SOIL
CARBON AND CLIMATE CHANGE NEWS
From
Consortium for Agricultural Soils
Mitigation of Greenhouse Gases (CASMGS)
http://soilcarboncenter.k-state.edu
Charles W. Rice, K-State Department of
Agronomy, National CASMGS Director
(785) 532-7217 cwrice@ksu.edu
Scott Staggenborg, K-State Department of
Agronomy (785) 532-7214 sstaggen@ksu.edu
Steve Watson, CASMGS Communications (785)
532-7105 swatson@ksu.edu
December 14, 2007
No. 60
Science and Research:
* LIBS: A New Rapid Method For Measuring Soil Carbon
International:
*
Summary Of IPCC Synthesis Report On Climate Change
**********
libs:
a NEW rapid method
for
measuring soil carbon
As global warming becomes a
more important issue on the domestic and world stage, analyzing greenhouse
gases with consistency and accuracy becomes critical to designing policies and
programs for mitigation and adaptation. With increasing international concern
about greenhouse gases and global warming, scientists have sought better and
more cost-effective approaches for measuring changes in the amount of
land-based carbon, much of which is located in soils.
Laser-Induced Breakdown
Spectroscopy (LIBS) is a device that is being tested to measure soil carbon. If
used in a carbon credit program, it could reduce the cost of measuring soil
carbon levels.
Currently, the most common
method for measuring soil carbon is the dry-combustion method. This involves
taking a soil sample from the field and processing it in the lab. The sample is
air-dried, sieved (to separate out the large organic particles), ground,
weighted, and dry-combusted to measure the carbon.
Dry combustion is
time-consuming and expensive, so scientists have been formulating other, more
efficient ways to measure soil carbon. In addition to LIBS, researchers are
examining inelastic neutron scattering (INS) and diffuse reflectance IR
spectroscopy in the near-infrared (NIR) and mid-infrared (MIR) wavelengths.
The current LIBS machine was
created by researchers at the Los Alamos National Laboratory in 2001, but the
underlying technology is not new. Scientists have considered using the same
technology to study the surfaces of planets and moons.
The most beneficial aspect
of LIBS is its time- and money-saving potential. LIBS can issue an analysis of
a soil sample in less than one minute, according to Cesar Izaurralde, of the
Joint Global Change Research Institute and Pacific Northwest National Labs.
Because labor and time are costly, LIBS would reduce the cost of soil carbon
assessment. If used in a carbon credit program, it would in turn reduce the
cost of monitoring soil carbon levels, potentially leaving more money for the
landowner or producer. In addition, this method can be done directly in the
field.
How it works: LIBS comes in
portable or lab versions. Scientists take a soil sample, dry it, then use a
compressor to pack it tightly into a “dime,” or a slim cylinder about the size
of a half-dollar coin. The dimes are then placed on a track connected to the
machine. A laser is shot at the sample, leaving a tiny dotted line. This is
done five times for each sample, and an average reading is taken.
The heat from the laser
excites the chemical bonds in the soil. Every molecular bond breaks, and the
matter is reduced to its component elements, such as carbon, oxygen, and
potassium. The emitted light from each element is sent into a spectrometer, and
creates a wavelength graph. Each element has a unique wavelength that does not
vary, so by analyzing the graph, scientists can determine the type and quantity
of each element in the sample.
LIBS is currently being
tested at
To get precise carbon
measurements from LIBS readings, Dr. Wang uses site-specific calibration curves
based on data derived from the dry combustion process. The lab data from a
specific soil are correlated with measurements from LIBS. This helps determine
the accuracy of the new technology.
Several factors affect
carbon measurements taken by LIBS, such as moisture, mineralogy, the particle
size and density of the soil, and organic matter levels in the soil.
One of the dilemmas for LIBS
is how to account for undecomposed organic matter, such as pieces of crop
residue. In dry combustion, plant material is sieved and finely ground before
analysis. In LIBS, it is left heterogeneously in the sample. Wang has created a
homogeneous, artificial soil core that contains no visible plant residue and
places it on a track next to a natural soil that contains visible plant matter.
She shoots the laser straight down the track, first at the homogenous soil,
then at the natural soil, to see what effect the undecomposed plant residue has
on the measurements.
Also, Dr. Wang has
discovered that the specific type of carbon compounds in the soil make a
difference, and affect the LIBS analysis differently. This is because of the
types of bonds the compounds are composed of. For example, organic carbon’s
molecular structure has more complex bonds than inorganic carbon. LIBS reads
them differently. This occurs with all elements, and is not exclusive to
carbon.
The next step is to develop
a standard calibration for LIBS, Dr. Wang says. Woodland soil from
By including all of the
chemical elements in the calibration curve, Dr. Wang says a standard
calibration can be achieved. That way, factors such as moisture, soil type,
soil density, and organic matter wouldn’t interfere.
Another benefit of using
LIBS, besides offering quick measuring time, is that it measures other elements
in the soil at the same time it measures carbon. This can assist scientists in
determining overall soil fertility.
