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Winnipeg Free Press - PRINT EDITION

Non-renewable phosphorus both a curse and a necessity

By: Laura Rance

Posted: 03/20/2010 1:00 AM | Comments: 0 (including replies)

We Canadians like to think of ourselves as a resource-rich nation. And it is true -- we are well-endowed with energy, water, land and minerals.

But there is one nutrient necessary to our well-being -- in fact our food security -- that we don't have in plentiful supply, and a new report from the International Institute for Sustainable Development (IISD) warns we are squandering what little of it we have.

That nutrient is phosphorus, a non-renewable resource essential to plant growth. The same phosphorus that is killing Lake Winnipeg through eutrophication.

So which is it -- precious or noxious? The IISD says our management of it makes it both.

"Phosphorus is an indispensable resource that has been mismanaged to the point that we are jeopardizing our long-term food and water security. We need not look any further than Lake Winnipeg to see the consequences of that," said the IISD's Vivek Voora, co-author of Peak Phosphorus: Opportunity in the Making -- Why the Phosphorus Challenge Presents a New Paradigm for Food Security and Water Quality in the Lake Winnipeg Basin.

Canada not only depends upon importing the resource. Its economy is partly driven by exporting it in the form of food.

Comparing it to "peak oil," the term applied to depleting petroleum reserves, the recently released report raises the looming reality of "peak phosphorus." It says a wholesale shift is required in how the nutrient is viewed across all sectors of society.

Annual world consumption has grown steadily from 28 million tonnes in the early '60s to 160 million tonnes today. The cost has been rising, too. In recent years, price shocks pushed phosphorus to $1,200 per tonne in 2008, a six-fold increase over what farmers paid in 2002. Although prices have since fallen to around $850 per tonne, experts say the shrinking global supplies mean it is unlikely to return to previous low levels.

Manitoba is second only to Saskatchewan as the region having the highest proportion of phosphorus-deficient soils in North America. An estimated 73 per cent of the land base here is low in phosphorus.

Yet in an odd quirk of nature, Prairie waterways are notoriously high in phosphorus because the freeze-thaw cycle of our annual spring snowmelt flushes it out of decaying plant material in a water-soluble form. In fact, the La Salle River, which starts at Portage la Prairie and meanders over to the Red River just south of Winnipeg, is referred to as "la Rivière Salé" on early maps. Translated, that means "stinking river."

Once phosphorus is lost to the sea, it takes millions of years for it to be mineralized back into a form that can be mined.

The report's authors are calling for a broadly based reassessment of policies and management strategies to prepare for phosphorus shortages. "Current practice in many industrialized countries is unsustainable in peak-phosphorus scenarios," the report says. "Changes must include substantial shifts in production and consumption patterns."

And they stress that while it is an issue with obvious implications for agriculture, it can't be addressed solved solely by what farmers do. "Responsibility must be shared by all stakeholders. This amounts to adopting a life-cycle, cradle-to-grave approach to phosphorus-based products, which include fertilizers, food and fibre."

That means cities, too, which for the purposes of nutrient management are intensive livestock operations on a grand scale. For example, phosphorus and ammonium can be recovered from waste water in the form of struvite, a magnesium-ammonium-phosphorus precipitate, which can then be converted into a slow-release fertilizer.

This technology could help Winnipeg recoup some of the billion or so dollars it's spending to upgrade its waste-water treatment. A struvite-recovery system would prevent waste-water return pipes from clogging and produce a substantial amount of fertilizer (potentially more than 500 tonnes a year), which could be sold to farmers.

Controlling food waste while recapturing phosphorus through composting, instead of bagging it and dumping it in landfills, is another phosphorus-recycling imperative. It is estimated up to 40 per cent of all food is wasted worldwide. "The world's hungry could be fed more than seven times over with food waste originating from Europe and the United States alone," the report says.

Many of the fruits and vegetables produced globally never reach the market simply because they fail to conform with sizing standards. "The underlying problem leading to food waste stems in part from consumer behaviours supported by an economic system built to produce more than we need."

The report, at www.iisd.org, is thought-provoking. It remains to be seen if governments can convert inertia into action.

Laura Rance is editor of the Manitoba Co-operator. She can be reached at 792-4382 or by email: laura@fbcpublishing.com.

Republished from the Winnipeg Free Press print edition March 20, 2010 B9

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