The Organic Trade Association promised to look at the world of organic a little differently at its 2019 policy conference, and it kept its word.
The association invited other organizations that are working to advance food and farming priorities to share their bold ideas with the organic community. It hosted social influencers from around the country to educate them on the association’s work and the advocacy of its members. And it featured in-depth, no-holds-barred conversations on everything from how to make organic affordable for consumers and still profitable for farmers to the emerging hemp market and the opportunities it offers for organic.
The 250-plus attendees at the Organic Trade Association’s Bold Ideas + Critical Conversations conference on May 23 represented the diversity of today’s organic sector: organic grain and livestock farmers from Montana, organic fruit and vegetable growers from California and organic dairy producers from the Midwest, national organic brands and small organic businesses, organic certifiers and organic distributors, organic importers and organic exporters, and organic policymakers and organic trendsetters.
“This year’s conference was about new ideas and innovative thinking. Organic has come a long way, but we are dealing with some big challenges, and we are pleased that our conference enabled a frank discussion – and also some brainstorming – on how to keep organic advancing,” said Laura Batcha, CEO and Executive Director of the Organic Trade Association. “Now we need to make sure that this constructive conversation and positive action continue.”
Even the venue of the conference – Washington’s historic Union Market — represented organic’s embrace of the future and its respect for the past. Originating as Centre Market over 200 years ago, what is now today’s Union Market was at one time the city’s largest farmers’ market, with hundreds of vendors of produce, meat, eggs and everything in between. After surviving some turbulent times, it is now back on strong footing as a thriving revitalized economic growth center for the community that honors its culinary beginnings and also fosters a diverse culture of sights and sounds.
Collaboration and transparency
Making its debut at the conference was Coalition Alley. The Organic Trade Association assembled a broad coalition of partners to connect with the conference attendees about their diverse priorities. What did they have in common? All of the passionate advocates are doing important work to promote the best practices in farming, to educate the public about healthy food and lifestyle choices, and to create sound policy changes to advance agriculture.
Participants in Coalition Alley were American Farmland Trust, Organic Farming Research Foundation, National Farmers Union, National Sustainable Agriculture Coalition, National Association of State Departments of Agriculture, Partnership for a Healthier America, ShiftCon, USDA’s National Organic Program and The Organic Center.
Also marking a first at the annual conference was the Organic Trade Association’s first-ever Influencer Program. Seven widely followed social media influencers were chosen to cover the conference and other activities during Organic Week to get a behind-the-scenes look at organic advocacy in action.
The following of these enthusiastic and committed organic activists on Instagram alone totals some 263,000, but their reach and influence go far beyond that. Being able to experience directly the organic advocacy process in the nation’s capital, and to chronicle that experience to their hundreds of thousands of followers, was an invaluable learning lesson for all involved.
“Organic has nothing to hide,” said Batcha in kicking off the conference. “Organic is fighting for good, we wear the white hats, and we’ve turned back the curtain for the media on our lobbying efforts.”
“We all need to commit to dig in and improve the way the public/private partnership between the government and the organic sector works,” Batcha told attendees. “We need to keep organic advancing … All of agriculture can learn from organic, and everyone could benefit from organic moving forward.”
The impressive list of speakers and leaders at the conference included former Chief Agricultrual Trade Negotiator at the Office of U.S. Trade Representative Ambassador Darci Vetter; Rudy Arredondo, President and CEO of the National Latino Farmers and Ranchers Trade Association; Alice Rolls, President and CEO of Georgia Organics; Jeff Huckaby, President and CEO of Cal-Organic/Grimmway Farms; Gary Hirshberg, Co-founder of Stonyfield Farm; Carla Vernon, President of the Natural & Organic Operating Unit, General Mills; David Wasserman, U.S. House Editor and Senior Election Analayst, The Cook Political Report; Naomi Starkman, Founder and Editor-in-chief of Civil Eats, and many more.
Colombia and Panama are among the fastest-growing markets in the Western Hemisphere for U.S. farm and food products. American exporters seeking to tap that potential will join Under Secretary for Trade and Foreign Agricultural Affairs Ted McKinney in Bogotá for the U.S. Department of Agriculture’s largest-ever international trade mission June 4-7.
“The record size of this trade mission delegation demonstrates the degree of U.S. exporter interest in these markets,” McKinney said. “I’m thrilled that representatives from 54 agribusiness and associations and six state departments of agriculture are on board and ready to connect with potential customers from both Colombia and Panama.”
The United States entered into free trade agreements with both countries in 2012 and, since then, agricultural export growth has been robust.
“Our food and farm exports to Colombia have nearly tripled, from $1.1 billion in 2012 to a record $2.9 billion in 2018. And while Panama’s a much smaller market, we’ve also seen our exports grow significantly, from $490 million in 2012 to $683 million last year,” McKinney said.
In addition to representatives from the following companies and organizations, McKinney will be joined by Minnesota Commissioner of Agriculture Thom Petersen, Virginia Secretary of Agriculture and Forestry Bettina Ring, and officials from the Georgia, Idaho, Missouri and Montana departments of agriculture.
Agropur US, Appleton, Wis.
Alaska Seafood Marketing Institute, Juneau, Alaska
Alltech, Nicholasville, Ky.
American Paint Horse Association, Fort Worth, Texas
American Peanut Council, Alexandria, Va.
