A common nitrogen (N) fertilization practice in annual crops is to apply all the N in a single dose at crop seeding. But an increase in the greenhouse gas (GHG) nitrous oxide (N2O) has been linked to N fertilization in agriculture, especially in irrigated areas. Indeed, irrigation can further exacerbate this detrimental outcome as increases in soil moisture availability and decreasing aeration are known to lead to high N2O production.
But a recently published study demonstrates that in-crop N fertigation can diminish N2O emissions. The study, which was published in Science of the Total Environment, examined how splitting the total N fertilization into seeding time and in-crop fertigation impacts N2O emission factors (EF) in irrigated wheat (Triticum aestivum) and canola (Brassica napus) in southern Alberta, Canada during two growing seasons.
According to Guillermo Hernandez-Ramirez with the Department of Renewable Resources at the University of Alberta in Edmonton, and one of the study authors, the effect was particularly evident when using reduced N fertilization rates.
“Splitting the total N fertilization impacted N2O emission factors by reducing it in about half of the cases,” he noted. “As well, the study showed that most of the reductions in N2O emissions due to fertigation occurred with low and intermediate N rates (total rates of 60 and 90 kg N ha-1).”
Southern Alberta accounts for approximately 70 percent of the irrigated agricultural land in Canada. The most typical irrigation method in the region is sprinkler, and common annual crops include wheat and canola. Prior research has shown increased N2O emissions due to a combination of irrigation and higher fertilization compared with rainfed crops.
So, to test the effects of N fertigation on N2O fluxes, the study was conducted during two growing seasons (May to October) in sprinkler-irrigated wheat and canola. The study assessed a range of N fertilization rates with the N added all at crop seeding time or split into the seeding time and an in-crop fertigation.
Hernandez-Ramirez said the study’s second year had recurrent, early-season rainfalls following seeding (and prior to fertigation) that triggered differences in the daily and cumulative N2O fluxes. Within this second year, fertigation on wheat consistently lowered the growing-season N2O EF from a high of 0.27 percent to only 0.11 percent (P b 0.001). Also, at the intermediate rate of 90 kg N ha-1, fertigation synergistically reduced the N2O EF of canola by half, from 0.13 percent to 0.06 percent (P< 0.01).
The research also showed that mitigating effects of fertigation vanished with the highest N rate in the study (120 kg N ha-1). Even with fertigation, this highest N rate resulted in high emissions in wheat, but lesser so in canola in part due to the higher N uptake of canola. Moreover, canola often manifested narrower ratios of N2O emission-to-grain yield (EF-yield) than wheat. This interplay of crop species, rainfall and N management suggests that implementing fertigation with reduced N rates can proactively mitigates N2O.
“By delaying part of the N fertilization (with using N rates of 60 and 90 kg N ha-1 per season), we realized N2O emissions could be reduced,” said Hernandez-Ramirez. “When this is done intentionally as part of a management plan, we think that this is proactive mitigation.
“This is important because more than 70 percent of the irrigated croplands in Canada are located within this same region, so the results and insights from this research is relevant to an important component of the highly productive agricultural systems,” he added. “The greenhouse gases emissions footprint can be reduced, and this is important for access to markets. The supply chain is increasingly interested in sustainable sourcing, and greenhouse gases is one of the key indicators.”
In-crop nitrogen fertigation can effectively mitigate N2O emissions. Photo: Leanne Chai, U of A
New AG International NOV/DEC 2020
Mario Tenuta plans to resolve how 4R farming practices reduce emissions of the most important greenhouse gas emitted from soil. Photo: University of Manitoba
The University of Manitoba (Canada) has announced that agricultural and food Sciences soil science professor Mario Tenuta has been named the Natural Sciences and Engineering Research Council of Canada (NSERC) Industrial Research Chair (IRC) in 4R Nutrient Stewardship, with combined funding of CDN$2.93 million over five years.
