Forests are one of the largest repositories of terrestrial C. Understanding factors that drive organic matter transformations and nutrient efflux from these systems is therefore highly important. Temperate forests are of particular significance due to the large fraction of C that is stored below ground in the soil. Characterizing nutrient...
This publication is a technical and practical guide for soil acidification in commercial fields. It explains the soil chemistry involved, how to determine whether pH adjustment is feasible, and methods for acidifying soil. This guide is divided into five sections:
• Understanding soil pH
• The problem—iron chlorosis
• Causes...
Application of N fertilizer is a common forest management practice in the Pacific
Northwest, yet the long-term influence of fertilization on forest soil properties is not well known. Although elevated N often increases mineralization of C and N from labile organic matter, negative effects have been documented in recalcitrant organic...
This publication is a reference guide for forest soils productivity and management. Main topics include (1) understanding and managing risk, (2) soil characteristics that affect productivity, (3) soil survey information for forestland managers/management of soil erosion, (4) managing mass wasting risk, (5) managing soil disturbance, and (6) maintaining adequate nutrient...
Successful conservation management requires an understanding of how species respond to intervention. Native and exotic species may respond differently to management interventions due to differences arising directly from their native or exotic origin (i.e., provenance) or from differences in life-history or phylogenetic lineage that are associated with provenance. Thus, selection...
Riparian zones of Pacific Northwest forests have high species diversity and abundance and act as an important interface between the aquatic and terrestrial ecosystems. In addition, riparian zones comprise a significant portion of the total buffer zone established during commercial forest production to protect aquatic ecosystems from adjacent management activities....
Surface erosion can be initiated by forest practices such as
timber harvest, road construction, and site preparation. A variety
of management and control measures can help reduce
this erosion. Surface erosion is generated by soil and operational
conditions that are conducive to or cause disturbance
and compaction. By using good...
Dissolved organic matter (DOM) plays an important role in transport of C and essential nutrients such as N, P and S. DOM is also critical for the formation of soil organic matter (SOM), which is the largest terrestrial C pool. Nonetheless, we lack a basic understanding of what controls immobilization...
Controls of substrate quality, temperature, and moisture on woody root decomposition in the Pacific Northwest were explored using chronosequences, time series, laboratory incubations, and simulation modeling approaches at three sites: Cascade Head
(CAH), H. J. Andrews (HJA), and Pringle Falls Experimental Forests (PRF). In the chronosequence study, a structural component-oriented...
Soils and other resource programs in both public land management agencies and private industry are continually being adapted to the challenges of evolving knowledge and experience in the field of forestry. This dissertation explores new ways of thinking about and using soils information in forest planning and management, with a...
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...
We investigated the root endophytic fungi of lupine using
four approaches: (1) occurrence of fungal colonization in field-collected
roots; (2) growth response of L. latifolius to inoculation
with two types of fungi; (3) structure of root colonizations of
Pinus and Lupinus by Phialocephala fortinii, a septate endophytic
fungus of lupine;...
Freeze/thaw cycles are numerous in agricultural soils of the Pacific Northwest. Potential loss of soil by erosion is high whenever a soil thaws from the surface creating a saturated soil overlying an impermeable frozen layer. Field studies were conducted to investigate the effect of surface residue on soil freezing. Residue...
Pacific Northwest prairies have become significantly reduced in extent, and in the Willamette Valley of Oregon, less than one percent of native upland prairies remain. Many species have been impacted by this extreme loss of habitat, including Castilleja levisecta (golden paintbrush), a threatened hemiparasitic forb species endemic to the Pacific...
As part of a participatory research project, where farmers and Oregon State University researchers collaborated, aspects of potato (Solanum tuberosum L.) growing systems were studied. It was determined through conversations with the farmers that quantification of certain growth parameters of potato was lacking, including dry matter accumulation, crop nitrogen (N)...
Forest harvest persists as one of the most globally important industries, and crucially provides raw wood products for both building and fuel materials. Mechanistically complex abiotic and biotic processes curb ecosystem recovery following timber harvest and it is of great importance to understand the effects of this practice on biogeochemical...
Management practices following forest harvest can affect long-term soil productivity through alteration of soil carbon (C) and nitrogen (N) pools, but processes contributing to change are poorly understood. I assessed effects of three levels of logging-debris retention in combination with initial or annual applications of competing vegetation control (CVC) following...
Hard white winter (HVVW) wheat cultivars must have superior protein quality and consistent processing quality to be successful in the Asian market. New cultivars and management strategies are needed to produce HVVW grain for both bread and noodle applications from diverse environments in the US Pacific Northwest (PNW). This study...
Nursery and greenhouse products are economically important agricultural commodities for Oregon and Washington. Nursery crops including tree seedlings can be damaged or killed by soilborne plant pathogens, which can be challenging to manage because of their persistence in soil and limited options for control. Soil solarization is a pre-planting soil...
This paper models the supply curve of carbon sequestration on Pacific Northwest rangelands. Rangeland managers have the ability to sequester carbon in agricultural soils by implementing alternative management practices on their farms. Their low adoption rate in practice suggests a high opportunity cost associated with their implementation. To increase their...