From S E Research To Modeling Impacts

754 views

Published on

Published in: Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
754
On SlideShare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
11
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

From S E Research To Modeling Impacts

  1. 1. From Soil Erosion Research to Modeling Impacts of Interventions: The Case of Ethiopia By Gete Zeleke GMP UN expert group meeting on “ Sustainable land management and agricultural practices in Africa: Bridging the gap between research and farmers” April 16 – 17, 2009, University of Gothenburg, Sweden.
  2. 2. <ul><li>Part I: Overview of Land Degradation </li></ul>
  3. 3. <ul><li>Huge gulley erosion - This process is still common in most parts of Ethiopia (mainly in potential areas) </li></ul>
  4. 4. <ul><li>Precious top soil that used to support life of different forms is washed out of the landscape and land is abandoned for any meaningful agricultural activity </li></ul>
  5. 5. Gete, 2005 Common in the rainy season
  6. 8. Land Cover in Dembecha Area, Ethiopia, in 1957 and 1995 Gete Zeleke 2000
  7. 9. Biological degradation : The invisible threat <ul><li>All soils in the country (except pastoralist areas) suffer from soil nutrient mining: Open nutrient cycle! </li></ul><ul><ul><li>Use of cow dung and crop residue as a source of energy in the country is equivalent to 700,000 tons of grain/year </li></ul></ul><ul><ul><li>Deteriorates chemical and physical properties of the soil </li></ul></ul><ul><ul><ul><li>OM content </li></ul></ul></ul><ul><ul><ul><li>Soil moisture holding capacity </li></ul></ul></ul><ul><ul><ul><li>Infiltration capacity </li></ul></ul></ul><ul><ul><ul><li>Soil structure </li></ul></ul></ul>
  8. 10. <ul><li>Part II: Some of the major causes </li></ul>
  9. 11. 1. Poor Land Management
  10. 12. <ul><li>Free grazing </li></ul><ul><ul><li>Deteriorates soil physical properties </li></ul></ul><ul><ul><li>Destroy soil conservation measures </li></ul></ul><ul><ul><li>Remove crop residue from the soil </li></ul></ul><ul><ul><li>Detach soil particles </li></ul></ul><ul><li>Unbalanced carrying capacity resulted in overgrazing </li></ul>2. Poor Livestock Management
  11. 13. 3. Energy sources for HH domestic use Amare, 2008
  12. 14. <ul><li>4. High Population Pressure: it is contextual </li></ul><ul><ul><li>Limited capacity and access </li></ul></ul><ul><ul><li>High level of illiteracy – weak awareness </li></ul></ul><ul><ul><li>Dependant on subsistent farming – 85% </li></ul></ul><ul><ul><li>Push people to marginal areas </li></ul></ul>Slide from Zelalem, 2006 Hurni, 2007
  13. 15. 5. Lack of proper awareness on extent and impacts of LD & other EPs <ul><li>Very poor resource database and utilization </li></ul><ul><ul><li>Eg. Soil database </li></ul></ul><ul><li>Lack of or incomplete empirical evidences on extent and impacts of LD and other EPs </li></ul><ul><li>Poor way of communication – e.g.. tones of soil/ha/y, ha of forest/y, % siltation, climate change...etc ******* </li></ul><ul><li>No cost benefit analysis </li></ul>
  14. 16. <ul><li>Part III: Experiences on SLM </li></ul>
  15. 18. (4) Water tables and water supply (5) Biomass for livestock and bee keeping
  16. 21. February 2004 October 2005 19 May 2003 October 2005
  17. 22. <ul><li>Part IV: Mechanisms of capturing process to influence agricultural development positively </li></ul>
