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1
Regan, Richard P. "WATER CONSERVATION IN CONTAINER PRODUCTION NURSERIES—IRRIGATION SCHEDULING". HortScience 31, n.º 6 (octubre de 1996): 917D—917. http://dx.doi.org/10.21273/hortsci.31.6.917d.
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Applying only the amount of water needed by a plant, when it needs it, is a simple concept that can conserve water and reduce runoff. Simple, that is, when managing a single crop that covers an extensive area under several irrigation zones. Container production nurseries grow a large number of plants and each irrigation zone usually has a diverse grouping of taxa in various stages of development. In 1989, a nursery crop project at Oregon State University began to investigate irrigation scheduling for container-grown woody landscape plants. Crop coefficients (kc), used to adjust irrigation to specific production practices and crop characteristics, vary greatly for woody landscape plants. Woody plant kc values range from <1.0 to >5.0 during the production cycle. Plant taxa, growth stage, spacing, and pruning significantly influence kc of container-grown plants. Ilex crenata `Green Island' showed a reduction in water use (40%) immediately after pruning, but had similar kc values 60 days later. Grouping plants with similar kc values under the same irrigation zone is a very difficult task for a production nursery. It might be more practical to schedule irrigation for daily evapotranspiration, avoid placing new plantings next to mature crops, and only separate-out plants with very high or very low crop water requirements.
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Phillips, Claire L., Sarah E. Light, Hero T. Gollany, Stephanie Chiu, Thomas Wanzek, Kylie Meyer y Kristin M. Trippe. "Can biochar conserve water in Oregon agricultural soils?" Soil and Tillage Research 198 (abril de 2020): 104525. http://dx.doi.org/10.1016/j.still.2019.104525.
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Wilder, Kris L., J. M. Hart, Arthur Poole y David D. Myrold. "FATE OF APPLIED NITROGEN FERTILIZER ON OREGON CRANBERRIES." HortScience 25, n.º 9 (septiembre de 1990): 1148c—1148. http://dx.doi.org/10.21273/hortsci.25.9.1148c.
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Little work has been done to establish the rate and timing of nitrogen fertilizer applications to optimize return from fertilizer expenditures and minimize potential for ground and surface water pollution in Oregon cranberries (Vaccinium macrocarpon Ait.). Predicting cranberry N requirements is difficult because cranberries require little N and soil tests for N are not helpful for perennial crops, especially when grown in shallow sandy soils. We used 15N-labeled ammonium sulfate to measure both plant uptake and movement of fertilizer N in a south coastal Oregon cranberry bed. A bed planted to the Stevens variety was fertilized with 15N-labelled ammonium sulfate at two rates (18 kg/ha and 36 kg/ha) applied at five phonological stages: popcorn, hook, flowering, early bud, and late bud. Plant N uptake and translocation were measured throughout the growing season in uprights, flowers, berries, and roots, Initial results indicate that when N was applied at popcorn stage approximately 12% of the N was present in the above-ground vegetative biomass at harvest. Incorporation of fertilizer N into the duff and mineral soil was measured. An estimate of fertilizer N leaching was made by trapping inorganic N below the root zone using ion exchange resin bags.
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Locascio, Salvadore J. "Management of Irrigation for Vegetables: Past, Present, and Future". HortTechnology 15, n.º 3 (enero de 2005): 482–85. http://dx.doi.org/10.21273/horttech.15.3.0482.
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Vegetables are grown throughout the U.S. on various soil types and in various climates. Irrigation is essential to supplement rainfall in all areas to minimize plant water stress. In the U.S., irrigated vegetable production accounts for about 1.9 million ha or 7.5% of the irrigated area. California, Florida, Idaho, Washington, Texas, Nebraska, Oregon, Wisconsin, and Arizona account for 80% of the U.S. production of irrigated vegetables. In the U.S., surface and subsurface (seepage) irrigation systems were used initially and are currently used on 45% of all irrigated crops with a water use efficiency of 33%. Sprinkler or overhead irrigation systems were developed in the 1940s and are currently used extensively throughout the vegetable industry. Sprinkler systems are used on 50% of the irrigated crop land and have a water use efficiency of 75%. In the late 1960s, microirrigation (drip or trickle) systems were developed and have slowly replaced many of the sprinkler and some of the seepage systems. Microirrigation is currently used on 5% of irrigated crops. This highly efficient water system (90% to 95%) is widely used on high value vegetables, particularly polyethylene-mulched tomato (Lycopersicon esculentum), pepper (Capsicum annuum), eggplant (Solanum melongena), strawberry (Fragaria ×ananassa), and cucurbits. Some advantages of drip irrigation over sprinkler include reduced water use, ability to apply fertilizer with the irrigation, precise water distribution, reduced foliar diseases, and the ability to electronically schedule irrigation on large areas with relatively smaller pumps. Drip systems also can be used as subsurface drip systems placed at a depth of 60 to 90 cm. These systems are managed to control the water table, similar to that accomplished with subsurface irrigation systems, but with much greater water use efficiency. Future irrigation concerns include continued availability of water for agriculture, management of nutrients to minimize leaching, and continued development of cultural practices that maximize crop production and water use efficiency.
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Smiley, Richard W. y Stephen Machado. "Pratylenchus neglectus Reduces Yield of Winter Wheat in Dryland Cropping Systems". Plant Disease 93, n.º 3 (marzo de 2009): 263–71. http://dx.doi.org/10.1094/pdis-93-3-0263.
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Wheat (Triticum aestivum) in low-precipitation regions of eastern Oregon and Washington is grown mostly as rainfed biennial winter wheat (10-month growing season) planted into cultivated fallow (14-month crop-free period). There are increasing trends for cultivated fallow to be replaced by chemical fallow and for spring cereals to be planted annually without tillage. Most fields are infested by the root-lesion nematodes Pratylenchus neglectus or P. thornei. A replicated multiyear experiment was conducted to compare cropping systems on soil infested by P. neglectus. Populations became greater with increasing frequency of the host crops mustard, pea, and wheat. Annual winter wheat had the highest P. neglectus populations, the lowest capacity to extract soil water, and a lower grain yield compared with wheat grown biennially or rotated with other crops. Populations of P. neglectus did not differ for cultivated versus chemical fallow. Lowest populations occurred in annual spring barley. Winter wheat yield was inversely correlated with the population of P. neglectus. Measures to monitor and to reduce the population of P. neglectus in Pacific Northwest wheat fields are recommended.
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Carlson, D. H., S. H. Sharrow, W. H. Emmingham y D. P. Lavender. "Plant-soil-water relations in forestry and silvopastoral systems in Oregon". Agroforestry Systems 25, n.º 1 (enero de 1994): 1–12. http://dx.doi.org/10.1007/bf00705702.
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Hamm, P. B., D. S. Spink, G. H. Clough y K. S. Mohan. "First Report of Bacterial Fruit Blotch of Watermelon in Oregon". Plant Disease 81, n.º 1 (enero de 1997): 113. http://dx.doi.org/10.1094/pdis.1997.81.1.113a.
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Most of the watermelons, Citrullus lanatus (Thunb.) Matsum. & Nakai, consumed in the Pacific Northwest during the summer months are grown in the southern Columbia Basin under dry (<5 cm rainfall), low relative humidity (46 to 57%), and high temperature (29 to 41°C) conditions, using transplants, plastic mulch, and drip irrigation. During May 1996, irregularly shaped, water-soaked lesions were observed on cotyledons and first true leaves of watermelon cv. Sangria transplants growing in a greenhouse. Similar lesions were observed later on older leaves in a commercial field of cv. Millionaire. Microscopic examination of symptomatic tissue revealed bacterial streaming, and isolation on nutrient agar consistently yielded numerous creamy to off-white bacterial colonies. Bacteria from purified, single colonies were Gram negative and rod shaped. Physiological characterization by the Biolog GN Bacterial Identification System (version 3.5) showed a similarity of 0.971 to the Biolog description for Acidovorax avenae subsp. citrulli. Pathogenicity of two strains was confirmed in three separate tests by hypodermic needle infiltration of cotyledons or by stab inoculation into hypocotyls of 12 to 24 21-day-old cv. Crimson Sweet seedlings with aqueous suspensions of bacteria containing approximately 6.0 × 108 CFU/ml. Inoculum was prepared from 48-h-old nutrient agar cultures. Test plants were incubated in the greenhouse at 21°C, under a 16-h photoperiod. Hypocotyl and cotyledon inoculations produced water-soaked lesions within 24 to 48 h on both the hypocotyl and cotyledons or just the cotyledon, respectively, on plants inoculated by either method. No symptoms developed on control plants infiltrated or stabbed with sterile water only. Isolations from three symptomatic seedlings yielded colonies similar in morphology to those used for inoculation. Tests of two purified cultures by Biolog indicated the bacteria were A. avenae subsp. citrulli. The symptomatic test plants were transplanted to fields, and the maturing melons developed large, dark green, water-soaked lesions with irregular margins. Similar fruit symptoms were seen in commercial fields. Labels on seed used in commercial production and in our tests warned of risks related to fruit blotch. This is the first report of bacterial fruit blotch of watermelon in Oregon. This disease may have a significant impact on watermelon production in the Columbia Basin.
