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Testen 2017 Dissertation.pdf (6.94 MB)

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Participatory Research to Improve Soil and Plant Health on Vegetable Farms in Tanzania and Ohio

Testen, Anna Louise
http://orcid.org/0000-0002-6504-9599
http://rave.ohiolink.edu/etdc/view?acc_num=osu1491990803745543

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Plant Pathology.
Plant pathologists must engage with diverse stakeholders and adopt multidisciplinary approaches to develop practical solutions to plant health problems. Two distinct projects were undertaken in this dissertation research, both requiring participatory and multidisciplinary approaches to address research objectives. The overarching objective of the first research project was to develop methods to improve soil and plant health on smallholder tomato farms in the Morogoro Region of Tanzania. Tomato is the main vegetable cash crop grown by smallholder farmers in this region and its production is constrained by plant diseases, limited access to improved tomato varieties, and poor soil health. Disease surveys were conducted in five villages to determine the most prevalent tomato diseases during both the wet and dry production seasons. The most commonly occurring foliar diseases in both seasons were early blight, bacterial spot/speck, viral diseases, and Septoria leaf spot. Ethnophytopathological activities were conducted to gather local disease knowledge in order to improve farmer and researcher communication and elucidate how farmers perceive key diseases. Mother and baby trials were conducted as a participatory crop improvement approach to introduce and evaluate tomato varieties in three villages. Mother trials were conducted in seven environments, and variance partitioning revealed significant genetic effects for all traits measured. Results from baby trials indicated that introduced varieties were locally acceptable to farmers, except for traits related to marketability. A participatory approach was used to improve soil health monitoring by participating farmers. Baseline soil characteristics were gathered from fifty tomato fields in the region, local soil knowledge was elicited from farmers and used to develop a soil health card, and farmers were trained on the use of a low cost soil test kit. Outcome Mapping was used to evaluate participation in mother and baby trials and soil health training. Results suggested that high stakeholder participation levels in mother and baby trials could predict future adoption of introduced cultivars, whereas evaluation of the soil health training indicated few differences in farmer participation and future use of the soil health test kit. The objective of the second research project was to evaluate and adapt anaerobic soil disinfestation (ASD) as a strategy for managing emerging soilborne diseases in high-value Midwestern vegetable production systems. ASD is an environmentally benign method for managing soilborne diseases in which a carbon source is added to soil, the soil is irrigated to saturation, and tarped with plastic mulch for several weeks. ASD studies, both field and growth chamber, were conducted to assess ASD for management of a tomato soilborne disease complex consisting of Verticillium wilt (Verticillium dahliae), corky root rot (Pyrenochaeta lycopersici), black dot root rot (Colletotrichum coccodes), and root knot nematodes (Meloidogyne spp.) and for management of root knot nematodes (Meloidogyne hapla) in lettuce and clubroot (Plasmodiophora brassicae) in mustard greens produced on muck soils. The impacts of ASD on soil bacterial communities were assessed using a high throughput sequencing approach. ASD impacted soilborne diseases and soil microbial communities in a carbon source and soil dependent manner.
Sally Miller (Advisor)
Pierce Paul (Committee Member)
David Francis (Committee Member)
Steven Culman (Committee Member)
334 p.
Plant Pathology
tomato; Solanum lycopersicum; international agriculture; participatory variety selection; anaerobic soil disinfestation; soilborne disease management, ethnophytopathology; soil microbiome; sustainable agriculture; soil health; Tanzania; Outcome Mapping

Recommended Citations

Citations

  • Testen, A. L. (2017). Participatory Research to Improve Soil and Plant Health on Vegetable Farms in Tanzania and Ohio [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1491990803745543

    APA Style (7th edition)

  • Testen, Anna. Participatory Research to Improve Soil and Plant Health on Vegetable Farms in Tanzania and Ohio. 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1491990803745543.

    MLA Style (8th edition)

  • Testen, Anna. "Participatory Research to Improve Soil and Plant Health on Vegetable Farms in Tanzania and Ohio." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1491990803745543

    Chicago Manual of Style (17th edition)

osu1491990803745543
838
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This open access ETD is published by The Ohio State University and OhioLINK.