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United States Department of Agriculture

Agricultural Research Service

Research Project: SOIL CARBON CYCLING, TRACE GAS EMISSION, TILLAGE AND CROP RESIDUE MANAGEMENT

Location: Soil Management Research

2008 Annual Report


1a.Objectives (from AD-416)
1. Determine how crop, biomass and soil management practices alter the rate at which carbon and nitrogen are stored in soil or released as greenhouse gas emissions to develop economically viable practices that enhance storage and minimize emissions particularly in the cool, wet, glacial-till soils in the north Central United States. 2. Evaluate impacts of global environmental changes on traditional, biofuel and alternative crops.


1b.Approach (from AD-416)
Carbon cycling will be conducted as part of a national monitoring effort (GRACEnet). Soil physical, chemical and biological factors, and crop inputs will be monitored over time. Established long-term field experiments will be continued to assess impact of tillage method on carbon storage, trace gas emission and economic yield. The active, transitional and passive pools will be assessed in the tillage treatments to determine the rate and direction of change in the various pools. On-farm research is comparing the impact of high manure application on gas exchange monitored by eddy covariance and monitoring the nutrient content of tile water samples. Economic analysis will be conducted to evaluate the economic returns for the different residue removal/tillage combinations. Field experiments will be conducted to obtain plant parameters from a range of species and management systems. The plant data will be integrated with the soil carbon data to statistically model dynamics of C inputs and subsequent changes in carbon pools. Plant information will be collected from growth chamber and/or greenhouse experiments utilizing controlled conditions to mimic desired environmental stresses.


4.Accomplishments
1. Agricultural Greenhouse Gas Emissions and mitigation strategies Agriculture contributes to greenhouse gas emission, which traps heat in the atmosphere. However, modification of agricultural management has the potential to shift agriculture from a net source of greenhouse gas to a net sink; thereby, agriculture could play a role in mitigating global climate change. Based on a literature synthesis current agricultural contributions to greenhouse gas emissions and C sequestration were summarized and strategies for how agriculture might lessen its burden on the greenhouse effect proposed. This information will educate scientists, producers and the general public including policy-makers of strategies that allow agriculture to help mitigate greenhouse gas emission, and lessen the risk of disastrous global climate change. NP 204, Component I. Component I: Carbon Cycle and Carbon Storage Component, Problem statements: Cropping System and Tillage, organic carbon transformations, interactions of carbon and nitrogen cycles and to Component II Trace Gases Component Problem Areas: Cropping systems and Component. This contributes to the GRACEnet cross-location project.

2. Greenhouse gas emissions affected by tillage, manure and cover crops. The amount of greenhouse gas emissions (carbon dioxide) differs among contrasting management systems with greatest flux from manure and cover crop treatments as measured by the eddy covariance system. Preliminary on-farm trials suggest beneficial effects of manure on the carbon and water balances relative to inorganic fertilizers. The incorporation of a winter rye cover crop in a corn silage system can take up significant amounts of carbon in the biomass to protect the soil surface from raindrop impact and will temporarily tie up significant amounts of nitrogen and prevent it from leaching through the tile drains. The economic benefits of the cover crops can be positive or negative depending on the current rainfall pattern and amounts in a given growing season, suggesting the need for improved and timely cover crop management decisions to minimize agriculture's impact on environmental quality. NP 204 Component I: Carbon cycle and carbon storage.

3. Tillage and wind effects on soil CO2 concentrations in muck soils. Rising atmospheric carbon dioxide (CO2) concentrations from agricultural activities has prompted the need to quantify greenhouse gas emissions to better understand carbon (C) cycling and its role in environmental quality. This work determined the effect of no-tillage, deep plowing and wind speeds on the soil CO2 concentration in muck soils of the Florida Everglades, which was published in a peer-reviewed journal. Several key points were noted.
1)Soil CO2 flux was temporally dynamic and independent of barometric pressure fluctuations;.
2)Tillage increased soil air permeability, which enabled wind to more effectively draw CO2 out of the soil. Thus, higher wind speeds during mid-day resulted in a more rapid loss of CO2 from the deep plowed than from the no till (NT) plots. This information will assist farmers, scientists, engineers and policymakers in developing improved tillage methods to minimize the gaseous loss and to improve soil carbon management. NP 204 Component I: Carbon cycle and carbon storage.


5.Significant Activities that Support Special Target Populations
None.


6.Technology Transfer

Number of Non-Peer Reviewed Presentations and Proceedings5

Review Publications
Johnson, J.M., Franzluebbers, A.J., Lachnicht Weyers, S.L., Reicosky, D.C. 2007. Agricultural Opportunities to Mitigate Greenhouse Gas Emissions. Environmental Pollution. 150:107-124.

La Scala, Jr., N., Lopes, A., Spokas, K.A., Bolonhezi, D., Archer, D.W., Reicosky, D.C. 2008. Short-term temporal changes of soil carbon losses after tillage described by a first-order decay model. Soil & Tillage Research. 99:108-118.

Reicosky, D.C., Gesch, R.W., Wagner, S.W., Gilbert, R.A., Wente, C.D., Morris, D.R. 2008. Tillage and wind effects on soil CO2 concentrations in muck soils. Soil and Tillage Research. 99:221-231.

Wilhelm, W.W., Johnson, J.M., Karlen, D.L., Lightle, D. 2007. Corn Stover to Sustain Organic Carbon Further Constrains Biomass Supply. Agronomy Journal. 99:1665-1667.

Reicosky, D.C. 2008. Carbon sequestration and environmental benefits from no-till systems. In: Goddard, T. et al., editors. No-till Farming Systems. Special Publication No. 3. Bangkok, Thailand: World Association of Soil and Water Conservation. p. 43-58.

Last Modified: 4/19/2014
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