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Decentralized surface water irrigation as a pathway for sustainable intensification in southern Bangladesh: on how much land can the drop be brought to the crop?

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Decentralized surface water irrigation as a pathway for sustainable intensification in southern Bangladesh: on how much land can the drop be brought to the crop?

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By Urs Schulthess, Timothy J. Krupnik, Zia Uddin Ahmed, Andy J. McDonald

Revitalizing the Ganges Coastal Zone Conference
21-23 October 2014, Dhaka, Bangladesh
http://waterandfood.org/ganges-conference/

By Urs Schulthess, Timothy J. Krupnik, Zia Uddin Ahmed, Andy J. McDonald

Revitalizing the Ganges Coastal Zone Conference
21-23 October 2014, Dhaka, Bangladesh
http://waterandfood.org/ganges-conference/

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Decentralized surface water irrigation as a pathway for sustainable intensification in southern Bangladesh: on how much land can the drop be brought to the crop?

  1. 1. Urs Schulthess ⏐Timothy J. Krupnik ⏐Zia Uddin Ahmed ⏐Andy J. McDonald Decentralized Surface Water Irrigation as a pathway for sustainable intensification in Southern Bangladesh: On how much land can the drop be brought to the crop?
  2. 2. A three part presentation: 1.  Surface water irrigation as a pathway to sustainable intensification (SI) in Southern Bangladesh 2.  Targeting decentralized surface water irrigation to boost double cropping 3.  Future research and conclusions
  3. 3. Part 1: Surface water irrigation as a pathway to sustainable intensification (SI) in Southern Bangladesh
  4. 4. Meandryseasongroundwatertabledepth(m)   The emerging irrigation bottleneck in intensive boro production zones Source: Qureshi, Ahmed, and Krupnik (2014)
  5. 5. The Master Plan For Agricultural Development In The South The Southern Delta of Bangladesh •  Low crop intensification and fallows •  3.44 million farm households, majority poor (MoA and FAO, 2012) •  Rice-based farming system •  Target for most international aid The Southern Delta Master Plan: A $7.2 billion donor investment request •  The south: Dense network of rivers and canals, poorly used for irrigation •  Emphasis on expanding surface water irrigation to alleviate irrigation bottlenecks in the North •  Key aim: sustainable intensification to boost productivity and alleviate poverty
  6. 6. Sustainable intensification (SI) in Southern Bangladesh In practice, SI has two major approaches: •  ‘Crop’ intensification: Boosting yield, while sparing resources and harnessing ecological services (e.g., yield focused) •  ‘Systems’ intensification: Moving from one to two crops, while sparing resources and harnessing ecological services (e.g., double cropping focused) •  Bangladesh: loosing agricultural land (-10% in the last decade) (Hassan et al. 2013) •  SI: ‘. . . producing more output from the same area of land while reducing the negative environmental impacts and … increasing contributions to natural capital and the flow of environmental services’ (Pretty et al. 2011)
  7. 7. Irrigation a must to scale up double cropping in Southern Bangladesh
  8. 8. How can dry season irrigation be encouraged? •  Large-scale, centralized irrigation schemes? Extremely costly and challenging to maintain: •  Ganges-Kabadak (1955) – most land in 72,000 ha already double cropped. Siltation, bank instability, etc. (Brammer, 2002) •  Barisal Irrigation Project (1980). Slated for 42,000 ha achieved < 20% (cf. Gumma et al., 2014). •  Unfavorable conditions for farmers to access and use state provided pumps (Brammer, 2002) •  Bangladesh’s historical irrigation boom: thousands of decentralized irrigation service providers serving 10–20 ha Supplies 90% of Bangladesh’s irrigation (Chowdhury, 2010) Could this work for Southern Bangladesh? •  Technological options exist to address energy and cost problems (Axial flow pumps, other pumps) •  Service provider networks and water users groups need to be established •  Problems remain with appropriate siting of small command schemes to encourage double cropping Krupnik et al. 2013
  9. 9. Part 2: Targeting decentralized surface water irrigation to boost double cropping
  10. 10. Forgoing the fallow and establishing rabi croppin •  Location and estimates of fallow land vary by year, method, and definition: •  800,000 ha (Rawson et al., 2011) •  634,000 ha (BADC 2010) •  136,000 ha (MoA and FAO, 2012) •  240,000 ha (BBS, 2011) •  No estimates are related to targeting fallows for surface water irrigation and intensification •  Analytical challenges: Fallow identification, soil and water salinity, water availability, timely land availability
  11. 11. Targeting ‘best-bet’ areas for intensifying cropping using surface water irrigation in S. Bangladesh A complex process using GIS and remote sensing (RS) Using publically available data •  Hydrozone à GIS •  Water ways à RS •  Duration of surface water à RS •  Water salinity à monitoring/GIS •  Soil salinity à survey/GIS (SRDI) •  Land type à Elevation •  Crop land à RS •  Land use intensity à RS
  12. 12. Study area: South Central and South West Bangladesh Area:  3.374    million  ha  
  13. 13. Dynamic river system feet km 4000 1 feet km 4000 1 feet km 4000 1 Apr  12,  2014  Nov  23,  2009  Feb  17,  2004  
