Kenneth G. Cassman Robert B. Daugherty Professor of Agronomy
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Area of Focus
Independent Science and Partnership Council of the CGIAR
- B.S., Biology, University of California-San Diego, 1975
- M.S., Agronomy and Soil Science, University of Hawaii, 1977
- Ph.D., Agronomy and Soil Science, University of Hawaii, 1979
Soil fertility and plant nutrition; crop ecophysiology and yield potential; crop water productivity; nutrient cycling processes; soil quality and sustainability of intensive cropping systems; global food security.
Major Project Activities
The need to meet food demand without degrading environmental quality and natural resources provides the central theme of my work. It is estimated that food production must double by 2050 to provision 9+ billion people with an adequate diet. To protect rain forests, wetlands, and savannahs from conversion to agriculture, the additional food supply cannot come from expansion of crop and livestock production area. Moreover, agricultural systems need to contribute pro-actively to solving the most pressing environmental problems facing humankind (climate change, conservation of biodiversity, pollution) because agriculture is occupies 33% of the earth's terrestrial surface and uses 70% of all developed freshwater. Hence, the goal of my research is to find ways to increase crop yields substantially without compromising the quality of soil and water resources or damaging the integrity of natural ecosystems—a process called ecological intensification. Current work focuses on understanding how to achieve crop yields that approach the genetic yield ceiling (called potential yield) with highest possible efficiencies in use of water, nutrients, and energy. Crop simulation models (www.hybridmaize.unl.edu, http://soysim.unl.edu/) and life cycle assessment (www.bess.unl.edu) are important tools supporting this work. Another major effort involves a global collaboration to develop a Global Yield Gap Atlas (www.globalyieldatlas, the website will be up later this year) that provides best available estimates of the gap between current average farm yields and the potential yield ceiling for the major food crops. The Atlas provides critical information to guide development policies and research prioritization at global and national levels, while it also supports yield gap analysis at local to regional levels to identify major limiting constraints to increased food production.
Without a formal teaching responsibility, my primary educational role is supervision of graduate students and postdoctorals. I also enjoy contributing invited lectures to a wide range of courses in Agronomy, Agricultural Economics, Natural Resource Science, Engineering, and other majors. In outreach I remain active contributing to cooperative extension education activities with a focus on use of crop models as decision-support tools to achieve ecological intensification in crop production systems while also optimizing profits.
- Connor D, Loomis RS, Cassman KG. 2011. Crop Ecology. Cambridge University Press, Cambridge UK. 2nd Edition. 556pp
- Chen XP,1, Cui ZL, Vitousek PM, Cassman KG, Matson PA Bai JS, Menga QF, Hou P, Yue SC, 2011. Römhelde V, and Zhang FS. Integrated soil–crop system management for food security. Proc. Natl. Acad. Sci. www.pnas.org/cgi/doi/10.1073/pnas.1101419108.
- Grassini P, Yang H, Irmak S, Thornburn J, Burr C, Cassman KG. 2011. High-yield irrigated maize in theWestern U.S. Corn Belt: II. Irrigation management and crop water productivity. Field Crops Res. 120:133-144.
- Grassini P, Thornburn J, Burr C, Cassman KG. 2011. High-yield irrigated maize in theWestern U.S. Corn Belt: I. On-farm yield, yield potential, and impact of agronomic practices. Field Crops Res. 120:142-152.
- Cassman KG, Grassini P, van Wart J. 2010. Crop yield potential, yield trends, and global food security in a changing climate. pp. 37-51. In Rosenzweig C and Hillel D (eds): Handbook of Climate Change and Agroecosystems. Imperial College Press, London.
- Setiyono TD, Cassman KG, Specht JE, Dobermann A, Weiss A, Yang H, Conley SP, Robinson AP, Pedersen P, De Bruin JL. 2010. Simulation of soybean growth and yield in near-optimal growth conditions. Field Crops Res. 119:161-174.
- Lobell DB, Cassman KG, Field CB. 2009. Crop yield gaps: their importance, magnitudes, and causes. Annu. Rev. Environ. Resour. 34:179-204.
- Liska AJ, Yang HS, Bremer VR, Klopfenstein TJ, Walters DT, Erickson GE, Cassman KG. Improvements in Life Cycle Energy Efficiency and Greenhouse Gas Emissions of Corn-Ethanol. 2009. J. Industrial Ecol. 13:58-74.