  18. 23. What is need to make informed decisions on Agri. deve? <ul><ul><li>Need to have resource database (at least soil, water, climate and genetic resources…) </li></ul></ul><ul><ul><li>Need to know rate and magnitude of soil erosion/runoff under different AEZ, soil types, land use systems, etc </li></ul></ul><ul><ul><li>Need to know what technology works, where, and under what condition </li></ul></ul><ul><ul><li>Need to know negative impacts of Soil erosion (land degradation) and positive impacts of applying improved land management practices </li></ul></ul>
  19. 24. What are Possible approaches? <ul><li>Approach 1: </li></ul><ul><li>Measuring soil erosion in all watersheds </li></ul><ul><li>Measuring effects of all land management practices in different parts (too expensive) </li></ul><ul><li>Approach 2: </li></ul><ul><li>Measure selective and representative watersheds </li></ul><ul><li>Measure selective and right combinations of LM practices (Achievable) </li></ul><ul><li>Approach 3: </li></ul><ul><li>Extrapolate the result to ungauged areas using a combination of GIS, biophysical and economic models </li></ul><ul><ul><ul><ul><ul><li> (Achievable) </li></ul></ul></ul></ul></ul>
  20. 25. Framework for Assessing Major LD Processes & Impacts (Approach 2) LD On-site Off-site Types of Impacts <ul><li>Siltation/sedimentation </li></ul><ul><li>Reservoirs/dams </li></ul><ul><li>Lakes </li></ul><ul><li>On farm lands </li></ul><ul><li>Soil loss due to Sheet & rill erosion by water </li></ul><ul><li>Loss of soil nutrients through DB, CRB & GR </li></ul>Processes captured <ul><li>water supply </li></ul><ul><li>irrigation water supply </li></ul><ul><li>Power generation </li></ul><ul><li>Biodiversity </li></ul><ul><li>Destruction of productive lands </li></ul><ul><li>Production loss </li></ul>Impacts quantified
  21. 26. What do we have on this? LD On-site Off-site <ul><li>water supply </li></ul><ul><li>irrigation water supply </li></ul><ul><li>Power generation </li></ul><ul><li>Biodiversity </li></ul><ul><li>Destruction of productive lands </li></ul>Very little We know – SCRP & others <ul><li>Production loss </li></ul><ul><li>Siltation/sedimentation </li></ul><ul><li>Reservoirs/dams </li></ul><ul><li>Lakes </li></ul><ul><li>On farm lands </li></ul><ul><li>Soil loss due to Sheet & rill erosion by water </li></ul><ul><li>Loss of soil nutrients through DB, CRB & GR </li></ul>Types of Impacts Processes captured Impacts quantified
  22. 27. Afdeyu
  23. 28. <ul><li>Two key processes to be captured: </li></ul><ul><li>Watershed status (hill slope Processes </li></ul><ul><li>Stream gauging </li></ul>
  24. 29. Database from SCRP <ul><li>Watershed level </li></ul><ul><ul><li>Catchment runoff - hydrographs </li></ul></ul><ul><ul><li>Sediment yield </li></ul></ul><ul><ul><li>Climate </li></ul></ul><ul><ul><li>Land use </li></ul></ul><ul><ul><li>Harvest </li></ul></ul><ul><ul><li>Soil depth </li></ul></ul><ul><ul><li>Socio-economic data </li></ul></ul><ul><li>Plot level </li></ul><ul><ul><li>Soil loss </li></ul></ul><ul><ul><li>Runoff </li></ul></ul><ul><ul><li>Yield </li></ul></ul><ul><ul><li>SWC measures impact/land use/design/type </li></ul></ul>With and without scenario
  25. 30. Framework for Assessing Impacts of LM Practices (Approach 2 cont..) LM On-site Off-site Types of Impacts <ul><li>Effect in reducing Siltation/sedimentation </li></ul><ul><li>Reservoirs/dams </li></ul><ul><li>Lakes </li></ul><ul><li>On farm lands </li></ul><ul><li>Effectiveness in reducing soil loss </li></ul><ul><li>Effect in improving soil fertility and depth </li></ul><ul><li>Effect on moisture conservation and soil water holding capacity </li></ul>Processes captured <ul><li>water supply </li></ul><ul><li>irrigation water supply </li></ul><ul><li>Power generation </li></ul><ul><li>Biodiversity </li></ul><ul><li>Protection of productive lands </li></ul><ul><li>Production gains </li></ul>Impacts quantified