Blue Diamond Growers, Sacramento, Calif.
Bridgepathway LLC, Jericho, N.Y.
Clarkson Grain Company, Inc., Cerro Gordo, Ill.
Columbus Vegetable Oils, Des Plaines, Ill.
Cornerstone Chaldees LLC, Marion, Ky.
Crider Foods, Stillmore, Ga.
Crown Products, Inc. Metairie, La.
Eastern Quality Foods, Ponte Vedra Beach, Fla.
F3 Vineyards Inc., Las Vegas, Nev.
Federated Group, Arlington Heights, Ill.
Fieldstone Meats of Alabama, Inc., Oneonta, Ala.
Food Export Association of the Midwest USA, Chicago, Ill.
As California faces more frequent and severe droughts, agriculture, which relies on irrigation from surface water and groundwater, could become expensive and unsustainable. Researchers at the University of California, Davis, looked at using a “free” resource — rain water stored in the soil — and found that optimizing its use could go a long way to help meet demand for five California perennial crops. Their findings appear in the journal Environmental Research Letters.
“The study highlights a climate-smart opportunity to make better use of the rain that does fall,” said lead author Scott Devine, a postdoctoral researcher in the Department of Land, Air and Water Resources.
The study examined different water management scenarios for alfalfa, almonds, grapes, pistachios and walnuts. It found that water can be saved by delaying the first irrigation of the season to allow the crops’ roots to soak up more of the rainfall already stored in the soil. Devine said irrigating less frequently but more deeply also reduces water loss from evaporation, by allowing the soil surface to dry out.
In a 13-year irrigation management simulation based on climate data from 2003 to 2018, the study showed that these techniques could save enough water to fill California’s largest reservoir, Shasta Lake, more than six times.
Potential trade-offs
The magnitude of the water savings will vary depending on location, soil characteristics and climate. In some cases, irrigating less frequently could affect yield, and that yield loss needs to be considered relative to the value of water savings.
“This strategy may not work in some areas of the state where frequent irrigations are needed to keep salts from accumulating in the root zones,” said co-author Toby O’Geen, a professor and soil resource cooperative extension specialist in the Department of Land, Air, and Water Resources.
Researchers envision these strategies as a first step to managing limited water supplies in the future if droughts become longer and more frequent. O’Geen said exploring ways to encourage deeper roots for perennial crops is needed to efficiently capture more deep soil water storage.
The study was supported by funding from the National Science Foundation Climate Change, Water, and Society Integrated Graduate Education and Research Traineeship program.
Media contact(s)
Amy Quinton, News and Media Relations, 530-752-9843, cell 530-601-8077, amquinton@ucdavis.edu
Clean, transparent, fresh, sustainable. Environmentally friendly, animal humane, high quality, social activism. Those traits are all identified with organic, and in 2018 they all helped push organic sales to unprecedented levels. The U.S. organic market in 2018 broke through the $50 billion mark for the first time, with sales hitting a record $52.5 billion, up 6.3 percent from the previous year, according to the 2019 Organic Industry Survey released Friday by the Organic Trade Association.
New records were made in both the organic food market and the organic non-food market. Organic food sales reached $47.9 billion, for an increase of 5.9 percent. Sales of organic non-food products jumped by 10.6 percent to $4.6 billion. The growth rate for organic continued to easily outpace the general market: in 2018, total food sales in the U.S. edged up just 2.3 percent while total non-food sales rose 3.7 percent.
Millennials are pushing for transparency and integrity in the food supply chain, and they are savvy to misleading marketing. The USDA Organic seal is gaining new appeal as consumers realize that organic is a certification that is not only monitored and supported by official standards, but is the only seal that encompasses the spectrum of Non-GMO, no toxic pesticides or chemicals, dyes or preservatives.
Almost 6 percent (5.7 percent) of the food sold in this country is now organic. Today’s consumers can find organic products – food and non-food items — in every aisle of their grocery stores. They can choose organic in their favorite big box store, their club warehouse store, even in their neighborhood convenience store, and increasingly on the internet. Organic is no longer a niche market.
“Organic is now considered mainstream. But the attitudes surrounding organic are anything but status quo,” said Laura Batcha, CEO and Executive Director of the Organic Trade Association. “In 2018, there was a notable shift in the mindset of those working in organic toward collaboration and activism to move the needle on the role organic can play in sustainability and tackling environmental initiatives.”
“Activism is a natural reaction from an industry that is really close to the consumer. When we are in an environment where government is not moving fast enough, the industry is choosing to move to meet the consumer rather than get stalled,” said Batcha.
Produce still reigns supreme
Still the stalwart of the organic industry, sales of organic fruits and vegetables rose to $17.4 billion in 2018 for a 5.6 percent rate of growth, on par with the growth attained in 2017. By comparison, the overall fruits and vegetables category, including both organic and conventional products, grew by just 1.7 percent in 2018.
Fruits and vegetables now account for 36.3 percent of all organic food sales. Organic fruits and vegetable make up close to 15 percent (14.6 percent) of all the produce sold in the U.S., and have nearly doubled their market share in the last ten years.
Produce is a gateway to organic for consumers, especially Millennials and those with young families. Industry experts note that the more people learn about health and wellness, the more people buy fresh produce.
Popular in the organic produce aisles: the classics like carrots, greens, apples, bananas. Also hitting stride are organic berries, avocados, brussel sprouts, cauliflower and tropical fruits like mangoes and papayas. And outside the fresh produce section, the frozen, canned, and dried vegetable and fruit sections also made gains.
