Note: The following characters are not allowed:

', ",<, >, |, $, @, %, =, ;, &, +, (, ), /, \ Checking: action:2
Checking: titleid:274

CASMGS Insider - Add vignette

Integrating Soil Physics, Soil Chemistry and Soil Biology to Understand C Sequestration

Executive Summary 
As atmospheric levels of CO2 increase steadily, the ability of terrestrial systems to assimilate this burden of CO2 is critically linked to the amount of C sequestered in soils and to the rate that biomass is converted to and sequestered as soil C.



Linking Soil Aggregation, Organic Chemistry, and Microbial Community Composition, Diversity and Activity to Understand the Turnover and Sequestration of Soil Organic Matter in Agroecosystems.  

     
Collaborators: Serita Frey, Tim Filley, Steve Ogle, Ron Turco  

     
As atmospheric levels of CO2 increase steadily due to industrialization, the ability of terrestrial systems to assimilate this increasing burden of CO2 is critically linked to the amount of C sequestered in soils and to the rate that living terrestrial biomass is converted to and sequestered as soil C. Moreover, the rate at which this sequestered C is returned to the atmosphere, either as CO2 or CH4, is intimately linked to its bioavailability and the oxidation process. The bioavailability of C is determined both by its chemical composition and its physical location within the soil matrix. While much is known of the general composition of SOM, the specific structural characterization of SOM has proved a formidable task. Similarly, the importance of soil structure (i.e. physical protection) in determining C dynamics has received considerable recent attention; however, the link between and the relative importance of physical protection versus structural composition is largely unknown. In addition, the influence of microbial community structure/diversity on the oxidation rate of C and the interactions between microbial community structure/diversity, SOM structural composition, and physical protection warrant further study.  

     
The overall goal of the project is to elucidate the biological, chemical, and physical mechanisms controlling the long-term storage of carbon in agricultural soils. Our research efforts are designed to investigate the role of soil structure (aggregation) on the sequestration of soil organic matter SOM; elucidate the locations of plant and microbial-derived SOM constituents within soil aggregates; and quantify rates of turnover of SOM within aggregates by investigating bulk fractions as well as specific organic compounds of unique plant and microbial origin; and characterize the rate-limiting steps in the C stabilization process. The effort will also lead to an understanding of how microbial community structure, diversity and activity influence C turnover and stabilization.  

     
We have a two-tiered research approach in which participants collaborate on an across-site comparison of four long-term agricultural experiments and a field-scale 13C labeling study. Both whole soil and aggregate SOM fractions isolated from whole soil will be analyzed from samples collected from the field sites and labeling study. Four sites have been selected for an across-site comparison of aggregation, SOM structural composition, and microbial community characterization. The sites are Wooster, OH; Konza Prairie, KS; Mead, NE; and Sterling, CO. These were selected to represent the major cropping systems in the US (continuous corn, corn-soybean, wheat-fallow), and to include irrigated cropland (Mead, NE) and rangeland (Konza). We will sample a tillage comparison experiment (no-tillage versus conventional tillage) with a continuous corn rotation at Wooster, burned and unburned range plots at Konza, irrigated and rain fed corn-soybean plots at Mead, and wheat-fallow and wheat-corn-fallow plots at Sterling.  

     
We are also conducting a field-Scale 13C labeling experiment to determine where SOM fractions are located within the soil aggregate structure, how SOM structural composition changes during the decomposition process, and how microbial community structure and diversity influences the turnover and stabilization of specific plant compounds. The addition of 13C-plant materials will greatly enhance the plant-carbon signal, which is essential to unambiguously track microbial cycling and partitioning through to microbial biomarker lipids.  

     

Go Home
View Another Vignette
About |  Home |  Insider |  Institutions |  Newsletter |  Current Publications |  News |  People |  Citations |  Research |  UP 
Comments? Questions? Problems?
   Click here.
CASMGS is funded by: