LADA Group Sri Lanka Natural Resources Management Centre Department - PowerPoint PPT Presentation

LADA Group Sri Lanka Natural Resources Management Centre Department of Agriculture Sri Lanka

 Lies in the between longitudes 79.5° - 81.8°E latitudes 5.9° - 9.8° N  Land Area 64,453.6 Km 2  Inland Water 1,156.2 Km 2  Maximum length 435 Km maximum width 225 Km  Extensive faulting and erosion over time have produced a wide range of topographic features

CLIMATE  Annual rainfall varies between 900 mm to over 5500 millimeters  Average Rainfall Dry zone → < 1,750 mm Intermediate zone → 1,750 -2,500 mm Wet zone → > 2,500 mm  Very high spatial variability of rainfall  46 Agro-ecological regions

Agro – ecological map of Sri Lanka

Soils of Sri Lanka Nine out of the ten major soil orders based on the USDA soil taxonomic system are distributed through out the country in a mosaic pattern (Panabokke, 1978)

Series level soil map of Sri Lanka soil series level spatial distribution in wet, intermediate and dry zone respectively

Land degradation processes in Sri Lanka 1. Soil erosion: loss of surface soil by water and wind. The productivity of 50 % of land in the agricultural sector is significantly affected due to soil erosion 2. Fertility decline: Net decrease in available nutrients and organic matter in the soil. The productivity of 30 % of land in the agricultural sector is significantly affected due to declining soil fertility. 3. Dystrification: Lowering of soil pH by increasing acidic compounds in soil. The productivity of agricultural lands particularly cultivated with tea, potato and vegetable in the up country wet zone are significantly affected due to acceleration of the dystrification process.

Land degradation processes in Sri Lanka. 4. Sealing and crusting: Clogging of pores in soil surface with fine soil material and development of a thin impermeable layer. It has been very common in lands exploited for seasonal agriculture in the Alfisols region in Sri Lanka. 5. Compaction: Deterioration of soil structure and formation of a dense layer by trampling or frequent use of machinery. It has been very common in rice lands on Alfisols where shallow farm implements such as rotary tillers are frequently used for land preparation. In this situation, a compacted soil horizon has been developed over the plow pan in rice lands causing a reduction in the effective depth of Ap horizon. 6. Salinization/alkalization: Net increase in salt content/sodium content of soil leading to significant decline in crop productivity. The productivity of low lands particularly in the low country dry zone are affected due to acceleration of salinization/alkalization processes

Land degradation processes in Sri Lanka.. 7. Water logging: Net increase in soil voids filled with water and it causes a significant decline in crop productivity. This situation is created temporally or permanently in soil due to increasing up of ground water table or lowering down of water infiltration as a result of human activities. It has been very common in lowland. Fortunately, as rice is grown well under waterlogged conditions, such lands are productively used in agriculture in Sri Lanka. 8. Subsidence: Lowering of soil surface particularly in organic soil. It has been reported from lands filled for non agricultural purposes in the Histosol region of Sri Lanka. 9. Aridification: A net decrease in average soil moisture content due to human activities. It has been reported from uplands particularly in the dry zone where greater fraction of precipitation goes as runoff. Therefore, it causes a decline in soil profile storage. 10. Pollution: Addition of materials to soil which causes toxic effects in soil. It has been reported in areas where industrial and urban waste is disposed over the land.

1.Assess Land Degradation at national and sub-national levels 2.Identify the Intensity and Trends of Land Degradation 3.Identify the priority areas / high risk areas 4.Identify the areas where the degradation has been slowed or reversed through conducive policies and actions 5.Build national and regional assessment capacities 6.Building a national / regional database of degradation status in aid of monitoring status / trends

 Development of Administration unit  Development of LUS maps  Combining LUS and ADMIN  Preparation of QM software for data processing  Collection of degradation related data  Entering data in LADA-QM  Degradation map development

