IRRIGATION MANAGEMENT CALIFORNIA ALMOND SUSTAINABILITY PROGRAM Acknowledgments Editors Daniel Sonke, D.P.M., Senior Scientist, SureHarvest Andrew Arnold, Senior Consultant, SureHarvest Gabriele Ludwig, Ph.D., Associate Director, Environmental Affairs, Almond Board of California Jeff Dlott, Ph.D., President, SureHarvest Contributing Reviewers Matt Angell, Strategic Farming, Inc. Walt Bentley, IPM Entomologist, UC Kearney Research and Extension Center Joe Browde, Ph.D., Professional Services Manager, SureHarvest Patrick Brown, Ph.D., Pomologist-AES Professor of Plant Nutrition, UC Davis Joe Connell, Farm Advisor, UC Cooperative Extension, Butte County Robert Curtis, Associate Director, Agricultural Affairs, Almond Board of California David Doll, Pomology Farm Advisor, UC Cooperative Extension, Merced County Roger Duncan, Pomology Farm Advisor, UC Cooperative Extension, Stanislaus County Dave Goorahoo, Ph.D., Assistant Professor - Vegetable Crops, CSU Fresno Stan Grant, Principal, Progressive Viticulture Christopher Hartley, Ph.D., District Conservationist, NRCS - Stanislaus County Tim Hartz, Ph.D., Vegetable Crops Specialist, UC Davis Brian Hockett, District Manager, Northwest Kern Resource Conservation District Will Horwath, Ph.D., Professor of Soil Biogeochemistry, UC Davis Parry Klassen, Executive Director, Coalition for Urban/Rural Environmental Stewardship Bruce Lampinen, Ph.D., Integrated Orchard Management/Walnut and Almond Specialist, UC Davis Rob Mikkelsen, Ph.D., Western Region Director, International Plant Nutrition Institute Ron Nydam, Waterford Irrigation Supply and President, California Agricultural Irrigation Association Terry Prichard, Irrigation Water Management Specialist, UC Cooperative Extension Blake Sanden, Irrigation/Soils Farm Advisor, UC Cooperative Extension, Kern County Ken Shackel, Ph.D., Professor of Pomology, UC Davis Jim Yager, Ph.D., Strategic Farming, Inc. 2 CALIFORNIA ALMOND SUSTAINABILITY PROGRAM—IRRIGATION MANAGEMENT INTRODUCTION – SUSTAINABILITY AND IRRIGATION MANAGEMENT The first almond orchards in California were primarily planted as done for centuries in Europe—on hillsides without irrigation. Almonds originate in dry areas of central and southwest Asia and are highly drought tolerant. However, as the industry grew in the first half of the 20th century, a revolution in California Almond farming took place when growers discovered that planting orchards in fertile, well-drained soils with irrigation and fertilization could double or triple yields. This innovation and the subsequent expansion of almond growing in the Central Valley eventually established California as the leading source of almonds globally. In the intervening years, a dramatic change has also taken place in irrigation technology. To early flood and furrow systems were added various sprinkler types and then drip tape and micro-sprinkler systems. Besides new systems for distributing the water in the orchard, new technologies have been developed to support decisions for optimizing the amount and timing of water applications—soil moisture sensors, tensiometers, evapotranspiration devices, and pressure chambers for measuring plant water stress. Some of these devices are now connected to the Internet and transmit data that can be checked via cell phone. Additional technologies are being researched; some will likely become commercially viable in the future. The introduction of advanced irrigation technologies over the past three decades led to another significant increase in yields for California Almond orchards, and this contributed to another major expansion period for the almond growing community. In addition to yield increases, the efficient timing and delivery of water can enable more efficient application of crop nutrients, reduce weed and disease pressures, and improve harvest timing. Of course, these technologies can require significant money and time to install and maintain, but they enable growers to maximize their return on water applied. Older technologies, such as flood or sprinkler systems, have some advan- tages for sustainability which should not be overlooked, however. For ex- ample, some older systems require less energy for pumping and therefore decrease adverse air quality impacts. Moreover, farmers who want to use vegetation or cover crops to build soil organic matter and/or keep dust down may need to deliver water