Phosphorous in our waterways and buffer strips along the edge of fields

On Wednesday, this last week the Minister of Conservation, the Hon Stan Struthers annouced his plan to reduce phosphorous flowing into Manitoba Waterways.

A central part of this plan was the following "Starting in 2009, every farmer, homeowner, groundskeeper and municipality with land next to water will not be allowed to apply fertilizer in buffer zones."

In an earlier blog http://www.manitobaliberals.ca/2006/11/karin-wittenberg-and-national-centre.html , I commented that the province needs to be careful in setting phosphorous regulations, and making claims for their effectiveness because it is important to ensure that the regulations build on strong research showing that the regulations will have the desired effect.

What is very clear to anyone who travels outside of Winnipeg in southern Manitoba is that the large majority of water running off fields does not run off the field through a buffer strip, it runs off through a drainage channel (see photos above - the snow is in the drainage channels - the trees are planted on the buffer strip). Thus, building up buffer strips, and reducing the phosphorous applied to buffer strips will not affect the vast majority of phosphorous run-off from the field. Indeed, recent research by Steve Sheppard and Jeff Long which was reported at a recent Water Conference showed on average a 4% reduction in phosphorous with buffer strips.

If the agricultural run-off from cultivated fields in Manitoba is responsible for 10% of the phosphorous which enters Lake Winnipeg, then a 4% reduction in this 10% is an overall reduction of 0.4% of the phosphorous entering Lake Winnipeg. Ten percent of phosphorous derived from cultivated fields is reasonable, given that the total phosphorous contribution from Manitoba agriculture (including feedlots, hog lagoons, fields which are not cultivated) is at 14%. (See the Lake Winnipeg Stewardship Board Interim Report, February 2005 )

I am not necessarily saying do not take these measures with respect to buffer strips, but I am saying, let us put this in perspective. The overall effect of one of the major measures to be implemented by the NDP is small in the context of the reduction in phosphorous that needs to be achieved. In other words, let no one be fooled, the NDP in their announcement are attempting to promote the illusion of having a major effect, rather than actually achieving a major effect (and note the NDP action will not even start until 2009).

Indeed, this reduction is much less than the phosphorous reduction which can be achieved by elminating phosphorous in dishwasher detergent in Manitoba (overall a 2% reduction in the phosphorous going into Lake Winnipeg). We have recommended that the latter step be taken as soon as possible, and indeed will be introducing legislation this fall to achieve this.