Innovation is key in the organic dairy market
Shoppers, especially young families, are increasingly seeking out products made from high-quality simple ingredients from brands committed to sustainable agriculture and its environmental benefits. Those shoppersturn to organic dairyas a trusted clean product free of antibiotics, synthetic hormones and chemicals. But growth in the U.S. dairy sector slowed for the second straight year due largely to shifting diet trends. Still the second-largest organic category, dairy and egg sales were $6.5 billion in 2018, up 0.8 percent from 2017.
Although growth in organic egg sales has slowed from the strong double-digit growth seen in the first part of this decade, the $858 million category still grew by a solid 9.3 percent in 2018. As more consumers get into organic, organic egg demand is expected to continue growing.
But where skim milk and low fat products were not so long ago favored by consumers, products high in healthy fats and protein are now popular. Many Millennials have also moved away from livestock-based products toward plant-based foods and beverages. Experts said that to satisfy today’s consumer, the importance of innovation in the organic dairy sector has never been greater. In 2018, the industry responded with milk beverages with increased protein, more full-fat dairy products, new flavors and grass-fed products.
Organic reaching far beyond food
Consumers are making the connection that the same reasons they choose to eat organic food apply to the non-food products they use–whether napkins for their dinner table, food for their pets, lotions they put on their skin or the supplements they ingest. Consumers want clean labels and to reduce the chemical load on their bodies. Millennials also have a higher awareness around supply chain transparency and sustainability. All of these factors bode well for the future of the organic non-food industry.
In 2018, the organic non-food category reached $4.6 billion in sales with a growth rate of 10.6 percent. This rate is both well above the 7.4 percent growth rate reported in 2017, and the 3.6 percent growth rate reported in 2018 for the overall non-food industry (conventional and organic combined).
The strongest growth came from fiber, the largest of the non-food categories, which accounts for 40 percent of the organic non-food market. In 2018, fiber recorded $1.8 billion in sales, up from $1.6 billion in 2017.
An organic outlook of innovation and activism
The outlook for organic is not without its challenges, but all expectations are that innovation and activism by the organic industry will continue to build as the sector works to maintain the credibility of the Organic seal and the trust of consumers.
“Organic is in a unique and tough environment. The government is slowing the advancement of the organic standard, but the positive news is that industry is finding ways to innovate and get closer to the consumer without walking away from the organic program—the sector is innovating yet requiring that federal organic be in place,” said Batcha. “So, whether it’s grass-fed, regenerative, or Global Organic Textile Standard certified, they all have to be organic. The industry is committed to standards and giving consumers what they want.”
This year’s survey was conducted from January through April 2019 and produced on behalf of the Organic Trade Association byNutrition Business Journal (NBJ). More than 200 companies completed a significant portion of the in-depth survey. Executive summaries of the survey are available to the media upon request. The full report can be purchased online.
WASHINGTON, May 7, 2019 — USDA’s Farm Service Agency (FSA) announced last week that the March 2019 income over feed cost margin was $8.85 per hundredweight (cwt.), triggering the third payment for dairy producers who purchase the appropriate level of coverage under the new Dairy Margin Coverage (DMC) program.
DMC, which replaces the Margin Protection Program for Dairy (MPP-Dairy), offers protection to dairy producers when the difference between the all milk price and the average feed cost (the margin) falls below a certain dollar amount selected by the producer.
“I encourage all dairy operations to sign up for DMC when we begin accepting applications in June,” said FSA Administrator Richard Fordyce. “Under certain coverage levels, the amount to be paid to dairy farmers for the months of January, February and March already exceed the cost of the premium.”
The signup period for DMC opens June 17, 2019. Dairy producers who elect a DMC coverage level between $9 and $9.50 would be eligible for a payment for January, February and March 2019.
For example, a dairy operation that chooses to enroll an established production history of 3 million pounds (30,000 cwt.) and elects the $9.50 coverage level on 95 percent of production would receive $1,543.75 for March
Sample calculation:
$9.50 – $8.85 margin = $0.65 difference
$0.65 x 95 percent of production x 2,500 cwt. (30,000 cwt./12) = $1,543.75
DMC premiums are paid annually. The calculated annual premium for coverage at $9.50 on 95 percent of a 3-million-pound production history for this example would be $4,275.
Sample calculation:
3,000,000 x 95 percent = 2,850,000/100 = 28,500 cwt. x 0.150 premium fee = $4,275
The dairy operation in the example calculation will pay $4,275 in total premium payments for all of 2019 and receive $8,170 in DMC payments for January, February and March combined. Additional payments will be made if calculated margins remain below the $9.50/cwt level.
All participants are also required to pay an annual $100 administrative fee in addition to any premium, and payments will be subject to a 6.2 percent reduction to account for federal sequestration.
Operations making a one-time election to participate in DMC through 2023 are eligible to receive a 25 percent discount on their premium for the existing margin coverage rates. For the example above, this would reduce the annual premium by $1,068.75.
About DMC
On December 20, 2018, President Trump signed into law the 2018 Farm Bill, which provides support, certainty and stability to our nation’s farmers, ranchers and land stewards by enhancing farm support programs, improving crop insurance, maintaining disaster programs and promoting and supporting voluntary conservation. FSA is committed to implementing these changes as quickly and effectively as possible, and today’s updates are part of meeting that goal.
