Farmers have always battled the elements, and they’re increasingly turning their eyes towards irrigation. Subsurface drip irrigation (SDI, or subsurface drip fertigation, SDF) is of particular interest due to the very low volumes of water involved, and the way SDF can deliver the right nutrients at the right time directly to plant roots.
SDI piping is laid down 10 to 20 inches beneath the surface of a field, orchard or vineyard. The emitters release water, with various nutrients added at specific levels and times depending on crop, plant growth stage, existing soil nutrient levels and so on.
Because SDF can result in impressive yields and its costs have come down, it continues to gain traction, particularly in high-quality crops and in semi-arid climates where evaporation greatly reduces the efficiency of overhead irrigation.
“Climate change and the threat of drought are definitely driving interest,” says Dr. Willemijn Appels, the Mueller Applied Research Chair in Irrigation Science at Lethbridge College in Alberta, Canada, where she has led a team of SDI and SDF researchers since 2018.
Appels and her colleagues have collaborated with Canadian firm Southern Irrigation, which has pioneered SDI use in Canada and has worked with Netafim (U.S.) for 35 years. Netafim (Israel) introduced the concept of SDI to the world, explains Southern Irrigation SDI sales rep Kees Van Beek.
“We have used their driplines for nurseries, market gardens, vineyards and greenhouses,” he says. “We installed the first 40 acres of SDI eight years ago in Gem, Alberta.” Across Canada, there are about 1,500 acres under SDI, mainly in Alberta, with a little in British Columbia and Saskatchewan. Southern Irrigation installed its biggest SDI field, 620 acres, in 2020.
Worldwide, Van Beek reports that millions of acres are irrigated with SDI on a wide range of grain, forage and fibre crops including alfalfa, canola, corn, cotton, soybeans and sugarcane. He says India and the U.S. are large markets for SDI, with extensive use of SDF in U.S. states such as Iowa and Idaho for corn and soybeans. All Mideastern countries use SDI, he notes, and most new irrigation acres in Africa are also SDI.
In Van Beek’s view, the potential for further adoption is very large. Along with all its benefits, SDI avoids the limiting factors of overhead (pivot) irrigation. Wind, for example, causes huge evaporation losses with overhead systems. The regular water spray can also be a significant cause of foliar diseases and crop lodging. Compared to SDI, overhead systems also have more moving parts, which means more maintenance.
But in Van Beek’s view, “the main driver for SDI will be the water savings. We use 30 percent less water and we are 98 percent efficient.”
Low flow Emitters have become smaller over time so they can accommodate very low flow rates. “The smallest ones I’ve used emit 0.11 gallons per hour,” notes Appels.
Van Beek says Netafim is the only manufacturer that makes these. He explains that with the use of these emitters, “we can run longer driplines while not increasing the dripline diameter. This helps with keeping the cost down. This low flow emitter matches the soil infiltration rate better, and we can run longer irrigation cycles.”
Van Beek says he believes that in the future, we will even see lower flow rates. Emitters will keep evolving, he notes, “and so will be the products we can inject to control the various aspects of crop health.”
Appels also notes that emitter designs have been improved such that roots and soil particles cannot plug the lines. The emitter holes are not big to start with and they only open when there is water pressure. More sophisticated pumping and filtration systems have also emerged, she says, along with continued improvement to automatization and remote control.
Field crop use Already, reports Van Beek, “we know how and when to fertigate on crops like corn, soybeans [and] alfalfa from U.S. data, and we are learning to boost yields on canola, various kinds of wheat and other crops not grown on SDI in the U.S. With SDF, we have seen yield increases of up to 58 percent compared to pivot irrigation.”
According to Appels, there is increased interest from large-scale agriculture in Canada to use SDF with high-value crops such as canola and wheat (durum and winter wheat), but also hemp, timothy, alfalfa, silage corn and pinto beans.
“It may seem crazy at first to install it in an 800 metre by 800 metre block where every metre has a dripline – that’s kilometres of dripline – and grow canola on it, but the net returns can be worthwhile,” she says. “With a pivot on a square field you are going to miss some corners, but with SDI, you cover all the land. And using less water than with a pivot you can still get a good crop. It’s easy to automate, but you need the research to know when to apply water and fertilizer, how much fertilizer and so on.”
Study results There are multiple SDF projects going on at Lethbridge College, some in collaboration with industry partners. Here are details on some of them.
Over the last three years, Appels’ colleague Dr. Rezvan Karimi Dehkordi has studied how SDF can be used to maximize yields in field crops. Working with Southern Irrigation and First Fruit Farms near Lomond, Alberta, she has tested different SDF applications on durum wheat in 2019 and pinto beans in 2020. The 2019 study found durum wheat crops treated with subsurface fertilizers had higher levels of nitrogen and phosphorus uptake as well as higher yields. However, the 2020 study was affected by wet weather, and no significant differences emerged between study and control crops.
