The Indiana Carbon Storage Project

Author

John Brenner,
Colorado State University

Executive Summary 

Quantifying the Change in Greenhouse Gas Emissions due to Natural Resource Conservation Practice Application in Indiana. A collaborative effort between USDA NRCS and CSU - NREL.

Land managers have long known the importance of soil organic matter in maintaining the productivity and sustainability of agricultural land. More recently, interest has developed in the potential for using agricultural soils to sequester C and mitigate increasing atmospheric CO2 by adopting practices that increase standing stocks of carbon in soil organic matter and vegetation. Practices that increase the amount of CO2 taken up by plants (through photosynthesis), which then enter the soil as plant residues, tend to increase soil C stocks. Likewise, management practices that reduce the rate of decay or “turnover” of organic matter in soils will also tend to increase carbon stocks.

In 1999, we initiated a state-wide assessment of how management decisions involving cropping and tillage systems affect soil organic matter. Our approach utilized a variety of resource data (on climate, soils, land use and management), long-term field experiment results, and the Century EcoSystem Soil Organic Matter Computer Model. An initial Phase I study of cropland in Indiana utilized existing information on climate, soils and management factors (e.g., drainage, crops grown, production levels and tillage systems) and estimated Indiana to be a slight source of 0.12 million metric tonnes per year (MMT) of C to the atmosphere. From this Phase I study, it was apparent that the individual counties had land use information, including management histories of cropping rotations, drainage histories, fertilizer rates, and conservation practices that were not available in published databases. It was also ascertained from the Phase 1 study that local land managers wanted additional information about C sequestration, and local conservation districts were willing to report any C sequestered due to conservation practices to the US Department of Energy (DOE).

The Phase II study was started in 1999 and involved all 92 counties. This general approach of involving every county within a state had recently been successfully used in a similar study in Iowa. For the project to be successful, it was necessary to devise a means of improving communication with the local land managers and collecting the local data. The Carbon Sequestration Rural Appraisal (CSRA) survey instrument was modified, tested and implemented in each county using an electronic spreadsheet format. Individually tailored spreadsheets were prepared for each county and electronically transmitted to Indiana. Local data only available at the county level was filled in each spreadsheet. All spreadsheets were electronically transmitted back to Fort Collins, CO when completed. This local data provided vi additional inputs into the Century Model that were not available in previously published databases, and refined the output for the individual counties and the soils and crop/tillage systems within each county. Century estimates for over 800,000 different scenarios showing the C changes are now available in the Indiana CarbOn Management Evaluation Tool (COMET) database. The county summaries for the amounts of C sequestered in 1990-1999 are also available.

The Phase II assessment for Indiana suggests that agricultural soils are currently (based on 1999 data) sequestering 0.77 MMT of carbon per year (equivalent to 2.8 MMT of CO2 per year), largely through increased adoption of conservation practices over the past 10 to 20 years. Mineral soils are estimated to be sequestering 1.46 MMT of C per year (5.4 MMT of CO2), but the cultivation of organic soils are a source of 0.68 MMT of C (2.5 MMT of CO2) back to the atmosphere. Excluding the impact from the cultivation of organic soils, sound conservation practices on Indiana cropland is sequestering C and is equivalent to an offset of 2.7% of Indiana’s 1999 fossil fuel carbon emissions.

Prepared By:
Phil Smith, John Brenner, Keith Paustian, George Bluhm, Jan Cipra, Mark Easter, Ted Elliott, Kendrick Killian, David Lamm, Jill Schuler and Steve Williams.

Primary Contacts:
Keith Paustian, Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO
John Brenner, USDA-NRCS, Fort Collins, CO