special Issue of Geoderma. 2003

Chair, 21-member Task Force, Great Plains Agricultural Council, that organized a workshop on Computer Applications in Water Mgmt. 1995

Organized Interagency Intern. Workshop on development of a Modular Modeling Framework for agricultural systems, 1997.

Organized international symposia “Use of Agricultural System Models in Field Research, Technology Transfer, and Decision Support”, ASA 2000, Mpls., MN and “Quantifying management effects on soil properties and processes”, SSSA 2001, Charlotte, NC

Organized an international workshop on “Applications, enhancements, and collaborations of RZWQM and GPFARM,” April 20-22, 2004. Fort Collins, CO

Organizing symposium for the 18th World Soil Science Congress on “Synthesis, modeling, and applications of disciplinary soil science knowledge for soil-water-plant-environment systems”. Philadelphia, 2006

Delivered guest lectures on modeling, and served on MS and Ph. D. thesis committees of 6 graduate students, Colorado State University

Conducted workshops and provided trainings on using the ARS Root Zone Water Quality Model (RZWQM) to 15+ groups. RZWQM book and software commercialized through Water Resources Publications; sold 1000+ copies worldwide

Ahuja $5000 Fellowship for students using ag system models in research, 2005.

Brought in $650,000 in new permanent funding and $1,000,000 soft money to GPSR and Object Modeling System.

Discovered a mathematical similarity and a dimensional transformation for infiltration into crusted soils and developed new simple power-form equations and Green-Ampt type models.

Analyzed pathways of subsurface flow of water/chemicals in sloping layered soils to estimate contributing areas.

Developed an accelerated diffusion model and a non-uniform mixing model for estimating chemicals in runoff being used in EPA and industry models.

Developed several new simpler methods of determining soil hydraulic properties and their spatial variability for applications. Discovered a method to estimate both water retention curve and saturated conductivity from bulk density and field capacity, and a more general method to relate soil-water properties across dissimilar soil types.

New research on quantifying management effects on soil properties and processes. A model of preferential transport of surface-applied chemicals to groundwater through macropores; role of surface soil aggregation on this chemical transport; new models on how tillage and reconsolidation change soil water retention curve; differences in chemical leaching between crop row and inter-row zones; and effect of surface residue cover on rainwater infiltration.

Development and national/international evaluation of ARS Root Zone Water Quality and GPFARM Decision Support System models.

1. Ma, L., Ahuja, L.R., Ascough II, J.C., Shaffer, M.J., Rojas, K.W., Malone, R.W., and Cameira, M.R. Integrating system modeling with field research in agriculture: Applications of the Root Zone Water Quality Model (RZWQM) Advances in Agronomy. 71:233-292. 2000.
2. Ruan, H., Ahuja, L.R., Benjamin, J.G., and G, 2003. Green T.R. Residue cover and crusting effects on infiltration: Simulations for field applications. Soil Sci. Soc. Am. J. 65:853-861. 2001.
3. Ahuja, L.R., Guest Editor, Special Issue of Geoderma on Agricultural Management Effects on Soil Properties and Processes. Geoderma 116: 1-248. 2003.
4. ⁴Andales, A.A., Ahuja, L.R. and Peterson, G.A. Evaluation of GPFARM for dryland cropping systems in Eastern Colorado. Agron. J. 95: 1510-1524. 2003.
5. ⁴Kozak, J. A., and Ahuja, L. R. Scaling of infiltration and redistribution across soil textural classes. Soil Sci. Soc. Am. J. Accepted, Nov. 2004

Refereed Journals - 150+
Book Chapters - 26
Books Edited - 4
Proceedings - 75

A keynote speaker, First Joint Congress of the Soil Sci. Soc. Am. – German Soil Sci. Soc. on landscape processes. Sept. 2000.

"Agricultural System Models in Field Research and Technology Transfer,” 2nd International Agronomy Congress, Nov. 2002, New Delhi, India.

“Water balance—The Influence of a Residue Layer and Tillage on infiltration, Water Holding Capacity, and Evaporation,” Intl. Workshop on Modeling Effects of Residue and Tillage. CIMMYT, Mexico. Dec. 2003.

“The GPSR Program and RZWQM & GPFARM Models,” Lawrence Livermore Natl. Lab. Oct. 2004

Res. Hydrologic Engineer
Great Plains Systems Research Unit
Natural Resources Research Center
2150 Centre Avenue, Building D, Suite 200
Fort Collins, CO 80526-8119
970-492-7371
Jim.Ascough@ars.usda.gov

1982	B.S. Agricultural Engineering, Purdue University, West Lafayette, IN.
1985	M.S. Agricultural Engineering, Purdue University, West Lafayette, IN.
1992	Ph.D. Agricultural Engineering (Civil Engineering Minor), Purdue University, West Lafayette, IN.

