The coronavirus (Covid-19) pandemic continues to shatter and decelerate the world natural progressive systems. Different national strategies that have been adopted to mitigate Covid-19 outbreak have significantly invaded food production, demand and supply that eventually raise questions about food security during and after Covid-19 health crisis.
The World Bank policy note stated that, “this global pandemic may cause breaks in food supply chains, food shortages and food price spikes in Bangladesh and a broader range of countries”. So, what can we do to ensure the food security of Bangladesh and that is obviously in an environment friendly way? As population growing day by day in Bangladesh, the amount of cultivable land is constantly decreasing. Ponds, rivers, canals and reservoirs are being filled.
At the same time, due to environmental pollution and lack of safe water, when crop production and fish farming are not increasing as we desired, it has become exigent to use alternative methods to fulfill the desire. Aquaponics could be a great solution with regard to this food security issue that is growing in an alarming rate and might be hit severely after this pandemic situation decreased or gone.
Aquaponics is the dyad of aquaculture (fish raising process) and hydroponics (growing plants without soil) that grows plants and fish together in one integrated system without soil medium. Aquaponics uses a very easy recirculating process to grow and harvest crops and fish firm. With aquaponics it takes about a month to start the system by developing a colony of nitrifying bacteria through a process called ‘cycling’.
The ammonia from the fish waste will not be converted into the nitrates that the plants are seeking until this process is complete. Bacteria are venerated by aquaponic gardeners because they are the engine that drives the whole aquaponics systems. An aquaponics grow bed is serving a dual role of both home for the plants and bio-filter for the fish waste, both need to be considered and optimized.
From fish tank, ammonia-rich waste produced by fish mixed with water and travels through the pump then through the plants grow bed where it is filtered. Naturally occurring nitrifying bacteria convert ammonia from the fish waste into nitrites and then nitrates. Plants absorb the nitrates as nutrients.
After water is filtered by the plants, it returns to the fish tank. Fish breath in O2 and breath out CO2. Plants absorbs the carbon which leaves O2-rich waste for the fish tank. The goal of an aquaponic garden is to achieve a state of balance within its eco-system.
Everything that goes into the system must work towards this end goal, and not harm any other element of the system. In aquaponics, need only top up the fish tank with water and never dump and replace it unless there is a severe unexpected problem. It generates a complete eco-system in which various living creatures interact with each other to create a symbolic whole. The eco- system refers the place where plants, fish, bacteria, worms all live together in a beautifully balanced symbiotic relationship.
Inaquaponics method cucumber, tomato, bitter melon, bean, eggplant, mint, water spinach, pepper, lettuce, strawberry, grape and various herbal plants like Indian pennywort grows very well. With this plant species can also cultivate various native species of fish including horn, catfish, tilapia, koi, pabda, shrimp as well. Aquaponics can be as large as commercial food production or as small as desktop aquarium.
Positive thing is aquaponics is an environment friendly method because pesticides and antibiotics can disrupt the cycle, this system is completely natural. It saves resources for example, from the aspect of land resource, this system can be built in urban area or where fertile land is scarce, it uses one third of energy that other farm systems use and uses only 5% of the water volume required by regular vegetable crops.
By expanding the aquaponics system, it is possible to ensure the food security of Bangladesh in this global pandemic situation by meeting the demand for animal meat in the country and to produce vegetables and fruits that are free from any kind of toxins and harmful chemicals. For example, if lettuce and fish are farmed in the same aquaponics, it is possible to produce 7-8 tons of fish and 45,000 lettuce leaves per year.
Aquaponics is that kind of alternative system that can take crop production and fish farming a step further and at the same time assure food security and environmental protection of developing countries like Bangladesh in this crisis moment. Dipta Dey is a student, Institute of Forestry and Environmental Sciences, University of Chittagong.