Dynamics of sustainability in integrated agriculture : aquaculture systems in the Mekong Delta

Key words: Mekong Delta; IAA; ECOPATH; Nutmon; LCA; environmental impact; sustainability In the Mekong Delta (MD), intensification and modernization of crop, fish and livestock production causes concern about sustainable use of natural resources. The objectives of this research were to understand the driving forces for changes in farming practices, and to quantify and evaluate agro-ecological attributes, nutrient balances, and environmental impacts in Integrated Agriculture-Aquaculture (IAA) systems. Three districts differing in cropping patterns and intensity of fish culture were selected for this study: a rice-based and high input fish system (R-HF) in O Mon district, a rice-based and medium input fish system (R-MF) in Tam Binh district, and an orchard-based and low input fish system (O-LF) in Cai Be district. Two surveys (2002 and 2004), covering 90 households, were carried out to analyse drivers for changes in IAA systems. Another survey was conducted at the end of the study to evaluate the awareness of farmers on sustainability issues. One extra survey (2005) was conducted to analyse the impact of the Avian Influenza (AI) outbreak on livelihoods. Eleven farms were selected for detailed monitoring of inputs, outputs and internal bio-resource flows of rice, fruits, vegetables, pigs, poultry, and fish over a period of two years (2002-2004). The agro-ecological attributes of the selected farms were quantified using ECOPATH. The adapted Nutmon (Nutmon-Asia) model was used to quantify soil nutrient balances. A detailed cradle-to-farm-gate life cycle assessment (LCA) was performed to assess the integral environmental impact of IAA farming. The policy of economic liberalization, introduction of modern rice varieties, increasing market demands, and natural disasters were main drivers for changes in IAA farming systems. Well-off farmers tended to intensify their farming practices, whereas the poorer farmers tended towards diversification to safeguard their livelihoods and avoid risks. The ECOPATH, Nutmon-Asia and LCA modelling approaches proved complementary in analysing agro-ecological performances, identifying ecological sustainability issues, and quantifying sustainability indicators at farm and farming system level. The 19 agro-ecological attributes, quantified by ECOPATH, were combined into four sustainability factors: Productivity-Efficiency, Diversity, Maturity, and Aquaculture Integration. Rice-based farms (R-HF and R-MF) were more efficient and productive than the orchard-based farms (O-LF) and recycled nitrogen more intensively within the farm. Productivity-Efficiency was directly related to sustainability of farms. A high farm output in relation to external input use could be achieved both by farms with low external input use and by farms with a relatively high external input use. Soil nutrient balances are important indicators of nutrient use efficiency of farming systems. The Nutmon-Asia results showed that all farms in the three systems had positive nutrient balances of nitrogen, phosphorus and potassium. A negative potassium balance was found in the rice fields of all three systems. Improvements of the nutrient balances can start by lowering the quantity of fertilizers applied. LCA was used to quantify the use of resources and environmental emissions per kcal and kg farm product, and per farm. Land use and energy use per kcal farm product did not differ among the three systems. However, global warming potential (GWP), eutrophication potential (EP), and acidification potential (AP) per kcal farm product were higher in O-LF than in R-HF and R-MF, mainly due to the low calorie content of the two main products, fruits and vegetables, and the small fish yield in O-LF. One kg of fish produced in O-LF farms showed a higher land use, energy use, GWP, EP, and AP than the average kg of fish produced in the other two systems. Overall, rice and pigs were the main contributors to the environmental impact of food production in the MD. Excessive and inefficient use of fertilizers, and CH4 emission from the paddy fields contributed most to the environmental impact in rice production, whereas the use of external feeds contributed most to the impact in pigs. The IAA farmers profited from their flexibility and diversity in farming activities during the period of the AI outbreaks. Farmers were more concerned about social than economic and ecological sustainability issues. The O-LF system scored less on some of the ecological sustainability issues and the O-LF farmers were also less aware of the importance of these issues. Intensification of farming practices will continue. For enhancing nutrient recycling on the farms, emphasis should be on maintaining traditional sustainable farm practices, such as re-use of crop and animal wastes within the farm and integrating fish ponds and using of pond sediment as crop fertilizer. Research, development and extension services should pay attention to strategies for increasing resilience of IAA systems in the MD, by focusing on reducing external farm inputs and improving farm nutrient management. In the MD the demands for animal protein will increase. Stimulation of aquaculture seems more appropriate than stimulation of pig and poultry production, seeing that the environmental impacts per kg protein for fish were lower than for pigs and poultry. <br/

Environmental impact assessment of the pangasius sector in the Mekong Delta

In the past seven years the export of white pangasius fillets grew fast. The culture method shifted to intensive production of striped catfish (Ca Tra) in deep ponds because this is more efficient than the pen and cage culture of Ca Basa. Today, striped catfish comprises more than 90 % of the culture. The increased production was achieved by producers investing in large ponds. The market chain is gearing towards vertical integration. Most farms keep fish at relatively high densities of 15 to 25 fish/m3 in ponds having a depth of up to 4m, and are advised to exchange daily 20 to 40% of the water. The sustainability of the sector is threatened due to the increased environmental pressure, and hampered by the growing cost of inputs and reduced farm-gate prices of the fish. The Environmental Impact Assessment (EIA) intends to identify measures for preventing or mitigating the environmental impacts of catfish culture in the Mekong Delta. The EIA was a seven-step process during which we interacted twice with part of the main stakeholders. To build trust among the stakeholders from the sector, we conducted the scoping and goal setting with them

