Operation of a Subsurface Drip Irrigation (SDI) system under National Organic Plan (NOP) Standards

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2010: $14,560.00
Projected End Date: 12/31/2012
Region: Western
State: New Mexico
Principal Investigator:
Minor Morgan
North Valley Organics

Annual Reports


  • Agronomic: corn, oats, rye, sorghum (milo), sunflower, grass (misc. perennial), hay
  • Fruits: melons
  • Vegetables: beans, beets, broccoli, cabbages, carrots, celery, cucurbits, eggplant, garlic, greens (leafy), onions, peas (culinary), peppers, tomatoes, brussel sprouts
  • Additional Plants: ornamentals


  • Animal Production: feed/forage
  • Crop Production: conservation tillage
  • Education and Training: demonstration, farmer to farmer, on-farm/ranch research
  • Farm Business Management: whole farm planning, farm-to-institution
  • Pest Management: biological control, cultural control, mulches - living, cultivation
  • Production Systems: organic agriculture
  • Soil Management: green manures, organic matter, soil analysis, nutrient mineralization, soil microbiology, soil chemistry, soil physics, soil quality/health
  • Sustainable Communities: local and regional food systems, urban agriculture, community services


    The primary purpose of this project was to demonstrate whether it is possible to operate a subsurface drip irrigation (SDI) system under organic standards and specific processes to stay within the National Organic Plan (NOP) standards. SDI offers many advantages over surface laid drip tape for growing crops but comes with one main disadvantage: keeping the tape emitters clear without using sulphuric acid, the industry norm for cleaning SDI systems. Sulphuric acid is a prohibited substance under NOP. Results of the two year project demonstrated that it is indeed possible to operate SDI under NOP standards, but special precautions need to be taken.

    Major lessons learned are: 1) SDI requires no/minimal tillage practices, 2) Tractor equipment equipped with GPS technology is critical, 3) A Zetacore catalytic water treatment system is essential, 4) A robust and well-designed filtration system is required, 5) Continual maintenance of the system is necessary, 6) Flushing the lines with each irrigation event is critical and 7) Periodic flushing of the drip line with hydrogen peroxide is critical.


    The subsurface drip irrigation system (SDI) began as an idea here in 2007 when Rio Grande Community Farm (RGCF) made a conscious decision to move into organic vegetable production in a much more intentional manner. RGCF is a non-profit farm “working on public land in the public interest.” We farm approximately 50 acres in a variety of crops and are located on a 140 acre plot owned by the City of Albuquerque. We have farmed the land as a non-profit since 1997. With the recession and after a reexamination of our Mission, the RGCF Board decided to focus on growing food crops for our citizens, particularly targeting vegetable crops for our school system, Albuquerque Public Schools (APS). Since 2008 RGCF has had a contract to sell vegetables to APS.

    At the same time, the City of Albuquerque applied to utilize an existing well on the property that had not been used for several years. The City had the water rights, but in order to perfect the rights it was required by the State Engineer to install “highest and best use” technology in utilizing the well water. This coincided with our application under the NRCS EQIP program to install a drip irrigation system on 16 acres. We appreciate the strong support given us by Josh Sherman and his staff in the Albuquerque USDA office for the EQIP grant which partially funded the installation of the SDI system. Josh suggested we install “subsurface drip” as it was considered the #1 technology regarding water use efficiency for vegetable crops.

    During the installation period from 2008-2010, I had blithely assumed there would be ample information available on the operation of a SDI system under organic certification. This turned out to be far from true - in fact there is almost no information available on organic operation of an SDI system. Realizing that what we would be doing would be of great interest to many farmers in the Southwest and across the nation, we applied for a USDA Conservation Innovation Grant (CIG) and a Western SARE grant. The CIG program in particular requires the integration of two or more existing proven technologies that have been proven effective in agriculture, but whose integration together has not been proven or well-documented. Western SARE targets farmers utilizing innovative technology to meet demonstrated regional challenges. Our use of SDI technology clearly met these criteria. Under the Western SARE grant we have operated under the mentorship and collaboration with the Bernalillo County Extension office which is part of our land grant university, New Mexico State University. Our mentor and Western SARE sponsor, Joran Viers, has been a tireless and always supportive partner in the rollout and implementation of the SDI irrigation system. Joran is the Bernalillo County Extension Director and has been a supporter of organic and sustainable farming for many years. We also appreciate the ongoing support of Norm Vigil and Seth Fiedler in the USDA New Mexico State office for the CIG grant. We could not have completed this project without the expert advice of Seth on navigating the myriad federal forms involved and Norm for ongoing support in the concept of organic SDI.