  26. 31. What do we have? LM On-site Off-site <ul><li>water supply </li></ul><ul><li>irrigation water supply </li></ul><ul><li>Power generation </li></ul><ul><li>Biodiversity </li></ul><ul><li>Protection of productive lands </li></ul>No measured data We have some data (SCRP/HLI/EIAR but need to be organized) <ul><li>Production gains </li></ul><ul><li>Effect in reducing Siltation/sedimentation </li></ul><ul><li>Reservoirs/dams </li></ul><ul><li>Lakes </li></ul><ul><li>On farm lands </li></ul><ul><li>Effectiveness in reducing soil loss </li></ul><ul><li>Effect in improving soil fertility and depth </li></ul><ul><li>Effect on moisture conservation and soil water holding capacity </li></ul>Types of Impacts Processes captured Impacts quantified
  27. 32. What is missing or less addressed? <ul><li>Offsite processes and impacts of LD </li></ul><ul><li>Info on impacts of LM practices (only few) </li></ul><ul><li>Info on impacts of integrated land management practices </li></ul><ul><li>Socio-economic aspects of SLM and LD (need more work) </li></ul>
  28. 33. Approach 3: Methods of extrapolation <ul><li>Selection of appropriate models and tools </li></ul><ul><ul><li>Modeling </li></ul></ul><ul><ul><ul><li>Model </li></ul></ul></ul><ul><ul><ul><ul><li>Choice of appropriate model </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>USLE – On-site processes (soil loss) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>SWAT- Off-site process (siltation) </li></ul></ul></ul></ul></ul><ul><ul><ul><li>Gauged values to calibrate and validate model </li></ul></ul></ul><ul><ul><ul><ul><ul><li>SCRP watersheds </li></ul></ul></ul></ul></ul><ul><ul><li>GIS </li></ul></ul><ul><ul><ul><li>To identify recommendation domains </li></ul></ul></ul>
  29. 34. Methods of extrapolation cont… <ul><li>Steps to be followed </li></ul><ul><li>Characterize each station </li></ul><ul><ul><li>Biophysical parameters </li></ul></ul><ul><ul><li>Socio-economic parameters </li></ul></ul><ul><li>Reclassify country coverages of bio-physical and SE parameters </li></ul><ul><li>Identify recommendation domains </li></ul><ul><li>Test model on station </li></ul><ul><li>Calibrate and validate model using gauged station data </li></ul><ul><li>Apply model on recommendation domains </li></ul>
  30. 35. Processes of Identifying Recommendation Domains using GIS Environment (soil loss, Nutrient loss & SLM) <ul><li>- Altitude </li></ul><ul><li>- Rainfall </li></ul><ul><li>- LGP </li></ul><ul><li>- Slope </li></ul><ul><li>- Soil </li></ul><ul><li>Farming system </li></ul><ul><li>Land Use …etc </li></ul>Reclassify country coverage and develop layers for each parameter Recommend. Domains Develop Ranges of parameters Overlay (model) GIS Modelling
  31. 36. Examples of National coverage for key parameters
  32. 37. farming system Farming system: Ethiopia
  33. 38. extrapolation of station data based on similarity of environmental conditions
  34. 39. farming system Farming system: teff, wheat, maize & pulses Farming system – Similar to Anjeni
  35. 40. soils Soils – Similar to Anjeni
  36. 41. altitude Altitudinal belts – Similar to Anjeni
  37. 42. rainfall Annual rainfall – Similar to Anjeni
  38. 43. LGP – Similar to Anjeni
  39. 44. slope Slope – Similar to Anjeni
  40. 45. temperature Annual Meant Temp – Similar to Anjeni
  41. 46. GIS Modelling and Overlays: Areas that can be represented by Anjeni
  42. 47. Areas that can be represented by Anjeni- by woreda (range)
