INTENSIVE TILLAGE AS A MECHANISM FOR CO2 EMISSION FROM AGRICULTURAL SOILS
Description: Agricultural ecosystems can play a significant
role in production and consumption of greenhouse gases, specifically, carbon
dioxide (CO2). Information is
needed on the mechanism and magnitude of gas generation and emission from
agricultural soils with specific emphasis on tillage mechanisms. This work
reviews effect of different tillage methods on the short-term CO2
and H2O vapor flux from clay loam soils high in soil organic carbon
(C) in the northern corn belt of the U.S. [Reicosky
and Lindstrom, 1993, 1995; Reicosky,
1997, 1998]. The soil CO2 flux was measured one minute after the
tillage using a large, portable chamber as described by Reicosky and Lindstrom [1993]. The four tillage methods were
moldboard plow (MP) only, moldboard plow plus disk harrow twice, disk harrow
and chisel plow using standard tillage equipment following a wheat (T. Aestivum
L) crop compared with no tillage (NT).
Author's Names: D.C. Reicosky
Filesize: 26.51 Kb
Added on: 03-Aug-2005 Downloads: 21
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SOIL CARBON IN ABANDONED LANDS OF RUSSIA
Description:
Annual
changes in soil carbon stock are considered of the abandoned managed
agricultural lands that were under natural regrowth over the territory of Russia
within the period 1990-2002. Total area of abandoned agricultural land is 21,6
millions ha. The projections of changes in the carbon stock have been made for
the period from present to 2010. The ROTHC model was employed in the
investigation of carbon dynamics in soils. The territory of Russia
was subdivided into 40 regions. The average basic soil and climatic parameters,
as well as the annual input of organic matter into soils due to natural
succession were estimated for each region. Average annual net-emission over the
territory of abandoned lands was 2,1 ± 1,8 Tg C/yr in 1990-1999. CO2
removal from the atmosphere by soils was 5,2 ± 2,8 Tg C/yr on average in
2000-2002. A total increase in carbon stock of the abandoned lands over the
country can be as high as 153 Tg C (that corresponds to the removal of 561 Tg
of CO2 from the atmosphere) in 2010. Central regions of the European
part of Russia, south of
East Siberia and the Far East will have the
highest intensity of carbon sequestration.
Author's Names: A.A. Romanovskaya
Filesize: 36.11 Kb
Added on: 04-Aug-2005 Downloads: 22
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ANNUAL CARBON DIOXIDE DRAWDOWN AND THE NORTHERN ANNULAR MODE
Description:
Year-to-year variations in summer drawdown of northern
hemisphere atmospheric carbon dioxide (CO2) are compared with
corresponding year-to-year variations in sea- level pressure (SLP), surface air
temperature and the productivity of land vegetation as inferred from the
satellite-derived normalized difference vegetation index (NDVI). Annual values
of CO2 drawdown for the years 1980-2000 are estimated from smoothed
time series derived directly from individual flask samples at the 9 northern
hemisphere monitoring stations with the most continuous records. The leading
principal component of the 9 standardized drawdown time series, in which all
stations exhibit positive loadings, is used to represent the hemispheric signal
in the CO2 drawdown. Linear regression analysis is used to infer the
spatial patterns of anomalies in sea level pressure, surface air temperature
and the NDVI observed during various seasons of years in which the drawdown is
anomalously strong.
Author's Names: J.L. Russell, E. Shevliakova, S. Malyshev, and J.M. Wallace
Filesize: 13.09 Kb
Added on: 04-Aug-2005 Downloads: 42
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SEASONAL CHANGE OF CO2 FLUX ABOVE A JAPANESE BEECH FOREST
Description:
Forestry
and Forest Products Research Institute erected a CO2 flux observation
tower at a Japanese beech forest, and have measured CO2 flux with
closed-pass eddy covariance method for 5 years. During the observation period, 2003
was the most CO2 absorbed year, and the amount was 1.9 times larger
than 2004, which was the least CO2 absorbed year. To investigate the
cause of the smaller CO2 absorption in 2004, we referred some
meteorological factors in 2003 and 2004.
Solar radiation (during green-leaved season) was larger in 2004 than
2003, in contradiction to CO2 absorption. On the other, air temperature was higher in 2004
than 2003 (both in green-leaved and defoliated season). We assumed that larger
respiration in 2004 effected the depression of annual CO2
absorption. At our research site, annual
mean air temperature in 2004 was 0.95 degree centigrade warmer than 2003. The result of this study suggests the
tendency that warmer climate may cause less CO2 absorption in this
Japanese beech forest.
Author's Names: T. Saito, Y. Ohtani, Y. Mizoguchi, T. Morisawa
Filesize: 84.05 Kb
Added on: 04-Aug-2005 Downloads: 20
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FEASIBILITY OF EDDY COVARIANCE MEASUREMENTS OF THE ISOTOPIC COMPOSITION OF CO2 FLUXES ABOVE A ...
Description:
Better
quantification of atmosphere-ecosystem exchange of the isotopologues of CO2
could substantially improve our ability to probe underlying physiological and
ecological mechanisms controlling ecosystem carbon exchange, but the ability to
make long-term continuous measurements of the isotopic composition of exchange
fluxes has been limited by measurement difficulties. Quantum cascade (QC)
lasers are a new generation of infrared light sources that offer increased
stability and power for absorption spectroscopy applications (including the
measurement of isotope ratios in atmospheric CO2) and promise
substantial improvements over existing instruments: smaller size, increased
robustness, and most significantly for remote or long-term field deployments,
no need for cryogenic cooling of laser or detectors.
