In Oregon perennial and annual grass seed cropping systems conservation management practices and their impacts on soil health and soil microbial community is not well understood. There is strong motivation to employ conservation tillage and other conservation practices to curb atmospheric carbon levels and improve soil health. However, the few...
In the Columbia Basin, pre-plant soil fumigation is commonly used in potato production for pest control, but fumigation can kill non-target organisms within the soil, result in unintended shifts in the microbial community, and disrupt long-term soil health. Cover crops have been shown to strongly influence the numbers and communities...
“Active carbon” is a rapidly cycling soil organic carbon (SOC) fraction that acts as an energy and nutrient source for the microbial community. Dilute permanganate oxidation has been used to measure an “active carbon” fraction with the assumption that permanganate oxidation mimics enzymatic decomposition. Permanganate oxidizable carbon (PoxC) has become...
Biochar is a highly porous, carbon-rich residue produced by thermochemical conversion (pyrolysis) of plant biomass and carbonaceous organic materials under oxygen-controlled conditions. Chars produced by this process tend to have high ion-exchange capacities and, when added to soil, increase retention of water and nutrients and improve soil aggregation, porosity, and...
Deeply weathered soils in tropical rainforests and savannas are classified as Ferralsols according to the World References Bases for Soil Resources (WRB). Ferralsols are most nearly akin to the Oxisols order defined in the US Soil Taxonomy. The acidity, low cation exchange capacity, and strong phosphorus retention by the oxidic...
Arctic warming is exposing thawing permafrost to repeated freeze-thaw, a disruptive process that can alter soil biogeochemistry and physical structure. To investigate the impact of permafrost exposure to freeze-thaw, soil response was tested across three scales: 2.5 cm³ aggregates, a forested hillslope, and two sites at contrasting latitudes. XCT imaging...
Various soil tests are routinely used in the United States to predict soil lime requirement. New non-hazardous methods have recently been proposed for adoption in Oregon, however the accuracy of these methods for Oregon soils has not been established. The objectives of this investigation were: (a) to document and describe...
Nutrient limitation constrains tree growth in many managed forests. Nitrogen (N) is the most common limiting nutrient, but high N supply can shift limitation to other nutrients, particularly phosphorus (P) and the base cations calcium (Ca), magnesium (Mg), and potassium (K). As different soil minerals have different capacities to supply...
Coastal Temperate Rainforests of western North America are carbon dense ecological regions of great importance due to their high biological productivity and climatic conditions leading to the natural accumulation of soil organic carbon (SOC). Yet, the distribution of SOC remains understudied in the CTR environments, particularly in upland mineral soils,...