For DMC signup, eligibility and related dairy program information, visit the DMC webpage or contact your local USDA service center. To locate your local FSA office, visit farmers.gov/service-locator.
USDA is an equal opportunity provider, employer and lender.
…Dairy Margin Coverage Program Sign-Up Begins June 17…
A new study shows access to international export markets for U.S. grains supported nearly $38 billion in business sales in the U.S. economy during 2016 beyond the value of the products themselves.
The analysis commissioned by the U.S. Grains Council (USGC) and the National Corn Growers Association (NCGA) found a total economic impact of U.S. grains exports of $55 billion that year, supporting 271,000 jobs directly or indirectly. These sales supported U.S. gross domestic product (GDP) by $19 billion over what would have occurred without such exports.
The analysis dives deep into the benefits to farmers, rural communities and the nation as a whole derived from overseas sales driven by strong trade policy and robust in-country market development for grains and grains products.
“Every sale counts for farmers, especially in this market, and this analysis shows just how much the grain sector is supported by regular and growing purchases from our overseas customers,” said Jim Stitzlein, the Council’s chairman. “These numbers out today take the analysis one step further to look at the whole economy, in our rural and farm communities but also in cities where people have jobs transporting, processing and shipping ag products.”
Informa Agribusiness Consulting conducted the study, which examined the economic contributions to each state and 52 congressional districts from exports of corn, barley, sorghum, ethanol, distiller’s dried grains with solubles (DDGS), corn gluten feed and meal as well as the corn equivalent of meat on the U.S. economy. The new study is an update to similar research done with 2014 and 2015 data, showing similar results.
Breaking down the numbers, these results showed every $1 of grain exports supported an additional $2.20 in business sales. Every job directly created by the export of grain and grain products supported an additional 3.9 jobs in the United States.
These indirect and induced business activities extend well beyond the agricultural industry, including the wholesale trade, real estate, oil and natural gas and service sectors.
“While corn growers can see first-hand the value our product provides to our local communities, this study demonstrates the positive economic impact we provide beyond our fields. Breaking the data down into individual states and Congressional districts will help us better inform legislators as we advocate for new market opportunities for U.S. corn,” said NCGA President Lynn Chrisp
The U.S. Grains Council develops export markets for U.S. barley, corn, sorghum and related products including distiller’s dried grains with solubles (DDGS) and ethanol. With full-time presence in 13 key markets and representatives in an additional 15 locations, the Council operates programs in more than 50 countries and the European Union. The Council believes exports are vital to global economic development and to U.S. agriculture’s profitability. Detailed information about the Council and its programs is online at www.grains.org.
About the National Corn Growers Association
Founded in 1957, the National Corn Growers Association represents nearly 40,000 dues-paying corn farmers nationwide and the interests of more than 300,000 growers who contribute through corn checkoff programs in their states. NCGA and its 50 affiliated state associations and checkoff organizations work together to create and increase opportunities for their members and their industry.
Thanks to the adequate rain fall within the past few months, winter planted dryland oats are being harvested, baled,and hauled for livestock feed. Wheat and alfalfa continue to mature. Forage crops will soon be ready to be cut forhay or silage Windy days will increase lodging in mature wheat fields which will cause issues at harvest. Groundpreparation is starting for spring forage and row crops. Cover crops are still being incorporated into the soil.
DECIDUOUS TREE FRUITS, NUTS, AND GRAPES:
Thinning of late variety stone fruit trees is ongoing. Immature stone fruit continues to develop. Early varieties ofapricots, plums, peaches, and nectarines have started with exports to Brazil. Cherry harvest has begun, with theTioga variety being picked for domestic markets. Reflective sheeting has been put out to aid in the fruit coloring forcherries. Yields for cherries this year look promising, weather permitting. Nutrient sprays and pesticide applicationsof fungicides and herbicides are starting for both vineyards and orchards. Mechanical vineyard maintenance isstarting with vine training. Leaf pulling in grapevines continues to allow for improved air circulation and lightpenetration around the developing bunches. Walnuts and pistachios are starting to bloom. Last season’s pistachionuts are being exported to the European Union, Turkey, China, New Zealand, Spain, and Vietnam. This season’salmonds are progressing nicely. Almonds from storage are being exported to India, Hong Kong, the Philippines,Japan, the Netherlands, Israel, Malaysia, South Africa, Korea, the United Kingdom, and Italy.
CITRUS, AVOCADOS, AND OLIVES:
Late Lane navel oranges are nearing the end of the season, with a moderate decline in fruit quality and demand. Fruitdrop and softening are becoming serious issues. Domestic and international exports for late navels are steady; withfruit being exported to Japan, China, Korea, Southeast Asia, Ecuador, and Mexico. Valencia oranges continue to bepicked and packed for both the domestic and international markets. International exports for Valencia orangescontinue to China, Japan, and Korea. As the Valencia season progresses, exports will intensify to internationalmarketplaces. Grapefruit harvest is nearing the end, but exports of Star Ruby grapefruit to Korea, Japan, and Mexicoare on-going. Seedless tangerine groves remain covered with nets to prevent pollination during the bloom period. Citrus grove mechanical maintenance is starting with trees being thinned, topped, and/or skirted. Some harvestedorange groves are being removed. Citrus bloom has been declared in all citrus groves around Tulare County. Lemonsare being harvested for domestic and overseas markets. Olive tree blooms are progressing.
