Farmers’ Perceived Impact of High-Dikes on Rice and Wild Fish Yields, Water Quality, and Use of Fertilizers in the Mekong Delta, Vietnam

Abstract

This study assesses farmers' perceived impact of high-dikes on rice and fish yields, use of synthetic fertilizers, water quality, fish diversity, and inflow of nutrient-rich water and sediments in the Mekong Delta. Interviews were conducted with 89 farmers from three districts in the An Giang province, of which 69−98% of the agricultural land is covered by high-dikes. Only 57% of the farmers felt that the rice yields had increased after the construction of high-dikes. 93% of respondents perceived that the inflow of nutrient-rich water and sediments had decreased, and 99% felt that the use of synthetic fertilizers had increased by 26−37% after the construction of high-dikes. 94% of all farmers felt that high-dikes had impacted on the aquatic environment and water quality, which was perceived to have decreased from good to poor quality. The wild fish yield and fish diversity were estimated to have decreased by 68−83 and 75−81%, respectively, and had decreased most in Cho Moi, followed by Phu Tan and Chau Phu districts. It is concluded that high-dikes have helped to increase rice yields in some areas, but at the expense of decreased natural fertilization, water quality, fish diversity and yields, which all impact on the farmers' profit and well-being.