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Johnson, D. E., P. E. Clark, L. L. Larson, K. D. Wilson, M. Louhaichi, T. Freeburg y J. Williams. "Cattle use of off-stream water developments across a northeastern Oregon landscape". Journal of Soil and Water Conservation 71, n.º 6 (1 de noviembre de 2016): 494–502. http://dx.doi.org/10.2489/jswc.71.6.494.
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Woods, Christopher P., Mark T. Stoelinga, John D. Locatelli y Peter V. Hobbs. "Microphysical Processes and Synergistic Interaction between Frontal and Orographic Forcing of Precipitation during the 13 December 2001 IMPROVE-2 Event over the Oregon Cascades". Journal of the Atmospheric Sciences 62, n.º 10 (1 de octubre de 2005): 3493–519. http://dx.doi.org/10.1175/jas3550.1.
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Abstract On 13–14 December 2001 a vigorous cyclonic storm passed over the Pacific Northwest, producing heavy orographic precipitation over the Cascade Mountains. This storm was one of several studied during the second field phase of the Improvement of Microphysical Parameterization through Observational Verification Experiment (IMPROVE). A wide variety of in situ and remotely sensed measurements were obtained as this storm passed over the Oregon Cascades. These measurements provided a comprehensive dataset of meteorological state parameters (temperature, pressure, humidity, winds, and vertical air velocity), polarization Doppler radar measurements, and cloud microphysical parameters (cloud liquid water, particle concentrations, size spectra, and imagery). The 13–14 December case was characterized by the passage of a tipped-forward lower-tropospheric front that extended upward to a preceding vigorous upper cold-frontal rainband, which produced clouds up to ∼8–9 km. An important difference between this storm and those studied previously over the Washington Cascades was that the prefrontal low-level airflow over the Oregon Cascades was characterized by strong westerly (as opposed to weak easterly) cross-barrier flow. Consequently, as the upper cold-frontal band passed over the Oregon Cascades there was both strong ice particle production aloft and significant production of liquid water at lower levels in the orographic lifting zone. Airborne in situ measurements, ground-based microwave radiometer measurements, and observations of snow crystals showed the simultaneous presence of high ice crystal concentrations and relatively large values of cloud liquid water aloft, and heavily rimed particles reaching the ground. Analyses indicate that a synergistic interaction occurred between the frontal and orographic precipitation.
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Adams, Katherine A., John A. Barth y R. Kipp Shearman. "Intraseasonal Cross-Shelf Variability of Hypoxia along the Newport, Oregon, Hydrographic Line". Journal of Physical Oceanography 46, n.º 7 (julio de 2016): 2219–38. http://dx.doi.org/10.1175/jpo-d-15-0119.1.
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AbstractObservations of hypoxia, dissolved oxygen (DO) concentrations < 1.4 ml L−1, off the central Oregon coast vary in duration and spatial extent throughout each upwelling season. Underwater glider measurements along the Newport hydrographic line (NH-Line) reveal cross-shelf DO gradients at a horizontal resolution nearly 30 times greater than previous ship-based station sampling. Two prevalent hypoxic locations are identified along the NH-Line, as is a midshelf region with less severe hypoxia north of Stonewall Bank. Intraseasonal cross-shelf variability is investigated with 10 sequential glider lines and a midshelf mooring time series during the 2011 upwelling season. The cross-sectional area of hypoxia observed in the glider lines ranges from 0 to 1.41 km2. The vertical extent of hypoxia in the water column agrees well with the bottom mixed layer height. Midshelf mooring water velocities show that cross-shelf advection cannot account for the increase in outer-shelf hypoxia observed in the glider sequence. This change is attributed to an along-shelf DO gradient of −0.72 ml L−1 over 2.58 km or 0.28 ml L−1 km−1. In early July of the 2011 upwelling season, near-bottom cross-shelf currents reverse direction as an onshore flow at 30-m depth is observed. This shoaling of the return flow depth throughout the season, as the equatorward coastal jet moves offshore, results in a more retentive near-bottom environment more vulnerable to hypoxia. Slope Burger numbers calculated across the season do not reconcile this return flow depth change, providing evidence that simplified two-dimensional upwelling model assumptions do not hold in this location.
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Olen, Beau. "Olen, Beau. “Irrigation Decisions for Major West Coast Crops: Water Scarcity and Climatic Determinants.” MS Thesis, Oregon State University. Outstanding Master's Thesis Honorable Mention". American Journal of Agricultural Economics 96, n.º 2 (20 de agosto de 2013): 606. http://dx.doi.org/10.1093/ajae/aat071.
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Osborne, J. J., A. L. Kurapov, G. D. Egbert y P. M. Kosro. "Intensified Diurnal Tides along the Oregon Coast". Journal of Physical Oceanography 44, n.º 7 (1 de julio de 2014): 1689–703. http://dx.doi.org/10.1175/jpo-d-13-0247.1.
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Abstract Intensified diurnal tides are found along portions of the Oregon shelf (U.S. West Coast) based on analyses of high-frequency (HF) radar surface current data and outputs of a 1-km resolution ocean circulation model. The K1 tidal currents with magnitudes near 0.07 m s−1 over a wider part of the shelf (Heceta Bank complex; 44°–44.5°N), previously predicted by Erofeeva et al., are confirmed here by newly available HF radar data. Intensified diurnal tides are also found along the narrow shelf south of Heceta Bank. In the close vicinity of Cape Blanco (42.8°N), diurnal tidal currents (K1 and O1 constituents combined) may reach 0.3 m s−1. Appreciable differences in diurnal tide intensity are found depending on whether the model is forced with tides and winds (TW) or only tides. Also, diurnal variability in wind forcing is found to affect diurnal surface velocities. For the case forced by tides alone, results strongly depend on whether the model ocean is stratified [tides only, stratified (TOS)] or not [tides only, no stratification (TONS)]. In case TONS, coastal-trapped waves at diurnal frequencies do not occur over the narrow shelf south of 43.5°N, consistent with the dispersion analysis of a linear shallow-water model. However, in case TOS, diurnal tides are intensified in that area, associated with the presence of coastal-trapped waves. Case TW produces the strongest modeled diurnal tidal motions over the entire Oregon shelf, partially due to cross-shore tidal displacement (advection) of alongshore subinertial currents. At Cape Blanco, diurnal tidal variability dominates the modeled relative vorticity spectrum, suggesting that tides may influence the separation of the alongshore coastal jet at that location.
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Watson, Nigel, Dan Shrubsole y Bruce Mitchell. "Governance Arrangements for Integrated Water Resources Management in Ontario, Canada, and Oregon, USA: Evolution and Lessons". Water 11, n.º 4 (31 de marzo de 2019): 663. http://dx.doi.org/10.3390/w11040663.
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Guidelines produced by some major international organisations create a misleading impression that Integrated Water Resources Management (IWRM) can be implemented in a standardized fashion. However, contextual conditions vary from place to place, and differences in beliefs, attitudes, customs, and norms sensibly influence interpretation and implementation. Experiences with IWRM in Oregon (USA) and Ontario (Canada) are examined with regard to scope, scale, responsibility, engagement, finances and financing, and review processes and mechanisms. Development of IWRM and the evolution of governance have been shaped by different concerns and beliefs. Oregon has adopted a locally-driven and entrepreneurial approach, whereas Ontario developed a co-operative inter-governmental approach. In both cases, IWRM governance has also evolved due to changes in funding and priorities, which have benefitted some catchments and communities more than others. Both cases provide positive examples of reflexivity and resilience, and demonstrate the importance of review processes and strong cross-scale connections for effective governance. While underlying principles may be relevant for other locations, it would be a mistake to think that either of the two approaches for IWRM could be replicated elsewhere in their exact form. Implementation of IWRM in other parts of those countries and the world should, therefore, start with careful analysis of the local context, and existing governance arrangements and governmentalities.
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Scully-Engelmeyer, Kaegan, Elise F. Granek, Max Nielsen-Pincus, Andy Lanier, Steven S. Rumrill, Patrick Moran, Elena Nilsen, Michelle L. Hladik y Lori Pillsbury. "Exploring Biophysical Linkages between Coastal Forestry Management Practices and Aquatic Bivalve Contaminant Exposure". Toxics 9, n.º 3 (2 de marzo de 2021): 46. http://dx.doi.org/10.3390/toxics9030046.
