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