G. Philip Robertson

G. Philip Robertson

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University Distinguished Professor
Department of Plant, Soil and Microbial Sciences



B.A., Hampshire College
PhD, Indiana University, Biology

Overview of current program:

We study the sustainability of field crop ecosystems with a focus on ecosystem services related to their productivity and biogeochemistry. We study food crops (primarily corn, soybean, and wheat) as well as cellulosic biofuel crops (including switchgrass, miscanthus, and restored prairie), and consider both conventional and alternative management strategies, including reduced input and organic. We are particularly interested in questions of nitrogen availability  and loss, soil carbon dynamics, and fluxes of the greenhouse gases CO2, nitrous oxide, and methane.  Our studies range in scale from the microbial to landscapes and regions. We ask fundamental questions of topical importance: our research informs the design of resource-efficient high-yielding cropping systems, strategies to reduce nitrogen pollution from agricultural landscapes, and national greenhouse gas mitigation policies.

Web Links:

Recent Publications:

(Full list of publications)


Chipkar, S., K. Kahmark, S. Bohm, M. Z. Hussain, L. Joshi, K. M. Krieg, J. Aguado, J. Cassidy, P. Lozano, K. Garland, A. Senyk, D. J. Debrauske, E. Whelan, M. Davies, P. Urban, G. P. Robertson, T. K. Sato, S. K. Hamilton, K. D. Thelen, and R. G. Ong. 2024. High temperatures and low soil moisture synergistically reduce switchgrass yields from marginal field sites and inhibit fermentation. GCB Bioenergy 16:e13119. [PDF]

Robertson, G. P. and P. M. Groffman. 2024. Nitrogen transformations. Pages 407-438 in E. A. Paul and S. D. Frey, editors. Soil Microbiology, Ecology, and Biochemistry, 5th edition. Elsevier, Cambridge MA. [PDF]


Grandy, A. S. and G. P. Robertson. 2023. Managing soils as systems in temperate-region landscapes. Pages 45-54 in N. Uphoff and J. Thies, editors. Biological Approaches to Regenerative Soil Systems. CRC Press, Boca Raton FL. [PDF]

Guo, T., S. T. Marquart-Pyatt, and G. P. Robertson. 2023. Using three consecutive years of farmer survey data to identify prevailing conservation practices in four Midwestern US states. Renewable Agriculture and Food Systems 38:E44. [PDF]

Hussain, M. Z., S. K. Hamilton, and G. P. Robertson. 2023. Soil phosphorus drawdown by perennial bioenergy cropping systems in the Midwestern US. GCB Bioenergy 15:254-263. [PDF]

Jayawardena, D. M., G. P. Robertson, G. R. Sanford, and K. D. Thelen. 2023. Comparative productivity of six bioenergy cropping systems on marginal lands in the Great Lakes Region, United States. Agronomy Journal 115:2451-2468. [PDF]

Kim, S., B. E. Dale, R. A. Martinez-Feria, B. Basso, K. Thelen, C. T. Maravelias, D. A. Landis, T. J. Lark, and G. P. Robertson. 2023. Global warming intensity of biofuel derived from switchgrass grown on marginal land in Michigan. GCB Bioenergy 15:319-331. [PDF]

Lei, C., J. Chen, and G. P. Robertson. 2023. Climate cooling benefits of cellulosic bioenergy crops from elevated albedo. GCB Bioenergy doi:10.1111/gcbb.13098 [PDF]

Liang, K., X. Zhang, X.-Z. Liang, V. L. Jin, G. Birru, R. Schmer Marty, G. P. Robertson, G. W. McCarty, and G. E. Moglen. 2023. Simulating agroecosystem soil inorganic nitrogen dynamics under long-term management with an improved SWAT-C model. Science of the Total Environment 879:162906. [PDF]

Lucas, M., J. Gil, G. P. Robertson, N. E. Ostrom, and A. Kravchenko. 2023. Changes in soil pore structure generated by the root systems of maize, sorghum and switchgrass affect in situ N2O emissions and bacterial denitrification. Biology and Fertility of Soils doi:10.1007/s00374-023-01761-1 [PDF]

