SOIL CARBON AND CLIMATE CHANGE NEWS
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 firstname.lastname@example.org
Scott Staggenborg, K-State Department of Agronomy (785) 532-7214 email@example.com
Steve Watson, CASMGS Communications (785) 532-7105 firstname.lastname@example.org
February 22, 2011
* Evaluating Long-Term Impacts of Harvesting Crop Residues on Soil Quality
* Small Grain Residue Management Effects on Soil Organic Carbon: A Literature Review
* Implications for Soil Properties of Removing Cereal Straw
* Forages, cover crops and related shoot and root additions in no-till rotations to C sequestration in a subtropical Ferralsol
* Life Cycle Analysis Trend Boosted by Walmart
* 2010 Tied for Warmest Year on Record, NASA Research Finds
* Chicago Climate Exchange Ends Cap-and-Trade Operations
* Ag Secretary Vilsack Announces New Steps to Meet the Challenge of Climate Change
* Alberta Province Climate Change Program Includes Agricultural Carbon Credits
* Adapting Agriculture to Climate Change: New Global Search to Save Endangered Crop Wild Relatives
Evaluating Long-Term Impacts of
Harvesting Crop Residues on Soil Quality
A special section in the January 2011 issue of Agronomy Journal contains several papers from a symposium titled “Residue Removal and Soil Quality—Findings from Long-Term Research Plots.” Presentations at this symposium examined residue removal impacts in the context of various management practices including crop rotation, tillage, applied fertilizer, and irrigation. The seven papers from the symposium that are published here primarily focus on residue harvest and input effects on soil organic carbon (SOC) over time.
David R. Huggins, USDA-ARS in Pullman, Washington, and colleagues provide the following introduction and summary of these papers:
* Powlson et al. reviewed 14 long-term studies from Europe, Australia, and Canada that examined straw removal effects on SOC. They concluded that residue removal resulted in small decreases in SOC; however, these small changes could have disproportionately large negative effects on microbial activity and related soil physical properties such as aggregate stability. Powlson et al. (2011) cautioned against annual removal of straw and recommended that studies be coupled to areas where residue harvest is being considered due to the site-specific nature of soil response to straw removal.
* Machado evaluated long-term dryland cropping system studies located near Pendleton, OR, with respect to effects on SOC. Here, removal of crop residues in winter wheat–summer fallow rotations which predominate in the region will increase SOC depletion, whereas continuous cropping, particularly in combination with no-tillage could maintain adequate SOC and soil productivity. Machado concluded that residue harvest may be sustainable if the wheat–fallow system was replaced with continuous cropping and no-tillage.
* Nafziger and Dunker reported on the long-term SOC trends under different crop rotation and fertilizer treatments at the University of Illinois Morrow Plots. Significant SOC decline occurred during the first half of the 20th century under annual residue removal with no fertilizer additions. Since then, however, SOC response to various treatments including residue removal have been inconsistent, although it is apparent that adequate nutrient levels are important for maintaining SOC.
* Miles and Brown found that long-term plots at the University of Missouri Sanborn Field also showed significant SOC decline with treatments that removed residues; however, retaining field residues was positively related to SOC.
* Gollany et al. evaluated five long-term field experiments in North America and simulated SOC dynamics under a wide range of biophysical factors with the CQESTR model. They concluded that increasing soil C inputs through manure additions and/or crop intensification as well as reducing tillage were important strategies for mitigating residue harvest impacts on SOC levels.
* Tarkalson et al. reviewed small grain residue management effects on SOC and specifically on SOC changes for six irrigation studies where wheat straw was removed or retained. They reported that SOC either increased or remained constant when wheat residues were removed and hypothesized that below-ground biomass production was important for maintaining or increasing SOC under irrigation. Tarkalson et al. point out that irrigated cropping systems in the Pacific Northwest and elsewhere tend to be diversified and include crops such as alfalfa, potato, and sugarbeet in addition to wheat and corn and that very little data on residue removal effects on SOC are available for these situations.
