Got Water?Got Water?

Developed by: Developed by: Hud Minshew, Oregon State University Extension ServiceHud Minshew, Oregon State University Extension Service

Susan Donaldson, University of Nevada Cooperative Susan Donaldson, University of Nevada Cooperative ExtensionExtension

UNCE, Reno, Nev.

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Today we’ll learn aboutToday we’ll learn about

Sources of irrigation water: surface versus well water

Matching available water to soils and plants

Determining when it’s time to irrigate

Irrigation systems

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Where will you get your Where will you get your water?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

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So you think you’ll use your So you think you’ll use your domestic well to irrigate a pasture?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.

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Things to know before Things to know before you start to irrigateyou 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.

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More things to know before More things to know before you start to irrigateyou start to irrigate

Do you want to improve existing pasture, or start over?

How much time and money do you have?USDA Online Photos

Where do plants get their water Where do plants get their water from in the root zone?from in the root zone?

Adapted from PNW 475 by A. Miller

Plant Plant rooting rooting depths depths

varyvary

A. Miller

Alfalfa4’ – 6+’

R

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ep

th in

Fe

et

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Before you pick a crop, Before you pick a crop, consider the soilconsider 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

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Water = 20 to 30%

Air = 20 to 30%

Mineral Fraction

(sand, silt,clay) = 45 to 50%

Organic Matter = 0 to 5%

Composition of a loam soilComposition of a loam soil

Soil Soil texturetexture

How does it feel in your hand?

NRCS, Bozeman, Mont..

Water Water spreads spreads differently differently in in different different soil soil texturestextures

Deepest penetration

Moderate spread and infiltration

Wide, but more shallow, infiltration

CLAY

SILT

SAND

Soil texture and drainageSoil texture and drainage

Soil textureInfiltration 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

A. Miller

Available waterAvailable water

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Sand SandyLoam

Loam SiltLoam

ClayLoam

SiltyClay

Clay

Finer Texture

Wa

ter

Co

nte

nt

(% v

olu

me

)

Available Water

Field Capacity

Wilting Point

Unavailable Water

OSU Extension Service

Available waterAvailable water

A. Miller

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The water available to youThe water available to youDoes 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.

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When is it time to irrigate?When is it time to irrigate?

Rule of thumb: when the amount of water-holding capacity is at 50% – but that’s hard to tell!

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 MethodThe Look-and-feel Method

USDA NRCS

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Look-and-feel methodLook-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

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Look-and-feel methodLook-and-feel methodSandy 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.

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Screwdriver methodScrewdriver method

UNCE, Reno, Nev.

Using evapotranspiration data Using evapotranspiration data to schedule irrigationto schedule irrigation

Bureau of Reclamation

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Irrigation water qualityIrrigation 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?

Salt-Salt-affected affected

soilssoils

USDA-NRCS

Irrigation methods: selecting the Irrigation methods: selecting the system that’s right for yousystem that’s right for you

Micro-irrigationMicro-irrigation

SurfaceSurface

SprinkleSprinkleUSDA NRCS

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Are you using an existing Are you using an existing system, or starting over?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

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What source of power What source of power will you use?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

Surface irrigation (gravity-flow)Surface irrigation (gravity-flow)

NRCS Irrigation Page

UNCE, Reno, Nev.

UNCE, Reno, Nev.

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Wild-flood irrigationWild-flood irrigation

UNCE, Reno, Nev.

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Contour-ditch irrigationContour-ditch irrigation

Univ. of Virgin Islands

Field levelingField leveling

USDA NRCS

Level- Level- basin basin

irrigationirrigation

USDA NRCS

CorrugationCorrugation

UNCE, Reno, Nev.

CSU Cooperative Extension

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Furrow irrigation Furrow irrigation (level and graded)(level and graded)

USDA NRCS

USDA NRCS

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Contour-furrow irrigationContour-furrow irrigation

Icrisat.org

Furrow irrigation with Furrow irrigation with siphon tubessiphon tubes

USDA NRCS

USDA NRCS

Components Components of a border of a border irrigation irrigation systemsystem

USDA NRCSA. Miller

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Gated pipeGated pipe

NRCS Irrigation Page

USDA NRCS

UNCE, Reno, Nev.

USDA ERS

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Surge irrigationSurge irrigation

ERS USDA

Water delivery is controlled by a valve.

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Alfalfa valvesAlfalfa valves

Univ. of Idaho Extension

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Bubbler screenBubbler screen

B. Hamblen, CSU Extension

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Reducing return flowsReducing return flows

OSU Extension Service

USDA NRCS

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Reusing tailwaterReusing 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.

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Ditch maintenanceDitch 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

Powered systems: Powered systems: sprinklerssprinklers

UNCE, Reno, Nev.

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Center-pivotCenter-pivot

USDA NRCS

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Mini-pivot sprinklersMini-pivot sprinklers

USDA NRCS Mont.

Low-energy precision-applicationLow-energy precision-applicationsprinklerssprinklers

USDA NRCS

USGS

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Traveling guns Traveling guns (big gun)(big gun)

USDA NRCS

www.clemson.edu

Traveling mini-gunsTraveling mini-guns

USDA NRCS

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

www.k-linena.com

kygraziers.com

Photo source?

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Hand linesHand lines

ERS USDA

USDA NRCS

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Side roll Side roll wheel lineswheel lines

USDA NRCS

USDA NRCS

Solid-set sprinklerSolid-set sprinkler

UNCE, Reno, Nev.

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Below-ground popupsBelow-ground popups

Univ. of Idaho Extension

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Drip irrigationDrip irrigation

USDA SCS

Graphic by A Miller, adapted from USDA-SCS 1984

Drip irrigationDrip irrigation

USDA ARS

USDA NRCS

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Subsurface drip irrigationSubsurface drip irrigation

UNCE, Reno, Nev.

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ActivityActivity

Create a table showing the pros and cons of each of the

irrigation systems discussed.

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Checking your system:Checking your system:Does it apply water uniformly?Does it apply water uniformly?

UNCE, Reno, Nev.

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Improving uniformityImproving uniformityMonitor 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

The can method for measuring The can method for measuring uniformity – a low-cost approachuniformity – a low-cost approach

OSU Extension Service

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Irrigation systems summaryIrrigation systems summary

Know your sources of irrigation water

Know your soil type

Monitor soil moisture

Improve efficiency of your delivery system when possible

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Irrigation systems summaryIrrigation 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

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HomeworkHomeworkPractice 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.