    A brief description of subsurface drip technology

    Simply stated, SDI is the use of plastic drip irrigation tape that is semi-permanently buried in the ground. Subsurface drip and above ground drip share many of the same challenges and vary in the overall system components only slightly. Both require pumps to pressurize the system and filters to clean the water. Both require valves, zone stations and pressure regulators to control the areas irrigated. Both involve extensive piping in the form of manifolds, flush valves and main lines to distribute the water. Both involve drip tape with emitters that release the water to the plants. For subsurface drip (SDI), the tape is buried in the ground anywhere from 6”-18” below grade, and the expectation is that it is not removed for several years. Surface tape is often rolled out every year. Occasionally it is re-used, but standard practice is often to throw it away and use new tape every year.

    For both surface and subsurface drip tape, a major challenge is to keep the emitters clear and water flowing out of the emitters. There are a number of reasons why emitters get clogged. In addition to the many benefits of burying the tape, the main challenge is how to keep the tape intact and damage free from a variety of four-legged and two-legged creatures. And herein lies one of the major conclusions of our study.

    As funny as it may sound, neither Dan our Chief Farmer, nor myself fully understood the implications of subsurface drip. It hit us one day full force after the system was installed and we were planning for crop production. Dan had literally hooked up the five ton double gang heavy discs and was preparing to disc the field. In one of those “ah-ha!” moments Dan and I looked at each other and exclaimed “Holy Cow! We can't do this anymore!”

    Subsurface drip requires you to engage in minimal/no till tillage operations to avoid cutting the lines. Our lines are buried 6” below the surface, and we have had to retool and rethink all our tillage practices. So here is a major conclusion: if you install subsurface drip, you will be engaged in no/minimal till tillage. Both Dan and myself are traditional farmers in that we have used shanks, discs, plows and other implements that greatly disturb the soil. But with the installation of the SDI, we were now instantly no till!

    Having realized that we were not only beginning to use new drip technology but also needed to retool all our operations, we went screaming to our USDA partners and Western SARE mentor Joran Viers: “What the heck do we do?!?” Well, we formed the Brain Trust. This is a group of several individuals that have met on a regular basis in 2010/2011 and intermittently since. Their brain power, and more importantly their emotional and psychological support, have been invaluable in overcoming the many challenges of operating an SDI system under organic certification, using no/minimal till methods. Members of the Brain Trust are:

    Joran Viers, Bernalillo County (NM) Extension Director
    Dean Schwebach, 4th generation farmer
    Tim Cavalier, Engineer and developer of the Zetacore water
    treatment system
    Lee Orear, retired Sandia National Laboratories hydrologist
    Rudy Garcia, USDA soil conservationist, NM State office,
    Clarence Chavez, USDA soil conservationist, NM State office,
    Walter Dodds- soil scientist and owner of Soilutions Organic
    Nick Penalosa, organic farmer
    Dan Schuster, Chief Farmer, RGCF
    Minor Morgan, Executive Director, RGCF

    This group met regularly and their feedback and collaborative spirit was truly inspiring. Without their sagacity - and sense of humor - we could not have made the transition to SDI no/minimal till.

    A hearty and deep felt thanks also goes out to the following folks for support:

    Deb Thrall of the Albert Pierce Foundation
    McCune Foundation
    Albuquerque Community Foundation
    Craig Maple, Brett Baker and Joanie Quinn of the NM Department of Agriculture
    Dr. Ron Gooden and Don Bustos on advice regarding no till
    The many vendors who donated time, expertise or materials to the project including Dusty Singh of Sierra Irrigation/Barron Supply, Franks Supply, Bern Maier of New Mexico State University, Keden Burk of EuroDrip USA, Mauro Herrera of NM office USDA, Brent McGill of Mueller, Inc.
    Parks and Recreation Department and the Open Space Division, City of Albuquerque

    We also visited or had discussions with the following farms using SDI:

    David, Carol and Howard Wuertz, Arizona Drip- “The Grandfather” of subsurface drip
    Todd Brendlin, Grimway Farms, California
    Chris Sichler, Sichler Farms, New Mexico
    Scott White, University of Arizona
    Steve Bassi, Tanamura and Antle Farm, California
    Dean Schwebach, Schwebach Farms, New Mexico

    We are grateful to these farmers for the information they shared and their pioneering spirit. We appreciate Howard Wuertz and son David in particular for the many hours they spent showing us their 5,000 acres in subsurface drip. Howard pioneered this technology in the 1970s and continues to this day to develop implements and processes for SDI and no/minimal tillage. We purchased our first no till implement - a “lister/peeler” from the Wuertz family during our visit in 2009. See Appendix A for information on Howard Wuertz and his farm.

    Project objectives:

    To document the procedures, processes and activities involved in operating a subsurface drip irrigation system, including extensive data collection.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.