Almost no other measures have been taken to increase soil productivity. Available historical data suggest that Persian farmers and landowners have long been aware of the value of dung as fertilizer. On the outskirts of towns higher-quality manure was available from night soil and other sewage. Some mosques had very large public toilet facilities. Mountain villagers sell manure to agriculturalists on the plains in the spring, after the underground shelters in which the goats and sheep are housed during the winter have been cleaned.
Privy cleaners sell night soil the year round.
The situation in Afghanistan is not much different from that in Persia. Dung is used as a fertilizer in areas like eastern Afghanistan, where sufficient wood for fuel is still available in the mountains. Even there, however, dung is used for fuel in the lower valleys. Central Asia . I. Adams, Persia by a Persian , Washington, D.C., 1900.