Dynamics of sustainability in integrated agriculture : aquaculture systems in the Mekong Delta

Key words: Mekong Delta; IAA; ECOPATH; Nutmon; LCA; environmental impact; sustainability In the Mekong Delta (MD), intensification and modernization of crop, fish and livestock production causes concern about sustainable use of natural resources. The objectives of this research were to understand the driving forces for changes in farming practices, and to quantify and evaluate agro-ecological attributes, nutrient balances, and environmental impacts in Integrated Agriculture-Aquaculture (IAA) systems. Three districts differing in cropping patterns and intensity of fish culture were selected for this study: a rice-based and high input fish system (R-HF) in O Mon district, a rice-based and medium input fish system (R-MF) in Tam Binh district, and an orchard-based and low input fish system (O-LF) in Cai Be district. Two surveys (2002 and 2004), covering 90 households, were carried out to analyse drivers for changes in IAA systems. Another survey was conducted at the end of the study to evaluate the awareness of farmers on sustainability issues. One extra survey (2005) was conducted to analyse the impact of the Avian Influenza (AI) outbreak on livelihoods. Eleven farms were selected for detailed monitoring of inputs, outputs and internal bio-resource flows of rice, fruits, vegetables, pigs, poultry, and fish over a period of two years (2002-2004). The agro-ecological attributes of the selected farms were quantified using ECOPATH. The adapted Nutmon (Nutmon-Asia) model was used to quantify soil nutrient balances. A detailed cradle-to-farm-gate life cycle assessment (LCA) was performed to assess the integral environmental impact of IAA farming. The policy of economic liberalization, introduction of modern rice varieties, increasing market demands, and natural disasters were main drivers for changes in IAA farming systems. Well-off farmers tended to intensify their farming practices, whereas the poorer farmers tended towards diversification to safeguard their livelihoods and avoid risks. The ECOPATH, Nutmon-Asia and LCA modelling approaches proved complementary in analysing agro-ecological performances, identifying ecological sustainability issues, and quantifying sustainability indicators at farm and farming system level. The 19 agro-ecological attributes, quantified by ECOPATH, were combined into four sustainability factors: Productivity-Efficiency, Diversity, Maturity, and Aquaculture Integration. Rice-based farms (R-HF and R-MF) were more efficient and productive than the orchard-based farms (O-LF) and recycled nitrogen more intensively within the farm. Productivity-Efficiency was directly related to sustainability of farms. A high farm output in relation to external input use could be achieved both by farms with low external input use and by farms with a relatively high external input use. Soil nutrient balances are important indicators of nutrient use efficiency of farming systems. The Nutmon-Asia results showed that all farms in the three systems had positive nutrient balances of nitrogen, phosphorus and potassium. A negative potassium balance was found in the rice fields of all three systems. Improvements of the nutrient balances can start by lowering the quantity of fertilizers applied. LCA was used to quantify the use of resources and environmental emissions per kcal and kg farm product, and per farm. Land use and energy use per kcal farm product did not differ among the three systems. However, global warming potential (GWP), eutrophication potential (EP), and acidification potential (AP) per kcal farm product were higher in O-LF than in R-HF and R-MF, mainly due to the low calorie content of the two main products, fruits and vegetables, and the small fish yield in O-LF. One kg of fish produced in O-LF farms showed a higher land use, energy use, GWP, EP, and AP than the average kg of fish produced in the other two systems. Overall, rice and pigs were the main contributors to the environmental impact of food production in the MD. Excessive and inefficient use of fertilizers, and CH4 emission from the paddy fields contributed most to the environmental impact in rice production, whereas the use of external feeds contributed most to the impact in pigs. The IAA farmers profited from their flexibility and diversity in farming activities during the period of the AI outbreaks. Farmers were more concerned about social than economic and ecological sustainability issues. The O-LF system scored less on some of the ecological sustainability issues and the O-LF farmers were also less aware of the importance of these issues. Intensification of farming practices will continue. For enhancing nutrient recycling on the farms, emphasis should be on maintaining traditional sustainable farm practices, such as re-use of crop and animal wastes within the farm and integrating fish ponds and using of pond sediment as crop fertilizer. Research, development and extension services should pay attention to strategies for increasing resilience of IAA systems in the MD, by focusing on reducing external farm inputs and improving farm nutrient management. In the MD the demands for animal protein will increase. Stimulation of aquaculture seems more appropriate than stimulation of pig and poultry production, seeing that the environmental impacts per kg protein for fish were lower than for pigs and poultry

Life cycle assessment of food production in integrated agriculture–aquaculture systems of the Mekong Delta

