Identification of the critical factors ofIdentification of the critical factors of
System of Rice Intensification (SRI) forSystem of Rice Intensification (SRI) for
maximizing Boro rice yield in Bangladeshmaximizing Boro rice yield in Bangladesh
Presented byPresented by
Md. Abu Bakar Siddique SarkerMd. Abu Bakar Siddique Sarker
Principal Scientific Officer, Agronomy DivisionPrincipal Scientific Officer, Agronomy Division
Bangladesh Rice Research Institute (BRRI)Bangladesh Rice Research Institute (BRRI)
Gazipur, BangladeshGazipur, Bangladesh

Significance of this research workSignificance of this research work
• Rice is the staple food of Bangladeshi people.
• Rice is currently cultivated on 10.61 million hectares, withRice is currently cultivated on 10.61 million hectares, with
production of 34.4 million tons, and average yield of 4.73 t haproduction of 34.4 million tons, and average yield of 4.73 t ha -1-1
(BRRI, 2014).(BRRI, 2014).
• This yield is well below that of other rice-growing countriesThis yield is well below that of other rice-growing countries
such as China, Japan, Korea and Egypt, with yields of 6.8,such as China, Japan, Korea and Egypt, with yields of 6.8,
6.7, 7.5, and 10.10 t ha6.7, 7.5, and 10.10 t ha-1-1
, respectively (IRRI, 2015)., respectively (IRRI, 2015).
• By 2025, the total rice area will probably be reduced by 5% or
so, while the 21% additional more rice needed by then will
have to be produced from less land (Bhuiyan et al., 2002).
• Further, varietal gains in yield potential have been declining.
• Higher rice production will thus have to be achieved mostly
through improvements in agronomic management.

The System of Rice Intensification developed inThe System of Rice Intensification developed in
MadagascarMadagascar is a set of specific crop managementis a set of specific crop management
practices, some of them counter-intuitive, that arepractices, some of them counter-intuitive, that are
based on certain principles whose applicationbased on certain principles whose application
should be adapted to local conditionsshould be adapted to local conditions rather thanrather than
simply adopted as a set package.simply adopted as a set package.
–– SRI is thus more like aSRI is thus more like a menumenu than athan a reciperecipe forfor
raising rice productivity.raising rice productivity.
SRI has the potential to improve rice production
without or with less dependence on:
• New rice varieties,
• Agrochemical inputs – fertilizers and biocides, or
• Large amounts of irrigation water.
It can contribute to a healthier natural
environment, with better water quality and soil
health
WHAT IS SRI ?WHAT IS SRI ?

• The technique is now being studied and
evaluated in many South and Southeast Asian
countries by
– Scientists,
– Extension workers, and
– Rice growers.
• SRI is gaining acceptance and use in all of the
rice-growing countries of Asia, where 90% of the
world's rice is grown.
– Its methods are being promoted by governments
in China, India, Indonesia, Cambodia and Vietnam,
which together grow 2/3 of the world’s rice.
• Results from many countries of the world give
evidence of quite positive results from SRI
methods (http://sri.cals.cornell.edu ).
– The benefits of SRI management have been seen
to date in 55 countries in Asia, Africa and Latin
America.

• SRI methodology in Bangladesh has beenSRI methodology in Bangladesh has been
reported to have a high production potential inreported to have a high production potential in
thethe BoroBoro season in comparison with currentlyseason in comparison with currently
recommended practices, farmer practices, therecommended practices, farmer practices, the
seedling-throwing method, and use of a drumseedling-throwing method, and use of a drum
seeder in light-textured soils (Sarkerseeder in light-textured soils (Sarker et al.et al.
2007).2007).
• Some GOs and NGOs in Bangladesh haveSome GOs and NGOs in Bangladesh have
initiated SRI method on a limited scale ininitiated SRI method on a limited scale in
farmer’s fields, and these trials have showedfarmer’s fields, and these trials have showed
promising results.promising results.
• It is seen that SRI can be a low-input, low-costIt is seen that SRI can be a low-input, low-cost
and high-productivity technology for theand high-productivity technology for the
resource-poor farmers.resource-poor farmers.
• The new techniques of SRI are expected toThe new techniques of SRI are expected to
change traditional management practices bychange traditional management practices by