* Karlen et al. reported on the initiation of a U.S.-based multi-location study to: (i) evaluate the effects of harvesting corn stover on soil quality; (ii) assess potential trade-offs between short-term economic returns to growers harvesting residue and long-term benefits to soil, air, and water from retaining residues; and (iii) develop management strategies that support the sustainable harvest of crop residues. They reviewed issues surrounding the use of corn stover as a bioenergy feedstock and demonstrate the usefulness of the Soil Management Assessment Framework (SMAF) as a tool to monitor and evaluate soil responses to land-use changes associated with the developing biofuel industry. Initial study results included a SMAF analysis that identified SOC as a critical soil indicator with respect to monitoring residue removal effects on soil quality.
Summary and Conclusion: It is clear from the articles in this special section that residue harvest will impact SOC and associated soil properties and that residue removal effects cannot be evaluated in isolation. Factors such as initial site characteristics (e.g., soil, water, air, and wildlife resources), the suite of management practices that comprise the cropping system and the economic returns from residue harvest must be integrated into any analysis and likely trade-offs assessed. This situation shifts evaluation to the farm scale where emphasis should be placed on providing science-based decision aids that growers can practically apply to their unique farms. These might include technologies that measure site-specific residue loads and define threshold levels for residue removal that occur under different management scenarios. Management scenarios should include economic and environmental evaluation of alternative practices that could enable the sustainable harvest of residue feedstocks for a given location and situation.
-- Agronomy Journal, January 2011, Vol. 103 No. 1, p. 230-233
Summaries of two of these papers are below.
Small Grain Residue Management Effects
on Soil Organic Carbon: A Literature Review
In a review of research, D. D. Tarkalson, USDA-ARS North West Irrigation and Soils Research Lab, Kimberly, Idaho, and colleagues investigated the effects of wheat and barley straw removal on soil organic carbon (SOC) in irrigated production systems. The authors then related the results to estimates of the minimum straw carbon inputs required to maintain soil organic carbon (MSC) from rain-fed systems. They found an important difference in the two types of systems.
The abstract states: “Six studies compared SOC changes with time in irrigated systems in which wheat straw was removed or retained. These studies indicated that SOC did not decline when residues were removed. Apparently belowground biomass is supplying C to irrigated soils at a rate sufficient to maintain SOC with time.
“However, under rain-fed systems, returning residue to the soil was required to maintain SOC. Estimates of MSC were obtained from nine rain-fed wheat system studies. Averaged across all rain-fed MSC values, 4.14 Mg more straw per hectare was required to maintain SOC in rain-fed than in irrigated systems. Presently, the rain-fed based MSC values are the best information available to evaluating residue removal effects but caution should be used in applying these in irrigated systems.”
The authors conclude: “The results from this limited number of irrigated studies suggest that rain-fed estimates of MSC will overestimate the MSC in irrigated systems and underestimate the available irrigated straw resources. There is need to evaluate the effect of residue removal on SOC for diverse irrigated systems.”
Source: Agronomy Journal, January 2011, Vol. 103 No. 1, p. 247-252
-- Steve Watson, CASMGS Communications
Implications for Soil Properties
of Removing Cereal Straw
A study by David S. Powlson and colleagues in the Soil Science Department, Rothamsted Research, UK, found that in 25 experiments of 6 to 56 years in duration, there was a trend for soil organic carbon (SOC) and total soil nitrogen (N) content to increase where straw was incorporated annually. However the increases were only significant in six experiments and were <10% in the majority of cases.
The abstract to the article states: “Increases in microbial biomass C or N were always proportionately greater than for SOC or N. In simulations of annual straw incorporation using the RothC model, 90% of the microbial biomass C increase in 100 years was reached within 20 years as biomass C moves toward a new equilibrium value more rapidly than total SOC. Simulations also showed that if straw was removed in 50% of years, SOC and biomass C increases were about 50% of those with annual straw incorporation.”