1994-Present	Res. Hydraulic Engineer, USDA-ARS GPSR, Fort Collins, CO
1992-94	Post-Doc (Ag. Engineer), USDA-ARS NSERL, West Lafayette, IN.
1989-92	Research Associate, USDA-ARS NSERL, West Lafayette, IN.

USDA-ARS Cash Award ($2000) and Certificate of Merit for Outstanding Work for the Water Erosion Prediction Project (WEPP), 1988

USDA-ARS Certificate of Merit Awards for Unusual and Creative Erosion Prediction Research, 1991; Outstanding Performance for Contributions to Development of WEPP, 1995

USDA-ARS Cash Award ($1000) and Certificate of Merit for Outstanding Leadership for the Great Plains Framework for Agricultural Resource Management (GPFARM) Project, 1998

Outstanding Technical Reviewer: 1) Transactions ASAE (1997, 1999); 2) Computers and Electronics in Agriculture (1998, 2001, 2003)

USDA-ARS Certificate of Merit Award for Outstanding Contribution to the Successful Development and Release of GPFARM Version 2.0, 2002.

Served as consultant to the engineering firm Simon and Associates of Fort Collins, Colorado. Assisted their engineers with the application of the RUSLE erosion model to mined areas. 1994, 1999.

Associate Editor, Transactions ASAE (Soil and Water Division). 2000-02.

Associate Editor, J. Soil Water Conservation. 2004-present.

Conservation Effects Assessment Project (CEAP) team member for the “Modularization, Integration, and Development of Improved Regionalized Watershed Models for Future Assessments at Different Scales” sub-project. 2003-present.

Organizing Committee Member for the Inter-Agency Workshop on the Development of a Modular Modeling Framework, USDA ARS/NRCS and USGS, Fort Collins, Colorado. 1997.

Northern Plains Area GIS Technical Representative (Alternate) 2002-present.

Organized international symposium on “Sensitivity Analysis, Uncertainty Analysis, and Parameter Estimation for Agronomic Models” at the 2004 ASA-SSSA-CSSA meetings, Seattle, WA.

Organizing two symposiums on sensitivity analysis and agricultural decision support system development for MODSIM05, Melbourne, Australia. December 2005.

Lane, L.J. and J.C. Ascough II. 1989. Prototype Expert System for Design and Evaluation of Shallow Landfill Burial Systems Using a Knowledge-Based/Numerical Modeling Approach. USDOE-LANL/USDA-ARS Interagency Agreement DE-AI32-90AL64110. $115,000.

Hoag, D.L. and J.C. Ascough II. 1998. Development of Profit and Loss (PAL) Farm Budgeting Economic Software for Colorado Agriculture. Colorado State University Experiment Station/CSU Extension Service. $15,000.

Dr. Ascough provided scientific leadership as well as a significant part of the scientific content for the WEPP model, one of the most advanced soil erosion prediction tools existing in the world today. As part of the WEPP development team Dr. Ascough originated the overall WEPP model framework, led programming for the initial WEPP hillslope model development effort, and developed the program structure and majority of subroutines in the WEPP watershed model.

Dr. Ascough was one of the first to use survey results in conjunction with DSS requirements analysis. A large number of producers and agricultural advisors in the Great Plains region were surveyed about use of computers and decision support technology in their agribusinesses. This was the most comprehensive survey of United States agricultural computer use in the past decade, and was critical in identifying types of information producers and agricultural advisors require for supporting management decisions on farms and ranches.

Dr. Ascough was one of the first to conceptualize and initiate the application of project management and system engineering principles to agricultural DSS development. Dr. Ascough’s design and development of the GPFARM GUI, farm/ranch economics module, and multicriteria/indices decision analysis modules are seminal advancements in DSS component technology, and point to new directions for future DSS research and development. GPFARM (and its successor iFARM) are currently the only DSSs to provide farm-level computerized decision support technology for evaluating the sustainability of integrated farm and ranch production systems.

Dr. Ascough and Dr. Ma’s sensitivity analysis and model evaluation techniques for the RZWQM and WEPP models, combining sensitivity analysis, first order error analysis, and Monte Carlo simulation with Latin Hypercube Sampling, produced new recommendations for evaluating water quality models and are universally applicable to all hydrologic and water quality simulation models.

1. Ascough II, J.C., Hoag, D.L., Frasier, W.M., and McMaster, G.S. 1999. Computer use in agriculture: An analysis of Great Plains producers. Comp. Elect. Agric. 23 (1999):189-204.
2. Ma, L., Ascough II, J.C., Ahuja, L.R., Shaffer, M.J., Rojas, K.W., and Hanson, J.D. 2000. Root Zone Water Quality Model sensitivity analysis using Monte Carlo simulation. Trans. ASAE 43(4):883-895.
3. Ascough II, J.C., Hoag, D.L., and Engler-Palma, A. 2002. The impact matrix approach and decision rules to enhance index dimensionality, flexibility and representation. J. Ecol. Indic. 2 (2002):161-168.
4. Ascough II, J.C., Hoag, D.L., McMaster, G.S., and Frasier, W.M. 2002. Computer use and satisfaction by Great Plains producers: Ordered logit model analysis. Agron. J. 94:1263-1269 (2002).
5. McMaster, G.S., Ascough II, J.C., Shaffer, M.J., Deer-Ascough, L.A., Byrne, P.F., Nielsen, D.C., Haley, S.D., Andales, A.A., and Dunn, G.H. 2003. GPFARM plant model parameters: Complications of varieties and the genotype x environment interaction in wheat. Trans. ASAE 46(5):1337-1346.

Refereed Journals – 27
Book Chapters – 6
Proceedings – 22
Extension Bulletins – 1
Abstracts – 32

SERSP-ARO-CEMML Workshop and Retreat on Landscape Evolution and Soil Erosion Modeling: Applications for Environments of Military Interest, Colorado State University and the U.S. Army, Loveland, Colorado. March 1-5, 1999. Invited presentation on “Applications of WEPP Watershed Technology on Military Lands.”

International Environmental Modelling and Software Society (IEMSS) 2002 Conference - Integrated Assessment and Decision Support, Lugano, Switzerland. June 24-27, 2002. Invited presentation on “Multicriteria Spatial Decision Support Systems: Overview, Applications, and Future Research Directions.”

Modelling and Simulation Society of Australia and New Zealand (MODSIM05) invited session organizer. Organizing dual sessions on “Sensitivity Analysis, Uncertainty Analysis, and Parameter Estimation in Natural Resource Modelling”, and “Agricultural Decision Support Systems - Useful Tools or Near Extinction?” December 2005.

Soil Scientist
Great Plains Systems Research Unit
Natural Resources Research Center
2150 Centre Avenue, Building D, Suite 200
Fort Collins, CO 80526-8119
970-492-7320
Gale.Dunn@ars.usda.gov

1977	B.S. Agronomy Colorado State University, Fort Collins, CO
1982	M.S. Soil Fertility Colorado State University, Fort Collins, CO
1991	Ph.D. Soil Physics University of Kentucky, Lexington, KY

1998-Present	Soil Scientist, Cat. 4, Great Plains Systems Research Unit
1992-1998	Soil Scientist, Cat. 3, Great Plains Systems Research Unit
1990-1991	Post Doc. National Sedimentation Laboratory, USDA-ARS, Oxford, MS
1987-1990	Research Associate, Agronomy Dept, University of Kentucky, Lexington, KY
1982-1987	Instructor, Agronomy Dept, Penn State University, University Park, PA

Certificates of Merit – April 1991, May 1995, November 1995

Certificates of Appreciation - March 1993, April 1993, January 1997, November 1998, January 2000, May 2002, November 2002, December 2003, March 2004

Gamma Sigma Delta

Sigma Xi

1998 – 2000 Larimer County Rural Land Use Board

Colorado Association of Wheat Growers – MOU

Decision Commerce Group – CRADA (pending)

Agren – CRADA (pending)

Colorado Wyoming Resource Team Outreach Program 2002-2004

Colorado Farm Show 2002, 2003 (GPSR)

Colorado Conservation Tillage Association 2000 – 2004 (GPFARM)

Colorado FFA Annual Meeting 2000 (GPFARM)

Golden Plains Maximum Economic Yield Group 2000-2003 (GPFARM, iFARM)

Colorado Precision Agriculture Field Days 2004 – Yuma and Fort Collins (GPFARM, iFARM)

Agren Inc./Risk Management Agency – Expert Panel Review 2004 (GPFARM, iFARM)

Colorado Association of Wheat Growers Board of Directors’ Meeting- 2003 (GPFARM)

Farm Credit of Colorado Board of Directors’ Meeting – 2004 (GPFARM)

GPFARM Training for Colorado Association of Wheat Growers – Limon, Burlington, and Sterling, CO, February 2004

Northwest Junior College Agricultural Instructors Seminar 2002 (GPFARM)

Guest Lecturer – SC377 GIS Applications Colorado State University, October 2004

Special Training for Agricultural Science Faculty, Training in the Use of GPFARM for Classroom Instruction, Colorado State University, December 2004.

