Adler, Paul (USDA-ARS, Building 3702, Curtin Road, University Park, PA, 16802-3702; Phone: 814-865-8894; Fax: 814-863-0935; Email: paul.adler@ars.usda.gov)
Climate Change Effects on Greenhouse Gas Emissions From
Bioenergy Cropping Systems in
P.R. Adler*, S.J. Del Grosso,
W.J. Parton
Reducing the net global warming potential (GWP) of energy use is a major factor driving interest in biofuels. Bioenergy cropping systems vary in contribution to the GWP due to the crop yield and resulting quantity of fossil fuels displaced, quantity and quality of C added to the soil, feedstock conversion efficiency, N2O emissions, N use efficiency, and inputs required for crop production and operation of farm machinery. The objective of the study was to use DAYCENT to model the impact of climate change on net greenhouse gas (GHG) emissions of bioenergy cropping systems (corn, soybeans, alfalfa, switchgrass, reed canarygrass, and hybrid poplar) in Pennsylvania for inclusion in a full C cycle analysis. Weather data driving climate change scenarios were from VEMAP for the no change in climate scenario and from the Canadian Centre for Climate Modeling and Analysis (CGCM1model) and Hadley Centre for Climate Prediction and Research, UK (HADCM2 model) for the climate change simulations where CO2 was assumed to double from 2004 - 2100. Without additional N, there was little response of nonleguminous crops to climate change. Alfalfa yields nearly doubled without additional N, whereas the yields of soybean were mixed depending on climate model. When the rate of N application increased 4% per year in the climate change simulations, corn, reed canarygrass, and switchgrass yields increased. Although N loss through N2O emissions and NO3-N leaching also increased with N application, further optimization will minimize these loses. Reed canarygrass had the highest N2O emissions and NO3-N leaching followed by corn and switchgrass and then soybeans and alfalfa. The greatest increase in soil C levels occurred with switchgrass, followed by corn, soybean and reed canarygrass were about neutral, and during the alfalfa segment in the corn soybean alfalfa crop rotation, soil C decreased. The quantity of displaced fossil fuel was the largest GHG sink. Soil C sequestration was the second largest GHG sink. Although crops with higher soil C inputs, such as switchgrass and hybrid poplar, will have higher equilibrium soil C levels, the change in system C will approach zero in the long term. N2O emissions were the largest GHG source. When the credit for the amount of fossil fuel displaced was not taken into account and soil C storage was assumed to have reached its maximum capacity, switchgrass and hybrid poplar were the only cropping systems to remain a sink for GHGs. Therefore, use of switchgrass and hybrid poplar for production of biofuels has the potential to be GHG neutral and may even be a long-term sink for GHGs.
Al-Kaisi, Mahdi (Iowa State University, Department of Agronomy, 2104 Agronomy Hall, Ames, IA, 50011; Phone: 515-294-8304; Fax: 515-294-9985; Email: malkaisi@iastate.edu)
Agricultural Production Practices - Effect on Soil Carbon Dynamics and Carbon Dioxide Emission
M.M. Al-Kaisi*, M.A.Licht, X. Yin
Soil carbon change and carbon
dioxide emission due to different tillage systems need to be evaluated to
encourage the adoption of conservation practices to sustain soil productivity and
protect the environment. We hypothesize that soil carbon storage and carbon
dioxide emission respond to conservation tillage differently from conventional
tillage because of their differential effects on soil properties. This study
was conducted from 1998 through 2001 to evaluate tillage effects on soil carbon
storage and carbon dioxide emission in Clarion-Nicollet-Webster soil
association in a corn [Zea mays
L.]-soybean [Glycine max (L.) Merr.]
rotation in Iowa. Treatments included no-tillage with and without residue,
strip-tillage, deep rip, chisel plow, and moldboard plow. No-tillage with
residue and strip-tillage significantly increased total soil organic carbon and
mineral fraction carbon at the 0- to 5- and 5- to 10-cm soil depths compared
with chisel plow after 3 years of tillage practices. Soil carbon dioxide
emission was lower for less intensive tillage treatments compared with
moldboard plow, with the greatest differences occurring immediately after
tillage operations. Cumulative soil carbon dioxide emission was 19 % to 41%
lower for less intensive tillage treatments than moldboard plow, and it was 24%
less for no-tillage with residue than without residue during the 480-hour
measurement period. Estimated soil mineralizable carbon pool was reduced by 22% to 66% with less
intensive tillage treatments compared to moldboard plow. Adopting less
intensive tillage systems such as no-tillage, strip-tillage, deep rip, and
chisel plow and better crop residue cover are effective in reducing carbon
dioxide emission and thus improving soil carbon sequestration in a corn-soybean
rotation.
Albaladejo, Juan (CEBAS-CSIC,
Campus de Espinardo, Murcia, MU, 30100, Spain; Phone: ++34 968 396338; Fax:
++34 968 396213; Email: jalba@cebas.csic.es)
Carbon Fraction and C-CO2
Released in Abandoned Agricultural Soils
C. Garcia, J. Albaladejo*,
J.A. Pascual, J.L. Moreno, F. Bastida, T. Hernandez
Soil is an important natural resource that needs to be preserved. However, the need to maintain increasing levels of production have led to inappropriate soil management and the consequent loss of soil fertility. When a soil is exposed to degradative processes (for example, abandonment after intensive agricultural practices, devegetation), its biological state is the first to be affected, diminishing its productive capacity. This fact is of paramount importance since, as it is widely accepted, metabolic activity is essential to the suitable functioning of ecosystems. The microbial metabolic activity of soil is responsible for the mineralization and humification of any organic components, including recalcitrant ones, reaching the soil. One important characteristic of the soils of the Mediterranean regions is that they are indeed submitted to erosion and desertification processes and that they have a low organic matter content. Intensive cultivation, continual ploughing and forest fires, allied to years of unsuitable agricultural practices, have had an important effect on humification processes and on properties associated with degradation. All the above has led to a great diminution in the quantity of vegetal remains provided to the soil, while the humus is undergoing a process of accelerated mineralization as a result of tilling. The inevitable result is a progressive diminution of the organic matter content and the negative consequences entailed. Changes in soil organic matter and several carbon fraction in abandoned semiarid agricultural soils, at different times after abandonment in comparison with natural soils exposed to the same climate have been studied. Total organic C and water soluble C showed a decrease in the abandoned soils. The scarce quantity of plant residues in these soils can be responsible for this effect. Microbial Biomass C (MBC) can be considered to be a more sensitive indicator of soil quality than organic matter or total organic C, since it responds more rapidly and to a greater extent to changes (e.g. degradation). The value of MBC detected in the abandoned soils varied greatly. It declined when agricultural soils were abandoned and decreased with time elapsed, presumably as a consequence of the loss of the capacity to protect soils against erosion processes. Soil respiration (CO2 loss) is a good indicator of soil microbial activity. CO2 losses in all the abandoned soils were significantly lower than in natural soils, particularly in the soils abandoned for the longest period of time, the importance of the duration of abandonment on microbial activity being again demonstrated.