  43. 48. Areas that can be represented by Anjeni- by woreda ( best fit areas only )
  44. 49. Part V: Extrapolation A: Model application (Eg. USLE) to extrapolate on-site processes and impacts
  45. 50. LD On-site SLM <ul><li>Production loss </li></ul><ul><li>Soil loss due to Sheet & rill erosion by water </li></ul><ul><li>Loss of soil nutrients through DB, CRB & GR </li></ul>Types of Impacts Processes captured Impacts quantified <ul><li>Effectiveness in reducing soil loss </li></ul><ul><li>Effect in improving soil fertility and depth </li></ul><ul><li>Effect on moisture conservation and soil water holding capacity </li></ul><ul><li>Production gains </li></ul>
  46. 51. Phase I: Model validation at station level <ul><li>1. Quantifying Soil Loss: </li></ul><ul><li>Parameter generation </li></ul><ul><ul><li>R, K, S, L, C, P </li></ul></ul><ul><li>Model calibration </li></ul><ul><li>Parameter adjustment including methods of generation </li></ul><ul><li>Validate model </li></ul><ul><li>Recommend options for: </li></ul><ul><ul><li>Model response and interpretation requirements </li></ul></ul><ul><ul><li>procedures parameter generation </li></ul></ul><ul><ul><li>Options including tables, equations </li></ul></ul>
  47. 52. Parameter generation options <ul><li>Eg. K factor </li></ul><ul><li>1. </li></ul><ul><li>2. </li></ul><ul><li>3. </li></ul><ul><li>4. Or use table developed based on Ethiopian experience </li></ul>
  48. 53. 2. Quantifying Nutrient Loss <ul><li>We choose only three important ways of nutrient loss from the soil </li></ul><ul><ul><li>Burning of dung </li></ul></ul><ul><ul><li>Burning of crop residue </li></ul></ul><ul><ul><li>Removal of grain </li></ul></ul><ul><li>We consider three possibilities of nutrient addition to the soil </li></ul><ul><ul><li>Fixation </li></ul></ul><ul><ul><li>Weathering </li></ul></ul><ul><ul><li>Artificial fertilizer or manuring </li></ul></ul><ul><li>We only address two nutrients </li></ul><ul><ul><li>N </li></ul></ul><ul><ul><li>P </li></ul></ul><ul><li>Remark: the method can be used to include others </li></ul>
  49. 54. Procedures <ul><li>Determine nutrient content of dung, crop residue and major crops </li></ul><ul><li>Set conversion coefficient - % of energy consumption covered by dung and crop residue per person, per year </li></ul><ul><li>Convert this to dung and CR used </li></ul><ul><li>Convert this to N & P loss from dung and CR </li></ul>
  50. 55. Procedures cont… <ul><li>Estimate production of major crops for each zone and </li></ul><ul><li>Convert this into N & P loss </li></ul><ul><li>Calculate Nutrient addition by different means </li></ul><ul><li>Calculate net nutrient loss: </li></ul>
  51. 56. 3. Quantifying impacts of SLM practices <ul><li>1. Scenario 1. Only Physical SWC measures </li></ul><ul><ul><li>Use SCRP values </li></ul></ul><ul><ul><li>Adjust P factor </li></ul></ul><ul><li>2. Scenario 2. Physical SWC with SF/SMM </li></ul><ul><ul><li>Extrapolate from existing values or measure </li></ul></ul><ul><ul><li>Adjust P factor and may be C factor </li></ul></ul><ul><li>3. Scenario 3. All best LMP </li></ul><ul><ul><li>Extrapolate of measure </li></ul></ul><ul><ul><li>Adjust P factor and C factor </li></ul></ul><ul><li>4. Area closure and forestry – </li></ul><ul><ul><li>Extrapolate or measure </li></ul></ul><ul><ul><li>adjust P factor and C factor </li></ul></ul>
  52. 57. Phase II: Procedures of extrapolation to Recommendation Domains (Eg) Soil Loss (Map and Data) K- Map LS - Map C/P - Map R – Map Soil Map DEM Land Use Map Climate Overlay