This study evaluated the environmental impact of integrated agriculture–aquaculture (IAA) farming systems in the Mekong Delta that differ in types of aquaculture intensification. Daily inputs and outputs for rice, fruits, vegetables, pigs, poultry, and fish were collected on 11 farms over a period of two years: three farms in a rice-based and high input fish system (R-HF); four in a rice-based and medium input fish system (R-MF); and four in an orchard-based and low input fish system (O-LF). For each farm, a detailed cradle-to-farm-gate life cycle assessment was performed. Kcal as functional unit (FU) enabled a comparison of the integral environmental impact among farming systems, and identification of major processes influencing the outcome of an impact category. kg product as FU enabled evaluation of impacts for the individual products of IAA farms. The environmental impact was also quantified for each farm as a whole to identify which farm components explained the majority of the environmental impact in absolute terms. Land use per kcal farm product did not differ among the three farming systems. Global warming potential (GWP), energy use and eutrophication potential (EP) per kcal farm product tended to be higher, whereas acidification potential (AP) was higher, in O-LF than in R-HF and R-MF, mainly due to the low calorie content of the two main products, fruits and vegetables, and the small fish yield in O-LF. One kg of fish produced in O-LF farms showed 28% higher land use, 35% higher energy use, 54% higher GWP, 45% higher EP, and 52% higher AP than the average kg of fish produced in the other two systems, due to the pond management system and small fish yield in O-LF. For each impact category, the impact per kg pig and poultry protein were on average 1.6–1.8 times higher than the impacts per kg fish protein. Overall, rice and pigs were the main contributors to the environmental impact of food production in the MD. Excessive and inefficient use of fertilizers, and CH4 emission from the paddy fields contributed most to the environmental impact in rice production, whereas the use of external feeds contributed most to the impact in pigs

Life cycle assessment of food production in integrated agriculture–aquaculture systems of the Mekong Delta

This study evaluated the environmental impact of integrated agriculture–aquaculture (IAA) farming systems in the Mekong Delta that differ in types of aquaculture intensification. Daily inputs and outputs for rice, fruits, vegetables, pigs, poultry, and fish were collected on 11 farms over a period of two years: three farms in a rice-based and high input fish system (R-HF); four in a rice-based and medium input fish system (R-MF); and four in an orchard-based and low input fish system (O-LF). For each farm, a detailed cradle-to-farm-gate life cycle assessment was performed. Kcal as functional unit (FU) enabled a comparison of the integral environmental impact among farming systems, and identification of major processes influencing the outcome of an impact category. kg product as FU enabled evaluation of impacts for the individual products of IAA farms. The environmental impact was also quantified for each farm as a whole to identify which farm components explained the majority of the environmental impact in absolute terms. Land use per kcal farm product did not differ among the three farming systems. Global warming potential (GWP), energy use and eutrophication potential (EP) per kcal farm product tended to be higher, whereas acidification potential (AP) was higher, in O-LF than in R-HF and R-MF, mainly due to the low calorie content of the two main products, fruits and vegetables, and the small fish yield in O-LF. One kg of fish produced in O-LF farms showed 28% higher land use, 35% higher energy use, 54% higher GWP, 45% higher EP, and 52% higher AP than the average kg of fish produced in the other two systems, due to the pond management system and small fish yield in O-LF. For each impact category, the impact per kg pig and poultry protein were on average 1.6–1.8 times higher than the impacts per kg fish protein. Overall, rice and pigs were the main contributors to the environmental impact of food production in the MD. Excessive and inefficient use of fertilizers, and CH4 emission from the paddy fields contributed most to the environmental impact in rice production, whereas the use of external feeds contributed most to the impact in pigs

Environmental comparison of intensive and integrated agriculture-aquaculture systems for striped catfish production in the Mekong Delta, Vietnam, based on two existing case studies using life cycle assessment

Vietnam is the largest producer for the export of striped catfish. Traditionally striped catfish production in the Mekong Delta took place in integrated agriculture–aquaculture systems, but has shifted recently to intensive systems to meet increasing export demands. A recent study quantified the environmental impact of intensive striped catfish production in Vietnam. Another did the same for integrated systems. Both studies used life cycle assessment, covered similar environmental impact categories, and were roughly matched in the production stages included. However, an environmental comparison of both systems has not been made so far. The objective of this paper is to make a comparative life cycle assessment of striped catfish production in intensive and integrated systems. The comparison was based on existing life cycle assessments on these systems, but their methodological choices and data had to be aligned. The results show that striped catfish production in intensive systems contributes considerably more to seven of the nine assessed impact categories (global warming, ozone depletion, acidification, eutrophication, photochemical oxidation, human toxicity, freshwater ecotoxicity, marine aquatic ecotoxicity, fossil depletion). Only contributions to eutrophication and freshwater ecotoxicity were higher for the integrated systems than for the intensive systems. In both systems, grow-out fish farming contributes most to eutrophication and freshwater ecotoxicity, whereas feed production contributes most to all other impact categories. The environmental performance of integrated striped catfish production is convincingly better in most impact categories. This raises questions about whether (elements of) these systems can be used to mitigate the environmental impact of intensive striped catfish production