What is irrigation?
the controlled application of water
What is transpiration?
plants give off water in the form of a gas
99% of water is transpired
What is Transpiration Ratio?
pounds of water transpired for each pound
of dry matter produced (table page 74)
What is water use efficiency?
pounds of dry matter produced per inch of
What is an inch of rain mean?
enough water to cover an acre with 1" of
not all water is used by the plant
(evaporation, runoff etc)
How do growing conditions
affect water requirements for
high wind or temp = more water
disease = more water
seedling development = less water
crop maturity = less water
nitrogen encourages water use
What is climate?
the amount of water throughout the season
How is water measured for
Acre-feet = one acre (43,560 ft)
one foot deep
Barrel = 42 gallons
What is Flow?
given amount of water in a specific time
GPM, CFS, CFM, Barrels/day
apply 8" water
pump delivers 900 GPM
how long do you need to run the pump to get 8"
100 acres x .66' = 66 acre feet
(66 * 43,560) =2,874,960 CF
2,874,960 * 7.48 =
21,504,700 / 900 = 23,894 min or
16.5 days at 24 hrs/day
What are the types of irrigation?
Wild Flooding- hay
Furrow Irrigation - sugar beets
Subsurface Irrigation - water from
Sprinkler - center pivot, line, wheel line
Drip or Trickle - water applied directly to plant
What is moisture stress?
plants do not get enough water
How do plants deal with moisture
1) tolerate - do not grow as tall
2) escape - shorten life cycle
3) avoid - store water, roll up
How can we reduce moisture
reduce weeds (competition)
less seed (competition)