irrigation and fertigation control - purdue university

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Irrigation and Fertigation ControlMarc van Iersel

Irrigation: Why worry?

• Overlooked, but critical task

• Has major impact on quality

• Affects fertilization

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What determines water use?

• Plant size

• Environmental conditions

Two components to water use

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High water use Low water use

Transpiration and stomates

Stomatal opening depends on light

VPD

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Vapor pressure deficit

Temperature (oFahrenheit)

30 40 50 60 70 80 90 100 110

Vap

or p

ress

ure

(kilo

Pas

cals

)

0

1

2

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7

Saturation vapor pressure



30 40 50 60 70 80 90 100 110

Vap

or p

ress

ure

(kilo

Pas

cals

)

0

1

2

3

4

5

6

7

Saturation vapor pressureActual vapor pressure (40% RH)

VPD

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30 40 50 60 70 80 90 100 110

Vap

or p

ress

ure

(kilo

Pas

cals

)

0

1

2

3

4

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7

Saturation vapor pressureActual vapor pressure (40% RH)Vapor pressure deficit (40% RH)

VPD

Irrigation practices

• Based on grower judgment• Likely results in overwatering

• Timers• Don’t adjust for crop size or weather

• Light or VPD accumulator• Doesn’t adjust for crop size

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This project is all about water

Providing real‐time information to growers

About their microclimatic conditions

To schedule irrigation applications

Based on specific crop requirements

SCRI-MINDS Managing Irrigation and Nutrition via Distributed Sensing

What we have done:• Developed Wireless Sensor Networks, with

monitoring and control capabilities (hardware)

• Developed a Graphic User Interface, for intuitive decision making (software)

• Developed guidelines to Manage Irrigation

• Quantified impact on production (Quality, fertilization, runoff)

• Determined the Economic Impact of better irrigation management ($$$)

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What is a Wireless Sensor Network?

Production areasIrrigation Controller

Sensors Valves

RadioCommunication

Local Computer

Grower Input

Graphic user interface

Remote Computeror Smartphone

What is a Wireless Sensor Network?

• Hardware • Sensors• Nodes• Valves

• Software• Data visualization• Decision making

nR5

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SolenoidValve

H2O

DRY! GOOD !

Automated Irrigation System

Observed benefits

• Water savings• Plant quality• Faster growth• Fertilizer savings• Environmental

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Precision Control of IrrigationWater use reductions between 40 and 85%

Precision Control of Irrigation

• A 50% reduction in irrigation saved over 43 million gallons of water in one nursery in 2012

• Saved $6,500 in pumping costs

• In California (water costs are ~$750 / acre foot), this water costs ~$100,000

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Impact on Water Availability

• Cost of water is low compared to other variable costs

• Some operations are limited by the well or pump capacity

• Tree nursery was able to install an additional 30-acre production

Cut Snapdragons (Flowers by Bauers)

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0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

GROUP 1/2 GROUP 2 GROUP 2/3 GROUP 3 GROUP 3/4

82%

32%39%

31%

5%

Economic Analysis: Total Stems

Pre-Sensor: (2007 – 2009) Post-Sensor: (2010 – 2012)

Lichtenberg et al, 2015

$0.00

$0.10

$0.20

$0.30

$0.40

$0.50

$0.60

$0.70

GROUP 1/2 GROUP 2 GROUP 2/3 GROUP 3 GROUP 3/4

Economic Analysis: $ /stem



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2007 -2009 2010- 2012 Difference Change

Crops/ year 37 38 1 3 %

Stems/ year 106,308 139,382 33,074 31 %

Price/ stem $ 0.59 $ 0.62 $ 0.03 5 %

Labor costs $ 15,905 $ 17,893 $ 1,988 12 %

Electricity $ 4,109 $2,923 $ 1,186 -29 %

Sensor system $ 0 $7,147 $ 7,147 ---

Revenue $63,094 $ 85,679 22,585 36 %

Profit $43,080 $57,716 $14,636 34 %

Payback period on upfront costs <16 months

Economic Analysis: Annual Profitability



• Increased yields • Improved quality

= more profit

Cut Snapdragons (Flowers by Bauers)

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Alternative to Plant Growth Regulators

• Reduced substrate water content reduces elongation

Tracking curves to monitor poinsettia height

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25‐Aug 1‐Sep 8‐Sep 15‐Sep 22‐Sep 29‐Sep 6‐Oct 13‐Oct 20‐Oct 27‐Oct 3‐Nov 10‐Nov 17‐Nov 24‐NovHei

gh

t fr

om t

he

Ben

ch T

op (

inch

es)

Date

Cultivar: Classic Red

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0 20 40 60 80

Height (inches)

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Days after pinching

0 20 40 60 80

Height (inches)

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208

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Lower limit

Upper limits

Height

8

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2014"

17"

15.5"

Control

Growth tracking curves

Days after pinching

‐20 0 20 40 60 80

Substrate volumetric water content (%)

