Seawater Farms Vietnam (SFV)
Vietnam is an agriculture powerhouse dominated by small-scale independently owned farms growing a wide range of crops, both on land and in water. Climate projections for the next century predict drastic changes to Vietnam’s landscape and economy. With seawater levels rising by a national average of 3cm per year and more than 31 million people expected to live below the high tide line by 2050, Moody’s recently rated the Vietnamese economy among the world’s most exposed to climate change.
The intrusion of saline water deeper inland already effects more than 2.1 million hectares of farmland each year. This year saline water reached more than 70km upriver, causing freshwater shortages for up to 600,000 people. The issue has now become so prevalent that salinity intrusion is now reported in the daily national news – just before the weather. With so many farmers now unable to produce crops, the national government and other multinational organizations are rushing to devise solutions to this emerging problem.
There are more than 700,000ha of land in Vietnam dedicated to shrimp farming – all of which is flooded with saline water by necessity. Our system makes use of the abundant nutrients available in effluent ponds and sludge disposal sites to grow these high-value crops in land that is otherwise unprofitable. Our crops also benefit shrimp farming by cleaning water and removing nitrogenous and phosphorous wastes. Research has found that samphire floating beds remove 1-3g nitrogen per m2 production per day. We hope to use this capability to lower the environmental footprint at shrimp farms while also giving farmers an alternative income stream.
Every year rice farmland along the coastline and more than 70km inland of the Mekong Delta (Vietnam’s most productive agriculture region) is affected by salinity intrusion during the dry season. . Between January and April 2020, more than 50,000 hectares of rice farm land across the delta have already been damaged. Causing the vast majority of famers in the delta to harvest early. The national government has already invested more than 22 million USD to mitigate the issue.
Our crops are not only salinity tolerant but grow naturally in flooded salt marshes and do not require significant changes to a rice paddy system. By introducing halophyte crops to rice farms affected by salinity inundation, farmers will be able to generate valuable alternative income during the dry season, and on degraded or unusable land.
We are developing three types of systems
Water treatment reservoir – Saline crops grown on floating beds to reduce excess nutrients before use in shrimp ponds. Floating beds can also be used in wastewater ponds before discharge into the environment.
Sludge disposal – Mud and waste from culture ponds are pumped and stored on land which resembles a salt marsh. Here crops can be cultured with conventional land-based techniques.
Culture ponds – Ponds can produce up to 8 tons of shrimp per 1,000m2. The amount of waste discharged can reach up to 700kg of nitrogenous wastes and 200kg of phosphorous wastes.