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Pecan Irrigation-and the irrigation system installation at the GCREC. Bryan Wilkins. Why Irrigate????. In South Alabama we generally get enough rain in June and July to size our pecans.
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Pecan Irrigation-and the irrigation system installation at the GCREC Bryan Wilkins
Why Irrigate???? • In South Alabama we generally get enough rain in June and July to size our pecans. • We don’t get enough steady rainfall during the critical August and September nut filling period to adequately fill the nuts out. • Irrigation can make up the difference.
Advantages of Drip Irrigation • Gives the best use of the available water supply by controlling the water flow to give maximum yields with the least amount of waste. • Evaporation loss minimal because the water it applied below the soil surface • Low pressure requirements=lower operating costs • Lower labor requirements • Irrigation can be applied anytime • Fertilizer can be injected through the system
Advantages of Drip Irrigation • Less disease and insect pressure • Less wetted area means less weeds and restricts populations of potential pest hosts No wind effect, lets you irrigate around the clock • It’s a permanent system • Easily and readily adapted to automatic controls • Provides improved infiltration in soils with low intake capacity • Allows for the use of more saline water.
Pecans and Water • Pecans have a very efficient water transport system • Developed ability to avoid stomatal closure under high temps with adequate water • Pecans are very inefficient users of water • Require large amounts of water to support optimal growth and fruit production
Disadvantages of Drip Irrigation • You must have a clean water supply. Adequate and dependable filtering systems are difficult to provide • Clogged emitters that result from poor water filtration, algae, bacteria, sulfur, iron and calcium in the water. • Non-uniformity of water discharged from the emitters. • On sandy soils water is not evenly distributed , the water does not tend to move laterally causing insufficient root volume wetting and leaching of nutrients. • Mice and rabbits and other animals cause damage by chewing on the flexible lines.
Other Advantages of Irrigation • Increased Nut Size/Quality, Nut Retention • Minimizes Shuck Decline/Sticktights • Enhances shuck split • Reduces Severity of alternate bearing • Ability to inject fertilizer and systemic insecticides
3,879 gallons 27trees/acre Extension Recommendation is 1 to 2 inches/week 1 acre inch x 27,154 gallons/acre inch x 7 days = 3,879 gallons/acre/year = 144 gallons/tree/day 2 acre inches = 288 gallons/tree/day
55 Acre Inches – Growing Season March 5” April 4” May 4” June 4” July 10” August 10” September 10” October 8” TOTAL 55”
Dormant Season Irrigation Water about every 6 weeks • Mid-November 2” • End December 2” • First February 2” TOTAL 6”
Water Source • 4” Well pumping 85 gallons/minute
Irrigation at GCREC • Installed August 2012 • Drip Irrigation components: • drip tube with ½ gph inline emitters spaced 3 feet apart • 2 lines per tree plowed in at the edge of the herbicide strip Cost of System: Parts and Labor: $700/Acre Well: 4 inch 5 HP $6200.00
Irrigation System Design • The system is a continuous loop, live feed system. • It has a 2” main feed line running through the center of the orchard. • 1½” lines on the end of the rows supplying water. • All drip lines are plugged connected to the main feed and the lines on the end of the row. • This creates a continuous water supply that keeps the pressure up and waters more effectively all the way down the row.
System Maintenance • A siphon valve is installed to put acid and chlorine through the system periodically • Acid will clean any mineral deposits that may block the emitters and chlorine will take care of algae and bacterial slime
Irrigation Experiment • 2 Treatments: Irrigated and non-irrigated • 5 Replications • 3 Tree plots with the center tree being the record tree • Non irrigated trees have the water shut off with ball valves
Irrigation Experiment • Data to be collected: • Date of shuck split • Harvest date • Percent of shuck tights • Percent Kernel • Total Yield