Tuesday, October 15, 2013

Phosphorous still pollutes Great Lakes


Farmers need to step up their efforts to reduce the volume of phosphorous eroding into streams, rivers and the Great Lakes, says Ontario Environment Commissioner Gord Miller.

He praises farmers for making good progress on phosphorous reduction during the 1970s and 1980s, but says now more needs to be done because algae blooms are once again marring the Great Lakes and starving fish of oxygen.

“If we have more biologically active soil, which means we adopt no-till systems, and we work with them for a longer period of time we increase the biological activity,” Miller writes in his annual report.
“The net result is reduced reliance on fertilizer to provide phosphorus.
 

“But farmers need the freedom to work out their own management systems that suit their operations in conjunction with continued access to good scientific advice, he says.
“We need that liberty in the equation. Self-directed ownership works, you just have to let it work.”
Miller says the phosphorus strategy would be similar to the province’s long-standing waste management strategy that promotes three Rs – reduce, reuse, recycle.
Ontario’s Nutrient Management program is aimed at limiting the amount of fertilizers, including phosphorous, that are applied to what’s needed to grow the crop in that field.
Ironically, one of the innovations that could reduce phosphorous being applied to land is the genetically-modified Enviropig developed at the University of Guelph, but shelved because obtaining government approvals has been too costly.
Dr. Peter Forsberg genetically modified pigs so they produce more phytase in their saliva and that, in turn, improves the pig’s ability to extract the phosphorous it needs for growth.
By improving the efficiency of phosphorous extraction, less phosphorous needs to be added to feed rations and less ends up in hog manure.
Phosphorous is the limiting factor for manure applications on hog farmers trying to stay within Nutrient Management Plan volumes.
Reducing tillage has also reduced the amount of soil that washes into streams, rivers and the Great Lakes. Phosphorous clings tightly to soil particles, but is released in water.
Little has been said about the increasing volume of phosphorous that is sequestered in fields where tillage and erosion has been reduced and whether or when that buildup of phosphorous will be released to waterways.
On the other hand, municipal sewage treatment systems remain a huge source of phosphorous draining into the Great Lakes. In Waterloo, for example, an equipment failure earlier this month resulted in more than 850,000 litres of untreated sewage spilling into the Grand River.