Last week I posted a short series on my blog about the need (or lack
thereof) for nitrogen-fixing plants in small plots where the residents
recycle their urine into the garden. Based on Martin Crawford's figure of
one pee (half a litre) containing about 5.6 grams of nitrogen, and using
his numbers for nitrogen demand of different food forest canopy plants, I
calculated that one person's annual urine should meet the nitrogen needs
of 4100-5100 square feet of forest garden.