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Crop Rotation and Nitrogen Fertilization Influence Spatiotemporal Variability in the Maize-Associated Microbiome

Ashley Stengel, University of Nebraska - Lincoln

Abstract

The soil microbiome is increasingly recognized as essential for facilitating ecosystem services. In agroecosystems, the soil microbiome performs important roles in nutrient cycling and soil stabilization that indirectly facilitate crop growth, as well as interact directly shaping crop health and productivity through hostmicrobe interactions. Thus, management efforts to promote plant and soil health must consider the contributions and responses of microbial communities. In particular, the stability of microbiomes across nutrient regimes and spatio-temporal scales is considered important for promoting agroecosystem resiliency and healthy ecosystem functioning. The overarching goal of this dissertation was to characterize patterns in assembly and succession of maize-associated microbiomes. Maize is a globally and regionally important food crop that has been shown to assemble distinct communities based on soil type and soil legacies. As such, this dissertation focused on fungal and bacterial communities associated with maize under different crop rotation and nitrogen fertilization histories. Temporal variability in bacterial and fungal communities was evaluated across the maize growing season from a long-term field site with over 30 years of management history. Management history and maize growth stage cooperatively shaped microbial community structure, with differing responses between fungi and bacteria. The contribution of soil microbial communities to the assembly of maize root-associated communities was tested under greenhouse conditions using soils collected from the long-term field site. In this study, fungal communities of early maize growth stages were more sensitive to management legacies than bacteria, and proximity to maize roots stabilized microbial communities across management histories. Variability of fungal and bacterial communities across spatio-temporal scales is not well characterized, highlighting a key knowledge gap in the study of crop-associated microbiomes. Additionally, findings from long-term management histories are underrepresented posing another key knowledge gap about the ways crop diversity and nitrogen fertilization interact to shape soil and root-associated communities. This work provides important insight into the microbial ecology of maize agroecosystems, highlighting how microbial fractions may play different roles in facilitating crucial ecological processes.

Subject Area

Soil sciences|Microbiology|Agriculture

Recommended Citation

Stengel, Ashley, "Crop Rotation and Nitrogen Fertilization Influence Spatiotemporal Variability in the Maize-Associated Microbiome" (2022). ETD collection for University of Nebraska - Lincoln. AAI30000165.
https://digitalcommons.unl.edu/dissertations/AAI30000165

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