Filters: Tags: Soil carbonates (X)
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Shifts in plant community structure in shrub and grass-dominated ecosystems are occurring over large land areas in the western US. It is not clear what effect this vegetative change will have on rates of carbon and nitrogen cycling, and thus long-term ecosystem productivity. To study the effect of different plant species on the decomposability of soil organic substrates and rates of C- and N-cycling, we conducted laboratory incubations of soils from a 15-yr-old experimental plot where big sagebrush (Artemisia tridentata Nutt.) and crested wheatgrass (Agropyron desertorum [Fisch.] Schult.) plants had been planted in a grid pattern. Soil samples collected from beneath crested wheatgrass had significantly greater total...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Carbon storage,
Decomposition,
Gross mineralization,
Microbial biomass,
Nitrification,
Shifts in plant community structure in shrub and grass-dominated ecosystems are occurring over large land areas in the western US. It is not clear what effect this vegetative change will have on rates of carbon and nitrogen cycling, and thus long-term ecosystem productivity. To study the effect of different plant species on the decomposability of soil organic substrates and rates of C- and N-cycling, we conducted laboratory incubations of soils from a 15-yr-old experimental plot where big sagebrush (Artemisia tridentata Nutt.) and crested wheatgrass (Agropyron desertorum [Fisch.] Schult.) plants had been planted in a grid pattern. Soil samples collected from beneath crested wheatgrass had significantly greater total...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Carbon storage,
Decomposition,
Gross mineralization,
Microbial biomass,
Nitrification,
In the western Grand Canyon, fluvial terraces and pediment surfaces, both associated with a Pleistocene basalt flow, document Quaternary aggradation and downcutting by the Colorado River, illuminate the river's response to overload and the end of overload, and allow calibration of soil-carbonate stages and determination of downcutting rates. Four downcutting?aggradation cycles are present. Each begins with erosion of older deposits to form a new river channel in which a characteristic suite of deposits is laid down. The current cycle (I) started 700 yr B.P. The oldest (IV) includes the 603,000 � 8000 to 524,000 � 7000 yr Black Ledge basalt flow, emplaced when the river channel was 30 m higher than it is now. The...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Arizona,
Grand Canyon,
Quaternary Research,
cyclic stream response,
soil carbonates,
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