Tubificid worms that live in the paddy mud increase in numbers when an organic fertilizer is applied. They mix the soil by passing it through their gut as well as by their burrowing and respiratory movements, thereby checking the sprouting of paddy weeds. Tubificids inhabiting the pond's mud also serve as fish food. It is suggested that such a pond might be appropriate for aquaculture.
This study considers a method to control paddy field ecosystems based on the above to produce rice and freshwater fish, with organic fertilizers but without the use of herbicides and insecticides.
