Lethbridge College study finds fertile ground for subsurface irrigation research

A research project by Lethbridge College researchers is breaking new ground in the study of subsurface drip fertigation (SDF).

The two-year study is led by Dr. Rezvan Karimi Dehkordi, research associate on the Mueller Applied Research in Irrigation Science team and funded by a grant from the Canadian Agricultural Partnership. It explores how using SDF, a method that applies water and fertilizer directly to the rootzones of plants, affects uptake of nutrients crop yields.

Subsurface drip irrigation (SDI) is gaining popularity in Alberta, currently covering 1,090 hectares of field crop area. While SDI has been shown to provide benefits such as more efficient water use compared to surface irrigation methods, there are few scientific studies on subsurface fertigation specific to Alberta crops and soil conditions.

“Most of the data we have is from the U.S. on crops like alfalfa, cotton and soybeans,” says Karimi. “We don’t have enough information for Alberta farmers specifically on the best timing and rate of application. Without independent local data, it is not possible to provide realistic scenarios to agricultural producers about the value of SDF.”

Karimi worked with First Fruit Farms near Lomond, Alberta to test different fertilizer applications on durum wheat in 2019 and pinto beans 2020; she then compared the results with a control crop that did not receive any fertilizer. The 2019 study found durum wheat crops treated with subsurface fertilizers had higher levels of nitrogen and phosphorous uptakes as well as higher yields. However, the 2020 study of pinto beans found no significant difference between the study and control crops, which Karimi says is due in part to the wet conditions in the 2020 growing season.

For First Fruit Farms owner Matthew Wiens, the research partnership was an opportunity to validate some of his own observations from using SDF.

“Dr. Karimi and her team provided a lot of the data collection the sampling and counting,” Wiens said. “Instead of just getting a yield result at the end, we could watch how the fertigation was affecting the plants throughout the season so in the end we’re starting to better pinpoint the timing of the fertigation and when is it the most helpful within that plant’s growth cycle.”

Karimi says this study is a first step in determining whether the agronomic and economic benefits of subsurface irrigation and fertigation are enough to justify the higher cost of these systems compared to the alternatives. The recent announcement transferring operation of the Alberta Irrigation Technology Centre and the Brooks greenhouse from the Government of Alberta’s Ministry of Agriculture and Forestry to the college’s Centre for Applied Research, Innovation and Entrepreneurship (CARIE) will give researchers like Karimi more opportunities to expand their knowledge and apply it to a southern Alberta context.

“It would be great to be able to better quantify exactly how much water we can save, how much we can increase the yield for different crops like winter wheat or canola and the best time to apply fertilizer,” says Karimi. “Longer term experiments across multiple crops would also help with adoption of SDI technology in southern Alberta.”

The Mueller Irrigation Science program was made possible by a record-setting $3.1 million gift from Lloyd and Dorothy Mueller, announced in 2014 with an additional $1.9 million in funding from the College. Dr. Willemijn Appels, the Mueller Applied Research Chair in Irrigation Science, is the first fully-funded applied research chair in the college’s history and leads a team that investigates how new scientific findings can be translated into practical applications for producers in the irrigated agriculture sector of southern Alberta.

Lethbridge College’s Centre for Applied Research, Innovation and Entrepreneurship is a catalyst for economic growth, sustainability and social development in the region. It brings together researchers, community organizations and students to collaborate on projects that use new or existing knowledge to solve real-world challenges with immediate practical applications. Lethbridge College has been recognized as one of Canada’s fastest-growing research colleges while earning its highest ever placement in 2020’s annual ranking of Canada’s top 50 research colleges. The college placed 26th on the top 50 list released by Research Infosource and ranked third in research income growth.

<p>Dr. Rezvan Karimi Dehkordi, is the research associate on the Mueller Applied Research in Irrigation Science team.</p>