Paddy Cultivation during Early Holocene:Evidence from Diatoms in Lahuradewa Lake Sediments, Ganga Plain

Lahuradewa lake deposits, adjacent to the Lahuradewa archaeological site were rich in diatoms, going back to about 10 kyrs. The diatoms are grouped into four categories, namely, planktic, benthic, paddy field and anthropogenic-influenced. The variation in planktic and benthic forms reflects changes in the water budget of the lake in response to the change in rainfall, viz. more planktic in humid phases and less planktic in dry phases. These changes correspond to the changes identified by other proxies, namely phytolith. Paddy field diatoms are present in good numbers since about 8 ka along with anthropogenic diatoms; their numbers increase during dry phases and decrease in humid phases. This supports the contention that humans were living in this area since early Holocene and agriculture activity started around 8 ka. Presence of paddy field diatoms in lake sediments is rather unique. It is argued that the lake margin was used for paddy cultivation. Intermittently, sediment and organic remains namely paddy field diatoms, rice phytoliths and grass microcharcoal were washed from lake margin agricultural fields into deeper parts of the lake to be preserved in lake sediments.