Orchard Irrigation Joseph M. Hannan Commercial Horticulture Field Specialist Serving Central and Western IA Iowa State University Extension 28059 Fairground Rd. Adel IA jmhannan@iastate.edu 515.993.4281 office Topic Design & Operation of Irrigation Systems for Orchards Topic High flow rates Big zones Suppliers John Deere Water Jain Netafim Rainbird Toro Emitters Types Drip Low pressure spray Drip Low pressure Low volume Low energy requirement Small and large fields Water in root zone 1
Low Pressure Spray (LPS) Low Pressure Moderate volume Low energy Small and large fields Covers entire surface area Low Pressure Spray (LPS) Low Pressure Moderate volume Low energy Small and large fields Covers entire surface area System Build out Source Pump Filter Ground rod 2
Electrical Pattern Lightning Rod Pumps Centrifugal Turbine Submersible Filters Screen/mesh Disk Media 3
Filters Screen/mesh Disk Media Filters Screen/mesh Disk Media Air vents Drain Valve Water Placement Water the tree Water the soil Water Placement Water the tree 4
Drip Emitter Placement Tree Emitter Drip Wetting Pattern 24 to 36 wetting radius Drip Line Water Placement Water the soil Drip Tube 24 to 36 wetting width No 1 Ring to Rule Them All Volume Pressure Velocity Run time Planning the System Operating pressure Emitter spacing Flow rate 5
Pipe Sizing Maximum flow rate Pressure Line length High Density Orchards With a take on drought Soil Moisture Tools Tensiometer Watermark ½ of root zone Bottom of root zone Effective Rooting Depth of Fruit Crops Crop Effective rooting depth z Major portion of roots Irrigation depth y Strawberry 1 ft 90% in top 8 inches 6 inches Blueberry 1 ft > 90% in top 8 inches 6 inches Raspberry, blackberry, gooseberry, currants, Aronia Apple, grape, other tree fruit z Affected by soil texture & aeration. 2 ft 70% in top 8 inches 12-15 inches > 3 ft 50% in top 12 inches 24-30 inches y Targeting 75-80% of the roots. When Do I irrigate? At what tensiometer reading do I turn on the water? 6
When Do I irrigate? 240 210 Apple Fruit Growth At what tensiometer reading do I turn on the water? IT DEPENDS! Fresh Weight (grams) 180 150 120 90 60 Cell Division Shoot elongation Fruit bud initiation Cell Enlargement 30 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 Days Past Full Bloom Tensiometer Set Points (cbars) Soil Texture Sandy loam Field Capacity* 25% Depletion* 5-10 10-15 50% Depletion* Loams 10-15 20-30 70 80* Silt loams 15-20 25-35 Clay loams 25-40 40-50 Fresh Weight (grams) 240 210 180 150 120 90 60 30 Cell Division Shoot elongation Fruit bud initiation Apple Fruit Growth Cell Enlargement * No irrigation required * Of the AWC in effective root zone 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 Days Past Full Bloom Irrigation Bath Tub Approach Row Feet Wetting radius How long to run pump? Rooting depth (volume of water to apply) Length Soil Type Wetted radius Crop Wetted Volume 7
Wetted Radius 24 to 32 inch 16 to 18 inch 4 to 6 inch Wetted radius from emitter line source Available Soil Moisture (Field Capacity - Permanent Wilting %) Soil Texture Inches / foot* Sand 0.5 Loamy sand 1.0 Sandy loam 1.5 Loam 2.0 Silt loam 2.5 Clay loam 2.5 Clay 2.0 * Approximations, check your County Soil Survey. County Extension or NRCS office Math Time! Need to know Row feet Wetting radius Rooting depth Soil type Irrigation Tool Calculates gallons to apply Run times 27,000 gals / acre inch 43560 sq ft / acre Drought Recording Questions http://www.extension.iastate.edu/topic/recovering-disasters 8
Joseph M Hannan Commercial Horticulture Field Specialist Serving Central and Western IA Iowa State University Extension 28059 Fairground Rd. Adel IA jmhannan@iastate.edu 515.993.4281 office This project is funded in part by Iowa State University Iowa State University Extension the Leopold Center for Sustainable Agriculture 9