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Terrestrial land use activities present cross-ecosystem threats to riverine and marine species and processes. Specifically, pesticide runoff can disrupt hormonal, reproductive, and developmental processes in aquatic organisms, yet non-point source pollution is difficult to trace and quantify. In Oregon, U.S.A., state and federal forestry pesticide regulations, designed to meet regulatory water quality requirements, differ in buffer size and pesticide applications. We deployed passive water samplers and collected riverine and estuarine bivalves Margaritifera falcata, Mya arenaria, and Crassostrea gigas from Oregon Coast watersheds to examine forestry-specific pesticide contamination. We used non-metric multidimensional scaling and regression to relate concentrations and types of pesticide contamination across watersheds to ownership and management metrics. In bivalve samples collected from eight coastal watersheds, we measured twelve unique pesticides (two herbicides; three fungicides; and seven insecticides). Pesticides were detected in 38% of bivalve samples; and frequency and maximum concentrations varied by season, species, and watershed with indaziflam (herbicide) the only current-use forestry pesticide detected. Using passive water samplers, we measured four current-use herbicides corresponding with planned herbicide applications; hexazinone and atrazine were most frequently detected. Details about types and levels of exposure provide insight into effectiveness of current forest management practices in controlling transport of forest-use pesticides.
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Stubbs, Tami L., Ann C. Kennedy y Horace D. Skipper. "Survival of a Rifampicin-ResistantPseudomonas fluorescensStrain in Nine Mollisols". Applied and Environmental Soil Science 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/306348.
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Pseudomonas fluorescensstrain D7 (P.f.D7) is a naturally occurring soil bacterium that shows promise as a biological herbicide to inhibit growth of annual grass weeds, including downy brome (Bromus tectorumL.), in crop- and rangelands.Pseudomonas fluorescensstrain D7rif (P.f.D7rif) is a rifampicin-resistant strain ofP.f.D7. One of the greatest obstacles to successful biological weed control is survival of the organism under field conditions. Nine soils in the taxonomic order of Mollisols, collected from downy brome-infested areas of the Western and Central United States, were inoculated withP.f.D7rif and incubated in the laboratory to determine the effects of soil type, soil properties, incubation temperature, and soil water potential on survival ofP.f.D7rif over 63 days. Silt loam soils from Lind, Washington, and Moro, Oregon, sustained the highestP.f.D7rif populations, and recovery was the lowest from Pendleton, Oregon soil. Survival and recovery ofP.f.D7rif varied with soil type and temperature but not with the two soil water potentials tested. After 63 days,P.f.D7rif was recovered at levels greater than log 5.5 colony forming units (CFU) g−1soil from five of the nine test soils, a level adequate to suppress downy brome under field or range conditions.
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Chen, Chengci, William A. Payne, Richard W. Smiley y Michael A. Stoltz. "Yield and Water-Use Efficiency of Eight Wheat Cultivars Planted on Seven Dates in Northeastern Oregon". Agronomy Journal 95, n.º 4 (2003): 836. http://dx.doi.org/10.2134/agronj2003.0836.
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Chen, Chengci, William A. Payne, Richard W. Smiley y Michael A. Stoltz. "Yield and Water-Use Efficiency of Eight Wheat Cultivars Planted on Seven Dates in Northeastern Oregon". Agronomy Journal 95, n.º 4 (julio de 2003): 836–43. http://dx.doi.org/10.2134/agronj2003.8360.
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Parke, Jennifer L., Brian J. Knaus, Valerie J. Fieland, Carrie Lewis y Niklaus J. Grünwald. "Phytophthora Community Structure Analyses in Oregon Nurseries Inform Systems Approaches to Disease Management". Phytopathology® 104, n.º 10 (octubre de 2014): 1052–62. http://dx.doi.org/10.1094/phyto-01-14-0014-r.
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Nursery plants are important vectors for plant pathogens. Understanding what pathogens occur in nurseries in different production stages can be useful to the development of integrated systems approaches. Four horticultural nurseries in Oregon were sampled every 2 months for 4 years to determine the identity and community structure of Phytophthora spp. associated with different sources and stages in the nursery production cycle. Plants, potting media, used containers, water, greenhouse soil, and container yard substrates were systematically sampled from propagation to the field. From 674 Phytophthora isolates recovered, 28 different species or taxa were identified. The most commonly isolated species from plants were Phytophthora plurivora (33%), P. cinnamomi (26%), P. syringae (19%), and P. citrophthora (11%). From soil and gravel substrates, P. plurivora accounted for 25% of the isolates, with P. taxon Pgchlamydo, P. cryptogea, and P. cinnamomi accounting for 18, 17, and 15%, respectively. Five species (P. plurivora, P. syringae, P. taxon Pgchlamydo, P. gonapodyides, and P. cryptogea) were found in all nurseries. The greatest diversity of taxa occurred in irrigation water reservoirs (20 taxa), with the majority of isolates belonging to internal transcribed spacer clade 6, typically including aquatic opportunists. Nurseries differed in composition of Phytophthora communities across years, seasons, and source within the nursery. These findings suggest likely contamination hazards and target critical control points for management of Phytophthora disease using a systems approach.
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Qin, Ruijun, Christos Noulas, Don Wysocki, Xi Liang, Guojie Wang y Scott Lukas. "Application of Plant Growth Regulators on Soft White Winter Wheat under Different Nitrogen Fertilizer Scenarios in Irrigated Fields". Agriculture 10, n.º 7 (20 de julio de 2020): 305. http://dx.doi.org/10.3390/agriculture10070305.
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Lodging in cereal crops can result in yield loss and harvesting difficulties for growers. Application of plant growth regulator (PGR) has been an indispensable management practice to reduce lodging problems that are often exacerbated during high wind growing conditions and/or high nitrogen (N)/water environments, but the data is limited in the Columbia Basin of Oregon. The objective of this research was to evaluate the effect of two PGR products (chlormequat chloride-CC, trinexapac-ethyl-TE) at different rates and application timings on two soft white winter wheat varieties (ORCH-102 and SY Ovation). Crop growth (stem height and thickness), yield-related (spike density as ears m−2, seeds per spike, grain weight) and quality parameters (test weight, protein) were measured for two cropping seasons from October 2017 to July 2019 following the application of the two PGR products at tillering (GS21-26), stem elongation (GS30-32), and/or flag leaf (GS37-39) stages under a high-N fertilizer scenario. In both growing seasons, no lodging problems were recorded for any treatments. The plant height was reduced after PGR application, but the impact on stem thickness was limited. PGR application slightly affected wheat yield, yield components, testing weight, and protein level in both growing seasons. Our results suggested that the effect of PGR application is relatively limited if no lodging problem occurred.
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Hansen, E. M. y P. B. Hamm. "Canker diseases of Douglas-fir seedlings in Oregon and Washington bareroot nurseries". Canadian Journal of Forest Research 18, n.º 8 (1 de agosto de 1988): 1053–58. http://dx.doi.org/10.1139/x88-159.
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Canker diseases in northwestern forest nurseries have been referred to collectively as top blight. To distinguish among the various symptoms and their associated fungi, we made systematic observations of and isolations from Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings through two crop cycles in four northwestern nurseries, and suspect fungi were subjected to pathogenicity testing. Five diseases were distinguished. Hypocotyl rot, caused by Fusariumoxysporum, kills seedlings during their first growing season. Upper stem canker, caused by Phomaeupyrena and Fusariumroseum, girdles seedlings in midstem in the fall of their 1st year. Lower stem canker, also caused by P. eupyrena and F. roseum, kills seedlings in the winter or early spring of their 2nd year and is associated with soil collars built up by splashing water. Botrytis and Phomopsis cankers occasionally kill new shoots during the 2nd year. Not all diseases are damaging every year or in all nurseries.
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Neilson, John D., Glen H. Geen y Daniel Bottom. "Estuarine Growth of Juvenile Chinook Salmon (Oncorhynchus tshawytscha) as Inferred from Otolith Microstructure". Canadian Journal of Fisheries and Aquatic Sciences 42, n.º 5 (1 de mayo de 1985): 899–908. http://dx.doi.org/10.1139/f85-114.
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The growth of juvenile chinook salmon (Oncorhynchus tshawytscha) in the Sixes River Estuary, Oregon, was inferred from otolith microstructure. Otolith increments appeared to be formed daily, on average, and a transition between those produced during freshwater residence and estuary residence was apparent. Otolith microstructure was also examined with respect to time series of water temperature, population density, and benthic standing crop data. While the results supported the hypothesis of food-limited growth, elevated water temperatures in midsummer may have decreased food conversion efficiencies, thus also contributing to an observed growth rate decline. It was also found that from counts of otolith increments formed during freshwater life, fish that hatched relatively late tended to spend less time in freshwater before moving downstream to the estuary.
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Love, Charlotte, Brian Skahill, John England, Gregory Karlovits, Angela Duren y Amir AghaKouchak. "Integrating Climatic and Physical Information in a Bayesian Hierarchical Model of Extreme Daily Precipitation". Water 12, n.º 8 (6 de agosto de 2020): 2211. http://dx.doi.org/10.3390/w12082211.
