From Kansas State University's:

Consortium for Agricultural Soils Mitigation of Greenhouse Gases (CASMGS)


Charles W. Rice, K-State Department of Agronomy, National CASMGS Director

(785) 532-7217

Scott Staggenborg, K-State Department of Agronomy (785) 532-7214

Steve Watson, CASMGS Communications (785) 532-7105



December 14, 2007

No. 60


Science and Research:

* LIBS: A New Rapid Method For Measuring Soil Carbon



* 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 Kansas State University because of the campus’ unique grass- and cropland sites. Post-doctoral research associate Autumn Wang is trying to find ways to make LIBS as accurate as the dry-combustion method. Though the speedy analysis makes the machine attractive, it has a precision of 4-5 percent and an accuracy of only 3-14 percent, according to Izaurralde.


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 New Mexico is very different than agricultural soil from Colorado. Because soil type and structure change from area to area, LIBS needs to be calibrated every time it takes measurements from different soils to account for variations in the soil.


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, Kansas State University




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


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 North Atlantic since the 1970s, and it is likely that heat waves and heavy rains are occurring more frequently.


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, Kansas State University






Dec. 17-18, 2007

CASMGS Forum: Agriculture's Role in the New Carbon Economy

Manhattan, Kansas







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