Tea and Irrigation

8/12/2019 Tea and Irrigation

1/14

13/07/20

Responses of Low Grown Tea to

Irrigation

S.N.Bandara

Agronomy Division

Tea Research Institute

Ratnapura

Drought & Climate Change

Climate change

1. Temperature rise

2. C-3 type crop

3. Island nature

4. Mountainous area

5. Tea vegetative crop

2

Drought

1. Soil moisture depletion - PWP

2. Temperature rise - >350C

3. Vapor pressure deficit - >2KPa

1921 2010

Picture: Mt. Everest Nepal


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Young Tea Water Stress Coefficient

3

Ks Water Stress Coefficient

TAW Total Available Water

Dr - Depletion rate

P fraction of TAW plant can use

(for tea, p = 0.4)

Is there a moisture stress?

Water Stress Coefficient - Ratnapura 2010

4

2010 very

wet year

with

annual

rainfall of

4983mm.

Still there

are some

moisture

stress

periods.

Month - 2010

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Rainf

all(mm/day)

0

20

40

60

80

100

120

140

160

180

Waterstresscoefficient(KS)

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Rain

Ks


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Different Irrigation Practices

5

-manual irrigation

-small sprinkler

-high labor cost

-delayed irrigation

-low monitoring

6

MethodologyNetafim Ram 17D inline drip system

Application rate 1.6L/hr

TRI 2023 & TRI 3025 cultivars

1999 May planting

Harvesting commenced 2001 Oct

Irrigation during January-March

Graze period 5 con. rainless days

Based on Class A pan evaporation


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Physiological

response.,

7

33 and 38% higher

photosynthesis under irrigation

for TRI 2023 and TRI 3025

Rainfall(mm/week)

0

20

40

60

80

100

Photosynthesis(mmolm-2s-1)

0

2

4

6

8

10

12

14

16

irigated

rainfed

Week no

0 2 4 6 8 10 12

0

20

40

60

80

100

0

2

4

6

8

10

12

14

16

irrigated

rainfed

Leaf temperature

8

TRI 3025 leaf temperature

rapidly build up than TRI

2023

At 1400hrs, ~100C

difference between irrigated

and rain-fed plants

Time (hours)

600 800 1000 1200 1400 1600 1800 2000

Temp

erature(0C)

20

25

30

35

40

45

TRI 2023 irrigated

TRI 2023 rainfed

TRI 3025 irrigated

TRI 3025 rainfed

air temperature


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Temperature effect on

photosynthesis

9

TRI 3025 more sensitive to

increasing ambient

temperature even under

irrigation

Photosynthesis(molm-2 s-1)

0

2

4

6

8

10

12

14

irrigated y = 36.9 - 0.76x (r2=0.11, P=0.4)

rain-fed y = 92.2 - 2.44x (r2=0.75, P=0.005)

Max. air temperature (0C)

33 34 35 36

0

2

4

6

8

10

12

14

irrigated y = 71.8 - 1.83x (r2=0.57, P=0.03)

rain-fed y=101-2.75x (r2

=0.75, P=0.005)

TRI 2023

TRI 3025

Tea yield

10

Madetea(kg/ha/week)

0

50

100

150

200

TRI 2023 irrigated

TRI 2023 rainfed

MonthJan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0

50

100

150

200

TRI 3025 irrigated

TRI 3025 rainfed

Graph shows weekly tea

yield for each month

There are some months

with high yield fluctuation

Effect of irrigation on tea

yield observed even

during wet season


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Yield analysis

11

TreatmentYield (Made

tea kg/ha)TRI 2023 rain-fed 4468(327)

TRI 2023 irrigated 5650(220)

TRI 3025 rain-fed 4176(137)

TRI 3025 irrigated 4859(160)

Significance

Cultivar 0.0009

Irrigation 0.0001

Cultivar X

Irrigation0.24

12

Variable

TRI 2023

rain-fed

TRI 2023

irrigate

TRI 3025 rain-

fed

TRI 3025

irrigate

slope P slope P slope P slope P

Tmin 6.1 0.27 13.0 0.02 4.5 0.32 9.6 0.06

Tmax -28.8


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13

Stem canker infection

Irrigation reducedthe infection ~80%

TRI 2023 highly

vulnerable

Treatment

TRI2023

rain-

fed

TRI2023

irriga

ted

TRI3025

rain-

fed

TRI3025

irriga

ted

Infectedpopulation(%)

0

20

40

60

80

100

severe

moderate

less infection

no infection

14

Year

Increased yield Income (add.) Cost (add.) Net revenue Discount

Factor

(10%)

