Silvino Q. Tejada, Rodelio B. Carating*, Juliet Manguera, and Irvin Samalca Bureau of Soils and Water Management

 Introduction  Agricultural Geography  The Nature of Land Degradation  Primary Causes of Land Degradation  Impacts of Land Degradation  Assessment of Land Degradation - National level assessment - Project level assessment  The Philippine National Action Plan

 As per study of the Global Assessment of Land Degradation and Improvement showed that the total degraded lands in the Philippines is estimated at 132,275 square kilometers affecting about 33,064,629 Filipinos.  The World Bank in 1989 estimated annual value of on-site fertility losses due to unsustainable upland agriculture in the Philippines to be around US$ 100 M, equal to 1 percent of Philippine GDP per year.

 The agricultural economy of the Philippines is reflective of a complex mix of several cropping systems, numerous land control systems, localized labor systems, and differentiated trade, exchange, and consumption systems (Gultiano, et. al.,2003)  Rice is the traditional crop and central to the rural agricultural economy  Corn has grown to be an important crop and gained dominance where rainfall is sporadic and the soils and slopes are conducive to corn than to rice.

(1) Accelerated water erosion is the most common type of land degradation in the Philippines. (2) Nutrient mining and soil fertility decline. Since the Green Revolution of the mid 1960’s, the Philippine agriculture has become conventional by 1980s.  characterized by need to use nitrogen fertilizers only.  – requires higher phosphorus fertilizer inputs in addition to nitrogen.  – there is need to include higher levels of potassium and micronutrients like zinc in addition to nitrogen and phosphorus fertilizers.

 By 2005, there has been a major shift in government policies when Pres. Gloria Macapagal -Arroyo issued E.O. 481 to promote and develop organic agriculture as a farming scheme. a. This is a significant milestone in Philippine agricultural production policy as we refocus on our natural resources than on external resources. b. The national government recognizes that farming methods which neglect the ecology of the soil, crops and nature damage the farming environment and inimical to our national interest.

(3) Problem soils – the heavy cracking clays are about 766,388 hectares (2.6% of total land area); acid soils total about 12,067,994 hectares (roughly 40%) ; and salt-affected soils (mostly in coastal areas) are about 400,000 hectares (1.3%); poor drainage soils are about 90,880 hectares (0.3%) and coarse textured soils are about 482,849 hectares (1.6%).

 Intensive logging over decades  Unsustainable agricultural practices in the sloping uplands

 Loss of soil fertility and consequent decline in agricultural productivity  Loss of water and decline in water quality

 National level scale assessment BSWM has developed the Agricultural Resources Information System (ARIS) which integrated the Soil Information System (SIS) and the Land Resources Information System (LARIS). Added to the ARIS is the Water Resouces Information System which basically caters to the small-scale irrigation projects of BSWM ARIS consists of data, query, and model sub- systems.

 At the query sub- system, we retrieved the erosion map (with emphasis on moderate and severe erosion areas and overlay with the slope map and the land use map to come with Land Degradation Assessment: The Hot Spots

Erosion dataSlope dataLand-use data ARIS spatial database Query sub-system Land degradation hot spots Land degradation bright spots E0 E1E2 E3 3-8% 8-18% 18-30% >30% agric grass forest others Map overlay

Region Area (Ha) ARMM 104, CAR 597, CARAGA 311, REGION I (ILOCOS REGION) 363, REGION II (CAGAYAN VALLEY) 538, REGION III (CENTRAL LUZON) 221, REGION IV-A (CALABARZON) 238, REGION IV-B (MIMAROPA) 350, REGION IX (ZAMBOANGA PENINSULA) 167, REGION V (BICOL REGION) 160, REGION VI (WESTERN VISAYAS) 383, REGION VII (CENTRAL VISAYAS) 446, REGION VIII (EASTERN VISAYAS) 362, REGION X (NORTHERN MINDANAO) 409, REGION XI (DAVAO REGION) 417, REGION XII (SOCCSKSARGEN) 295, Total 5,367,046.98

 Focusing this time on none to slight erosion areas and overlaying on slope map and land use map (except for open lands and cultivated areas), we came up with Land Degradation Assessment: Bright Spots.

