Dr. Amod K. Thakur and Dr. Ashwani KumarWater Technology Centre for Eastern Region (ICAR)

Bhubaneswar, Orissa

SRI: Experience and EvaluationSRI: Experience and Evaluation

SRI results in 13 countries – 4,504 farmers - Average yields: 4.8-12.4 t/ha - Maximum yields: 7.1-15.3 t/ha

IWMI Research Report No. 75 (2004): - SRI doubled farmer’s net income per hectare

System of Rice Intensification responds to 21st century needs (N. Uphoff, Rice Today, July-Sept., 2004, p. 42)

SRI would permit small farmers to unlock currently untapped production potential of rice (Stoop et al., Agricultural Systems, 71:249-274 (2002)

As of October, 2004……………

Articles critical of SRI:

“Fantastic yields in SRI: fact or fallacy?” -- Sheehy et al. Field Crops Research, 88: 1-8 (2004): SRI has no inherent advantage over the conventional system, and extraordinarily high yields are likely to be the consequence of error

“SRI: Agronomic UFOs” -- and Cassman, Field Crops Research, 88: 9-10 (2004)

“Agronomic UFOs waste valuable scientific resources” -- Sinclair, Rice Today, July-Sept., 2004, p. 43

SRI: A debatable issue

There is a need for obtaining a more scientific understanding about SRI and research must focus on key processes involved Dobermann, Agricultural Systems 79: 261-281 (2004)

Research requires intensive investigations by those trained to understand the theoretical context by undertaking critical experiments Sinclair, Rice Today July-Sept., 2004, p. 43

Many institutions and individuals should join in helping to improve the understanding and spread of this innovation Stoop et al., (2002) and N. Uphoff (2004)

SRI: A researchable issue……

Objectives: Evaluate

Varietal performance

Impact of spacing

Effect of different water & N-level

Comparative performance

Results with SRI

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Varietal performance

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Khandagiri (short-duration)

Surendra (medium-duration)

CRHR-7 (hybrid)

Lalat (medium-duration – popular variety)

Savitri (long-duration)

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All the varieties performed better under SRI than conventional transplanted rice. SRI showed 36-49% higher yield than TP• Short-duration variety (Khandagiri): 36%, • Medium-duration and hybrid varieties: 42-45 %, • Long-duration: 49% more yield than TP

Tiller & panicle number per hill 2-3-times more than TP• However, tiller & panicle number per m2 lower in SRI

In SRI, panicle length, grains per spike, % grain ripening are major factors responsible for higher yield than TP

Salient Findings

Salient Findings

Effect of spacing

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Grain Yield (t/ha) under different spacings in SRI and TP

Khandagiri Surendra Savitri

Treatment Yield (t/ha)

% Change in yield

Yield (t/ha)

% Change in yield

Yield (t/ha) % Chang

e in yield

30cm x 30cm 2.97c -1.65 2.94d -33.48 3.86d -14.49

25cm x 25cm 3.42b 13.12 4.26bc -3.58 6.72a 49.00

20cm x 20cm 4.14a 36.93 6.27a 41.89 5.06b 34.37

15cm x 15cm 3.01c -0.39 4.21bc -4.71 4.40c -2.48

10cm x 10cm 2.88c -4.80 4.16c -5.84 4.23c -6.28

TP 3.02c - 4.42b - 4.51c -

In a column, means followed by same letter (s) do not differ significantly at 5% level by DMRT (n= 6)

As spacing decreases (from 30 cm x 30 cm to 10 cm x 10 cm), number of panicles per m2 increases but with shorter panicles

At wider spacing (more than 20 cm x 20 cm): Yield reduced due to lesser panicle number/m2

At closer spacing (less than 20 cm x 20 cm) : Yield reduced due to shorter panicles

Optimum spacing: For short -and medium-duration varieties, with SRI best is 20 cm x 20 cm; for long-duration varieties, 25 cm x 25 cm

At optimum spacing, the highest leaf area index (LAI) and greatest light interception by canopy were measuredW

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Salient FindingsSalient Findings

Effect of different water & N-levels

Grain yield (t/ha) under different irrigation and nitrogen levels under SRI and TP rice (var: Surendra)

CF: Continuous flooding (5-6 cm), DAD: days after disappearance of water

Nitrogen level

Grain yield (t/ha)

