Developed by: Hud Minshew, Oregon State University Extension Service Susan Donaldson, University of Nevada Cooperative Extension UNCE, Reno, Nev.

 Sources of irrigation water: ◦ surface versus well water  Matching available water to: ◦ soils and plants  Determining when it’s time to irrigate  Irrigation systems

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

 Does local law allow use of domestic well water for pasture irrigation?  Does your well produce enough water? UNCE, Reno, Nev.

 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.

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

Adapted from PNW 475 by A. Miller

A. Miller Alfalfa 4’ – 6+’ Rooting Depth in Feet

 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

Water spreads differently in different soil textures Deepest penetration Moderate spread and infiltration Wide, but more shallow, infiltration    CLAY SILT SAND

Soil texture Infiltration rate, inches per hour Sand2 - 4 Sandy loam1 - 3 Silt loam, loams0.25 – 1.5 Silty clay loams, clay0.1 – 0.3 A. Miller

OSU Extension Service

A. Miller

 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.

 Rule of thumb: ◦ When the amount of water-holding capacity is at 50%  If your plants are showing signs of stress, irrigation is overdue ◦ Look for wilting or grasses that don’t spring back up when stepped on

The Look-and-feel Method USDA NRCS

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

Look-and-feel method Sandy loam or fine sandy loam at 50 to 75% moisture Sandy loam or fine sandy loam at 25 to 50% moisture Irrigation is overdue.Will need to irrigate soon.

UNCE, Reno, Nev.

Bureau of Reclamation COAgMet - local weather station info and daily ET rates. A great resource to know when to irrigate based on weather and EC

 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?

USDA-NRCS

Micro-irrigation Surface Sprinkle USDA NRCS

 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

 None – select an irrigation system that does not require power  Electricity from an existing power line  An internal combustion engine  Solar power ◦ This one pictured is not able to support a pressurized irrigation system. Can handle a stock tank though! USDA NRCS

NRCS Irrigation Page UNCE, Reno, Nev.

USDA NRCS

UNCE, Reno, Nev. CSU Cooperative Extension

USDA NRCS

A. Miller

Gated pipe USDA NRCS UNCE, Reno, Nev. USDA ERS

Surge irrigation ERS USDA Water delivery is controlled by a valve.

Alfalfa valves Univ. of Idaho Extension

B. Hamblen, CSU Extension

Reducing return flows

 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.

Who will do it, and what will it cost?  Dredging and re-digging  Weed and vegetation control  Open/close gates  Adjusting siphon tubes  Permission and access issues OSU Extension Service

Powered systems: sprinklers UNCE, Reno, Nev.

Center-pivot USDA NRCS

USDA NRCS Mont.

Low-energy precision-application sprinklers USDA NRCS USGS

Traveling guns (big gun) USDA NRCS

Traveling mini-guns USDA NRCS

K-line® and Irripod® sprinklers K-line® and Irripod® sprinklers

Hand lines ERS USDA USDA NRCS

Side roll/wheel lines USDA NRCS

Solid-set sprinkler UNCE, Reno, Nev.

Univ. of Idaho Extension

USDA SCS

Drip irrigation USDA ARS USDA NRCS

UNCE, Reno, Nev.

Checking your system: Does it apply water uniformly? UNCE, Reno, Nev.

 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

OSU Extension Service

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

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

 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.