The basic elements of SRI are:The basic elements of SRI are:
1. Start by transplanting younger seedlings (< 15
d), quickly and carefully, only 1-2 cm deep into
soil that is muddy but not flooded;
2. Transplant the seedlings far apart, one per hill,Transplant the seedlings far apart, one per hill,
and in a square pattern to facilitate weeding,and in a square pattern to facilitate weeding,
reducing plant population mreducing plant population m-2-2
by 80-90%;by 80-90%;
3.3. Keep the soil well-drained, not always flooded,Keep the soil well-drained, not always flooded,
maintaining mostly aerobic soil conditions;maintaining mostly aerobic soil conditions;
4.4. Control weed growth with a mechanical weederControl weed growth with a mechanical weeder
that aerates the soil, using early and often; andthat aerates the soil, using early and often; and
5.5. Improve soil structure and functioning byImprove soil structure and functioning by
building up soil organic matter with compost orbuilding up soil organic matter with compost or
other OM.other OM.
These practices together promote larger, healthier andThese practices together promote larger, healthier and
longer-lived root systems and more abundant, diverselonger-lived root systems and more abundant, diverse
communities of beneficial soil organisms that providecommunities of beneficial soil organisms that provide
services and protection.services and protection.
THE CRITICAL FACTORS OF SRITHE CRITICAL FACTORS OF SRI

 Find out the bestFind out the best crop establishment timecrop establishment time andand seedlingseedling
ageage for effective tiller production and crop performancefor effective tiller production and crop performance
in thein the BoroBoro season with SRI techniques;season with SRI techniques;
 FFind out the bestind out the best water management practiceswater management practices for cropfor crop
performance with SRI techniques;performance with SRI techniques;
 Find out the bestFind out the best integrated use of manure and fertilizerintegrated use of manure and fertilizer
for crop performance with SRI techniques;for crop performance with SRI techniques;
 Find out the effect ofFind out the effect of soil-stirring practicessoil-stirring practices for best cropfor best crop
performance under SRI management;performance under SRI management;
 Investigate the effects ofInvestigate the effects of spacingspacing andand seedling-raisingseedling-raising
methodmethod for higher performance of Boro rice under SRI;for higher performance of Boro rice under SRI;
 Find out and recommend theFind out and recommend the best combinationbest combination of criticalof critical
factors for yield maximization offactors for yield maximization of BoroBoro crop undercrop under SRI.SRI.
The study was undertaken with following objectives:The study was undertaken with following objectives:

The research was carried out at the Bangladesh RiceThe research was carried out at the Bangladesh Rice
Research Institute research farm at Gazipur, whichResearch Institute research farm at Gazipur, which
is:is:
– Located between 23Located between 23°°
59'23'' N latitude and59'23'' N latitude and
9090°°
24'19'' E longitude24'19'' E longitude
– Mean elevation is 49 ft above sea levelMean elevation is 49 ft above sea level
– Agro-ecological region is Madhupur TractAgro-ecological region is Madhupur Tract
– Mean annual precipitation is 2039 mmMean annual precipitation is 2039 mm
– Mean annual temperature is 25.7Mean annual temperature is 25.7°°
C, with aC, with a
mean maximum temperature of 30.4mean maximum temperature of 30.4°°
C, and aC, and a
mean minimum temperature of 21.1mean minimum temperature of 21.1°°
CC
– Day length ranging from 10.7 to 13.7 hours.Day length ranging from 10.7 to 13.7 hours.
Location of the experimentsLocation of the experiments