Albaladejo, Juan (CEBAS-CSIC,
Campus
Restoration of Desertified Lands by Organic Amendment: Medium-Term Effect on Carbon Sequestration
J. Albaladejo*, M.
Martinez-Mena, R. Ortiz, J. Lopez, V.Castillo
Soil erosion and degradation in desertification-prone areas lead to a drastic decrease in the soil potential for carbon sequestration. Restoration of degraded lands could be a way to reverse this environmental degradation process in semiarid areas and mitigation of greenhouse gases. The strategy of restoration used in this experiment starts from the hypothesis that the improvement of soil characteristics favours the growth of a spontaneous vegetal cover, stimulating de carbon cycle. The aim was to evaluate the effectiveness at medium-long term of a unique addition of organic refuse on the soil potential for carbon sequestration. An addition of 25 kg m-2 of solid urban refuse was applied, in 1988, into the top 10 cm of a 85 m-2 plot, with other plot without treatment as control. The plots are sited in an open scrubland, (2-4% cover) of desertic appearance, with 5% slope. The climate is semiarid to arid with 300mm of average total annual precipitation and 17º C annual mean temperature. The soil is a Xeric Torriorthent with high physical and biological degradation. Sixteen years later a monitoring was carried out to state the lasting of the organic addition effect on the SOC pools and soil physical characteristics improvement. The TOC contents were 9.5 g kg-1 and 16.4 g kg-1 in the control and restored plots respectively. This mean 1.42 kg m-2and 2.46 kg m-1 of OC in the control and restored plot, respectively, in the top 10cm of the soil. Thus, the land restoration led to 10.3 Mg ha-1 of C sequestration. An important pool of the sequestered C remains in the soil as recalcitrant pool. This assumption may be supported by two facts: 1) The texture is coarser in the restored plot than in the control, probably due to the increase in microaggregates clay-humus, strongly stabilized and very difficult to breakdown for chemical dispersion, and 2) The higher difference between TOC and humic substances C in the restored plot, showing that an important proportion of SOC after restoration, was incorporated into the soil as long-term stable humin. Likewise, statistically significant higher values in bulk density, saturated hydraulic conductivity and aggregate stability were displayed in the restored plot at 0-10 cm depth. Soil porosity and water retention capacity showed, as well, higher mean values in the restored plot, but without significant differences. In addition, soil erosion was strongly reduced. The ratio annual sediment in restored plot/annual sediment in control plot, range from 18.8.10-3 to 1.7.10-3 along the years. The results obtained in this experiment point out the effectiveness of restoration of eroded and degraded soils, by means of an unique addition of organic amendment, to increase the recalcitrant pool of SOC.
Allen, L. H. (USDA-ARS & Agronomy Department, University of Florida, P.O. Box –110965, Gainesville, Florida, 32611-0965; Phone: 352-392-8194; Fax: 352-392-6139; Email: LHAJR@mail.ifas.ufl.edu)
Soil Organic Carbon and Nitrogen Accumulation of Rhizoma Perennial Peanut and Bahiagrass Grown under Elevated CO2 and Temperature
L.H. Allen*, S.L. Albrecht, K.J. Boote,
J.M.G. Thomas, K.
Carbon sequestration in soils might mitigate the increase of
CO2 in the atmosphere. Rhizoma perennial peanut (RPP) and bahiagrass (BG) were grown at Gainesville, FL in field soil
plots at four temperature zones (baseline-ambient, +1.5, +3.0, and +4.5
Celsius) in temperature-gradient greenhouses at 360 and 700 ppm
CO2 from 1995 to 2000. In addition to measurements of growth and
herbage yield, soil samples from the top 20 cm of each plot were collected in
February 1995 before establishment, and before new growth began each year
thereafter, including December 2000 when the study ended. February 1995 and
December 2000 samples were analyzed for soil organic carbon (SOC) and nitrogen
(SON) for each species, CO2 concentration, and temperature. First,
across all treatments of the six-year period, SOC increased 26% and SON
increased 34%. Mean SOC increase was 1.396 and 0.746 g/kg in BG and RPP,
respectively, indicating that BG sequestered more SOC than RPP. Mean SOC gain
of BG at 700 and 360 ppm CO2 was 1.450 and
1.343 g/kg, respectively, indicating that elevated CO2 caused only a
slight increase in SOC. However, mean increase of RPP at 700 and 360 ppm CO2 was 0.949 g/kg and 0.544 g/kg,
respectively, indicating that elevated CO2 caused a significant
increase in SOC in RPP plots. No response of SOC to temperature was found in
BG, but SOC decreased with temperature in RPP plots. Growth of both forages
caused an increase in SOC, but responses to CO2 and temperature were
species dependent. Generally, SON responses were similar to SOC, but SON was
much less affected by CO2 concentration. From these data we
calculated a SOC accumulation of 540
kg/ha per year from the 6 years of data. Removing the CO2 effect
gave 425 kg/ha per year of SOC.
In 1998, from a side by side comparison of soils under continuous tillage
(winter small grain crops or fallow) and under 15-years of continuous unharvested RPP at Gainesville, FL, Allen and Nelson
(unpublished), found 370 kg/ha per year
accumulation of SOC for RPP. This is consistent with RPP accumulating less SOC
than BG. Comparing data, W.A. Albrecht (1938) reported an accumulation of 380 kg/ha per year across a 14-year
red clover study in
Amado, Telmo (Univ.of Santa Maria, Soil Departament, Federal University of
Santa Maria, Santa Maria, RS, 97105-900, Brazil, Phone: (55)2208916; Fax:
(55)2208256; Email: tamado@smail.ufsm.br)
Carbon Sequestration in No-Tillage Systems with Intensive
Use of Cover Crops in
T.J.C. Amado*
Amichev, Beyhan (Virginia
Tech ,
B.Y. Amichev*, J.A. Burger
Carbon accreditation of forest development projects is an essential approach to sequestering atmospheric C under the provisions of the Kyoto Protocol. Standard soil C accounting methods tend to largely overestimate the C contained in soil-incorporated organic matter on mined lands. This study was conducted (i) to determine the distribution pattern and variation of soil C stock down the soil profile and across space and (ii) to compare two methods of precision soil C accounting on mined land. We measured the soil C content on 9 mined sites reclaimed to pastureland in the period after the passage of Surface Mining Control and Reclamation Act of 1977 (SMCRA). Mine soil samples of the surface soil layer (topsoil) and the subsurface overburden material (mine spoil) were collected; chemical and physical soil properties were determined on the less-than-2mm fine sample fraction. Soil C stock maps were generated using common geostatistical procedures in ArcGIS 8.2® software. Our results show that the soil C variation across space was greater in the mine spoil (CV of 35% to 81%) compared to the topsoil (CV of 31% to 53%). Bulk density of the fine fraction (BD), C:N ratio (CN), coarse fragment content (CFC) and electrical conductivity (EC) explained between 54% and 91% of the variation of mine spoil C stock. Percent sandstone (SS), CN, and BD explained between 33% and 92% of the variation of topsoil C stock. The mean soil C stock computed as the average of collected soil samples was greater than that derived from the soil C stock maps. On average the C content decreased 30% for every 10 cm down the mine soil profile. There was no evident pattern in the vertical distribution of soil C most likely due to irregular alterations of soil properties down the soil profile during the many years of mine spoil weathering.
Amonette, James E (Pacific Northwest National Laboratory,
Enhancing Soil Humification: Insights from a Model System
J.E. Amonette*, J.B. Kim, C.T. Garten, C.C. Trettin, R.S. Arvidson, A. Luttge
Our research has focused on understanding the fundamental process by which humus is created (i.e., humification) and extending this knowledge to enhance the rate of humification. The rate-limiting step in the humification process appears to be the oxidation of polyphenols to quinones. These quinones then react with peptides and amino acids to form large melanin-like polymers that resist further degradation by microorganisms.
Soil fungi produce enzymes such as polyphenol oxidases and laccases that catalyze the oxidation step. Soil minerals, such as iron and manganese oxides, can also perform this function. We have observed a significant synergetic effect when a polyphenol oxidase (tyrosinase) and a mineral phase (e.g., mesoporous silica, manganese oxide, alkaline fly ash) are both present. As soil enzyme activity depends on structural conformation, and longevity depends on protection from microbial predation, we are examining the nature of enzyme attachment to soil particles and the impact of physical properties such as pore size on activity and longevity.
This presentation summarizes our laboratory results obtained using a model tyrosinase-enzyme-based reaction system. We perturbed the system by adding various co-catalysts and by changing the availability of oxygen and moisture. Our results yield insights into reaction mechanisms and suggest possible management strategies for enhancing soil-C sequestration.
