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
Kakao in Monokultur verträgt Trockenheit besser als Kakao in Mischsystemen
18.09.2017 | Georg-August-Universität Göttingen
Ultrasound sensors make forage harvesters more reliable
28.08.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP
Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.
Graphene is up to the job
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
26.09.2017 | Life Sciences
26.09.2017 | Physics and Astronomy
26.09.2017 | Information Technology