RESEARCH INTERESTS:

Soil management and cropping systems, integrated nutrient management, root/soil interface phenomena, nutrient cycling., characterization of active soil C and N pools; denitrification potential associated with root induced carbon flux, tracer techniques to elucidate nutrient depth distribution and root architecture impact on crop N utilization and C deposition. Agricultural systems and soil C-sequestration potential.

EXTENSION INTERESTS:

Extension activities include presentations regarding nutrient management in manured systems with emphasis on reducing phosphorus load to surface water. Also carbon sequestration and energy efficiency issues associated with cropping and tillage systems.

COURSES TAUGHT:

• AGRO SOIL 269 Principles of Soil Management
• AGRO HORT 424/824 Plant Nutrition and Nutrient Management
• AGRO NRES 966 Root Soil Interface Modeling

MAJOR PROJECT ACTIVITIES:

1. Carbon sequestration in irrigated and dryland maize agroecosystems.
2. Derivation of heterotrophic and autotrophic components of soil CO2 respiration using stable isotope techniques.
3. Nitrogen turnover in mobile and chemically protected humic acid fractions as influenced by long-term cropping and tillage practice
4. Full C-cycle analysis of intensive maize production systems.
5. Impacts of intensive maize management on yield components and environmental quality.
6. Phosphorus losses in runoff as influenced by manure management and manure quality.
7. Characterization of N mineralization and availability in crop systems.

SELECTED PUBLICATIONS:

• Suyker, A.E., S.B. Verma, G.G. Burba, T.J. Arkebauer, D.T. Walters, and K. G. Hubbard. 2004. Growing season carbon dioxide exchange in irrigated and rainfed maize. Agriculture and Forest Meteorology (in press).
  
  
• Yang, H.S., A. Dobermann, J.L. Lindquist, D.T. Walters, T.J. Arkebauer, K.G. Cassman. 2004. Hybrid-maize - a maize simulation model that combines two crop modeling approaches. Field Crops Res 87:131-154.
  
  
• Cassman, K.G., A. Dobermann, D.T. Walters, and H.S. Yang. 2003. Meeting cereal demand while protecting natural resources and improving environmental quality. Annual Review of Environment and Resources 28: 315-358.
  
  
• Cassman, K, A. Dobermann and D.T. Walters. 2002. Agroecosystems, nitrogen management and economics. Ambio 31(2):132-140.
  
  
• Vogel, K., J. Brejda, D.T. Walters, and D.R. Buxton. 2002. Switchgrass biomass production in the midwest: harvest and nitrogen management. Agron. J. 94:413-420.
  
  
• Cowling, E., J.N. Galloway, C.S. Furiness, M. Barber, T. Bresser, K. Cassman, J.W. Erisman, R. Haeuber, R. Howarth, J. Mellilo, W. Moomaw, A. Mosier, K. Sanders, S. Seitzinger, S. Smeulders, R. Socolow, D. Walters, F. West, and Z. Zhu. 2002. Optimizing nitrogen management in food and energy production and environmental protection: summary statement from the second international nitrogen conference. In Optimizing Nitrogen Management in Food and Energy Production and Environmental Protection: Proceedings of the 2nd International Nitrogen Conference on Science and Policy. The Scientific World 1(S2), 1-9.
  
  
• Yamoah, C.F., D.T. Walters, C.A. Shapiro, C.A. Francis, and M.J. Hayes. 2000. Standardized precipitation index and nitrogen rate effects on crop yields and risk distribution in maize. Agriculture, Ecosystems and Environment 80:113-120.
  
  
• Binder, D., D.H. Sander, and D.T. Walters. 2000. Maize response to time of nitrogen application as affected by level of nitrogen deficiency. Agronomy Journal 92:1228-1236.
  
  
• Bundy, G., D.T. Walters and A.E. Olness. 1998. Evaluation of Soil Nitrate Tests for Predicting Corn Nitrogen Response in the North Central Region. NC Reg. Res. Rpt. WI Agr. Expt. Sta.
  
  
• Walters, D.T. and J. Goesch. 1998. Temporal and spatial variability in soil nitrate acquisition by maize as influenced by nitrate depth distribution. 12pp. Proc. 4th Intl. Conf. on Precision Agriculture. July 19-22, 1998 St. Paul, MN. ASA/CSSA/SSSA, Madison, WI
  
  
• Kessavalou, A. and D.T. Walters. 1997. Winter Rye as a cover crop following soybean under conservation tillage. Agronomy J. 89:68-74
  
  
• Qian, J.H., J.W. Doran, and D.T. Walters. 1997. Maize plant contribution to root zone available carbon and microbial transformations of nitrogen. Soil Biol. Bioch. 29:1451-1462

MISCELLANEOUS INFORMATION:

Member:

• American Society of Agronomy
• Soil Science Society of America
• International Soil Science Society
• Sigma Xi
• Gamma Sigma Delta

Spanish: Spoken - Good, Written - Good

Recent Invited Presentations:

June 1-2, 2001 "Intensification of irrigated maize systems: Carbon sequestration potential and the relationship to climate change". (Keynote address) presented at the International Symposium on Intensively Managed Agroecosystems and Climate Change University of Navarra, Pamplona, Spain.

Oct 8-12, 2001 "Quantifying Carbon Sequestration in Intensively Managed Agroecosystems" presented at the Joint U.S.-Japan Workshop on Carbon Management in Terrestrial Ecosystems. Tokyo, Japan.

Nov 12-14, 2002. "Carbon Budget of Irrigated and Dryland maize Production Systems" Evaluation of Terrestrial Carbon Storage and Dynamics. Center for Basinc Ecosystem Studies, Gifu Univ., Gifu, Japan.

April 22-23, 2004. "Estrategias para alcanzar los maximos redimimientos de maiz: Fertilizacion y otros practicas de manejo" Keynote address presented the symposium "Fertilidad 2004 - Fertilidad de Suelos para una Agricultura Sustentable" Rosario, Argentina.