“We need researchers and practitioners to work together to develop and demonstrate practical BMPs.”
– Don Flaten
Does off-stream watering of cattle and the use of vegetative buffer strips actually help improve water quality in Manitoba?
Preliminary answers to those questions were revealed at the MCDA annual convention in early December, based on studies of water quality best management practices undertaken by conservation districts, University of Manitoba and a number of other organizations at a cost of $300,000.
Armand Belanger, manager of East Interlake C. D., looked at the effectiveness of five-metre vegetative buffer strips for filtering out nutrients and preventing them from being washed into streams.
Collection tubes and double weirs were installed in the fall of 2008 so that water samples could be gathered the following spring, and grass clippings were harvested from the strips in June and September to simulate a hay harvest.
Soil test samples were also taken to get a picture of soil quality and nutrient levels.
Vegetation was also removed in late fall to look at the effectiveness of mowing as a means of removing nutrients trapped in buffer strips.
Describing the results gleaned from sites in Gimli, Manitou and Oak River, as “very preliminary,” he found that buffer strips were clearly effective in reducing sediments in run-off water.
In water samples taken between the two weirs at all sites last year, nutrient levels were reduced 47 per cent of the time in Gimli, 51 per cent at Oak River, and 39 per cent in Manitou.
“Our initial results are suggestive to previous studies,” said Belanger, adding that a more comprehensive examination
of the data comparing spring to summer run-off, and harvested and unharvested buffer strips, will come out over the next two years.
In introducing her study’s results, Barb Kingdon, manager of Assiniboine Hills C. D., noted that in some riparian areas – particularly meandering streams – cattle can’t be fenced out of the waterway by any practical means.
“Possibly, the answer to this
question would be, maybe you don’t (need to fence them out),” she said.
With the goal of testing whether or not offering an off-stream watering source would reduce the time cattle spend in and around water, three models were looked at: trough with natural barriers such as fallen trees, trough only, and a control group with no trough.
At the test sites near Souris and Killarney, seven cows in the first two paddocks were fitted with GPS tracking collars, and students did visual monitoring to record what the cows were doing.
Problems with beavers sabotaging the pump intakes threatened to scuttle the study, Kingdon said, adding that two more years of study are hoped to provide a clearer picture.
Don Flaten, a University of Manitoba soil scientist in the faculty of agriculture and food science, noted that while BMP tools developed using data from other locales are commonly touted as realistic solutions, very little research on their effects under the unique conditions found in Manitoba has been done.
The landscape here is flat, and the run-off is mainly snowmelt, not rain, he added.
That means the phosphorus (P) loading that results is mainly that of dissolved P that emanates from plant tissues exposed to the harsh freeze-thaw cycle of the Manitoba climate, not the erosion of soil particles as would be the case in hilly areas.
“We need researchers and practitioners to work together to develop and demonstrate practical BMPs,” he said.
“We need scientists to ensure that our BMPs are scientifically sound and environmentally effective, and we need people on the front lines like the C. D. s to make sure that the practices are technically feasible and economically affordable for producers.” [email protected]