Shedding Light on Agricultural Transitions, Dragon Fruit Cultivation, and Electrification in Southern Vietnam Using Mixed Methods

Agricultural transition represents an essential component of land use and land cover change in countries across the world, as economic and social factors pressure agriculturalists out of traditional subsistence farming into commodity production. Modernization has altered modes of income, land ownership, and livelihood in Southeast Asia drastically in recent years. The Binh Thuan Province of southern Vietnam experienced a particularly radical transformation with the introduction of dragon fruit (Hylocereus undatus) cultivation, which has been profoundly encouraged by outside markets in China, Australia, Japan, and the United States. Dragon fruit plantation dynamics and recent expansion are captured via remotely sensed nighttime lights (NTL) data acquired by the Suomi National Polar-orbiting Partnership Visible/Infrared Imager/ Radiometer Suite (VIIRS), revealing a seasonal signal important for differentiating various land uses on the ground. We employed the Breaks for Additive and Seasonal Trend (BFAST) algorithm to reduce and summarize seasonal trends in NTL data and then used the BFAST output combined with a Normalized Difference Lights Index (NDLI) value for each year in the period of 2012 through 2018 in a decision tree classifier to differentiate dragon fruit land use from city lights across the province. The final output was contextualized with a series of semistructured interviews to examine and characterize a changing agricultural landscape associated with dragon fruit cultivation. Dragon fruit plantation in southern Vietnam follows the land system transition pathways of many other agricultural contexts but presents unique physical and social outcomes for further investigation.