THE IMPACT OF CO2 FERTILIZATION ON SOIL CARBON STORAGE BELOW A FOREST

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: NRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 0189418
• Grant No.: 2001-35107-11242
• Cumulative Award Amt.: $125,015.00
• Proposal No.: 2001-01277
• Project Start Date: Nov 1, 2001
• Project End Date: Oct 31, 2004
• Grant Year: 2002
• Program Code: [25.0]- (N/A)

Recipient Organization
BOSTON COLLEGE
140 COMMONWEALTH AVENUE
CHESTNUT HILL,MA 02467

Performing Department
GEOLOGY & GEOPHYSICS

Non Technical Summary
NON-TECHNICAL SUMMARY: The aim of this research is to determine the amount of carbon being transferred from the atmosphere to the soil because of CO2 fertilization. CO2 fertilization is the increase in plant growth in response to elevated atmospheric carbon dioxide levels. Increased plant growth may lead in increased soil carbon storage. Knowing how much additional carbon is stored in soil because of CO2 fertilization will lead to more accurate predictions of future CO2 levels and global warming. To see if CO2 enrichment increases soil carbon storage, I have collected a set of unique samples and developed a method for determining the soil carbon CO2 fertilization factor using radiocarbon, d13C, and carbon inventory measurements. The soil carbon CO2 fertilization factor is the fractional change in soil carbon input divided by the fractional change in carbon dioxide level. It is my hope that the techniques used for this research will be applied to other CO2 fertilization experiments and used to evaluate how much carbon might be sequestered in soil by re-vegetating abandoned agricultural land. If a type of vegetation had an unusually high soil carbon CO2 fertilization factor, plantations of this species could be established on abandoned cultivated land to further slow the build-up of atmospheric carbon dioxide levels.

Animal Health Component

85%

Research Effort Categories

Basic

15%

Applied

85%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	0613	1070	50%
102	0110	1060	50%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
0110 - Soil; 0613 - Mixed conifer-broadleaf forests;

Field Of Science
1060 - Biology (whole systems); 1070 - Ecology;

Keywords

biogeochemistry

nutrient cycle

carbon cycle

sequestrants

carbon

soil nutrients

carbon dioxide

fertilization

environmental impact

forest soils

soil plant nutrient relations

plant biology

nutrient accumulation

quantitative analysis

carbon dioxide enrichment

rate determination

measurement

comparative analysis

nitrogen

nutrient availability

carbon isotopes

Goals / Objectives
OBJECTIVES: to measure the difference in mineral-bound soil carbon accumulation rates between forests exposed to current ambient atmospheric carbon dioxide levels and forests exposed to elevated carbon dioxide levels; to determine the quantitative significance of the differences in soil carbon accumulation rates between the elevated and ambient rings; measuring changes in soil nitrogen inventories; to see if nitrogen availability influences the CO2 fertilization response; to determine the soil carbon CO2 fertilization factor using radiocarbon, d13C, and carbon inventory measurements.

Project Methods
APPROACH: Soil carbon and radiocarbon measurements will be used to determine the turnover time and inventory of soil carbon for a Free-Air CO2 Enrichment (FACE) experiment. These measurements will be used to derive the soil carbon CO2 fertilization factor. I will use this soil carbon CO2 fertilization factor to calculate the increase in carbon storage for this closed-canopy ecosystem using the contemporary increase in atmospheric CO2.

Progress 10/01/02 to 09/30/03

Outputs
99% of the analytical work is complete. 3 papers for this project were published in 2003. Segal, M.G. & K.G. Harrison. 2003. Soil carbon storage in abandoned agricultural land in the Duke Forest. In Changing land use and terrestrial carbon storage, Global Discovery Press, 34-53. Harrison, K.G. M.G. Segal & M.H. Hoskins. 2003. Assessing the impact of tillage methods on soil carbon levels and crop yield. In Changing land use and terrestrial carbon storage, Global Discovery Press, 22-33. Mahoney, R. J. & K.G. Harrison. 2003. Procedure for determining soil-bound organic carbon and nitrogen. In Changing land use and terrestrial carbon storage, Global Discovery Press, 1-21. 2 papers for this project are in press. Harrison, K.G., R.J. Norby, W.M. Post, E.L. Chapp & A.L. Kafka. 2004. Measuring the transfer of carbon from the atmosphere to soil by CO2 fertilization via belowground plant carbon inputs in a white oak CO2 enrichment experiment. Earth Interactions, in press. Harrison, K.G. 2004. The soil carbon CO2 fertilization factor: The measure of an ecosystem's capacity to increase soil carbon storage in response to elevated CO2 levels. G-Cubed (Geochemistry, Geophysics, Geosystems), in press. 1 paper for this project has been submitted. Reimer, A.L., M.K. Redfearn & K.G. Harrison. Forest-floor litter, carbon, and nitrogen accumulation due to CO2 enrichment. Submitted to Plant and Soil. 4 more papers for this project will be completed this summer.

Impacts
Balance the global carbon budget.

Publications

• Segal, M.G. & K.G. Harrison. 2003. Soil carbon storage in abandoned agricultural land in the Duke Forest. In Changing land use and terrestrial carbon storage, Global Discovery Press, 34-53.
• Harrison, K.G. M.G. Segal & M.H. Hoskins. 2003. Assessing the impact of tillage methods on soil carbon levels and crop yield. In Changing land use and terrestrial carbon storage, Global Discovery Press, 22-33.
• Mahoney, R. J. & K.G. Harrison. 2003. Procedure for determining soil-bound organic carbon and nitrogen. In Changing land use and terrestrial carbon storage, Global Discovery Press, 1-21.
• Harrison, K.G., R.J. Norby, W.M. Post, E.L. Chapp & A.L. Kafka. 2004. Measuring the transfer of carbon from the atmosphere to soil by CO2 fertilization via belowground plant carbon inputs in a white oak CO2 enrichment experiment. Earth Interactions, in press.
• Harrison, K.G. 2004. The soil carbon CO2 fertilization factor: The measure of an ecosystem's capacity to increase soil carbon storage in response to elevated CO2 levels. G-Cubed (Geochemistry, Geophysics, Geosystems), in press.
• Reimer, A.L., M.K. Redfearn & K.G. Harrison. 2004 Forest-floor litter, carbon, and nitrogen accumulation due to CO2 enrichment. Submitted to Plant and Soil.

Progress 10/01/01 to 09/30/02

Outputs
I have completed analyzing the FACE soil samples for carbon, nitrogen, d13C and radiocarbon. I have submitted the carbon inventory results for publication and presented the results at two conferences: AGU Spring and USDA sequestration conference in Raleigh. I am working on the radiocarbon paper at present. To date, the data suggest that carbon dioxide is increasing soil carbon inventories enough to balance the global carbon budget.

Impacts
My research will show how abandoned agricultural land can be used to remove carbon dioxide from the atmosphere and quantify the amount of carbon stored in soil because of CO2 fertilization.

Publications

• Harrison, K. G., R. J. Heumann & A. L. Kafka. 2002a. Evidence for increased soil carbon and nitrogen accumulation under CO2 enrichment. Submitted to Geophysical Research Letters. www2.bc.edu/~harriskg/2002a.pdf