1. Andales, A.A., J.D. Derner, P.N.S. Bartling, L. R. Ahuja, and G.H. Dunn. 2005. Evaluation of GPFARM for Simulation of Forage Production and Cow-Calf Weights. In Press.
2. McMaster, G.S., D.B. Palic, and G.H. Dunn. 2002. Soil management alters seedling emergence and subsequent fall growth and yield in dryland winter wheat-fallow systems in the Central Great Plains on a clay loam soil. Soil & Tillage Research. 65:193-206.
3. McMaster, G.S., J.C. Ascough II, G.H. Dunn, M.A. Weltz, M. Shaffer, D. Palic, B.C. Vandenberg, P. Bartling, D. Edmunds, D. Hoag, and L.R. Ahuja. 2002a. Application and testing of GPFARM: A farm and ranch decision support system for evaluating economic and environmental sustainability of agricultural enterprises. Acta Horticulturae 593:171-177.
4. Shaver, T. M., Peterson, G. A., Ahuja, L. R., Westfall, D. G., Sherrod, L. A., and Dunn, G. Surface soil physical properties after twelve years of dryland no-till management. Soil Sci. Soc. Am. J. 66:1296-1303. 2002.
5. Sherrod, L.A., G. Dunn, G.A. Peterson, and R.L. Kolberg. 2002. Inorganic Carbon Analysis by Modified Pressure-Calcimeter Method. Soil Sci. Soc. Am. J. 66:299-305.

Refereed Journals – 15
Book Chapters – 2
Proceedings – 8
Extension Bulletins – 2
Popular Articles – 2
Abstracts – 22

American Society of Agronomy Annual Meeting; Denver, CO; November 5, 2003. Application of GPFARM, a Whole-Farm Decision Support Model for Yield, Economic, and Environmental Forecasting.

International Conference on Herbal and Medicinal Plants; June 4-5, 2004; Djerba, Tunisia. Extension of GPFARM to Tunisian Arid Agricultural Systems

Colorado Conservation Tillage Association Annual Meeting; February 2002; Greeley, CO; GPFARM – Great Plains Framework for Agricultural Resource Management – an Overview

Colorado Conservation Tillage Association Annual Meeting; February 2003; Greeley, CO; A Case Study Using GPFARM – Selecting the Best Crop Rotation for the Soil Type

Hydrologic Engineer
Great Plains Systems Research Unit
Natural Resources Research Center
2150 Centre Avenue, Building D, Suite 200
Fort Collins, CO 80526-8119
970-492-7312
Tim.Green@ars.usda.gov

1986	B.S. Civil Engineering, University of Washington, Seattle, WA
1989	M.S. Civil Engineering/Water Resources, Stanford University, Stanford, CA
1995	Ph.D. Civil Engineering/Hydrology, Stanford University, Stanford, CA

1991-94	Hydrologist, USGS, Water Resources Division, Menlo Park, CA
1995-97	Research Scientist, CSIRO, Div. Water Resources, Perth, Australia 1997-98 Senior Research Scientist, CSIRO Land & Water, Perth, Australia
1998-present	Agricultural Engineer, USDA-ARS-GPSR, Fort Collins, CO

Hawaiian Trust Company, Marion M. Scott Scholarship, For promotion of world peace and international understanding and cooperation, 1982-83.

University of Washington, Civil Engineering, Henry Grey Merit Scholarship. Nominated by the faculty for one year’s full tuition, 1985.

Chi Epsilon, Civil Engineering Honorary, 1986.

American Geophysical Union, Horton Research Grant, One of two national awards to Ph.D. candidates for original research in hydrology, 1990.

American Society of Civil Engineers, Research Fellowship, National award for advanced doctoral research in Civil and Environmental Engineering, 1991.

USDA-ARS, Colorado/Wyoming Research Leaders Council, For unselfish dedication to team research and outreach efforts for the GPSR Unit, October 2000.

Member of western regional project W-1188 “Improved Characterization and Quantification of Flow and Transport Processes in Soils” (1999 to Present).

Guest Editor, Hydrological Processes, Special issue: Process Interactions in the Environment (1999).

Associate Editor, Vadose Zone Journal. (2001 to Present).

Invited member of an industry-led team of scientists, including Monsanto, Bayer, and USGS, exploring fractal scaling relationships of pesticide concentrations in streams (2001-2003). See Gustafson et al. (2004).

Invited Visiting Scientist at the University of Western Australia, Centre for Water Research, Perth, Australia concerning scaling of landscape processes. Per diem paid by UWA (3-8 December 2001).

Invited member of UNESCO International Hydrological Programme (IHP) panel of experts to conceive and define a new international project called GRAPHiC (Groundwater Resources Assessment under the Pressures of Humanity and Climate change), 2004-present.

Visiting Scientist at the ETH, Institute for Terrestrial Ecology, Zürich, Switzerland, January-July 2005. The ETH is fully supporting Dr. Green’s travel.

Precision Agriculture Field Day, Colorado State University Cooperative Extension, “Variable-rate planting on dryland fields: On-farm experiments”, 7 Aug 2002.

Young Farmers’ Association, Ault, Colorado, “Spatial measurements at the Drake Farm – Progress Report”, 27 March 2003.

