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  • Author or Editor: Ray William x
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Extension workers often identify production, marketing, managerial, or educational constraints that reduce agricultural efficiencies. In Oregon, problems expressed by growers of several horticultural crops appeared to have a common soil management component. Some Christmas tree growers, for example, complained about poor vigor and growth of 2nd- or 3rd-cycle trees that were planted immediately after harvest of the previous crop. Growers reasoned that poor growth (and reduced marketability) might be caused by increasing concentrations of herbicide residues that resulted from yearly applications of atrazine or hexazinone, rather than soil erosion and related soil management problems. Grape producers and lily bulb growers were concerned about soil erosion, since crops were planted parallel to the slope. Frequent mechanical harvesting of brambles led to growers’ fears of soil compaction, while fruit growers noted slower rates of water infiltration in orchards where natural vegetation is managed with a flail compared to areas interplanted with a sod.

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Altering the physical or chemical nature of the crop production environment through introduction of cover crops or other non-crop vegetation may amend the impact of various pests on vegetable crops. Current work is focused on the interaction of cereal cover crops and respective management systems with weed emergence and growth, white mold (Sclerotinia sclerotiorum) incidence, symphylan (Scutigerella immaculata) population dynamics, soil food-web structure, and crop yield in snap bean production systems. Research has demonstrated the potential of cover crop residues, tillage, and a single broadcast application of a postemergence herbicide to control summer annual weeds. Additionally, white mold incidence was significantly decreased by both reduced tillage conditions and flailed barley cover crop residues in one year of research. Two years of research indicate that symphylan density can be reduced by flailing spring-planted cereals before crop planting.

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Learning style preferences contribute to predictable actions by people. Basic researchers are fundamentally different than applied researchers in horticulture. Dilemmas associated with pesticides, worker protection, water, and labor issues often are related to differences in perception by relational versus linear thinkers. A participatory discussion will focus on these differences and how they can be combined to create dynamic and creative learning around complex issues facing horticulturists and consumers during the 1990's.

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Red alder (Alnus rubra Bong) and black locust (Robina pseudoacacia L.) were intercropped in different planting patterns with sweet corn (Zea mays L.) in Corvallis, Oregon. In both years, sweet corn yield in alley cropping systems was significantly reduced when trees occupied more than 20 % of the total area. In the first year, higher yield were harvested in corn rows adjacent to the trees which compensated for reduced cropping area in the alley cropping systems. Low sweet corn yield coincided with high pruning biomass production. Red alder pruning biomass was small in the first year but equivalent to black locust in the following year. In the second year, soil microbial counts at planting time showed that bacterial and fungal activity in the tree rows was significantly higher compared to corn rows. At corn harvest, fungal activity was higher in tree rows and in corn rows adjacent to trees compared to corn rows more distant to the trees or corn rows in monocropping systems. It might be that higher sweet corn yield in rows next to the trees not only are the result of an increase in the amount of intercepted light but that below ground effects such as nitrogen mineralization from increased microbial activity or nitrogen transfer from the trees to the crop play an important role.

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Field experiment on production systems of `Selva' day-neutral and `Totem' June-bearing strawberry was established in 1995 on the spring-killed cover crop mulched plots using randomized complete-block design. Seven soil cover treatments consisted of `Wheeler' rye (Secale cereale) and `Micah' and `Steptoe' barley (Hordium vulgare), `Micah' residue applied on soil surface, a wedge of perlite (artificial medium) placed next to strawberry row, perlite with `Wheeler' rye, and no treatment were used. During the early summer, cover crops were replanted between strawberry rows and mowed down after 6 weeks. In both cultivars, plant growth doubled during mid-summer, and `Micah'on surface produced better growth than the growth in other treatments. No significant difference was found on CO2 assimilation rate (mmol·m–2·s–1), leaflet length, and number of leaves and runners among treatments (P ≥ 0.1). Yield of `Totem' was ignored during the establishment year. In `Selva', `Micah' residue on surface produced 36% more crowns per plant and the greatest total yield than that of any other treatment. `Micah' on surface produced 50% more shoot biomass and 45% greater yield compared to `Micah' barley planted in the plot. Total `Selva' yield was 61% greater in perlite treatment than the yield in perlite with `Wheeler' rye and 31% greater than the control treatment. Comparison of `Selva' strawberry total yield and average fruit production between cover crops vs. control treatment using non-orthogonal contrast indicated no significant difference might suggests no detrimental interaction between cover crops and strawberry.

