Night soil contains

Night soil is nothing but Human excreta, collected from cesspools, privies, pail closets, pit latrines, and septic tanks. It was produced as a result of a sanitation system in areas without sewer systems or septic tanks and sold as a fertilizer.
Night soil is very rich in essential plant nutrients. It contains about 5.5% Nitrogen, along with other compounds like phosphorus, potassium, etc.