American Geophysical Union, Horton Research Grant, 1991. ($9,500)

American Society of Civil Engineers, 1992. ($15,000)

NASA AirSAR Mission, Australia, 1996. ($15,000)

UNESCO International Hydrological Programme, 2004-2005. (Travel to Paris (3-5 March 2004) and England (April 2005) paid by IHP: approx. $3,000)

Swiss Federal Institute of Technology, Trust Fund Cooperative Agreement, 2005. (approx. $23,000 non-federal source)

Derived new stochastic/numerical results for moisture-dependent directional hydraulic conductivity, showing how soil heterogeneity and landscape undulations can cause preferred, unsaturated pathways for lateral convergence and deep drainage.

Developed an integrated approach for quantifying the movement of sediment and phosphorus in a large river basin by combining estimation methods, including streambank monitoring, radioactive tracers, aerial photography and computer simulation of sediment transport.

Simulated soil-plant water dynamics from climate scenarios, then derived statistical measures, including the temporal persistence, for assessing the potential impacts of forecasted climate change on groundwater recharge.

Identified spatial scaling relationships of crop yield, soil water, and landscape topography on newly instrumented farm fields using fractal geometry to characterize the behavior of observed variability across management scales.

A new Spatial Analysis Neural Network (SANN) method was developed for predicting spatial patterns of crop grain yield from topographic attributes. Effects of digital elevation accuracy and resolution on computed attributes, including potential flow accumulation, were evaluated as a corollary study.

1. Green, T.R., S.G. Beavis, C.R. Dietrich and A.J. Jakeman, 1999. Relating observed stream-bank movement to in-stream transport of suspended sediment, Hydrol. Process., 13(5):777-787.
2. Green, T.R., L.R. Ahuja, and J.G. Benjamin, 2003. Advances and challenges in predicting agricultural management effects on soil hydraulic properties in space and time, Geoderma, 116(1-2):3-27.
3. Gustafson, D.I., K.H. Carr, T.R. Green, C. Gustin, R.L. Jones and R.P. Richards, 2004. Fractal-based scaling and scale-invariant dispersion of peak concentrations of crop protection chemicals in rivers, Envirnomental Sci. & Tech. 38(11):2995-3003.
4. Martinez, A., J.D. Salas and T.R. Green, 2004. Sensitivity of spatial analysis neural network training and interpolation to structural parameters, Math. Geology, 36(6):721-742.
5. Green, T.R. and R.H. Erskine, 2004. Measurement, scaling, and topographic analyses of spatial crop yield and soil water content, Hydrol. Process. 18:1447-1465.

Refereed Journals – 13
Book Chapters – 5
Proceedings – 19
Extension Bulletins – 2
Popular Articles – 0
Abstracts – 38

University of Western Australia, Centre for Water Research, “Space-time soil water movement along an undulating hillslope transect”, 5 Dec 2001.

AGU Hydrology Days 2002, Fort Collins, CO, Special Session in Honor of Ignacio Rodriguez-Iturbe, “Space-Time Measurement of Soil Water and Simulation of Coupled Overland/Subsurface Flow In Undulating Terrain”, 3 Apr 2002.

University of Hawaii, Water Resources Seminar, “Spatial Crop Yield and Soil Water Content: Measurement, Scaling and Topographic Analyses”, 5 March 2003.

Integrative Modelling of Sustainable Land Use, Keynote talk: “Terrain-based scaling and simulation of cropping systems”, Zürich, Switzerland, 24-25 November 2003.

American Soc. Agronomy, “Model Parameters for Agricultural Systems with Nonlinear Process Interactions and Spatial Variability”, Section A03, Seattle, WA, 1 Nov 2004.

Soil Scientist
Great Plains Systems Research Unit
Natural Resources Research Center
2150 Centre Avenue, Building D, Suite 200
Fort Collins, CO 80526-8119
970-492-7339
Liwang.Ma@ars.usda.gov

1984	B.S. Biophysics, China Agricultural University, Beijing, China
1987	M.S. Biophysics, China Agricultural University, Beijing, China
1993	Ph.D. Soil Science, Louisiana State University, Baton Rouge, LA

1993-1996	Post-Doc, Agronomy Department, Louisiana State University, Baton Rouge, LA
1996-2000	Post-Doc, USDA-ARS-GPSR, Fort Collins, CO
2000-Present	Soil Scientist, USDA-ARS-GPSR, Fort Collins, CO

Outstanding Dissertation Award, College of Agriculture, Louisiana State University, 1993.

Served as a main contact for RZWQM users

Served as a guest research scientist for Chinese Academy of Sciences

Served as an Associate Editor for Soil Science Society of America Journal

Conducted several trainings on RZWQM in the U.S. and China (1998-2002)

OECD Fellowship for professional development leave to CSIRO, Toowoomba, Qld, Australia. 2004.

