This document discusses optimizing irrigation requirements for boro rice through timely sowing and use of short duration varieties in West Bengal, India. Key points: - Early sowing of boro nurseries in the first week of November and transplanting in December requires 16 cm less irrigation for land preparation and 5-15 fewer irrigations than normal late sowing practices. - Short duration varieties that mature in 110-130 days require 4-5 fewer irrigations compared to longer duration varieties. - Early sowing allows the crop to benefit from residual soil moisture and avoids increased evaporation and temperatures in late winter/spring that increase irrigation needs.

1. Op#mising
irriga#on
requirement
of
boro
rice
through
#mely
sowing
and
short
dura#on
varie#es
ICAR-­‐Central
Soil
Salinity
Research
Ins#tute
(CSSRI)
RRS,
Canning
Town,
India
Revitalizing
the
Ganges
Coastal
Zone
21
-­‐23
October,
2014,
Dhaka,
Bangladesh
Sukanta
K.
Sarangi,
D.
Burman,
S.
Mandal,
B.
Maji,
Elizabeth
Humphreys,
To
Phuc
Tuong,
B.
K.
Bandyopadhyay
and
D.
K.
Sharma

2. Agro-­‐climaCc
zones
of
WB
N
E

3. Holding
Size
in
Coastal
Zone
(%)
District
Marginal
(<
1ha)
Small
(1-­‐2
ha)
Semi-­‐medium
(2-­‐<4
ha)
Medium
(4-­‐<10
ha)
Large
(>10
ha)
North
24
Parganas
88
9
2
0.1
<0.1
South
24
Parganas
86
12
1
0.1
Neg
East
Midnapur
93
6
0.7
<0.1
Neg
Howrah
94
5
0.4
<0.1
Neg
Mean
(coastal
zone)
90
8
1
<0.1
Neg
Mean
(non-­‐coastal
zone)
78
16
5
0.5
<0.1
Neg
=
negligible
Marginal
farmers
dominate
the
coastal
zone
of
West
Bengal

4. Site
Net
Cropped
Area
Boro
area
Boro
area
%
of
NCA
Coastal
N24
P
62
11
18
Coastal
S24
P
232
25
11
North
24
P
257
95
37
South
24
P
374
70
19
Source:
District
Agriculture
Plan
North
24
Parganas
and
South
24
Parganas,
2010-­‐11
Boro
Area
(000’
ha)
in
the
target
sites

5. Rice
Produc#vity
(t
ha-­‐1):
Boro
vs
Aman
Block/District/
State
Salt-­‐affected
area*
Boro
Aman
Gosaba
100
2.1
1.6
Sandeshkhali
100
2.8
2.0
South
24
Parganas
92
3.0
2.2
North
24
Parganas
58
3.3
2.8
West
Bengal
14
4.1
3.6
*
%
of
cul#vable
area

6. •
Rice
is
essen#al
for
food
security
•
Irriga#on
source
is
confined
aquifer
•
Source
is
finite,
scarcity
of
water
•
U#liza#on
is
likely
to
increase
Need
&
Scope
for
Op#mising
Irriga#on
Requirement
for
Boro
Scope
Possibility
Low
Medium
High
Method
of
Irriga#on
√
Establishment
method
√
Alterna#ve
source
√
Op#mising
sowing
date
√
Short
dura#on
variety
√

7. Month
Season
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Aman
Boro
Present
Rice
Cropping
Calendar
Month
Season
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Aman
Boro
With
introduc#on
of
short
dura#on
varie#es
(<10
days
)
and
advancing
boro
nursery
sowing
(15-­‐20
days)
>150
days
135
-­‐140days
Suggested
Rice
Cropping
Calendar

8. Experimental
Design
and
Treatments
Nursery
Seeding
Date
D1:
Early
seeding
(First
week
of
November)
D2:
Normal
seeding/Farmers’
pracCce
(Last
week
of
Nov)
Varie#es/Lines
(Replicated
thrice
in
RBD)
BRRI
dhan
47
BRRI
dhan
53
BRRI
dhan
55
BINA
dhan
8
CSR
34
CSR
22
IR
10206-­‐29-­‐2-­‐1-­‐1
CSRC
(S)
50-­‐2-­‐1-­‐1-­‐4-­‐B

9. Irriga#on
required
for
Land
Soaking
and
Puddling
• Early land preparation in December required
16 cm less irrigation water than in January
0
5
10
15
20
25
30
35
40
Early
Land
PreparaCon
(First
week
of
December)
Late
Land
PreparaCon
(First
week
of
January)
Irriga#on
water
(cm)
21.6
cm
37.7cm

10. Soil
is
weler
at
#me
of
land
prepara#on
for
early
sowing,
reducing
irriga#on
requirement
Deposi#on
of
salts
and
crack
forma#on
in
January
Residual
soil
moisture
in
December

11. Number
of
irriga#on
required
for
Boro
from
transplan#ng
to
maturity
•
Early
sown
boro
required
5
irriga#ons
less
than
late
sown
•
Shorter
dura#on
varie#es
required
4-­‐5
fewer
irriga#ons
than
longer
0
5
10
15
20
25
Number
of
irriga#ons
Early
Sowing
(1st
Week
of
Nov.)
Late
Sowing
(Last
Week
of
Nov.)

