The Manila-based Asian Development Bank has approved a grant to support research on rice-fish farming, an ancient Asian method of farming fish in rice fields.

The grant has been extended to the International Center for Living Aquatic Resources Management, which will conduct research on the farming system for farmers.

Cultivating fish in rice fields has been practiced for more than 1,500 years in Asia, the IADB said, but has been declining in recent years. The assistance grant will be used to develop improved methods of raising fish in rice paddies, in an attempt to increase the productivity of Asian farmers.

The Asian Rice Farming Systems Network, in cooperation with ICLARM, will set up research-based farming systems in Bangladesh, India, Indonesia, Philippines and Thailand.

Rice-fish farming has shown greatly increased yields in rice, said Mayo Martin of the Fish Farming Experimental Station in Stuttgart, Ark., a Department of the Interior project experimenting with similar farming methods.

"They feed the fish, which in turn fertilize the rice," he said. The U.S. project also has experimented with rotating fields with rice and fish, a method that has proved effective.

In Asia, farmers grow short- to medium-grain rice, which tolerates flooding of up to 20 inches, Mayo said. U.S. farmers, on the other hand, grow long-grain rice, which tolerates six to eight inches of water and makes fish production impossible, he said.

The IADB grant also will support collaborative research on rice-fish farming between the ICLARM, the Central Luzon State University and the International Research and Rice Institute. Meetings and workshops will be held to discuss research findings, the IADB said.