1. IAFNR Plant and Soil Sciences Module
Soil Irrigation
IAFNR Plant and Soil Sciences Module

2. What’s with Water? Covers ¾ of the earth’s surface
Major part of the bodies of plants and animals
Formed from two gasses, Hydrogen and Oxygen.
H2O- two Hydrogen atoms and one Oxygen atom
Exists in three forms
Liquid- between 32º and 212º F
Gas or Vapor- above 212º F
Solid- below 32º F
Universal Solvent
Can dissolve almost everything
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3. The Water Cycle
The water cycle (or hydrologic cycle) describes the continuous movement of water throughout the surface of the earth and the atmosphere. As you can see from this diagram water also changes its form throughout the cycle.
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4. Did you know water was responsible for these actions in plants?!
Role Of Water in Plants
Water performs vital functions in plants
Necessary for all living plant cells and tissues
Medium and solvent for nutrients in soil
Chemical reactant for metabolic processes
Like photosynthesis
Responsible for stiffness in cell
Function for stomata and cell expansion
Coolant and Temperature buffer
Did you know water was responsible for these actions in plants?!

5. Which classification of plants thrive in
Do you Remember?
Which classification of plants thrive in
flooded conditions?
dry conditions?
Answers…
Hydrophytes
Xerophytes

6. Precipitation Water in the form of rain, snow, sleet, or hail
Meteorologists use probabilities to indicate that degrees of confidence for precipitation to occur in a given area.
Forecasts are important to management decisions for
Planting
Harvesting
Irrigation

7. Water in Plants Water Loss Water Storage Water Movement
Directly proportional to the surface area (leaf area) exposed to air
Water passes in and out of leaves as vapor
When plants lose more water than they bring in they wilt
Plant adaptions and management practices to minimize loss
Desert plant with small leaves
Farmers fallow fields
Water Storage
Stored in soil
Capillary water
Used by plants and moves freely through the soil
Water Movement
Translocation- from soil through plant
Transpiration- evaporation from leaf and plant surfaces
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8. Water in Soil Evapotranspiration Percolation Irrigation
Total water lost through evaporation from the soil surface and from transpiration through the plant
Directly related to crop yields
Percolation
Movement of water through soil layers of material
Irrigation
Can provide the optimum amount of water for soils to avoid excess loss from Evapotranspiration
Needs to be managed properly to avoid percolation

9. irrigation Irrigation
Applying water to crops in such a way as to keep them wet but not too wet
Optimal rainfall reduces the requirement for irrigation
Used to ensure a productive crop
Requires management and knowledge of precipitation and Evapotranspiration
There are multiple methods of irrigation systems
Selection depends on land slope, soil water intake, water holding capacity, water tolerance, and effect of wind
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10. Flood Irrigation Used where land is level
Often used for orchards, vineyards, cereal grains
Water enters through a head ditch and released into checks by siphons, gates, and valves.
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11. Furrow Irrigation Widely used method for crops
Water runs down furrows between plant rows
Water is more uniformly applied and allows for uniform maturity of crops
Efficient, but very expensive
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12. Sprinkler and Drip Systems
Widely used method of irrigation
Sprinkler
Uses sprinklers on hand lines, wheel lines, and center pivots (see photo)
Can be adjusted for water application rates, sprinkler spacing, and droplet size
Drip
Uses line source or point-source emitters
Can be underground or on plant surface
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13. Irrigation Efficiency and Timing
15% of irrigation water is lost to evaporation in sprinkler systems
Drip systems are more efficient because they are not affected by evaporation
Drip rated at 90% efficient
Sprinkler at 75%
Furrow system is very efficient, but also very expensive
Timing
To determine when irrigation is needed, manager needs to be aware of
soil moisture
Multiple ways to test for this
Climate and precipitation

14. References
Parker, R. (2010). Plant and Soil Science: Fundamentals and Applications. Clifton Park, NY: Delmar.