Dissertation
SOIL QUALITY AND MANAGEMENT ALTERNATIVES IN RED RASPBERRY (RUBUS IDAEUS L.) IN THE PACIFIC NORTHWEST
Doctor of Philosophy (PhD), Washington State University
01/2017
Handle:
https://hdl.handle.net/2376/108368
Abstract
Washington leads the nation in floricane red raspberry (Rubus idaeus L.) production. A typical red raspberry production system consists of preplant soil fumigation followed by herbicide spraying and repeated alleyway cultivation for weed control once the crop is established. These practices are detrimental to soil quality, causing harm to beneficial soil microorganisms, as well as increased soil erosion, compaction, and decreased water infiltration. Alleyway cover crops are a potential alternative, but growers are concerned about the risk of resource competition with the raspberry crop as well as increasing population densities of Pratylenchus penetrans. Raspberry plants can experience severe pressure from the plant-parasitic nematode, Pratylenchus penetrans, which has been shown to contribute to reduced raspberry plant vigor, yield, and economic returns. A two-year field study was conducted in an established, commercial red raspberry field in Whatcom County. Nine cover crops were seeded in the alleyways between raspberry beds and effects on physical, chemical, and biological soil quality parameters were evaluated, including: bulk density, compaction, nutrient content/availability, P. penetrans densities their roots and surrounding soil, and overall microbial community structure. Raspberry yield and fruit quality were also evaluated to assess plant productivity. Cultivated, bare soil served as the control. All ground covers selected for the field study were also evaluated for P. penetrans host suitability in greenhouse assays. Raspberry grown adjacent to cultivated, bare soil alleyways did not fare better than raspberry grown adjacent to alleyways with cover crop under any measured parameter. Cover crops grown in the alleyways did not increase P. penetrans population densities in raspberry roots or surrounding soil. At the last sampling date, bulk density was lowest in the alleyway with a perennial grass mix. There was no significant difference in fruit yield or total soluble solids among treatments. All of the cover crops were hosts for P. penetrans, but differed in their suitability; none were as good of hosts as raspberry in the field. The potential benefits of cover crops for soil quality outweigh the perceived risks to the raspberry production system.
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Details
- Title
- SOIL QUALITY AND MANAGEMENT ALTERNATIVES IN RED RASPBERRY (RUBUS IDAEUS L.) IN THE PACIFIC NORTHWEST
- Creators
- Rachel Rudolph
- Contributors
- Lisa DeVetter (Advisor)Inga Zasada (Advisor)Mark Mazzola (Committee Member)Preston Andrews (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Horticulture
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 169
- Identifiers
- 99900581426401842
- Language
- English
- Resource Type
- Dissertation