  14. 14. Surface Water
  15. 15. Presence of surface water in January Feyisa,  G.L.,  Meilby,  H.,  Fensholt,  R.,  Simon,  R.,  Proud,  S.R.,  2014.  Automated  Water  ExtracKon  Index:  A  new     Technique  for  surface  water  mapping  using  Landsat  imagery.  Remote  Sensing  of  Environment  140,  23-­‐35.  
  16. 16. Presence of surface water in February
  17. 17. Presence of surface water in March
  18. 18. Surface water salinity in January Source  of  surface  water  salinity  data:  BWDB.  Data  from  2002–2012  were  used.  
  19. 19. Surface water salinity in February
  20. 20. Surface water salinity in March
  21. 21. Surface water salinity in April
  22. 22. Soil salinity Source:  SRDI,  2000.  Soil  Salinity  Bangladesh.  Soil  Resources  Development  InsKtute.,  Dhaka,  Bangladesh.  
  23. 23. Suitability Matrix based on surface water and soil salinity 0"#2 "2"#"4" >"4 "0"#2" Highly"suitability Medium"suitability Non"suitable "2"#"4" Medium"suitability Low"suitability Non"suitable >"4 Non"suitable Non"suitable Non"suitable Water&Salinity&[dS/m] Soil& Salinity& [dS/m]
  24. 24. Land suitability based on soil and surface water salinity
  25. 25. Landscape elevation (Kharif inundation class) Above  flood  level   Up  to  90  cm   90  –  180  cm   180  –  300  cm   >  300  cm   Normal  flooding  depth   Aer:  Brammer,  H.  2012.  The  physical  geography  of  Bangladesh.      
  26. 26. Reflectance of light from leaves as function of wavelength NDVI = NIR - Red NIR + Red Normalized  difference  vegetaKon  index  
  27. 27. 27 Ground Cover (GC) and Leaf Area Index (LAI) Ground Cover is the percentage of ground covered by green vegetation when seen from above. It is a good indicator of: Productivity Stresses Diseases GC  =  1  –  exp(-­‐k  *  LAI)  
  28. 28. Prediction of LAI with the Enhanced Vegetation Index (EVI) Guindin-­‐Garcia,  N.,  Gitelson,  A.A.,  Arkebauer,  T.J.,  Shanahan,  J.,  Weiss,  A.,  2012.  An  evaluaKon  of  MODIS  8-­‐and  16-­‐day  composite   products  for  monitoring  maize  green  leaf  area  index.  Agric.  For.  Meteorol.  161,  15-­‐25.    
  29. 29. Using EVI to assess rabi land use intensity 2013-14
  30. 30. Using EVI to assess rabi land use intensity 2013-14
  31. 31. Using EVI to assess rabi land use intensity 2013-14
  32. 32. Using EVI to assess rabi land use intensity 2013-14
  33. 33. Using EVI to assess rabi land use intensity
  34. 34. Using EVI to assess rabi land use intensity
  35. 35. Using EVI to assess rabi land use intensity
  36. 36. Resulting land use intensity, rabi 2013–14
  37. 37. Resulting land use intensity in Southern Bangladesh (ha) Cropping intensity 2011–12 2012–13 2013–14 Average Fallow land 271,078 218,806 230,824 240,236 Low-intensity 779,095 915,548 906,382 867,008 High-intensity 876,338 790,732 789,735 818,935 Total 1,926,179
  38. 38. Resulting land use intensity in Southern Bangladesh (ha) Cropping intensity 2011–12 2012–13 2013–14 Average Fallow land 271,078 218,806 230,824 240,236 Low-intensity 779,095 915,548 906,382 867,008 High-intensity 876,338 790,732 789,735 818,935 Total 1,926,179 Compared to previous estimates for fallow land: •  800,000 ha (Rawson et al., 2011) •  634,000 ha (BADC 2010) •  136,000 ha (MoA and FAO, 2012) •  240,000 ha (BBS, 2011) All methods based on survey sampling and up-scaled estimation, with exception of Rawson et al., who included low-intensity crop land.
  39. 39. Targeting surface water irrigation to fallow and low land use intensity land
  40. 40. Detailed view: Land use intensity
  41. 41. Detailed view: Targeting surface water irrigation on fallow and low land use intensity land – 400 m buffer
  42. 42. Addressable land (ha) within a 400 m buffer of detectable surface water bodies (late March) Land use Highly Medium Low Not Intensity Suitable Suitability Suitability Suitable Fallow 14,524 6,866 2,144 23,631 Low Intensity 86,451 17,262 6,640 22,302 High Intensity 66,639 6,524 999 7,419 Total 167,615 30,652 9,783 53,352 The key output of this work is a detailed spatial database indicating the precise location of high- and medium- suitability fallow and low intensity lands upon which surface water irrigation could provide the key to unlocking the South’s agricultural productivity. This data base will soon be online and made available for development organizations, researchers, and policy makers.
  43. 43. Caveats •  Our estimate is conservative: FINNMAPS indicate we detected just ~25% of rivers and canals in the irrigable zone •  Methods are needed to rapidly assess water volume •  Cooperation is key: Good water governance and canal rehabilitation will be crucial for sustainable intensification. •  Research is needed to fine- tune irrigation scheduling recommendations to increase WP
  44. 44. Part 3: Future research: IrMASaT project (Irrigation Management Advisory with Remote Sensing)
  45. 45. Main high potential target zone for surface water irrigation Objectives: •  Regional and sub-regional watershed and scales: “safe operating space in canal systems” •  Surface water irrigation scheduling optimized: Maize, wheat, boro, mungbean
  46. 46. Octocopter and satellite images to address the spatial variability
  47. 47. Thank you! Questions? u.schulthess@cgiar.org
  48. 48. Land suitable for technology targeting

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