In Oregon’s northern Willamette Valley, cabbage maggot (CM), Delia radicum (L.) (Diptera: Anthomyiidae) often renders Brassica root crops unmarketable. Scheduled insecticides are the only current control. Studies were conducted to: 1) describe and characterize spring emergence of CM flies and their seasonal flight activity relative to degree-day (DD) accumulations; 2)...
A method based on fatty acid (FA) analysis is used to profile microbial community structure (MCS). Various extraction protocols are available, which alter the types of FAs extracted from soils. The more time consuming but widely used protocol extracts only FAs from phospholipids (PLFA). This technique is desirable because PLFAs...
Quantitative resistance (QR) to disease is usually more durable than qualitative resistance, but its genetic basis is not well understood. We used the barley/barley stripe rust pathosystem as a model for the characterization of the QR phenotype and associated genomic regions. As an intermediate step in the preparation of near-isogenic...
Small broomrape (Orobanche minor) is an obligate, chlorophyll-lacking parasite that parasitizes red clover (Trifolium pratense) roots. This study was conducted to develop and implement an integrated, biologically based control program for small broomrape by using wheat as a false host to reduce the soil seed bank. The relationship between temperature...
Two native shrub species (Piliostigma reticulatum and Guiera senegalensis) are prominent vegetation components in farmers’ fields in Senegal. However, their role in nutrient cycling and ecosystem function has largely been overlooked. A study including both laboratory and field experiments was conducted to evaluate potential biophysical interactions of the two shrub...
Weeping alkaligrass (Puccinellia distans) and Nuttall’s alkaligrass (Puccinellia
nuttalliana) infest Kentucky bluegrass seed fields of eastern Oregon. Weeping
alkaligrass is an introduced species from Eurasia, whereas Nuttall’s alkaligrass is
native to semi arid environments of western North America. These species are often
referred to collectively as ‘alkaligrass’; however, for farmers...
The objectives of this thesis were to examine the links between soil microbial community composition and function using the nitrogen (N) cycle as a model for these interactions and to assess the impact of environmental factors such as microclimate, vegetation type, and nutrient availability on microbial diversity and N transformations...
A suspected glyphosate-resistant Italian ryegrass (Lolium multiflorum) (OR) population was collected from a filbert (Corylus avellana L.) orchard near Portland, OR. Based on the dose-response experiments conducted in the greenhouse, it was found that the suspected glyphosate-resistant population was approximately fivefold more resistant to glyphosate than the susceptible (S) population....
Piliostigma reticulatum and Guiera senegalensis are two native shrubs that
coexist with row crops in parkland systems of the Sahel of Africa. Although
permanently green all year around in soil depleted in nutrients and dry for a nine-month
period, these shrubs have been largely overlooked. Conventional management of these
shrubs...
Conventional soil maps represent a valuable source of information about soil
characteristics, however they are subjective, very expensive, and time-consuming to
prepare. Also, they do not include explicit information about the conceptual mental
model used in developing them nor information about their accuracy, in addition to the
error associated with...
There is growing concern among producers regarding the sustainability of current dryland winter wheat cropping practices. This study looks at the economic viability of three wheat rotations currently being studied at the Columbia Basin Research Center in Pendleton, Oregon, including W IF and two alternative rotations, W/B/F and C/W/F. The...
Hop downy mildew is a devastating disease affecting hop requiring expensive
fungicide applications throughout the growing season. Plant resistance is highly
desirable and theorized as being decidedly quantitative with dominance and epistasis
involved in resistance. An association mapping approach using a mixed-model was
used to identify AFLP markers associated with...
As part of a participatory research project, where farmers and Oregon State University researchers collaborated, aspects of potato (Solanum tuberosum L.) growing systems were studied. It was determined through conversations with the farmers that quantification of certain growth parameters of potato was lacking, including dry matter accumulation, crop nitrogen (N)...
Field studies were conducted in 1998 and 1999, to evaluate glyphosate and glufosinate for control of redroot pigweed, common lambsquarters, hairy nightshade, and barnyardgrass in herbicide-resistant sugarbeets. Treatments that included two or three applications of glyphosate, regardless of rate, or glyphosate applied once in combination with BAS 656 07 H...
The objective of this study was to examine the variation among ammonia-oxidizing and denitrifying communities in soils of a natural Fennoscandian boreal forest and of a forest with a long history of fertilization with different levels of nitrogen (N), and to examine whether there are any changes in the microbial...
Glutenin protein molecules can form a large "macropolymer" which forms the elastic component of the gluten complex in wheat flour doughs. Little work has been done to investigate relationships between glutenin macropolymer (GMP) and noodle processing. GMP was isolated from flour of 4 wheat varieties; 3 hard- and 1 soft-grained...
This research was undertaken to provide barley growers, processors, and consumers with quality food barley. Because all currently available varieties of food barley are of spring growth habit, the first phase of the research involved agronomic assessment of these varieties under Oregon conditions. Because winter barley usually yields more than...