NPV

TRI

3025

TRI

2023

TRI

3025

TRI

2023

TRI

3025

TRI

2023

TRI

3025

TRI

2023

TRI

3025

TRI

2023

Investment cost 1 -515,841 -515,841

1999/00 7433 7433 -7433 -7433 0.91 -6757 -6757

2000/01 5011 5011 -5011 -5011 0.83 -4141 -4141

2001/02 8071 10498 417271 542726 170027 219165 247244 323560 0.75 185758 243096

2002/03 5873 12802 303634 661843 125192 265496 178442 396347 0.68 121879 270710

2003/04 1908 3902 98644 201754 47381 87767 51263 113987 0.62 31830 70777

2004/05 3254 5448 168232 281646 72349 116771 95883 164875 0.56 54123 93067

2005/06 203 1148 10495 59349 7284 26419 3211 32930 0.51 1648 16898

2006/07 2606 5318 134730 274923 64547 119458 70184 155465 0.47 32741 72526

2007/08 1121 9993 57956 516623 28546 208198 29410 308425 0.42 12473 130802

2008/09 2691 2052 139125 106088 65490 52550 73635 53539 0.38 28390 20641

Net Present Value (Rs) -57898 391779

NPV analysis for TRI 2023 and TRI 3025


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15

Extent

(ha)

Unit

cost

TRI 3025 TRI 2023

0% 5% 10% 15% 0% 5% 10% 15%

1 515841 25255 -93529 -247476 -369983 638180 360259 13706 -244545

2 452921 88175 -30609 -184555 -307063 701101 423180 76626 -181624

5 413168 127927 9144 -144803 -267310 740853 462932 116379 -141872

10 363168 177927 59144 -94803 -217310 790853 512932 166379 -91872

20 343168 197927 79144 -74803 -197310 810853 532932 186379 -71872

Sensitivity analysis - land

35 40 45 50 55 60 65 70 75

-500

0

500

1000

1500

2000

0%

5%

10%

15%

Net

PresenValue(Rs.000)

-500

0

500

1000

1500

2000

Green Leaf Price (Rs/kg)

35 40 45 50 55 60 65 70 75

-500

0

500

1000

1500

2000

Rs 405/day

Rs 700/day

Rs 500/day

TRI 3025

TRI 3025

TRI 3025 TRI 2023

TRI 2023

TRI 2023

16

Sensitivity

analysis for

wage rate at

different green

leaf prices


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Results of Drip/Sprinkler Trial

Yield 2008

17

Sprinkler Drip Control

MadeTea(Kg/ha)

3000

3500

4000

4500

5000

5500

Diurnal photosynthetic rate

18

Time (hours)

600 800 1000 1200 1400 1600 1800

Photosy

nthesisrate

0

2

4

6

8

10

12

14Sprinkler

Drip

Control


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13/07/20

Diurnal temperature

19

Time (Hours)

600 800 1000 1200 1400 1600 1800

Temperature(0C)

24

28

32

36

40

44

48Sprinkler

Drip

Control

Root Development

20

0 10 20 30 40 50

-60

-40

-20

Dens ty ( g m-0 1 2 3 4 5

Depth(cm) -60

-40

-20

rainfed

drip

sprinkler

Fine roots

Root development was

studied on a parallel drip

sprinkler experiment.


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13/07/20

Conclusions

21

Response depends on cultivar

High yield observed during wet

season

High temperature limits

photosynthesis as well as yield

No reduction in root development

Drip irrigation economical only with

high productive cultivars

Implications to industry

22

Alternative solution to mitigate drought effect and threat

posed by climate change

Main factor availability of water sources

Cost effective irrigation solutions are available

Based on severity of water stress, young plant deaths and

productivity, irrigation can be considered as alternative for

improved performance

New technology, like GIS can be used to identify potential

areas for irrigation


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13/07/20

Mobile irrigator

Low cost mobile irrigation

system with gun sprinkler

Irrigation head cost

approximately Rs 15000.00

Can be operated with

common 2 kerosene pump

Application area ~ 1000m2

2010 Feb

23

Weather Forecasting

24

To sense future weather patterns

Important in deciding applications like

fertilizing, planting, irrigation etc.,

Department of Meteorology, Sri Lanka

www.meteo.gov.lk

Weather forecasting websites

www.noaa.gov

www.accuweather.com

www.intellicast.com
http://www.meteo.gov.lk/http://www.accuweather.com/http://www.accuweather.com/http://www.accuweather.com/http://www.accuweather.com/http://www.meteo.gov.lk/


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Department of Meteorology, Sri Lanka

www.meteo.gov.lk

25

Weather forecasting websites

www.accuweather.com

26


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13/07/20

Weather forecast for LINDULA and

PASSARA, Sri Lanka

27

28

Thank You

Acknowledgement:Tea Research Board of Sri Lanka

The University of Adelaide

Dr. Ian Nuberg

Prof. W.A.J.M de Costa

Prof. Glen McDonald

Dr. Anne McNeil

Documents

Tea and Irrigation