• Ten experiments were conducted over four years’Ten experiments were conducted over four years’
time to fulfill the above objectives.time to fulfill the above objectives.
• Experiments 1, 2, 3 and 4 were conducted in theExperiments 1, 2, 3 and 4 were conducted in the
11stst
year (year (BoroBoro 2007-2008) and were repeated the2007-2008) and were repeated the
next year (next year (BoroBoro 2008-09) as experiments 5, 6, 72008-09) as experiments 5, 6, 7
and 8 for confirmation of the 1and 8 for confirmation of the 1stst
year results.year results.
• Based on evaluation of the 1Based on evaluation of the 1stst
and 2and 2ndnd
year results,year results,
experiment 9 was designed for the 3experiment 9 was designed for the 3rdrd
year (year (BoroBoro
2009-10) in which the best practice performances2009-10) in which the best practice performances
were further evaluated against each other.were further evaluated against each other.
• Then in the 4Then in the 4thth
year (2010-11), experiment 10 wasyear (2010-11), experiment 10 was
undertaken for a controlled comparison, testingundertaken for a controlled comparison, testing
the SRI practices that had shown themselves to bethe SRI practices that had shown themselves to be
the best in previous trials against the ricethe best in previous trials against the rice
production system currently being recommendedproduction system currently being recommended
forfor BoroBoro season by BRRI.season by BRRI.
Methodology followed

• Results of Experiments 1 and 5Results of Experiments 1 and 5 : Grain yield under SRI at early: Grain yield under SRI at early
transplantation (November 15) and late transplantation (aftertransplantation (November 15) and late transplantation (after
January 15) did not perform so well, whereas transplantingJanuary 15) did not perform so well, whereas transplanting
between November 30 to December 15 produced higher yield.between November 30 to December 15 produced higher yield.
• When germinated seed was transplanted, grain yield wasWhen germinated seed was transplanted, grain yield was
lower, while it was increased from us of 8-day and 12-day oldlower, while it was increased from us of 8-day and 12-day old
seedlings. No yield increase was seen with 16-day oldseedlings. No yield increase was seen with 16-day old
seedlings.seedlings.
Conclusion:Conclusion: Transplanting under SRI should be done betweenTransplanting under SRI should be done between
December 01 to December 15 and with 12-day old seedlings.December 01 to December 15 and with 12-day old seedlings.

Pictures of different stages of 1st experimentPictures of different stages of 1st experiment
Active tillering stageActive tillering stage Panicle-initiating stagePanicle-initiating stage
Grain-filling stageGrain-filling stage Ripening stageRipening stage

Factor A: Water managementFactor A: Water management Factor B: Soil stirringFactor B: Soil stirring
II11 = Conventional flooding= Conventional flooding SS11 = 1 stirring at 20 DAT= 1 stirring at 20 DAT
II22 = Shallow AWD irrigation at 3 days= Shallow AWD irrigation at 3 days SS22 = 2 stirrings at 20 and 35 DAT= 2 stirrings at 20 and 35 DAT
II33 = Shallow AWD irrigation at 5 days= Shallow AWD irrigation at 5 days SS33 = 3 stirrings at 20, 35 and 45 DAT= 3 stirrings at 20, 35 and 45 DAT
II44 = Shallow AWD irrigation at 7 days= Shallow AWD irrigation at 7 days SS44 = Weekly stirrings after 15 DAT= Weekly stirrings after 15 DAT
II55, I, I66 = Deeper irrigation when water table goes below 15 or 25 cm (measured by pipe)= Deeper irrigation when water table goes below 15 or 25 cm (measured by pipe)
Results of Experiments 2 and 6Results of Experiments 2 and 6 ::
Higher grain yield was achieved under Irrigation IHigher grain yield was achieved under Irrigation I 22 (water at 3-day(water at 3-day
intervals) compared to other tested water managementintervals) compared to other tested water management
practices. Similarly stirring Spractices. Similarly stirring S33 (three stirrings) gave(three stirrings) gave

Results of Experiments 3 and 7Results of Experiments 3 and 7 ::
Higher grain yield was obtained with fertilizer/manure managementHigher grain yield was obtained with fertilizer/manure management
treatments Ntreatments N66 and Nand N77 (100% rec. inorganic + 5 or 10 t ha(100% rec. inorganic + 5 or 10 t ha -1-1
manure).manure).
Stirring SStirring S22 (stirrings at(stirrings at 15, 30 and 45 DAT)15, 30 and 45 DAT) gave the best graingave the best grain
yield.yield.
To achieve maximum grain yield under SRI, fertilizer and manureTo achieve maximum grain yield under SRI, fertilizer and manure
management either Nmanagement either N66 or Nor N77 may used with Stirring Smay used with Stirring S22 management.management.