The chair is awarded in partnership with NSERC, the Western Grains Research Foundation (WGRF), Fertilizer Canada and the University of Manitoba. Tenuta’s research will advance 4R nutrient stewardship, an innovative approach developed with the fertilizer industry, to apply the ‘Right fertilizer at the Right rate, at the Right time and in the Right place,’ to enhance production goals, farm profitability and environmental sustainability.
Tenuta plans to resolve how 4R farming practices reduce emissions of the most important greenhouse gas emitted from soil, nitrous oxide (N2O), as well as developing new practices and the training of students to improve the sustainability of farming systems in Canada. His research will specifically work to evaluate how nitrification inhibitors stabilize fertilizers and reduce N2O emissions and nitrogen (N) losses.
“Strengthening Canada’s role as a major exporter of agricultural commodities relies on using nitrogen fertilizers more efficiently and with fewer losses to the environment,” said Tenuta. “The adoption of 4R practices depends on convincing farmers through good practical science.”
Tenuta has already begun by initiating long-term studies to contrast the benefit of 4R practices on direct N2O emissions and indirect emissions as ammonia (NH3) and leaching N losses on different soil types. This research seeks to improve models of N2O emissions to include 4R practices and will summarize farm survey information to gauge the current use of 4R practices and opportunities for improvement. Tenuta will combine his findings with other studies to forecast the extent by which the adoption of 4R practices can help Canada achieve greenhouse emission reduction commitments.
“Fertilizer nitrogen is the highest operating cost in field crop production in Canada,” says Tenuta. “Our research and outreach are aimed at providing practical and feasible ways to improve crop productivity and reduce direct and indirect emissions of N2O and nitrate leaching.”
The COVID-19 pandemic has introduced challenges and obstacles throughout the irrigation industry. How has the Irrigation Association helped its members meet these challenges? As the COVID-19 pandemic initially began affecting the world in spring 2020, the Irrigation Association staff and leadership quickly realized the impact it would have on the irrigation industry and our member companies. As an association, we began refocusing our advocacy and operational efforts toward supporting our member companies and the industry in whatever ways possible. One initial response was to create a COVID-19 resources webpage, providing valuable links and information related to the IA’s advocacy efforts during the health crisis, federal resources for businesses and updates from industry-related associations. This webpage is still regularly monitored to provide the most up-to-date information and guidance. In addition, the IA has worked to provide as many virtual educational and informative opportunities as possible, including its Industry Insights webinar series that continues through April 2021, various online conferences and summits, and IA University courses.
At the end of October, the IA hosted Irrigation 20/20. What did these online interactive discussions focus on, and how well were they attended? Irrigation 20/20 was unique compared to any other digital event we hosted this year. The idea behind Irrigation 20/20 was to provide a more intimate discussion related to the IA, the industry and the challenges and opportunities ahead after the events of 2020. I was honoured to serve on a panel with incoming IA president Bryan Wynen, CIC, CLIA, CLWM, to discuss the future of the association. Irrigation 20/20 was also a great opportunity to hear from three distinguished IA award recipients: Brent Mecham, CID, CLWM, CIC, CLIA, CAIS; Stephen Smith, PhD, FASIC, CAIS, CLIA; and Lynda Wightman, CGIA, CIT. These accomplished individuals have a combined experience of over 125 years working in the industry. Their discussion about the future of irrigation in a post-COVID-19 world provided an interesting point of view for me as the moderator, as well as others watching this broadcast.
How would you describe the current state of the irrigation market, both in the US and abroad? The state of the irrigation market is strong. COVID-19 was and will continue to be one of the greatest challenges humans will ever face. In the early days of the pandemic, grocery store shelves were barren in many areas. More people than ever before became interested in where their food comes from. Now, agriculture is seen as a part of our nation’s (and world’s) critical infrastructure. The same goes for our outdoor spaces. Families were at home – quarantined – and many were scared to leave their property. Many families appreciated just what their outdoor space provided and began to invest in improvements. To this day, more people than ever before are truly appreciating the value of being outside, with their friends and families, in a safe way. Without irrigation, none of this would be possible.