12. 0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0
5
10
15
20
25
30
35
40
45
Nov/13
Dec/13
Jan/14
Feb/14
Mar/14
Apr/14
May/14
EvaporaCon
Max.
Air
temp.
Min.
Air
temp.
Weather
becomes
drier
with
progress
of
Boro
season
Air
temperature
(0C)
Evapora#on
(mm
day-­‐1)
Early
sowing
Normal
sowing
Early
Land
prepara#on
Normal
Land
prepara#on
Flowering
in
Early
Sowing
Flowering
in
Normal
Sowing
Early
Harvest
Normal
Harvest

13. 0
20
40
60
80
100
120
140
160
180
Total
irriga#on
water
(cm)
Early
sowing
Late
sowing
Total
Depth
of
Irriga#on
Required
for
Boro
(mean
of
2
years)
•
BRRI
dhan
55
required
significantly
less
water
than
all
others
with
early
sowing
•
Early
sown
crop
required
20
cm
lesser
water
than
late
sowing

14. 105
110
115
120
125
130
135
140
145
Maturity
Dura#on
(Days)
Early
sowing
Late
sowing
Maturity
dura#on
of
boro
rice
(2
year
means)
•
Dura#on
reduced
due
to
late
sowing
•
Early
to
mature
was
BRRI
dhan
55

15. Effect
of
Sowing
Date
and
Variety
on
Spikelet
Fer#lity
and
Boro
Rice
Yield
•
Spikelet
fer#lity
was
highest
in
BINA
dhan
8
(81-­‐89%)
•
7%
reduc#on
in
spikelet
fer#lity
due
to
late
sowing
•
Highest
grain
yield
in
BINA
dhan
8,
CSR
22,BRRI
dhan
47
&
IR
10206
•
Grain
yield
reduced
by
11%
due
to
late
sowing
0
10
20
30
40
50
60
70
80
90
100
Spikelet
fer#lity
%
Early
sowing
Late
sowing
0
1
2
3
4
5
6
7
Early
Sowing
Late
sowing
Grain
yield
(t
ha-­‐1)

16. Variety
Early
seeding
Normal
seeding
BRRI
dhan
47
47
37
BINA
dhan
8
46
40
IR
10206-­‐29-­‐2-­‐1-­‐1
45
37
CSRC(S)
50-­‐2-­‐1-­‐1-­‐4-­‐B
35
25
Means
42
34
LSD
(P=0.05)
1.5
1.3
Irriga#on
Water
Produc#vity
(kg
ha-­‐1
cm-­‐1)
•
Early
sown
boro
has
higher
WP

17. 0
1
2
3
4
5
6
7
20
30
40
50
Grain
Yield
(t
ha-­‐1)
Water
Produc#vity
(kg
ha-­‐1
cm-­‐1)
y
=
-­‐12.97+
9.74x
r
=
0.92
0
20
40
60
80
100
120
140
160
180
20
30
40
50
Irriga#on
water
(cm)
Water
Produc#vity
(kg
ha-­‐1
cm-­‐1)
y
=
202.72
-­‐
1.63
x
r
=
-­‐0.87
Water
Produc#vity
posi#vely
correlated
with
grain
yield
and
nega#vely
correlated
with
total
irriga#on
water
input

18. CONCLUSION
•
Poten#al
to
increase
yield
of
boro
in
coastal
zone
of
West
Bengal
•
Shorter
dura#on
variety
and
early
crop
establishment
reduced
irriga#on
water
input
and
increased
water
produc#vity
•
Efforts
needed
to
ensure
#mely
availability
of
quality
seeds
of
improved
varie#es
to
farmers

19. ACKNOWLEDGEMENTS
•
G2
project
on
“Produc#ve,
profitable,
and
resilient
agriculture
and
aquaculture
systems”,
a
project
of
the
CGIAR
Challenge
Program
on
Water
and
Food
(CPWF)
•
Financial
support
by
the
Interna#onal
Rice
Research
Ins#tute
(IRRI)
•
Facili#es
to
conduct
the
experiments
by
the
Central
Soil
Salinity
Research
Ins#tute
(CSSRI)

20. THANK
YOU
Let
us
produce
more
crop
per
drop