ORNL and LANL scientists are exploring the large potential of the earth’s soils to sequester carbon, with estimates claiming that new land-use practices could greatly reduce U.S. carbon emissions by as much as 25 percent.
But exactly which practices are the most effective is still unclear, and a research paper published in the Soil Science Society of America Journal shines some light on this topic by introducing an easy-to-use field-portable approach to measure the carbon content of soils.
“This is a tool one could use to measure changes in soil carbon over time and try to establish whether soil carbon stocks are increasing or decreasing as a result of land-use practices,” said lead author Madhavi Martin of ORNL’s Environmental Sciences Division. “Although it is possible to measure these properties in the laboratory, the simplicity and portability of the device allow researchers exponentially greater flexibility to conduct their investigations.”
The paper describes the adaptation of Laser Induced Breakdown Spectroscopy, or LIBS, a technique that once made Martin something of a celebrity when she used it confirm the common origin of two separate pieces of firewood – evidence that eventually led to a confession in a 2006 Texas murder case. LIBS works by measuring the light emitted when a small portion of the sample is annihilated with a laser pulse, a flash that provides an elemental fingerprint of virtually any substance under examination.
The challenge for the authors was configuring the experimental design to ensure accurate measurements of carbon regardless of soil characteristics. To accomplish this, the authors acquired a varied set of soil samples with different sand, silt and clay compositions from the Natural Resources Conservation Service and tested them against numerous laser wavelength and energies.
“We found that LIBS is a promising technique that provides a robust method for the sampling of soil carbon, relying solely on technology that can be taken to the field,” Martin said. “Crop scientists, carbon managers and instrument developers should find these results encouraging.”
With new techniques such as LIBS to assist them, researchers hope they can eventually identify the agricultural practices that provide the maximum benefits to farmers and the climate alike. Intensive farming is a double-edged sword as it can greatly enhance crop production in many areas of the country. Often, however, this comes at the expense of soil health in addition to accelerating the rate of climate change, according to the researchers.
Twice as much carbon is stored in the soils of the world as in the atmosphere, thanks to centuries of decomposition of plants and other organic matter. Fertile (high carbon content) soil is necessary for the growth of large healthy crops. However, fertile soil is also a favorite target of naturally occurring bacteria.
Fortunately for farmers and plants, the majority of carbon beneath our feet is physically protected from bacteria in what scientists call soil aggregates. A large portion of that carbon is concentrated near the earth’s surface and therefore highly vulnerable to changes in land use. When a soil’s aggregate structure is disturbed, such as through intensive farming, the organic matter it protects becomes accessible to soil microorganisms that use it as an energy source, releasing the stored carbon back into the atmosphere as the greenhouse gas CO2.
“Disruption of soil structure is estimated to contribute to a 50 percent loss of soil carbon,” said Chuck Garten, a soil scientist at ORNL. “When the microstructure of the soil is disturbed, it breaks down the aggregates allowing large losses of soil carbon as a result of microbial decomposition.”
This lesson was learned the hard way by many American farmers when pressure for production leads to serious soil degradation through erosion and nutrient losses. Intense farming by pioneer farmers in the first 30 years of settlement depleted the organic matter in the U.S. Great Plains by more than 50 percent with soil productivity falling more than 70 percent during the same period.
Eventually, better agricultural practices were adopted and production recovered. Still, grassland and forest soils continue to lose 20 percent to 50 percent of their original carbon content within the first 40 years of cultivation while tropical climates that practice shifting cultivation or slash and burn agriculture can lose their fertility within two to three years. Farmers make up for the loss by simply moving to new fields or replenishing carbon stocks with the use of manures and other organic wastes.
The research at Oak Ridge National Laboratory was funded by the Department of Energy’s Office of Science, Biological and Environmental Research.
UT-Battelle manages Oak Ridge National Laboratory for the Department of Energy.
Ron Walli | Newswise Science News
Faba fix for corn's nitrogen need
11.04.2018 | American Society of Agronomy
Wheat research discovery yields genetic secrets that could shape future crops
09.04.2018 | John Innes Centre
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy