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Traditional floating garden practices for vegetable production in Bangladesh
Floating garden practice is a local indigenous production system most successful in the wetland/submerged/flooded areas of selected south and south-western districts (Pirojpur, Barisal and Gopalganj) of Bangladesh. These areas remain submerged for long periods, especially in the monsoon season. Floating garden agricultural practices have been adopted by local farmers for nearly two centuries. They floating garden practices are developed based on farmers’ indigenous knowledge and experiences. The farming technology provides an opportunity for the poor communities to produce crops (particularly vegetables and spices) during Monsoon season when many wetlands are submerged under water (generally for 6-8 months of the year).
One type of floating beds for floating garden agricultural practices is used as an alternative method for crop production (particularly vegetables and spices) during monsoon, when most of the land is flooded. During this period (mainly June-October) farmers cultivate okra, red amaranth, cucumber, Indian spinach, turmeric, aroid on organic floating beds made of water hyacinth.
Another type of floating beds for floating garden agriculture practices is used mainly for seedling production of different vegetable and spice crops. For a detailed description of the practice for seedling production please refer to http://teca.fao.org/read/8869.
2.1. Construction of floating bed for crop production
Farmers generally collect water hyacinth (Eichhornia crassipes) from the nearby wetland/ submerged areas to prepare floating beds directly on water (water depth 1 meter or more). Traditionally, the floating bed is constructed with 3-5 layers of water hyacinth arranged step by step from the bottom to the top until attaining the desirable height of the bed.
During bed preparation, the root of water hyacinth is arranged at the side and the shoot is placed in the middle position of the floating bed. The water hyacinth layer is made at 5-7 days intervals. Water hyacinth is drawn with the help of wooden hook placed on bamboo made handles (locally named as “Thora”) (Figs. 1-2). After preparing several layers, the floating bed becomes compact due to decomposition of the water hyacinths. The immature water hyacinth decomposes earlier than the mature ones. Therefore, the mature water hyacinth layer is generally used as foundation and the comparatively, the immature ones, are kept at the top of the floating bed.
There is no recommended size or shape of the traditional floating bed (Fig. 3). It is generally 15-20 meter long, 1.3-1.8 meter wide and 1.2-1.3 meter high. The size of the floating bed depends on the water space on which the bed is placed for crop production.
The prepared floating bed is anchored with bamboo and rope so that it cannot be displaced to other places or locations (Fig. 4). In the recent years, the floating bed is also sold in ready-made condition at the local floating market. Generally, male farmers are engaged with the preparation of floating bed.
2.2. Preparation of ball for seedling raising
Farmers prepare special balls for seedling raising (Fig. 5). The ball (6-8 cm diameter) is made with well decomposed water hyacinth (Fig. 6) for raising seedling of selected vegetable crops (Indian spinach, okra, cucumber, morma etc.). The organic ball is locally termed as “Tema” or “Mada”. The tema/mada is used as growing media of the seedlings.
2.3. Seed placement and seedling raising into the ball/tema/mada
At first, three to four holes are made into the ball/tema/mada with the help of pointed stick or the thumb (Fig. 7). Then 3-4 seeds were inserted into the hole for germination. Generally, local varieties of crops are used for crop production. After germination of the seeds (5-7 days after seed placement), the seedling balls are kept under light shadow condition at homestead area for hardening and to increase their adaptation capacity. The young seedlings are watered daily for keeping the growing media or ball at optimum moisture condition. The seedlings are also protected from any kind of damage through fencing surrounding the homestead nursery (Fig. 8). The seedlings are shifted to the water field when they become suitable for transplanting on the main floating bed (Fig. 9). Generally the seedlings become suitable for transplantation at 10-15 days after germination of vegetable seeds.
2.4. Seed sowing or transplanting of seedlings on floating bed
The floating bed becomes suitable for sowing/planting of crops after 20-25 days of preparation. Some farmers apply urea fertilizer (about 400-500g/10m2) on the floating bed to enhance the decomposition and in order to sow or plant earlier.
Traditionally, seeds of leafy vegetables like red amaranth are sown directly through broadcasting on floating bed (Fig. 10). Seedlings of other selected vegetables (Indian spinach, okra, cucumber, morma etc.) (Fig. 11) are transplanted in row in the afternoon. Turmeric, sprouted rhizome and sucker of aroids, the crops are transplanted in row, too (Fig. 12). During transplanting, the seedling balls as well as sprouted rhizome and lower portions of sucker are covered with decomposed water hyacinth in order to establish them on the floating bed successfully.
2.5. Intercultural operations and protection of crops on floating bed
There are no recommendations for fertilizer management packages for cultivating crops on floating beds. If plants become yellowish, the farmers usually apply urea fertilizer as top/side dressing only followed by irrigation for enhancing the vegetative growth of the cultivated crops.
