This information is vital for examining changes in cropland production and management techniques and could play an even bigger role as more land is devoted to bioenergy crops, said Oak Ridge National Laboratory's Tristram West, lead author of a paper published on line in the Journal of Environmental Quality.
"By looking at changes in energy consumption and CO2 emissions that take place with conventional and alternative crop production, we can do a better job of measuring the effects of various carbon sequestration strategies," West said. "This information can also contribute to future policy directions for energy use and agricultural production."
West and co-authors at the University of Tennessee, Kansas State University and ORNL looked at data from 1990 to 2004 and calculated energy consumption and CO2 emissions from fossil fuel combustion associated with U.S. cropland production. For this project they used a combination of independent survey data, national inventory data, established energy consumption parameters for field-scale operation budgets and CO2 emissions coefficients.
The researchers used a number of other resources, including the University of Tennessee's Agriculture Budget System, which consists of more than 3,500 conventional and alternative management practices for corn, soybean, wheat, sorghum, barley, oat, rice, cotton and hay. As of 2006 these nine crops accounted for about 96 percent of total crop production in the U.S.
On-site energy use and emissions result from fossil fuel combustion that occurs on the farm. Off-site energy and emissions result from fossil fuel combustion linked to the production and transport of fertilizers, pesticides and seeds. Off-site emissions also include those from power plants that produce electricity used on the farm.
The researchers were particularly interested in variations in energy consumption that occur when field management strategies change. For example, they found that the adoption of reduced tillage practices from 1990 to 2004 resulted in a net fossil emissions reduction of 8.8 million metric tons of CO2. Above-average rainfall in 1993 caused fields to be flooded in Minnesota, Iowa, Missouri, Kansas and Nebraska. As a result, farmers planted fewer crops and CO2 emissions fell.
"Changes in agriculture policy and extreme weather events influence agricultural land use and subsequent energy consumption and CO2 emissions associated with crop production," West said.
Looking at the nation's total CO2 picture, less than 2 percent of the 6,090 million metric tons is the result of farming activities. Electricity generation is the largest source of emissions followed by transportation, industrial, residential and commercial use.
Among the findings was that energy use and emissions do not always change proportionately with the area of cropland in production. Instead, they vary by crop and management practices. Researchers also found that on-site emissions can be reduced by half for some crops if farmers change from conventional tillage to no-till.
This study did not take into account nitrogen oxide emissions from the use of nitrogen fertilizers. It did, however, consider CO2 emissions from the production of fertilizer. Those are included in the off-site estimates.
Another key aspect of the project is that the data provide a spatial distribution of carbon flux, which will allow researchers to compare this information to atmospheric measurements that are part of the North American Carbon Program (http://www.nacarbon.org/nacp/).
The authors conclude the paper by saying, "Through continued analyses, we will have a better understanding of how carbon dynamics in U.S. agriculture are being impacted by changes in land cover and land management."
The research was funded by the Department of Energy's biomass program, within the Office of Energy Efficiency and Renewable Energy and the Office of Biological and Environmental Research within the Office of Science. Additional resources were contributed by NASA. Energy and emissions data from U.S. cropland production are archived with the Carbon Dioxide Information Analysis Center (http://cdiac.ornl.gov/carbonmanagement/cropfossilemissions).
UT-Battelle manages Oak Ridge National Laboratory for the Department of Energy. The Journal of Environmental Quality (http://jeq.scijournals.org) is a peer-reviewed, international journal of environmental quality in natural and agricultural ecosystems published six times a year by the American Society of Agronomy, Crop Science Society of America and the Soil Science Society of America.
Ron Walli | EurekAlert!
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology