Category Archives: Field work

275 Samples and 276 Mosquito Bites

–by Thanuja Thavarasa

Living organisms need a variety of nutrients in order to grow. For plants, nitrogen is an essential nutrient. Nitrogen, found in the form of nitrate (NO₃ˉ), is taken up through plant roots from the surrounding soil. Thus, we thought it would be interesting to explore the relationships between soil nitrate concentrations and the plant nitrate levels in a riparian area adjacent to the Speed river, right in the middle of the city of Guelph.

On June 12th and 13th, 2019, Aidan and I headed to our site where we measured and created our own 16 m by 30 m sampling grid that extended from the edge of the river to a walking trail. In Figure 1, every interval along the X-coordinate and Y-coordinate axes is two meters, and the apices of the grid correspond to where a soil sample and, when available, a plant sample, were taken. Figure 1 and Table 1 show were we collected 144 soil samples and 131 plant samples.

After collecting all the samples, we returned to the lab to analyze their nitrate concentrations. The soil was passed through a 2 mm sieve and then 5 g of sieved soil was mixed with 25 mL of tap water. Once the mixture set for 5 minutes, a disposable pipette was used to extract liquid from the top of the mixture and then transferred to the Laqua Twin nitrate sensor. Similarly, once sap was extracted from plant samples using a garlic press, the sap was put into the sensor to be analyzed. Figure 2 illustrates plant to soil nitrate ratios with context to their location. Further analysis of the data is in the works. Keep an eye out for Aidan and I at a potential future conference!

URA fieldwork project: nutrient concentrations in select rivers and wetlands in Guelph, ON

— by Aidan Doak, on behalf of myself and Thanuja Thavarasa

On May 8th, 2019, Thanuja and I kicked off our summer undergraduate research assistant (URA) positions at the University of Guelph. There were many potential projects planned for the months to come and a water chemistry analysis project was at the top of our list. The goal was to observe and compare any relationships between nitrate and phosphate concentrations in different water systems within the Grand River Watershed. The city of Guelph, located right in our backyard, became our primary focus. We collected water samples from six sites after significant rainfall events.  We have provided a map showing our six site locations below (Figure 1) and a table displaying sampling dates and precipitation totals since the previous outing (Table 1).

Samples were tested for electrical conductivity and oxygen reduction potential in the field. Afterwards, they were brought back to the lab for turbidity measurements, filtration and analysis of nitrate and phosphate concentrations. We have compiled our data and graphed some of our results below. The straight blue line in each figure highlights the 0.03 mg/L provincial water quality standard for phosphate.

The Eramosa River and the Speed River were our two river sites, with relatively wide channels (Figure 2A and 2B). Both sites demonstrate a similar nutrient behavior; consistently higher concentrations of nitrates compared to the wetland sites (Figure 3), and phosphate concentrations that vary over time more compared to wetland sites. Phosphate concentrations fluctuate within 0.03 mg/L of the provincial water quality standard. The known, higher mobility of nitrate compared to phosphate could explain this behavior. The high levels of nitrate are potentially a product of recent rainfall events, washing nitrates downstream.

A riparian wetland located next to the Speed River was sampled at two locations; the first was closest to the river and the second was adjacent to a walking trail (Figure 3A and 3B). The wetland experienced many expansions and contractions throughout the two-month sampling period. On May 21st, there was no surface water at the Speed River Wetland Trail location so we could not take a sample. The Speed River Wetland Trail location experienced phosphate concentrations three times larger than the provincial standard, while the adjacent Speed River Wetland location had a phosphate concentration that was ten-fold the same standard. The ability of soils to retain phosphate, paired with the expansion and contraction characteristics of the wetland adjacent to the Speed River, may explain those dynamics. Wetlands are nutrient sinks as they prevent nutrients from reaching rivers and streams, which is an environmental benefit.

The Solstice Wetland (Figure 3D) exhibited a different relationship between phosphate and nitrate concentrations compared to the other river and wetland sites. The Solstice Wetland behaved as a perennial wetland as it always had surface water in the depression during the two-month sampling period. On the other hand, the Speed River Wetland is intermittent: it expanded and contracted to the extent that no surface water was present on multiple sampling days. At the Solstice Wetland site, nitrate and phosphate concentrations were strongly correlated, as indicted by their synchronous increasing and decreasing behaviors.



If you were wondering why the Dairy Bush was blue… It was us.

— by Thanuja Thavarasa, on behalf of myself, Aidan Doak and Jamie Bain

Water flow through soil is quite complex. It can move either vertically or horizontally dependent on a variety of factors like soil texture and different types of rainfall events. It can be valuable to know these water flow patterns since they can be used, for instance, to track and regulate the movement of harmful nutrients (like phosphate) to rivers and lakes.

Here is a quick video that shows our work in the field from our own perspective.

At the University of Guelph, the Dairy Bush is divided into two adjacent sectors: a forested area and a grassland area. After scouting the location, we thought it would be interesting to compare and contrast water flow patterns between these two land covers. Thus, on June 3rd, 2019, Genevieve, Aidan, Jamie and I set out to prepare two 1 m by 1 m plots. The idea behind this project was to evenly spread 30 L of water across the plot. The water was dyed with an environmentally friendly blue dye prior to the experiment. After a couple of days, the goal was to excavate these plots and visualize soil water flow patterns via the blue soil stains left behind by the blue water. We ran into a water application problem on the grassland plot due to tall shoots and strong winds. Fortunately, we were still able to successfully saturate the plot with the 30 L of water.



Testing the “two-water-worlds” hypothesis in southern Manitoba ~ by Janelle Laing

During the 2015 field season, members of our research group conducted a study on the Fort Garry campus of the University of Manitoba; the study aimed to test the “two water-worlds” hypothesis, which suggests that plants preferentially access tightly-bound soil water over mobile soil water. We collected rainwater, streamwater, mobile soil water (using suction lysimeters), bulk soil, and mature tree and shrub twigs. All samples were then tested for stable water isotopes to compare the isotopic signature of the different water types, assuming that clustered water types originate from the same source.

Here is a video summarizing one day of sampling:

What is the relative importance of soil water versus bedrock groundwater?

While most of Prairies are relatively flat, the Pembina escarpment (also called Manitoba escarpment) is a striking topographic feature responsible for the presence of few steep-sloped landscapes in Manitoba. Because the escarpment is associated with the presence of different shale units and bedrock fractures, however, its impact on regional hydrology is probably much more complex than we think. To start tackling that mystery, Adrienne Schmall and Cody Ross set up a new project southwest of Miami, MB in the South Tobacco Creek Watershed. Adrienne will notably study water infiltration through soil and shale units just above the Pembina escarpment, and she will use both geological mapping and stable water isotopes to help her do that. Adrienne’s very first step was to do a little bit of plumbing to capture water seeping out of soil horizons and shale units, and that first step was completed in the past few days. See pictures below!


Soil horizons and shale units exposed in the South Tobacco Creek Watershed


Close-up view of PVC pipes and flexible tubing routing water from soil horizons (or shale units) to collection bottles

2015 MCDA Tour hosted by the Lasalle Redboine CD

As part of Laura Blunden’s summer experience with the Watershed Systems Research Program (WSRP), she played an instrumental role in partnering with various stakeholders and was fortunate to attend the Manitoba Conservation District Association’s (MCDA) tour. The tour was held on June 16, 2015 by the LaSalle Redboine Conservation District for the Pelly’s Lake watershed management project. During the tour, conservation and municipal officials opened the culvert gates that released water held from spring melt at Pelly’s Lake. The LaSalle Redboine Conservation District built the Pelly’s Lake dam last year in collaboration with many landowners who donated portions of their property for the project. This initiative allows the valley to back flood and mimic how the water would naturally flow over the landscape over time. The slower flow reduces flooding, improves habitat protection, and allows for cattails to take up the phosphorous from the water. The water is held in Pelly’s Lake wetland as part of a water management strategy in which every year approximately 5,000 kg of phosphorous are prevented from draining into Lake Winnipeg through the use of cattails. The International Institute for Sustainable Development (IISD) performed a cattail harvesting demonstration during the tour where participants learned about the uses of harvested cattails, including transforming them into biofuels and soil amendment products; meaning farmers no longer have to import soil amendment products from such long distances. CTV was present on site to conduct a news report of the event, which can be seen here:

Tour visiting Pelly's Lake Dam

Tour visiting Pelly’s Lake Dam

Pelly's Lake Dam

Pelly’s Lake Dam

Justin Reid and Colby Desender from LaSalle Redboine Conservation District

Justin Reid and Colby Desender from LaSalle Redboine Conservation District

Quick recap of the 2015 MSSS Tour

On June 18, 2015, Laura Blunden attended the Manitoba Soil Science Society (MSSS) tour with the University of Manitoba Watershed Systems Research Program (WSRP). The tour stopped at the Classen Farm, which is currently being studied by Ph.D. student Kokulan Vivekananthan and other researchers from the University of Manitoba and the University of Waterloo to see the effects of tile drainage and water retention on runoff and nutrient export from agricultural fields. For more information on the Classen Farm research you can download the pdf brochure: Classen Brochure Final_ReducedSize.

Colby Desender from the LaSalle Redboine Conservation District discussed the engineering of the water retention pond, while David Lobb and Kokulan Vivekananthan talked about the science behind the research, and farmer Carl Classen discussed the benefits of enhanced water drainage for his field. Some benefits include reduced flooding, healthier crops and less runoff of nutrients. Mitchell Timmerman from MAFRD (Manitoba Agriculture, Food and Rural Development) is a pedologist who was also at the tour and illustrated the impact of nutrient management in soils using a rainfall simulator. A short YouTube video is also available to see what type of research is conducted at the Classen Farm: