Diversified cropping systems in a coastal province of the Mekong Delta, Vietnam: from testing to outscaling.

Abstract

This study was carried out to test the hypothesis that diversification and polyculture (growing more than one crop/commodity at the same time in the same field) could contribute greatly to increased profitability and reduced risk for both rice-based and shrimp-based production systems in the coastal zone. Local authorities, community associations and farmers collectively selected study sites in seven land-use zones (LUZ). In each study site, farmer communities selected one demonstration farm (demo) and five nearby farms (controls) where farming activities were managed under current practices. The demos tested new diversified cropping systems and new or improved technologies. At the end of each cropping season, farmer-managed on-farm workshops - in which the participants were local authorities, community associations, the press, farmers - were conducted to compare the ease of implementation, yields, profits and the benefit-cost of the demos and the controls. At the end of the 3-year study, final on-farm workshops were arranged to give final ratings and recommendations for the tested systems and technologies, which were endorsed by local authorities for wide dissemination, with support from extension workers, village authorities, community organizations and the mass media. The rice-rice&fish system was recommended for freshwater zones and the shrimp&crab-fish system for saltwater zones. For the intermediate water quality zone, the shrimp-rice&fish system was recommended only for areas near the freshwater zone. Component technologies recommended for outscaling included: new high-quality rice varieties; using a drum seeder for rice seeding; nitrogen fertilizer management using a leaf colour chart; appropriate stocking density of tilapia, anabas and silver carp for freshwater zones; and crab and elongated goby for saltwater zones. Extensive aquaculture techniques were recommended for shrimp in the shrimp-rice&fish system and semi-intensive for the shrimp&crab-fish system. After 3 years of study, approximately 8700 farmers adopted the recommended systems and technologies on 11,550 ha. The participatory approaches have been successful in outscaling diversified cropping systems and new technologies, generating more benefits to farmers.