Soils are a globally significant carbon (C) pool and have the potential to respond to elevated CO2 and environmental changes through positive feedback cycles that enhance the turnover of soil organic matter (SOM). Understanding the mechanisms governing the turnover of SOM is particularly important for modeling the fate of C...
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David D. Myrold Kate Lajtha
Soils are a globally significant carbon (C) pool and have the
Total organic carbon, total nitrogen, microbial respiration and enzyme
activity (β-glucosidase) were measured on several horizons of a Dayton silt loam
(fine, montmorillonitic, mesic, Typic Albaqualf) soil cropped to annual ryegrass
under two straw residue management systems. The study evaluated the effects
of annual burning of straw residues or annual...
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...
Intimate associations with reactive metal species permanently protect soil organic matter (SOM) from microbial access and oxidation, contributing to the build-up of organic carbon (C) stocks in soils. It is increasingly recognized, however, that such associations can be reversible and that reactive metal species might even facilitate the oxidation of...
Two native shrub species (Piliostigma reticulatum and Guiera senegalensis) are prominent vegetation components in farmers’ fields in Senegal. However, their role in nutrient cycling and ecosystem function has largely been overlooked. A study including both laboratory and field experiments was conducted to evaluate potential biophysical interactions of the two shrub...
Algae can be used in a variety of wastewater systems to capture nutrients while fixing carbon dioxide from the atmosphere. I conducted field trials at three locations in Oregon with both corn and potato crops to assess the agronomic value and environmental impact of using the resulting algal biomass as...
“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...
Most carbon (C) transformations in soil are carried out by a diverse and complex soil microbial community. The size and composition of the soil microbial community is determined by poorly understood interactions between the quantity and chemical composition of plant inputs, as well as climate. Given the metabolic diversity of...
A variety of soil properties have been proposed and tested as potential
indicators of soil quality. This study was conducted in an effort to produce a
standardized soil quality index for systems in Oregon. Soils in both forested and
agricultural systems were sampled in a wide variety of locations, climates,...
A method based on fatty acid (FA) analysis is used to profile microbial community structure (MCS). Various extraction protocols are available, which alter the types of FAs extracted from soils. The more time consuming but widely used protocol extracts only FAs from phospholipids (PLFA). This technique is desirable because PLFAs...