Belowground interactions at multiple scales in a grapevine-groundcover agroecosystem
Restricted (Penn State Only)
- Author:
- Fleishman, Suzanne
- Graduate Program:
- Ecology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 02, 2022
- Committee Members:
- Paul Esker, Outside Unit & Field Member
David Eissenstat, Co-Chair & Dissertation Advisor
Terrence Bell, Major Field Member
Michela Centinari, Co-Chair & Dissertation Advisor
Jason Kaye, Program Head/Chair - Keywords:
- Groundcover
vineyard
agroecology
rootstock
microbiome
rhizosphere
deep roots - Abstract:
- The science of agroecology is central to designing management practices that will continue food production without disrupting ecological processes that promote agroecosystem functions. Fruit and nut cropping systems can implement agroecological practices by planting groundcovers (also referred to as cover crops) in between crop rows or across the full vineyard or orchard floor. Poor understanding of how groundcovers shift crop root-associated microorganisms, soil properties, and grapevine growth limits full realization of the practice. This dissertation explored the impacts of a full-floor grass groundcover in a high-soil resource vineyard across multiple scales of examination and with a particular focus on soil depth. The dissertation begins with three chapters focused at the scale of root-microbial interactions and expands in the following two chapters to examine vineyard soils and whole plant growth. Chapters 2 and 3 documented the potential for improvements in our understanding of root-microbial interactions with functionally and spatially explicit approaches to examining rhizospheres. Chapter 4 then applied these considerations to the grapevine-groundcover agroecosystem. We found that groundcovers increase grapevine rhizosphere bacterial diversity and shift bacterial composition in a similar manner across depth but alter rhizosphere fungi in a depth-dependent manner. Chapter 5 documented that due to increases in total root mass at shallow depths, groundcover practices can substantially increase in soil total carbon up to 40 cm. Lastly, chapter six found that over five years the groundcover practice in combination with a devigorating rootstock can impart substantial agroecosystem services to vineyards. In summary, we found that over five years and in a temperate vineyard in Pennsylvania, groundcover management practices substantially influenced root distributions, soil resource availability, soil carbon, and rhizosphere bacteria and fungi, often most pronounced at shallow depths. These studies demonstrate the importance of examining agroecological practices across multiple scales and root responses across depth. Understanding of the grapevine-groundcover agroecosystem can be further expanded with methodological developments that facilitate root and rhizosphere research.