Got Water?

1
Got Water?
Developed by Hud Minshew, Oregon State
University Extension Service Susan Donaldson,
University of Nevada Cooperative Extension
UNCE, Reno, Nev.
2
Today well learn about

• Sources of irrigation water surface versus well
  water
• Matching available water to soils and plants
• Determining when its time to irrigate
• Irrigation systems

3
Where will you get your water?

• Do you have a water right?
• Where will your water come from?
• When or how often will you get your water?

www.farmphoto.com
4
So you think youll use your domestic well to
irrigate a pasture?

• Does local law allow use of domestic well water
  for pasture irrigation?
• Does your well produce enough water?

UNCE, Reno, Nev.
5
Things to know before you start to irrigate

• What plants do you want to grow?
• Do you have enough available water to support the
  plants?
• Are your soils appropriate for growing the plants
  you selected?

UNCE, Reno, Nev.
6
More things to know before you start to irrigate

• Do you want to improve existing pasture, or start
  over?
• How much time and money do you have?

USDA Online Photos
7
Where do plants get their water from in the root
zone?
Adapted from PNW 475 by A. Miller
8
Plant rooting depths vary
A. Miller
9
Before you pick a crop, consider the soil

• What is the capability class of the soil?
• What are the slopes and aspects?
• How deep is the soil?
• Does it have adequate drainage and rooting
  depths?
• Is compaction an issue?

USDA NRCS
10
Composition of a loam soil
11
Soil texture
12
Water spreads differently in different soil
textures
13
Soil texture and drainage
A. Miller
Soil texture Infiltration rate, inches per hour
Sand 2 - 4
Sandy loam 1 - 3
Silt loam, loams 0.25 1.5
Silty clay loams, clay 0.1 0.3
14
Available water
OSU Extension Service
15
Available water
A. Miller
16
The water available to you

• Does your water right supply enough water?
• Will you have water during dry years?
• Do you need to reduce your irrigated acreage to
  match your water supply?
• Can you use your water more efficiently?

UNCE, Reno, Nev.
17
When is it time to irrigate?

• Rule of thumb when the amount of water-holding
  capacity is at 50 but thats hard to tell!
• If your plants are showing signs of stress,
  irrigation is overdue
• Look for wilting or grasses that dont spring
  back up when stepped on

18
The Look-and-feel Method
USDA NRCS
19
Look-and-feel method
Clay, clay loam or silty clay loam at 25 to 50
moisture
Clay, clay loam or silty clay loam at 50 to 75
moisture
Irrigation is overdue.
Will need to irrigate soon.
USDA NRCS
20
Look-and-feel method
21
Screwdriver method
UNCE, Reno, Nev.
22
Using evapotranspiration data to schedule
irrigation
Bureau of Reclamation
23
Irrigation water quality

• Does your irrigation water contain trace elements
  that may affect plant growth?
• Is the water salty?
• What are upstream users doing that might affect
  your water quality?

24
Salt-affected soils
USDA-NRCS
25
Irrigation methods selecting the system thats
right for you
Surface
Sprinkle
USDA NRCS
Micro-irrigation
26
Are you using an existing system, or starting
over?

• Your flexibility may be limited with an existing
  system, but costs will be lower
• Starting over allows you to carefully match
  soils, plants and water availability with
  irrigation systems, but can be costly
• New irrigation systems may save time, money or
  water

27
What source of power will you use?

• None select an irrigation system that does not
  require power
• Electricity from an existing power line
• An internal combustion engine
• Solar power

28
Surface irrigation (gravity-flow)
UNCE, Reno, Nev.
NRCS Irrigation Page
UNCE, Reno, Nev.
29
Wild-flood irrigation
UNCE, Reno, Nev.
30
Contour-ditch irrigation
Univ. of Virgin Islands
31
Field leveling
USDA NRCS

32
Level- basin irrigation
USDA NRCS
33
Corrugation
UNCE, Reno, Nev.
CSU Cooperative Extension
34
Furrow irrigation (level and graded)
USDA NRCS
USDA NRCS
35
Contour-furrow irrigation
Icrisat.org
36
Furrow irrigation with siphon tubes
USDA NRCS
USDA NRCS
37
Components of a border irrigation system
USDA NRCS
A. Miller
38
Gated pipe
UNCE, Reno, Nev.
USDA ERS
USDA NRCS
NRCS Irrigation Page
39
Surge irrigation
Water delivery is controlled by a valve.
ERS USDA
40
Alfalfa valves
Univ. of Idaho Extension
41
Bubbler screen
B. Hamblen, CSU Extension
42
Reducing return flows
USDA NRCS
OSU Extension Service
43
Reusing tailwater

• Do you have a legal right to reuse tailwater?
• How will you capture and store the water for
  subsequent use?
• Maximizes the use of surface irrigation water.

44
Ditch maintenance

• Dredging and redigging
• Weed and vegetation control
• Opening and closing of gates
• Adjusting of siphon tubes
• Who will do it, and what will it cost?
• Permission and access issues

OSU Extension Service
45
Powered systems sprinklers
UNCE, Reno, Nev.
46
Center-pivot
USDA NRCS
47
Mini-pivot sprinklers
USDA NRCS Mont.
48
Low-energy precision-applicationsprinklers
USDA NRCS
USGS
49
Traveling guns (big gun)
www.clemson.edu
USDA NRCS
50
Traveling mini-guns
USDA NRCS
51
K-line and Irripod sprinklers
Photo source?
kygraziers.com
www.k-linena.com
52
Hand lines
ERS USDA
USDA NRCS
53
Side roll wheel lines
USDA NRCS
USDA NRCS
54
Solid-set sprinkler
UNCE, Reno, Nev.
55
Below-ground popups
Univ. of Idaho Extension
56
Drip irrigation
Graphic by A Miller, adapted from USDA-SCS 1984
USDA SCS
57
Drip irrigation
USDA NRCS
USDA ARS
58
Subsurface drip irrigation
UNCE, Reno, Nev.
59
Activity

• Create a table showing the pros and cons of each
  of the irrigation systems discussed.

60
Checking your systemDoes it apply water
uniformly?
UNCE, Reno, Nev.
61
Improving uniformity

• Monitor your system during irrigation and check
  for leaks or clogging of screens
• Look for areas that remain too wet or too dry and
  adjust your irrigation system
• Check sprinkler system pressures and nozzles to
  make sure they are adequate
• Consider system upgrades

62
The can method for measuring uniformity a
low-cost approach
OSU Extension Service
63
Irrigation systems summary

• Know your sources of irrigation water
• Know your soil type
• Monitor soil moisture
• Improve efficiency of your delivery system when
  possible

64
Irrigation systems summary

• Adjust rate of water application to avoid runoff
• Know your labor availability
• Match your goals for your land to the irrigation
  system you select

65
Homework

• Practice the Look-and-feel Method for determining
  irrigation.
• Inventory your irrigation system, both existing
  and proposed, using the Irrigation Checklist for
  Landowners Activity Sheet.
• Check the uniformity of your sprinkler system,
  using any of the methods discussed in this
  lesson.