Transcript Irrigation

Irrigation
Chapter #7
What is irrigation?
the controlled application of water
 xerophytes, mesophytes,
hydrophytes

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
water used
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)

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

What is climate?

the amount of water throughout the season
What is the climate in Northeast
Montana?

semi-arid = 10-20" moisture/year
How is water measured for
irrigation?
Gallon
 Acre-feet = one acre (43,560 ft)
one foot deep
 Barrel = 42 gallons
 Cubic Feet

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?

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
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
What is moisture stress?

plants do not get enough water
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

How can we reduce moisture
stress?
reduce weeds (competition)
 less seed (competition)
 balance fertilizer
