Every year, Quebec’s farm animals produce enough manure to fill a freight train reaching from Montreal to Vancouver and back. Quebec’s roughly nine million people excrete an estimated 5,400 tonnes of phosphorus a year. Measured in phosphorus, Quebec’s farm animals are the equivalent of a human population of about 42 million people: roughly four and a half times the number of actual Quebecers. Inside that tonnage sit roughly 135,000 tonnes of nitrogen and 58,000 tonnes of phosphate. This is why phosphorus, not nitrogen, is the pollutant that defines Quebec’s manure problem — and why the province chose to regulate it.