The authors conclude: “There is considerable evidence that small changes in total SOC have disproportionately large impacts on soil physical properties such as aggregate stability, water infiltration rate, and plow draft and that microbial activity is crucial in the formation of stable aggregates. We conclude that, although changes in SOC resulting from addition or removal of straw are small, it would be unwise to remove straw every year as this is likely to lead to deterioration in soil physical properties. Local assessments are required to determine the frequency of straw removal that is acceptable for soil functioning; this will influence the capacity of bioenergy installations.”
Source: Agronomy Journal, January 2011, Vol. 103 No. 1, p. 279-287
-- Steve Watson, CASMGS Communications
Forages, cover crops and related shoot and root additions in no-till rotations to C sequestration in a subtropical Ferralsol
A study by Nicolas Zendonadi dos Santos, at the Universidade Federal do Paraná in Brazil, and colleagues examined the relative contributions of shoots and roots to soil organic carbon with different cropping systems.
The abstract states:
The objectives of this study were (i) to assess long-term (17 years) contributions of cover crop- or forage-based no-till rotations and their related shoot and root additions to the accumulation of carbon (C) in bulk and in physical fractions of a subtropical Ferralsol (20-cm depth); and (ii) infer if these rotations promote C sequestration and reach an eventual C saturation level in the soil. A wheat-soybean succession was the baseline system. The soil under alfalfa every three years with maize had the highest C accumulation (0.44 Mg C per hectare per year). The bi-annual rotation of ryegrass–maize–ryegrass–soybean had a soil C sequestration of 0.32 Mg C per hectare per year. Among the two bi-annual cover crop-based rotations, the vetch-maize–wheat–soybean rotation added 7.58 Mg C per hectare per year as shoot plus root and sequestered 0.28 Mg C per hectare per year. The counterpart grass-based rotation of oat (winter cover crop)–maize–wheat–soybean sequestered only 0.16 Mg C per hectare per year, although adding 13% more C (8.56 Mg per hectare per year). The vetch legume-based rotation, with a relative conversion factor (RCF) of 0.147, was more efficient in converting biomass C into sequestered soil C than oat grass-based rotation (RCF = 0.057).
Soil C stocks showed a close relationship with root C addition, a poor relationship with total C addition and no relationship with shoot C addition. This suggests a more effective role of root than shoot additions in C accumulation in this no-till soil. Most of the C accumulation took place in the mineral-associated organic matter (71–95%, in the 0–5 cm layer) compared to the particulate organic matter. The asymptotic relationship between root C addition and C stocks in bulk soil and in mineral-associated fraction supports the idea of C saturation. In conclusion, forages or legume cover crops contribute to C sequestration in no-till tropical Ferrasols, and most of this contribution is from roots and stored in the mineral-associated fraction. This combination of soil and rotations can reach an eventual soil C saturation.
* Forage-based contribute more to soil C sequestration than cover crop-based rotations.
* Legume contributes more than grass cover crop to soil C accumulation in no-tillage.
* Soil C accumulation relates better with root than with shoot additions.
* Most of C accumulation in crop rotations occurs in the mineral-associated fraction.
* There is a trend for C saturation due to root additions in no-till soil.
Life Cycle Analysis Trend
Boosted by Walmart
Walmart has taken the bold step of implementing a “Life Cycle Analysis” program for all of its suppliers and their products. A few other companies have also done this, but none anywhere near the size and with the influence of Walmart.
A life cycle assessment, or LCA, is a more comprehensive version of a carbon footprint. Instead of focusing solely on greenhouse gas (GHG) emissions, an LCA also looks at water, waste, conservation of natural resources and additional pollutants. In fact, Walmart is already requiring its top suppliers to fill out a 15-question sustainability survey.
Retailers want to know the "cradle to gate" impact of products - everything that happens from the time someone scoops the natural resources out of the earth to the time the finished goods hit the retailer's warehouse. If all goes as planned, the result will be a “Sustainability Index” tag on every product.
This is a bold move, and a very complex process to complete. Walmart has more than 100,000 global suppliers, and even more individual products. Requiring an LCA on each of these will not be easy. But the company sees the move as something its customers want.