TP SRI

CF 3 DAD 5 DAD MEAN CF 3 DAD 5 DAD MEAN

N0 1.91 1.81 1.62 1.78 1.99 1.90 1.85 1.91

N60 3.56 3.46 3.13 3.38 3.89 4.19 4.17 4.08

N90 4.19 4.13 3.76 4.03 6.01 6.30 6.27 6.19

N120 4.20 4.13 3.59 3.97 5.78 6.05 5.98 5.93

MEAN 3.47 3.38 3.03 4.42 4.61 4.57LSD (0.05)

N- 1.42I- 0.31N X I- 0.26

N- 1.56I- 0.09N X I- 0.22

TP: CF and 3 DAD irrigation – No significant difference in yield5 DAD created water stress and reduced the yield level

SRI: 3 DAD and 5 DAD gave higher yield than CF5 DAD – No yield reduction

Optimum level of nitrogen in SRI was found to be 90 kg/ha.

Optimum water management practice in SRI is irrigation applied 5 days after disappearance of ponded water

In SRI, continuous flooding reduced yield by 5-7% yield; SRI is more drought-tolerant because of greater root growth

The highest water use efficiency (WUE) was found with SRI in 5 DAD treatment (i.e., 7.74 kg/ha-mm)

Water saving about 22-35% was attained with SRI mainly due to reduction in seepage and percolation losses, reduced nursery demand, and lesser need for land preparation

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Salient FindingsSalient Findings

Comparison

SRI vs. TP

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Management practices SRI

Recommended management

practices (RMP)

Seedling age at transplanting

10 days 21 days

Plant spacing and density

One seedling/hill 20 cm x 20 cm

Three seedlings/hill 20 cm x 10 cm

Weed control Three weedings by cono-weeder @10, 20 and 30 days after transplanting (DAT)

Hand weeding (manual) @ 10, 20 and 30 days after transplanting (DAT)

Water management

AWD applied 5 DAD during vegetative stage

Flooding with 5-6 cm depth of water during the vegetative stage

Nutrient management

Organic manure @ 5 t ha-1

Chemical fertilizers: 80 kg N ha-1, 40 kg P2O5 ha-1, 40 kg K2O ha-1

Entire amount of P was applied at the time of final land preparation. N and K were applied in three splits, i.e., 25% at 10 DAT, 50% at tillering stage (30 DAT), and 25% at panicle initiation stage (60 DAT)

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Ro

ot

Gro

wth

& a

ctiv

ity

SRI hills had better root development (deeper roots, more dry weight, root volume, and root length) and higher root activity (greater amount of root exudates and higher root exudation rate) than crop grown under RMP

Til

leri

ng

un

der

SR

I

The number of tillers and panicles per hill significantly increased (2.5 times -- up to 34 tillers) in SRI than TP, mainly because SRI plants were able to complete a greater number of phyllochrons (10th phyllochron in SRI, and 8th phyllochron in RMP) before the onset of reproductive stage of growth. However, the number of tillers/panicles per unit area was found to be less or not significantly different in SRI compared with TP

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Lea

f d

evel

op

men

tC

ano

py

stru

ctu

re &

li

gh

t In

terc

epti

on

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The number of leaves/hill, leaf area/hill, and area of flag leaves significantly higher in SRI than RMPThe size of individual leaf under SRI is more (14.72 cm2) than leaves under RMP (9.18 cm2)SRI plots had higher LAI than RMPMore SLW of leaves under SRI shows greater thickness of leaf.

SRI: Leaves are more erect with open-type canopy structureRMP: Closed-canopy structure

SRI: Erect leaves with spreading canopy intercept more light without shading RMP: In more closed canopy, lower leaves experience more shading

Ph

ysio

log

ical

O

bse

rvat

ion

sC

rop

Gro

wth

Rat

e (C

GR

)

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Initially , CGR was found higher in TP crop due to higher number of plants per unit area. In later phase (60 DAG), CGR in SRI crop was still increasing, while in TP crop, it started decliningThe increase in CGR in SRI crops was mainly due to maintenance of leaf area (lower leaf senescence)

Lower rate of leaf senescence is due to larger amount of cytokinins transported from roots (root exudates)

SRI had higher chlorophyll content, and maximum quantum yield of PS II (Fv/Fm) and actual quantum yield (Φ PS-II) compared to RMP crop show better light utilization