to the entire orchard floor. It should also be pointed out that even older irrigation systems can be made more effi- cient by the use of best practices for scheduling and maintenance. Over time, various factors have reduced access to and/or increased the price of irrigation water in much of California. Whether you need to re- duce water use or simply want to maximize yields, irrigation efficiency is critical for maximizing your returns in farming California Almonds today. CALIFORNIA ALMOND SUSTAINABILITY PROGRAM—IRRIGATION MANAGEMENT 3 Orchard Establishment The orchard establishment interval is the best opportunity to address many soil and water issues through strategic soil amendments, rootstock selection, tree spacing, irrigation system design and other measures. It is also the time to take stock of the investment required to maximize the orchard’s potential. Collecting information and thinking strategically prevent mistakes which might reduce yields or result in costly annual inputs. A MAP IS WORTH A THOUSAND WORDS Since the first aerial photos of fields became available, people have been struck by how a simple photograph can reveal soil variations as variations in crop growth. Of course, not everyone can jump in a plane and take a photo of a field, but today satellite photos are downloadable for free from the Internet. Often, you can download several photos going back years or even decades. When establishing a new orchard, photographic records provide an opportunity to look at whatever was growing on the property before and see if there are areas of poor growth which might reflect soil variations or problems. This simple bit of information can help to target sampling for soil compaction, soil type, nematodes, etc. USDA soil maps are also freely available online and allow you to identify potential soil differences (e.g., sand streaks) which may impact the watering needs of trees in different parts of the orchard. These maps are not always highly accurate, so they should be used as a starting point for guiding soil testing. Sensing technologies, such as soil electroconductivity (EC) mapping, provide additional information. EC mapping technology maps variation in the soil related to soil texture or salinity—either of which may require attention prior to orchard development. Use the maps to guide sampling and additional testing. Few people have tried yield mapping in orchard crops, but yield maps are becoming more common in field crops. If the previous crop on this land was yield mapped, this information could be used to identify soil variations as well. 4 CALIFORNIA ALMOND SUSTAINABILITY PROGRAM—IRRIGATION MANAGEMENT N Thinking outside the o t U rectangle fa se m d N Fimopr rtohvisin ogr cwhaatredr, uthsee feoflfilocwieinncgy p wraecreti cuesse dan ddu/roinr gte ecshtnaoblloisghimese fnotr: iliar w I didn this p ot app Mrirerocigstaat ntpigorounpl aseer,r ttasyn p dlirn omebsoa asbtrl ey are ith this ’t try it ractice licable ausn iwfoerlml. F soori l,o arc rheacrtdasn gwuitlahr design may be best. However, 1 Were you involved in this orchard’s establishment? soil conditions can vary n Yes (continue with the following questions) across a block significantly. n No (skip to question 16 on page 12) To ensure optimal yields, 2 Soil maps (e.g., NRCS soil series or web soil survey) were used to associated irrigation identify potential variations in soil texture, salinity, water holding n n n rates ideally vary by soil capacity, or other factors. condition. So, rather than simply asking your irrigation 3 Aerial or satellite photos (e.g., Google Earth) were used to identify n n n system designer for the least potential variations in soil texture, salinity, or other factors. expensive installation, analyze 4 Yield maps from the previous crop (almonds or another crop) were options for creative ways used to identify potential variations in soil texture, salinity, or other n n n to improve your economic factors. returns through more 5 A GPS map of soil characteristics using sensing technology (e.g., EC, efficient water application Veris® or SIS) was made and used to identify potential variations in soil n n n —even if a more expensive texture, salinity, or other factors. system is needed. 