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Lori A Hoagland

Horticulture and Landscape Architecture 

  • Associate Professor of Horticulture
Horticulture Room 314

Area of Expertise: Microbial Ecology of Horticultural Systems


  • PhD, Soil Microbiology and Biochemistry, Washington State University
  • MS, Agroecology, University of Nebraska-Lincoln
  • BS, Environmental Science, University of Nebraska-Lincoln


Feeding the world's growing population while dealing with soil and water degradation, rapidly evolving pests and increasing climate instability will require innovative solutions. To address these challenges my lab studies soil microbial ecology and plant-microbial relationships. The soil microbial community regulates many key agroecosystems services including soil nutrient and heavy metal cycling and keeping pest populations in check. Moreover, some soil microbes can form intimate associations with plants helping them acquire nutrients, withstand biotic and abiotic stress, and improve the yield, quality and safety of produce. Development of new genomic tools has greatly expanded awareness of the abundance and diversity of these soil and plant microbiomes, but understanding of their function and how to manage them to improve agroecosystem performance is in its infancy. The long-term goal of my research program is to address these knowledge gaps by elucidating how key soil, microbe and plant host factors interact to regulate the assembly and activity of microbiomes in specialty crop product systems, while identifying practical approaches to manage them in ways that will help growers achieve the following goals:

Improve nitrogen-use efficiency: Less than 50% of nitrogen (N) fertilizer applied is generally recovered by crop plants. The remaining fertilizer is subject to loss via leaching and evolution of nitrous oxide, a potent greenhouse gas, resulting in environmental degradation and lost profits for growers. To help overcome this challenge we are 1) determining how the composition of fertility amendments interact with site-specific soil, environmental and crop management practices to alter the composition, abundance and activity of microbial taxa that regulate the soil N cycle, and 2) identifying vegetable genotypes that are more efficient at scavenging soil N and investigating potential mechanisms regulating this activity.

Biologically control pathogens: Keeping up with newly introduced pathogens, existing pathogens that evolve to overcome resistance conferred by plant genetics and commonly used pesticides, and systems (ie. high tunnels) that limit crop rotation is difficult. To help overcome these challenges we are 1) determining how soil management practices, amendments and vegetable genotypes interact to modify pathogen populations and the abundance and activity of microbes with plant growth promoting and biocontrol activity, and 2) identifying genotypes that are more responsive to induced systemic resistance and investigating the mechanisms regulating these beneficial plant-microbial relationships.

Mitigate heavy metal stress: Contamination of soil with heavy metals negatively affects the health and productivity of crops. Moreover, accumulation of heavy metals in edible plant tissues negatively affects human health and is a liability for growers. To help overcome this challenge we are 1) identifying soil amendments and root endophytes that can help plants tolerate heavy metal stress and reduce bioaccumulation in edible plant tissues, 2) identifying vegetable genotypes that vary in their potential to accumulate heavy metals and investigating potential mechanisms, and 3) identifying imaging fingerprints that can be used to detect heavy metal stress in plants.

Plant improved plant varieties: Someday it may be possible to improve the productivity, quality and safety of vegetable crops by specifically selecting for beneficial plant-microbial relationships in plant breeding programs. In the meantime we are testing the hypothesis that plant breeders can indirectly select for these relationships by conducting breeding programs under low-input organic farming systems. At the same time we are helping to develop new varieties that are optimally adapted to these systems and have improved agronomic and end-use quality characteristics. Details for two of these on-going projects can be found at the following websites.

Courses Taught:

  • HORT 20100 – Plant Propagation (2010-2014)
  • SFS/HORT 31200 – Introduction to Urban Agriculture (2015-present)
  • SFS/HORT 49000 – Agroecosystem Analysis (new study abroad course in Colombia coming summer 2019)
  • HORT 52500 – The Plant Microbiome (formerly HORT 49000 Rhizosphere Ecology) (2014-present)

Awards & Honors

(2015) Millionaire's Club Award. Purdue University.

(2011) Millionaires Club Award. Purdue University.

(2015) Acorn Seed of Excellence Award. Purdue University.

(2011) International Travel Grant Award. Agriculture Research Program, Purdue University.

(2011) Acorn Seed of Excellence Award. Purdue University.

Selected Publications

Hoagland, L., Ximenses, E., Ku, S., & Ladisch, M. (2018). Foodborne pathogens in horticultural production systems: ecology and mitigation. Scientia Horticulturae, 236, 192-206.

Colla, G., Hoagland, L., Ruzzi, M., Cardarelli, M., Bonini, P., Canaguier, R., & Rouphael, Y. (2017). Biostimulant Action of Protein Hydrolysates: Unraveling Their Effects on Plant Physiology and Microbiome. Frontiers in Plant Science, 22, 1-14. doi:doi.org/10.3389/fpls.2017.02202

Ximenes, E. A., Hoagland, L. A., Ku, S., & Ladisch, M. R. (2017). Human pathogens in biofilms: formation, physiology and detection. Biotechnology and Bioengineering. doi:10.1002/bit.26247

Simon, P., Navazio, J., Colley, M., Hoagland, L. A., Roberts, P., DuToit, L., . . . McCluskey, C. (2017). The CIOA Project: Location, cropping system, and genetic background influence carrot performance including top height and flavor. Acta Horticulturacea. doi:https://doi.org/10.17660/ActaHortic.2017.1153.1

Reeve, J., Hoagland, L. A., Villalba, J., Carr, P., Attucha, A., Cambardella, C., . . . Davis (2016). Organic farming, soil health, and food quality: Considering possible linkages. Advances in Agronomy, 137, 1-49.

Rudisill, M., Turco, R. F., & Hoagland, L. A. (2016). Rhizosphere effects and fertility management influence nitrification and ammonia oxidizers in intensively managed vegetable production systems. Applied Soil Ecology, 99, 70-77.

Shoaf, N., Egel, D. S., & Hoagland, L. A. (2016). Suppression of Phytophthora blight in sweet pepper depends on biochar amendment and soil type. Hortscience, 51(5), 518-524.

Hallett, S. G., Hoagland, L. A., & Toner, E. (2016). Urban agriculture: environmental, economic and social perspectives. Horticulture Reviews, 44, 65-109.

Hoagland, L. A. (2015). Breeding for beneficial plant-microbial relationships: how do we get there? Eucarpia Workshop On Implementing Plant-Microbe interaction in Plant Breeding,, 23-24.

Rudisill, M., Turco, R. F., & Hoagland, L. A. (2015). Sustaining soil quality in intensively managed high tunnel vegetable production systems; a role for green manures and chicken litter. Hortscience, 50(3), 461-468.

Horticulture & Landscape Architecture, 625 Agriculture Mall Drive, West Lafayette, IN 47907-2010 USA, (765) 494-1300

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