  53. 58. B: Model application (Eg. SWAT) to extrapolate off-site processes and impacts
  54. 59. Off-site <ul><li>water supply </li></ul><ul><li>irrigation water supply </li></ul><ul><li>Power generation </li></ul><ul><li>Biodiversity loss </li></ul><ul><li>Destruction of productive lands </li></ul><ul><li>Improved: </li></ul><ul><li>water supply </li></ul><ul><li>irrigation water supply </li></ul><ul><li>Power generation </li></ul><ul><li>Biodiversity </li></ul><ul><li>Protection of productive lands </li></ul>LD SLM <ul><li>Siltation/sedimentation </li></ul><ul><li>Reservoirs/dams </li></ul><ul><li>Lakes </li></ul><ul><li>On farm lands </li></ul>Types of Impacts Processes captured Impacts quantified <ul><li>Effect in reducing Siltation/sedimentation </li></ul><ul><li>Reservoirs/dams </li></ul><ul><li>Lakes </li></ul><ul><li>On farm lands </li></ul>
  55. 60. 1. Quantifying siltation using SWAT <ul><li>SWAT is a dynamic watershed/basin model </li></ul><ul><li>Developed by USDA-ARS </li></ul><ul><li>It simulates: </li></ul><ul><ul><li>Crop growth </li></ul></ul><ul><ul><li>Hydrology </li></ul></ul><ul><ul><li>Soil erosion </li></ul></ul><ul><ul><li>Climate </li></ul></ul><ul><ul><li>Updates model parameters on a daily basis </li></ul></ul><ul><ul><li>It takes point sources as input </li></ul></ul><ul><ul><li>Impacts of land management practices </li></ul></ul><ul><ul><li>Point and non point pollutant </li></ul></ul><ul><li>Output: </li></ul><ul><ul><li>Sediment yield </li></ul></ul><ul><ul><li>Runoff </li></ul></ul><ul><ul><li>Nutrient and pollutant balance </li></ul></ul><ul><ul><li>Etc…… </li></ul></ul>
  56. 61. 1. Quantifying siltation using SWAT cont…. <ul><li>SWAT simulates at three levels </li></ul><ul><ul><li>HRU </li></ul></ul><ul><ul><ul><li>Homogenous units in terms of soil and land use </li></ul></ul></ul><ul><ul><li>Sub-basin (smaller watershed) </li></ul></ul><ul><ul><ul><li>Holds a number of HRU </li></ul></ul></ul><ul><ul><li>Basin (bigger watershed) </li></ul></ul><ul><ul><ul><li>Holds a number of sub-basins </li></ul></ul></ul><ul><li>Has GIS interface and the model can run through GIS </li></ul><ul><li>Has weather generator </li></ul>
  57. 62. HRUs Basin/Big watershed ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( ! ( drainage outlets drainage lines microbasins Sub- basin/sub-watershed
  58. 63. Procedures of using SAWT <ul><li>Validate model using SCRP station data </li></ul><ul><ul><li>Generate parameter </li></ul></ul><ul><ul><li>Conduct sensitivity analysis </li></ul></ul><ul><ul><li>Calibrate model </li></ul></ul><ul><ul><li>Adjust model parameters </li></ul></ul><ul><ul><li>Validate model </li></ul></ul><ul><li>Apply model on selected basins </li></ul><ul><ul><li>Prepare soil map and data </li></ul></ul><ul><ul><li>Prepare and use map and data </li></ul></ul><ul><ul><li>Prepare DEM </li></ul></ul><ul><ul><li>Map climate variables </li></ul></ul><ul><ul><li>Indicate point sources </li></ul></ul><ul><ul><li>Produce parameter – built model database </li></ul></ul><ul><ul><li>Run the model </li></ul></ul>
  59. 65. <ul><li>Build required resource database </li></ul><ul><li>Develop information on SLM scenarios </li></ul><ul><ul><li>Develop generic values based on some observation </li></ul></ul><ul><ul><li>If absolutely needed establish learning sites </li></ul></ul><ul><li>Build capacity </li></ul><ul><ul><li>On modelling </li></ul></ul><ul><ul><li>Parameterization </li></ul></ul><ul><li>Develop packages of recommendation </li></ul><ul><li>Develop feedback system among research, extension and policy makers </li></ul>Conclusion

×