We conclude that co-catalysis of humification occurs by three mechanisms involving physical stabilization of tyrosinase, direct oxidation of the monomers, and promotion of the oxidation and condensation steps by alkaline pH. Although tyrosinase activity is greatest at neutral pHs, the large pH dependence of the condensation step drives the overall reaction to maximum rates under alkaline conditions. Liming of soils to slightly alkaline pH should enhance net carbon sequestration.
Alkaline fly ash is a potential liming agent for soils, provided that the carbon costs associated with transportation from the source are less than the organic carbon that is humified. Soils that contain carbonate require flyash with relatively high-unburned C content (charcoal residual) to sustain a net positive sequestration. The porous charcoal residue provides sorption sites for the enzyme and for the organic monomers involved, which otherwise would attack and dissolve soil carbonates.
Amos, Brigid (University of Nebraska-Lincoln, 236 Kiem Hall, Dept. of Agronomy and Horticulture, Lincoln, NE, 68583-0915; Phone: 402-472-7989; Email: bamos2@unlnotes.unl.edu)
Approaches to Separating Autotrophic and Heterotrophic Contributions to Soil Respiration in Maize-Based Agroecosystems
B. Amos*, D.T. Walters, S. Madhavan, T.J. Arkebauer, D.L. Scoby
We will present two approaches to separating soil respiration into two specific sources: an autotrophic source (Ra), defined as combined root respiration and the respiration of soil microorganisms residing in the rhizosphere and deriving energy from root exudation and turnover, and a heterotrophic source (Rh), defined as the respiration of soil microorganisms and macroorganisms not directly under the influence of the live root system and deriving energy from soil organic matter. The two approaches discussed are the root exclusion technique (i.e., measuring soil respiration with and without roots) and a method in which delta 13C measurements are made of soil respiration samples collected from root-excluded and non root-excluded soil. These methods were used to separate Ra and Rh in irrigated and rainfed maize-based agroecosystems in the western USA Corn Belt. We will present preliminary results and consider the advantages and potential pitfalls of both methods.
Antinori, Camille (Lawrence Berkeley National Laboratory, Environmental Energy
Technologies Div., LBNL, One Cyclotron Road, 90-R4000, Berkeley, CA,
94720; Phone: 510-495-2277; Fax: 510-486-6996; Email: cmantinori@lbl.gov)
Transaction Costs of Project-Based Carbon Reduction: Evidence from the Forestry Sector
Camille
Antinori, Jayant Sathaye, Ken Andrasko*
Recognition of the need to address global climate change has created a new market for trading carbon emissions reductions. This paper considers whether transaction costs may hinder this market’s further growth and development. Transaction costs refer to costs beyond production required to make a trade, such as search for trading partners, contract writing and negotiation, monitoring, regulatory approval, as well as the overall risks of undertaking the project. We focus on ten projects in the forestry sector in Asia, Latin America and the US. We develop and use a common framework for categorizing transaction costs, and using project-specific data estimate costs for a nascent (i.e., current early, thin market) and a mature emissions reduction market, and with and without insurance costs. We conclude that transaction costs decline as the log of the project size, and that costs are lower in a mature compared to the current nascent market.
Arkebauer, Tim (University of Nebraska-Lincoln, 106 KCR Bldg., Department of Agronomy and Horticulture, Lincoln, NE, 685830817; Phone: 402-472-2847; 402-472-3654; Email: tja@unl.edu)
Soil Surface CO2, N2O and CH4 Fluxes and Annual Estimates of Ecosystem Respiration and Global Warming Potentials in Maize-based Agroecosystems
T.
Arkebauer*, H. Shen, D. Scoby
Recent changes in global climate have been characterized by increasing atmospheric concentrations of CO2, CH4 and N2O. Mitigation strategies include sequestering atmospheric carbon in soils. The maize-based cropping systems that dominate the Great Plains may have significant carbon sequestration potential. The primary goal of our program is to quantify ecosystem respiration and global warming potential through near-continuous year-round measurement of soil surface CO2, N2O and CH4 fluxes in the maize-based cropping systems of the Great Plains region. We are integrating the three gas fluxes over diel, seasonal and annual time scales for comparison among various treatments (e.g., maize vs. soybean, irrigated vs. rainfed). We are analyzing flux readings in terms of supporting measurements (e.g., soil temperature, soil moisture content, leaf area index, biomass) in order to elucidate the effects of relevant controlling factors. We are also focusing on scaling up single leaf respiration rates to the canopy level by drawing on seasonal LAI and leaf N content measurements in conjunction with continuously recorded canopy air temperatures. Using these data, we estimate annual ecosystem respiration and global warming potentials for each cropping system and compare results between the various systems.
Atwood, Jay (USDA-NRCS-RIAD,
808 East Blackland Road, Temple, TX, 76502; Phone: 254-770-6632; Fax:
254-770-6561; Email: jatwood@brc.tamus.edu)
Effect of the Conservation Reserve Program (CRP) on Soil Carbon
J.D. Atwood*, S.R. Potter, J.R. Williams, M.L. Norfleet
The CRP effect on the rate of cropland soil carbon (C)
storage was estimated. The analysis
included the 89.6 percent of the 32.7 million acres classified as CRP in the 1997
National Resource Inventory (NRI) for which successful model simulations could
be completed. Two scenarios were
simulated: 1) a CRP scenario reflecting management according to the 1997 NRI
and contracted CRP practices for the first 12 signup periods; and 2) a Crop
scenario that assumed the crop mix reported in the NRI preceding CRP enrollment
would have continued, but with tillage, conservation practice, and nutrient
management at 1997 levels observed on non-CRP land. Individual NRI CRP sample
points were grouped into 2,570 clusters according to climate, soil, and
landscape characteristics. For each
cluster, multiple crop simulations were defined for the diverse mix of prior
crops and tillage systems of the NRI points in the cluster and up to four CRP
simulations were defined for native grass, introduced grass, tree, and wildlife
habitat cover types. A total of 20,514
simulations were required for the Crop and CRP scenarios. The simulations were
30 years in length and were replicated for five sets of randomly generated
daily weather to remove year-to-year variation in model output due to weather
patterns rather than due to program effects.
The annual model output was divided into three periods for analysis: 1)
years 1 to 10 reflecting the duration of most CRP contracts; 2) years 11 to 20
reflecting benefits of CRP re-enrollment as contracts expire; and 3) years 21
to 30 reflecting benefits for longer term CRP easements. The CRP C benefit (C
sequestration rate) was calculated as the rate of CRP soil C storage minus the
rate of continued cropping soil C storage.
On average, the CRP C benefit was 0.90, 0.49, and 0.36 tons per acre per
year in years 1 to 10, years 11 to 20, and years 21 to 30, respectively, for
total annual C storage increases of 26.2, 14.3, and 10.6 million tons in the
three periods for the 29.3 million acres simulated. In years 1 to 10, the CRP C benefit ranged
from a low of 0.7 tons per acre per year in the Northeast to a high of 1.1 tons
per acre per year in the Upper Midwest.
Within the regions, the standard deviation of the CRP C benefit, where
the sample was the set of averages calculated by soil and climate class, varied
from 0.56 tons per acre per year in the Southern Great Plains to 1.17 tons per
acre per year in the Upper Midwest. With
continued cropping, 45 percent of the land would lose five percent or more C in
years 1 to 10; with conversion to CRP only three percent would lose more than
five percent C. With continued cropping
in years 21 to 30, the area losing more than five percent of soil C increased
to more than 48 percent. With continued cropping approximately 20 percent of
the area gained more than five percent carbon in years 1 to 10; whereas with
CRP, approximately 85 percent of the land gained more than 5 percent carbon in
the first 10 years. The percent of the
CRP land gaining more than five percent carbon was about equal at the national
level in the second and third periods, near 20 percent, implying a gradual
convergence towards new, stable, higher soil C levels sometime after the second
or third period. The estimated CRP C storage benefit varied according to
tillage method used for the continued cropping.