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Extreme precipitation events are often localized, difficult to predict, and available records are often sparse. Improving frequency analysis and describing the associated uncertainty are essential for regional hazard preparedness and infrastructure design. Our primary goal is to evaluate incorporating Bayesian model averaging (BMA) within a spatial Bayesian hierarchical model framework (BHM). We compare results from two distinct regions in Oregon with different dominating rainfall generation mechanisms, and a region of overlap. We consider several Bayesian hierarchical models from relatively simple (location covariates only) to rather complex (location, elevation, and monthly mean climatic variables). We assess model predictive performance and selection through the application of leave-one-out cross-validation; however, other model assessment methods were also considered. We additionally conduct a comprehensive assessment of the posterior inclusion probability of covariates provided by the BMA portion of the model and the contribution of the spatial random effects term, which together characterize the pointwise spatial variation of each model’s generalized extreme value (GEV) distribution parameters within a BHM framework. Results indicate that while using BMA may improve analysis of extremes, model selection remains an important component of tuning model performance. The most complex model containing geographic and information was among the top performing models in western Oregon (with relatively wetter climate), while it performed among the worst in the eastern Oregon (with relatively drier climate). Based on our results from the region of overlap, site-specific predictive performance improves when the site and the model have a similar annual maxima climatology—winter storm dominated versus summer convective storm dominated. The results also indicate that regions with greater temperature variability may benefit from the inclusion of temperature information as a covariate. Overall, our results show that the BHM framework with BMA improves spatial analysis of extremes, especially when relevant (physical and/or climatic) covariates are used.
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Tomiczek, Tori, Anna Wargula, Pedro Lomonaco, Sabella Goodwin, Dan Cox, Andrew Kennedy y Patrick Lynett. "PHYSICAL MODEL INVESTIGATION OF PARCEL SCALE MANGROVE EFFECTS ON FLOW HYDRODYNAMICS AND PRESSURES AND LOADS IN THE BUILT ENVIRONMENT". Coastal Engineering Proceedings, n.º 36v (28 de diciembre de 2020): 1. http://dx.doi.org/10.9753/icce.v36v.waves.1.
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Rising seas, tropical cyclones, and tsunamis threaten increasingly populated coastal areas, leaving coastal communities searching for sustainable, resilient adaptation solutions to mitigate the impacts of chronic and acute coastal flood hazards. This work specifically investigates parcel-scale effects of the Rhizophora mangle (red mangrove) species during extreme wave and/or storm surge conditions. We constructed 100 physical models of the Rhizophora species' trunk-prop root system on a 1:16 scale, and conducted tests in Oregon State University's Directional Wave Basin to measure the effects of mangroves of varying cross-shore thickness on water surface elevation, water velocities, and load reduction on idealized inland structural elements. The presence of mangroves affected hydrodynamic conditions near the mangroves and reduced pressures and forces on inland structures.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/XjtCmHYvgVQ
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Shock, Myrtle P., Clinton C. Shock, Erik B. G. Feibert, Nancy L. Shaw, Lamont D. Saunders y Ram K. Sampangi. "Cultivation and Irrigation of Fernleaf Biscuitroot (Lomatium dissectum) for Seed Production". HortScience 47, n.º 10 (octubre de 2012): 1525–28. http://dx.doi.org/10.21273/hortsci.47.10.1525.
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Native grass, forb, and shrub seed is needed to restore rangelands of the U.S. Intermountain West. Fernleaf biscuitroot [Lomatium dissectum (Nutt.) Mathias & Constance] is a desirable component of rangelands. Commercial seed production is necessary to provide the quantity and quality of seed needed for rangeland restoration and reclamation efforts. Fernleaf biscuitroot has been used for hundreds if not thousands of years in the western United States as a source of food and medicine. Knowledge about fernleaf biscuitroot is confined to ethnobotanical reports, evaluation of some of its chemical constituents, and its role in rangelands. Products derived from fernleaf biscuitroot are sourced from wild plant populations. Little is known about fernleaf biscuitroot cultivation or its seed production. Variations in spring rainfall and soil moisture result in highly unpredictable water stress at flowering, seed set, and seed development of fernleaf biscuitroot. Water stress is known to compromise seed yield and quality for other seed crops. Irrigation trials were conducted at the Oregon State University Malheur Experiment Station at Ontario, OR, a location within the natural environmental range of fernleaf biscuitroot. It was anticipated that supplemental irrigation would be required to produce a seed crop in all years. Fernleaf biscuitroot was established through mechanical planting and cultivation on 26 Oct. 2005 in a randomized complete block design with four replicates; plot size was 9.1 m × 3.04 m wide. Irrigation treatments were 0 mm, 100 mm, and 200 mm/year applied in four equal treatments 2 weeks apart, timed to begin with flowering and continue through seed formation. First flowering occurred in the third year after planting. Seed production increased from the fourth through the sixth year. Optimal irrigation for seed production was calculated as 140 mm/year.
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McANULTY, J. M., W. E. KEENE, D. LELAND, F. HOESLY, B. HINDS, G. STEVENS y D. W. FLEMING. "Contaminated drinking water in one town manifesting as an outbreak of cryptosporidiosis in another". Epidemiology and Infection 125, n.º 1 (agosto de 2000): 79–86. http://dx.doi.org/10.1017/s0950268899004136.
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In early 1992 we identified an outbreak of cryptosporidiosis in Oregon and sought to identify and control its source. We used a series of studies to identify risk factors for illness : (i) a case-control study among employees of a long-term-care facility (LTCF); (ii) a matched case-control study of the general community; (iii) a cohort study of wedding attendees; and (iv) a cross-sectional survey of the general community. Drinking Talent water was associated with illness in the LTCF (OR = 22·7, 95% CI = 2·7–1009·0), and in the community (matched OR = 9·5, 95% CI 2·3–84·1). Drinking Talent water was associated with illness only among non-Talent residents who attended the wedding (P < 0·001) and in the community (RR = 6·5, 95% CI 3·3–12·9). The outbreak was caused by contaminated municipal water from Talent in the absence of a discernible outbreak among Talent residents, suggesting persons exposed to contaminated water may develop immunity to cryptosporidiosis.
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Yin, Chuntao, Katherine McLaughlin, Timothy C. Paulitz, Duncan R. Kroese y Christina H. Hagerty. "Population Dynamics of Wheat Root Pathogens Under Different Tillage Systems in Northeast Oregon". Plant Disease 104, n.º 10 (octubre de 2020): 2649–57. http://dx.doi.org/10.1094/pdis-03-19-0621-re.
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No-till or direct seeding can be described as seeding directly into the crop stubble from the previous season without use of tillage. A reduction in tillage can result in many benefits, including increased soil organic matter, increased water holding capacity, and reduced fuel costs. However, the effect of no-till and reduced tillage on crop root disease profiles is poorly understood. To study the effect of tillage on disease dynamics, soil samples were collected from commercial wheat fields representing a wide range of tillage strategies in fall 2016 and fall 2017. Because precipitation might affect soilborne diseases, wheat fields located across a diverse gradient of precipitation zones of the dryland Pacific Northwest were selected. Fusarium spp., Pythium spp., and Rhizoctonia spp. were quantified from soil samples using soil dilution plating and quantitative PCR (qPCR) assays. Results of dilution plating showed that the colony counts of Fusarium, Pythium, and Rhizoctonia at the genus level were negatively associated with tillage. However, the same patterns were not observed when specific causal agents of Fusarium, Pythium, and Rhizoctonia that are known to be pathogenic on wheat were quantified with qPCR. Furthermore, precipitation affected the population density of some fungal pathogens (F. culmorum, P. ultimum, and R. solani AG 8). Within the scope of inference of this study, results of this study indicate that the benefits of adopting reduced tillage likely outweigh potential risk for increased root disease.
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Smiley, Richard W. "Water and Temperature Parameters Associated with Winter Wheat Diseases Caused by Soilborne Pathogens". Plant Disease 93, n.º 1 (enero de 2009): 73–80. http://dx.doi.org/10.1094/pdis-93-1-0073.
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Wheat in eastern Oregon is produced mostly as a 2-year rotation of winter wheat and summer fallow. Maximum agronomic yield potential is expected with early September planting dates but actual yields are generally highest for plantings made in mid-October. Field experiments with sequential planting dates from early September to December were performed over 4 years. Associations among yield, disease incidence, and 19 moisture and temperature parameters were evaluated. Incidence of Cephalosporium stripe, crown rot, eyespot, and take-all decreased as planting was delayed. Crown rot and eyespot were negatively correlated more significantly and more frequently with temperature than moisture parameters, and take-all was more associated with moisture than temperature. Rhizoctonia root rot was unrelated to planting date and climatic parameters. Crown rot was identified most frequently (4 of 5 tests) as an important contributor to yield suppression but yield was most closely associated (R2 > 0.96) with effects from a single disease in only two of five location–year tests. Yield was most related to combinations of diseases in three of five tests, complicating development of disease modules for wheat growth-simulation models.
