Figure 1. Simplified nutrient flows
To understand the rice-fish ecosystem as discussed in this paper, here are some terms to note:
- organic - available also to fish, plankton, algae, soil, fauna and bacteria
- inorganic - available only to rice crops, macrophytes/algae/weeds, phytoplanktons and bacteria.
- produces food from simple nutrients using sun's energy;
- plants, algae and phytoplankton are food for fish, insects, zooplankton and soil fauna
Figure 2. Ecosystem components
Conceptual food chain for fish in the system
Issues for further consideration
The ricefield environment is a specialized culture environment for fish that can be exploited best through certain types of polyculture.
Fish such as common carp, through their foraging behaviour, aerate the topmost sediment layer and enhance the aerobic bacterial decomposition process thereby ensuring the release of inorganic nutrients at a rapid rate.