In years 1 to 10, the CRP C storage benefit relative to conventional,
mulch, and notill cropping systems for non-forage crops was estimated to be
1.16, 1.02, and 0.50 tons per acre per year, respectively. In years 21 to 30 the CRP C storage benefit
was nearly equal across all tillage types.
Bair, Lucas (USDA-FS, Corvallis, OR Forest Science Laboratory, 3200 SW Jefferson Way, Corvallis, OR, 97331; Phone: 541-750-7422; mail: lbair@fs.fed.us)
Projecting Private Forest Investment and Forest Carbon with the Forest and Agricultural Sector Optimization Model – Green House Gas
L.S. Bair*, R.J. Alig
Study of landowner behavior aids in designing more effective incentives for promoting activities to mitigate climate change, and owners of private timberland could play important roles in any forestry-related contributions to reducing net greenhouse gas emissions. The Forest and Agricultural Sector Optimization Model—Green House Gas version (FASOMGHG) is a dynamic, nonlinear programming model of the forest and agricultural sectors in the United States that we used to model private timberland investment behavior over a one hundred year projection. FASOMGHG is the successor to the Forest and Agricultural Sector Optimization Model (FASOM) and endogenizes timber investment, harvest, and price to simulate allocation of land over time to competing activities in both the forest and agricultural sectors and the resultant net greenhouse gas emissions. We updated the forest sector data in the FASOMGHG model to provide more specific forest type and management intensity class information. For example, the model now differentiates seven planted pine management intensity classes for the U.S. South, compared to two classes in the 1990s FASOM model. The results of the baseline scenario in FASOMGHG illustrate the potential impact of intensive management on national timber production and net greenhouse gas reductions when implemented by private timberland owners. Preliminary findings indicate that allocation of timberland area to high intensity management leaves a large area under private management to relatively low management intensities. Alternative scenarios will be implemented to identify the allocation of management intensities by private timberland owners when, for example, investment in high levels of management is restricted.
Baisden, W. Troy (Landcare
Research, New Zealand Ltd, Private Bag 11052, Massey Univ Campus,
Palmerston, North5300, New Zealand,
Phone: +64 6-356 7145; Fax: +64 6-355-9230; Email:
baisdent@landcareresearch.co.nz)
Making Carbon-Trading Mechanisms Accessible to Indigenous
Groups: Lessons From Working with Maori in
G. Harmsworth, W.T. Baisden*
Many researchers and policy makers acknowledge that land owned and managed by indigenous groups differs from land owned and managed under more Western ownership and governance-type models. Differences may include characteristics such as landownership and management structures, historical connection, and land quality, as well as legislation, and policies and practice that guide land use and management. Designing policy instruments to permit C trading within a nation therefore needs to recognise these differences where indigenous populations exist and to design policies that are cognisant of differing land-governance frameworks, economic status, and socio-cultural aspirations. We describe research we are conducting with a range of stakeholders – mostly landowners and policy agencies – to identify opportunities for indigenous Maori to contribute through forest carbon sinks to help New Zealand meet its commitments under the newly signed Kyoto protocol. We have focused our work to date on the North Island East Coast Region of New Zealand, an area with extensive undeveloped and erosion-prone Maori land. In this research we have defined the areas of Maori owned land under different forms of land use, vegetative cover, and land capability or type. We are in the process of determining the economic and policy considerations required to increase Maori participation in New Zealand’s afforestation-based climate change mitigation policy. Perhaps surprisingly, our 2 key findings describe: 1) the need to understand complex governance structures for Maori land, often involving tens to hundreds of owners – many of whom are absent from participatory decision-making, and 2) the need to determine Maori community aspirations for land. We find that appropriate land-covenanting policies can be modeled on existing policies to maintain and enhance biodiversity, but that all policies must consider governance. There is a need to develop appropriate models and contracts for income generation for distinct land areas through time, often dealing with successive ownership generations (at least 50 years), and identifying successive sources of income. Additionally, we have identified that the most important contribution on Maori land for climate change mitigation may be to develop initiatives that reduce indigenous scrub clearance, such as for plantation forestry and pasture, rather than just encourage the regeneration of native forests as we had originally assumed. These findings emphasize the importance of developing an integrated socio-economic understanding of Maori land that identifies community, district, and regional aspirations to achieve long-term success, realise potential opportunities, and effect change. We present our research as a model for effectively working with indigenous groups in the development of carbon trading, either within developed nations or in CDM projects.
Baisden, W. Troy (Landcare Research, New Zealand Ltd, Private Bag 11052, Massey Univ Campus, Palmerston, North5300, New Zealand; Phone: +64 6-356 7145; Fax: +64 6-355-9230; Email: baisdent@landcareresearch.co.nz)
High Riverine Transport of Particulate Organic Carbon in New Zealand: Potential Significance of Soil Erosion to Carbon Accounting
D.T. Scott, W.T. Baisden*, N.J. Preston, N.A. Trustrum, R. Davies-Colley, R.A. Woods, D.M. Hicks, B. Gomez, M.J. Page, K.R. Tate
Tectonically active small island nations contribute a disproportionate amount of sediment to the world’s oceans-. For such nations, particulate organic carbon (POC) export associated with riverine sediment load can also be important compared with C fluxes reported under the United Nations Framework Convention on Climate Change (UNFCCC) and accounted for under the Kyoto Protocol. We quantified the total riverine export of particulate organic carbon (POC) from New Zealand’s landscape to the ocean. New Zealand comprises 0.1% of global land area, 0.2% of the world’s CO2 emissions, and 1% of global riverine sediment flux. POC export was estimated at 3±1 Mt C yr-1 (10±3 tC km-2yr-1). The total POC yield represents a movement of C equivalent to approximately one third of New Zealand’s total fossil fuel emissions, although this erosional flux cannot be treated as an emission to the atmosphere since a large proportion of POC may be sequestered in ocean sediments. Since elevated rates of erosion are associated with non-forested landcover, reforestation may contribute to changes in riverine POC fluxes. However, our calculations suggest that only 1.7% of New Zealand’s land area yields sufficient human-induced POC to rivers to be of concern in C accounting. Our approach of identifying ‘hot spots’ of erosion where significant uncertainties may interfere with C accounting potentially allows C accounting and trading to proceed based on existing rules in the vast majority of the landscape.
Baisden, W. Troy (Landcare Research, New Zealand Ltd, Private Bag 11052, Massey Univ Campus, Palmerston North, 5300, New Zealand; Phone: +64 6-356 7145; Fax: +64 6-355-9230; Email: baisdent@landcareresearch.co.nz)
Significant Bomb C-14 Responses in Soils Below 30 cm Depth: A Previously Unrecognized Decadal C Pool?
W.T. Baisden*
Globally, soil organic matter contains approximately 1500 Pg C to 1 m soil depth and 2300 Pg C to 3 m depth—more than biomass and atmospheric CO2 combined. Efforts to account for the effects of land-use or vegetation change on soil organic carbon (SOC) stocks normally limit their focus to the upper 20–30 cm of the soil profile, yet 0–20 cm SOC stocks are only 42% of 0-1 m SOC. Accounting for only the upper 20–30 cm of SOC has been justifiable based on the assumption that deeper SOC is unreactive since it displays 14C-derived mean residence times of hundreds or thousands of years. Recent findings indicate that, at depths of 40–100 cm, a well-studied New Zealand silt-loam soil displays progressive Delta 14C enrichment of over 200 per mil across samplings in 1959, 1974 and 2002, indicating incorporation of bomb 14C during the last 40 years. This pattern of deep 14C enrichment – previously observed in two well-drained California grassland soils – suggests that roots and/or dissolved organic C (DOC) transport contribute to a Decadally-Reactive Deep Soil C (DRDSC) pool. Soil sampled in 1970 and 2002 from a chronosequence of New Zealand sand dunes deposited from ~100 to 15,000 years ago confirms this pattern of deep soil response to the bomb14C spike. However, in these better drained profiles in more humid climates, the bomb- 14C pulse has passed at depths of 55–80 cm, evidenced by a Delta 14C decline of ~70 per mil. This SOC pool can react to land-use or vegetation change.