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Anderson, Kim A. y Eugene Johnson. "Bioavailable Organochlorine Pesticides in a Semi-Arid Region of Eastern Oregon, USA, as Determined by Gas Chromatography with Electron-Capture Detection". Journal of AOAC INTERNATIONAL 84, n.º 5 (1 de septiembre de 2001): 1371–82. http://dx.doi.org/10.1093/jaoac/84.5.1371.
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Abstract A group of dissolved-bioavailable organochlorine (OC) pesticides and inorganic anions in water and total OC pesticides in sediments were measured in the Malheur Watershed, a semi-arid region in the western United States, over a 2-year period. OC pesticide levels were compared with those from a 1990 study of the lower section of the river, the most recent data available. After calculating the dissolved fraction from the 1990, study it seems that DDD and dieldrin levels have decreased in the water by 50–70%, while DDE and DDT have changed little. Although banned nearly 30 years ago, DDT is still persistent throughout the Malheur River basin/watershed because it was found in all water samples tested. All of the OC pesticides tested during the 2-year study are well below the criterion continuous concentration for aquatic community exposure as defined by the U.S. Environmental Protection Agency (EPA). OC pesticides appear to be decreasing, however, at lower Ontario there remains a human health risk (EPA Human Health Risk Water Quality Criteria) for DDT, because this criteria includes daily consumption of water and fish from the river. Overall, although the upper forest watershed sites have lower OC pesticide concentrations, they represent an important contribution to the total DDT load to this watershed, a source not previously acknowledged. The large increase in DDT and ΣDDT between the Ontario sites may indicate a possible historical point source of contamination or historical preferential deposition of contamination. Normalized sediment (ΣDDT/organic carbon) strongly correlates with dissolved water ΣDDT.
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Williams, J. D., S. Dun, D. S. Robertson, J. Q. Wu, E. S. Brooks, D. C. Flanagan y D. K. McCool. "WEPP simulations of dryland cropping systems in small drainages of northeastern Oregon". Journal of Soil and Water Conservation 65, n.º 1 (1 de enero de 2010): 22–33. http://dx.doi.org/10.2489/jswc.65.1.22.
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Cao, Z., M. Dai, W. Evans, J. Gan y R. Feely. "Diagnosing CO<sub>2</sub> fluxes in the upwelling system off the Oregon–California coast". Biogeosciences 11, n.º 22 (24 de noviembre de 2014): 6341–54. http://dx.doi.org/10.5194/bg-11-6341-2014.
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Abstract. It is generally known that the interplay between the carbon and nutrients supplied from subsurface waters via biological metabolism determines the CO2 fluxes in upwelling systems. However, quantificational assessment of such interplay is difficult because of the dynamic nature of both upwelling circulation and the associated biogeochemistry. We recently proposed a new framework, the Ocean-dominated Margin (OceMar), for semi-quantitatively diagnosing the CO2 source/sink nature of an ocean margin over a given period of time, highlighting that the relative consumption between carbon and nutrients determines if carbon is in excess (i.e., CO2 source) or in deficit (i.e., CO2 sink) in the upper waters of ocean margins relative to their off-site inputs from the adjacent open ocean. In the present study, such a diagnostic approach based upon both couplings of physics–biogeochemistry and carbon–nutrients was applied to resolve the CO2 fluxes in the well-known upwelling system off Oregon and northern California of the US west coast, using data collected along three cross-shelf transects from the inner shelf to the open basin in spring/early summer 2007. Through examining the biological consumption on top of the water mass mixing revealed by the total alkalinity–salinity relationship, we successfully predicted and semi-analytically resolved the CO2 fluxes showing strong uptake from the atmosphere beyond the nearshore regions. This CO2 sink nature primarily resulted from the higher utilization of nutrients relative to dissolved inorganic carbon (DIC) based on their concurrent inputs from the depth. On the other hand, the biological responses to intensified upwelling were minor in nearshore waters off the Oregon–California coast, where significant CO2 outgassing was observed during the sampling period and resolving CO2 fluxes could be simplified without considering DIC/nutrient consumption, i.e., decoupling between upwelling and biological consumption. We reasoned that coupling physics and biogeochemistry in the OceMar model would assume a steady state with balanced DIC and nutrients via both physical transport and biological alterations in comparable timescales.
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Kurapov, A. L., J. S. Allen, G. D. Egbert y R. N. Miller. "Modeling Bottom Mixed Layer Variability on the Mid-Oregon Shelf during Summer Upwelling". Journal of Physical Oceanography 35, n.º 9 (1 de septiembre de 2005): 1629–49. http://dx.doi.org/10.1175/jpo2768.1.
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Abstract Results from a model of wind-driven circulation are analyzed to study spatial and temporal variability in the bottom mixed layer (BML) on the mid-Oregon shelf in summer 2001. The model assimilates acoustic Doppler profiler velocities from two cross-shore lines of moorings 90 km apart to provide improved accuracy of near-bottom velocities and turbulence variables in the area between the mooring lines. Model results suggest that the response of the BML thickness to upwelling- and downwelling-favorable winds differs qualitatively between an area of “simple” bathymetric slope at 45°N and a wider shelf area east of Stonewall Bank (44.5°N). At 45°N, the BML grows in response to downwelling-favorable conditions, in agreement with known theories. East of Stonewall Bank, the BML thickness is increased following upwelling events. In this area, the southward upwelling jet detaches from the coast and flows over a wider part of the Oregon shelf, creating conditions for Ekman pumping near the bottom. Based on computations of bottom stress curl, the vertical pumping velocity in this area may reach 15 m day−1 following periods of intensified upwelling-favorable winds. A column of denser, near-bottom water upwelled over the Ekman flow convergence area is tilted as a result of vertical shear in horizontal velocities, causing unstable stratification and convective overturning. As a result of this process, BML thickness values east of Stonewall Bank can be in excess of 20 m following upwelling, comparable to maximum values at 45°N following downwelling.
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Bothwell, Max L. "Eutrophication of Rivers by Nutrients in Treated Kraft Pulp Mill Effluent". Water Quality Research Journal 27, n.º 3 (1 de agosto de 1992): 447–72. http://dx.doi.org/10.2166/wqrj.1992.031.
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Abstract In 1972, the start up of a 1200 ADT/day bleached kraft pulp mill in Kamloops, British Columbia, resulted in a massive increase in algal standing crop in the Thompson River below Kamloops Lake. While phosphorus loading from the pulp mill was believed to be responsible for this change, the actual elevation in dissolved phosphorus concentration downstream of the discharge was below the detection limit (3 µg PL-1) of the analytical procedure used in the joint Federal-Provincial Task Force Study of the Thompson River in 1973-75. Research at Environment Canada’s Experimental Troughs Apparatus (EXTRA) located at Chase, B.C., has proven that the ambient concentration of phosphorus required to saturate the specific growth rate of attached diatom communities with a concomitant increase in algal standing crop is very low (ca. 1 ug PL1). Hence, although the concentration of dissolved phosphorus in kraft mill effluent (KME) is typically below 0.5 mg PL1 (ca. 1 µg PL1 total phosphorus), even at in-river dilutions of 100-fold, the steady-state elevation of soluble phosphorus is high enough to stimulate algal production in rivers which are phosphorus-limited. In rivers that are nitrogen-limited, nitrogen in fully treated KME can also stimulate algal production. The atomic ratio of available N and P in the McKenzie River, Oregon, is ca. 2:1 clearly indicating a nitrogen-limited system. The discharge of secondarily treated KME to this river near Springfield, Oregon, has also increased algal production. Stream-side flume experiments measuring the effect of treated KME additions on algal growth have shown that the concentration of dissolved inorganic nitrogen (DIN) available for algal uptake (ammonium-N; ~200 µg NL-1 and nitrate-N; ~ 50 ug N L-1) in KME was high enough to increase specific growth rates from 0.30 to 0.56 divisions d-1 during the summer, even with the effluent completely diluted in the river (0.5% v/v). At other seasons of the year, KME did not stimulate algal growth at concentrations occurring in the river. In an experiment with phosphorus added in pulses to river algal communities, the attached diatoms were able to rapidly uptake the phosphorus spikes and continue growing rapidly. Algae exposed to a P concentration of 60 µg PL-1 for only one min each hour grew as fast as those algae exposed to a continuous enrichment concentration of 1 µg PL-1. This showed the importance of stable nutrient loading characteristics in controlling eutrophication of rivers.
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Lee, E. Henry, Peter A. Beedlow, Ronald S. Waschmann, David T. Tingey, Charlotte Wickham, Steve Cline, Michael Bollman y Cailie Carlile. "Douglas-fir displays a range of growth responses to temperature, water, and Swiss needle cast in western Oregon, USA". Agricultural and Forest Meteorology 221 (mayo de 2016): 176–88. http://dx.doi.org/10.1016/j.agrformet.2016.02.009.
