Graduate Researcher Cornell University Trumansburg, New York
Body of Abstract: Plants interact with soil microbiomes in nuanced ways, which can provide benefits such as enhanced resistance to varied stressors. It is widely recognized that soil microbiomes are influenced by many variables, such as plant cultivation practices, biotic/abiotic stresses, and the legacies of these factors across time. How these variables interact, differ between systems, and affect emergent functions aren’t understood. To investigate this, multi-year/location field trials were conducted in New York. Four cash crops (dry bean, soybean, sweet corn, and sunflower) were grown in field plots treated with different cover crop regimes (hairy vetch, cereal rye, hairy vetch x cereal rye, or canola) or in tilled control plots. Each year crop tissue and soil were collected from the field for laboratory experiments. Tissue was used to measure phytohormones that are indicative of biotic and abiotic stress responses: jasmonic acid (JA), salicylic acid (SA), and abscisic acid (ABA). The impact of cover crop legacies on cash crop phytohormones varied across crop species; however, there were significant impacts of cover crops within individual cash crop species. Importantly, hairy vetch and cereal rye conditioning reduced ABA content in soybean and dry bean, cereal rye decreased SA content in dry bean, and hairy vetch and cereal rye decreased SA content in sunflower. To clarify the soil microbiome’s role in our field findings, we grew dry bean in the laboratory with microbiomes extracted from each field treatment. Consistent with the field data, dry bean grown with cereal rye and hairy vetch treatments displayed significantly lower ABA levels. These results suggest that cover crops can shape soil microbiomes for specific functions––however, how distinct crop species leverage these functions varies. Questions remain regarding the specific aspects of the microbiome that shape these contrasts, and the impact of environmental conditions on microbiome-derived functions.