Published online by Cambridge University Press: 27 March 2009
Field experiments were conducted for three consecutive years during 1988–90 at a research farm near the Indian Institute of Technology, Kharagpur, West Bengal, India to study the influence of organic and inorganic fertilizers on the performance of rice and fish in a dual culture system. Under waterlogged conditions the grain yield and dry matter of the rice variety CR1018 was increased both when inorganic N fertilizer (50 kg N/ha) was supplied or when a combination of organic (lOt FYM/ha) and inorganic N fertilizer (25 kg N/ha) were applied as compared with an organic fertilizer alone (20 t FYM/ha). The recovery of N as well as grain yield response per kg of N applied was also greater when inorganic N was applied. On the other hand, the growth of the fish species Java punti (Puntius javanicus) when grown alone (monoculture) and Catla (Catla catla), Mrigal (Cirrhinus mrigala) and Java punti (Puntius javanicus) grown together (polyculture) in the rice field was found to be superior when organic fertilizer was applied either alone or in combination with an inorganic fertilizer. The total number of phytoplankton species as food for the fish under organic manuring was more than under inorganic fertilization. In low-lying waterlogged situations (15–45 cm water depth), the total productivity could be increased by supplying the appropriate nutrition to both rice and fish in such dual culture systems.