Irrigation and weeding are done as per requirement of the crops for their proper growth and development (Fig. 13). In some cases, the crops are given fencing by nylon net to protect from the attack of duck (Fig. 14). Sometimes, the floating bed crops are damaged by rat. Farmers use indigenous method to protect the crop from the infestation of rat (Fig. 15).
2.6. Harvest of crops on floating bed
Farmers harvest the crops when they attain the harvestable stage on the floating beds. The field duration of the crops depend on their harvestable stage as well as maturity. The crop products (vegetables and spices) are generally used for consumption by the farm households. Besides, farmers sell a surplus amount of their agro-products to the nearby people as well as at local markets to earn some extra cash for meting up their daily household expenses. Below are shown some examples of crops ready for harvesting.
2.7. Profitability of crop production on floating bed
The farmers earn an average profitability of USD 140 per 100 square meter of floating bed from crop production during a monsoon season.
3. Advantages of the systems
Floating agriculture practices have minimal infrastructure and very little capital requirement. Costs can also be kept low because raw materials for the construction of floating beds are readily available from local waterways. Materials for floating beds are affluent. In particular, water hyacinth is usually classified as one of the worst invasive species. For that reason, farmers can easily use it as floating bed or composts without any additional cost. This gives the opportunity to many people living in this area to cultivate using this technique.
In fact, this system considerably mitigates the risks of natural disaster and climate change and the productivity of floating vegetable cultivation is estimated ten times higher than on a similar sized land-based cultivation. Given that it allows better control over crops, some researchers have noted a greater productivity of floating bed practices compared with traditional land-based agriculture.
Moreover, the use of chemical fertilizers and pesticides is minimal in this system. The beds can also be recycled and used as organic fertilizer in the newly prepared floating bed and agricultural fields. This is both economic and environmentally friendly.
Using water hyacinths reduces breeding grounds for mosquitoes. It also participates to a better carrying capacity of water circulation by reducing the weed breaking down the drainage system. With a better water circulation and less invasive weeds, this system has a positive impact on open-water fishing.
The practice also contributes to food security as follows:
- Additional space for vegetables cultivation in the wetlands;
- Increase in vegetables supply in the area and the surroundings;
- Primary nutrients (e.g. nitrogen, phosphorus and potassium) and micronutrients (e.g. boron, molybdenum etc.) are available in water hyacinth, comparable with cow-dung and other organic manures;
- When water recedes in wetlands, dismantled floating platforms are used as organic fertilizer. In this way it enhances eco-friendly agriculture practice in winter seasons to cultivate winter crops.
The following video shows how school children in Bangladesh learn about how floating garden practices can contribute to food security. Global Food Security: How can we feed a growing population? (This video is produced by from British Council Schools Online and available on Vimeo).
For further advantages of the practice please refer to: http://teca.fao.org/read/8869
For a detailed description about improvements of the traditional practice based on research programmes please refer to: http://teca.fao.org/read/8868.
The following video gives a short introduction about traditional floating garden practice and its improvements developed by BARI: https://www.youtube.com/watch?list=UU6bZ-oCK06YzlRLwrEhVsYw&v=ktzkGqvWnUE
The pictures used in this document has kindly been provided by the Bangladesh Agricultural Research Institute (BARI).
The system for seedling production is traditionally practiced in the wetland/submerged/flooded areas of selected south and south-western districts (Pirojpur, Barisal and Gopalganj) of Bangladesh.
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Globally Important Agricultural Heritage Systems (GIAHS)
BARI (Bangladesh Agricultural Research Institute) is the largest multi-crop research institute in Bangladesh conducting research on a wide variety of crops, such as cereals, tubers, pulses, oilseeds, vegetables, fruits, spices, flowers, etc.
Besides variety development, BARI carries out research on areas such as soil and crop management, disease and insect management, water management and irrigation, development of farm machinery, improvement of cropping and farming system management, post-harvest handling and processing, and socio-economic studies related to production, processing, marketing and consumption.
Over centuries, generations of farmers, fisher folks and herders have developed complex, diverse and locally adapted agricultural systems with time-tested technologies. These systems have not only provided multiple goods and services for rural communities, but also created, maintained and inherited remarkable knowledge, outstanding rural landscapes, globally significant agricultural biodiversity and unique cultures. In 2002, FAO started an initiative for the conservation of Globally Important Agricultural Heritage Systems (GIAHS), in order to promote public understanding, awareness, national and international recognition of these systems.
The concept of GIAHS is distinct from, and more complex than, a conventional heritage site or protected area/landscape. It is rather a living, evolving system of human communities in an intricate relationship with their territory, cultural or agricultural landscape or biophysical and wider social environment. The humans and their livelihood activities have continually adapted to the potentials and constraints of the environment and also shaped the landscape and the biological environment to different degrees. The resilience of many GIAHS sites has been developed and adapted to cope with climatic variability and change, natural hazards, new technologies and changing social and political situations, so as to ensure food and livelihood security and alleviate risk.
By coping with challenges of today and tomorrow, GIAHS with its contribution to achieving UN SDGs is gaining positive momentum and upscaling worldwide.