Perry, S., G. Falvo, S. Mosier, and G. P. Robertson. 2023. Long-term changes in soil carbon and nitrogen fractions in switchgrass, native grasses, and no-till corn bioenergy production systems. Soil Science Society of America Journal  doi:10.1002/saj2.20575 [PDF]

Pett-Ridge, J., H. Z. Ammar, A. Aui, M. Ashton, S. E. Baker, B. Basso, M. A. Bradford, A. P. Bump, I. Busch, E. R. Calzado, J. W. Chirigotis, N. Clauser, S. Crotty, N. Dahl, T. Dai, M. Ducey, J. Dumortier, N. C. Ellebracht, R. G. Egui, A. Fowler, K. Georgiou, D. Giannopoulos, H. Goldstein, T. Harris, D. Hayes, C. Hellwinckel, A. Ho, M. Hong, S. Hovorka, E. Hunter-Sellars, W. Kirkendall, S. Kuebbing, M. Langholtz, M. Layer, I. Lee, R. Lewis, W. Li, W. Liu, J. T. Lozano, A. Lunstrum, A. C. Mayer, K. K. Mayfield, W. Mcneil, P. Nico, A. O’rourke, S. H. Pang, K. Paustian, G. Peridas, H. Pilorge, M. Pisciotta, L. Price, P. Psarras, G. P. Robertson, W. J. Sagues, D. L. Sanchez, C. D. Scown, B. M. Schmidt, E. W. Slessarev, N. Sokol, A. J. Stanley, A. Swan, C. Toureene, A. A. Wong, M. M. Wright, Y. Yao, B. Zhang, Y. Zhang, and R. D. Aines. 2023. Roads to Removal: Options for Carbon Dioxide Removal in the United States. Lawrence Livermore National Laboratory. https://roads2removal.org/  [PDF]

Robertson, G. P. 2023. Denitrification and the challenge of scaling microsite knowledge to the globe. mLife 2:229-238. [PDF]

Tejera-Nieves, M., M. Abraha, J. Chen, S. K. Hamilton, G. P. Robertson, and B. J. Walker. 2023. Seasonal decline in leaf photosynthesis in perennial switchgrass explained by sink limitations and water deficit. Frontiers in Plant Science 13:1023571. [PDF]


Menefee, D., R. L. Scott, M. Abraha, J. G. Alfieri, J. Baker, D. M. Browning, J. Chen, J. Gonetg, J. M. F. Johnson, G. R. Miller, R. Nifong, G. P. Robertson, E. S. Ressel, N. Saliendra, A. P. Schreiner-Mcgraw, A. E. Suyker, P. Wagle, C. Wente, P. M. White, and D. Smith. 2022. Unraveling the effects of management and climate on carbon fluxes of U.S. croplands using the USDA Long-Term Agroecosystem (LTAR) network. Agricultural and Forest Meterology 326:109154. [PDF]

Pan, D., I. Gelfand, L. Tao, M. Abraha, K. Sun, X. Guo, J. Chen, G. P. Robertson, and M. A. Zondlo. 2022. A new open-path eddy covariance method for N2O and other trace gases that minimizes temperature corrections. Global Change Biology 28:1446-1457. [PDF]

Robertson, G. P., S. K. Hamilton, K. Paustian, and P. Smith. 2022. Land-based climate solutions for the United States. Global Change Biology 28:4912-4919. [PDF]

Sciusco, P., J. Chen, V. Giannico, M. Abraha, C. Lei, G. Shirkey, J. Yuan, and G. P. Robertson. 2022. Albedo-induced global warming impact at multiple temporal scales within an upper Midwest USA watershed. Land 11:283. [PDF]

