Environmental and socio-economic impacts of integrated rice-shrimp farming : companion modelling case study in Bac Lieu province, Mekong Delta, Vietnam

Abstract

Currently, there are three critical issues of conflict over water demand, the potential for extreme poverty coupled with economic differentiation, and the potential effect of soil salinization on rice production in rice-shrimp farming systems. The thesis aims to better understand conflicts on land use and water quality between rice and shrimp culture, individual’s responses coping with bio-physical and social conditions, and economic differentiation in Bac Lieu province, Mekong Delta, Vietnam by using Companion Modelling (ComMod) approach including role playing game (RPG) and agent-based model (ABM). In the study, two successive RPG sessions and a RiceShrimpMD ABM were co-constructed between researchers and local involved stakeholders over the period 2006-2009. Lessons learned from the RPGs and five-year simulation results of the RiceShrimpMD ABM show that conflict over water demand for rice and shrimp crop occurs when both rice and shrimp crops coexist in the same period within a plot after September, which is the proposed time to start rice crops. In downstream locations of the province, more conflicts occurred in the scenario where earlier salinity over 5ppt was provided in December and without any application for serving appropriate environmental conditions on rice crop. In case of extreme poverty, it also indicates that accumulated household capital and economic differentiation occurred whenever people had less concern to practice rice in rice-shrimp farming system , especially in the downstream location; rice yield reduced a bit due to the effects of salinization, compared to normal yield in the drought-free year. However, this environmental impact can be avoided as rice crops are annually practiced. Income obtained from rice crop is an essential compensation to reduce extreme poverty in a household. Therefore, sustainable agricultural development in Bac Lieu province is likely a dynamic process that is challenged by a wide range of biophysical and socio-economic factors at both the macro level of policy makers and water management schemes to the micro level of household decision making. Extreme poverty coupled with economic differentiation is also challenging for future sustainability. This study is confident that the companion modeling approach is an appropriate methodology for opening opportunity to all relevant stakeholders to share their knowledge of and a dialogue on water demand, enhancing better understanding of and collaboration on water management issues for sustainable development