Filters: Tags: soil organic carbon (X) > Types: Journal Citation (X)
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Soil organic carbon (SOC) storage plays a major role in the global carbon cycle and is affected by many factors including land use/management changes (e.g., biofuel production-oriented changes). However, the contributions of various factors to SOC changes are not well understood and quantified. This study was designed to investigate the impacts of changing farming practices, initial SOC levels, and biological enhancement of grain production on SOC dynamics and to attribute the relative contributions of major driving forces (CO2 enrichment and farming practices) using a fractional factorial modeling design. The case study at a crop site in Iowa in the United States demonstrated that the traditional corn-soybean (CS)...
Categories: Publication;
Types: Journal Citation;
Tags: Carbon dynamics,
Soil carbon,
Soil organic carbon
Terrestrial carbon sequestration potential is widely considered as a realistic option for mitigating greenhouse gas emissions. However, this potential may be threatened by global changes including climate, land use, and management changes such as increased corn stover harvesting for rising production of cellulosic biofuel. Therefore, it is critical to investigate the dynamics of soil organic carbon (SOC) at regional or global scale. This study simulated the corn production and spatiotemporal changes of SOC in the U.S. Temperate Prairies, which covers over one-third of the U.S. corn acreage, using a biogeochemical model with multiple climate and land-use change projections. The corn production (either grain yield...
Categories: Publication;
Types: Journal Citation;
Tags: Carbon dynamics,
Carbon flux,
Carbon stock,
Soil carbon,
Soil organic carbon,
The large land area occupied by arid lands, roughly 36% to 40% globally, underscores the importance for understanding how these ecosystems function in the global carbon cycle. Few studies have directly examined soil organic carbon (SOC) dynamics and the effect of vegetation on SOC and microbial community structure in arid ecosystems. The objective of this study was to determine the effect of vegetation type on SOC dynamics in an arid, hyperthermic Sonoran Desert ecosystem. We specifically examined the influence of Prosopis velutina (mesquite), Larrea tridentata (creosote), and a combination of Bouteloua barbata, Bouteloua aristidoides, Aristida adscensionis, and Cynodon dactylon (mixed grass) vegetation types on...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Geoderma,
aggregate stability,
analysis of similarity,
arid ecosystem,
bouteloua aristidoides,
Heirarchiacal Bayesian Scaling of Soil Properties Across Urban, Agricultural, and Desert Ecoysystems
Ecologists increasingly use plot-scale data to inform research and policy related to regional and global environmental change. For soil chemistry research, scaling from the plot to the region is especially difficult due to high spatial variability at all scales. We used a hierarchical Bayesian model of plot-scale soil nutrient pools to predict storage of soil organic carbon (oC), inorganic carbon (iC), total nitrogen (N), and available phosphorus (avP) in a 7962-km2 area including the Phoenix, Arizona, USA, metropolitan area and its desert and agricultural surroundings. The Bayesian approach was compared to a traditional approach that multiplied mean values for urban mesic residential, urban xeric residential, nonresidential...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Arizona,
CAP LTER,
Ecological Applications,
Ecological Society of America,
Phoenix,
Relatively few studies have examined the ecological and biogeochemical effects of livestock grazing in southeastern Utah. In this study, we evaluated how grazing has affected soil organic carbon and nitrogen to a depth of 50 cm in grasslands located in relict and actively-grazed sites in the Canyonlands physiographic section of the Colorado Plateau. We also evaluated differences in plant ground cover and the spatial distribution of soil resources. Results show that areas used by domestic livestock have 20% less plant cover and 100% less soil organic carbon and nitrogen compared to relict sites browsed by native ungulates. In actively grazed sites, domestic livestock grazing also appears to lead to clustered, rather...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal of Arid Environments,
Moran's index,
magnetic susceptibility,
nitrogen,
soil organic carbon
Relatively few studies have examined the ecological and biogeochemical effects of livestock grazing in southeastern Utah. In this study, we evaluated how grazing has affected soil organic carbon and nitrogen to a depth of 50 cm in grasslands located in relict and actively-grazed sites in the Canyonlands physiographic section of the Colorado Plateau. We also evaluated differences in plant ground cover and the spatial distribution of soil resources. Results show that areas used by domestic livestock have 20% less plant cover and 100% less soil organic carbon and nitrogen compared to relict sites browsed by native ungulates. In actively grazed sites, domestic livestock grazing also appears to lead to clustered, rather...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal of Arid Environments,
Moran's index,
magnetic susceptibility,
nitrogen,
soil organic carbon
Analyses of carbon isotope ratios (?13C) in soil organic matter (SOM) and soil respired CO2 provide insights into dynamics of the carbon cycle. ?13C analyses do not provide direct measures of soil CO2 efflux rates but are useful as a constraint in carbon cycle models. In many cases, ?13C analyses allow the identification of components of soil CO2 efflux as well as the relative contribution of soil to overall ecosystem CO2 fluxes. ?13C values provide a unique tool for quantifying historical shifts between C3 and C4 ecosystems over decadal to millennial time scales, which are relevant to climate change and land-use change issues. We identify the need to distinguish between ?13C analyses of SOM and those of soil CO2...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Ecological Applications,
Ecological Society of America,
below ground processes and global change,
c3 and c4 ecosystems,
carbon cycle,
Recent trends of increasing woody vegetation in arid and semiarid ecosystems may contribute substantially to the North American C sink. There is considerable uncertainty, however, in the extent to which woody encroachment alters dryland soil organic carbon (SOC) and total nitrogen (TN) pools. To date, studies assessing SOC and TN response to woody plant proliferation have not explicitly assessed the variability caused by shrub age or size and subcanopy spatial gradients. These factors were quantified via spatially intensive soil sampling around Prosopis velutina shrubs in a semidesert grassland, using shrub size as a proxy for age. We found that bulk density increased with distance from the bole (P < 0.005) and...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Global Change Biology,
Prosopis,
Santa Rita Experimental Range,
carbon sequestration,
land cover change,
Annual brome grasses, Bromus japonicus and B. tectorum, are common invaders of northern mixed-grass prairie, and have been shown to alter the structure and function of prairie ecosystems, including plant biomass production and litter decomposition. To build on previous findings, our objective was to model the impact of annual brome grasses on soil organic carbon storage as a step towards forecasting ecological change. Specifically, we measured differences in carbon storage between patches dominated by annual bromes and perennial grasses, in addition to evaluating key plant functional characteristics that impact carbon storage. Using the CENTURY model, we simulated high- and low-brome vegetation based on differences...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Biological Invasions,
Century model,
Springer Netherlands,
annual brome grasses,
ecological forecasting,
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