by Lucas Habib

Strips of vegetation along stream banks have long been recommended to protect watercourses from sediment and chemicals carried by cropland runoff, but University of Guelph researchers now want to apply this principle to runoff from cattle manure as well.

Professors Ramesh Rudra and Hugh Whiteley, School of Engineering, are working with Professor Mike Goss, Land Resource Science, to test different grasses and strip widths to determine which combination works best for removing the pathogens - disease-causing organisms - found in manure.

Once the project is completed, cattle farmers could have a simple and economical way to reduce the impact their animals have on water systems and reduce the risk of disease in the process.

"Planting a strip of grass a few metres wide along the edge of a stream on a farmer’s property can be enough to prevent contamination from manure," says Rudra. "For this experiment, we want to simulate manure without actually using deadly organisms."

The primary toxic "bugs" in cattle manure are the microscopic parasite Cryptosporidium and bacteria such as E. coli. Nitrogen and phosphorus are also of concern. Previous research has shown that even short grass strips can significantly improve the quality of runoff by filtering out hazardous constituents associated with sediment. Now the best combination of factors for various conditions on different farms needs to be determined.

For the experiment, different grasses will be planted on sloped land, and the widths of the grass strips will vary. During the first part of the experiment, the research team will use artificial manure containing charged microspheres to represent the pathogens. Microspheres are tiny beads modelled to the same size as the pathogen being studied and equipped with the same electrical charge. They act similarly to the pathogens as they move through the vegetation plots.

After being mixed with water to simulate runoff from rain, the artificial manure will be filtered through the grasses at varying rates. At the bottom, liquid will be collected and examined for the presence of microspheres to see how much of each simulated toxin has entered the receiving water.

Also assisting with the project are Ken Carey of the Guelph Turfgrass Institute and post-doctoral student Bahram Gharabaghi.

Funding for this research has been provided by the Ontario Cattlemen’s Association, the Ontario Ministry of Agriculture, Food and Rural Affairs, and the Natural Sciences and Engineering Research Council.