RegionArea (Ha) ARMM15, CAR242, CARAGA91, REGION I (ILOCOS REGION)55, REGION II (CAGAYAN VALLEY)135, REGION III (CENTRAL LUZON)131, REGION IV-A (CALABARZON)168, REGION IV-B (MIMAROPA)110, REGION IX (ZAMBOANGA PENINSULA)64, REGION V (BICOL REGION)47, REGION VI (WESTERN VISAYAS)78, REGION VII (CENTRAL VISAYAS)17, REGION VIII (EASTERN VISAYAS)145, REGION X (NORTHERN MINDANAO)107, REGION XI (DAVAO REGION)91, REGION XII (SOCCSKSARGEN)91, Total1,594,171.97

 The data here is sum of more than 30 years of BSWM land resources assessment  Currently, validations are conducted at project level. (e.g. SAFDZ-CLUP Integration, BSWM-JICA Project, Bohol ACIAR Project, Spatial geodatabase for corn monitoring, etc.)  We just updated in 2008 our GIS and Remote Sensing facilities and acquired 36 scenes of SPOT5 (234 scenes needed to cover the whole country).  Prior to this, our country-wide satellite imageries are MOS 1 – MESSR,

 SAFDZ- CLUP Integration (about 37 of 1,607 municipalities in the Philippines; 3 are on- going). Sample erosion map from Iligan City SAFDZ-CLUP Integration

 Thematic maps – soils*, land management units, slope*, erosion*, elevation, land use*, flooding  Decision maps – land limitation*, crop suitability maps (depends on crop grown and proposed by the LGU)  SAFDZ Map *Spatial inputs for land degradation assessments

Example on Bohol Inabanga Watershed Project with ACIAR-Australia  GIS-Based Land and Water Resources Evaluation  Digital map outputs – administrative map, watershed, soils, soil series, soil depth, land use, dominant land cover, slope, erosion, forestry suitability, crop suitability (oil palm, grassland,, land degradation hot spot  Studies on satellite imageries - Bohol island digital map elevation model, Normalized Difference Vegetation Index (NDVI)

 Landsat7 ETM+false color composite subsets August 30, 2000 March 29, 2002 December 26, 2002

 NDVI for the multi-temporal Landsat7 ETM+ subset August 30, 2000 March 29, 2002 December 26, 2002

 Classified Landsat7 ETM+ images March 2002August 2000 December 2002 Figure 12. Trends in land cover/land use based on the classified Landsat 7 ETM+ images.

 Identification of Land Degradation Hot Spots using ArcView 3.2 and ILWIS 3.2 Figure 19. The upstream sub-watersheds. limestone areas shallow soils highly erodible soils Figure 20. Combined soil limiting attributes.

Figure 21. Soil limiting attributes vs. intensive agricultural use. areas with intensive agricultural use Figure 22. Result of the intersection of soil limiting attributes and intensive agricultural use.

Figure 23. Intensive agricultural use with soil limiting attributes vs. agricultural areas within the forest reservation. Figure 24. Result of the intersection between intensive agricultural use with soil limiting attributes and agricultural areas in forest reservation.

Figure 25. Resulting map layer in Figure 23 vs. sloping areas with >30% inclination. Figure 26. The so-called “hotspots”.

ELEVATION (masl) Figure 33. Digital elevation model (DEM) of Bohol Islands.

Overall development framework:  Sustainable agriculture  Forestry and rural development (with focus on water provision and technology based on community initiatives and participatory planning

Thematic Programs:  Sustainable agriculture and marginal uplands development program  Integrated ecosystems management Program Components:  Land and water technology development  Local governance and community initiatives  Database development and harmonization  Information, education, and communication  Enabling policy development

Expected OutputPerformance Indicator 1. Contribute to poverty alleviation through improved farm income Upland dwellers increase farm income by 30-40% 2. Rehabilitate degraded agricultural lands 200,000 hectares degraded lands rehabilitated 3. Construction of small water retention structures in marginal communities 100,000 units of small farm reservoirs, farm ponds, gully dams through co- sharing with local gov’t units 4. Establishment of participatory learning centers 15,000 farmers and gov’t technicians trained on rehab of degraded lands 5. Database on status of soil productivity decline, drought, and land degradation Info system linked with sub-regional (Southeast Asia) database