6 Backhoe pits were dug or deep auger/core samples were taken One guide to getting the (guided by the above and other observed factors) in strategic places n n n best irrigation system for to determine: your money is the Irrigation a. texture (percent sand, clay, silt) or saturation percentage n n n Consumer Bill of RightsTM from the Cal Poly Irrigation b. compaction layers or other soil stratification n n n Training and Research Center. c. salinity n n n A copy is provided in this module. d. pH n n n e. soil organic matter n n n 7 Deep ripping, slip plowing, or tree hole backhoe pits were dug to address drainage and/or compaction issues (preferably after first n n n n testing for these problems). 8 If suggested by soil sampling, soils were amended to adjust pH, n n n n sodicity, salinity, etc. during orchard development. 9 Soils were amended with organic matter during orchard development. n n n This practice may also have food 10 All water sources were sampled and lab-evaluated for water quality/ n n n safety implications. Consult ABC irrigation suitability. GAP recommendations for more information. 11 Rootstocks were selected based on soil texture and drainage n n n conditions as well as potential soil pest or disease problems. 12 The irrigation system was designed to meet or exceed a specific target n n n distribution uniformity. 13 The irrigation system was designed for the site so that irrigation sets n n n correspond to soil texture zones and/or topography. 14 An economic analysis utilizing the type of information in this section and expected returns was done prior to moving forward with the n n n n orchard development/redevelopment. 15 Other: ____________________________________________________ n CALIFORNIA ALMOND SUSTAINABILITY PROGRAM—IRRIGATION MANAGEMENT 5 References and more information Boswell, Michael J. 2000. Toro Ag Irrigation Micro-Irrigation Design Manual. Toro Ag Irrigation, El Cajon, CA. Hanson, Blaine, Larry Schwankl, and Alan Fulton. 1999. Scheduling Irrigations: When and How Much Water to Apply. University of California Irrigation Program, University of California, Davis. Irrigation Training and Research Center, California Polytechnic State University. 2001. General Irrigation Consumer Bill of RightsTM. ITRC Publication 01-007. Lund, Eric D., Colin D. Christy, and Paul E. Drummond. 2000. Using Yield and Soil Electrical Conductivity (EC) Maps to Derive Crop Production Performance Information. 5th International Conference on Precision Agriculture 2000. Micke, Warren C., ed. 1996. Almond Production Manual, Publication 3364. University of California Division of Agriculture and Natural Resources, Oakland, CA. Netafim USA. 2009. Drip Irrigation Operation and Maintenance. Netafim, Fresno, CA. NRCS Web Soil Survey: http://websoilsurvey.nrcs.usda.gov Sanden, Blake. 2006. Soil and Water Quality for Trees and Vines. Proceedings California Plant and Soil Conference 2006. University of California, Davis Agricultural & Resource Economics Cost Studies: http:// coststudies.ucdavis.edu/ 6 CALIFORNIA ALMOND SUSTAINABILITY PROGRAM—IRRIGATION MANAGEMENT General Irrigation Consumer Bill of Rights Note: This supplements other DESIGNER QUALIFICATIONS Irrigation Consumer BillsTM • What are the dealer credentials (formal training, references, designer written for specific irrigation certification by The Irrigation Association, contractor’s license, and/or methods. Discuss these items with your irrigation professional agricultural engineer registration)? dealer before purchasing your irrigation system. The DESIGN FEATURES (GENERAL) discussion will help you • What is the life expectancy of system components? to make wiser selections • What safety features have been included? of design options, and to appreciate the obligations of • What are the options for future upgrades? both yourself and the dealer • What is the recommended list of spare parts? in creating your irrigation system. SPECIFIC OPERATING/DESIGN PARAMETERS • What will be the distribution uniformity on the whole field when brand new? • Does the system provide climate control? WATER REQUIREMENTS • What are the peak daily needs (acre-inches) for a normal year? • What is the system delivery capacity in 24 hours (acre-inches)? • What is the anticipated amount of water to be used per year (acre-feet)? • If the field has plants with different spacing, ages, or varieties, what is the recommended procedure to provide the appropriate amount of water per acre per week to each block? • Energy consumption: - Is it possible to pump