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Fall-planted cover crops killed in spring is practiced in strawberry cultivation in different regions of the North America. These systems have shown significant weed suppression and conservation of soil without significant yield reduction in strawberry. During the establishment season, this study was initiated to assess weed suppression with cover crops (`Wheeler' rye and `Micah' and `Steptoe' barley) along with perlite, an artificial plant medium. Strawberry (`Selva' and `Totem') plant growth and weed biomass were measured during 1995-96 season. Small-seeded summer annual weeds were suppressed in cover crop treatments compared to control treatment. `Micah' barley in growth phase suppressed more than 81% of the total weed biomass compared to control plots with no cover crop in early spring. However, in early summer, cover crop residues failed to suppress different types of weeds 60 days after killing of cereal with herbicide (2% glyphosate). Distinct differences in strawberry plant growth were evident between the cover crop treatments and non-cover crop treatments including `Micah' applied on surface. Strawberry growth was doubled during 10 July to 15 Aug. in both cultivars. `Micah' barley applied on surface produced better growth in both strawberry varieties than the growth in other treatments. `Micah' barley applied on soil surface produced 50% more strawberry shoot biomass may indicate the root competition between cover crops and strawberry.

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Guayule is a desert shrub that has been researched extensively for the purpose of developing it into a commercially viable source of high quality, hypoallergenic latex and rubber. Traditional breeding techniques have dramatically increased rubber yields, but genetic engineering techniques have the potential to increase rubber concentration in each plant while accelerating the development time of high-yielding guayule lines. Development of techniques to measure the flow of pollen from transgenic to non-transgenic plants is necessary to learn how to limit potential contamination of the environment due to transgene escape. Thus, the purpose of this work was to develop the methodology to quickly screen for transgenic seedlings. Guayule lines AZ 101, AZ-2, and N6-5, which were transformed with plasmids containing the NPTII gene that confers kanamycin resistance, were planted in a field surrounded by border rows and satellite plots of non-transgenic guayule. Seeds of known transgenic and non-transgenic guayule (controls) and seed collected from the non-transgenic plants were germinated and treated with an aerosol solution containing kanamycin at concentrations of 200, 300, and 400 mg·L-1. Kanamycin caused seedlings to develop blotchy yellow leaves at all concentrations. Kanamycin at 300 mg·L-1 was determined to be ideal for its time-to-symptom development and its lack of symptom severity found when treated at 400 mg·L-1. Plants showing kanamycin resistance or kanamycin damage were confirmed using PCR.

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Gaps in learning occur when synthesis of factual information is assumed, delayed, or taken out of a realistic context. We are exploring wholes, simulations, case studies, natural resource issues, and interactive learning as ways to improve life-long inquiry and action. Realistic situations are described for student/adult participatory learning. Both group and individual learning are blended where facts are integrated at the “moment of learning” rather than a teaching moment. Teachers become coaches, facilitators, and providers of spontaneous lecturettes. Enthusiasm, participation and ownership by students and adults are spectacular. We've invented farmer-scientist focus sessions (FSFS) along with Rapid, iterative, interactive posters (RIIP). It's fun and seems to meet people's needs for complex topics and issues.

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In a world of rapid and unpredictable change, land grant universities must refocus their efforts on becoming more effective learning organizations. This poster addresses the critical opportunities, challenges, and tensions LGUs will face as they seek to enhance the continuous learning process and thereby flourish in the future.

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A project was initiated in which a collaborative and mutual learning process was emphasized to (1) improve farmer designed research and to facilitate learning among farmers, research and extension, agribusiness and government agencies; (2) to enhance vegetable production systems by improving farm profitability, protecting water quality, and enhancing long-term soil productivity. The poster displays mutual learning that occurred during each step of the following process:

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