Floating beds in Banaripara, Bangladesh. © Haseeb Md. Irfanullah

Floating gardens

What is floating agriculture?

About 50% of Bangladesh is categorized as wetlands, mostly rivers and floodplains. Floating agriculture is a traditional agricultural practice of Bangladesh, which uses plant materials to make floating rafts in waterlogged areas to raise seedlings and grow vegetables in monsoon months.

Where is it practiced?

This age-old agro-practice was originated in the south-central wetlands of Bangladesh, namely in Barisal, Gopalganj, Madaripur, and Pirojpur districts. Since around 2000, this indigenous system has been extensively promoted by many NGOs and Government of Bangladesh’s agencies, particularly in the southern (above districts and Jessor), northern (e.g. Gaibandha, Nilphamari, and Rangpur districts), and north-eastern (e.g. Kishorganj, Hobiganj, Netrokona, and Sunamganj districts) wetlands of Bangladesh.

In what habitats is it practiced?

Coastal freshwater wetlands, norther riverine floodplains, and north-eastern wetlands (called haor).

What does it involve?

In this agro-technique, water hyacinth (an invasive species in Bangladesh) and other plant materials are used to build rafts on stagnant, shallow waters. Once rotten, various kinds of seedlings are raised and vegetables and spices are grown on the surface of these floating beds in monsoon months. In recent years, different innovations have been tested in different wetlands without using water hyacinth, but artificial structures.

What are the intended benefits?

By providing extra “piece of land”, this environment-friendly technique allows agriculture when all arable land of an area is under water. By raising seedlings on these beds during monsoon, farmers can start cropping on land as soon as floodwater recedes, without losing any more time. In addition, over the last 15 years or so, this technology has been widely discussed as an adaptation technology as climate change models predict more rain and longer, frequent floods in this part of the world.

What are the additional benefits?

Since 2000, floating agriculture has been promoted extensively by many NGOs and government agencies not only as a means of adaptation, but also of disaster risk reduction, livelihood option, nutritional security, and extreme poverty alleviation. This practice has reduced pollution as it uses less or no agro-chemicals.

What are the knowledge gaps?

Present and future benefits and effectiveness of water hyacinth-based traditional floating agriculture under changing climate to avoid potential maladaptation. Opportunities for alternatives, like aqua-geoponics—where aquaculture and floating gardening are combined and potential for its scaling up. Under changing climate, technological innovation is needed to make floating agriculture more resilient as a nature-based solution.

Is it ready to go to scale?

Scaling up of floating gardening is taking place since 2000 by NGOs and agencies of the Government of Bangladesh. Such scaling up has been essentially been project dependent. Climate variability hampers water hyacinth availability and accessibility in wetlands; it also affects seedling and vegetable growth. Water hyacinth cannot even tolerate moderate salinity, so salinity intrusion affects water-hyacinth-based floating agriculture on the coast. Younger generations seem to be moving out of the profession in its centre of origin. When introduced in new areas, absence of appropriate business model is a major challenge for its sustenance.

Policy pointers?

Floating agriculture exemplifies how an age-old natural-resource-based solution can offer new dimensions to fight societal challenges, like climate change, food security, and human socio-economic development. In 2015, the FAO declared Gopalganj, Pirojpur and Barisal in south-central Bangladesh as one of the ‘Globally Important Agricultural Heritage Systems’ (GIAHS), the first in Bangladesh. Floating agriculture has been discussed in the Fifth Assessment Report (2014) of the IPCCC. It has been showcased as an adaptation technology by the Technology Executive Committee of the UNFCCC.

How much does it cost?

Floating agriculture shows wide range of benefit cost ratio (BCR) in different regions. In Pirojpur district, for example, the BCR was calculated 1.43 (Kabir et al., 2019). In haor region, on the other hand, NGO-facilitated floating agriculture practice had BCR around 2.7, with a range of 0.9−3.7 (Pavel et al., 2014).