Two enterprising youth in Kenya are championing green farming revolution by integrating hydroponic and aquaculture to form aquaponic system that entirely eliminate chemical usage and generating over Sh3million annually.
The duo Samuel Gitimu and Edward Nyagah who are passionate about new age farming sought the new model in order to help empower farmers as well as ensuring that systems safeguard the environment as opposed to the conventional new age farming which advocates for massive use of chemicals. “Our system integrates the plants and fish and therefore the two become symbiotic in nature ultimately forming a long term sustainable green model,” noted Gitimu.
According to Gitimu, they borrowed the model from Australia and localized it. The power and demand of the system dawned on the two when it was voted the best model in a contest dubbed Nature Challenge in 2012 organized by WWF,NETFUND to foster green farming techniques that are safeguarding the environment and promising higher food returns.
After this successful contest, Gitimu and Nyagah decided to scale up the model into a much bigger project that would generate revenues. “Initially we had a small miniature system that was meant for our experiment but after seeing the demand and the success the model was promising, in 2008, we scaled it and started commercial production as well as using it for demonstration purposes. The duo planted pepper mint, straw berries and introduced tilapia in the fish pond.
The system works best in a greenhouse structure. For instance, 8 by 15 metres greenhouse size according to Gitimu is able to accommodate about 1000 strawberry plants and over 1000 tilapia earning one over Sh3million annually based on three harvests per year. “One can harvest 15 tonnes of straw berries per year and 6 tonnes of tilapia from the system hence the guaranteed returns,” noted Gitimu.
Setting up the system depends on the location and climate conditions. Fish pond or fish tank is set up in one end of the green house and the plants are grown on grow bed which is either gravel, rocks, coconut shells etc. “The aim is to use soilless medium to grow the crops because unlike the general perception that crops need soil to grow, its only the water and nutrients that the crops need in order to flourish. Our system guarantees that and therefore the crops inside the structure all depend on these nutrients from the water which is generated by the fish,” explained Gitimu.
The growing medium is inserted into vertically placed plastic towers with an optimum height of about 2 metres. Each pipe is partitioned into an opening mini grow bed where a plant is introduced with one pipe able to accommodate over 10 plants. The pipes have plumbing system with water pipes running from the fish tank/pond to the vertical plastic pipes which support the plants.
The fish tank has a timer and water pump. Depending on the set time, the pump can either pump the water after every 30 minutes with the water running for about 3 minutes to the plants and back to the pond.
The plant and fish depend on each for survival in this system. The fish is fed on the available fish feeds that are introduced to the pond by the farmer. The fish excretes ammonia which pollutes the water in the pond. When the timer is released and water is automatically pumped to the plants through the piping system in the vertical plastic towers, the plant utilize the ammonia produced by the fish and eventually release only ‘ammonia free’ water back to the pond which in itself is fresh purified water vital for the fish survival and faster growth.
“Our fish under this system matures 4-5 weeks faster due to increased fresh water circulation which is always rare in other conventional fish ponds,” added Gitimu. The plants on the other hand are guaranteed chemical free nutrients. The waste from the fish ammonia introduces two bacterias into the towers; nitrosomonas which converts ammonia into Nitrite and Nitrobacter which converts Nitrite into nitrate.
These two components become the fertilizer; vital nutrients for the plants and during the conversion process, the water is filtered and purified hence running back to the pond while fresh for the fish. In addition, Gitimu noted that the model helps save water because there is minimal water loss as there is no outlet on the fish pond/tank. “In every harvest, we estimate about 1.5 percent water loss which is negligible and very economical as opposed to other conventional farming methods where water lost 100 percent.”
The model takes about a week to be set up by the duo although the pricing depends on the size material specifications. The demand for the system has seen the duo pool clients from as far as Rwanda, Tanzania and Uganda. Last year alone, over 12 systems were set up by the duo and the demand is growing steadily.
Due to the innovativeness and the guarantee of food security that the model promises, the duo have been selected to be among the finalists of the 2014 GrowthAfrica Agribusiness Accelerator training that is aimed at empowering them with better skills to improve on the system and even offer them a platform to pitch their idea to investors for more funding.