https://www.sciencedaily.com/releases/2022/02/220207083438.htm

Significant levels of fertilisation

Researchers at Ghent University have estimated that each year dog faeces and urine add an average of 11kg of nitrogen and 5kg of phosphorus per hectare to nature reserves near the Belgian city of Ghent. The researchers say that the nutrients added through this neglected form of fertilisation are substantial and could be detrimental to biodiversity and ecosystem functioning.