Rice-shrimp farming in the Mekong Delta: biophysical and socioeconomic issues

Abstract

Abstract The study area is situated in the southern part of National Highway No. 1 in Gia Rai District(Bac Lieu Province) where farmers have traditionally practised rain-fed rice cultivation.However, in the last five years the high profits possible from shrimp production have led manyfarmers in the study area to convert their rice fields to shrimp production. This has occurred withlimited land use planning from government. In this study the suitability of land under differentfarming practices (in particular rice–shrimp farming) is assessed and recommendations are madefor land use planning. These recommendations incorporated government objectives and theneeds of local farmers. The study involved both soil and household surveys where a total of 249soil observation points were made and a total of 264 households were interviewed aboutsocioeconomic concerns. Land mapping units (LMU) were employed as a basis for the landevaluation. The land mapping units were identified on the basis of combinations of climatic, soiland hydrological characteristics — each of the 22 LMUs identified can be described in terms ofsoil type, rainfall, length of rainy period, maximum inundation depth, length of inundationperiod, tidal magnitude and present land use. The biophysical qualities of each LMU werecombined with information about the required land qualities of four key land use types (LUT)to provide insights for land use planning in the study region. The land use types included in thestudy were double rice cropping (LUT1), rice–shrimp (LUT2), improved–extensive shrimp(LUT3), and extensive shrimp (LUT4). The results showed that only LUT3 and LUT4 werehighly and moderately suitable for all LMUs, indicating that there is potential for fisherydevelopment in the study area. In several of the LMUs, however, LUT1 was found to be highlysuitable and LUT3 and LUT4 only moderately to marginally suitable. The results from theassessment of land suitability were used to evaluate three land-use planning scenarios. Thesescenarios were: 1. maximise rice area; 2. maximise shrimp area; 3. develop separate zones forintensive rice cultivation and shrimp-based systems prioritising rice–shrimp systems. The localgovernment objectives are most supportive of scenario 3; therefore, in this paper only the resultsfor this scenario are shown