Search

Vietnam is a major rice producer, and much of the rice grown is concentrated in the Red River Delta (RRD) and the Mekong River Delta (MRD). While the two deltas are highly productive regions, they are vulnerable to natural hazards and the effects of human-induced environmental change. To show that the processes and issues affecting food security are reinforcing, interdependent and operating at multiple scales, we used a systems-thinking approach to represent the major linkages between anthropogenic land-use and natural hazards and elaborate on how the drivers and environmental processes interact and influence rice growing area, rice yield and rice quality in the two deltas. On a local scale, demand for aquaculture and alternative crops, urban expansion, dike development, sand mining and groundwater extraction decrease rice production in the two deltas. Regionally, upstream dam construction impacts rice production in the two deltas despite being distally situated. Separately, the localized natural hazards that have adversely affected rice production include droughts, floods and typhoons. Outbreaks of pests and diseases are also common. Climate-change-induced sea level rise is a global phenomenon that will affect agricultural productivity. Notably, anthropogenic developments meant to improve agricultural productivity or increase economic growth can create many unwanted environmental consequences such as an increase in flooding, saltwater intrusion and land subsidence, which in turn decreases rice production and quality. In addition, natural hazards may amplify the problems created by human activities. Our meta-analysis highlights the ways in which a systems-thinking approach can yield more nuanced perspectives to tackle “wicked” and interrelated environmental challenges. Given that deltas worldwide are globally significant for food production and are highly stressed and degraded, a systems-thinking approach can be applied to provide a holistic and contextualized overview of the threats faced in each location.

Vietnam is a major rice producer and much of the rice grown is concentrated in the Red River Delta (RRD) and the Mekong River Delta (MRD). While the two mega-deltas are highly productive regions, they are vulnerable to natural hazards and the effects of human related environmental change. The natural hazards that affect Vietnam include typhoons, floods and droughts while the major anthropogenic developments happening in Vietnam include dike development, sand mining, dam construction and groundwater extraction. Outbreaks of pests and diseases are also common. Although there is a substantial volume of work investigating the environmental impacts of these natural hazards and anthropogenic interventions, few studies have examined the implications of these on food security. To show that the processes and issues affecting food security are reinforcing and interdependent, we used a systems thinking approach to represent the ways in which natural hazards, anthropogenic land-use and climate change affect rice production in the two mega-deltas. A key finding is that anthropogenic developments meant to improve agricultural productivity or increase economic development create many unwanted environmental consequences such as an increase in flooding, saltwater intrusion and land subsidence which in turn create other negative feedbacks on rice production and quality. In addition, natural hazards may amplify the problems created by human activities. In future, besides creating new environmental threats, climate change may exacerbate the effects of natural hazards by increasing the frequency and severity of natural disasters. Our meta-analysis highlights the ways in which a systems thinking approach can yield more nuanced perspectives to tackle complex and interrelated environmental challenges. Given that mega-deltas worldwide are globally significant for food production and are highly stressed and degraded landscapes, a systems thinking approach can be applied to provide a holistic and contextualized overview of the threats faced in each location.

Vietnam is one of the world’s top two rice exporting countries. However, rice cultivation is the primary source of agriculture’s greenhouse gas (GHG) emissions in Vietnam. In particular, strategies are required to reduce GHG emissions associated with the application of organic and inorganic fertilisers. The objective of this study was to assess the effects of various combinations of biochar (BIOC), compost (COMP) and slow-release urea (SRU) on methane (CH4) and nitrous oxide (N2O) emissions. In total, 1170 gas samples were collected from closed gas chambers in rice paddies at Thinh Long commune and Rang Dong farm in northern Vietnam between June and October 2014. The gas samples were analysed for CH4-C and N2O-N fluxes using gas chromatography. The application of BIOC alone resulted in the lowest CH4 emissions (4.8–59 mg C m−2 h−1) and lowest N2O emissions (0.15–0.26 µg N m−2 h−1). The combined application of nitrogen–phosphorus–potassium (NPK) + COMP emitted the highest CH4 (14–72 mg C m−2 h−1), while ½NPK + BIOC emitted the highest N2O (1.03 µg N m−2 h−1 in the TL commune), but it was the second lowest (0.495 µg N m−2 h−1) in the RD farm. Green urea and orange urea reduced N2O emissions significantly (p