Bangsund, Dean (North Dakota State University, P.O. Box 5636, Fargo, ND, 58105; Phone: 701-231-7471; Fax: 701-231-7400; Email: bangsund@ndsuext.nodak.edu)
Carbon Sequestration in Spring Wheat Producing Regions of
the
D.A.
Bangsund*, F.L. Leistritz
Carbon sequestration in crop land is currently viewed as a low-cost option to mitigate the increase in greenhouse gas emissions. Existing research suggests that at low carbon prices the primary carbon sequestration activities would be changes in tillage practices and as carbon prices increase some changes in land use are likely to occur in various regions of the United States. This study evaluated land management and land use alternatives that are likely to occur with carbon incentives in the northern Great Plains. Historically, the region has relied heavily on the use of summer fallow; however, producers are finding economic advantages in adopting conservation and no-till systems in continuous cropping practices in the absence of external incentives. Further, producers in the region have consistently demonstrated a willingness to enroll crop land in long-term conservation programs. The conversion of crop land to perennial grasses is an alternative land use that has high carbon sequestration potential in the northern Great Plains. Producers within the region were differentiated by three levels of profitability and by three types of tillage practices. The highest expected net present value of a future stream of carbon payments and net returns associated with tillage and land use alternatives was determined for each combination of profitability and tillage practice. Results suggest that by including modest revenues from co-products, perennial grass is not only an economically viable alternative to crop production in the region, but may be economically viable at carbon prices lower than have been previously suggested. In addition, just as soil type, crop rotations, and tillage practices have been used to differentiate carbon sequestration potential within a given area, this study indicates that profitability measures also should be used to further differentiate the response of producers to carbon incentives.
Bernacchi, Carl (Illinois State Water Survey, 2204 Griffith Drive, Champaign, IL, 61820; Phone: 217-333-8048; Fax: 217-244-0220; Email: bernacch@uiuc.edu)
Carbon Budget of Mature No-till Ecosystem in North Central
Region of the
C. J. Bernacchi*, S.G. Hollinger, T. Meyers
Continuous measurements of carbon flux data from 1997 through 2002 were used to evaluate the carbon budget for a no-till maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) rotation agricultural ecosystem using the eddy covariance technique. These measurements were used to determine the Net Ecosystem Exchange of carbon (NEE) at the local and regional scales. Results show that on the local and regional scales, the maize/soybean no-till ecosystem is a carbon sink; however, corn is the dominant sink in the ecosystem. Locally, the sink is mostly explained by the carbon stored in the grain, which is removed from the field during harvest. On a regional scale, the sink is proportionally lower than that of the local scale, which is attributed to regional consumption of the grain. Nearly 100% of both maize and soybean yields are consumed annually, e.g., all carbon stored in grain is consumed somewhere in the world. The grain consumption results in a much lower carbon sink, but the results imply that long-term carbon-sequestration potential of this no-till ecosystem exists.
Birdsey, Richard (USDA-Forest
Service, 11 Campus Blvd, Suite 200, Newtown Square, PA, 19073; Phone:
610-557-4091; Email: rbirdsey@fs.fed.us)
Carbon Accounting Rules and Guidelines for the United States Forest Sector
R. Birdsey*
The President’s Climate Change Initiative includes improvements to the Department of Energy’s Voluntary Greenhouse Gas Reporting Program. As part of the initiative, the USDA Forest Service is developing accounting rules and guidelines for reporting and registering forestry activities that reduce atmospheric CO2 by increasing carbon sequestration or reducing emissions. To be eligible for registration, the reported reductions must use methods and meet standards contained in the guidelines. Forestry presents some unique challenges and opportunities because of the diversity of operations (e.g. size and location of operations), the variety of practices that affect greenhouse gases, the year-to-year variability in emissions and sequestration associated with forest activities, and some special considerations such as accounting for the effects of natural disturbance. Forestry activities with potential for achieving substantial reductions include, but are not limited to: afforestation, mine land reclamation, and forest restoration; agroforestry; forest management; short-rotation biomass energy plantations; forest preservation; wood products; and urban forestry.
Bohm, Sven (Michigan State
University, 3700 Gull Lake Dr, Hickory Corners, MI, 49060; Phone: 51-3550223;
Email: bs@rootimage.msu.edu)
S. Bohm*, G.P. Robertson
We are using automated static chambers for frequent measurements of N2O emissions from soils under four different agricultural management systems (conventional, no-till, and organic soybean-wheat-corn rotations and continuous alfalfa). N2O emissions are sampled four times per day, and simultaneous measurements of soil moisture and temperature provide ancillary emission data, as do periodic soil nitrate measurements. Fluxes vary smoothly over the time period thus far measured, suggesting that we are capturing most of the temporal variability present in the systems. N2O emissions often vary more than three-fold over a single day. Longer term trends appear related to soil moisture, temperature, and nitrogen availability. Maximum fluxes were nearly ten times higher in the conventional treatment than in the other treatments. Data will be used to test current models of N2O emission, including DAYCENT.
Bolstad,
P. V. (University of Minnesota Dept. of Forest Resources, 115 Green Hall, St.
Paul, MN, 55108; Phone: 612 624-9711; Fax: 612 625-5212; Email:
pbolstad@umn.edu)
Simulating Carbon Dynamics
in Forests - What May We Learn From Agriculturalists?
P.V. Bolstad*
More studies have focused
on agricultural management and soil carbon (C) than on forests, forest
management, and soil C storage. This is in part due to the relatively broader
and deeper understanding of management impacts on agricultural soils, the range
of management options possible in agroecosystems, and the history, number, and
breadth of long-term soil C studies in agricultural settings.
There are a large and growing number of soil carbon models, and these models
differ in their objectives, structure, and outputs. Many models focus on
intensively managed, annual agricultural systems; a smaller set have focused on
extensively managed or unmanaged systems, predominantly forests or grasslands,
and a smaller set have been developed and tested across both forest and
agricultural ecosystems at a range of management regimes. This talk describes
and contrasts the basic approaches used in soil C models for agricultural and
forested systems, evaluates the ability to integrate
changes in forest management regimes on predictions in forest soil and
ecosystem C storage, and identifies steps necessary to integrate management
sensitivity and improve the quality of forest soil C models.
