A city’s waste became a farm input
Edo’s dense population produced a steady supply of human waste, while the surrounding farms needed nutrients to keep crops growing. With relatively few large livestock, farmers could not rely on cattle or horses for enough manure. The contents of household privies—often called night soil—offered another source of fertilizer.
The material was collected from the city and carried to fields, where its nutrients helped replenish the soil. What might otherwise have been a costly sanitation problem therefore had agricultural value: removing waste from crowded homes also supplied something farmers wanted.
A privy could have an owner
That value changed the economics of renting. If a landlord’s building had a privy, the waste accumulating there was not simply something tenants discarded. It could be treated as an asset, and some rental agreements included the night soil as part of what the landlord received.
In effect, a lease could assign rights not only to the rooms and land but also to a useful material produced by the people living there. The arrangement made practical sense when farmers would pay or trade for fertilizer and landlords had access to a regular supply.
The city and countryside were linked
This trade connected urban life to food production: nutrients consumed in the city could be carried back to the fields that grew crops. It also meant that control over a shared privy had economic consequences, not just hygienic ones. In Edo, even what accumulated beneath a rental house could help determine the value of the property.
