Run-off Water Harvesters andAgro-wells for Supplementary    Irrigation of Rain-fed         Sugarcane(A Preliminary Investi...
Commercial Sugarcane-     growing areas of Sri Lanka– Pelwatte - Sugar, Syrup and Ethanol– Sevanagala – Sugar, Syrup and E...
Extents under two water      regimes (ha)Irrigated – Sevanagala (1832ha)            Hingurana(5163ha)            KantaleRa...
Study area• LocationSevanagala Sugarcane Project• Latitude (within)60.26’36” - 60.20’44”• Longitude (within)              ...
Agro-ecological parameters – Sevanagala sugar                        Project• Situated in DL1 AEZ• Annual rainfall  – 1324...
Rainfall Pattern• Annual total rain fall (2010) - 1431.4mm• Rainy seasons - October to December (Maha)                  - ...
Irrigation in Sevanagala• Furrow irrigation – all the commercial cane-growing  areas•   Sprinkler irrigation – only in see...
Cane Yields in irrigated and rain-           fed sectors                               90                               80...
• The supplementary irrigation in the rain-  fed area is critically limited by scarcity of  water  – Potential water sourc...
Available water sources  in Sevanagala                                         An agro well at SevanagalaRun off in wet se...
Different water harvestingtechniques                                                   Cement tanks                       ...
Objective of the study• To investigate the possibility of run-off  water harvesting and using agro-wells for  supplementar...
Methodology• Study period: from 2009 to 2010• Three farmer fields in rain-fed area Land surveying in a farmer field       ...
Placement of run off water          harvester• constructed the run off water harvesting  structures at the low-lying areas...
Water harvesting structures were   constructed in the farmer fields (Procedure proposed by         HDRA (International Dev...
Data Collected• Volume of the water harvester        – Practical approach (actual water volume) –by pumping/ water        ...
Results & Discussion
Maximum possible capacity of        water harvester• The water harvesting structure can store  125 -150 m3 of water• Furth...
1 21 0  8  6  4  2      2   4   6   8   1 0   1 2   1 4   1 6   1 8   2 0   2 2    2 4                                    ...
Re-filling behavior                      Rainfall occurs (21mm/hr or more)                      during dry spell creates s...
Gound Water availability                                                                                                  ...
Conclusions• 150m3 of run-off water can easily be stored in the  proposed water collectors in Sevanagala rain-fed  sugarca...
Suggestions• Run-off water harvesting in Sevanagala  rain-fed sugarcane fields is not sufficient  to practice conventional...
Further study• Easy handling and low-cost overhead  irrigation system is being constructed with  locally available materia...
Acknowledgements•   Dr H.K Sunil – Former Director, Sugarcane Research Institute•   Mr. D.D Nanayakkara - Former Plantatio...
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Run-off Water Harvesters and Agro-wells for Supplementary Irrigation of Rain-fed Sugarcane (A Preliminary Investigation)

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L.M.J.R Wijayawardhana, K.H.D Abeyrathna, W.R.G Witharama
& A.P Keerthipala
Sugarcane Research Institute of Sri Lanka, Uda Walawe
International Forestry and Environment Symposium 2011 Annual Symposium organized by Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Nugegoda, Sri Lanka http://fesympo.sjp.ac.lk/

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Run-off Water Harvesters and Agro-wells for Supplementary Irrigation of Rain-fed Sugarcane (A Preliminary Investigation)

