An innovative water management approach for increasing land productivity in the polders
of the coastal zone of Bangladesh
Manoranjan Mondal, Elizabeth Humphreys, Sudhir Yadav – IRRI
S. V. Krishna Jagadish – KSU Zahirul Haque Khan, Asish Sutradhar – IWM
Plenary session : Natural Resource Management (NRM) 08 January 2018, Dhaka, Bangladesh
12-Jan-19 1
Coastal zone is rich with water resources, offers HUGE POTENTIAL for Bangladesh to make a quantum leap in meeting FUTURE FOOD SECURITY requirements and achieving SDG 1 & SDG 2 (No Poverty & Zero Hunger) 1.2 Mha lands in polders underutilized Improved appropriate agricultural
technologies
Dry Season Wet Season
Take home message
July
November August
Take home message
WATERLOGGING is the main constraint, not the SALINITY
September
DRAINAGE in aman season is the key intervention and the ENTRY POINT for cropping system INTENSIFICATION in CZ
May
Because of hydrology, INDIVIDUAL alone cannot successfully adopt improved agricultural technologies in the polders of the coastal zone
Hydrological unit COMMUNITY coordination
within a hydrological unit is necessary for wide-scale adoption of improved agricultural technologies
Take home message
• Coastal zone is the most climate vulnerable region of the Ganges delta
• Home to the poorest, most food insecure, vulnerable people
• GoB constructed 139 polders to protect 1.2 M-ha low lying coastal areas from tidal flood and saline water intrusion
• Productivity is very low, much less than most of Bangladesh – missed out of Green Revolution
Coastal zone and polders
Sluice gate/regulator Q ~ 6-26 m3/s
Coastal ecosystem & hydrology
Coastal ecosystem & hydrology
• Different hydrology and agro-environments
• Hydrology is governed by
• Water salinity o SC region: fresh water (2030) o SW region: saline + fresh
• Soil salinity o ~ 75% land low & medium saline o ~ 25% land highly saline o Salt-tolerant crops o Management practices
• High salinity is an OPPORTUNITY – Shrimp-(rice+fish) – Year-round aquaculture
Perceived challenge: Salinity
May 2012
KHULNA BARISAL
May 2030 CC(A1B) w 22 cm SLR
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Improved agro-technologies for high saline coastal zone
Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
Traditional Climate Risky (2-7 t/ha)
Existing cropping in polders (farmers’ practice)
Improved & climate-resilient agro-technologies for CZ
May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May
Tidal river water + rainfall Pump from polder canal
Medium saline REY: 7-10 t/ha/yr
Low saline REY: 15-21 t/ha/yr
High saline Rice: 3 t/ha Shrimp: ~300 kg/ha Fish: ~3 t/ha
Why productivity LOW?
HIGH
LOW
Despite huge efforts from GoB NGOs Development partners International orgs
Because of o Hydrology o Inappropriate o Hypothesis o Technology
dissemination model
How to overcome CHALLENGE ?
• Coordination between • Bangladesh Water Development Board (BWDB) and • Department of Agricultural Extension (DAE)
is needed for wide-scale and year-round adoption of improved production systems in the polders of the CZ
Sluice gate/ regulator managed by BWDB
Agriculture managed by DAE
How to overcome CHALLENGE ?
• Community Coordination and Synchronized Cropping based on Hydrological Unit are required for wide-scale adoption of improved production systems in CZ
Hydrological unit
• Water Management Organizations should be formed based on hydrological unit not by geographical area (village)
Why synchronized cropping & community involvement?
HYV rice harvested on 3 Nov 2016 in polder 30
The ENTRY point for cropping intensification is HYV rice in aman
HYV rice harvested on 20 Nov in polder 43/2F
Polder 30: Khulna
Polder 43/2F: Barguna
Sesame/mungbean on 30 Jan 2016
~3 weeks earlier than FP
Dibbling sunflower on 17 Dec 2015
(2 months earlier than FP)
Why synchronized cropping & community involvement? Community water management creates opportunities for early establishment safe harvest of rabi crops
May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
Low saline REY: 15-21 t/ha/yr
Traditional Climate Risky (2-7 t/ha/yr)
Improved and Climate Resilient
Medium saline REY: 7-10 t/ha/yr
Why synchronized cropping & community involvement?
18 12-Jan-19
Community water management and synchronized climate-resilient cropping is necessary for cropping intensification in CZ. If the improved production system is adopted to 50% of the 1.2
Mha polder area, ~ 5 MILLION TONS ADDITIONAL FOOD GRAINS can easily be produced per year (SDG 1 and SDG 2)
Concluding remarks: Food Security/SDG