Optimization of Water 2 Consumption by Smart Farming Water - - PowerPoint PPT Presentation

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Sharif University

• f Technology

Electrical Department Hosein Pourshamsaei Supervisor: Dr. Amin Nobakhti

Optimization of Water Consumption by Smart Farming

In The Name of God

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Contents

 Water consumption in agriculture  Smart farming  Soil moisture measurement  Sensor placement  Actuation  Control strategy  Challenges

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92 % 2 % 6 %

IRAN WATER USESE

AGRICULTURAL INDUSTRIAL DOMESTIC

Water consumption in agriculture

• Iran water usage in agriculture is %22 above world average
• Food and Agriculture Organization (FAO) reports in 2000:

Efficiency of water consumption in agriculture: Libya: %60 India: %54 Egypt: %53 Syria: %45 Pakistan: %44 Arabia: %43 Turkey: %40 China: %36 IRAN: %35

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Smart farming

 We focus on sensing

technology, including:

• What quantities are

needed to measure

• Method of measurements
• Standards and reliability
• Sensor placement
• Extendable
• Cost

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29/09/1438 2 Soil moisture measurement

 Definitions:

• Soil water content
• r
• Soil water potential

Amount of work per unit quantity of pure water that must be done by external forces to transfer reversibly and isothermally an infinitesimal amount of water from the standard state to the soil at the point under consideration.

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Soil water potential

 A difference in water potential between two soil

locations indicates a tendency for water flow, from high to low potential.

 Soil water potential describes the energy status of the

soil water and is an important parameter for water transport analysis, water storage estimates and watering time plan. ψ ψ ψ ψ ψ

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Soil water potential

 - pressure potential  Energy per unit volume of water required to transfer

an infinitesimal quantity of water from a reference pool of water at the elevation of the soil to the point

• f interest in the soil at reference air pressure and

temperature.

 If soil is saturated, ψ is positive and If the soil is

unsaturated, ψ is negative.

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Soil water potential

 m easurem ent 

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29/09/1438 3 Soil water potential

 - gravitational potential

Energy per unit volume of water required to move an infinitesimal amount of pure, free water from the reference elevation () to the soil water elevation ().

 - solute potential

always negative since defined relative to pure water.

 - air pressure potential

Accounts for changes in air pressure, different than the reference pressure (atmospheric pressure).

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Soil water content measurement methods

 Direct method  water content may be determined indirectly by

various radiological techniques, such as neutron scattering and gamma absorption

 Soil water dielectrics:

permittivity or “dielectric constant”, is for liquid water about 20 times larger than that of average dry soil, because water molecules are permanent dipoles.

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Soil water dielectrics

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Soil water content or potential?

 Soil water content measurement has lower cost  For sprinkle watering soil water content is better.  For pipe watering water potential is better  For a specific soil, both are equivalent:

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29/09/1438 4 Sensors placement

 Finding optimal sensors number and placement is

important, since:

Cost constraints Maintenance issues Precision: sensors must be placed in a typical spot,

no wettest or driest

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Actuation

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 Possible actuators:

• Human!
• Solenoid valves on pipe paths
• Sprinkles

Control strategy

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 Daily watering:

• Selecting each day of the week for watering to occur.

the total run time should be split up among several start times. For example twenty minutes a day could be programmed to be four start times for five minutes each.

• Schedule at least one hour of time between cycle

starts.

 Programmed days:

• irrigation can take place only on selected days or

hours.

Challenges

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 Cost  Sensor placement  Reliability and maintenance  Agricultural knowledge

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