Plant-soil Feedbacks in Rangelands and Pastures
Date
2021-03-16
Authors
Bennett, Jonathon
Awodele, Stephen
Kuper-Psenicnik, Aisa
Lundell, Seth
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Abstract
Every plant interacts with a diverse array of soil microbes, with some of these interactions being positive (e.g. mycorrhizas or rhizobacteria) and others negative (e.g. pathogens). Over a plant's lifespan, these organisms accumulate and can have strong effects on plant performance (i.e., plant-soil feedbacks), with the net effect dependent on the relative strengths of the positive and negative interactions. Recent work in my group explores whether manipulating the plant composition of pastures and rangelands may allow us to enhance the positive aspects of these plant-soil feedbacks. In a 20-year-old mixture diversity trial in Minnesota, we found that seeding diverse mixtures can create soils that increase plant growth by increasing beneficial microbes and reducing root damage from pathogens and nematodes. In a separate experiment using soils from native rangelands, however, plant diversity effects on plant-soil feedbacks differed among species. When testing the response of different forages to soils collected from alfalfa monocultures and mixtures, plant growth responses were highly dependent on the forage species and alfalfa variety seeded. Other experiments in our group suggest that this variation among alfalfa varieties in their responses to different soils may be partially attributable to differences in their interactions with mycorrhizal fungi, as these interactions also differ among alfalfa varieties with strong effects on plant growth. Combined, these results highlight the effects of mixture diversity on soil microbial communities. The strong variation among plant species and varieties in their responses to soil microbes also suggests that the effects of soil microbes on forage growth will depend on species and variety selection. Although the picture may currently be incomplete, by better understanding these differences we can improve pasture management through more effective mixture design and choosing the right seed for pasture rejuvenation. Link to Video Presentation: https://youtu.be/xHh2rCFgNuM
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Pasture, Rangeland, Plant-Soil Feedback
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Soils and Crops Workshop