Kenneth G. Cassman


·CGIAR website

Kenneth Cassman

Emeritus Robert B. Daugherty Professor of Agronomy

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

Area of Focus

Food security and yield gap analysis at local, global and spatial scales

Research Interests

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 while protecting environmental quality and conserving natural resources provides the central theme of my work. It is estimated that food production must double on existing farmland by 2050 to provision 9+ billion people with an adequate diet while protecting rain forests, wetlands, and savannahs from conversion to agriculture. Moreover, agricultural systems must also help solve the most serious environmental problems facing humankind (climate change, conservation of biodiversity, pollution) because agriculture 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 efforts focus on a global collaboration to develop the Global Yield Gap Atlas ( that provides state-of-the-art estimates of the gap between current average farm yields and the potential yield ceiling for major food crops throughout the world. The Atlas supplies essential information to guide development policies and research prioritization at global and national scales while also supporting efforts to identify yield constraints and technologies to overcome them at local to regional levels.

Educational Interests

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.


  • Laurance WF, Sayer J, and Cassman KG. 2014. Agricultural expansion and its impact on tropical nature. Trends in Ecol. Evol.29:107-116.
  • Cassman KG and Grassini P.  2013.  Can there be a green revolution in Sub-Saharan Africa without large expansion of irrigated crop production?  Global Food Security 2: 203-209.
  • Grassini P, Eskridge KM, and Cassman KG. 2013. Distinguishing between yield advances and yield plateaus in historical crop yield trends. Nat. Commun. 4:2918. doi:10.1038/ncomms3918
  • Van Wart J, Grassini P, Cassman KG. 2013.  Impact of derived global weather data on simulation of crop yields. Global Change Biol. 19: 3822-3834.
  • Sayer J and Cassman KG. 2013. Agricultural innovation to protect the environment. PNAS 101:8345-8348.
  • Van Ittersum M,K., Cassman K.G., Grassini, P., Wolf, J. Tittonell, P., Hochman, Z.  2013.  Yield gap analysis with local to global relevance-A Review. Field Crops Res.  143: 4-17
  • Grassini P and Cassman KG.  2012.  High yield maize with large net energy yield and low global warming potential. Proc. Natl. Acad. Sci.  109:1074-1079.
  • 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.
  • 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.
  • 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.
  • 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.