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Cao, Z., M. Dai, W. Evans, J. Gan y R. Feely. "Diagnosing CO<sub>2</sub> fluxes in the upwelling system off the Oregon coast". Biogeosciences Discussions 11, n.º 5 (21 de mayo de 2014): 7389–412. http://dx.doi.org/10.5194/bgd-11-7389-2014.
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Abstract. It is generally known that the interplay between the carbon and nutrients supplied from subsurface waters via biological metabolism would determine the CO2 fluxes in upwelling systems. However, quantificational assessment of such interplay is difficult because of the dynamic nature of both upwelling circulation and the associated biogeochemistry. In this study, the diagnosis approach based upon the carbon/nutrient mass balance in the Ocean-dominated Margin (OceMar) framework was applied to resolve the CO2 fluxes in the well-known upwelling system in the US west coast off Oregon, using the data collected along two cross-shelf transects from the inner shelf to the open basin in spring/early summer 2007. Through examining the biological consumption on top of the water mass mixing built upon the total alkalinity–salinity relationship, we successfully predicted and semi-analytically resolved the CO2 fluxes showing strong uptakes from the atmosphere beyond the nearshore regions, primarily resulting from the higher utilization of nutrients relative to dissolved inorganic carbon (DIC) based on their concurrent inputs from the depth. On the other hand, we showed significant CO2 outgassing in the nearshore regions associated with intensified upwelling and minor biological consumption, where CO2 fluxes could be simplified without considering DIC/nutrient consumption. We reasoned that our approach in conceptualizing OceMar would be in a steady state with balanced DIC and nutrients via both physical transport and biological alterations in comparable timescales.
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Curiel, John A., Gary D. Slade, Thu-Mai L. Christian, Sophia Lafferty-Hess, Thomas M. Carsey y Anne E. Sanders. "Referendum opposition to fluoridation and health literacy: a cross-sectional analysis conducted in three large US cities". BMJ Open 9, n.º 2 (febrero de 2019): e022580. http://dx.doi.org/10.1136/bmjopen-2018-022580.
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ObjectiveTo explore health literacy as a marker of voter confusion in order to understand the basis for public opposition to community water fluoridation.DesignA cross-sectional study.SettingConducted in three large US cities of San Antonio, Texas (602 voting precincts); Wichita, Kansas (171 voting precincts); and Portland, Oregon (132 voting precincts). Precinct-level voting data were compiled from community water fluoridation referendums conducted in San Antonio in 2002, Wichita in 2012 and Portland in 2013.ParticipantsVoter turnout expressed as a percentage of registered voters was 38% in San Antonio (n=2 92 811), 47% in Wichita (n=129 199) and 38% in Portland (n=164 301).Main outcome measuresThe dependent variable was the percentage of votes in favour of fluoridating drinking water. Precinct-level voting data were mapped to precinct scores of health literacy, and to US Census and American Community Survey characteristics of race/ethnicity, age, income and educational attainment. Multilevel regression with post-stratification predicted the precinct mean health literacy scores, with weights generated from the National Association of Adult Literacy health literacy survey, with item response theory computed scoring for health literacy. Predictive models on voter support of community water fluoridation were compared using robust linear regression to determine how precinct-level characteristics influenced voter support in order to determine whether health literacy explained more variance in voting preference than sociodemographic characteristics.ResultsPrecinct-level health literacy was positively associated with voter turnout, although sociodemographic characteristics were better predictors of turnout. Approximately 60% of voters opposed community water fluoridation in Wichita and Portland, whereas in San Antonio, a small majority (53%) voted in favour of it. Models suggest that a one SD increase in health literacy scores predicted a 12 percentage point increase support for community water fluoridation.ConclusionEducational attainment and health literacy are modifiable characteristics associated with voting precincts' support for community water fluoridation.
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Parke, Jennifer L., Neelam R. Redekar, Joyce L. Eberhart y Fumiaki Funahashi. "Hazard Analysis for Phytophthora Species in Container Nurseries: Three Case Studies". HortTechnology 29, n.º 6 (diciembre de 2019): 745–55. http://dx.doi.org/10.21273/horttech04304-19.
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Phytophthora species cause crop losses and reduce the quality of greenhouse and nursery plants. Phytophthora species can also be moved long distances by the plant trade, potentially spreading diseases to new hosts and habitats. Phytosanitary approaches based on quarantines and endpoint inspections have reduced, but not eliminated, the spread of Phytophthora species from nurseries. It is therefore important for plant production facilities to identify potential sources of contamination and to take corrective measures to prevent disease. We applied a systems approach to identify sources of contamination in three container nurseries in Oregon, California, and South Carolina. Surface water sources and recaptured runoff water were contaminated with plant pathogenic species at all three nurseries, but one nursery implemented an effective disinfestation treatment for recycled irrigation water. Other sources of contamination included cull piles and compost that were incorporated into potting media, infested soil and gravel beds, used containers, and plant returns. Management recommendations include preventing contact between containers and contaminated ground, improving drainage, pasteurizing potting media ingredients, steaming used containers, and quarantine and testing of incoming plants for Phytophthora species. These case studies illustrate how recycled irrigation water can contribute to the spread of waterborne pathogens and highlight the need to implement nursery management practices to reduce disease risk.
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Manter, Daniel K., Rick G. Kelsey y Joseph J. Karchesy. "Photosynthetic Declines in Phytophthora ramorum-Infected Plants Develop Prior to Water Stress and in Response to Exogenous Application of Elicitins". Phytopathology® 97, n.º 7 (julio de 2007): 850–56. http://dx.doi.org/10.1094/phyto-97-7-0850.
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Phytophthora ramorum, causal agent of sudden oak death, is responsible for widespread oak mortality in California and Oregon, and has the potential to infect 100 or more species. Symptoms range from stem girdling and shoot blight to leaf spotting. In this study, we examined the physiological impacts of P. ramorum infection on Rhododendron macrophyllum. In stem-inoculated plants, photosynthetic capacity (Vcmax) significantly declined by ≈21% 3 weeks after inoculation in visibly asymptomatic leaves. By 4 weeks, after the development of significant stem lesions and loss in water transport capacity, water stress led to stomatal closure and additional declines in photosynthetic capacity. We also report the isolation, characterization, and biological activity of two P. ramorum elicitins. Both elicitins were capable of inducing a hypersensitive-like response in one incompatible (Nicotiana tabacum SR1) and three compatible hosts (R. macrophyllum, Lithocarpus densiflorus, and Umbellularia californica). Infiltration of leaves from all three compatible hosts with both P. ramorum elicitins caused significant declines in chlorophyll fluorescence (Fv /Fm). For all four species, the loss of photosynthetic capacity was directly proportional to H+ uptake and ethylene production, two common components of the hypersensitive response. This is the first report of elicitins causing photosynthetic declines in compatible hosts independent of plant water stress.
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Johnson, D. E., L. L. Larson, K. D. Wilson, P. E. Clark, J. Williams y M. Louhaichi. "Cattle use of perennial streams and associated riparian areas on a northeastern Oregon landscape". Journal of Soil and Water Conservation 71, n.º 6 (1 de noviembre de 2016): 484–93. http://dx.doi.org/10.2489/jswc.71.6.484.
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Cole, Elizabeth, Amanda Lindsay, Michael Newton y John D. Bailey. "Vegetation Control and Soil Moisture Depletion Related to Herbicide Treatments on Forest Plantations in Northeastern Oregon". Weed Technology 32, n.º 4 (3 de mayo de 2018): 461–74. http://dx.doi.org/10.1017/wet.2018.24.
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AbstractReforestation in the Inland Northwest, including northeastern Oregon, USA, is often limited by a dry climate and soil moisture availability during the summer months. Reduction of competing vegetative cover in forest plantations is a common method for retaining available soil moisture. Several spring and summer site preparation (applied prior to planting) herbicide treatments were evaluated to determine their efficacy in reducing competing cover, thus retaining soil moisture, on three sites in northeastern Oregon. Results varied by site, year, and season of application. In general, sulfometuron (0.14 kg ai ha–1 alone and in various mixtures), imazapyr (0.42 ae kg ha–1), and hexazinone (1.68 kg ai ha–1) resulted in 3 to 17% cover of forbs and grasses in the first-year when applied in spring. Sulfometuron+glyphosate (2.2 kg ha–1) consistently reduced grasses and forbs for the first year when applied in summer, but forbs recovered in the second year on two of three sites. Aminopyralid (0.12 kg ae ha–1)+sulfometuron applied in summer also led to comparable control of forb cover. In the second year after treatment, forb cover in treated plots was similar to levels in nontreated plots, and some species of forbs had increased relative to nontreated plots. Imazapyr (0.21 and 0.42 kg ha–1) at either rate, spring or summer 2007, or at lower rate (0.14 kg ha–1) with glyphosate in summer, provided the best control of shrubs, of which snowberry was the dominant species. Total vegetative cover was similar across all treatments seven and eight years after application, and differences in vegetation were related to site rather than treatment. In the first year after treatment, rates of soil moisture depletion in the 0- to 23-cm depth were correlated with vegetative cover, particularly late season soil moisture, suggesting increased water availability for tree seedling growth.
