Soil Carbon Sequestration and Greenhouse Gases Mitigation in Selected Ecosystems in the

Rodolfo O. Ilao1 , Edilberto D. Salang2 and Januel P. Floresca3 1Director, Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCARRD) 2Associate Professor, Western Mindanao State University (MSU), Zamboanga City, Philippines 3Instructor, Isabela, State Univeristy (ISU), Echague, Isabela, Philippines Tanay, General Nakar,

Mt. Makiling, Abra Kalinga-Apayao Ilocos Sur Mt. Prov. Ifugao La Union SOIL CARBON Nueva Vizcaya

Sub-Prov. of Aurora SEQUESTRATION IN Pampanga

Rizal

Cavite Laguna Catanduanes SELECTED Isabela Camarines Sur Marinduque ECOSYSTEMS IN THE

Eastern Verde Island Samar Passage, Batangas Leyte PHILIPPINES Guimaras

Brgy. Catmon,

Batangas Agusan del Sur Zamboanga Bukidnon de Norte Zamboanga del Sur Davao del Norte North Cotabato Davao Compostela City Valley

South Cotabato General. Santos City SOIL CARBON SEQUESTRATION

Brushlands Grasslands Secondary forests

Degraded pasturelands Mangroves Factors affecting SOC Secondary sequestration in the Forests Philippines: 1. Natural factors • Clima te – lililarge soil organic carbon (SOC) is associated with higher precipitation • Topography – higher SOC is found in higher elevation areas • Natural disturbance 2. Anthropogenic Secondary Forests

Carbon density in biomass and soil in the secondary forests Carbon Density (Mg/ha) Sik/ink/carb on pool General Nakar, Quezon Tanay, Rizal Trees > 10cm dbh 64.04 (42%)34.12 (37%) Understory/litter 1.58 (1%) 3.74 (4%) Soil 84.72 (57%)53.22(59%) Total 150.34 (100%) 91.08 (100%) Secondary Forests

LEGEND:

100 Trees >10cm dbh 90 84.72 80 Understorey/litter 70 64.04 60 C/haC/ha 53.22 Soil ggC/ha ggC/ha 50

MMMMMMMM 40 34.12 30 20 10 1581.58 3.74 5 Gen. Nakar Tanay

Carbon density in biomass and soil in the secondary forests Brushland and Grassland

Carbon density of the different land use types. types. Sink/carbon pool Carbon density (Mg/ha) Brushland Grassland Brush 14.73 (20%) Grass 2.49 (3%) 2.57 (4%) Soil 57.05 (()77%) 55.00 (()96%) Total 74.27 (100%)57.57 (100%) Brushland and Grassland

LEGEND: 80 Brush 70

60 Grass 57.05 55 50 Soil 40

30

20 14.73 10 2.49 2.57 5 Brushland Grassland

Carbon density of the different land use types Mangrove

Carbon pool status, biomass and carbon density distribution in mangrove ecosystem Sink/carbon pool Carbon density (Mg/ha) Verde Passage BrgyBrgy..CatmonCatmon Biomass 103.50 (90%) 125.79 (89%) Soil 11.95 (10%)15.92 (11%) Total 115.45 (100%) 141.71 (100%) Mangrove

LEGEND: 125.79 103.5 100 Biomass 90 80 Soil 70

C/ha 60 l ggC/ha 50 MMMM 40 30 15.92 20 11.95 10 5

Verde Passage Brgy. Catmon

Carbon pool status, biomass and carbon density distribution in mangrove ecosystem Degraded pastureland

Degraded pastureland with kakawate, kakawate,mahogany, and yemane stands Sink/carbon pool Carbon density (Mg/ha) Kakawate Mahogany Yemane Tree bbiomassiomass16.41 (21.04%)29.35 (35.82%)101.16 (66.96%) Understorey 1331.33 (1.7%) 0750.75 (0.92%) 0910.91 (0.63%) Litter 0.48 (0.62%) 0.01 (0.01%) 1.71 (1.18%) Soil 58.81 (76.35%)51.84 (63.27%)41.42 (28.53%) Total 77.03 (100%)81.94 (100%)145.21 (100%) Degraded pastureland 01.1601.16