Walmart’s website states:
“Our customers desire products that are more efficient, last longer and perform better. They want to know the product’s entire lifecycle. They want to know the materials in the product are safe, that it is made well and is produced in a responsible way. These desires inspired us to help develop the sustainability index. With this initiative, we are helping create a more transparent supply chain, driving product innovation and ultimately providing our customers with information they need to assess products’ sustainability.”
Walmart is also helping to create a consortium of universities to collaborate with suppliers, retailers, non-governmental organizations, and government officials in this LCA effort. The Sustainability Index Consortium will help develop a global database of information on products’ lifecycles – from raw materials to disposal. Arizona State University and the University of Arkansas will jointly administer the consortium.
For more information, see: http://walmartstores.com/sustainability/9292.aspx
-- Steve Watson, CASMGS Communications
2010 Tied for Warmest Year on Record,
NASA Research Finds
Global surface temperatures in 2010 tied 2005 as the warmest on record, according to an analysis released Jan. 12, 2011 by researchers at NASA's Goddard Institute for Space Studies (GISS) in New York.
The two years differed by less than 0.018 degrees Fahrenheit. The difference is smaller than the uncertainty in comparing the temperatures of recent years, putting them into a statistical tie. In the new analysis, the next warmest years are 1998, 2002, 2003, 2006, 2007 and 2009, which are statistically tied for third warmest year. The GISS records begin in 1880.
The analysis found 2010 approximately 1.34°F warmer than the average global surface temperature from 1951 to 1980. To measure climate change, scientists look at long-term trends. The temperature trend, including data from 2010, shows the climate has warmed by approximately 0.36°F per decade since the late 1970s.
"If the warming trend continues, as is expected, if greenhouse gases continue to increase, the 2010 record will not stand for long," said James Hansen, the director of GISS.
The analysis produced at GISS is compiled from weather data from more than 1000 meteorological stations around the world, satellite observations of sea surface temperature and Antarctic research station measurements. A computer program uses the data to calculate temperature anomalies — the difference between surface temperature in a given month and the average temperature for the same period during 1951 to 1980. This three-decade period acts as a baseline for the analysis.
The resulting temperature record closely matches others independently produced by the Met Office Hadley Centre in the United Kingdom and the National Oceanic and Atmospheric Administration's National Climatic Data Center.
The record temperature in 2010 is particularly noteworthy, because the last half of the year was marked by a transition to strong La Niña conditions, which bring cool sea surface temperatures to the eastern tropical Pacific Ocean.
A chilly spell also struck this winter across northern Europe. The event may have been influenced by the decline of Arctic sea ice and could be linked to warming temperatures at more northern latitudes.
Arctic sea ice acts like a blanket, insulating the atmosphere from the ocean's heat. Take away that blanket, and the heat can escape into the atmosphere, increasing local surface temperatures. Regions in northeast Canada were more than 18 degrees warmer than normal in December.
The loss of sea ice may also be driving Arctic air into the middle latitudes. Winter weather patterns are notoriously chaotic, and the GISS analysis finds seven of the last 10 European winters warmer than the average from 1951 to 1980. The unusual cold in the past two winters has caused scientists to begin to speculate about a potential connection to sea ice changes.
"One possibility is that the heat source due to open water in Hudson Bay affected Arctic wind patterns, with a seesaw pattern that has Arctic air downstream pouring into Europe," Hansen said.
For more details, see: www.giss.nasa.gov/research/news/20110112/
Chicago Climate Exchange ends
The Chicago Climate Exchange (CCX) was launched in 2003 as a voluntary greenhouse gas (GHG) emission cap and trade scheme located in North America. The nation's first carbon emissions cap and trade exchange has now ended.
The second commitment period for member companies of the Chicago Climate Exchange ended as of Dec. 31, 2010, and there will be no new cycle. CCX’s sister institutions, the European Climate Exchange and the Chicago Climate Futures Exchange, will continue.
