Sarah Collier

Collier CAP prof smallPostdoctoral Fellow

PhD – Plant Breeding, Cornell University, 2011

BSc – Botany, University of Washington, 2004

Curriculum vitae


Sarah is an NSF Science, Engineering, and Education for Sustainability (SEES) Postdoctoral Fellow working jointly with the Jahn Research Group and the Ruark Nutrient Cycling and Agroecosystems Laboratory.  Her work involves research, education, and outreach related to agricultural sustainability, food system complexity, and decision-making in landscape management. Much of Sarah’s work focuses on soil quality in crop – livestock systems, and fits under the overarching hypothesis that management practices geared towards building soil quality have the potential to improve the overall resilience of agricultural systems. Sarah is a part of the Sustainable Dairy Coordinated Agricultural Project, and is also involved in international efforts to promote research integration and data harmonization, such as the Global Farm Platform for sustainable ruminant production.


IMG_4404Cropping system resilience to water stress. As many regions of the world face increasing threat of water stress, there is a need for intensified focus on soil water holding dynamics, and the ways in which management practices affect agroecosystem performance under stress. Working at the long-term Wisconsin Integrated Cropping System Trials, we are utilizing both in-field and laboratory analysis to compare the effect of rotations of varying complexity on soil water dynamics and system performance under stress. Photo: undergraduate research assistants collect soil cores for laboratory analysis.

IMG_2679Greenhouse gas emissions in dairy forage production. Nitrous oxide emitted from cropland constitutes a significant component of the agricultural sector’s overall greenhouse gas footprint. In order to accurately evaluate mitigation strategies, predict impacts, and model system behavior under future climate scenarios, it is essential to have access to flux measurements collected under regionally relevant conditions of soil, weather, and management strategies. We are measuring nitrous oxide flux from a typical dairy forage rotation consisting of one year of corn followed by three years of alfalfa, which receives fertilizer in the form of liquid dairy manure. This data will be used to calibrate models for use in footprinting and benchmarking efforts and in predicting future productivity, impact, and resilience of dairy-based systems. Photo: a greenhouse gas chamber deployed between rows of corn.

IMG_3065 - Version 2Long-term effect of fertilizer rate on soil carbon and nitrogen. Increased interest in intensive corn production due to its value as a biofuel feedstock raises questions about the sustainability of yield and maintenance of soil quality in such systems – particularly continuous corn receiving mineral N fertilizer. In a long-term continuous corn trial, we are examining the impact of variable rates of fertilizer on soil C and N as well as other indicators of soil quality and overall system stability. Photo: undergraduate research assistants help with field elevation mapping.


Collier, S.M., Ruark, M.D., Oates, L.G., Jokela, W.E., and Dell, C.J. 2014. Measurement of greenhouse gas flux from agricultural soils using static chambers. Journal of Visualized Experiments. E52110.

Collier, S.M., Ruark, M.D., Bland, W., and McNamee, E. Building resilience: effect of long-term crop rotation on soil water characteristics. ASA, CSSA, & SSSA International Annual Meeting, Long Beach, CA, November 2-5 2014.

Collier, S.M., Kraus, G.M., and Jahn, M.M. Energizing high school science education through a focus on food systems. Ecological Society of America Annual Meeting, Sacramento, CA, August 10-15, 2014

Jahn, M. and Collier, S.M. Location, people, and policy: soils and ecosystem services (Sustainable provisioning and the agricultural landscape). Invited talk, SSSA Special Session – Soil Science Research in the 21st Century: Opportunities Beyond Disciplinary Boundaries. ASA, CSSA, & SSSA International Annual Meeting, Tampa, FL, November 3-6, 2013.

Collier, S.M., Ruark, M.D., and Naber, M.R. Fifty years of nitrogen fertilization: effects on soil carbon and nitrogen. ASA, CSSA, & SSSA International Annual Meetings, Tampa, FL, November 3-6, 2013.

Plant genetic resources: an essential foundation for U.S. and global provisioning, economy, sustainability and security” – a position statement of the Crop Science Society of America, October 2013. (M. Jahn and S. Collier, writing team members)

Collier, S.M., Hamel, L-P., and Moffett, P. 2011. Cell death mediated by the N-terminal domains of a unique and highly conserved class of NB-LRR protein. Molecular Plant-Microbe Interactions 24: 918-931.

Brummer, E.C., Barber, W.T., Collier, S.M., Cox, T.M., Johnson, R., Murray, S.C., Olsen, R.T., Pratt, R., and Thro, A.M. 2011. Plant breeding for harmony between agriculture and the environment. Frontiers in Ecology and the Environment 9: 561-568.

Collier, S.M. and Moffett, P. 2009. NB-LRRs work a “bait and switch” on pathogens. Trends in Plant Science 14: 521-529.

Mazourek, M., E.T. Cirulli, S. M. Collier, L. G. Landry, B-C. Kang, E. A. Quirin, J. M. Bradeen, P. Moffett and M. Jahn. 2009. The fractionated orthology of Bs2 and Rx/Gpa2 supports shared synteny of disease resistance in the Solanaceae. Genetics 182:1351-1364.