Developed a second-order reaction model for pesticide retention in soils.

Developed a mobile-immobile physical non-equilibrium model for pesticide transport in soils.

Enhanced the USDA-ARS Root Zone Water Quality Model (RZWQM) through the applications of RZWQM under a wide range of agricultural management systems around the world.

Developed hybrid models (RZWQM-DSSAT, RZWQM-SHAW) to enhance RZWQM simulations of various agricultural management practices.

1. Ma, L., Peterson, G. A., Ahuja, L. R., Sherrod, L., Shaffer, M. J., and Rojas, K. W. Decomposition of surface crop residues in long-term studies of dryland agroecosystems. Agronomy J. 91:393-401. 1999.
2. Ma, L., Ascough, J. C., II, Ahuja, L. R., Shaffer, M. J., Hanson, J. D., and Rojas, K. W. Root Zone Water Quality Model sensitivity analysis using the Monte Carlo simulation. Trans. ASAE. 43:883-895. 2000.
3. Nielsen, D. C., Ma, L., Ahuja, L. R., and Hoogenboom, G. Simulating soybean water stress effects with RZWQM and CROPGRO models. Agron. J. 94:1234-1243. 2002.
4. Ma, L., Nielsen, D. C., Ahuja, L. R., Malone, R. M., Anapalli, S. S., Rojas, K. W., Hanson, J. D., and Benjamin, J. G. Evaluation of RZWQM under varying irrigation levels in Eastern Colorado. Trans. ASAE. 46:39-49. 2003.
5. Saseendran, S. A., Nielsen, D. C., , Ahuja, L. R. and Halvorson, A.D. Modeling nitrogen management effects on a winter wheat cropping system using RZWQM and CERES-wheat. Agron. J. 96:615-630. 2004.

Refereed Journals – 46
Book Chapters – 12
Proceedings – 8
Extension Bulletins – 1
Abstracts – 30
Books edited - 4

Invited to visit and make presentations to CSIRO, Division of Land and Water in Canberra and Townsville, Australia and HortResearch in Palmerston North, New Zealand. 2004.

Invited to give a training/lecture on RZWQM at the University of Nebraska, Lincoln, Crop Modeling for Environment-Specific Management. November 2000

Invited to China by the Chinese Academy of Sciences to lecture on RZWQM and system modeling. October 2002.

Invited to give a lecture on RZWQM in the soil physics class at Colorado State University, April, 2004.

Research Agronomist
Great Plains Systems Research Unit
Natural Resources Research Center
2150 Centre Avenue, Building D, Suite 200
Fort Collins, CO 80526-8119
970-492-7340
Greg.McMaster@ars.usda.gov

1975	B.S. (Biology) Michigan State University, East Lansing, MI
1980	M.S. (Biology/Ecology) San Diego State University, San Diego, CA
1991	Ph.D. (Agronomy/Ecology) Colorado State Univ., Fort Collins, CO

1974 - 1975	Research Assistant, Michigan State University.
1974 - 1975	Teaching Assistant (Botany, Ecology) Michigan State University.
1977 - 1978	Teaching Assistant (Biostatistics), San Diego State University
1980 - 1982	Faculty Affiliate, Ecology/Biology Dept, San Diego State Univ.
1982 - present	Res. Agronomist, USDA-ARS-GPSR, Fort Collins, CO
1991 - present	Faculty Affiliate, Soil & Crop Sciences Dept, Colorado State University.

NRCS plaque expressing appreciation for “Outstanding contributions to natural resource conservation and erosion prediction in Colorado using the SHOOTGRO model”, 1995

Dow Fellowship in Ecology ($10,000) San Diego State Univ., 1977-1979

Chair-elect (2003), Chair (2004), Past-chair (2005) Plant Physiology and Metabolism Division of Crop Science Society of America

Associate Editor, Crop Science (2002-present)

Served on USDA NRI Plants and Environmental Adaptation panel (2004)

Crop Science Society of America International Crop Science Committee, 2003-present.

International Review Board, Annals of Botany, 1999-present.

Crop Science Society of America Growth Staging Ad Hoc Committee, 1994-1996.

Co-organizer of (1) CSSA symposium entitled “Opportunities for linking functional genomics with physiology for global change research” (co-editor and published in Field Crops Res.), (2) CSSA symposium entitled “Understanding development and growth in grasses: Role of the phyllochron concept” (published in Crop Sci.), and 3) ASA special session “Sensitivity Analysis, Uncertainty Analysis, and Parameter Estimation for Agronomic Models”.

Hosted (various time periods) visiting international scientists including from New Zealand, England, South Africa, Peoples Republic of China, Uzbekistan, Mexico, Czech Republic, Austria, Canada, and Australia.

Periodically serves as Panel Member for Research Promotion and Evaluation System.

Invited member of the Plant Ontology Consortium.

