Published on January 7, 2008
Generally Accepted Agricultural and Management Practicesfor Irrigation Water Use: Generally Accepted Agricultural and Management Practices for Irrigation Water Use Task Force Chair - Ted L. Loudon Note to Presenters: Handout material for this presentation is “ Irrigation Water Use GAAMP” Available from MDA at http://www.michigan.gov/mda/1,1607,7-125-1567_1599_1605---,00.html MSU Extension Educators Dr.Ted Loudon, Lyndon Kelley, Steve Siegelin, or other Irrigation GAAMPs taskforce members may be able to answer questions or present this material if needed. Generally Accepted Agricultural and Management Practicesfor Irrigation Water Use: Generally Accepted Agricultural and Management Practices for Irrigation Water Use Task Force Chair Ted L. Loudon Irrigation GAAMP Task Force: Irrigation GAAMP Task Force Climatology Jeff Andresen Environmental Interests Tom Cary, WMEAC Farm Bureau Scott Piggott Fruit Growers Don Gregory Great Lakes and WRC Fred Henningsen Groundwater Stewardship Lyndon Kelley Groundwater Hydrology David Lusch MDA Mike Gregg MDEQ Ron Van Til Irrigation GAAMP Task Force: Irrigation GAAMP Task Force Nursery Interests Amy Frankmann MSUE Field staff Don Smucker Mud Creek Irr. District Dean Smith NRCS John Barclay Potato Industry Comm. Ben Kudwa SW MI Seed Growers Ben Russell Turfgrass Interests Greg Lyman USGS Jim Nicholas Vegetable Growers Ron Goldy GAAMP Document in Three Sections: GAAMP Document in Three Sections I. Introduction Stewardship DO NOT ESTABLISH LEGAL CRITERIA to resolve water use conflicts DO NOT CONFER PRIORITY RIGHTS to water use II. The 25 GAAMPS System management (#1 – 7) Record keeping (#8 – 13) Irrigation scheduling (#14 – 19) Application practices (20 – 24) Other reasons to irrigate (#25) GAAMP Document in Three Sections: GAAMP Document in Three Sections III Background – Information and education Irrigation in Michigan Relation to other GAAMPS Michigan Water Law related to Irrigation Planning and Preparation for Irrigation Introduction – Stewardship: Introduction – Stewardship Stewardship of the water resource quantity Irrigators are to use water as efficiently as possible while providing the crop/landscape water needs Avoid over irrigation Stewardship of the water quality Irrigation without deep percolation or runoff Stewardship of the soil Use management practices to maintain the soil infiltration characteristics and increase organic matter content to increase water holding capacity Stewardship of the crop – sustain plant development Stewardship of the Agricultural sector of the economy Management GAAMPS: Management GAAMPS 1. Determine water applications accurately Totalizing flow meter and known area of coverage Calibrated sprinkler package and system speed Numerous rain gages in the field 2. Monitor pumping plant efficiency Maintain the desired flow and pressure Monitor system pressure System flow is uniquely related to system pressure Management GAAMPS (con”t): Management GAAMPS (con”t) 3. Evaluate the irrigation system uniformity To know what it is applying and how uniformly Periodically – every few (5-8) years or when something is changed Evaluate according to a standard NRCS handbook – Pivot run with catch cans spaced 15-30 ft. ASAE standards (436.1) – Pivot run with cans spaced 10 – 17 ft (3-5 m) Management GAAMPS (con’t): Management GAAMPS (con’t) 4. Maintain the irrigation system in good condition Mostly means have a detailed look at the machine Sprinklers rotating properly, nozzles not worn or blown out Proper pressures at the nozzles Pipes free from leaks Inspect regularly and document inspections Beginning of irrigation season During the season Management GAAMPS (con”t): Management GAAMPS (con”t) 5. Operate to minimize drift and off target applications Don’t water the roads or the neighbor’s house Avoid operation in high winds where possible Be sure stops and auto-switches are working properly 6. Insure that sprinkler nozzle packages are matched to the infiltration rate of soil Goal is to avoid runoff or run-on An initial design issue Runoff can sometimes be managed by reducing application amount or changes tillage practices In nursery systems, manage runoff by recycling or proper disposal Management GAAMPS (con”t): Management GAAMPS (con”t) 7. Provide noise control Internal Combustion engines running pumping plants or generators Mufflers Sound baffles Carefully chosen location Record Keeping: Record Keeping 8. Crop type and location 9. Source(s) of water used 10. Date and amount of each irrigation 11. Records on system inspections and repairs that influence uniformity and leaks 12. Calibration of fertigation and chemigation equipment, if used 13. Records on system uniformity evaluation Irrigation Scheduling: Irrigation Scheduling Scheduling is determining when to irrigate and how much water to apply Everyone schedules!! Scientific methods involve treating the soil as a reservoir for plant water and maintaining the reservoir within an acceptable range for plant use Irrigation Scheduling: Irrigation Scheduling 14. Know the available soil water holding capacity (AWC) for each unit scheduled AWC is the difference between the soil water content at the drained upper limit (“Field Capacity”) and the content at which plants permanently wilt. Data available from NRCS Usual range is .07 -- .15 inches of water per inch of soil or 0.8 – 1.8 inches per foot. Irrigation Scheduling: Irrigation Scheduling 15. Know the depth of rooting for each crop irrigated 16. Use container