Credited to Bangladesh. Soil-free cultivation on floating beds also exists at Dal Lake in Kashmir and Inle Lake in Myanmar. The Bangladeshi practice is a distinct, separately documented tradition recognized by the FAO.
How it began
In south-central Bangladesh people have used a method of cultivation called dhap, known locally as baira, for 300 to 400 years. It is most common in the districts of Gopalganj, Barisal and Pirojpur. The country lies on the flood plains of the Ganges and Brahmaputra, and large areas stay under water for as much as eight months a year, so farmers there built gardens that float.
How it works
During the monsoon farmers stack compact layers of water hyacinth, duckweed or rice stubble on still water and beat them into a raft. The plants are left to rot and are usually mixed with cow dung and silt. Seeds are started in small balls of peat soil wrapped in coconut fiber, and seedlings about 15 centimeters high are transplanted to the bed. Bamboo poles anchor the beds, which last five to six months and usually need no fertilizer.
What changed first
The beds rise with the water, so a family can grow okra, gourds, spinach, eggplant, turmeric and ginger through the flood season and sometimes raise rice seedlings. A bed costs about 8,000 taka. According to an FAO report cited by the BBC, farmers earn an average profit of 140 US dollars per 100 square meters of bed.
What lasted
An FAO study records that farmers used other aquatic plants until water hyacinth became prevalent in the late 1960s; since then it has been the main material for the beds. In December 2015 the Food and Agriculture Organization declared the floating gardens a Globally Important Agricultural Heritage System.
Where it stands today
Farmers are reviving the practice as monsoon flooding and waterlogging worsen with climate change. Development agencies such as Practical Action promote it as a low-cost way to keep producing food all year in areas where land crops fail. The BBC reported on farmers in Gopalganj who gave up flooded rice fields for floating beds.