-- Katie Starzec, CASMGS
Communications,
The portable LIBS being
evaluated at Los Alamos National Laboratory.
**********
Summary Of IPCC Synthesis Report
On Climate Change
The Intergovernmental Panel
on Climate Change released its fourth and final report November 17, 2007.
Titled “Climate Change 2007,” the report explains the climatic changes caused
by global warming, why it may be happening, how it may affect the future, and
what people can do to curb the effects.
The AR4 (Assessment Report
4) Synthesis Report summarizes the research of the three IPCC working groups:
“The Physical Science Basis,” “Impacts, Adaptations and Vulnerability,” and
“Mitigation of Climate Change.”
The following facts and
opinions come from the AR4 Synthesis Report Summary for Policy Makers, which
can be found at http://www.ipcc.ch/.
The IPCC states that the
atmosphere is without a doubt getting warmer.
Eleven of the past 12 years
have been the warmest on record since 1850. Increases in air and ocean
temperatures, widespread melting of snow and ice, and rising sea levels are a
direct result of higher temperatures. Evidence shows that intense tropical
cyclone activity has increased in the
Flowers blooming early,
animals migrating toward the poles, and weakening permafrost illustrate that
many natural systems are being affected by changes in climate. More than 89
percent of all physical and biological systems that the IPCC studied are
changing due to an increase in temperatures.
Also, there is speculation
that fire, pests, infectious diseases, and allergenic pollen levels are being
impacted by climate change.
Evidence shows that humans
have most likely caused the increase in temperatures.
Fossil fuel use,
agriculture, and land-use changes have increased the amount of greenhouse gases
in the air, causing warm sun rays to become trapped in the atmosphere.
Human influences have:
• very
likely contributed to sea level rise during the latter half of the 20th
century.
• likely
contributed to changes in wind patterns, affecting extra-tropical storm
tracks and temperature patterns.
• likely
increased temperatures of extreme hot nights, cold nights, and cold days.
• more
likely than not increased risk of heat waves, areas affected by drought
since the 1970s, and frequency of heavy precipitation events.
Natural forces from the sun and volcanoes, without
any human impact, would likely have cooled the earth in the past 50 years. Models
show that because of certain responses of nature, at least some of the warming
is anthropogenic; the IPCC says it is very unlikely that nature would do this
on its own.
Impacts will become more severe as temperatures
increase.
Global
GHG emissions due to human activities have grown since pre-industrial times,
with an increase of 70 percent between 1970 and 2004. The IPCC projects a 25-90 percent increase in
greenhouse gas emissions between the years 2000 and 2030. Some impacts may be
irreversible.
With an increase in temperature, coastal flooding and
damage would occur more frequently. More water would be available in high
latitudes and tropics and less available in mid-, semi- and low-latitudes. Some
agriculture yields may increase in mid- to high latitudes and colder
environments, while yields would decrease in low latitudes and warmer areas.
If temperature increases exceed 3.5 degrees Celsius,
or 6.3 degrees Fahrenheit, 40-70 percent of all identified species will become
extinct.
Melting from ice sheets could inundate coastal areas,
islands, and other low-lying areas over the next millennium. A rise in sea
level is inevitable, and may occur during this century.
Effects on human health include an increase in
malnutrition, infectious diseases, and deaths due to drought, heat waves and
floods. Evidence shows that specific groups such as the poor and elderly are
the most vulnerable, and areas with weak economies and limited access to
resources will be most affected.
If used together, mitigation and adaptation are the
best solution.
In the long term, it is likely that human systems
will not be able to adapt if climate change is not mitigated. This timeframe
varies from region to region.
The IPCC has high confidence that neither adaptation
nor mitigation alone will be the best solution, but they can complement each
other and reduce the effects of climate change when used together.
Adaptations include:
·
water
conservation through rainwater harvesting and better irrigation methods
·
crop relocation
and improved soil erosion control
·
creating
marshlands as a buffer to sea level rise and relocating coastal settlements
·
heat-health
action plans and emergency assistance
·
climate
sensitive disease surveillance and control
·
Examples of mitigation techniques:
·
improving crop
and range land management to increase soil carbon storage
·
improving
nitrogen fertilizer management to reduce nitrous oxide emissions
·
reforestation/forest
management
·
creating
second-generation biofuels and high-efficiency aircraft
·
using nuclear
power, renewable energy, and more fuel-efficient vehicles
·
creating markets
for low emissions technologies
·
recycling and
minimizing waste
Governments can create the incentive for mitigation
through many avenues, and the IPCC strongly believes that changes in lifestyle,
behavior patterns, and management practices can contribute to climate change
mitigation across all sectors.
-- Katie Starzec, CASMGS
Communications,
MEETINGS OF INTEREST
Dec. 17-18, 2007
CASMGS Forum: Agriculture's
Role in the New Carbon Economy
http://soilcarboncenter.k-state.edu/Fall_Forum_CASMGS.html
**********
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