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Got Water? Developed by: Hud Minshew, Oregon State University Extension Service Susan Donaldson, University of Nevada Cooperative Extension UNCE, Reno, Nev. Today we’ll learn about Sources of irrigation water: surface versus well water Living n Matching available water to soils and plants Determining when it’s time to irrigate Irrigation systems the Land Where will you get your water? Do you have a water right? Living n Where will your water come from? When or how often will you get your water? the Land www.farmphoto.com So you think you’ll use your domestic well to irrigate a pasture? Living n Does local law allow use of domestic well water for pasture irrigation? Does your well produce enough water? UNCE, Reno, Nev. the Land Things to know before you start to irrigate What plants do you want to grow? Living n Do you have enough available water to support the plants? Are your soils appropriate for growing the plants you selected? the Land UNCE, Reno, Nev. More things to know before you start to irrigate Living n the Land Do you want to improve existing pasture, or start over? USDA Online Photos How much time and money do you have? Where do plants get their water from in the root zone? Adapted from PNW 475 by A. Miller Rooting Depth in Feet Alfalfa 4’ – 6+’ Plant rooting depths vary A. Miller Before you pick a crop, consider the soil What is the capability class of the soil? Living n What are the slopes and aspects? How deep is the soil? Does it have adequate drainage and rooting depths? Is compaction an issue? the Land USDA NRCS Composition of a loam soil Living n Mineral Fraction (sand, silt, clay) = 45 to 50% the Land Water = 20 to 30% Air = 20 to 30% Organic Matter = 0 to 5% Soil texture How does it feel in your hand? . NRCS, Bozeman, Mont. CLAY SILT Moderate spread and infiltration SAND Deepest penetration Wide, but more shallow, infiltration Water spreads differently in different soil textures Soil texture and drainage A. Miller Soil texture Sand Sandy loam Infiltration rate, inches per hour 2-4 1-3 Silt loam, loams 0.25 – 1.5 Silty clay loams, clay 0.1 – 0.3 0.4 Water Content (% volume) 0.35 Field Capacity 0.3 0.25 Available Water 0.2 0.15 Wilting Point 0.1 Unavailable Water 0.05 0 Sand Sandy Loam Loam Silt Loam Clay Loam Silty Clay Clay Finer Texture Available water OSU Extension Service Available water A. Miller The water available to you Does your water right supply enough water? Living n 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? the Land UNCE, Reno, Nev. When is it time to irrigate? Living n 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 Land The Look-and-feel Method USDA NRCS Look-and-feel method Living n 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. the Land USDA NRCS Look-and-feel method Sandy loam or fine sandy loam at 25 to 50% moisture Living n Irrigation is overdue. the Land Sandy loam or fine sandy loam at 50 to 75% moisture Will need to irrigate soon. Screwdriver method Living n the Land UNCE, Reno, Nev. Using evapotranspiration data to schedule irrigation Bureau of Reclamation Irrigation water quality Living n 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? the Land Saltaffected soils USDA-NRCS Irrigation methods: selecting the system that’s right for you Surface Sprinkle USDA NRCS Micro-irrigation Are you using an existing system, or starting over? Your flexibility may be limited with an existing system, but costs will be lower Living n 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 the Land What source of power will you use? None – select an irrigation system that does not require power Living n Electricity from an existing power line An internal combustion engine Solar power the Land Surface irrigation (gravity-flow) UNCE, Reno, Nev. NRCS Irrigation Page UNCE, Reno, Nev. Wild-flood irrigation Living n the Land UNCE, Reno, Nev. Contour-ditch irrigation Living n the Land Univ. of Virgin Islands Field leveling USDA NRCS Levelbasin irrigation USDA NRCS Corrugation UNCE, Reno, Nev. CSU Cooperative Extension Furrow irrigation (level and graded) Living n USDA NRCS the Land USDA NRCS Contour-furrow irrigation Living n the Land Icrisat.org Furrow irrigation with siphon tubes USDA NRCS USDA NRCS Components of a border irrigation system A. Miller USDA NRCS Gated pipe Living n UNCE, Reno, Nev. USDA ERS USDA NRCS the Land NRCS Irrigation Page Surge irrigation Living n Water delivery is controlled by a valve. the Land ERS USDA Alfalfa valves Living n the Land Univ. of Idaho Extension Bubbler screen Living n the Land B. Hamblen, CSU Extension Reducing return flows Living n the Land USDA NRCS OSU Extension Service Reusing tailwater Do you have a legal right to reuse tailwater? Living n How will you capture and store the water for subsequent use? Maximizes the use of surface irrigation water. the Land Ditch maintenance Dredging and redigging Weed and vegetation control Living n Opening and closing of gates Adjusting of siphon tubes Who will do it, and what will it cost? Permission and access issues the Land OSU Extension Service Powered systems: sprinklers UNCE, Reno, Nev. Center-pivot Living n the Land USDA NRCS Mini-pivot sprinklers Living n the Land USDA NRCS Mont. Low-energy precision-application sprinklers USDA NRCS USGS Traveling guns (big gun) www.clemson.edu Living n the Land USDA NRCS Traveling mini-guns USDA NRCS K-line® and Irripod® sprinklers Photo source? kygraziers.com www.k-linena.com Hand lines Living n ERS USDA the Land USDA NRCS Side roll wheel lines Living n the Land USDA NRCS USDA NRCS Solid-set sprinkler UNCE, Reno, Nev. Below-ground popups Living n the Land Univ. of Idaho Extension Drip irrigation Living n the Land Graphic by A Miller, adapted from USDA-SCS 1984 USDA SCS Drip irrigation USDA NRCS USDA ARS Subsurface drip irrigation Living n the Land UNCE, Reno, Nev. Activity Living n Create a table showing the pros and cons of each of the irrigation systems discussed. the Land Living n Checking your system: Does it apply water uniformly? the Land UNCE, Reno, Nev. Improving uniformity Monitor your system during irrigation and check for leaks or clogging of screens Living n 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 Land The can method for measuring uniformity – a low-cost approach OSU Extension Service Irrigation systems summary Know your sources of irrigation water Living n Know your soil type Monitor soil moisture Improve efficiency of your delivery system when possible the Land Irrigation systems summary Adjust rate of water application to avoid runoff Living n Know your labor availability Match your goals for your land to the irrigation system you select the Land Homework Practice the Look-and-feel Method for determining irrigation. Living n 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. the Land