Estimates of nitrogen (N) available from long-term application of organic
amendments are required to balance N inputs with crop N requirements. Two studies
were conducted to (1) determine N mineralized from organic amendments (manures
and composts) during year 2 after application, and (2) compare plant-available N
(PAN) determined via in...
A major constraint to the production of self-rooted wine grapes (Vitis vinifera) in eastern Washington is plant-parasitic nematodes. Plant-parasitic nematodes can impact grape productivity by limiting water and nutrient uptake, educing physiological changes, and extracting plant nutrients from roots, thereby reducing root biomass, plant vigor, and yield. The most commonly...
A 0.4 ha planting of blueberry (Vaccinium corymbosum L.) was established in Oct. 2006 to evaluate the effects of cultivar (Duke and Liberty), planting method (flat versus raised beds), weed management (sawdust mulch and hand-weed control; compost plus sawdust mulch with acetic acid, flaming, and hand-weeding used as needed; and...
The use of cover crops in young vineyards is not widely accepted in the Pacific Northwest due to concerns of water and nutrient competition between the cover crop and vines. The last 2 years of a 4-year study started in 2009 are reported here. The study evaluated the use of...
Interest in measuring soil quality continues to increase worldwide in view of demands on land productivity and the necessity to preserve soil resources, yet identification of suitable indicators for soil quality assessment is still evolving. This study adapted 10 biological, physical, and chemical indicators of soil quality identified by the...
Producers in the Willamette Valley of Oregon are interested in growing canola as a rotational crop in grass seed and cereal rotations. Many other Brassicaceae seed crops also are produced within the valley. Concerns of seed persistence and volunteer contamination of Brassicaceae seed crops prompted the investigation of seed persistence...
Response of agricultural crops to irrigation water deficit is well-understood at the field scale. Broader scale (watershed and county levels) studies have been less frequently performed. Data collection at the field level for extensive areas is time consuming and expensive. The importance of studies at a broader scale for evaluating...
Root rot of sweet corn in western Oregon and Washington is a significant disease that
can reduce yield of intolerant cultivars of processed sweet corn by fifty percent. Root rot
is caused by a complex of soilborne organisms, including Drechslera sp., Phoma
terrestris, and Pythium arrhenomanes. Processors have adopted tolerant...
The effect of serial (multiple-year) organic matter (OM) amendment on soil properties has been described in some cropping systems, although less is known about the effect of serially amended field soils on soil-borne plant diseases. The objectives of this study were to describe the effects of the third and fourth...
Methods for obtaining accurate, spatially explicit estimates of biomass density in tropical forests are required to reduce uncertainties in the global carbon cycle, and to support international climate agreements and emerging carbon markets. Three-dimensional (3-D) remote sensing techniques sensitive to the vertical structure of vegetation provide a unique opportunity for...