  1. 1. Run-off Water Harvesters andAgro-wells for Supplementary Irrigation of Rain-fed Sugarcane(A Preliminary Investigation)L.M.J.R Wijayawardhana, K.H.D Abeyrathna, W.R.G Witharama & A.P Keerthipala Sugarcane Research Institute of Sri Lanka, Uda Walawe
  2. 2. Commercial Sugarcane- growing areas of Sri Lanka– Pelwatte - Sugar, Syrup and Ethanol– Sevanagala – Sugar, Syrup and Ethanol– Hingurana – Re opened (2009)– Kantale – to be re opened/ no production– Badulla – Jaggery / cottage-level– Kilinochchi – Pilot project started in 2010 /Jaggery
  3. 3. Extents under two water regimes (ha)Irrigated – Sevanagala (1832ha) Hingurana(5163ha) KantaleRain-fed – Pelwatte (6490ha) Sevanagala (2387ha)
  4. 4. Study area• LocationSevanagala Sugarcane Project• Latitude (within)60.26’36” - 60.20’44”• Longitude (within) Rain-fed sector800.51’21” - 800.57’45”• SoilReddish brown earths• TerrainUndulating Irrigated sector• Soil bulk density1.2 – 1.65 g/cm
  5. 5. Agro-ecological parameters – Sevanagala sugar Project• Situated in DL1 AEZ• Annual rainfall – 1324.4 mm ±282.4 (1984-2010)• Annual pan evaporation – 1590.8 mm ±198.7 (1984-2010)
  6. 6. Rainfall Pattern• Annual total rain fall (2010) - 1431.4mm• Rainy seasons - October to December (Maha) - March to May (Yala)• Dry spells and durations – June to September (major) Sevanagala – January to February (minor) 450 400 Actual rainfall Rain fall (mm) 350 (mm) 300 Dependable (0.75) 250 rainfall 200 150 100 50 0 ec er O er ry il r A y p t st r Fe ary ch ne ay N obe be l pr u b b Ju ua Ju ar M em ug em em nu A br ct M Ja ov Se D Month 2010 Rain Fall - Sevanagala
  7. 7. Irrigation in Sevanagala• Furrow irrigation – all the commercial cane-growing areas• Sprinkler irrigation – only in seed cane nurseries• Irrigation interval – 9 – 12 days• Crop water requirement – 1500mm/year• Rainfall supplies approximately 2/5 of this requirement• 12 days
  8. 8. Cane Yields in irrigated and rain- fed sectors 90 80 Irrigated Cane harvest (t/ha) 70 Rain fed 60 50 40 30 20 10 0 2004 2005 2006 2007 2008 2009 Year• Average yield in Irrigated sector is 21% higher than rain- fed sector• This low yield in rain-fed sector can be reduced by irrigation
  9. 9. • The supplementary irrigation in the rain- fed area is critically limited by scarcity of water – Potential water sources • Groundwater in confined aquifers • Groundwater in unconfined aquifers • Run off water harvesting
  10. 10. Available water sources in Sevanagala An agro well at SevanagalaRun off in wet season at Sevanagala Farmer showing water logged place in D2 area, Sevanagala
  11. 11. Different water harvestingtechniques Cement tanks Poly lined ponds -India Water harvesting ditchesSmall tanks /ponds/ Pathaha – GroundwaterSri Lanka recharging wells
  12. 12. Objective of the study• To investigate the possibility of run-off water harvesting and using agro-wells for supplementary irrigation in rain-fed sugarcane fields in Sevanagala sugar project
  13. 13. Methodology• Study period: from 2009 to 2010• Three farmer fields in rain-fed area Land surveying in a farmer field Runoff water at lower catena of a farmer field
  14. 14. Placement of run off water harvester• constructed the run off water harvesting structures at the low-lying areas of the farmer field which is often flooded during the rainy season (this area can’t be utilized for sugarcane cultivation due to ill draining) Water logging caused to poor cane growth
  15. 15. Water harvesting structures were constructed in the farmer fields (Procedure proposed by HDRA (International Development Program, HDRA, UK)• Man power and heavy machinery were used to construct water collector
  16. 16. Data Collected• Volume of the water harvester – Practical approach (actual water volume) –by pumping/ water flow meter – Mathematical approach• No. of days required to re-fill the water harvester after each irrigation• Flow rates of the drain• Monthly rainfall data – From SSIL Pump installation at farmer field
  17. 17. Results & Discussion
  18. 18. Maximum possible capacity of water harvester• The water harvesting structure can store 125 -150 m3 of water• Further increase of run off water harvester’s capacity is limited because it, • reduces productive cultivable area • shallow groundwater level limits the depth • causes severe drainage problem during wet season / easiness to repair & de-silting, etc. • high cost of machinery • Farmer’s attitudes
  19. 19. 1 21 0 8 6 4 2 2 4 6 8 1 0 1 2 1 4 1 6 1 8 2 0 2 2 2 4 Capacity - 125 to 150 m3 The capacity of constructed water harvester is enough to irrigate only 0.2 ha sugarcane field under the conventional furrow irrigation method
  20. 20. Re-filling behavior Rainfall occurs (21mm/hr or more) during dry spell creates surface run off in RBE soils (Shanmuganathan, 1992) and recharge the water collector up to full capacity In-flow rate (after 9 days to heavy rain in April, 2009) is 180 l/min During heavy drought, it was 8.2 – 11.4 L/min (July, 2009)
  21. 21. Gound Water availability Rain Fall (mm) 600 600Depth to the water table from earth surface (cm) SOW-3 500 500 SOW-2 400 SOW-1 400 300 300 200 Rain Fall (mm) 200 100 100 0 0 1 2 3 4 5 6 7 8 Jan-10 Oct-09 Sep-09 Dec-09 Feb-10 Nov-09 Aug-09 Agro well at Sevanagala Groundwater level fluctuations in study area (3 agro wells) (August, 2009) Agro-wells were heavily utilised for irrigation during the 2nd dry spell in 2009 Field observations revealed that, these wells were refilled approximately within a week after each irrigation
  22. 22. Conclusions• 150m3 of run-off water can easily be stored in the proposed water collectors in Sevanagala rain-fed sugarcane fields• Water stored in these run-off water harvesters in Sevanagala rain-fed farmer fields is not sufficient to practice conventional furrow irrigation.• Supplementary irrigation systems can be introduced to rain-fed sugarcane fields in Sevanagala sugar project, by incorporating both runoff water harvesters with agro-wells.
  23. 23. Suggestions• Run-off water harvesting in Sevanagala rain-fed sugarcane fields is not sufficient to practice conventional furrow irrigation. Hence, it would be best under Regulated Deficit Irrigation• Over-head irrigation which makes possible controlling irrigation depth, would be more practical method to practise regulated deficit irrigation.
  24. 24. Further study• Easy handling and low-cost overhead irrigation system is being constructed with locally available materials, and is powered by two-wheel tractors that are more common in the sugarcane farming community at Sevanagala.
  25. 25. Acknowledgements• Dr H.K Sunil – Former Director, Sugarcane Research Institute• Mr. D.D Nanayakkara - Former Plantation Manager, Sevanagala Sugar Industries Limited• Mr. N.A.H.K Athula Siridewa – Agriculture Superintendent (Plantation), Sevanagala Sugar Industries Limited• Mr. M.U.K.U Kumara - Agriculture Superintendent (Division 3), Sevanagala Sugar Industries Limited• Mr. Nevilson - Former Agriculture Superintendent (Division 2), Sevanagala Sugar Industries Limited

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