Overall, what are the main issues facing the irrigation industry today?Uncertainty. There is a lot of uncertainty on what comes next. Will the raw materials be there when manufacturers need them? When will our economies truly open back up? Will our economy quickly rebound, or will it take time to get to where it once was? We are fortunate to be providing essential services, but long term, as this pandemic hangs on, will demand eventually decrease? This uncertainty is reigning true throughout both agriculture and landscape irrigation. Our technologies are there to boost productivity, while enhancing conservation. We are a resilient industry, but right now we, like many other industries, are anxiously waiting for the next chapter of COVID-19 to begin. Lastly, how can we best support our industry association? They rely on events for revenue to provide essential services back to the industry, so we must support them in other ways so we don’t miss a beat in advocacy and keeping our industry educated.
How is the IA working to address those issues? Fortunately, the IA, both our professional staff and volunteers, remain hard at work. While our 2020 Irrigation Show and Education Week may be cancelled, our mission to promote efficient irrigation has not stopped. On Nov. 5, we hosted our first-ever virtual Agricultural Irrigation Summit, where we talked about the many challenges facing agriculture and our solutions to help farmers meet these challenges. We continue to offer education, advocacy and all of the other critical elements of our strategic plan to ensure our member companies and industry remain successful during these challenging times.
Is the IA planning on hosting a 2021 Irrigation Show & Education Week?Definitely! IA staff are currently engaged in planning the 2021 Irrigation Show and Education Week in San Diego, California, Dec. 6-10. The IA understands the importance of our industry being able to gather together every year to allow in-person networking, face-to-face business meetings and hands-on instruction. However, we realize that COVID-19 has altered the way we do things, and as a result, we are making plans and adjustments to ensure that those attending can have a safe experience. Watch www.irrigationshow.org for updates on the 2021 Irrigation Show.
Jon Topham, President, Irrigation Association
Another 200,000 acres of southern Alberta (Canada) farmland will be irrigated in coming years as a result of a CDN$815 million injection into the region’s agriculture industry. That will add to the existing 1.5 million acres already under irrigation in the southern part of the province.
The funds will be used to build four new off-stream water storage reservoirs, adding to the current 50, and pay for 56 modernization projects, most of which involved conversion of open canals to underground pipelines.
Eight of Alberta’s 13 irrigation districts have formed a consortium to provide 20 percent of the funding, or about $163 million. About $245 million will come from the Alberta government and the remaining 50 percent, or $407 million, comes in the form of a loan financed by the Canada Infrastructure Bank (CIB).
That amount will be repaid by the irrigation districts over a period of 35 years, with the option to renew after that, and will be amortized over 50 years.
The $407 million from the CIB is part of the $1.5 billion for irrigation projects that was announced Oct. 2, which in turn was part of a $10 billion national infrastructure plan to be implemented over the next three years.
The eight participating irrigation districts are Bow River, Eastern, Lethbridge, Northern, Raymond, St. Mary River, Taber, United and Western.
Agricultural processing related to irrigation currently generates about $2 billion in annual sales and 18 percent of total provincial food processing sales. The provincial agriculture dept has calculated that the investment will add $436 million in GDP growth once projects are complete. The work is expected to create up to 1,300 immediate construction jobs and up to 6,800 direct and indirect jobs.
Of the $815 million, $520 million will be used for the new reservoirs and about $295 for the modernization projects.
Agriculture accounts for about 70 percent of global freshwater use, and as the population grows, so will demand for water. At the same time, global warming is increasing water loss through evapotranspiration, and intensifying the risk of drought in many regions. This confluence of factors makes it vital to improve the efficiency of irrigation so farmers can produce enough food for the more than nine million people predicted by 2050.
