Drip Irrigation For Mid-America Mark Burgess, C.I.D. Mark Burgess - 15 years with the USDA NRSCS, 9 years with Rain Bird as District Manager, and 5 years with Roberts Irrigation Products as District Sales Manager Certified Irrigation Designer for Ag Drip/Micro Regionally Authorized Instructor for the Irrigation Association This objective of this presentation is to give an overview of Sub-Surface Drip Irrigation, including things to be considered when making SDI decisions, system components, installation, maintenance, and information on 2 different farms. Bootheel Irrigation Conference December 15, 2003

Drip Irrigation A method of uniformly delivering water and nutrients to a plant’s root zone in the precise amounts in order to meet plant needs

Sub-Surface Drip Irrigation (SDI) A low pressure irrigation system that uses polyethylene driplines that are permanently buried below the soil surface, placing water directly into the root area of a crop.

Benefits of Drip Irrigation Crop yield and quality increase Improved field access during cultural operations such as cultivation, spraying, or harvesting Uniform delivery of water, chemicals and fertilizers Water usage reduced by irrigating only the root zone Lower pumping requirement and energy costs Less percolation of chemicals and fertilizers into the groundwater Controlled Wetted Area Reduced disease and weed growth Allows more saline water to be used for irrigation Irrigate small or irregularly shaped fields

Benefits of SDI Same as those of drip Reduced irrigation labor costs over Center Pivot (CP) Considered a permanent system

Things To Consider Water Availability Water Quality Crop Needs Field Conditions (soil, topography, dimensions, row configuration, and etc) Expectations (Lifetime of system, costs, uniformity, and etc.) Availability of technical assistance Maintenance Water Availability – Well or surface (pond or stream), and volume Water Quality - Test for use in drip irrigation system looking for minerals and other materials that may cause clogging problems. What are the irrigation requirements of the crop. Technical Assistance - Someone knowledgeable about drip irrigation, and specifically SDI so that a proper design is developed and questions can be readily answered. Maintenance - Plan ahead for the needed maintenance (flush capability, locations for checking pressures, flow meters, filter maintenance requirement, and etc.)

System Components 1. System controller (If automated) 2. Pump 3. Back flow prevention valve 4. Fertilizer injector/tank 5. Filter tanks 6. Butterfly valve or ball valve 7. Pressure gauges 8. Mainline control valve 9. Mainline 10. Flow meter 11. Air vents at high points, after valves and at ends of lines 12. Pressure relief valve 13. Field control valve 14. Submain secondary filters 15. Pre-set pressure regulator 16. Submain 17. Lateral hookups 18. Laterals 19. Flushing manifolds 20. Flush valves

Next Step Design Installation Flush system Take benchmark flow rates and pressures Design – Use someone who is experienced and qualified - design should include all pipe sizes, zone flow rates, system pumping requirement, filtration requirement, and specifications on pump and other components recommended. Install as designed, or if modifications are needed, they should be done with the approval of the person who has done the design so that the system will work properly. Make sure that all fittings and joints are properly glued and/or seated in order to prevent leaks. Flush system - This is extremely important and should be done as the system is installed (ie. Mains and submains followed by laterals and flushing manifold) Benchmark pressures and flow rates - should be taken for each zone in order to have base line information to confirm proper design and installation and for future reference so comparisons can be made to check how well system is performing over time. This information is very helpful in identifying possible problems before they become serious, such as clogging.

This is a system maintenance chart developed for use with drip systems which lists the recommended checks to be made during a growing season. This lists possible problems and causes based upon various checks (pressures and flow rates) that are made in each zone.

Common Problems Filtration Leaks Clogging

Filtration Filter Needs Cleaning Damaged Screen or Disc’s Flush Valves Not working Tank Failure Bad Gaskets and/or Seals

Leaks Broken Mains or Submains Damaged Laterals Loose Connections

Clogging Biological Chemical/Mineral Sand and/or Sediment Root Intrusion Maintenance Injection Biological – algae, bacteria, and etc Chemical/Mineral - caused by minerals in the water (ie. Iron and calcium) Maintenance Injection - where elements in the water react with fertilizers or chemicals injected during irrigation. Recommend using a jar test where a proportionate amount of the additive is put into the water and allowed to set overnight. If sediments appear, there is some type of incompatibility between the additive and what is in the water. Get help before injecting the material into the system.

Georgia Example GA – 7 year rotation corn/peanuts Row spacing – 32” Tape spacing – 64” Soil – Sandy clay Tape depth – 9” No till Tape – 15 mil 12 in. outlet Tape flow – 24 gph/100 ft Corn – 240 bu/ac Peanuts – 6,000- 6,500 lb/ac This is an example of SDI on a farm in south Georgia. The site has been irrigated using SDI for 7 years and is continuing to be in production. This grower found that a 9” depth worked very well throughout the crop, and especially for germination. This is a no-till field and the grower commented that it is extremely important for the crop rows to be in the same place from year to year on these soil types.

Kansas Example Crop - Corn Row spacing – 32” Tape spacing – 40” Soil – Loessial, silt, loam Tape depth – 16” – 18 ‘ Ridge Till, conventional Tape – 15 mil 12 in. outlet Tape flow – 15 gph/100 ft Corn – 210 bu/ac This information is based on a 10 year study done at Kansas State University and detailed information about this and other SDI studies are available on their web site.

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