Irrigation

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Irrigation

• Chapter 7

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What is irrigation?

• the controlled application of water
• xerophytes, mesophytes, hydrophytes

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What is transpiration?

• plants give off water in the form of a gas
• 99 of water is transpired

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What is Transpiration Ratio?

• pounds of water transpired for each pound of dry
  matter produced (table page 74)

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What is water use efficiency?

• pounds of dry matter produced per inch of water
  used

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What is an inch of rain mean?

• enough water to cover an acre with 1" of water
• not all water is used by the plant (evaporation,
  runoff etc)

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How do growing conditions affect water
requirements for plants?

• high wind or temp more water
• disease more water
• seedling development less water
• crop maturity less water
• nitrogen encourages water use

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What is climate?

• the amount of water throughout the season

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What is the climate in Northeast Montana?

• semi-arid 10-20" moisture/year

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How is water measured for irrigation?

• Gallon
• Acre-feet one acre (43,560 ft) one foot deep
• Barrel 42 gallons
• Cubic Feet

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What is Flow?

• given amount of water in a specific time
• GPM, CFS, CFM, Barrels/day
• Example
• 100 acres
• apply 8" water
• pump delivers 900 GPM
• how long do you need to run the pump to get 8"
  water?

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Answer

• 100 acres x .66' 66 acre feet
• (66 43,560) 2,874,960 CF
• 2,874,960 7.48
• 21,504,700 gallons
• 21,504,700 / 900 23,894 min or 16.5 days at
  24 hrs/day

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What are the types of irrigation?

• Surface Irrigation
• Wild Flooding- hay
• Furrow Irrigation - sugar beets
• Subsurface Irrigation - water from underground
• Aerial Irrigation
• Sprinkler - center pivot, line, wheel line
• Drip or Trickle - water applied directly to plant

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What is moisture stress?

• plants do not get enough water

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How do plants deal with moisture stress?

• 1) tolerate - do not grow as tall
• 2) escape - shorten life cycle
• 3) avoid - store water, roll up leaves

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How can we reduce moisture stress?

• reduce weeds (competition)
• less seed (competition)
• balance fertilizer

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