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Rai, Subash P., Aaron T. Wolf y Nayan Sharma. "Hydropolitics and hydropolitical dynamics between India and Nepal: an event-based study". Water Policy 19, n.º 5 (20 de mayo de 2017): 791–819. http://dx.doi.org/10.2166/wp.2017.063.
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India and Nepal not only share common borders and cultures, but also share precious freshwater sources, i.e., rivers. Rivers have been discussed often in the political corridors because they cross international borders, which transform water reserves into a competitive resource and lead to hydropolitical dynamics between riparian countries. Nepal and India are two of the major riparian nations that share the mighty and complex Ganges Basin. The objective here was to study the more-than-a-century-old hydro-diplomacy between India and Nepal, passing through tumultuous political scenarios to understand how water relations have been shaped and reshaped with time. For this, a database of historical individual events/actions of water cooperation and conflict from 1874 to 2014 was compiled. These events/actions were ranked by intensity, using precise definitions of conflict and cooperation as suggested by the Transboundary Freshwater Dispute Database under the Basins at Risk project formulated at Oregon State University. Statistical analyses indicated cooperative events greatly outnumbered conflictive events. Out of 351 events, only 4% were conflictive, 92% were cooperative, and the remaining 4% were neutral. The study revealed an abundance of cooperative events; however, when seen through the lens of conflict-cooperation levels, the findings indicated a moderately positive cooperation, without much concrete action.
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F. Almutairi, Khalid, David R. Bryla y Bernadine C. Strik. "Potential of Deficit Irrigation, Irrigation Cutoffs, and Crop Thinning to Maintain Yield and Fruit Quality with Less Water in Northern Highbush Blueberry". HortScience 52, n.º 4 (abril de 2017): 625–33. http://dx.doi.org/10.21273/hortsci11533-16.
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Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions, such as Oregon, Washington, and California. New strategies are needed to maintain yield and fruit quality with less water. To address the issue, three potential options for reducing water use, including deficit irrigation, irrigation cutoffs, and crop thinning, were evaluated for 2 years in a mature planting of northern highbush blueberry (Vaccinium corymbosum L. ‘Elliott’). Treatments consisted of no thinning and 50% crop removal in combination with either full irrigation at 100% of estimated crop evapotranspiration (ETc), deficit irrigation at 50% ETc (applied for the entire growing season), or full irrigation with irrigation cutoff for 4–6 weeks during early (early- to late-green fruit) or late (fruit coloring to harvest) stages of fruit development. Stem water potential was similar with full and deficit irrigation but, regardless of crop thinning, declined by 0.5–0.6 MPa when irrigation was cutoff early and by >2.0 MPa when irrigation was cutoff late. In one or both years, the fruiting season was advanced with either deficit irrigation or late cutoff, whereas cutting off irrigation early delayed the season. Yield was unaffected by deficit irrigation in plants with a full crop load but was reduced by an average of 35% when irrigation was cutoff late each year. Cutting off irrigation early likewise reduced yield, but only in the 2nd year when the plants were not thinned; however, early cutoff also reduced fruit soluble solids and berry weight by 7% to 24% compared with full irrigation. Cutting off irrigation late produced the smallest and firmest fruit with the highest soluble solids and total acidity among the treatments, as well as the slowest rate of fruit loss in cold storage. Deficit irrigation had the least effect on fruit quality and, based on these results, appears to be the most viable option for maintaining yield with less water in northern highbush blueberry. Relative to full irrigation, the practice reduced water use by 2.5 ML·ha−1 per season.
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Thomas, G. L., S. L. Thiesfeld, S. A. Bonar, R. N. Crittenden y G. B. Pauley. "Estimation of Submergent Plant Bed Biovolume using Acoustic Range Information". Canadian Journal of Fisheries and Aquatic Sciences 47, n.º 4 (1 de abril de 1990): 805–12. http://dx.doi.org/10.1139/f90-093.
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Acoustic measurements of the distance between the water surface, top of the aquatic plants, and bottom of the water column were made using chart recording echosounders. The vertical cross sectional area (m2), height (m), biovolume (m3), of aquatic plant beds and variances were computed for three surveys of Devils Lake, Oregon, in May, July, and September, 1986 when coefficients of variation for the plant bed biovolume estimates were 0.18, 0.05, and 0.06, respectively (n = 14). Coefficients of variation for plant biomass estimates (g/m2) computed from SCUBA quadrat samples collected concurrently with the acoustic surveys, were 0.98 (n = 48), 0.81 (n = 90), and 1.05 (n = 90), respectively. The higher precision of the biovolume estimates allow for a 5- to 18-fold greater capability to detect a change in the mean. The lower costs of the biovolume estimates allow for a 10- to 33-fold greater precision-for-cost. The plant bed biovolume variable contains ecologically different information than the biomass variable in that it provides a direct estimate of the amount of aquatic habitat in a lake that is influenced by plants; it should prove useful for evaluating plant control practices and possibly for studying plant-fish interactions.
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Hansen, E. M., Jean-Claude Streito y Claude Delatour. "First Confirmation of Phytophthora lateralis in Europe". Plant Disease 83, n.º 6 (junio de 1999): 587. http://dx.doi.org/10.1094/pdis.1999.83.6.587b.
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Phytophthora lateralis, a pathogen of Chamaecyparis lawsoniana (Port-Orford cedar or Lawson's cypress), was confirmed in France, but isolates from Germany identified as P. lateralis or “similar to” P. lateralis proved to be P. gonapodyides. Previously, P. lateralis was known only from western North America, where it has been destructive in nurseries, ornamental plantings, and the forest since its introduction about 1920 (1). Reports from other locations have proved to be misidentifications or impossible to confirm. In France, P. lateralis was isolated and identified from C. lawsoniana on two occasions (1996 and 1998) in different parts of the country, probably stemming from a single original infestation of young, potted, greenhouse-propagated cedars in a commercial nursery. German isolates were from an old culture collection and from irrigation water in a nursery growing a wide range of woody ornamentals. Identifications were confirmed by comparison (2) with authentic isolates. P. lateralis isolates from France and Oregon formed laterally proliferating, elongated obpyriform sporangia that under the conditions of our tests could be dislodged by agitation, leaving a short pedicel. Also, brown chlamydospores formed laterally on the hyphae or terminally on a short stalk and oospores were not formed on standard media. Radial growth was about 2 mm per day. In contrast, sporangia of German isolates and known P. gonapodyides isolates were similar. They exhibited nested pro liferation, were broader than P. lateralis sporangia, and were not readily dehiscent. Some P. gonapodyides isolates, including those from Germany, formed chlamydospores, but these were nearly all catenulate and not lateral, and isolates grew faster (3 to 4 mm per day). Pathogenicity was tested by stem inoculation of C. lawsoniana. P. lateralis from France and Oregon produced lesions averaging 4.7 cm after 2 months (range 2.0 to 8.1 cm, six replicates per isolate, five isolates) while the six replicates of the two German isolates averaged 1.2- and 1.6-cm lesion lengths. Furthermore, sequences of internal transcribed spacer (ITS) DNA from French and Oregon P. lateralis isolates were identical, while sequences of German isolates were similar to P. gonapodyides (J. Duncan and D. Cooke, personal communiation). P. lateralis is a dangerous pathogen of C. lawsoniana and is also pathogenic to Taxus spp. (1), although less aggressive on this host. If established, it would be a serious threat to the widespread ornamental plantings and scattered forest plantations of C. lawsoniana in Europe. References: (1) E. M. Hansen and K. J. Lewis. Compendium of Conifer Diseases. American Phytopathological Society, 1997. (2) C. M. Tucker and J. A. Milbrath. Mycologia 34:94, 1942.
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King, Bradely A., Krista C. Shellie, David D. Tarkalson, Alexander D. Levin, Vivek Sharma y David L. Bjorneberg. "Data-Driven Models for Canopy Temperature-Based Irrigation Scheduling". Transactions of the ASABE 63, n.º 5 (2020): 1579–92. http://dx.doi.org/10.13031/trans.13901.