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20

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40

5017"

‐20 0 20 40 60 80

Control

10

20

30

40

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14" 15.5"

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Final plant height35.6 cm 39.4 cm 43.2 cm control

Bract size35.6 cm 39.4 cm 43.2 cm control

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Better Growth

Month

Feb

201

1

Mar

ch 2

011

Apr

il 20

11

May

201

1

June

201

1

July

201

1

Aug

ust

201

1

Sep

t 20

11

Oct

201

1

Nov

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1

Dec

201

1

Jan

2012

Feb

201

2

Mar

ch 2

012

Apr

il 20

12

Num

ber

of p

lant

s

0

2000

4000

6000

8000

10000

Forecast sales

Faster production cycle

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Month

Fe

b 20

11

Mar

ch 2

011

Apr

il 20

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May

20

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Jun

e 20

11

July

20

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Au

gust

20

11

Sep

t 20

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Oct

20

11

No

v 20

11

De

c 20

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Jan

2012

Fe

b 20

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Mar

ch 2

012

Apr

il 20

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Num

ber

of p

lant

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0

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Forecast salesActual sales

Faster production cycle

23,400 plants

New Crop - 2012

Ready Oct. 20124 month

production cycle

Is it real?

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Disease Management

• Sensor-based irrigation decreased disease-related shrinkage in Gardenia from 30% to virtually zero

Profitability of Wireless Sensor Networks

Potential benefits found include:• Water/energy/labor savings• Reduced losses• Reduced management time• Accelerated production time

Analysis by Erik Lichtenberg, Univ. of Maryland

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No Sensors

Sensor-Based

Irrigation

Annualized Revenue $66,297 $ 145,505 Annualized Production Expenditures $30,539 $50,039 Annualized Sensor System Cost (3-year Lifetime, 6% Interest) $ 0.00 $3,755

Annualized Profit $35,758 $91,710

Annualized Profit per Acre $78,000 $ 200,000

Percent Change from Base Case +156%

System payback: less than one month!

Water & fertilizer interactions

• Fertigation; water soluble fertilizer• excessive irrigation result in high fertilizer

application • Excessive watering leaches nutrients from

containers• Nutrients movement in the substrate:

• mass flow • diffusion

• dependent on water in the substrate

• Thus plant nutrient uptake depends on substrate water content

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Bigger plantsless flowers

Bestplants


• Can fertilizer concentrations be decreased with more efficient irrigation?

• Because of less leaching

• Or do fertilizer concentrations need to be increased?

• Because less water is applied

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Materials and methods

• Petunia ‘Apple blossom’ was grown in 6” pots

Treatments

• Fertigation at two fertilizer concentrations100 and 200 ppm N (15–5–15 Cal-Mag)

• Soil moisture sensor-based drip irrigation system used

Solenoid valve

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Treatments

• Four irrigation treatments (volumes): • Control,• Low,• Medium &• High leaching

• Leachate collected weekly

Data collection

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Irrigation volume

Control Low Medium High

Tot

al le

achi

ng v

olum

e (m

L/p

lant

)

0

500

1000

1500

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3500

100 mg·L-1

200 mg·L-1

b

ab

a

aFertilizer Nconcentration

Leaching volume

Irrigation volume


Sho

ot d

ry m

ass

(g/p

lant

)

0

20

40

60

100 mg·L-1

a aa a

Shoot dry mass

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Irrigation volume


Sho

ot d

ry m

ass

(g/p

lant

)

0

20

40

60

100 mg·L-1 200 mg·L-1

b bb

b

a aa a

Shoot dry mass

CONCLUSIONS

• Irrigation and leaching volumes did not affect plant growth

• No evidence fertilizer concentrations can be reduced with more efficient irrigation

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Reduced fertilization

• Water-soluble fertilizers:• Less water = less fertilizer

• CRFs: • Less water = less leaching

• Less runoff

• Financial savings $5 – 10 million/year in Georgia alone

Towards commercializationDecagon’s PlantPoint system, being released now

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http://horttech.ashspublications.org/content/23/6.toc

HortTechnologySpecial Series:

Improving Irrigation with Sensor Networks:Implementation and Impact

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Low-cost alternative: Arduino

http://hortphys.uga.edu/irrigationcontrol.html

Build your own irrigation controller• Open source microcontroller (Arduino)

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http://hortphys.uga.edu/irrigationcontrol.html

Environmental Benefits

50% industry adoption rate in the ornamental industry:• Save enough water for 400,000

households a year• Prevent 620,000 lbs. of nitrogen and

400,000 lbs. of phosphorus from entering the environment

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Benefits

• Control over plant quality

• Reduced disease pressure

• Less leaching and runoff

• Water and fertilizer savings

• Higher profits

Funding provided by

USDA‐NIFA‐SCRI Award no. 2009‐51181‐05768

SCRI-MINDS Managing Irrigation and Nutrition via Distributed Sensing

irrigation and fertigation control - purdue university

Documents