Borgo, Marília (SPVS, Rua
Gutemberg, 296, Batel, 80420-030, Curitiba, Pa; Curitiba, PR, 80420-030,
Brazil; Phone: 0412420280; Fax: 0412420280; Email: maborgo@spvs.org.br)
M. Borgo*, G. Tiepolo, D.N. Cardoso, I.A. Andrade
The Atlantic Rainforest Restoration Project (ARRP – Cachoeira
Natural Reserve) implemented by Wildlife Research and Environmental Education
Society (SPVS) in a partnership with The Nature Conservancy and General Motors
has a current area of 8,600.0 ha and it is located at Paraná state, Brazil,
within Environmental Protection Area of Guaraqueçaba. A vegetation map for the
ARRP area was done and several types of forests and their sucessional stages
and other land uses were identified and classified. Vegetation stratified
sampling was done using forest coverage (Submontane Forest, Wetland forest,
Advanced/medium, Medium and Young Secondary Forest, according to the period
that the original forest coverage had been disturbed). Another sampling based
on soil and vegetation maps was conducted in the same plots used in the simple
stratification. In addition to those forest strata, other non-forest classes
such as pasture, herbaceous and shrubs vegetation were also included as part of
the carbon inventory, but temporary plots were used for those strata. The
methodology chosen for the carbon inventory was the one developed by Winrock
International and adapted to the project conditions. For the vegetation classes
of pasture/shrub and open areas destructive sampling was carried out in 24
plots. The total aboveground biomass for non-forest strata in ARRP was 3732 t
C. The total carbon in the forest strata (excluding soil) was 764.847 t C. The
overall weighted mean of total carbon content of forests is 88 t C ha-1, 77 %
of which in the aboveground biomass. Total dead wood carbon represents about
6.1% of the aboveground carbon biomass. Small trees (dbh greater than 5 cm)
represented 1.5% of total biomass and roots were 20% of the aboveground
biomass, and represents 15% of the total amount. Considering just aboveground
biomass, there is a total pool of 577,555 t C. Coefficients of variation for
aboveground total carbon content by strata were relatively low except by the
lowland forest. The coefficients range from 24-33% (lowland – 91%). Seventeen
forest strata were distinguished by combining soil classes and vegetation
types. Compared to the simple stratification, the total number of plots is
16.5% lower. The soil-vegetation stratification is better because it combines
specific environmental conditions of forest and soil classes and it reduces the
variation within each vegetation class. The total carbon in the forest strata
using the stratification based on vegetation and soil maps (excluding soil) was
764,812 t C. Total aboveground biomass was 589,326 and mean carbon stocks for
aboveground biomass ranged from 42-135 t C ha-1. Comparing
aboveground biomass between soil and soil-vegetation stratification, the best
sample was at the second method, with increases around 2% (or 11,700 t C) in the
total aboveground in the inventory. As a result of the carbon inventory
conducted in the ARRP it was possible to quantify the amount of carbon stored
with a good level of precision (p=0.05). The inventory was used to estimate the
differences between the with- and without-project carbon pools and is the
primary basis for determination of project GHG benefits. The results of this
effort will help to improve and develop models to measure and monitor carbon
stock in heterogeneous landscapes, such as the ones found in the Atlantic
Rainforest. This project was developed with the funds from Initiative for
Climate Action Project Research of Department of Energy (DOE) and National
Energy Technology Laboratory of USA (DE-FC26-01NT41151).
Bostick, W. McNair (University of Florida, Dept. of Ag. and Bio. Engineering, 1 Frazier Rogers, Gainesville, FL, 32611-0570; Phone: 352-392-1864 x 292; Fax: 352-392-4092; Email: mcnair2@ufl.edu)
Stochastic Simulation and Data Assimilation for Estimation of Soil Carbon Dynamics
W. M. Bostick*, J. Koo, J. W. Jones, G. Hoogenboom, V. Bado, W. D. Graham
The large land areas needed to sequester tradable amounts of carbon (C) will lead to uncertainty in estimates of soil C dynamics in sequestration projects. The objective of this paper is to present a method that uses the Extended Kalman Filter (ExKF) algorithm for assimilating simulations and measurements to reduce uncertainty in estimates. The method uses a stochastic soil C model to propagate model states, their variance and the covariance between states at different locations. When measurements are made, the ExKF updates model states at locations that are measured and unmeasured. The degree to which simulated states are updated depends the difference between simulations and measurements and on the magnitudes of the measurement variances, the simulated variances and simulated covariances of model states. In general, low measurement variance, relative to the simulation variance, can yield large state updates when measurements are assimilated. On the other hand, if simulation variance is low, relative to the measurement variance, measurements may have little effect on state estimates. Larger covariances between states at measured and unmeasured sites may yield larger updates at the unmeasured site. We demonstrate the use of this method with a long-term rotation experiment from Burkina Faso. Soil C samples from the experiment were used to initialize the initial C states. A semi-variogram model was also developed from these data and used with multi-Gaussian stochastic simulation to initialize the covariance matrix. The ExKF performance was analyzed for different measurement strategies. For all measurement scenarios considered, aggregate C estimates were more accurate than measurement or simulation results alone. In addition, the variance of the aggregate filtered estimates decreased as data were assimilated. In contrast, the variance of simulation estimates alone increased over the period of estimation.
Brenner, John (USDA-Natural Resources Conservation Service, U.S. Bancorp Tower, 111 SW 5th Avenue, Suite 1200, Portland, Oregon, 97204; Phone: 503-273-2409; Fax: 503-273-2401; Email: john.brenner@por.usda.gov)
Estimating Soil C Changes for the US 1605B Program ‘Voluntary Reporting of Greenhouse Gas Mitigation’
John Brenner*, K. Paustian, M. Easter, K. Killian, J. Schuler, S. Williams
A system for voluntary reporting of greenhouse gas emission reductions was established as part of the US policy for addressing global climate change issues. The system is administered by the USDOE and has recently been revised and improved as part of the Administration’s Climate Change Initiative. Emission reductions through agricultural activities, including soil C sequestration and reductions in on-farm fuel usage are included in the reporting system. Here we describe the design, data sources and reporting capabilities of an on-line, web-based estimation tool that is included as part of the 1605B system.
Brewer, Elizabeth (Bradley
University, 1501 W. Bradley Ave., Biology Department, Peoria, IL, 61625; Phone:
309-677-3809; Fax: 309-677-3558; Email: ebrewer@bradley.edu)
E.A. Brewer*, S.J. Morris, E.A. Paul, G.P. Robertson
A variety of land-use change strategies targeted towards increasing carbon (C) storage in terrestrial systems have focused on converting some agricultural fields to forest. Research to date suggests some strategies are more successful than others at improving belowground C stocks. Our research evaluates the potential use of calcium (Ca) and nitrogen (N) for improving soil C stabilization when agricultural lands are returned to forest. Past work suggests that sandy or acidic soils of the eastern U.S. do not sequester C under pine unless adequate Ca is present. To evaluate the degree to which Ca and/or N additions can increase C sequestration, field plots were established in an afforested red pine stand with low soil C content. Treatments included control (no amendment), addition of CaCl2, addition of NH4NO3, and additions of CaCl2 and NH4NO3. Lime was not used in this study so that contributions of lime-CO2 to atmospheric pools would not be a confounding factor in evaluating C sequestration. Each treatment was also incorporated with litter, to a depth of 20 cm. Biological fractionation incubations were established on soils collected one year after amendment, to evaluate changes in C and N pools. Incubations were also established using soil retrieved from our field site but amended in the laboratory. Amendments included all treatments used in the field but also examined Ca added as lime (CaCO3) amendments to evaluate the differential impacts of Ca source. Overall, our results suggest that impacts of Ca addition on C accrual are dependent of the form of Ca added and method of application, surface versus incorporation. Analysis for main effects and interactions suggest increases in total and resistant C pool sizes with addition of CaCl2 and litter incorporation but there were no differences in mean residence times (MRT). Field respiration measurements showed decreased respiration from CaCl2 amended plots suggesting sequestration. Impacts of N were dependent on whether N was added alone, or in the presence of Ca. Plots with N additions alone showed an increase in total C, compared to plots where N was added with Ca. Field respiration also showed the interaction with increased respiration when N was added with Ca. Nitrogen additions had little impact on N cycling parameters measured either initially or 1 year after amendment, however, CaCl2 decreased N mineralization rates further supporting sequestration. The study supports the hypothesis that Ca and N amendments will increase soil C sequestration. These treatments could easily be incorporated into management schemes and result in increases in soil C in managed systems. Longer-term measurements on these sites are necessary to extrapolate the data collected here to a viable management strategy.