Data Description Source of data 1 Landuse data Extracted from digital map layers of Survey department land use, water and built-up area of Sri Lanka from 1:50000 scale topographic map sheets 2 Admin boundary Admin boundaries for province, Digital Admin map map District, DSD and GN division has available at NRMC been used for LADA QM mapping unit was used development 3 Forest and wildlife The digital map of forest and Department of reserve reservation areas of has been used Forest 4 Elevation and Slope Slope map was developed using GIS 30m data analysis with 30m Digital Elevation downloaded from Model ASTGTM website

Data Description Source of data 5 Paddy area map Paddy land map updated by Natural Resources Forecasting project of NRMC for Management Ampara, Polonnaruwa and Batticaloa Centre, DOA. has been used 6 Climate data Rainfall and other climate data Met database, NRMC 7 Agro-ecological map Digital map has been Used for LUS Natural Resources boundary adjustments Management Centre, DOA. 8 Expert knowledge Expert knowledge and local Data gathered on land degradation experiences were included in the through guided LADA-QM approach discussions held in national workshops and informal small group meetings.

Data Description Source of data 9 Degradation related Information on prominent Information was information degradation types and affected extracted from localities were also used during available literature assessment 10 Erosion hazard Erosion hazard map of central Natural Resources maps highlands covering central and uva Management province was also used as a guide Centre, DOA. map for assess accuracy levels of LADA maps

 9 Provinces

 9 Provinces • 25 Districts

 District Codes

 9 Provinces  25 Districts  331 DS Divisions

 9 Provinces  25 Districts  331 DS Divisions  14,022 GN Divisions

 Central Province  Wide range of land use types  Wide range of land degradation levels  Hilly area  Wide range of climatic zones  Feeding area for most of the rivers and streams  Most sensitive area

Implementation area of the Soil Conservation Act Extraordinary Gazette No 1550 / 9 : 2008 May 22 Legend Low Moderate High Very high Soil conservation boundary Extraordinary Gazette No 1550 / 9 : 2008 May District boundary 22 Divisional secretariat boundary

 Central Province

 Central Province 36 DS Divisions

 9 Provinces  Admin ID  25 Districts [Dis_ID] [DSD_ID]  331 DS  Admin Code Divisions [Dis_Code]-[DSD Name]  Central Province 36 DS Divisions

 Admin ID

[Dis_ID] [DSD_ID]  Admin Code [Dis_Code]-[DSD Name]

 Developed by merging 92 map sheets (1;50,000)  49 classes  Corrections  Different names for same class  Edge matching  35 landuse classes

 35 Landuse classes in topo maps  Areas under forest & wildlife reserves  Re-classified in to 18 classes

11 Forest – Protected 12 Forest - Unmanaged 13 Woody Perennial - Protected 14 Vegetated Area – Protected 15 Sparsely Vegetated Area – Unmanaged 16 Grasslands – Protected 17 Grasslands - Unmanaged 18 Bare Area – Protected 19 Bare Area – Unmanaged 21 Perennial Agriculture - Coconut 22 Perennial Agriculture - Rubber 23 Perennial Agriculture - Tea 24 Woody Perennial Crops 25 Crop Lands 26 Paddy 31 Urban 32 Rock 41 Wetland - Protected 42 Wetland - Unmanaged 43 Open Water – Protected 44 Open Water

Combined Admin unit & LUS Map [ADMINCODE] & [0] & [LUSCODE]

CODE Degradation Type Bc Reduction in Vegetation Cover Bh Loss of Habitats Bl Loss of Soil life Cn Fertility Decline Et Loss of top soil Wg Gully Erosion Wt Surface Erosion

 Almost whole of the Central Province is suffering from land degradation  No or less degraded percentages were observed in areas with thick forest cover

 Human induced factors  Direct Drivers & Pressures  Unsystematic use of lands for continuous annual cropping  Haphazard / unplanned development activities  Inappropriate land reclamation  Mining & other industries  Unscientific solid waste management particularly in urban areas  Unsystematic landuses

 Human induced factors  Indirect Drivers & Pressures  Population pressure  Poverty  Inadequate and / or inappropriate policies and management  Lack of Land ownership  Land fragmentation