Author's Names: S.R. Saleska, J.H. Shorter, S. Herndon, et al
Filesize: 20.54 Kb
Added on: 04-Aug-2005 Downloads: 21
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THE EFFECTS OF LAND USE CHANGE AND OF SEASONAL VARIATIONS IN CLIMATE ON GPP ACROSS THE ...
Description:
Amazonian
forests play an important and complex role in the global carbon cycle,
contributing substantially to increases (via land use change emissions) and
possibly to net sequestration (in intact forests) of atmospheric CO2.
Predicting these processes of net carbon uptake and release depends crucially
on understanding ecosystem response to both seasonal and interannual
variations. However, prominent ecosystem modeling studies of the Amazonian
carbon cycle [Tian et al., 1998; Botta 2002] appear to make seasonal
predictions (wet-season carbon uptake and dry-season loss) at odds with both
some site-specific observations (which show the opposite pattern, Saleska et al., [2003]) and basin-wide
satellite observations (which imply large-scale increases in the activity of
photosynthetic vegetation during the dry season, Huete et al., [2005]).
Author's Names: S. R. Saleska, M. Pathmadevan, A. Huete, F. Cardoso, et al
Filesize: 19.68 Kb
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PARTITIONING OF ROOT AND MICROBIAL RESPIRATION IN SOIL: COMPARISON OF THREE METHODS
Description:
Three techniques for separation of total CO2 efflux from soil
into root and microbial respiration were compared: component integration, root
exclusion and pulse labelling of shoots in 14CO2
atmosphere. The contribution of rhizosphere to total CO2 efflux from
soil varied from 19 to 49% (including root respiration amounted to 9-32%). The
share of non-rhizosphere respiration was 51-80%. The results obtained by
component integration and root exclusion techniques were similar. Rhizosphere
respiration estimated by pulse labelling were less as estimated by two
non-isotopic methods.
Author's Names: D.V. Sapronov, Y. Kuzyakov
Filesize: 145.98 Kb
Added on: 04-Aug-2005 Downloads: 29
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ESTIMATING AND EVALUATING TERRESTRIAL CARBON FLUXES USING A BIOSPHERE MODEL IN TOKAI REGION
Description: Terrestrial carbon
fluxes are an important factor for the studies of global warming. This study
focuses on estimating a fluctuation
of the terrestrial carbon fluxes in the
Tokai region, Japan.
The local biosphere model used calculates carbon, water, and heat fluxes, and
required some climate and vegetation parameters as inputs. The model was
operated in 2000-2004 using meteorological data and MODIS data products.
We estimated spatial distributions in heat
and carbon fluxes at spatial resolution of 1*1 km, and validated an
adaptability of the model using measured data at the Takayama flux-site. As a
result, estimated GPP and heat fluxes had a good relationship to measured data.
We can precisely check on the accuracy of the model to estimate the
spatial and temporal patterns of the terrestrial carbon fluxes.
Author's Names: T. Sasai, K. Okamoto, K. Murakami, and Y. Yamaguchi
Filesize: 162.38 Kb
Added on: 04-Aug-2005 Downloads: 24
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INFERRING FLUXES OF BIOMASS BURNING FROM A GLOBAL CARBON CYCLE DATA ASSIMILATION SYSTEM
Description: The Carbon Cycle Data Assimilation System (CCDAS) infers
values of the parameters controlling the function of a process model of the
terrestrial biosphere using various observations. An obvious restriction of
this approach is the limitation by the dynamics of the underlying process model.
Careful study of the model-data mismatch and analysis of residuals can alert us
to the presence of systematic errors which then candidate processes to extend the
terrestrial biosphere model and the assimilation system. In a previous study, Rayner et al. [2005] noticed systematic underestimate of
carbon release events in the tropics. The most likely explanation for this was
the absence of any model of biomass burning in the biosphere model used in that
study. Here, we extend CCDAS to infer the spatial and temporal patterns of
biomass burning in the period 1979-1999. In a first attempt we include some
flux components to account for missing processes. This so-called weak
constraint form avoids biasing the inferences since the underlying model is no
longer forced to match data without necessary processes. Also the magnitudes of
the extra inferred fluxes quantify the missing processes.
Author's Names: M. Scholze, P. Rayner, W. Knorr, T. Kaminski, et al
Filesize: 12.15 Kb
Added on: 04-Aug-2005 Downloads: 21
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NEW ESTIMATES OF LIVE BIOMASS AND NET PRIMARY PRODUCTION OF RUSSIAN FORESTS: A FOOTPRINT OF ...
Description: The
paper presents new estimates of live biomass (phytomass) and net primary production
(NPP) of Russian forests for 1993 and 2003. These indicators are estimated
based on forest inventory data and a specially developed semi-empirical modeling
system. The latter contains regional
models of growth by major forest forming species, multi-dimensional models of
phytomass and models of biological production. It is shown that the fractional
structure of forest phytomass substantially differs from previous estimates
that indicated significant temporal trends of the share of aboveground wood
(AGW), green part (GP) and belowground (BG) phytomass. The total forest NPP (of
307 g C m-2yr-1 for 2003) is substantially higher than
previously reported. These changes may
be attributed to climatic change which was dramatic over the last four decades,
particularly in Asian Russia.
Author's Names: A. Shvidenko, D. Shepashenko, S. Nilsson, and A. Lapenis
Filesize: 41.29 Kb
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