CRIS collaborator with Rangeland Resources Research Unit (Fort Collins, CO), Soil & Water Conservation Research Unit (Lincoln, NE), and Soil Management Research Unit (Morris, MN).

Participant in various ARS National Planning Workshops.

Working with CSU Extension and private industry to assist the Colorado Wheat Growers Association in altering the latest planting date allowed by the Risk Management Agency for crop insurances purposes.

Conservation Tillage Fact Sheet #4-97 “Optimum wheat stubble height to reduce erosion and evaporation” (published by USDA-ARS, NRCS, and Colorado Conservation Tillage Association), 1997.

Worked with NRCS to predict the amount of green winter wheat biomass expected entering winter to assist in determining farmer compliance with erosion mitigation measures for eligibility in government programs using the SHOOTGRO model. Work was distributed to Colorado field offices, and interest expressed in extending the work to Nebraska, Kansas, and New Mexico.

Invited instructor at the Colorado State University Extension Service Corn (1998) and Wheat (1997) Management Clinics.

Member of ARS/NRCS/Colorado State Univ. technical partnership group, 1994-1997.

Participate in activities such as the Colorado Conservation Tillage Association and field days, meet with farmer groups, conduct farmer interviews, and assist in surveying producers.

Colorado Wheat Research Foundation: $8000, “Determining the Latest Planting Date for Wheat Crop Insurance”, with J. Johnson and G. Meuhlbach, 2003-2005.

Colorado State Univ. Expt. Station: $97,690, “Improved heat and drought tolerance for Colorado wheat”, with five other scientists, 1999-2001.

Crop growth simulation models are increasingly being used to increase our scientific understanding and address agricultural problems. This team pioneered a new generation of development-centered crop simulation models (SHOOTGRO and SPIKEGRO).

Crop development is fundamental to understanding plant responses to the environment and management. Research conceptualized and quantified for the first time the entire developmental sequence of the winter wheat shoot apex and related this to growth stages. This template is successfully being applied to other crops (e.g., spring wheat, spring and winter barley, maize, sorghum, proso millet) and is being implemented into a separate computer program/submodel called Phenology MMS.

The phyllochron is key to understanding and predicting crop development. Research on the phyllochron includes co-organizing and publishing a Crop Science Society of America (CSSA) symposium “Understanding development and growth in grasses: Role of the phyllochron concept”; numerous publications, and performing a critical field experiment resulting in new insights that changed the existing paradigm. Subsequent efforts to better understand the genetic mechanisms controlling the phyllochron and other aspects of plant growth and development were explored by co-organizing a CSSA symposium entitled “Opportunities for linking functional genomics with physiology for global change research” published in Field Crops Research (co-editor and author on 4 papers).

Crop simulation models are rarely adopted by producers, and often technology transfer is limited from scientists to producers. Team research led to the development of the only whole-farm, comprehensive integrated farm and ranch strategic planning decision support system (GPFARM) for producers and agricultural consultants.

1. McMaster, G.S. Accepted 9/23/04. Centenary Reviews: Phytomers, phyllochrons, phenology and temperate cereal development. J. Agric. Sci., Camb. (Invited paper)
2. McMaster, G.S., J.C. Ascough, II, D.C. Nielson, P.F. Byrne, S.D. Haley, M.J. Shaffer, A.A. Andales, and G.A. Dunn. 2003. Using species-based plant parameters in GPFARM: Complications of varieties and the G x E interaction in wheat. Trans. Amer. Soc. . Agric. Eng. 46:1337-1346.
3. McMaster, G.S., and W.W. Wilhelm. 2003. Simulating wheat and barley phenological responses to water and temperature stress. J. Agric. Sci., Camb. 141:129-147. (Invited paper)
4. McMaster, G.S., W.W. Wilhelm, D.B. Palic, J.R. Porter, and P.D. Jamieson. 2003. Spring wheat leaf appearance and temperature: Extending the paradigm? Ann. Bot. 91:697-705.
5. McMaster, G.S., D.B. Palic, and G.H. Dunn. 2002. Soil management alters seedling emergence and subsequent fall growth and yield in dryland winter wheat-fallow systems in the Central Great Plains on a clay loam soil. Soil & Tillage Research. 65:193-206.

Refereed Journals – 43
Book Chapters – 3
Proceedings – 19
Extension Bulletins – 2
Popular Articles – 1
Abstracts – 60

Invited review paper on cereal development for centenary issue of J. Agric. Sci. Camb., 2005.

Invited paper on simulating cereal phenology J. Agric. Sci. Camb. (special issue) 2003.

Invited chapter “Wheat Growth and Development” in Colorado Wheat Production Handbook published by the Colorado Association of Wheat Growers, 2000.

