Study on Carbon Budget for Ecosystems
of China: Aspects and Progress
Yao Huang
([email protected])
Institute of Atmospheric Physics
Chinese Academy of Sciences
SCIENTIFIC THEMES
FOR CHINESE SCIENTISTS
1. How do C sources and sinks vary over
time for different ecosystems?
2. How do patterns of C sources and sinks
distribute regionally?
3. Key factors driving the processes of C
cycling in different ecosystems?
SCIENTIFIC THEMES
FOR CHINESE SCIENTISTS
4. Responses of different ecosystems to the
global change?
5. Options that can enhance the C storage
and/or reduce the C emissions from
different ecosystems?
Projects
• Study on Carbon Budget in Terrestrial and
Marginal Sea Ecosystems of China, CBTSEC
launched by the Chinese Academy of Sciences
(2001~2005)
• Carbon Cycle and Driving Mechanisms in
China Terrestrial Ecosystems, CCDMCTE
supported by the Ministry of Science and
Technology of China (2003~2007)
Objectives of the CBTSEC
1. To clarify the characteristics of C
fluxes and reservoirs for different
ecosystems
2. To address the role of climate, soil and
human actions playing in the
terrestrial C cycling processes
3. To compile an inventory of current C
budget regarding to the terrestrial
ecosystems of China
4. To evaluate the potential response of
ecosystems to projected global change
5. To assess the contribution of land-use
and land-cover change (LUCC) to C
sink/source relationship during the last
100-year period
6. To develop techniques that can enhance
the C storage and/or reduce C emissions
I: Measurements of C fluxes and reservoirs
（Eddy covariance, Static chamber/GC system, RS)
Characteristics of C fluxes and reservoirs
for typical ecosystems
III: History of C
cycling: LUCC
II: Biogeochemical processes of
C cycling:
Responses of C cycling to climate,
soil and human activities
IV: C Model:
Assimilation &
Respiration
V: Patterns of C sources/ sinks and options
1. Seasonal variation of C sources/sinks: Model output
2. Regional distribution of C sources/sinks: Model + GIS + RS output
3. Response of ecosystems to projected global change: C-model+GCM+GIS output
4. Potential in enhancing C storage
5. Options for mitigating C emissions and/or enhancing C storage
Framework of the CBTSEC
Topics and Progress of the
CBTSEC
1 Carbon fluxes and reservoirs in typical Chinese
terrestrial and marginal sea ecosystems
Key aspects:
Observations and measurements in situ
 Eddy covariance
 Static chamber/GC system
 Remote sensing
Establishment of ChinaFlux network
Eddy covariance, Static Chamber/GC, Remote Sensing
Observations and measurements in situ
(Eddy Covariance)
40
Higher NEE in
forest
30
20
10
Temperate conifer-broadleaved
forest (42°24’N, 128°28’E,
763m)
0
-10
-20
-30
Jul-02
Oct-02
Jan-03
May-03 Aug-03
Nov-03
Mar-04
Jun-04
Sep-04
30
Higher NEE in
cropland
20
10
0
-10
-20
-30
-40
-50
Cropland (36°57’N, 116°36’E,
20m)
Jan-03
May-03
Aug-03
Nov-03
Mar-04
-60
Oct-02
Jun-04
Sep-04
10
Lower NEE in
high-frigid brush
5
0
-5
-10
-15
High-frigid brush (37°45’N, 101°12’E,
3200m)
Jan-03
May-03
Aug-03
Nov-03
Mar-04
Jun-04
-20
Oct-02
Sep-04
Observations and
measurements in
situ
Static chamber
Soil respiration (mgCO 2/m 2/hr)
Respiration from forest soil is higher than
that from soils of cropland and grassland
900
Forest
800
Cropland
700
Grassland
600
500
400
300
200
100
0
07-03-02
10-01-02
12-30-02
03-30-03
06-28-03
Date (mm-dd-yy)
09-26-03
12-25-03
03-24-04
Increased atmospheric CO2 concentration
enhanced CH4 emission from rice paddy
FACE
Ambient
CO2
100
常绿针叶
50
落叶针叶
针阔混交
常绿阔叶
落叶阔叶
草地
0
灌丛
荒漠
农田
无植被
Percentage of land cover from RS
750
Identification of land cover
from RS
375
0
Annual NPP from RS
2 Biogeochemical processes of C cycling
in different ecosystems of China
Key aspects:
 Decomposition and retention of the litter-C in
forest ecosystems as influenced by climate
 Processes of C cycling in typical pasture
ecosystems such as temperate grass and highfrigid meadow grass
 Key factors and mechanisms regulating organic C
balance in agricultural soils
Carbon released from litter decomposition
accounted for ~30% of soil respiration in
temperate conifer-broadleaved forest
Partition of net
photosynthesis (%)
Some 17% of net photosynthesis of
maize and soybean is released through
rhizospheric respiration
100
80
60
40
20
0
Aboveground-C
Root-C
Soil-C
Component
Rhizospheric
Resp-C
35
wheat
rice
25
-1
-1
Rd (µmol kg s )
30
20
15
10
R d = 4.74(0.36)N - 1.45
(R 2 = 0.83, n =152)
5
0
0
2
4
6
8
N (%)
Crop dark respiration increased with
tissue N concentration
Plant root contributes greatly
to soil carbon in grassland
3 Patterns of C sinks and sources and the
response to global change
Key aspects:
 Modeling C emission/assimilation
 Integration of C models with GCMs, GIS and
RS
 Geographical and temporal patterns of C
sources and sinks
 Response of different ecosystems to the global
change
Models are developed for the
sections of forest, grassland,
cropland and wetland,
respectively.
Upscaling: integration of models
and GIS and RS
Upscaling: daily weather (10km× 10km）
Upscaling: soil parameter (10km× 10km）
Upscaling: cropping system (10km×10km）
4 LUCC and mitigation options
Key aspects:
Contribution of LUCC to the C cycling
Options for mitigating C emissions
and/or enhancing C storage
Arable land increased from 1661
to 1950 while decreased thereafter
110
Average CLAI
105
100
95
90
85
80
75
70
1650 1700 1750 1800 1850 1900 1950 2000
Year
Contribution to SOC(%)
There is a great potential for enhancing C
storage in agricultural soils
60
50
40
30
20
10
0
synthetic
fertilizer
crop straw
amendment
no-tillage
Agricultural practice
16
18
Fengqiu
(after12-year)
12
10
16
14
SOM（g kg-1)
SOM (g kg-1)
14
8
6
4
12
Yingtan
(after14-year)
10
8
6
4
2
2
0
0
1/2OM
CK
NK
NP
Treatment
NPK
OM
PK
Original
CK
NK
PK
Treatment
NP
NPK
Institutes are involved in the CBTSEC
 Institute of geography
science and resource
 Institute of Atmospheric
Physics
 Institute of Applied Ecology
 Institute of Soil Sciences
 Institute of Botany Sciences
 Institute of Remote Sensing
 Center of Ecology and
Environment Sciences
 Chinese Ecosystem
Research Network
 …
Thank You