Study on Carbon Budget for Ecosystems of China: Aspects and Progress

Yao Huang(huangy@mail.iap.ac.cn)

Institute of Atmospheric PhysicsChinese Academy of Sciences

20th SC-IGBP Meeting, Feb. 19~23, 2005, Beijing

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, CBTSEClaunched by the Chinese Academy of Sciences (2001~2005)

• Carbon Cycle and Driving Mechanisms in China Terrestrial Ecosystems, CCDMCTEsupported 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 reservoirsfor typical ecosystems

I: Measurements of C fluxes and reservoirs（Eddy covariance, Static chamber/GC system, RS)

Characteristics of C fluxes and reservoirsfor typical ecosystems

III: History of C

cycling: LUCCIII: History of C

cycling: LUCC

II: Biogeochemical processes of C cycling:

Responses of C cycling to climate, soil and human activities

II: Biogeochemical processes of C cycling:

Responses of C cycling to climate, soil and human activities

IV: C Model:Assimilation &

Respiration

IV: C Model:Assimilation &

Respiration

V: Patterns of C sources/ sinks and options1. Seasonal variation of C sources/sinks: Model output2. Regional distribution of C sources/sinks: Model + GIS + RS output3. Response of ecosystems to projected global change: C-model+GCM+GIS output4. Potential in enhancing C storage5. Options for mitigating C emissions and/or enhancing C storage

V: Patterns of C sources/ sinks and options1. Seasonal variation of C sources/sinks: 1. Seasonal variation of C sources/sinks: Model output2. Regional distribution of C sources/sinks: 2. Regional distribution of C sources/sinks: Model + GIS + RS output3. Response of ecosystems to projected global change: 3. Response of ecosystems to projected global change: C-model+GCM+GIS output4. Potential in enhancing C storage4. Potential in enhancing C storage5. Options for mitigating C emissions and/or enhancing C storage5. Options for mitigating C emissions and/or enhancing C storage

Framework of the CBTSECFramework of the CBTSECFramework 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 networkEddy covariance, Static Chamber/GC, Remote Sensing

Observations and measurements in situ(Eddy Covariance)

-30

-20

-10

0

10

20

30

40

Ju l-02 O c t -02 Ja n -03 M a y -03 A u g -03 N o v -03 M a r-04 J u n -04 S e p -04

Temperate conifer-broadleaved forest (42°24’N, 128°28’E, 763m)Higher NEE in

forest

-60

-50

-40

-30

-20

-10

0

10

20

30

O c t -02 J a n -03 M a y -03 A u g -03 N o v -03 M a r-04 J u n -04 S e p -04

Cropland (36°57’N, 116°36’E, 20m)

Higher NEE in cropland

-20

-15

-10

-5

0

5

10

O c t -02 J a n -03 M a y -03 A u g -03 N o v -03 M a r-04 J u n -04 S e p -04

High-frigid brush (37°45’N, 101°12’E, 3200m)

Lower NEE in high-frigid brush

Observations and measurements in situ

Static chamber

Respiration from forest soil is higher than that from soils of cropland and grassland

0100

200300400

500600700

800900

07-03-02 10-01-02 12-30-02 03-30-03 06-28-03 09-26-03 12-25-03 03-24-04

Date (mm-dd-yy)

Soi

l res

pira

tion

(mgC

O2/

m2 /h

r) ForestCroplandGrassland

Increased atmospheric CO2 concentration enhanced CH4 emission from rice paddy

FACE

Ambient CO2

0

100

50

Percentage of land cover from RS

常绿针叶

落叶针叶

针阔混交

常绿阔叶

落叶阔叶

草地

灌丛

荒漠

农田

无植被

Identification of land cover from RS

0

750

375

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 high-frigid 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

Some 17% of net photosynthesis of maize and soybean is released through rhizospheric respiration

0

20

40

60

80

100

Aboveground-C Root-C Soil-C RhizosphericResp-C

Component

Par

titio

n of

net

phot

osyn

thes

is (%

)

R d = 4.74(0.36)N - 1.45(R 2 = 0.83, n =152)

0

5

10

15

20

25

30

35

0 2 4 6 8

N (%)

R d (µ

mol

kg-1

s-1

)

wheatrice

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 optionsKey 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

1650 1700 1750 1800 1850 1900 1950 200070

75

80

85

90

95

100

105

110A

vera

ge C

LAI

Year

There is a great potential for enhancing C storage in agricultural soils

0102030405060

syntheticfertilizer

crop strawamendment

no-tillage

Agricultural practice

Con

tribu

tion

to S

OC

(%)

0

2

4

6

8

10

12

14

16

1/2OM CK NK NP NPK OM PK

Treatment

SO

M (g

kg-1

)

02468

1012141618

Original CK NK PK NP NPK

Treatment

SOM（

g kg

-1)

Fengqiu(after12-year)

Yingtan (after14-year)

Institutes are involved in the CBTSEC

Institute of geography science and resourceInstitute of Atmospheric PhysicsInstitute of Applied EcologyInstitute of Soil SciencesInstitute of Botany SciencesInstitute of Remote Sensing Center of Ecology and Environment SciencesChinese Ecosystem Research Network…

Thank You