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Triple rice in a year: Is it feasible for low salinity areas of the

coastal zone of Bangladesh?

N. K. Saha, M. K. Mondal, E. Humphreys, M. H. Rashid, P. C. Paul, S. P. Ritu

Rationale

● Fresh water all the year round in much of Barisal● Current cropping patterns:

○ Fallow/Aus-T.Aman-Fallow/Keshari ○ 0-3 2-3.5 0-1 t/ha

● Possible technology to fit 3 rice crops in a year ● 50% cultivable land medium high (SRDI 2010)

● HYV rice ● River water for Boro, river water & rainfall for Aus

drainage to Aman crop.

Hypotheses of the study

● 3 high yielding rice crops per year IS possible in coastal zone where ○ fresh water available throughout the year○ ability to drain excess water

M J J A S O N D J F M A M

Boro (140-145 d) T. Aman (130-140 d)

Aus (100-105 d)

Objectives

To evaluate combination of planting dates and aman varieties for triple rice system● Feasibility● System yield● Irrigation water requirement for boro

Basic site information

● PSTU farm, Patuakhali● Clay loam● Lowland

Drain & Water source ~100 m

Treatments: ➢ E1-3: aus sowing dates/establishment method➢ V1-4: aman varieties➢ D1-5:boro sowing dates

Experimental design

● E1= Sown 10 April, transplanted 1 May● E2= Sown on 25 April, transplanted 15 May● E3= Sown Direct (wet) seeded 1 May

Variety: OM1490 (100 days)

Aus establishment treatments (E)

RULE: Transplanting date 10 d after harvest of each aus treatment

E1 and E2: ● V1 BRRI dhan49 (duration 135 d)● V2 BRRI dhan52 (duration 145 d, submergent tolerant)E3:● V3 BRRI dhan33 (duration 118 d)● V4 BRRI dhan53 (duration 125 d)

Aman variety treatments (V)

RULES: ● First transplanting date NOT less than 10 d after aman

harvest, & NOT before 15 November● Second transplanting date 15 d after first

● D1= 15 November ● D2= 20 November ● D3= 30 November ● D4= 05 December ● D5= 15 December

Boro sowing date treatments (D)

Treatment CombinationsAus Aman Boro CSE1 =1 May V1= BRRI dhan49 D1= 15 November 1

D2 = 30 November 2V2 =BRRI dhan52 D1= 15 November 3

D2 = 30 November 4E2=15 May V1 =BRRI dhan49 D1= 30 November 5

D2= 15 December 6V2 =BRRI dhan52 D1=30 November 7

D2=15 December 8E3=1 May V1 =BRRI dhan33 D1= 20 November 9

D2= 05 December 10V2= BRRI dhan53 D1=20 November 11

D2= o5 December 12

Crop management information

● Crop establishment: Transplanting (all crops): 21 day-old seedlings

20 cm x 20 cm Direct seeded aus (Dsaus): 20 cm row spacing

● Fertilizers:

Season N (kg/ha)

P2O5(kg/ha)

K2O(kg/ha)

CaSO4(kg/ha)

ZnSO4(kg/ha)

Aus 100 60 40 60 10

Aman 100 60 40 60 10

Boro 120 60 40 60 10

DS.aus 10-15 DAE, 30-35 DAE, 45-50 DAE(5-7DBPI) and 60-65 DAET.Aus

Final land preparation, 25 DAT, 5-7 DBPI and at headingT.Aman

Boro

BRRI, 2012

Irrigation: ● T.Aus and DSaus – irrigated as needed from canal● Boro– Fully irrigated from canal (pumping)

Drainage:Excess water during aus & aman– at low tide

Weed, pest and disease management • Good control of pests and diseases (BRRI, 2012 recs)(except brown spot in aman 2013 and boro 2012-13 first 2 sowings)• plastic barrier to keep rats out• netting to keep birds out

Bird nets

Plastic barrier

Crop Monitoring

● Phenology dates:● PI, FL, PM

● Biomass: fortnightly● Yield and yield components:

● Panicles/m2 ● Florets/panicle● Floret fertility● 1000 grain wt. ● Grain & straw yield

● The amount of water/plot: ○ pump discharge rate (R), duration of irrigation (T), and plot

area (A). ○ Formula: (R X T)/A

Irrigation monitoring

T. Aman 2012

Field duration of aman crop

Field water depth during aman 2012

Effect of sowing date and variety on grain yield of aman

Field duration of aus crop

Effect of sowing date on aus yield

Aus crop

Effect of sowing date on boro duration

Daily mean temperature during boro 2012-13 and 2013-14

Effect of sowing date on yield of boro

Boro crop

Total system grain yield

Duration of the cropping pattern in the field during 2012-13 and 2013-14

Conclusion & Recommendation

● It is feasible to fit 3 rice crop in a year● 13.4 to 17.2 t/ha/yr about 3 x farmers’ harvest● Average 10-12 day turn around period● Need for model simulation to evaluate performance

over range of weather conditions● Will pests & diseases become a problem in triple rice

systems – need for ecologically friendly management systems

Thank you

Irrigation water requirement during boro 2012-13 to 2013-14

Irrigation water productivity(kg/ha-mm) of BRRI dhan28 during boro 2012-13 to 2013-14