all water during off-peak hours? - What are the pump and motor/engine efficiencies? - Are you provided with a pump curve showing the GPM and pressure? - What is the sensitivity of pump flow rates to well water changes? - What is the energy cost per acre-foot? • Filtration: - Is filtration necessary, and, if so, what type is provided? • Chemical injection: - Are locally required backflow prevention and safety devices provided? - What is the capacity of the injector in gallons per hour? - Can the equipment inject both fertilizers and other chemicals? • Flow meter: - Does it measure both flow rate (GMP) and volume (acre-feet) applied? - Does installation follow manufacturers’ recommendations with regard to lengths of straight pipe, pipe diameter, and straightening vanes? 8 CALIFORNIA ALMOND SUSTAINABILITY PROGRAM—IRRIGATION MANAGEMENT • Pressure, air, and flushing: - Are there adequate air vents, vacuum relief valves, and flush-outs? - What are the number, type, and size of pressure relief valves? - Is the pressure rating of all system components sufficiently high for the anticipated water temperature, surge pressures, and normal pressures? WARRANTIES • Who provides equipment installation, start-up, and adjustment? • What are the warranties on individual component and system design performance? • Who is providing warranties and what do the warranties cover and exclude? • Are the providers financially capable of standing behind their warranties? • What is the availability of replacement parts? • Will you be provided with a packet containing manufacturers’ literature, warranties, and operation instructions for the system? • Is the irrigation dealer a full-service dealer? The General Irrigation Consumer Bill of RightsTM and Irrigation Consumer Bill of RightsTM for Drip/Micro-irrigation were developed by the Irrigation Training and Research Center (ITRC) and reproduced here with ITRC permission. ITRC California Polytechnic State University (Cal Poly) San Luis Obispo, CA 93407 ph: 805.756.2434 fax: 805.756.2433 CALIFORNIA ALMOND SUSTAINABILITY PROGRAM—IRRIGATION MANAGEMENT 9 Irrigation Consumer Bill of Rights for Drop/Micro Irrigation Note: This supplements the FILTRATION General Irrigation Consumer • What is the equivalent mesh size? Bill of RightsTM. Discuss these • How frequently will filter flushing be necessary, and how much water items with your irrigation dealer before purchasing will be used per flush? How will the flush water be disposed of? your irrigation system. The • Does this filter require pre-filtration? discussion will help you • What is the procedure for flushing (manual, automatic, take-apart)? to make wiser selections • How is this filter protected from corrosion on both the inside and of design options, and to appreciate the obligations of outside? both yourself and the dealer • Does the pump provide enough water to flush the filter and operate the in creating your irrigation irrigation system simultaneously? Is a separate valve needed to sustain system. back flush pressure? • What are the initial adjustments necessary for the filter, and who will make them? • Through what variation in flow rate can the filter be effective? • Is a backup filter required? How will it be flushed, what are its mesh requirements, and where will it be located? • If a back flush flow adjustment is necessary, is it possible to view and sample the back flush water in order to make proper filter adjustments? • What is the safe operating pressure of the filter? • How much pressure loss is there through the filter when clean, and when dirty? FLOW RATES AND PRESSURES • What is the minimum pressure anticipated at any emitter? • What is the average emitter flow rate and pressure? • How are pressures regulated throughout the system? • Do pressure regulators require any adjustments? CHEMICAL INjECTION • What type of chemical injection is needed to minimize emitter plugging? • Has the water been tested for pH, iron, manganese, and sulfur bacteria problems? • What equipment components can be damaged by injected chemicals? GENERAL REDUCTION OF PLUGGING • Is insect damage to emitters a problem in the area? How will the design alleviate that problem? • Are adequate flush-outs provided throughout the whole system? • If used, can in-field filters and hose screen washers be easily cleaned? 10 CALIFORNIA ALMOND SUSTAINABILITY PROGRAM—IRRIGATION MANAGEMENT