VEGETABLES, MELONS, AND BERRIES:
Blueberries are being harvested, with exports being sent to Taiwan, Canada, and Japan. Blueberry harvest innorthern Tulare County should be starting within the next few weeks. Strawberry season is in full swing, withcontinuous bloom and mature fruit being picked for sale at roadside stands. Additional summer vegetable fields arenow being prepared for planting with warmer temperatures and ample soil moisture.
LIVESTOCK AND POULTRY:
Rangeland forage is in good quality condition, and mild rains have aided the new growth of grasses and forbs.Grazing conditions are good for local cattle ranchers. The fed cattle market is $126 per hundred-weight this week.
ADDITIONAL COMMENTS:
Local wholesale nurseries are gearing up for the spring rush, with shipments of nursery stock to both local and out-of-state nursery outlets. In preparation for Mother’s Day and balmier weather, retail markets are increasing theirinventory of annual and perennial flower and foliage plants. Bare-root roses continue to be processed but will soonhalt. Full sized olive trees are being removed from the ground and shipped for planting in ornamental landscapes.
End of the citrus bloom period for citrus grown in District 2 beginning at 1:00 a.m., Friday May 3, 2019.
USDA extended the deadline to May 17 from May 1 for agricultural producers to certify 2018 crop production for payments through the Market Facilitation Program (MFP), which helps producers who have been significantly affected by foreign tariffs, resulting in the loss of traditional exports. USDA’s Farm Service Agency (FSA) extended the deadline because heavy rainfall and snowfall have delayed harvests in many parts of the country, preventing producers from certifying harvested production.
Payments will be issued only if eligible producers certify before the updated May 17 deadline.
The MFP provides payments to producers of corn, cotton, sorghum, soybeans, wheat, dairy, hogs, fresh sweet cherries and shelled almonds. FSA will issue payments based on the producer’s certified total production of the MFP commodity multiplied by the MFP rate for that specific commodity.
“Trade issues, coupled with low commodity prices and recovery from natural disasters, have definitely impacted the bottom line for many agricultural producers,” said FSA Administrator Richard Fordyce. “The MFP payments provide short-term relief from retaliatory tariffs to supplement the traditional farm safety net, helping agricultural producers through these difficult times. Weather conditions this fall, winter and early spring have blocked many producers from completing harvest of their crops, and we want to make sure producers who want to finalize their MFP application have an opportunity.”
U.S. Secretary of Agriculture Sonny Perdue launched the trade mitigation program to assist farmers suffering from damage because of unjustified trade retaliation by foreign nations. FSA implemented MFP in September 2018 as a relief strategy to protect agricultural producers while the Administration works on free, fair and reciprocal trade deals to open more markets to help American farmers compete globally. To date, more than $8.3 billion has been paid to nearly 600,000 applicants.
The MFP is established under the statutory authority of the Commodity Credit Corporation Charter Act and is administered by FSA.
Emission devices or emitters are vital component of drip/microirrigation systems as they control the dripping (emission) of water and fertilizer solution to the plant.Drip emitters basically slow down the flow rate to a “trickle” by dissipating the energy of the flow through frictional resistance.This makes it possible to deliver water and fertilizer solution to the plant in a frequent localized manner and at, essentially, constant rate; and that is the principal advantage of this method of irrigation.
Efficiency of a drip irrigation system refers to the ratio of the water delivered to the plant to satisfy its water requirements to the total applied water.High efficiency of a drip system is usually desired. Emission uniformity (EU) is a prerequisite for the high efficiency of the system as will be explained later.
Though drip systems are designed around EU, emission uniformity of the system is also influenced by the emitter selection.Therefore, the emitter should be selected prior to the initiation of the system design.Changing the emitter choice after completion of the design could degrade the system.Proper selection of emitter enables using smaller diameter laterals, longer laterals or less sub-main lines which means less costly system while maintaining the desired system uniformity and efficiency.
To help you select the appropriate emitter, a discussion of emitters flow characteristics are presented followed by a description of some of the commonly used types of emitters.A guideline for emitter selection is then provided.
Emitter Flow Characteristics
Drip emitters regulate water flow by dissipating the flow energy through frictional resistance.Laminar flow emitters regulate water flow by dissipating energy via friction against the walls of long and narrow path.Microtubes and spiral path emitters are examples of laminar flow emission devices.
On the other hand, turbulent flow emitters regulate water flow by dissipating energy by friction against the walls of the water passage and also between the particles themselves during their turbulent movements.Orifices, nozzle emitters, tortuous path emitters and jets or sprayers are typically turbulent emitters.The drip tapes that utilize orifices are also turbulent flow devices.
Laminar Flow Emitters
In a laminar flow the fluid particles move along parallel paths in layers or laminas.The magnitude of the velocities of adjacent laminas is not the same and liquid viscosity (i.e., resistance to poring) is dominant in controlling liquid movement and suppresses any conditions that may cause turbulence.
Hydraulic investigations showed that in a laminar flow, the flow rate “Q” of the emitter is directly proportional to the operating pressure and a change in operating pressure will produce an equal percentage of change in flow rate, i.e., if (H1/H2) = 1.1, then (Q1/Q2) = 1.1, and a change of 10 percent in operating pressure would result in a change of 10 percent in flow rate.
