improving drainage is crucial for cropping intensification in the poldered coastal zones of...
TRANSCRIPT
Improving drainage is crucial for cropping intensification in the polderred
coastal zones of Bangladesh
To Phuc Tuong, IRRIManoranjan Mondal, IRRI
Sanjida Parveen Ritu, BRRIAbul Kalam Sharifullah, BARD
Elizabeth Humphreys, IRRI
New Cropping Systems Development• With new varieties
– Short duration– Non photoperiod sensitive– Salt tolerance
• Cropping systems research • On farm water management
– On farm storage– Rainfall
• It is possible to have 2 or 3 crops per year which can avoid salinity and overcoming the water shortage in the dry season
Sesame-Aman-F = 3-4 t/haBoro-F-Aman = 11-13 t/haAus-Aman-Rabi = 12-42 t/ha
New Cropping Systems
Boro (140-145 d)1 May
20 July
1 Aug
25 Nov
5 Dec
5 Apr
T. Aman (130-140 d)
Aus (100-105 d)
M J J A S O N D J F M A M
River water EC5-15 dSm-1
River water EC 5-15 dSm-1
Rainfall ~1500 mm leaching down soil salinity
Aus-Aman-Boro Cropping System
New Cropping System
10 Apr 30 June
10 July
15 Nov 1 5AprRabi (130-140 d)
1 Dec T. Aman (130-140 d)
Aus (100-105 d)
A M J J A S O N D J F M A
Rainfall ~1500 mm leaching down soil salinityRiver water
EC 5-15 dSm-1
River water EC 5-15 dSm-1
Aus-Aman-Rabi Cropping System
Constrains to New Cropping Systems
A M J J A S O N D J F M A
T. Aman (130-140 d)
Aus (100-105 d) Rabi (130-140 d)
Deep flooding at the beginning of rainy season constrains the establishment of aman rice and adoption of modern high yielding varieties
Prolonged water log at the end of rainy season delay establishment of rabi crop
High Tide
Low Tide
LandLand Surface
Embankment
River Bed
Sluice gate1-2 m
How to Adopt New Cropping Systems?• To realize the new cropping system, it is crucial to
improve the drainage of the polders• Can drainage be improved? Yes
2-3 m
• Previous role: salinity and tidal surge prevention
• Now with new cropping systems, the polders have additional roles– Water supply and storage – Drainage
• New function: polder has to be treated as one “water management unit”
Re-assess the Role of Polders in New Cropping Systems
Water Management in Polder: Institutional Level
• Various institution “manage” different part of the polder
• BWDB: construction and maintenance of the embankment and sluices
• BADC: small irrigation system within polders
• LEGD: outside polders
• No one looks at polder is a comprehensive water management unit
Conclusion• With advances in germplasm, on-farm water
management, it is possible to have 2-3 crops/year despite of salinity and water shortage in the dry season
• We have to improve drainage• Polders have been built 40 years, ago, with
the new cropping systems…..polders have new roles
• New roles need new management, new institution set up
THANK YOU