In the U.S., there is a mandatory greenhouse gas cap-and-trade program operating in 10 northeastern states through the Regional Greenhouse Gas Initiative (RGGI). And California is gearing up for a mandatory greenhouse gas cap-and-trade system for 2012. The Western Climate Initiative (WCI), of which California is a member, is a coalition of certain western U.S. states and Canadian provinces, but the WCI is in a bit of flux at the moment. Currently, the only cap-and-trade program making solid progress among WCI members in the U.S. is in California.
The credits on the CCX once traded as high as $7.50 per metric ton of CO2-equivalent emissions, but the exchange trading price was just 5-10 cents in open exchange spot trading when the cap-and-trade program ended.
At one time there were 450 members of the exchange, including power companies, manufacturers, cities, and universities. CCX officials calculate the program resulted in emissions reductions totaling nearly 700 million metric tons of carbon dioxide since 2003, equivalent to taking 140 million cars off the road for a year. Reductions in industrial emission accounted for 88 percent of those cuts, while the remaining 12 percent came from so-called offset projects, such as tree planting and agricultural soil carbon sequestration.
The CCX is not entirely closed, however. CCX will continue to operate a registry for carbon offset programs, which presumably would be helpful to those seeking to make voluntary emission reductions. And there will continue to be carbon trading on the Chicago Climate Futures Exchange (CCFE)—a platform for both voluntary and small, regional mandatory climate programs like the one adopted in the northeastern United States. IntercontinentalExchange, the Atlanta-based owner of CCX, says it will continue to operate both the Chicago Climate Futures Exchange and its much larger and more profitable European Climate Exchange.
Other voluntary greenhouse gas offset programs are still operating in the U.S. The Climate Action Reserve (CAR) offers U.S.-based credits. The Voluntary Carbon Standard and the Gold Standard are other programs with significant participation. And there are a number of smaller niche programs.
A good discussion and comparison of current voluntary offset systems, mandatory offset systems, and more can be found at the Carbon Offset Research & Education web site at: http://www.co2offsetresearch.org/index.html
There are other U.S.-based voluntary registry programs, too, in addition to the CCX Registry. By far the largest organizational program still in operation is The Climate Registry (http://www.theclimateregistry.org/).
Information on the current operations of the CCX can be found on its website at:
-- Steve Watson, CASMGS Communications
Ag Secretary Vilsack Announces New Steps
To Meet The Challenge Of Climate Change
Calling it "one of the
greatest threats facing our planet," Agriculture Secretary Tom Vilsack today on
December 9, 2010 that USDA is taking action to meet the challenge of climate
change. Speaking at the recent United Nations Climate Change Conference in
Cancun, the Secretary said USDA continues to take steps to reduce greenhouse gas
emissions "by helping farmers, ranchers and forest landowners to be even better
Vilsack said USDA will demonstrate ways landowners can reduce greenhouse gas emissions and increase carbon sequestration while improving their financial bottom line. The effort includes providing opportunities to leverage private sector demand for greenhouse gas mitigation services, evaluating how emerging greenhouse gas markets can work in concert with USDA programs to protect the environment, and building capacity within USDA to understand voluntary greenhouse gas markets and to explore improved approaches for greenhouse gas accounting systems.
Among the steps announced, Vilsack said USDA's Natural Resources Conservation Service (NRCS) will provide $15 million in Conservation Innovation Grant funds and other assistance to support large-scale demonstration projects to accelerate the adoption of new approaches to reduce greenhouse gas (GHG) emissions and promote carbon sequestration on private lands. As part of this, NRCS will provide financial assistance to support eligible producers as they implement conservation practices associated with these selected GHG projects.
Additionally, the Farm Service Agency (FSA) will implement a project to provide information to landowners who enroll in certain tree planting conservation practices under the Conservation Reserve Program and who voluntarily request an estimate of the amount of carbon stored as a result of these practices. FSA will develop a communications tool to link companies, organizations and participants in carbon storage activities and information sharing. The project will begin in 2011.
Vilsack also announced the release of USDA's Climate Change Science Plan. Details of the plan can be found at:
The plan's objective is to
incorporate management of the challenges created by climate change into the
scientific missions of USDA. It provides a guide for the Department on
scientific priorities to better serve USDA stakeholders by providing them with
information about the impact of climate change and it outlines options to
mitigate emissions and help producers adapt to expected change.
