Introduction
Rice-fish farming as a farm diversification strategy was introduced to smallholder rice farmers as an approach to transform their traditional ricefield environments into a more productive, resilient, and biologically diverse agro-ecological landscape, with efficient use of land and water resources to produce fish in addition to rice within their existing ricefields. The intervention focused on generating entry-level advice for rice farmers with little or no knowledge of aquaculture.
The integration process
The process kick-started through series of community engagements with rice farmers, farmer groups and community leaders, to assess existing rice farming practices, identify wetland areas suitable for rice-fish farming and to understand farmer needs for ricefield adaptation to include fish. The diversification process involved ricefield modification- digging fish trench of 1.5m width and 0.7m depth round the edges of an 18m X 30m rice production area. Rice variety (FARO-40-National code: NGOS-91-40)) was planted at 20 X 20 cm spacing, and 1, 800 juveniles of Catfish (Clarias gariepinus) of 8-10 g average size were stocked and fed two times a day with fish feed developed by the project. After 3 months of co-culture of rice, 250 – 300g fish were harvested, and processed for smoked fish market. The process was carried out in 6 different pilot plots in the Northern and Southern regions of Nigeria.
Lessons learned and recommendations
Water retention in rice field trenches: Leaching of water and rapid evaporation were observed during the dry season. In the absence of a working irrigation structure, additional cost of pumping water for replenishment may not be sustainable for farmers with limited financial resources. The initial adaptation measure employed was to lay plastic bags inside the trenches to hold water for longer period. However, for environmental sustainability consideration, the plastic lining was discouraged, and thus rice-fish farming is encouraged during the wet/rainy season.
Fish seed availability: Limited access to fish seed was reported by the farmers. The solution underway is to train farmers on low-cost fish breeding techniques, thus improving availability within their locality.
Predation from birds: Loss of fish due to predation from birds was recorded. The use of net covering and stocking of fish of bigger size were recommended to prevent actions of the predatory birds.
Fish size at harvest: The fish were harvested at 250-350 g after 3 months of co-culture with rice. Although the size was not competitive for the desired size in Nigeria fresh fish market, value-addition through smoking was introduced to boost the economic value of the fish, noting that smoked fish commands high market value irrespective size.
Expensive commercial feed: The cost of commercial fish feed was challenging to the farmers. The project therefore introduced alternative feeds, using locally sourced feed ingredients (rice bran, fish offal) for feed formulation. Also, there is an ongoing process to develop a training protocol for farmers on using black soldier fly larva as alternative fish feed.
Knowledge sharing among project beneficiaries: Farm diversification processes slightly differ from plot to plot. Therefore, farmer-farmer knowledge exchange and experience sharing are considered an important aspect of knowledge transfer and information dissemination among practitioners.
Conclusion
The trials demonstrated how promoting small-scale, inexpensive integrated agriculture-aquaculture farming not only provides an immediate boost to the local supply of nutritious food (fish) in addition to rice for home consumption but can also generate significant income through sales. These are the reports from the farmers that has adopted the technology.
Keywords: Diversification, rice, fish, rice-fishÂ