- C assman K.G. and Liska A. J. 2007. Food and fuel for all: Realistic or foolish? Biofuels Bioprod. Biorefin. 1:18-23. http://www3.interscience.wiley.com/cgi-bin/fulltext/114283521/PDFSTART.
- Cassman K.G. 2007. Can organic agriculture feed the world—science to the rescue? Renewable Agric. Food Sys. 22:83-83.
- Olk, D.C, Cassman, K.G., Schmidt-Rohr, K., Anders, M.M., Mao, J.D., Deenik, J.L. 2006. Chemical stabilization of soil organic nitrogen by phenolic lignin residues in anaerobic agroecosystems. Soil Biol. Biochem. 38:3303-3312.
- Haishun Y., Dobermann A., Cassman K.G., and Walters D.T. 2006. Features, Applications, and Limitations of the Hybrid-Maize Simulation Model. Agron. J. 98:737-748.
- Cassman, K.G. and Wood, S. 2005. Cultivated Systems. pp 741-789 In Millennium Ecosystem Assessment: Global Ecosystem Assessment Report on Conditions and Trends. Island Press, Washington D.C. http://www.maweb.org//en/products.global.aspx.
- Verma, S.B., Dobermann, A., Cassman, K.G., Walters, D.T., Knops, J.M., Arkebauer, T.J., Suyker, A.E., Burba, G.G., Amos, B., Yang, H.S., Ginting, D., Hubbard, K.G., Gitelson, A.A., Walter-Shea, E.A. 2005. Annual carbon dioxide exchange in irrigated and rainfed maize-based agroecosystems. Agric. Forestry Meteorol.
- Peng, S, Huang J, Sheehy JE, Laza R, Visperas RM, Zhong X, Centeno GS, Khush G, Cassman KG. 2004. Rice yields decline with higher night temperature from global warming. Proc. Natl. Acad. Sci. (USA) 101: 9971-9975.
- Nguyen Bao Ve, Olk, D.C., and Cassman, K.G. 2004. Characterization of two humic acid fractions improves estimates of soil N mineralization kinetics in for tropical lowland rice. Soil Sci. Soc. Am. J. In Press. 87:1266-1277.
- Cassman, K.G., Dobermann, A., Walters, D.T., Yang, H. 2003. Meeting cereal demand while protecting natural resources and improving environmental quality. Annu. Rev. Environ. Resour. 28: 315-358.
- Tillman, D., Cassman, K.G., Matson, P.A., Naylor, R. and Polasky, S. 2002. Agricultural sustainability and intensive production practices. Nature 418: 671-677.
- Cassman, K.G., Dobermann, A., and Walters, D. 2002. Agroecosystems, nitrogen-use efficiency, and nitrogen management. AMBIO 31:132-140.
- Cassman, K.G. 2001. Crop science research to assure food security. In Noesberger, J. et al. (eds) Crop Science: Progress and Prospects. CAB International, Wallingford, UK. pp. 33-51.
- Cassman, K.G. 1999. Ecological intensification of cereal production systems: Yield potential, soil quality, and precision agriculture. Proc. National Acad. Sci. (USA) 96: 5952-5959.
- Cassman, K.G., S. Peng, D.C. Olks, J.K. Ladha, W. Reichardt, A. Dobermann, and U. Singh. 1998. Opportunities for increased nitrogen-use efficiency from improved resource management in irrigated rice systems. Field Crops Res. 56:7-39.
- Brouder, S.M. and K.G. Cassman. 1994. Evaluation of a mechanistic model of potassium uptake by cotton in a vermiculitic soil. Soil Sci. Soc. Amer. J. 58:1174-1183.
- Cassman, K.G., P.W. Singleton, and B.A. Linquist. 1993. Input/output analysis of the cumulative soybean response to phosphorus on an ultisol. Field Crops Res. 34:23-36.
- Cassman, K.G., B.A. Roberts, and D.C. Bryant. 1992. Cotton response to residual fertilizer potassium as influenced by organic matter and sodium in a vermiculitic soil. Soil Sci. Soc. Am. J. 56:823-830.
- Cassman, K. G., D. N. Munns, and D. P. Beck. 1981. Phosphorus nutrition of Rhizobium japonicum: strain differences in phosphate storage and utilization. Soil Sci. Soc. Am. J. 45:517-520.
- Cassman, K. G., and D. N. Munns. 1980. Nitrogen mineralization as affected by soil moisture, temperature, and depth. Soil Sci. Soc. Am. J. 44:1233-1237.