capacity for scheduling for container grown nursery crops Typical container substrate capacity ranges 45 – 60% by volume 17. Know the allowable depletion of each crop and stage of growth The allowable water depletion is less than the total available water – usually 40 – 60% of total, depending on the crop and stage of growth Container depletion may be 25 – 35% of container volume Irrigation Scheduling: Irrigation Scheduling 18. Measure, estimate, or use published evapotranspiration data to determine crop water use Most often use indirect measure or estimate Measure soil moisture status Estimate using weather data Use published information (off the web) Even with good estimates, field checks are needed Irrigation Scheduling: Irrigation Scheduling 19. Measure rainfall in the field Application Practices(to avoid leaching): Application Practices (to avoid leaching) 20. Choose irrigation amounts that will avoid surface runoff Depends on soil type and system application rate Runoff and run-on can cause nonuniform application and leaching In container culture, manage runoff that may occur 21. Assure that sprinkler application rates are below infiltration rate of the soil Application Practices: Application Practices 22. Split applications of nitrogen fertilizer Goal is to avoid excess nitrogen leaching Rainfall right after irrigation can cause over filling of the soil water holding capacity and deep percolation which may leach excess nitrogen in the profile 23. Use appropriate backflow prevention devices if chemigation is used. 24. Avoid applying irrigation water in excess of that needed to replace the moisture deficit created by the crop depletion. Other Reasons to Irrigate: Other Reasons to Irrigate 25. Other needs for irrigation Frost protection Seed germination Herbicide activation Reduce disease Establishment of post-harvest cover crops Control of wind erosion in small and emerging crops Post-harvest maintenance of ornamentals Provision of proper conditions for harvesting (root) crops Chemigation Crop cooling in special cases with fruit crops Establishment and maintenance of a water table for sub-irrigation Background Section: Background Section This section is information and education, not accepted agricultural and management practices Divisions within the section Irrigation in Michigan Relation to other GAAMPS Michigan Water Law related to Irrigation Planning and Preparation for Irrigation Irrigation in Michigan: Irrigation in Michigan Importance of Irrigation nationally and in Michigan – used with higher value crops Goal of irrigation is to minimize moisture stress and maximize crop quality while minimizing the effect on the environment and water resources Michigan is water rich, but is the driest state east of the Mississippi during July and August Water is available to replenish aquifers and supply rivers and lakes during other parts of the year The GAAMPS do not establish legal criteria to resolve water use conflicts or confer priority rights to water use Irrigation in Michigan (con’t): Irrigation in Michigan (con’t) Irrigation replaces water used by plants Plants use water primarily for cooling Certain high value crops would not be grown in Michigan without irrigation High value crops provide added income in communities Access to irrigation water is key to high value crop production and the ripple effect on the economy Relation to Other GAAMPS: Relation to Other GAAMPS Manure Management GAAMPS recognize irrigation as a method of land application Nutrient Management GAAMPS recommends Don’t irrigate to completely fill the soil reservoir Use multiple applications of N-fertilizer Recognizes fertigation offers special advantages Special care when irrigating container grown plants to avoid leaching and runoff Pesticide Utilization GAAMPS Recognizes chemigation as an accepted practice Recommends safety measures including backflow prevention devices Water Law and Ag Water Use: Water Law and Ag Water Use Points out that P.A.83 of 1981 (the Right to Farm Act) provides farmers who follow GAAMPS with limited protection from nuisance suites. Adherence to the Water Use GAAMPS does not provide a complete barrier against lawsuits. Recommends that water users who are concerned about their rights, consult MSUE, NRCS, MDA, MDEQ, or an attorney versed in water law Planning and Preparation for Irrigation: Planning and Preparation for Irrigation Water Supply Plan to keep up with a water use of 0.25 in/day (approximately 5 gpm per acre) Some streams, lakes and wetlands may be sensitive to large withdrawals Groundwater removed for irrigation may reduce flow to these surface water bodies Planning and Preparation for Irrigation: Planning and Preparation for Irrigation Aquifer monitoring Seek information before drilling to determine adequacy of the source In areas where there is known potential for impacting other wells, consider using monitoring wells Drill and pump a test well before installing a production well Monitor levels in your irrigation well To determine the effect on the aquifer To determine need for maintenance Irrigation wells should be set up for monitoring the water level Recommend three measurements per year Before the irrigation season In mid-season, both static and dynamic levels After the end of the season Keep records on these measurements Questions and Discussion?: Questions and Discussion?
Generally Accepted Agricultural and Management ... 12 GAAMP Document in Three ... and Management Practices for Irrigation Author: Theodore Loudon