The objectives of this thesis were to evaluate the responses of soil microbial communities to physical and chemical disturbances, and associate these responses with soil functional stability and changes in soil quality. The first study consisted of application of heat shocks (HS) to soils with contrasting land use history to...
Soils are a globally significant carbon (C) pool and have the potential to respond to elevated CO2 and environmental changes through positive feedback cycles that enhance the turnover of soil organic matter (SOM). Understanding the mechanisms governing the turnover of SOM is particularly important for modeling the fate of C...
Predictive Soil Mapping (PSM) has recently become an attractive method for soil scientists wishing to develop a more objective and efficient approach to mapping soils. Due to the potential PSM has for reducing the effort to produce soil maps, as well as its ability to improve the classification accuracy of...
Soil surveys provide essential information for making land use and management decisions on publicly-owned lands in the semi-arid Great Basin. Soil maps produced with conventional mapping techniques are time-consuming, costly, and do not explicitly document the soil scientist's mental soil-landscape model. Predictive soils mapping using decision tree analysis (DTA) can...
Many agricultural sustainability issues are related to biological processes which are central to the ecological function of soils. Soil physical properties are the architecture in which these processes are carried out. Cover crops hold promise as one of the techniques which can ameliorate poor soil structure and improve bulk density...
Upper Klamath Lake in south central Oregon annually experiences intense
blooms of cyanobacteria, primarily Aphanizomenon flos-aquae. Domination of the
lake phytoplankton community by this single species regularly results in drastic
changes to water quality. Photosynthetic activity of such extensive populations can
result in pH over 10. Blooms typically expire in...
Ectomycorrhizal (ECM) fungi of the genera Piloderma and Ramaria form dense hyphal mats in the organic and upper mineral soil layers, respectively, in coniferous forest floors of the Pacific Northwest. Previous studies have determined that fungal mats change the chemical, physical, and biological properties of the soil within. Little information...
Douglas-fir [Pseudotsuga menziesii (Mirbel) Franco] bark (DFB),
sphagnum peat moss, and pumice are the most common substrate components used
in the Oregon nursery industry. Despite the widespread use of these three
components, little information is available on the effect of physical and hydraulic
properties of peat moss and pumice on...
Wetland soils with complex stratigraphy and redoximorphic features occur on the
margin of the Willamette Valley, Oregon. In the Jackson-Frazier wetland, vertisols
show three distinct stratigraphic units that rest uncomformably upon each other and
correspond to the Bashaw series Bss, 2Bt and 3BC horizons. Holocene alluvium
deposited as distal alluvial...
Improving quality of hard white wheat (HW) cultivars in the Pacific Northwest is important to expand exports to Asia. Asian food processors prefer HW grain that can satisfy an array of baking needs, as well as produce superior quality noodle products. Three experimental populations were developed from single cross and...
Published May 2001. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Cephalosporium stripe (Cephalosporium gramineum) is an important disease limiting adoption of conservation tillage practices in the Pacific Northwest. The disease can cause severe loss of grain yield and quality in winter wheat (Triticum aestivum L.). Modified cultural practices can reduce disease incidence, but are not always dependable because of variation...
Compost maturity is an important determinant of end use for composted municipal yard debris, and generally refers to the effect the compost has on plants. The rate of microbial respiration is an indicator of compost stability. The objectives of this research were to: i) determine whether continuous aeration resulted in...
Creeping bentgrass (Agrostis stolonifera L.) is an outcrossing, small- seeded, perennial grass that can establish outside of cultivation and has several compatible relatives. Glyphosate is a nonselective, broad spectrum, herbicide. Transgenic glyphosate-resistant (GR) creeping bentgrass (GRCB) was developed by The Scotts Company and Monsanto, but is still under USDA-APHIS regulated...
It is widely accepted among nursery producers that [Pseudotsuga menziesii (Mirbel) Franco] bark (DFB) is an excellent substrate for container production, hence its widespread use in Oregon and other regions where Douglas fir constitutes a significant portion of the forest products industry. Despite its widespread use, little information is available...
Mayweed chamomile (Anthemis cotula L.) is an annual weed in the Asteraceae family that is commonly found in fields of the Pacific Northwest. Acetolactate synthase (ALS)-inhibiting herbicides are frequently used to control a broad spectrum of weed species including mayweed chamomile. Seeds of four biotypes of mayweed chamomile (KJ, KL1,...
Japanese knotweed is an invasive perennial shrub that dominates riparian
ecosystems. Effective management techniques are currently limited to repeated annual
herbicide applications and there is little science-based information about which control
tactics result in the greatest management success. Restoration of invaded sites to a
functioning riparian plant community is needed...
This thesis explores open questions regarding molecular forms and interactions of natural and synthetic aromatic compounds present in soils and sediments.
Plant biomass-derived black carbon (biochar) generated through incomplete natural and anthropogenic combustion processes is a major source of aromaticity in terrestrial ecosystems. Chapter one represents a detailed account of...