Similarly, crops under SRI showed higher photosynthetic rate (23.15 vs. 12.23 μ mol m-2 s-1 in RMP) and lower transpiration rate (6.41 vs. 7.59 m mol m-2 s-1 in RMP), which indicates SRI plant is more efficient in water-use than transplanted rice plant

Parameters SRI RMP Computed-t

Ave. panicle number (hill-1) 16.9 ± 1.23 8.6 ± 0.59 6.040

Panicles (m-2) 421.7 ± 4.02 430.0 ± 5.46 -1.229 ns

Ave. panicle length (cm) 21.61 ± 0.18 18.77 ± 0.21 10.090

Grains/panicle 141.9 ± 2.88 84.2 ± 1.68 17.377

Unfilled grains/panicle 9.80 (6.9) 8.17 (9.7) 4.256

Ripened grains (%) 93.1 90.3 --

1000-grain wt (g) 22.46 ± 0.14 20.68 ± 0.14 8.964

Grain yield (t ha-1) 6.38 ± 0.06 4.49 ± 0.05 24.292

Yield and yield-contributing characters

Results showed that SRI crop had more number of longer panicles, greater number of grains in spikes, higher 1000-grain weight, and more grain- ripening percent than in TP crop mainly responsible for higher grain yieldWate

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Distribution of panicles according to their length under SRI and TP

Short: >10 cm - 17 cm Medium: 17.1 cm - 20 cm Long: 20.1 cm - 24 cm Extra-long: 24.1 cm - <26 cm W

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Panicle length

Grains per spike

Grain filling

Roots growth and activity

Canopy development

Light utilization

Higher yield in SRI

Tiller number

Panicle number

Units SRI RMP

Kg per kg seed 797.13 59.83

Kg per kg fertilizer 12.99 9.14

Kg per man-days 35 23

Kg per ha land 6377 4487

Liter water per kg 1571 2801

Estimated average productivity of inputs on SRI and RMP

Seed

Fertilizer

Labour

Land

Water

Money per ha (Rs.) 25009 12115

SRI enhances paddy yields, increasing returns and saving labour and water. The productivity of the key inputs is raised with more output of paddy per unit of seed, fertilizer, labour and water.

Grain yield (t/ha)% increase

with SRISRI Farmers’

practices

Kharif 2007 5.03 2.87 75%Rabi 2008 5.50 2.50 120%Kharif 2008 5.31 2.19 142%

On-Farm Demonstration Variety: SurendraSpacing: 20cm x 20cm

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Farmers Training on SRI at WTCER Farm on 3rd Nov., 2007

Training on “System of Rice Intensification” to various line department personnel under national-level training programme at WTCER, Chandrasekharpur, Bhubaneswar.

Seven one-day training programmes conducted for farmers of Daspalla (Nayagarh district), Nimapara (Puri), and Balipatna (Khurda district) on various aspects of SRI

Training given to 50 farmers on SRI under “Scaling of water productivity in agriculture for livelihood,” 12-18 March, 2008 at Deras Research Farm, WTCER, BhubaneswarW

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Future Research Needs

Biochemical and hormonal changes inside the plants responsible for changes in physiological processes and phenotypic alterations in SRI plants need to be studied

Changes in soil-root environment that occur with SRI due to aerobic field condition need to be addressed for future research

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Future Research Needs

There is a need to conduct studies on nutrient-budgeting in SRI.

Initial findings have indicated that SRI is drought-tolerant, so a critical experiment will be to assess and establish this fact

For kharif season, there is need to develop a system to deal with stagnant water on SRI fields so that rice yields and water productivity can be enhanced

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Limitations for SRI

Resistance to acceptance of SRI

Lack of training and extension facilities

Absence of proper water management Lack of well-leveled field topography Weed management (cono-weeder)

Erratic power supply

In spite of greater adoption in 33 countries around the world with benefits to farmers, SRI still faces criticism due to fundamental knowledge gaps and lack of studies to address the synergies of individual SRI components.

McDonald et al., Field Crops Research, 108:188-191 (2004),Reported that there is no evidence that SRI outyields BMPs beyond Madagascar – this statement is contestable

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Dr. Amod K. ThakurWater Technology Centre for Eastern Region (ICAR)

Bhubaneswar

SRI: Still has a long way to go…SRI: Still has a long way to go…

Thanks