Assessment of Soil Carbon in Forests, Plantations and Wastelands

Dr. M.N.Jha Forest Research Institute Dehra Dun

Workshop on “Forestry and Climate Change - Assessing Mitigation Potential and Costs” , Sept. 23 –24; 2002, India International Centre, New Delhi

SOC is the largest, ca 15X1014 kg Creservoir at the earth surface.

This reservoir responds positively to,

•Increased photosynthesis.

•Increased moisture.

•Directly to increased atmospheric CO2 by

decreasing the SOC decompositions rates.

•Increased temperature.

We have ignored SOC because we think it is dead biomass and is directly dependent on the amount of live biomass. It neglects following considerations :

A. Increased oxidation of SOC to CO2 by :

- Cultivation of new lands (reduces SOC by1/3and converts it to CO2)

- Increased temperature which accelerates SOC decay rates.

- Conversion of forests to other land uses.

- Decreased rainfall will convert SOC to CO2 by raising temperature and aerobiosis.

Conversely, soil can remove CO2 from atmosphere by:

B. Accumulating SOC beyond receiving increased NPP, via

- Increased rainfall which lowers soil temperature and decreases O2 diffusion rates thereby reducing oxidation rates.

- Minimum-or no-tillage agriculture which should increase SOC.

- Increasing atmosphere CO2 can repress SOC degradation rates.

How might soil be affected by climate changes.

Changing temperature Altered rate of microbial activity in soil

Will cause break down of organic matter at faster rates

Will result in greater release of CO 2

Carbon Stored in :

Atmosphere 1 unit

Soil 2 units

Therefore, change in temperature and increased microbial activity can lead to significant increase of CO2 in atmosphere

Soil organic carbon in plantations and natural forests• Plantation: Soil Organic C (up to 30

cm depth)

(age 16 years) (t/ha)• Teak 68.0• Chir pine 57.2• Eucalyptus 99.6• Khair 79.6• Shisham 98.4

• Natural Forests:• Deodar 392.0• Chirpine 338.8• Spruce 280.0• Kail 272.8• Quercus 360.0

Organic carbon store in some Indian Soils (up to 30 cm depth)

Area SOC store Total SOC

Store

(m ha) (t/ha) (Gt)

•Red soil 117.2 41.2 4.80

•Laterite 11.7 120.4 1.40

•Alluvial 58.4 32.4 1.90

•Brown Forest 21.3 190.0 4.00

•Saline/alkali 10.0 13.2 0.13

•Black 64.5 18.0 1.10

Soil organic carbon store under different land uses in India

Land use Area Organic C Store (up 30 cm depth)

(m ha) (t/ ha ) Total

Store (G t)

Forests 75.00 120.0 9.00

Agriculture 150.00 40.0 6.00

Pastures 11.80 40.0 0.44

Barren land 18.97 20.0 0.37

GHG mitigation potential of different land uses with barren land as base.

Land use SOC store Mitigation potential (up to 30 cm depth)

1. Barren land 20.0 t / ha 1.00

2. Pasture 40.0 t / ha 2.00

3. Agriculture66.0 t / ha 3.30

4. Plantations 80.5 t / ha 4.02

5. Agroforestry 83.6 t / ha 4.18

6. Forest 120.0 t / ha 6.00

Carbon sequestration in the wasteland and improvement after afforestationC store (t/ha) C store

(No afforestn.) (after 9 yrs. of afforestn.)

C store (t/ha) % increase

19.46 68.80 253.14

Species: Dalbergia sissoo, Prosopis juliflora, Eucalyptus hybrid

Site : Eastern U.P.

Sink Expansion Potential of Sodic Wastelands

Sink expansion potential (m t) after

3 years 6 years 9 years

Prosopis 49.6 112.0 252.8

Eucalyptus 28.8 83.2 179.2

Dalbergia 11.2 52.8 158.4

Soil Carbon Estimates in Forest SoilsForest/Strata Soil Org. C store (m t)

1984 1994 Change

Conifers 943.70 969.95 26.25

Teak 765.64 755.09 - 10.55

Sal 905.46 899.86 - 5.60

Bamboo 182.53 181.22 - 1.31

Mangrove 35.86 39.23 3.37

Hollong 0.92 0.82 - 0.10

Khasi pine 17.41 17.30 - 0.11

Salai 13.79 13.93 0.14

Khair 10.86 10.45 - 0.41

Misc. 6555.60 6469.80 - 85.80 - ve changes in SC store has been due to – ve change in the area under different species

except in conifers, Mangrove and Salai

Source of Soil Carbon estimates

The SOC estimates are based on,

- published Indian literature mainly on the work of

- FRI, Dehra Dun and sister institutions under ICFRE

- other research organizations

Proposal

There is a need to formulate a strategy for more precise SOC estimates and monitoring thereafter under different forest covers and also under trees outside forest (TOF) etc.

Approach

A joint field programme with Forest Survey of India for precise SOC estimates and monitoring, ensuring full correspondence between forest cover and land area.

Strategy

- FSI Survey methodology

- SOC estimates and monitoring as programmed by FSI for forest cover & TOF

- Soil sampling and carbon estimations as per IPCC guidelines