Therefore, the flow rate through laminar flow emitters is pressure sensitive (i.e., less pressure compensating, see turbulent flow emitters below).It is also temperature sensitive since it is influenced by the changes in viscosity of water which changes with temperature, i.e., the higher the water temperature the lower the water viscosity and the larger the discharge rate Q.Laminar flow emitters are also more susceptible to clogging because of their low flow velocity and their relatively long and narrow flow path.However, laminar flow emitters are inexpensive and with proper system maintenance will have satisfactory performance.These emitters are more suitable for short run laterals, where head loss is not very large and flow rate would not suffer large change between emitters.
Turbulent Flow Emitters
In turbulent flow the particles of the fluid moves in a haphazard fashion in all directions.While the viscosity is dominant with laminar flow, both inertia (that property of matter because of which a force must be exerted on a body in order to accelerate it) and viscosity affect the turbulent flow pattern.
Therefore, for turbulent emitters hydraulic investigations showed that the flow rate Q will vary with the square root of the operating pressure H, i.e., Q1/Q2 = [H1/H2]1/2 , and a change in operating pressure H of 10 percent would produce a corresponding change in flow rate Q of only 5 percent, i.e., if[H1/H2] = 1.10, then Q1/Q2 = [H1/H2]x = [H1/H2]1/2 =1.05.Thus, turbulent flow devices are less sensitive to pressure variations (more pressure compensating) than laminar devices, i.e., the same pressure change will produce much smaller change in discharge rate with turbulent flow emitters than with laminar flow ones.
The practical application of this conclusion is that if all other factors being equal, the length of laterals for turbulent drip tape for a given design uniformity could be longer than those of laminar drip tape while maintaining the same desired value of EU.Where the length of the lateral line is fixed (e.g., by field dimensions) the use of turbulent drip tape, for instance, will result in higher uniformity than laminar one due to less flow rate variation with turbulent flow.Hydraulic investigations also showed that the flow rate, Q, with turbulent flow emitters is independent of viscosity and therefore it is much less affected by water temperature than laminar flow emitters.Moreover, the flow path of the turbulent emitters is wider than that of the laminar flow ones which make them less susceptible to clogging than the laminar flow emitters.
Discharge Exponent, x
The exponent “x” mentioned above is usually referred to as the “discharge exponent”.The value of this exponent is usually close to unity (≈ 0.7 – 0.8) for laminar flow emitters and about 0.5 – 0.6 for turbulent flow emitters.
Coefficient of Variation, Cv
Manufacturing variability is a common industrial phenomenon where no two items are made exactly the same particularly for items of very narrow internal passages such as drip emitters.A minute change in the dimension of these passages could make a significant difference in the emitter discharge rate especially the pressure compensating ones.The coefficient of manufacturing variability for the emitter (Cv) is used as a measure of expected variations in discharge of new emitters from the average discharge, qa, of a particular sample of the given emitters when operated at a constant pressure head.Usually, emitter manufacturers provide the values of Cv for their products.
The discharge rate of representative sample of emitters operating at a given pressure essentially follows a bell-shaped normal distribution curve. Where qais the average emitter discharge, approximately 68 percent of the discharge rates fall within (qa ± Cv) , 95 percent of the discharge rates fall within (qa ± 2 Cv), and 99.7 percent of the discharge rates fall within (qa ± 3 Cv).
This means that for Cv values of 10% (0.10)samples of emitters with qaof 1gph, 68 percent of emitter discharge rate would fall within the discharge range of (qa ± Cv) or0.9 to 1.1 gph, 95% percent of emitter discharge rate would fall within the range of (qa ± 2 Cv) or 0.8 to 1.2, and 99.7 percent of emitter discharge rate would fall in the range of (qa ± 3 Cv) or 0.7 and 1.3 gph respectively.
Also for Cv values of 5% (0.05) samples of same emitters. 68 percent of discharge rate would fall within the discharge range of (qa ± Cv) or 0.95 to 1.05 gph, 95% of discharge rate would fall within the range of (qa ± 2 Cv) or 0.9 to 1.1, and 99.7 percent of discharge rate would fall in the range of (qa ± 3 Cv) or 0.75 and 1.25 gph respectively.
Therefore, the smaller the Cv value of a given sample of emitters the less different, or the more uniform, is the sample and the better the emission uniformity (EU) of water in the field.Table 1 provides the ranges and the common evaluations (classification) of Cv values.
Table 1. Coefficient of manufacturer variability, Cv
A higher Cv values, is used for line-source tubing because it is difficult to keep Cv and price both low.However, because line-source outlets are usually closely spaced the effect of higher Cv value on discharge uniformity is minimized.
Emission Uniformity, EU
Emission uniformity (EU) is a critical characteristic around which drip irrigation system is designed.EU indicates how uniform the system applies water in the field.High EU is a prerequisite for high efficiency.Irrigation efficiency could be expressed as how much of the applied water is added to the plant root zone.
It is not possible to acquire high efficiency with low uniformity, EU, because with low uniformity higher percentage of the field area will receive either less water or more water than the average application needed to satisfy the crop water requirements.To remedy this deficiency more water will need to be applied to the field to satisfy the requirements of the under-irrigated parts of the field.This will result in over-irrigating the rest of the field and that means more water is lost away from the root zone resulting in lower irrigation efficiency.