“When we have a lot of rain, the management of fertilization is complex with SDF,” says Karimi. “Early in a wet growing season, you would apply fertilizer on top of the soil and when it dries out, you can use fertigation, perhaps using higher concentration of fertilizer.”
In 2021, Karimi did greenhouse experiments examining the effect of fertigation frequency on nitrogen use efficiency and microbial communities in canola (which has a taproot) and barley (fibrous root). Analysis of data is going on right now. In 2022, at the new Lethbridge College demonstration farm, Karimi
and her colleagues will compare fertilizer applications using different ratios of solid fertilizer applied to the surface, to fertigation via SDI over time, and at what concentrations to best boost yield.
Water availability For any type of irrigation anywhere in the world, farmers must be part of an irrigation district, with all parties removing water (such as municipalities and other industries) requiring a license for specific volume withdrawals over time. Van Beek says that in Alberta, there are over one million acres irrigated through 13 districts. Wells, runoff and dugout water storage are used as sources for irrigation in central Alberta and increasingly in Saskatchewan, Manitoba and further east in Canada.
“In southern Alberta,” says Appels, “we irrigate with surface water from a reservoir or river, transported by canals and pipelines to all in the network. The volume of water available is very dependent on snow melt. In the U.S. Midwest, they’ve had water volume problems because their licences were for too much water and in many cases, they use aquifers which recharge slowly.” However, she notes that water availability problems happen with surface water sources too. “In Alberta this year due to lack of rain,” she says, “the Milk River level dropped and farmers had to stop withdrawing for irrigation.”
Aquifer use in Alberta wouldn’t likely be an option, adds Appels, as most of the groundwater is found too deep below the surface and the water may be salty.
Cost comparison At this point, the cost to install SDI is higher than pivot irrigation. Each potential SDI adopter must of course investigate their options closely with a focus on potential benefits and ROI. This analysis, says Van Beek, includes all input costs, past yields, crop rotation, soil classification and more.
“We take a very detailed approach to new SDI projects,” he says. “We look at the elevations, soil structure, soil horizons, water source and quality, crop rotation and rodent pressures to ensure success and a long-term relationship with our customers with agronomy support.” ●
SDI piping is laid down 10 to 20 inches beneath the surface of a field, orchard or vineyard. Photo: Southern Irrigation
Testing subsurface drip irrigation (SDI) in the lab. Photo: Lethbridge College
Dr. Willemijn Appels
Dr. Rezvan Karimi Dehkordi
San Diego, California
Excitement is building as plans are being finalized for the 2021 Irrigation Show and Education Week. This year’s show will be offered live and in person Dec. 6-10 in San Diego, California. Registration is open, with the best rates available through Oct. 31.
The Irrigation Association is looking forward to inviting the industry back together again for this annual exhibition focused on agriculture and landscape irrigation. The 2021 Irrigation Show provides attendees the chance to see innovative products and smart solutions, find new suppliers, learn about current business trends and irrigation best practices, and network with industry leaders. The best part is that it is all in person.
Focus on the show floor This year the IA is putting all of its efforts into demonstrating innovation and helping attendees build business connections on the show floor. Walking the exhibit hall aisles offers the perfect opportunity to engage with the industry’s best companies and get a firsthand look at all of the latest products, services and technologies in agricultural irrigation.
The new Innovation Row is a special area in the exhibit hall specifically for startup irrigation technology companies looking to promote their technologies to the irrigation industry. Check out Innovation Row to get a sneak peek into the future of irrigation and then watch these startups take the stage in a Pitch Competition at the Innovation Hub on Dec. 8.
In addition to the Pitch Competition, the Innovation Hub area will feature a variety of product demos and the announcement of the winners of the Pitch Competition and the 2021 New Product Contest. Similar to past shows, the new product contest entries will be displayed in a special section on the show floor. This provides a rare opportunity to see the latest products and technologies up close and in person. The contest judging will take place online Nov. 17-18, and the digital presentations are free to watch. The winners will be announced on Dec. 9 at the Innovation Hub.
At the end of the first day of the Irrigation Show, attendees can enjoy a Craft Brewfest reception on the show floor. This is the perfect opportunity to enjoy local beers and take some time to catch up with colleagues and make new business connections.
Irrigation Symposium and IA University This year’s show offers a special educational event that only happens every 10 years. The American Society of Agricultural and Biological Engineers and the IA are hosting the 6th Decennial National Irrigation Symposium. This unique event will include three days of presentations about the recent progress and status of irrigation research, extension, planning and management activities.
These presentations vary from 20 to 25 minutes with scheduled time for questions and comments from the audience. They will help chart a path for irrigation progress in the next 10 years.
