Alternate wetting and Drying in rice (AWD) and its adoptation

Shantappa Duttarganvi

shantud4@gmail.com

8499034130

RICE IS LIFE Cultivate more land with less water

Introduction

Rice

India• Area: 44mha• Production: 104mt• Productivity: 2001kg/ha

AP• Area: 43.7 Lha• Production: 140 Lt• Productivity: 3032kg/ha

Share of major paddy producing states

DES, 2009

Pressure to produce more food (rice) because of ever increasing population

In 2020, the world needs to produce

an additional 50-80 M tons of paddy rice

UN, 2004 (Wikipedia) = 125-200 km3 of water

But also: More people means• more industry• more drinking water• more sanitation water• more swimming pools• more cars to wash• more gardens to sprinkle• more…

=> Water is getting scarce and expensive

Water: A Global Issue

‘too little, Too much, or too dirty’

• 1.3 billion without safe water supply• 2 billion without sanitation• 800 million malnourished• Thousands killed by floods• Every day reports on water related

issues

Extreme Scarcity<500

Scarcity500-1,000

Stress1,000-1,700

Adequate1,700-4,000

Abundant4,000-10,000

Surplus>10,000

Ocean/Inland Water

No Data

m3/person/year

Water Availability: 1975

Water Availability: 2025

Future is going to be even uncertain interms of rain fall, ground water and surface water

Periodicity, intensity and distribution of rain fall is going to change

Climate Change: Another complexity

70% water used for irrigation globally

Rice uses > 80% water in many countries

3-5,000 litres to produce one kg

Rice and water

Crop water use

=1kg 1,500 - 3,000 litres water

=1kg 3,000- 5,000

litres water

=1kg 3,000 – 5,000 litres water

So, we eat, wear, drink.. water…

Objectives of the Session

Produce more rice with less water

Bouman, 2001

Components of water balance in rice fields

Water-saving measures

• Puddling and Land leveling

• Crack plowing

• Alternate wetting and drying

• Communal seed beds

• Efficient use of rainfall (cropping calendar)

• Direct wet seeding

• Aerobic rice

• Pressurized irrigation

Yield

Low High Water availability

Flooded lowland

Upland

Crack plowingCompactionGood puddling……..

‘Safe’ AWD

Aerobicrice

various response options to water scarcity

Diversification(non rice crops)

Construct afield channel for irrigation

Before puddlingharrow to close

the cracks

Maintain bunds,seal cracks, andclose rat holes

Make a farmditch for proper

drainage

Ensure goodfield levelling

Irrigate up to5 cm, maximum

Ways to use water wisely

LAND PREPARATION

Cracks favour rapid “by-pass flow”

Shallow tillage to remove cracks

Soaking prior to puddling

Thorough puddling

Plot to plot irrigation removes valuable nutrients

During land preparation, Bulacan, Phillipines, Cabangon and Tuong (2000)

Control Cracks Ploughed

PERFECT LEVELING IS ESSENTIAL

• Uneven crop growth

• Uneven fertilizer distribution

• Extra weed problems

BUND PREPARATION AND MAINTENANCE

• A reduction of 450 mm of total water use

IMPROPER LEVELING LEADS TO….

METHODS OF WATER APPLICATION

Continuoussubmergence

•Less supervision

•Less expenditure on weed control

• Saves irrigation water• Minimizes the formation of

toxic substances• Lessen drainage problem

Continuous saturation

• More weeds • Water saving

Intermittent submergence

Continuous submergence

• High water requirement

3000–5000 liters of water to produce 1 kg of rice

• Environmental degradation • Reduces fertilizer use efficiency• Destruction of soil aggregates• Anaerobic fermentation of soil

organic matter: Methane emission

AWD: ‘intermittent irrigation’ or ‘controlled irrigation’

Alternate flooding: Number irrigations reduced without reducing yield

AWD period vary based as rainfall pattern, climatic condition, depth of water and texture

Plant roots have access to hidden water in root zone

Compared with the traditional continuous flooding system, AWD can reduce water input by 15-30% without yield loss

Alternate Wetting and Drying (AWD)

PI to completeflowering

grain filling

MaturityLate tillering

Earlytillering

transprecovery

Field water depth (cm)

-10

-5

0

2.5

5

60

-20

-15

0 10 20 30 40 50 60 70 80 90 100 110

CF

AWDSoil surface

Days after transplanting

flowering

Safe AWD

Safe AWD when: Soil Tension at 15 cm soil depth > - 10 kPa

Using tensiometer: To measure moisture availability of the soil for crops (expressed as soil tension)

A practical indicator to irrigate under safe AWD

• Safe AWD = Irrigate when water depth ~ 15 cm• Keep flooded 10 DAT (weeds) and at flowering

Simple key messages for farmers Simple tool that help farmers decide when to irrigateFarmers can experiment with threshold levels

Key points of AWD • Transplant young seedlings into puddled

soil • Install a PVC pipe with holes • Start AWD at 10 DAT and allow the field

to dry out• Re-flood the field to a standing water layer

of 5 cm when the groundwater is 15-20 cm below the soil surface

• Keep a standing water layer of 5 cm for 1 week at flowering

• Continue AWD cycles after flowering until harvest

• Scope for 10, 20, 25 and 30 cm with different genotypes and different location

YIELD AND WATER USE OF AWD AND CONTINUOUSLY FLOODED CONDITIONS

1.201.34

602518

7.27.7

Flooded AWD

2001Munoz, Philippines, (Belder et al 2004)

0.921.07

878802

8.18.4

Flooded AWD

2000

0.900.95

965878

8.48.0

FloodedAWD

1999Tuanlin, Huibei, China (Belder et al 2004)

Water productivity (g grain kg-1

water)

Total water input (mm)

Yield (t ha-1)

TreatmentYearLocation

BOUMAN et al. (2006)

-No yield difference between AWD and farmers’ practice-Farmers achieved 16-30% savings by adopting AWD-Increased net profit- reduced competition of water between households and rice farming.

Irrigation water used (mm)Yield (t/ha)

AWD AWD

Results

AWD Promotes higher zinc availability

soil

Zn

(m

g/k

g)

AWD vs. CF:

•higher redox (i.e. more oxidized)•higher Zn availability

In the soils :

Better root anchorage to reduce lodging

Continuous flooding (CF)

AWD 1

AWD 2

AWD 3

Time

48 h 48 h

Flooding for 1 week

Fiel

d W

ater

leve

l

N2O & CH4

g CO2 eq./m2/season

500

1,440

390-540

390

Hosen et al. unpubl.

4. AWD reduces methane emissions!

Precautions

• Sandy, salt affected soil• Levelled land• Weed problem• Flowering

Reduced total pumping cost and labor

Better rooting system: lodging have been reduced

Mechanized harvesting

Soil sterilization: Rice plants have less pest population

Grain quality will improve

Knowing the concept of AWD, they do not worry even if the rice field do not have water

Perceived benefits of AWD by farmers

Thank u