LAKE LOUISE, Alta. – Alberta is attempting to ensure it avoids the kind of ecological damage linked to nitrogen oversaturation in Europe.
Conclusions from a 2001 nitrogen assessment survey determined about 120,000 tonnes of ammonia per year are released into the atmosphere from a variety of sources.
“The conclusion was that agriculture produces about 90 percent of the total ammonia emissions in the province so that is quite a substantial thing to identify,” said Len Kryzanowski of Alberta Agriculture.
However, ammonia is just one source of nitrogen. Other forms of nitrogen are derived from industrial sources such as fuel burning emissions.
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Most ammonia emissions came from livestock production, either from animals or manure spreading. About a third came from fertilizer applications when urea is applied to soil and converted to ammonia. The remaining 10 percent is released from vehicles and other industries.
“There is some opportunity to reduce and capture some of that ammonia emission, whether it is in fertilizer or livestock production,” Kryzanowski said.
The province expects to conduct another survey within the next year. The new survey will follow similar formulas used in Europe to measure critical loads, which are the highest annual inputs of a nutrient that does not cause unacceptable ecological or human effects.
Alberta’s Agriculture Operations Practices Act recommends manure injection into the soil so plants get the full benefit rather than losing nitrogen gas into the atmosphere.
Up to 40 percent of nitrogen is lost when manure is spread on open fields.
Allowable levels of soil nitrogen could change if policy makers follow recommendations from a seven-year study of phosphorus overload in the province.
The 2001 report and its recommendations are under review, said Barry Olson of Alberta Agriculture.
If the recommendations are followed, manure management regulations could be changed to state how much phosphorus the soil can handle and recommend the application of an inorganic supplement if more nitrogen is required.
The study found most Alberta soil needs nitrogen and phosphorus, but when it is delivered in the form of manure, the two are not balanced for optimum plant growth.
“If you can control the phosphorus, nitrogen should not be a problem,” said Olson.
Compared to other regions with heavier precipitation, semi-arid areas, such as southern Alberta with its high concentration of livestock, experience little runoff. Nutrients leaching into the environment are not as serious as in coastal regions or parts of Europe.
Efforts are underway in Europe to reduce nitrogen and phosphorus levels using scientific data and expert judgment on acceptable loads, said Chris Evans of the Centre for Ecology and Hydrology in Bangor, Wales.
Too much nitrogen can destroy biodiversity and encourage the growth of unwanted plants, he told a nitrogen conference Sept. 29 in Lake Louise sponsored by the Clean Air Strategic Alliance.
“The point is we don’t kill the plants, we just get other plants coming in,” he added.
“Eventually they will potentially reduce the abundance of the others or they might completely out-compete them and they’ll disappear altogether and we’ll get a changed ecosystem.”