With high EU, only small percentage of the field will be under-irrigated and the volume of water needed to provide for the under-irrigated parts of the field will be much smaller, the losses will be smaller as well, therefore, the efficiency will be higher.However, it is possible to have a low efficiency with high EU.This is not contradictory to what was previously stated that high EU is a prerequisite for high efficiency. For example, if high EU is achieved in a field but excessive amount of water is applied to that field by applying irrigation water for much longer period of time than scheduled for delivering the estimated water requirements of the crop (i,e., over-irrigation) then, large amount of water will be lost away from the root zone and the irrigation efficiency will be low despite the achieved high EU.
Fig. 1. Typical layout of a microirrigated system
B:Types of Emitters
Emitters are usually grouped according to their flow patterns (e.g., laminar and turbulent flow), wetting patterns (e.g., point-source, line-source, multi-exit emitters), and special functions (e.g., pressure compensating and flushing emitters).Some emitters may combine more than one attribute, e.g., pressure compensating line-source emitter (drip tape).
Flow Pattern
* Laminar & Turbulent Flow Emitters
Turbulent flow emitters have the advantage of being less sensitive to pressure variation (i.e., more pressure compensating), less sensitive to water temperature variations, less susceptible to clogging and allow for longer lateral runs or less pressure variation for the same length of lateral run than laminar flow emitters.Laminar flow emitters are less expensive and more suitable for short-run laterals.On-line, in-line and drip tape come in either laminar or turbulent flow type.Both laminar and turbulent flow emitters may come in standard or pressure compensating type.
Wetting Pattern
*Point-Source and Line-source emitter
Drip irrigation with water discharged from emission points that are rather widely spaced, usually 3 ft or more, is commonly referred to as point-source application.When water is discharged from more closely spaced outlets it is called line-source application.Examples of point-source is on-line and in-line emitters (see Fig’s. 2 & 3).The most common discharge rate of point-source emitters is 1 gph.Other available sizes are 0.5, 1.5, 2.0 gph.Point-source emitters come in standard and pressure compensating models.
On-line emitters are commonly used for irrigating orchards and vineyards.The PE (polyethylene) laterals are usually laid on the ground surface (see Fig. 2).This type of emitters offers the user the advantage of installing an emission device exactly where wanted and the emitters are serviceable.Their disadvantage is that the end user must manually insert each emitter.
In-line emitters or drip lines are similar to on-line emitters but in this configuration they are pre-inserted into the PE tubing at specified intervals during the tubing extrusion process (see Fig. 3).The emitters may be cylindrical or flat “boat shaped”, and are attached to the inner tube wall via a controlled heating/adhesion process.Labor savings for the end user may be substantial since emitters are factory pre-installed.The drawback is that emission devices may exist where not needed, and they are not serviceable. Drip-line may be installed below the surface such that the soil surface may be kept dry.Both on-line and in-line emitters come in regular and pressure compensating types.
Examples of line source are single chamber and double chamber drip of relatively thin tubing, commonly known as “drip tapes” (see Fig. 4).Single chamber tubing has orifices punched or more complex emitters fabricated or inserted at intervals of 2 ft or less along the tubing.Double chamber tubing is a hose that has both a main and auxiliary bore separated by a single wall.Widely spaced inner orifices are punched in the separator wall between the main and the auxiliary bore; for each inner orifice, three to six exit orifices are punched at intervals of 0.5 to 2 ft in the outer wall of the auxiliary bore.
Drip tape may be classified according to their flow pattern as either turbulent or laminar.Turbulent drip tape controls flow rate by means of orifices or tortuous flow paths, while laminar tape utilizes small tubes or capillaries to control flow rate.These two types of drip tape exhibit different flow rate response to pressure variation (as explained earlier) and they are not mutually exchangeable for the purpose of system design.
Water is distributed evenly along the length of the drip tape through emission devices that may be spaced anywhere from 4” to 24” apart.Tube wall thicknesses vary from .004” to .015” (4 mil to 15 mil), emitter flow rates from 0.07 to 0.34 gph, and tube diameters from 5/8” to 1-3/8”.Drip tape is used extensively for irrigating vegetable and field row crops e.g., strawberries and tomatoes.It may be installed above or below the ground, and may be retrieved for multi-season reuse or disposed of at the end of each season.Drip tape is relatively inexpensive and is ready to install without any additional emission device installation labor.
*Sprayer, Jets or microsprinklers(see Fig. 7 & 8)
These are small applicators designed to spray water to cover an area of 10 to 100 ft2.Jets are mounted on risers or stakes (see Fig. 8) and spray water through the air as separate streams that create various foot printpatterns of water in the soil.A variety of patterns are available including full circle, half circle, hi/low trajectory, butterfly, etc.The versatility of patterns provides a great deal of flexibility for the end user to accurately apply water only where wanted, such as enveloping each tree in an orchard without wetting the trunk.Wetted diameter ranges from 10 to 35 ft and discharge rate from 5 to 30 gph.Flow through jets is turbulent with discharge exponent x = 0.5.Jets are commonly used on orchard crops like almond and citrus and on light textured soils.