Brown, Sandra (Winrock International, 621 N Kent St., Suite 1200, Arlington, VA, 22209; Phone: 703-525-9430 x 678; Email: sbrown@winrock.org)
Estimating the Potential Carbon Supply from Changes in Land Use: Afforestation of Grazing Lands in the USA as a Case Study
S.Brown*, A.Dushku, J.Kadyszewski
Most estimates of carbon sequestration potential on the land tend to be of the theoretical potential, without consideration of current land values and alternate uses. To fill this gap in knowledge, the goal of this work is to answer the basic question: “How many carbon credits would landowners offer for sale for a particular class of activity at various price points and where are these located?” Information about current land use, potential changes in land use and the incremental carbon resulting from the change, opportunity costs, conversion costs, annual maintenance costs, and measurement and monitoring costs were obtained and used in the analyses for two regions in the USA (west coast and south central states). The analyses are performed in a geographic information system (GIS) to include the diversity of land uses, rates of carbon sequestration, and costs over three time periods of 20 years, 40 years and 80 years. We will present the general approach that was used to identify and locate classes of land where there is potential to change the use to a higher carbon content, estimate rates of carbon accumulation for each major potential land-use change activity for each land class, and assign values to each contributing cost factor. Results indicate that at a price of less than $10/t C, about 230 million tons of carbon could be sequestered over 40 years by afforestation of 1.1 million hectares of existing grazing lands in Arkansas, Louisiana, and Mississippi. If the price of carbon was up to $20/ton, twice as much carbon could be sequestered on about 4 million ha in these southern states. In the western states (e.g. CA and OR), similar amounts of carbon could be sequestered by afforestation after 40 years for the same price points, but more land would be needed.
Burton, D. (Nova Scotia
Agricultural College, 20 Tower Road, Truro, NS, B2N 5E3, Canada; Phone:
902-893-6250; Fax: 902-893-0335; Email: dburton@nsac.ns.ca)
Utilization of Animal Manure in Potato Production: Reducing Greenhouse Gas Emissions Through Improved Nitrogen Management
D. Burton*, J.A. MacLeod, B. Thangaraj, B.J. Zebarth
The study, conducted at the Crops and Livestock Research Station, Charlottetown, examines greenhouse gas emissions from a potato-barley-sweet clover rotation. The objectives of the project were to: i) collect baseline information from the standard three-year potato rotation in Prince Edward Island; ii) determine the effect of different manure management strategies within the potato rotation on nitrous oxide emissions; and iii) identify the potential to reduce nitrous oxide emissions through improved nitrogen management practices. The experiment had four N fertility treatments, replicated three times. The treatments are: i) mineral fertilizer (NH4NO3) applied in the spring of the potato year of the rotation; ii) solid swine manure applied in the fall before the potato year; iii) solid swine manure applied in the spring of the potato year; and iv) liquid swine manure applied in the spring of the potato year. Spring and early summer periods (mid-May to end of June) were the times of greatest N2O emission. The potato year of the rotation resulted in the greatest N2O emissions. In the potato year solid manure resulted in less N2O emission than did liquid manure or NH4NO3. Differences in N2O emissions between years and treatments corresponded with treatment effects on soil NO3- concentration. Nitrate and N2O emissions in tile drainage water was monitored as part of parallel studies.
Camps Arbestain, Marta
(NEIKERNEIKER, Berreaga, 1DERIO-BIZKAIA, 48160, Spain; Phone: 34944034328; Fax:
34944034310; Email: mcamps@neiker.net)
Determination of Organic Carbon Fractions of Agricultural and Forest Soils on the Basis of Their Degree of Oxidation with Permanganate
M. Camps Arbestain*, Z. Madinabeitia, I. Martinez de Arano, A.Gonzalez
Arias, M. Pinto, A. Aizpurua, M.A. Ortuzar, F. Macias
The aim of the present study is to investigate the lability of soil organic carbon (SOC), measured on the basis of the ease of its oxidation with permanganate. For this, samples of the surface horizons of 44 soils under Fagus sylvatica L., 35 soils under Pinus radiata D. Don, 20 soils under Quercus ilex L., and 12 agricultural soils, all located in the Basque Country (N Spain), were analyzed. Most of the soils under Fagus sylvatica stands have developed from marlstones, sandstones, and limestones, and those under Pinus radiata stands from marlstones, sandstones and volcanic materials. On the other hand, most agricultural soils and those under Quercus ilex stands have developed from limestones. The soils were air-dried and passed through a 2-mm sieve prior to analysis. The oxidability of SOC by permanganate in the Fagus sylvatica forest soils was determined with 33 mM KMnO4 after different incubation times (1 h, 3 h, 6 h and 24 h), and that of the rest of the soils with the same reagent after 1 h incubation. For all soils, general soil properties (SOC, total N, pH, CEC, particle-size distribution) were determined. Analysis of SOC was carried out with (i) K2Cr2O7, following the Walkey-Black method, and (ii) a LECO C analyzer (corrected for carbonates when present). The Fourier transform infrared spectra of untreated soil samples were also obtained. The pH values of soils under Fagus sylvatica stands ranged between 4.0 and 8.2, those of under Pinus radiata stands between 4.0 and 7.5, and those under Quercus ilex stands between 4.3 and 8.5, whereas the pH range of the agricultural soils studied was narrower (7.6-8.4). The organic C data corresponding to the soil samples is currently being analyzed.
Capalbo, Susan (Montana State
University, Dept. of Agricultural Economics and Economics, Bozeman, MT,
59717-2920; Phone: 406-994-5619; Fax: 406-994-4838; Email: scapalbo@montana.edu)
Estimating the Economic Potential for Agricultural Soil Carbon Sequestration in the Central U.S. Using an Aggregate Econometric-Process Simulation Model
J. Antle, S. Capalbo*, K. Paustian
As the scientific evidence
supporting the hypothesis of anthropogenic global warming and climate change
has grown, so has the demand for viable greenhouse gas (GHG) mitigation
strategies. Research has shown that agricultural GHG mitigation could offset a
relatively small proportion of total U.S. emissions and that agricultural soil
carbon sequestration could be cost effective. Studies of economic potential for
soil carbon sequestration conducted to date have been based on either
field-scale economic simulation models covering relatively small regions where
such data are available (e.g., cites) or on sectoral models. However,
site-specific field-scale or farm-scale data are not generally available for
large regions of the U.S. and other countries; nor are the data and parameters
available to implement sectoral models for many regions of the world.
Consequently, analysis of economic potential for agricultural soil carbon
sequestration has been limited to selected regions within the U.S. and for
selected sectors. The purpose of this paper is to develop and apply a method to
assess economic potential for agricultural GHG mitigation that can be
implemented using existing secondary data, such as the agricultural census data
available in the U.S. and many other regions of the world, combined with
widely-available estimates of soil carbon stocks derived from biophysical
simulation models such as Century (cites) or from simpler estimation methods.
This economic methodology utilizes the principle of opportunity cost on which
detailed micro-economic analysis of agricultural GHG mitigation potential is
also based. However, in place of simulation models based on site-specific
field-level or farm-level data, the method proposed here is based on the
estimation of conventional econometric profit function models with agricultural
census data aggregated to the county scale for a region such as the central
U.S. We also use this model to investigate the importance of two issues that
have been identified as potentially critical in the assessment of carbon
sequestration potential, namely the impact of spatial scale at which carbon
stocks and changes are estimated, and the effects of transaction costs on
economic feasibility of soil carbon sequestration contracts. Simulations for
the central U.S. show that reduction in fallow and conservation tillage
adoption in the wheat system could generate up to about 1.7 million MgC/yr,
whereas increased adoption of conservation tillage in the corn-soy-feed system
could generate up to about 6.2 million MgC/yr at a price of $200/MgC. Due to
the relatively high price elasticity of response, at least half of this
potential could be achieved at relatively low carbon prices (less than $100 per
ton). The aggregate econometric-process model used in this analysis was found
to produce estimates of economic potential for soil carbon sequestration
potential similar to results produced by much more data-intensive, field-scale
models. This result suggests that this simpler, aggregate modeling approach can
produce credible estimates of soil carbon sequestration potential.
