Economic impact of rice-fish farming in paddy (A case study: Fouman, Astaneh-Ashrafieh and Rasht in Guilan province)

Shortage of natural resources and fear of food supply for growing population in the world caused optimal consumption of resources become great concern. To evaluate economic impact of rice-fish farming under paddy field condition, a split plot experiment based on randomized complete block design with three replications was carried out in three locations (Astaneh-Ashrafieh, Fouman and Rasht), Guilan province, Iran. Two field conditions (with and without fish) were considered as main factor and six rice varieties (three local varieties, Hashemi, Hasansaraie and Hassani and three improved cultivars, Khazar, Dorfak and Bahar1-hybrid rice) as sub-factor. Some small fishes weighting about 30-70 g (from the kinds of grass fish, Amour; common fish, Kapour and silver fish, Phytophak and Big head) were released in the pool at the same time with transplanting. About 25-30 days after transplanting, by removing the temporary border made in surrounding of fields and raising the water level of the field, it was possible to move the fishes to the rice fields. Results of the combined analysis of variance showed significant differences among varieties for all studied traits and between two culture types for all studied traits except for grain yield and number of unfilled grains. The interaction effects of culture type × location, culture type × variety and variety × location were also significant for grain yield. Evaluation of the grain yield of rice varieties in rice-fish farming indicated that rice and fish are complementary products for improved cultivars (except Bahar1 in Fouman) and competing products for local varieties (except Hassani in Rasht). With respect to the fish performance, the average profits of improved cultivars was 2.3 times/ ha more than local varieties.