Results of Experiments 4 and 8: Higher grain yield
was observed in spacings S5
(30 x25 cm) and S6
(30x30 cm) together with seedling-raising methods M2
and M3
(10d seedlings raised in compost or normal-soil
nursery beds).

Pictures of different stages of experiments 4 and 8
Seedling-raising methodsSeedling-raising methods Maximum tillering stageMaximum tillering stage
Maturity stageMaturity stage

Experiment 9
On the basis of 1On the basis of 1stst
and 2and 2ndnd
year information, experiment 9 evaluated:year information, experiment 9 evaluated:
Factor A: Spacing (2 treatments)Factor A: Spacing (2 treatments)
SS11 = 25 x 15 cm= 25 x 15 cm
SS22 = 30 x 30 cm= 30 x 30 cm
Factor B: Water management methods (2 treatments)Factor B: Water management methods (2 treatments)
II11 = 5-7 cm depth of water was added to field, followed by further= 5-7 cm depth of water was added to field, followed by further
irrigation at 3 days after disappearance. This was continued fromirrigation at 3 days after disappearance. This was continued from
15 DAT to PI stage, then 5-7 cm standing water was kept up to15 DAT to PI stage, then 5-7 cm standing water was kept up to
hard dough stagehard dough stage
II22 = 2-3 cm depth of water was added to field during irrigation just for= 2-3 cm depth of water was added to field during irrigation just for
soaking the soil; then further irrigation was added at 3 days aftersoaking the soil; then further irrigation was added at 3 days after
disappearing. This was continued from 15 DAT to PI stage; thendisappearing. This was continued from 15 DAT to PI stage; then
5-7 cm standing water was kept up to hard dough stage5-7 cm standing water was kept up to hard dough stage
Factor C: Fertilizer and manure management (2 treatments)Factor C: Fertilizer and manure management (2 treatments)
NN11 = 100% of the recommended inorganic fertilizer= 100% of the recommended inorganic fertilizer
NN22 = 10 t/ha of manure + 100% of the recommended inorganic= 10 t/ha of manure + 100% of the recommended inorganic
fertilizerfertilizer
Factor D: Soil stirring (2 treatments)Factor D: Soil stirring (2 treatments)
M1 = No soil stirringM1 = No soil stirring
M2 = Stirring at 15 DAT, 30 DAT, and 45 DATM2 = Stirring at 15 DAT, 30 DAT, and 45 DAT

SpacingSpacing
(S)(S)
SeedlingSeedling
(M)(M)
IrrigationIrrigation
(I)(I)
Nutrients (N)Nutrients (N) MeanMean DifferenceDifference
NN11 NN22
SS11 MM11 II11 9.83 a9.83 a 8.57 b8.57 b 9.209.20 1.25 **1.25 **
SS11 MM11 II22 8.65 b8.65 b 7.65 c7.65 c 8.158.15 1.00 **1.00 **
SS11
MM22 II11 9.65 a9.65 a 8.62 b8.62 b 9.149.14 1.03**1.03**
SS11
MM22 II22 8.78 b8.78 b 7.29 c7.29 c 8.048.04 1.50**1.50**
SS22 MM11 II11 9.62 a9.62 a 8.38 b8.38 b 9.009.00 1.24**1.24**
SS22 MM11 II22 9.48 a9.48 a 8.86 b8.86 b 8.978.97 1.02**1.02**
SS22 MM22 II11 9.58 a9.58 a 8.66 b8.66 b 9.129.12 0.91**0.91**
SS22 MM22 II22 8.79 b8.79 b 7.16 c7.16 c 7.987.98 1.63**1.63**
Interaction effects of selected factors of SRI practice on the grain
yield (t ha-1
) of BRRI dhan29 in Boro season, 2009-10
** 1% significance
Conclusion:Conclusion: Highest yield performance was obtained byHighest yield performance was obtained by
combination ofcombination of S1 M1 N1 I1S1 M1 N1 I1 treatmentstreatments (9.83 t/ha)(9.83 t/ha) followed byfollowed by S1S1
M2 N1 I1M2 N1 I1 (9.65 t/ha),(9.65 t/ha), thenthen S2 M1 N1 I1S2 M1 N1 I1 (9.62 t/ha)(9.62 t/ha)