Carlisle, Eli (Univeristy of
California-Davis, Dept. of Viticulture, Davis, CA, 95616; Phone: 530-754-7144;
Email: ecarlisle@ucdavis.edu)
Conversion of Oak Woodlands to Vineyards Alters Physical Constraints on Soil CO2 Respiration in a Mediterranean Climate Ecosystem
E.A. Carlisle*, K.L. Steenwerth, D.R. Smart
We examined constraints on annual soil CO2 respiration at unmanaged oak woodlands and adjacent vineyards that were converted from oak woodlands approximately 30 years ago in the Oakville Region of Napa Valley, California. All sites were located on the same soil type, a Bale (variant) gravelly loam (Fine-loamy, mixed, superactive, thermic Cumulic Ultic Haploxeroll) and dominated by C3 vegetation. Seasonal soil CO2 efflux was greatest at the oak woodland sites, although during the dry summer periods the rates measured from oak sites were at times similar to those measured from vineyards. In spite of the fact that CO2 efflux rates were higher, soil profile CO2 concentrations were lower at the oak-woodland sites, except at the shallowest depth (15 cm). Soil gas diffusion coefficients for the oak sites were larger than for the vineyard sites. Long-term annual cultivation of the vineyard soils apparently increased bulk density, diminished porosity, and thus altered the effective gas diffusivities. In addition to lower CO2 production, lower diffusion coefficients may help account for the lower rates of CO2 efflux and higher CO2 concentrations in vineyard soil profiles. Vineyard soil CO2 was more depleted in 13C throughout the soil profile below 30 cm as indicated by more negative d13C ratios, and points to different respiratory C sources in vineyard soils. Annual C losses were less from the vineyard soils (7.02 ± 0.58 Mg C ha-1 yr-1) as compared to the oak soils (15.67 ± 1.44 Mg C ha-1 yr-1), and both were comparable to losses reported in previous investigations.
Chang, Chi (AAFC, Lethbridge, AlbertaLethbridge Research Centre, Agriculture and Agri-Food, Lethbridge, AB, T1J 4B1, Canada; Phone: 403 317-2220; Fax: 403 317-2187; Email: chang@agr.gc.ca)
C. Chang*, X. Hao, G. Clayton
Animal manure application to land has been shown to increase soil organic carbon content and changes in soil physical, chemical, and biological properties. Land application of animal manure, either in raw or composted form, is also considered part of strategies for C-sequestration. However, the rates of change in soil organic C content (concentration) and the rates of increase in the total amount of soil organic C accumulation in the soil profile in relation to the total cumulative amount of organic C applied through feedlot cattle manure application are not well known. A long-term cattle feedlot manure land application field study was initiated in the fall, 1973 in Lethbridge Alberta, Canada. The annual manure application rates were 0, 30, 60 and 90 Mg ha-1 for nonirrigated and 0, 60, 120 and 180 Mg ha-1 (wet weight) for irrigated land. The results showed that soil organic C content (concentration) in the surface 15 cm of soil increased curve linearly with cumulative amount of organic-C applied through manuring under both non-irrigated and irrigated conditions. The total amount of soil organic C increase in the soil profile from 0 to 60 cm depth interval also increased with cumulative organic C applied. The rate of increase in surface soil organic C content and total amount of soil organic C in the profile can be calculated. This information is useful in evaluating C sequestration through long-term manure application.
Chen, Hua (School of Forestry and
Wildlife Sciences, Auburn University, Auburn, AL 36849, Phone: 334-844-1057; Fax: 334-844-1084; Email:
chenj@geog.utoronto.ca)
Effects of Cropland Abandonment and Forest Regrowth on
Terrestrial Carbon Storage in
Hua Chen*, Hanqin
Tian, Chi Zhang, Mingliang
Liu, Shufen Pan
Southeast is thought to be the largest carbon sink across the six major bioclimatic regions of the conterminous United States. Cropland abandonment and forest regrowth are two potentially important factors to be responsible for this carbon sink. The objective of this study is to examine how land uses change, especially cropland abandonment and forest regrowth, on terrestrial carbon storage in southeastern US. We have compiled and developed the historical annual cropland gridded data set of southeastern US between 1850 and 2000 with a spatial resolution of 4 km. This data set has been used as input of the Terrestrial Ecosystem Model (TEM) to simulate land use effects on carbon fluxes and storage in the region. According to the preliminary analysis, our results indicate that, from 1850 to 2000, cropland area decreased more than 50%, most of which was converted to forests. Our preliminary analysis indicates that forest regrowth after cropland abandonment has resulted in a carbon uptake in the southeast, and the magnitude of the carbon sink varies over space and time.
Chen, Jing M. (Department of Geography, University of Toronto, 100 St. George St., Toronto, Ontario, Canada, M5S 3G3; Phone: 416-978-7085; Fax: 416-946-3886; Email: chenj@geog.utoronto.ca)
Mapping Carbon Source
and Sink Distributions in Canada’s Forests and Wetlands Resulting from Disturbance
and Non-disturbance Effects
Jing M. Chen*,
Weimin Ju,
In collaboration with several federal government agencies and universities, annual spatial distributions of carbon sources and sinks in Canada’s forests and wetlands at 1 km resolution are computed for the period from 1901 to 1998 using ecosystem models that utilize remote sensing images and gridded climate, soils, and forest inventory data. GIS-based large fire polygons for most regions of Canada are used to develop a remote sensing algorithm for mapping and dating forest burned areas in the 25 years prior to 1998. These mapped and dated burned areas are used in combination with inventory data to produce a complete image of forest stand age in 1998. Empirical NPP-age relationships were used to simulate the annual variations of forest growth and carbon balance in 1 km pixels, each treated as a homogeneous forest stand. Annual CO2 flux data from five sites were used for model validation. The Integrated Terrestrial Ecosystem Carbon Cycle Model (InTEC) was developed (Chen et al., 2000) for this carbon source and sink mapping in annual time steps. This model is supplemented by a daily model named Boreal Ecosystem Productivity Simulator (BEPS) for detailed simulations in recent years (Liu et al., 2003). InTEC is recently expanded to include aerobic and anaerobic processes in wetlands, so that the total carbon absorption and release by CO2 and CH4 gases are also included. Both disturbance (fire, insect, harvest) and non-disturbance (climate, N, CO2) factors and their interactions are included the model. The significance of these new national statistics of the carbon budgets of Canada’s forests and wetlands will be discussed in comparison with previous results.
Cherney, Jerry (Cornell University, Dept. of Crop and Soil Sciences, 503 Bradfield Hall, Ithaca, NY, 14853; Phone: 607-255-0945; Fax: 607-255-2644; Email: jhc5@cornell.edu)
J.H. Cherney*, P.B. Woodbury, S.D. DeGloria
Use of herbaceous biomass for energy production can significantly reduce greenhouse gas emissions in the northeastern USA. Our objective was to evaluate the potential for grass production in New York State and to develop agronomic management strategies to improve the energy characteristics of this feedstock. The northeastern USA has a considerable acreage of unused or underutilized agricultural land. The estimated potential underutilized crop area in New York State is approximately 1.5 million acres, based on data from satellite imagery and the census of agriculture. Some of this land is reverting back to woody growth while some of it is in government programs. Much of this land has encountered difficulties growing row crops and is in some type of grassland. Almost all of this land could grow grass crops for bioenergy, regardless of how marginal the soils are for agricultural production. Potential yield estimates of 1.25 ton/acre unimproved grassland, and 2.5 ton/acre for managed switchgrass (Panicum virgatum L.) and reed canarygrass (Phalaris arundinacea L.) were selected as economic cutoff values for production of these crops. Based on these economic cutoffs reed canarygrass could be established on 96% of currently unused acreage, while switchgrass could be economically established on 80% of this acreage. Without any fertilization or other inputs approximately 81% of this unused land could be economically harvested once a year for biomass. Based on soil-specific predicted crop yields approximately 6 million tons of reed canarygrass could be produced on these lands in New York State. Ash con