Vitousek, P. M., X. Chen, Z. Cui, X. Liu, P. A. Matson, I. Ortiz-Monasterio, G. P. Robertson, and F. Zhang. 2022. Climate-change-induced temporal variation in precipitation increases nitrogen losses from intensive cropping systems: Analysis with a toy model. Frontiers of Agricultural Science and Engineering 9:457-464. [PDF]


Abraha, M., J. Chen, S. K. Hamilton, P. Sciusco, C. Lei, G. Shirkey, J. Yuan, and G. P. Robertson. 2021. Albedo-induced global warming impact of Conservation Reserve Program grasslands converted to annual and perennial bioenergy crops. Environmental Research Letters 16:084059. [PDF]

Aoda, M. I., A. J. M. Smucker, S. S. Majeed, H. A. Mohammed, F. H. Al-Sahaf, and G. P. Robertson. 2021. Novel root zone soil water retention improves production with half the water in arid sands. Agronomy Journal 13:2398-2406. [PDF]

Belanger, M., C. Vizza, G. P. Robertson, and S. S. Roley. 2021. Quantifying and correcting for pre-assay CO2 loss in short-term carbon mineralization assays. SOIL 7:47-52. [PDF]

Grace, P. and G. P. Robertson. 2021. Soil carbon sequestration potential and the identification of hotspots in the Eastern Corn Belt of the United States. Soil Science Society of America Journal 85:1410-1424. [PDF]

Hussain, M. Z., S. K. Hamilton, G. P. Robertson, and B. Basso. 2021. Phosphorus availability and leaching losses in annual and perennial cropping systems in an upper US Midwest landscape. Scientific Reports 11:20367. [PDF]

Kravchenko, A. N., H. Zheng, Y. Kuzyakov, G. P. Robertson, and A. K. Guber. 2021. Belowground interplant carbon transfer promotes soil carbon gains in diverse plant communities. Soil Biology and Biochemistry 159:108297. [PDF]

Liang, D. and G. P. Robertson. 2021. Nitrification is a minor source of nitrous oxide (N2O) in an agricultural landscape and declines with increasing management intensity. Global Change Biology 27:5599-5613. [PDF]

Lowry, C., G. P. Robertson, and D. C. Brainard. 2021. Strip-tillage decreases soil nitrogen availability and increases the potential for N losses in a cover cropped organic system. Agriculture, Ecosystems & Environment 319:107524. [PDF]

Mosier, S., S. C. Córdova, and G. P. Robertson. 2021. Restoring soil fertility on degraded lands to meet food, fuel, and climate security needs via perennialization. Frontiers in Sustainable Food Systems 5:706142. [PDF]

O’Neill, B., C. D. Sprunger, and G. P. Robertson. 2021. Do soil health tests match farmer experience? Assessing biological, physical, and chemical indicators in the upper Midwestern United States. Soil Science Society of America Journal 85:903-918. [PDF]

Roley, S. S., T. C. Ulbrich, and G. P. Robertson. 2020. Nitrogen fixation and resorption efficiency differences among twelve upland and lowland switchgrass cultivars. Phytobiomes 5:97-107. [PDF]

Saha, D., B. Basso, and G. P. Robertson. 2021. Machine learning improves predictions of agricultural nitrous oxide (N2O) emissions from intensively managed cropping systems. Environmental Research Letters 16:024004. [PDF]

Spawn-Lee, S. A., T. J. Lark, H. K. Gibbs, R. A. Houghton, C. J. Kucharick, C. Malins, R. E. O. Pelton, and G. P. Robertson. 2021. Comment on ‘Carbon intensity of corn ethanol in the United States: state of the science’. Environmental Research Letters 16:118001. [PDF]

Udvardi, M., F. E. Below, M. J. Castellano, A. J. Eagle, K. E. Giller, J. K. Ladha, X. Liu, T. M. Maaz, B. Nova-Franco, N. Raghuram, G. P. Robertson, S. Roy, M. Saha, S. Schmidt, M. Tegeder, L. M. York, and J. W. Peters. 2021. A research road map for responsible use of agricultural nitrogen. Frontiers in Sustainable Food Systems 5:660155. [PDF]