Results of 9Results of 9thth
experimentexperiment
The highest grain yield (9.83 t haThe highest grain yield (9.83 t ha-1-1
) was recorded when:) was recorded when:
 12-day-old seedlings raised in compost bed (M12-day-old seedlings raised in compost bed (M11 ))
werewere
 Transplanted with 30 × 25-cm spacing (STransplanted with 30 × 25-cm spacing (S11 ),),
 Maintaining 2-3 cm depth of irrigation from 15 DAT,Maintaining 2-3 cm depth of irrigation from 15 DAT,
followed by further irrigations at 3-day intervals afterfollowed by further irrigations at 3-day intervals after
disappearance during vegetative growth period (Idisappearance during vegetative growth period (I 11 ))
 Application of 10 t haApplication of 10 t ha-1-1
of manure + 100% of theof manure + 100% of the

Experiment 10Experiment 10
This experiment was based on the best performancesThis experiment was based on the best performances
for different SRI practices from the preceding 3 yearsfor different SRI practices from the preceding 3 years
of evaluation (experiments 1 through 9), beingof evaluation (experiments 1 through 9), being
designed as follows:designed as follows:
MAIN PLOTS : Stirring (M) 2 x Irrigation (I) 2 = 4 levelsMAIN PLOTS : Stirring (M) 2 x Irrigation (I) 2 = 4 levels
SUB-PLOTS: Spacing (S) 2 x Seedling Age (A) 2 = 4 levelsSUB-PLOTS: Spacing (S) 2 x Seedling Age (A) 2 = 4 levels
SUB-SUB-PLOTS: Manure & Fertilizer (N) = 2 levelsSUB-SUB-PLOTS: Manure & Fertilizer (N) = 2 levels
Treatments = 4 x 4 x 2 = 32 x 3 replications = 96 totalTreatments = 4 x 4 x 2 = 32 x 3 replications = 96 total

