Dissertation
Impacts of nitrogen fertility, soilborne disease, and socioeconomic factors on diverse small grain production systems of the Pacific Northwest
Doctor of Philosophy (PhD), Washington State University
01/2012
Handle:
https://hdl.handle.net/2376/4295
Abstract
Small grains are grown in rotation with many temperate crops in the Columbia Basin and Puget Sound regions, functioning to improve the profitability of the cash crops. During 2009-10, 45 isolates of Rhizoctonia spp. were collected from Columbia Basin fields in which onions were cultivated in sequence with cereal cover crops. Isolates were characterized as R. solani AGs 2-1, 3, 4, 5, 8, and 9; \\textit{Waitea circinata}; and binucleate Rhizoctonia spp. AGs A, E, and I. At 8-15°C, stunting of onion was caused by isolates of AG 2-1, 3, 4, 8, E, and W. circinata. The most virulent isolates belonged to AG 8, confirming a possible cereal-onion disease bridge, although one isolate each of AG 3 and E were also highly virulent. AG 2-1 and 3 isolates were of moderate virulence. During 2009-10 and 2010-11, the influence of nitrogen (N) rate (0, 85, and 170 kg N/ha) and source (poultry feather meal and sulfur-coated urea) on the agronomic performance, flour quality, and phenolic acid (PA) content of four hard red winter wheat cultivars was assessed in Skagit County. Yields of up to 10.1 Mg/ha were realized, as were grain protein contents of 12 to 14%. High N rates reduced test weights up to 4%, but increased protein content by 1% on average. Micro-SDS volumes averaged 10.6-12.7 cm3/g, values correlated in other studies with desirable loaf characteristics. Seven PAs were identified by HPLC in grain of the 2009-10 cultivars, as were four ferulic acid dehydrodimers (DiFAs). N fertilization was only a significant source of variation for ferulic acid and DiFA concentrations. A mail survey was conducted of past, current, and prospective grain growers in the Puget Sound to assess their marketing strategies, information uses, and challenges. Although current growers rely on the commodity market, many were interested in direct-to-consumer markets. Product segmentation is limited by infrastructure, without which regional markets are difficult to access. Animal feed was the crop use of greatest importance. Compared with current growers, prospective growers were more apt to value university- and Extension-based sources of production information, and to be guided by sustainable agriculture principles.
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Details
- Title
- Impacts of nitrogen fertility, soilborne disease, and socioeconomic factors on diverse small grain production systems of the Pacific Northwest
- Creators
- Lucas Patzek
- Contributors
- Stephen S Jones (Advisor)Lindsey J du Toit (Committee Member)Jessica R Goldberger (Committee Member)Carol A Miles (Committee Member)Timothy C Paulitz (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 306
- Identifiers
- 99900581854701842
- Language
- English
- Resource Type
- Dissertation