Special Function
*Pressure-Compensating Emitters
This type of emitters provides varying degree of flow regulation with discharge exponent “x” value ranging from 0.0 to 0.4.For complete flow regulation x = 0.0.Pressure compensating devices may be either laminar or turbulent.In either case, these devices utilize the inlet pressure to modify the flow path size, shape or length.In this way, pressure-compensating devices are able to deliver the correct flow rate over a fairly wide range of inlet pressures, and within that range their flow rates are relatively constant.Pressure-compensating emitters are useful for use in undulating fields.
Pressure compensating emitters suffer from the drawback that the elastomeric material used in their construction has a tendency to change their properties as they age. The following graphs (Fig’s. 9 & 10) show the difference in performance between pressure-compensating and non pressure-compensating emitters.
*Flushing Emitters
This type of emitters is designed to have a flushing flow of water to clear the discharge opening every time the system is turned on.Continuous flushing emitters permit continuous passage of large solid particles whileoperating.Some on-line emitters and drip tape are manufactured with flushing capabilities.
*Multi-Exit Emitters(see Fig. 6)
Some on-line emitters supply water to two or more points through small diameter auxiliary tubing; they are used in orchards where large trees may require several emission points for each tree.They are usually more expensive than single exit emitters.
E.A Guideline for Emitter Selection
The pressure variation within the system and the flow characteristics of the selected emission devices influence the uniformity of water distribution (EU) of a drip/microirrigation system.While the control of pressure variation by proper system design is certainly required, the selection of the emitter device itself is also vital for achieving the desired high EU and high system efficiency (e.g., x & Cv).Moreover, emitter selection is critical for specifying the water treatment and the filtration equipment for the drip system.Filtration requirement for a given emitter is specified by the emitter manufacturer.User preference might also be a factor and personal and local experience may influence the choice of emitter.
However, two very important items to be considered in emitter selection are the percentage area wetted, which is related to delivering the required amount of water to the plant at the design pressure, and the reliability of the emitter against clogging and malfunctioning.
It is recommended to provide a sufficient number of emission points to wet between one-third and one-half of the horizontal cross sectional area of the potential root-zone.Field observations have shown that the density of emission points required to obtain such percentage of wetting can be based on an assumed discharge of 1 gph emitters.For perennial crops, the number of emitters can be increased with the age of the plant and stage of growth.However, the initial pipe network must be designed to meet the needs of the mature plants.It is usually recommended that the filtration process should remove all particles larger than one-tenth the diameter of the emitter passage way.Also, regular flushing of laterals can significantly reduce emitter clogging (see Fig. 11).
Conclusion
Generally, the selection of an emitter depends on the soil to be wetted, plants to be grown and their water requirements, quality of irrigation water and emitter discharge. The cost ofemitter should be also be considered as the average total cost of emitters may amount to about 20-25 percent of the total cost of the system.The following points together with above provided explanations may provide a guideline for emitter selection.
First determine the general type of emitter that best fits the needs of the crop to be irrigated and the area to be wetted, i.e., continuous wetting pattern for vegetable crops where a drip tape could be suitable, on-line emitters for irrigating orchard crops,jets where relatively coarse textured soil prevails or where light water applications with large foot print could be more suitable for the crop requirements.The use of pressure compensating emitters may be advantageous for undulating terrain.
Second, according to the required discharge, spacing, and other field conditions, choose the specific emitter needed, i.e., which drip tape, jet pattern, or on-line emitter could be more fitting for supplying the water requirements of the crop, e.g.,for drip tape, is it going to be for one season, 4 mil, or for several seasons, 25 mil.Third, determine the required discharge (q) and operating pressure head (H) for the average emitter that fits the system design and prevailing conditions (e.g., water quality, soil properties, weather conditions).
It is also important to examine the emitter characteristics described above i.e., x, Cv, filtration requirements.Emitters with discharge exponent (x) closer to 0.5 is more pressure compensating, less sensitive to temperature changes and less susceptible to clogging than the ones with the value of x closer to one. The smaller the Cv value for the emitter the more uniform is water application in the field.Emitters with Cv between 0.03 to 0.05 are expected to provide higher EU and consequently higher system efficiency than the ones with Cv between 0.07- 0.09.
Filtration requirement as stated by the emitter manufacturer should also be considered, the smaller the required mesh number (number of opening per inch) the less susceptible the emitter to clogging.Emitters that require mesh number 160 is less susceptible to clogging than the ones that requires 260 mesh number for filtration.However, the filtration requirements as stated by the emitter manufacturer should be fulfilled.Also, enquire with emitter manufacturers regarding the tolerance of emitter components to chemicals such as acid and chlorine usually used for system cleaning and disinfection.Finally, local and personal experience should be taken into consideration.
For more information, visit www.agridrip.com or contact F.A.Hassan, an irrigation & Soils Consultant at Agro Industrial Management at “fahassan@aol.com“
With the largest pistachio crop ever in the west last year coupled with international trade issues, some might be concerned about prices and how to move such a large inventory; however, American Pistachio Growers (APG) reported that the demand is out there at their annual conference, and APG unveiled some exciting new marketing plans for the coming year, including a new market in India. Watch this brief interview with Judy Hirigoyen from APG, and read more about it in Pacific Nut Producer Magazine.
As California faces more frequent and severe droughts, agriculture, which relies on irrigation from surface water and groundwater, could become expensive and unsustainable. Researchers at the University of California, Davis, looked at using a “free” resource — rain water stored in the soil — and found that optimizing its use could go a long way to help meet demand for five California perennial crops. Their findings appear in the journal Environmental Research Letters.