Results of Experiment 10Results of Experiment 10
** = significant at 1% level, * = significant at 5% level, ns = not significant
In a column under each A, means followed by a common letters are not significantly different at the 5% level by DMR
Sub-plotsSub-plots
(Spacing ×(Spacing ×
Seedling age)Seedling age)
Main plotsMain plots
(Irrigation ×(Irrigation ×
Stirring )Stirring )
Sub-sub plots (Nutrient management)Sub-sub plots (Nutrient management)
NN11 NN22 DifferencesDifferences
AA11 = M= M11 II11
5.27 c5.27 c
5.62 b5.62 b
6.04 ab6.04 ab
6.65 a6.65 a
6.00 b6.00 b
6.28 b6.28 b
6.82 a6.82 a
7.08 a7.08 a
5.54 c5.54 c
6.39 b6.39 b
6.25 bc6.25 bc
7.72 a7.72 a
5.87 c5.87 c
7.03 b7.03 b
5.85 b5.85 b
6.72 b6.72 b
6.74 b6.74 b
7.39 a7.39 a
6.57 c6.57 c
6.93 bc6.93 bc
7.65 ab7.65 ab
7.79 a7.79 a
6.26 c6.26 c
7.48 b7.48 b
7.83 b7.83 b
9.43 a9.43 a
6.62 c6.62 c
7.84 b7.84 b
-0.58 *-0.58 *
-0.81 *-0.81 *
-0.70 *-0.70 *
-0.74 *-0.74 *
-0.57 *-0.57 *
-0.65 *-0.65 *
-0. 83 *-0. 83 *
-0.71 *-0.71 *
-0.72 *-0.72 *
-1.08 **-1.08 **
-1.58 **-1.58 **
-1.71 **-1.71 **
-0. 75 *-0. 75 *
-0.81 *-0.81 *
BB11 = S= S11 AA11
BB22 = S= S11 AA22
BB33 = S= S22 AA11
BB44 = S= S22 AA22
MM11 II11
MM11 II11
MM11 II11
MM11 II11
AA22 = M= M11 II22
BB11 = S= S11 AA11
BB22 = S= S11 AA22
BB33 = S= S22 AA11
BB44 = S= S22 AA22
MM11 II22
MM11 II22
MM11 II22
MM11 II22
AA33 = M= M22 II11
BB11 = S= S11 AA11
BB22 = S= S11 AA22
BB33 = S= S22 AA11
BB44 = S= S22 AA22
MM22 II11
MM22 II11
MM22 II11
MM22 II11
AA44 = M= M22 II22
BB11 = S= S11 AA11
BB22 = S= S11 AA22
BB = S= S AA
MM22 II22
MM22 II22
MM II

Conclusions:Conclusions:
It was observed that wider spacing (SIt was observed that wider spacing (S 22 ), SRI), SRI
irrigation methods (Iirrigation methods (I22 ), younger seedling age), younger seedling age
(A(A22 ), three stirrings (M), three stirrings (M22 ), and 10 t ha), and 10 t ha-1-1
compost with recommended inorganiccompost with recommended inorganic
fertilizers (Nfertilizers (N22 ) -- as interacting treatments --) -- as interacting treatments --
produced higher grain yield than presentlyproduced higher grain yield than presently
recommended spacing (Srecommended spacing (S11 ), irrigation), irrigation
method (Imethod (I22 ), seedling are (A), seedling are (A11 ) and no stirring) and no stirring
(M(M11 ).).
The highest grain yield (10.17 t haThe highest grain yield (10.17 t ha-1-1
) was) was
obtained from the treatment Sobtained from the treatment S22 AA22 MM22 II22 NN22

Conclusions and Recommendations:
Based on the study, it may be concluded that
integration of the best-performing SRI cultural
factors may be recommended for
maximization of Boro rice yield for a long-
duration variety like BRRI Dhan29 in
Bangladesh. The following best-performing
SRI cultural factors are to be considered:
1.Transplanting should be done during the
period from 30 November to 15 December.
2.Younger seedlings of 12-days age,
preferably raised in compost bed, should be
used for transplanting.

Conclusions and Recommendations:
3.Transplanting may be done with wider spacing
of 30 cm × 25 cm than at present.
4.SRI irrigation management should be
followed.
5.Soil stirrings at 15, 30 and 45 DAT may
enhance the productivity of irrigated rice.
6.BRRI-recommended fertilizer applications are
not enough for maximizing grain yield with SRI
techniques.
Integrated use of fertilizer plus manure at 10 t
ha-1
using the recommended rate for inorganic
fertilizers would enhance rice crop productivity
in Boro season.

Future Research
However, further research should be conducted to
address the following important issues:
• Research shall be done with the selected SRI
cultural factors for medium- and short-duration
MVs and hybrid rice varieties in the Boro
season to assess how to further optimize grain
yield.
• Research on selected SRI cultural factors on
different problem soils, especially light-
textured soils and saline soil, may be
continued.
• Research on determining cost-effectiveness for

Acknowledgements
• Professor Dr. Najrul Islam
• Professor Dr. M. A. Samad
• BRRI Authority
• Department of Agronomy, BAU,
Mymenshing
• Agronomy Division, BRRI, Gazipur