1111 LEGEND: 100

90 Tree biomass

80 Understorey 70 C/ha 60 58.8158.81 Litter ggC/ha 22 51.8451.84 4444 MMMM 50 41. 41. Soil 40

30 29.3529.35 6.416.41

20 11

10 1.711.71 0.910.91 1.331.33 0.750.75 0.010.01 5 0.480.48 KkKakawa te MhMahogany Yemane Carbon pool status, biomass and carbon density distribution in mangrove ecosystem Agroforestry Carbon status in degraded pastureland planted to fast ‐growing tree species Sink/carbon pool Carbon density (Mg/ha) Gmelina‐cacao multistorey Alley cropping system Gmelina arborea 106.62 Theobroma cacao 8.33 Understorey 0280.28 Necromass 0.99 Roots 0.24 Gliricidia sepium Biomass total 116.46 1.69 Soil 68.12 91.96 Total 184.58 93.25 Agroforestry LEGEND: Gmelina arborea 06.6206.62 6666 100 1111 Theobroma cacao 91.991.9 90 Understorey 80 2222 70 Necromass 68.168.1 60

C/haC/ha Roots gggg 50 MM 40 Gliricidia sepium 30

20 33 Biomass Total 8.38.3 10 0.990.99

0.280.28 Soil 1.691.69 5 0.240.24 GliGmelina-cacao multis torey Alley cropp ing sys tem Carbon pool status, biomass and carbon density distribution in mangrove ecosystem Carbon levels in selected ecosystems

LEGEND:

92 Forest 100 85 90 Brushland

80 68 Grassland

C/ha 70

ggC/ha 52 54

MMMM 60 Mangrove

50 Pastureland 40 30 17 Agroforestry 20

10

5 Abra Kalinga-Apayao Ilocos Sur Mt. Prov. SOIL CARBON Ifugao La Union Nueva Vizcaya

Sub-Prov. of Aurora SEQUESTRATION IN

Pampanga

Rizal

Cavite Laguna Catanduanes AGRICULTURAL Batangas

Isabela Camarines Sur Marinduque ECOSYSTEMS IN

Eastern Zamboanga Samar Zamboanga del CityLeyte SOUTHERN Norte Guimaras PHILIPPINES

Agusan del Sur Zamboanga Bukidnon de Norte Zamboanga Zamboanga del Sur Davao del Norte North Cotabato Davao Compostela del Sur ZamboangaCity Valley

South Cotabato Sibugay General. Santos City Agricultural ecosystems

Adtuyon Soils Faraon Soils • developed from weathered • derived from weathering of rocks that originated from coralline limestone, includes volcanic lava (lahars) chiefly soils with rolling topography composed of anditdesites and to hilly area basalts • pH of 7.18 • pH of 5315.31 • external ddirainage good • external drainage is good to under forest but becomes excessive excessive in open fields. • internal drainage is fair to • internal drainage is fair. good Tillage and cropping systems

• TILLAGE SYSTEMS • CROPPING SYSTEMS – No‐tillage – Corn cropping – Conservation tillage – Corn‐legume rotation – Conventional tillage – Vegetables – Root crops – Cover crops – Pasture/grassland – Banana – Fruit crops Effects of tillage systems on carbon of soils.

TILLAGE SOC, % SEQUESTERED SYSTEMS CO2 EQUIVALENT Faraon

No Tillage 2.01 256

Conservation 2.04 261 Tillage Conventional 1.75 227 Tillage Adtuyon

No Tillage 3143.14 393

Conservation 3.10 382 Tillage Conventional 3.09 383 Tillage Adtuyon vs. Faraon Effect of cropping systems on carbon of soils CROPPING SOC, % Sequestered CO2 Equivalent SYSTEMS (Mg/ha) Adtuyon Faraon Adtuyon Faraon

Annual cropping systems Corn 3.0. 1.88 352 241 Corn‐Legume 3.12 1.90 368 244 Vegetables 3.0 1.86 371 249 Rootcrops 2.98 1.85 361 243 Covercrop and forage cropping systems Covercrop 3.29 2.59 394 328 Pastures 3.26 2.28 398 326 Perennial cropping system Banana 3.27 2.58 389 325 FiFruitcrops 3133.13 1851.85 387 321 Adtuyon vs. Faraon Soil types and soil organic carbon 11 55 0606 107107 0000 0000 0000 1111 1 11 1 10 100 10 9696 9898 90 8989 8989 8787 80

70 6868 6666 6666 6666 C/ha 60 ggC/ha

MMMM 50

40

30

20

10

5 Corn Corn‐legume Vegetables Rootcrops Covercrop Banana Fruitcrops Adtuyon soils Faraon soils SUMMARY OF FINDINGS

1. Soil capacityyy to sequester carbon is dependent on soil type, soil ph, tillage system, and type of vegetation 2. Adtuyon soils sequstered more carbon than faraon due to its acidity tha t led t o l ess mi crobi al d ecompositi on 3. No tillage has highest carbon sequestration due mainly to no or no disturbance of soil structure 4. Tillage favors decomposition so less sequesterd carbon. 5. High bulk density of soil can be an indicator for high carbon sequestration Isabela Abra Kalinga-Apayao

Ilocos Sur Mt. Prov.