According to the International Potato Center (CIP), potato has good potential to help the world meet that challenge, since it produces more calories per litre of water than other major staple crops. That’s why scientists at the CIP are trying to enhance that potential through the development of digital tools to optimize the use of water in irrigation.
A team of researchers led by crop ecophysiologist David Ramírez has used a combination of conventional and thermal cameras to study how potato plants react to water stress. In field studies in the rain-deprived coastal desert of Peru, they shot infrared and visible images of a potato crop at different times of the day to detect changes in the temperature of the leaf canopies that are part of potato’s response to drought stress. They also developed open-access software called Thermal Image Processor (TIPCIP) to analyze those images, and created an early-drought-stress index to identify an indicator for when potato plants reach the threshold at which they need to be watered or their yields will be compromised.
By irrigating only when the plants reached that threshold, the researchers were able to greatly reduce the amount of water used in irrigation without provoking yield loss – an approach that farmers can use in areas where water is scarce to optimize their water use.
“Our research shows that through a combination of monitoring with thermal cameras and drip irrigation, farmers can reduce the water needed to produce a good potato harvest by at least 1,600 cubic metres per hectare, which is about 40 percent less than is used in traditional surface irrigation systems,” said Ramírez.
He explained that on large farms, thermal cameras can be mounted on unmanned aerial vehicles to monitor water stress, but this method is prohibitively expensive for most small- and medium-sized farmers. As an alternative, Ramírez has tested a more affordable option – a plug-in device that transforms a smartphone into an infrared camera, which costs around US$200 with support from the CGIAR Research Program on Roots, Tubers and Bananas. CIP scientists have developed a user-friendly version of TIPCIP to analyze smartphone images, and are planning a future version of the program to provide farmers with more specific information about when and with how much water to irrigate.
“Through the use of open-access technology and affordable tools, we can help farmers produce food with less water,” affirmed Ramírez.
A combination of better water management and drought-tolerant varieties could greatly enhance the potato’s resilience in future climates and enable its cultivation in regions where little or no food is currently grown, or during dry months when farmland now lays fallow.
But the technology alone is not enough. Ramírez added that such advances need to be complemented by policies that promote more efficient and sustainable management of water resources.
As climate change and population growth advance, such improvements can help ensure that potato growers, and farmers of other crops, can continue to produce the nourishment the world needs while staying within the planet’s ecological boundaries.
Viridix, a developer of data driven precision irrigation systems, and Talgil, a manufacturer of professional irrigation controllers, are partnering to provide farmers with an integrated precision irrigation solution. This solution allows farmers to automate full irrigation cycles from defining irrigation plans, to making sure each plot gets the right amount of water.
Farmers can now define and implement an irrigation protocol that delivers their production goal. Viridix’s highly accurate, low maintenance sensors constantly monitor soil moisture at varying ground depths.
The system analyzes data to calculate required irrigation volume and timing, and automatically adjusts the irrigation plan. The Talgil irrigation control system then executes the plan to provide plants with the right amount of water needed. The Talgil irrigation controllers ensure that no matter how many plots a grower cultivates, each one receives the exact amount of water it needs.
“Viridix and Talgil are a natural fit,” said Tal Maor, Viridix CEO. “Through this collaboration, we are able to close the precision irrigation loop and offer growers the advanced level of automation they need to meet their production goals in an efficient and sustainable manner. Both companies leverage advanced technology with minimal hassle, so it makes sense to create this joint offering that delivers greater value than each system separately.”
According to Yosee Ochman, deputy general manager at Talgil, the collaboration with Viridix adds an important dimension to the value the company delivers to its customers – data. “Our customers no longer have to manually calculate irrigation plans for different plots, or manually adjust them for changing weather conditions,” said Ochman. “Viridix provides precise and highly granular irrigation prescriptions implemented across plots. Real-time data from soil and water helps close the operational loop and ensure water goes where it should.”
Viridix and Talgil are partnering to provide farmers with an integrated precision irrigation solution. Photo: Viridix