For more details on Vilsack’s comments, see:
Alberta Province Climate Change Program
Includes Agricultural Carbon Credits
One of the mandatory greenhouse gas reduction programs in Canada operates in the province of Alberta. The provincial government has imposed greenhouse gas emissions regulations on large industrial facilities. Alberta facilities that emit more than 100,000 tonnes of greenhouse gases a year are required to reduce their emissions intensity by 12 per cent under the Climate Change and Emissions Management Amendment Act.
Companies have three ways to meet their reductions. They can make operating improvements, contribute to the Climate Change and Emissions Management Fund through a carbon tax of $15 per tonne, or buy Alberta-based credits.
The Climate Change and Emissions Management Fund is a not-for-profit independent organization. The objectives of this fund are to achieve actual and sustainable reductions in greenhouse gas emissions and to assist in adapting to climate change. The money will be put into the Climate Change and Emissions Management Fund, which will be directed to strategic projects or transformative technology aimed at reducing greenhouse gas emissions in the province. The Alberta government will determine a process for how the fund is allocated to projects that qualify. It will not be a holding account for companies to deposit money they could later withdraw. (The provinces of British Columbia and Quebec also have a carbon tax program in place.)
A facility can also buy credits from large emitters that have reduced their emissions intensity beyond their 12 per cent target. They can buy credits from facilities whose emissions are below the 100,000-tonne threshold but are voluntarily reducing their emissions. This includes projects in the agriculture, forestry, and transportation sector. The projects must have legitimate greenhouse gas reductions in the province. Alberta has released draft protocols that outline how to quantify and verify emission reductions for different types of projects. For example, the protocol will specify how reducing cultivation of farm land can help store more carbon in the soil.
So there are three methods of greenhouse gas reduction available:
* Facility upgrades with the installation of new technology;
* Pay $15/tonne CO2e into a technology fund – to invest in R&D and building technology for the future;
* Purchase Alberta-made carbon offset credits.
Agriculture and forestry
are the only two industries that can remove carbon from the atmosphere.
Therefore the agricultural industry has an opportunity in the emerging offset
compliance market, both for environmental and economic benefits.
This regulation ultimately creates a market of carbon trading between emitters and farmers who sequester carbon.
Ten of the current 23
protocol standards are agriculturally related (click each project to view the
here to view the government-approved quantification protocols as well as the
project and verification guidance documents. Click to access an overview of the
Alberta Offset System.
Details on the program for Tillage System Management can be found at:
These protocols will provide quality assurance for the market and standardization of the commodity. Early action credit (ie. no-till management) of carbon sequestration are recognized back to 2002. Removals and reductions can only be counted once for compliance purposes (you can’t sell the same tonne more than once). To ensure the value of the credit, verification of projects/credits are done both on farm and at verifier’s office following government approved protocols. Several companies in Alberta are in the business of aggregating credits for sale to the industrial emitters.
For more information on Alberta’s Carbon Market and Climate Change see:
-- Steve Watson, CASMGS Communications
Adapting Agriculture to Climate Change:
New Global Search to Save Endangered Crop Wild Relatives
The Global Crop Diversity Trust has announced a major global search to systematically find, gather, catalogue, use, and save the wild relatives of wheat, rice, beans, potato, barley, lentils, chickpea, and other essential food crops, in order to help protect global food supplies against the imminent threat of climate change, and strengthen future food security, according to an article in the Dec. 27, 2010 issue of ScienceDaily.
The initiative, led by the Global Crop Diversity Trust, working in partnership with national agricultural research institutes, Royal Botanic Gardens, Kew, and the Consultative Group on International Agricultural Research (CGIAR), is the largest one ever undertaken with the tough wild relatives of today's main food crops. These wild plants contain essential traits that could be bred into crops to make them more hardy and versatile in the face of dramatically different climates expected in the coming years. Norway is providing $50 million towards this important contribution to food security.
Read the entire article at:
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