Province Ifugao La Union ASSESSMENT AND Nueva Vizcaya

Sub-Prov. of Aurora VALUATION OF Pampanga

Rizal

Cavite Laguna Catanduanes Batangas GHG MITIGATION Isabela Camarines Sur Marinduque IN LOWLAND RICE

Eastern Samar Leyte AGROECOSYSTEMS Guimaras

Agusan del Sur Zamboanga Bukidnon de Norte Zamboanga del Sur Davao del Norte North Cotabato Davao Compostela City Valley

South Cotabato General. Santos City Aggyroecosystem

• Provide updated information on the current GHGs emitted from rice cropping in lowland rice agroecosystems in Isabela as affected by different farm management practices and the amounts and economic values of GHG reduction of changing to a more climate‐ friendly farm management practices.

• Climate‐friendly farm management practices in lowland rice agroecosystems include those that have less emission of GHGs by avoiding anaerobic ddiiecomposition such as reddiucing the amounts and duration of irrigation, use of low methane emitting variety and rice straw composting. Farm management practices that add to GHG emission Climate‐friendly farm management practices Valuation: Lowland rice field and GHG

Values of CH4 emission reduction based on 2009 World Bank Carbon Price.

FARMING PRACTICE ANNUAL REDUCTIONCH4 VALUE * EMISSION tons CH4 CH4 % tons CO2e CO2e US$/yr P Million/yr Million/yr tons/yr

EXISTING PRACTICE 5,882.93 0 0 - -

MID-SEASON DRAINAGE 3,059.12 2,823.81 48.00 59,300.01 711,600.12 34.16 COMPOSTING 2,126.49 3,756.44 63.85 78,885.24 946,622.88 45.44 DRAINAGE + COMPOSTING 1,105.77 4,777.16 81.20 100,320.36 1,203,844.32 57.78

* WB PRICE = US$ 12/ton CO2e; P48/US$ SUMMARY OF FINDINGS 1. Mid-season drainage rather than continuous flooding will have 2,823.81 tons/year or 48% methane reduction in 7,789.34 ha service area of 30 selected

IAs in NIA-MRIIS District 2 with tradable CO2 equivalent of P34.16 million/year. 2. Application of rice straws composted aerobically rather than incorporated in flooded rice fields will have 3,756.44 tons/year or 64% methane reduction service area with a tradable CO2 equivalent of PhP45.44 million/year. 3. Simultaneous mid-season drainage and application of aerobic rice straw compost rather than existing farming practices (continuous flooding and rice straw incorporation in flooded fields) will have 4,777.16 tons/year or 81% methane reduction in the with tradable CO2 equivalent of PhP57.78 million/year. 4. Incremental benefits of shifting from existing farming practices (continuous flooding and rice straw incorporation) to climate-friendly farming practices (mid- season drainage and rice straw compost application) will be PhP138.95 million /year. SUGGESTIONS AND RECOMMENDATIONS

1. Development of cost-effective methodological tools and techniques in analyzing and determining soil organic carbon. This will allow quantification of carbon stocks and sequestration rates of carbon in the various ecosystems. For instance, data aggregation from a plot scale to national scale is a big barrier to overcome in carbon stock assessment. 2. Conduct of valuation studies for carbon trading purposes. Determining the actual value of SOC will bring appreciation at its importance to policymakers. 3. Promoting activities that will enhance the potentials of various ecosystems to serve as carbon sinks rather than sources. While soil carbon storage plays a crucial role in GHG mitigation, strategies to reduce carbon emission must be carried out with full understanding that there should bebalance between environmental benefits and need for food and fiber THANK YOU! Greenhouse Gases from Rice field Factors affecting GHG emission: • Land preparation • Seed pepaatopreparation • Rice varieties • Fertilizer application • Water management • Harvesting and fallow period • Rice straw management: Methane emission in a paddy rice ffldield burning and incorporated (Macandog & IRRI, 2007).