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HighlightsArtificial neural network modeling was used to predict crop water stress index lower reference canopy temperature.Root mean square error of predicted lower reference temperatures was <1.1°C for sugarbeet and Pinot noir wine grape.Energy balance model was used to dynamically predict crop water stress index upper reference canopy temperature.Crop water stress index for sugarbeet was well correlated with irrigation and soil water status.Crop water stress idex was well correlated with midday leaf water potential of wine grape.Abstract. Normalized crop canopy temperature, termed crop water stress index (CWSI), was proposed over 40 years ago as an irrigation management tool but has experienced limited adoption in production agriculture. Development of generalized crop-specific upper and lower reference temperatures is critical for implementation of CWSI-based irrigation scheduling. The objective of this study was to develop and evaluate data-driven models for predicting the reference canopy temperatures needed to compute CWSI for sugarbeet and wine grape. Reference canopy temperatures for sugarbeet and wine grape were predicted using machine learning and regression models developed from measured canopy temperatures of sugarbeet, grown in Idaho and Wyoming, and wine grape, grown in Idaho and Oregon, over five years under full and severe deficit irrigation. Lower reference temperatures (TLL) were estimated using neural network models with Nash-Sutcliffe model efficiencies exceeding 0.88 and root mean square error less than 1.1°C. The relationship between TLL minus ambient air temperature and vapor pressure deficit was represented with a linear model that maximized the regression coefficient rather than minimized the sum of squared error. The linear models were used to estimate upper reference temperatures that were nearly double the values reported in previous studies. A daily CWSI, calculated as the average of 15 min CWSI values between 13:00 and 16:00 MDT for sugarbeet and between 13:00 and 15:00 local time for wine grape, were well correlated with irrigation events and amounts. There was a significant (p < 0.001) linear relationship between the daily CWSI and midday leaf water potential of Malbec and Syrah wine grapes, with an R2 of 0.53. The data-driven models developed in this study to estimate reference temperatures enable automated calculation of the CWSI for effective assessment of crop water stress. However, measurements taken under conditions of wet canopy or low solar radiation should be disregarded as they can result in irrational values of the CWSI. Keywords: Canopy temperature, Crop water stress index, Irrigation scheduling, Leaf water potential, Sugarbeet, Wine grape.
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Petersen, Louis E. "1057 THE PRODUCTION OF CULINARY HERBS IN THE U.S. VIRGIN ISLANDS: CONSTRAINTS AND SOLUTIONS". HortScience 29, n.º 5 (mayo de 1994): 580b—580. http://dx.doi.org/10.21273/hortsci.29.5.580b.
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In the U.S. Virgin Islands (USVI), herbs and spices are in great demand, mainly for culinary purposes. These crops include thyme, basil, oregano, parsley, chives, fennel, rosemary and marjoram. Based on estimated total marketable yield of 25 growers in 1993, 10,264 kg of fresh culinary herbs were produced in USVI. During the same period, 21,207 kg of various herbs were imported to the USVI. These data clearly show that local demand for herbs exceeds domestic production. Constraints which limit increased production in USVI include small farm size, limited water resources, absence of mechanization and limited information on crop management practices. Many herb growers use traditional farming practices and for the most part avoid modern approaches to cultivation. Appropriate cultural and management practices (e.g. drip irrigation, mulching, fertilizer, etc.) could potentially boost production and increase overall efficiency despite the reality of small farm acreages. This paper will describe the current status of herb production in the USVI, constraints to production and proposed solutions to improve its economic prospect.
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Bryla, David R. y Robert G. Linderman. "Implications of Irrigation Method and Amount of Water Application on Phytophthora and Pythium Infection and Severity of Root Rot in Highbush Blueberry". HortScience 42, n.º 6 (octubre de 2007): 1463–67. http://dx.doi.org/10.21273/hortsci.42.6.1463.
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A 2-year study was done in Oregon to determine the effects of irrigation method and level of water application on the development of root rot in northern highbush blueberry (Vaccinium corymbosum L. ‘Duke’). Plants were grown on mulched, raised beds and irrigated by overhead sprinklers, microsprays, or drip at 50%, 100%, and 150% of the estimated crop evapotranspiration requirement. Soil at the site was a silty clay loam. By the end of the first season, plants were largest with drip, intermediate-sized with microsprays and smallest with sprinklers; however, this was not the case the next season. By the end of year 2, plants irrigated by drip had less canopy cover, fewer new canes, lower pruning weights, and only half the shoot and root dry weight as plants irrigated by sprinklers or microsprays. Destructive sampling revealed that the field was infested by root rot. Less growth with drip was association with higher levels of infection by the root pathogen, Phytophthora cinnamomi. Phytophthora infection increased with water application, regardless of irrigation method, but averaged 14% with drip and only 7% with sprinklers and microsprays. Roots were also infected by Pythium spp. Pythium infection likewise increased with the total amount of water applied but, unlike P. cinnamomi, was similar among irrigation methods. Overall, drip irrigation maintained higher soil water content near the base of the plants than sprinklers and microsprays, resulting in conditions more favorable to root rot. Sprinklers and microsprays may be better alternatives than drip at sites prone to problems with the disease.
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Ruggiero, Nicole y George L. Kral. "Prescribed cattle grazing as a tool for native prairie management: Lessons from the Tualatin River basin, Oregon". Journal of Soil and Water Conservation 73, n.º 3 (2018): 74A—78A. http://dx.doi.org/10.2489/jswc.73.3.74a.
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Putnam, M. L. "First Report of Leaf Blight and Stem Dieback of St. John's-Wort Caused by Diploceras hypericinum in Oregon". Plant Disease 84, n.º 11 (noviembre de 2000): 1250. http://dx.doi.org/10.1094/pdis.2000.84.11.1250b.
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St. John's-wort, Hypericum perforatum L., was formerly considered a noxious weed in the Pacific Northwest and is now grown commercially for its medicinal properties. In May 1999, plants from a 5-ha field in Jefferson County, OR, were observed with yellowing leaves and stem dieback. Lower leaves showed marginal necrosis or circular, expanding, uniformly brown, unremarkable leaf lesions that appeared randomly over the lamina and consumed from a quarter to nearly the entire leaf area. Remaining leaf tissue was chlorotic, and affected leaves eventually abscised. Infection of the stems resulted in girdling lesions 0.5 to 1.0 cm in length that caused chlorosis, wilting, and eventual dieback of tissues distal to the lesion. Diploceras hypericinum (Cesati) Diedicke was sporulating on affected stems and leaves. The fungus was isolated from surface-disinfested tissue onto 1.5% water agar. A single-spore isolate was used to inoculate 10-month-old plants raised from seed in sand. Spores from 6-week-old cultures grown on 50% potato-dextrose agar were harvested, suspended in phosphate buffer with 0.2% gelatin (PBG), and sprayed onto three plants using a DeVilbiss atomizer. Inoculum concentration was 7 × 103 and 3 ml per plant were used (plants were 8 to 10 cm tall). Three control plants were sprayed with sterile PBG. Inoculated and control plants were separately bagged to retain moisture and maintained at 22 to 25°C. Four days later, inoculated plants exhibited leaf spots similar to those originally observed, followed by stem dieback. D. hypericinum was isolated from all inoculated plants but not from control plants. The known distribution of D. hypericinum is France, Germany, Portugal, Sweden, Greece, and Ontario, Canada (1,2). This is the first report of D. hypericinum causing leaf blight and stem dieback of St. John's-wort in the United States. References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN. (2) T. R. Nag Raj. 1993. Coelomycetous Anamorphs with Appendage-bearing Conidia. Mycologue Publications, Waterloo, Canada.
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Tarasoff, Catherine S., Daniel A. Ball y Carol A. Mallory-Smith. "Extreme Ionic and Temperature Effects on Germination of Weeping Alkaligrass (Puccinellia distans), Nuttall's Alkaligrass (Puccinellia nuttalliana) and Kentucky Bluegrass (Poa pratensis)". Weed Science 55, n.º 4 (agosto de 2007): 305–10. http://dx.doi.org/10.1614/ws-06-170.1.
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The introduced species weeping alkaligrass, and the native species Nuttall's alkaligrass, two of the most salt-tolerant C3 grasses found in arid and semiarid environments of western North America, occur within the Grande Ronde valley of eastern Oregon. Both species occur as weeds within Kentucky bluegrass seed fields and subsequently as grass seed contaminants. Two separate germination experiments were conducted to understand better the seed germination biology of these two species compared to Kentucky bluegrass under negative water potentials or high temperature conditions. Results of these studies indicate that although all three species benefited from an ionic enhancement associated with NaCl, weeping alkaligrass was the most drought and salt tolerant of the three species. Dry seeds of weeping alkaligrass were also particularly tolerant to high temperatures with no differences in germination at temperatures below 50 C, indicating that seed viability under nonirrigated field conditions should be unaffected by high soil temperatures. Under soil temperature conditions as high as 40 C, moist Kentucky bluegrass seeds had the greatest germination rates, indicating that this species should benefit from irrigation more than the other two species.
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Stone, Jeffrey. "Peer review report 1 on “Douglas-fir displays a range of growth responses to temperature, water, and Swiss needle cast in western Oregon, USA”". Agricultural and Forest Meteorology 217 (enero de 2016): 330. http://dx.doi.org/10.1016/j.agrformet.2016.11.058.
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