Invited international seminars/consulting include Aberdeen, Scotland; CIMMYT, Mexico; Brno, Czech Republic; Vienna, Austria; Toowoomba, Australia; Christchurch, New Zealand; and Clermont-Ferrand, France

Computer Scientist
Great Plains Systems Research Unit
Natural Resources Research Center
2150 Centre Avenue, Building D, Suite 200
Fort Collins, CO 80526-8119
970-492-7316
olaf.david@ars.usda.gov

1989		B. S. Computer Science. Technical University of Ilmenau, Germany.
1991	M.S. Measurement Systems, Software-Technology, Computer Science, Friedrich-Schiller-University Jena, Germany.
1995	Ph.D. Computer Science, Friedrich-Schiller-University Jena, Germany

1991-Present	Research Scientist Colorado State University/Great Plains Systems Research, Fort Collins, CO.
1995-2000	Assistant Professor, Friedrich-Schiller-University Jena, Institute of Geography, Dept. of Geo-Informatics, Germany
1993-1995	Research Associate, Technical-University Ilmenau, Germany
1991-1993	Research Associate, Friedrich-Schiller-University Jena, Germany

Colorado-Wyoming Resource Team Award for Promoting Interagency Collaboration

European Community Project IWRMS: “Development of an innovative computer based Integrated Water Resource Management System (IWRMS) in semiarid catchments for water resource analysis and prognostic scenario planning“ (Information system architecture design, modularization of the ACRU model and integration into OMS). Since September 1997

European Community Project “Applied Remote Sensing and GIS Integration for Model Parameterization” (Designing a RDBMS/XML based remote sensing “method pool”) since January 1998

Third-party funded project “Internet based Interactive Visualization of geodata“ since 1998, Project Manager

Third-party funded project: “Development of a relational data model for interagency information systems”. since 1999, Project Manager

VW Project: “Impact of Large Scale Afforestation” ,South African Foundation for Research Development and University of Natal at Pietermaritzburg. since September 1997. (Object-oriented restructuring of the ACRU Model)

Third-party funded project “Design and Implementation of a RDBMS based monitoring station information system in Thueringen/Germany “ since 1999-2000 Project Manager.

European Community Project: An Advance Study Course in Water Resources Management in Arid and Semiarid Regions using Advanced Earth Observation and GIS Techniques. since 2000, (lecture in modelling techniques)

Conducting the Development of the ‘Object Modeling System’, a framework for environmental model development and application.

Conducting a pilot interagency research project “GEOLEM” in 2003/2004 about the development of a “Geospatial Object Library For Environmental Modeling”, establishing a SCA with Prof. Salas/Prof. Garcia, Dept of Civil Engineering.

Member of the “Memorandum of Understanding” MOU working on “Multimedia Environmental Models” between USDA, EPA, DOE, PNL, COE, USGS

Coordinating model integration for the ARS/NRCS CEAP-Watershed initiative by collaborating with ARS several research units involved in simulation model development (2003 – 2007).

Support the USDA/NRCS effort for the development of a “engineering toolbox” for NRCS field offices nationwide.

GPSR CRIS “iFarm” integration of Object Modeling System.

Analyzed the design and implementation of major simulation models for the development of a generic modeling framework, the Object Modeling System OMS.

Developed and applied the component – oriented principles in software technology to the design of environmental simulation models using the Object Modeling System.

Applied component method to several hydrological and agricultural simulation models such as the Root Zone Water Quality Model (RZWQM), or the Precipitation Runoff modeling system (PRMS).

1. U. Taddei, David O., Michl Ch.,: Application of VisAD in Hydrological Modeling and Simulation, ACM SIGGRAPH Computer Graphics, Vol 34. (1) pp 48-51, 2000.
2. O. David, S.L. Markstrom, K.W. Rojas, L. A. Ahuja, and I.W. Schneider: The Object Modeling System, In: Agricultural System Models in Field Research and Technology Transfer, L. Ahuja, L. Ma, T.A. Howell, Eds., Lewis Publishers, CRC Press LLC, 2002: 317—331.
3. S.L. Markstrom, G. McCabe, O. David: Web based distribution of geo-scientific models. Computers and Geosciences, Elsevier, 28 (2002) 577-581.
4. Ahuja, L.R., David, O., and Ascough II, J.C. 2004. Developing natural resource models using the Object Modeling System: Feasibility and challenges. International Environmental Modeling and Software Society (IEMSS) 2004 Conference – Complexity and Integrated Resources Management, Osnabrück, Germany. June 14-17. Vol. 1. p. 409-414.
5. O. David, R. J. Viger, I. W. Schneider, and L. Garcia: “Geospatial Interoperability in Modeling Frameworks - The ‘GEOLEM’ Approach”, International Environmental Modeling and Software Society (IEMSS) 2004 Conference – Complexity and Integrated Resources Management, Osnabrück, Germany. June 14-17. Vol. 1. p. 420-427.