Genotypic Variability in Microbially-Mediated Plant Soil Feedback of Alfalfa in Perennial Agroecosystems
Date
2021-03-16
Authors
Awodele, Stephen
Bennett, Jonathon
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Conference Presentation
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Soil conditioning in agroecosystem occurs when weed and crop species influence soil micro-organisms, resulting in plant-soil feedback (PSF). Positive PSFs result from beneficial plant-microbe relationships that facilitate plant growth, whereas negative PSFs arise from the accumulation of pathogenic soil microbes and play important role in soil sickness. This problem is amplified, especially in the perennial system, due to the accumulation of species-specific soil pathogens which also limit the growth of conspecific seedlings. Genotypic variation in host resistance to pathogens and enhanced mutualisms have been shown to influence PSF, and manipulation of these interactions is an emerging strategy to overcome soil sickness in agricultural systems, yet the effect of conspecific feedback on seeded perennial pastures is poorly understood. To examine genotypic variability in microbially-mediated PSF, four varieties of alfalfa (Medicago sativa) were grown in soils previously conditioned by alfalfa in the field in either monoculture or mixtures and of varying stand ages (1 to 6 years old). To explain genotype by environment variability in PSF for alfalfa, we also examined other biotic and abiotic components. Mixtures reduced the impact of negative PSF by approximately 3 folds relative to monoculture, whereas temporal variability had no effect on intraspecific PSF. Alfalfa genotype strongly affects microbially-mediated PSF. Alfalfa varieties experienced negative PSF at a varying degree in monoculture, while only one variety had a positive PSF in mixture. Our data suggest that PSF caused a genotype-dependent alteration to fiber quality in monoculture and that soil texture may be an important predictor of PSF in mixtures. Collectively, these results demonstrate the role that soil microbiomes through aboveground-belowground linkages play in soil health and the importance of genotypic variability in the manipulation of soil microbiomes for sustainable agriculture. Link to Video Presentation: https://youtu.be/DNfYPnOD4nE
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Soil Conditioning, Plant-Soil Feedback, Perennial System
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Soils and Crops Workshop