In-person IA University classes are returning to the show this year. These courses consist of core curriculum for fundamental skill sets. The classes are offered every year to ensure you and your employees have the foundational and practical skills necessary to design, install or maintain an irrigation system, as well as the business skills to manage a small irrigation company. These classes require an additional fee and preregistration is encouraged to ensure a seat.
Leave time for fun If you have ever travelled to sunny San Diego, you’ll understand why the city is consistently named a top meeting destination in the
United States. In addition to year-round sunshine and near-perfect weather, San Diego is soaked in culture and offers 70-plus miles of sparkling coastline, friendly locals, a vibrant downtown and an endless assortment of unique neighbourhoods to explore.
While you are in the country, we hope you will take the time to enjoy everything San Diego has to offer. Whether you want to learn how to surf in La Jolla, taste the local flavours in the Gaslamp Quarter, stroll the peaceful beaches of Coronado, explore the museums of Balboa Park or take a cruise on the bay, San Diego has something for everyone.
San Diego’s climate makes it the ultimate year-round destination. Days are frequently warm, even in winter, and evenings are cool. In December, San Diego boasts an average high of 66 degrees Fahrenheit and a jacket-weather low of 50 degrees Fahrenheit.
Focus on safety The IA is committed to making every effort to keep our participants safe during the show. We are monitoring both national and local guidelines to ensure that we are following the necessary practices to ensure a positive and healthy experience.
Please check the Irrigation Show website regularly, as the webpage containing the latest COVID-19 guidelines is updated as necessary to relay the possible impact of COVID-19 on the Irrigation Show. ●
Register now
Register by Oct. 31 to take advantage of the best rates. Go to http://www.irrigationshow.org/.org for more information about the show and San Diego, as well as housing options and registration information. We look forward to seeing you in San Diego as the industry reunites to explore, connect and learn.
This year the IA is putting all of its efforts into demonstrating innovation and helping attendees build business connections on the show floor.
Photos pages 11 and 12: Irrigation Association
Tasmanian farmers will benefit from an additional 80,000 megalitres of high-surety water per year thanks to five irrigation schemes being designed in partnership between Tasmanian Irrigation, professional services company GHD and Pinion Advisory.
The projects are part of the Tranche Three program, a joint investment between the Australian government, Tasmanian government and Tasmanian farmers to develop 10 irrigation schemes across agricultural areas of Tasmania. Funding is confirmed for the first five projects, with further funding to be sought for the remaining five schemes.
Current infrastructure limitations in some parts of Tasmania mean that water is not distributed efficiently for agriculture. Access to irrigation water will give landholders confidence to value-add, diversify and expand to incorporate new higher-value enterprises, such as viticulture or dairy.
In total the program and its 10 schemes will double Tasmania’s current irrigation capacity of 133,314 megalitres.
Tasmanian Irrigation Chief Executive Officer Andrew Kneebone said the company had sought a partnership with the design industry to strengthen its ability to design and deliver irrigation projects that met irrigators’ needs, whilst simplifying its offering to the construction industry.
“Tasmanian Irrigation welcomes the strength and innovation of the GHD and Pinion Advisory unique design partnership, which will reduce duplication, enhance cross-scheme learnings, simplify procedures and provide more certainty to contractors,” Mr Kneebone said. “Design specifications have been standardized for engineering, hydraulics, electrical plans, pumps, pipelines and dams, leading to a more consistent system control and data acquisition, as well as assisting with water delivery and asset management operations.”
GHD and Pinion Advisory will focus on the design of infrastructure including the pipelines, tanks, dams and pump stations associated with the Tranche Three projects. They will also provide technical support during early project phases and construction and commissioning. ●
The government of Madagascar has received US$40 million from the World Bank for irrigation development in the country.
The Sustainable Agriculture Project through a Landscape Approach (Projet d’agriculture durable par une approche paysage - Padap) is one of the Malagasy government’s solutions to mitigate the effects of erosion and land degradation, notably through the development of landscape-based agriculture.
According to Malagasy authorities, the World Bank loan will be used mainly to develop activities aimed at increasing access to irrigation services, notably through the rehabilitation of 14,000 hectares of irrigated perimeters, as well as sustainable agricultural techniques and practices in Madagascar.
The overall objective of the Padap project is to increase agricultural productivity in connection with sustainable management of natural resources in five selected landscapes, within four regions of Madagascar (Sava, Analanjirofo, Sofia and Boeny). Specifically, the aims of the project are to increase access to irrigation services and sustainable agricultural techniques and practices; and to strengthen the integrated management of natural resources in the targeted landscapes.
Padap will also encourage the promotion of agro-ecological practices and reforestation, notably through the restoration of 7,000 hectares of forest, as well as the management of ecosystems and protected areas.
At least 38,000 people, 40 percent of whom are women, will benefit from the impact of Padap, which was launched in June 2017. The project is expected to be completed in December 2022. ●
