Harnessing Variation in Vetch and Rhizobia Populations to Optimize Nitrogen Fixation
Project Director
Laurie Drinkwater
Year Funded
2018
Award Number
2018-51106-28778
Funded Institution
Cornell University
Grant Program
ORG (Organic Transitions)
USDA NIFA Report (alternate)
Project Overview
Lab, greenhouse, and field experiments were conducted to determine whether plant and/or Rhizobia genetics could be selected to enhance symbiotic nitrogen fixation (SNF) in hairy vetch, especially when grown as a winter cover crop in colder climates. Thirty cold-hardy vetch lines were grown to determine how SNF and arbuscular mycorrhizal fungal (AMF) colonization vary with crop genotype. Other experiments were conducted to determine the effect of crop genotype, rhizobia strain, soil N levels, management history, climate, and genetic X environmental interactions on plant vigor, cold hardiness, and percent of N derived from SNF.
Farmer Takeaways
(1) The primary target audience of this research was plant breeders who will utilize findings to speed development of legume cultivars with improved nitrogen fixation.
(2) Proper seed inoculation is important for effective SNF.
(3) ‘AU Merit’ hairy vetch available through Smith Seed Services is best suited to the Southern region, where it attains superior biomass, matures early, and maintains greater SNF during cool weather (50-60°F) than other vetch strains.
(4) Legumes with active N fixing nodules (pink interior) may have greater freeze tolerance than the same species with inactive (white interior) or no nodules.
Project Outputs
Rhizobia Inoculation for Organic Farming Systems | University of Minnesota Extension
Webinar: Using Legumes to Supply Crop Nitrogen While Also Reaping Benefits for Soil Health | NRCS
Muller, K. E., J. Guinness, M. Hecking, and L. E. Drinkwater. 2021. Estimating agronomically relevant symbiotic N fixation in green manure breeding programs. Crop Science 61(5): 3314-3330.
Schaedel M, Fudge R, Grossman J. Biological Nitrogen Fixation within Agroecosystems and Plant Roots. Biological Approaches to Regenerative Soil Systems, 2nd Edition, edited by Norman Uphoff and Janet Thies, published by CRC Press. Approaches to Regenerative and Resilient Soil Systems, CRC Press, 2024, pp. 129 – 139.