Bio-cement to tackle soil salinity in Thailand

King Mongkut’s University of Technology Thonburi (KMUTT) has joined hands with the Royal Irrigation Department (RID) in a project to tackle agricultural challenges caused by soil salinity in Northeast Thailand using bio-cement. According to Thidarat Bunsri, a member of the Smart Biomaterials and Technology Research Group at KMUTT, bio-cement is developed with microbial-induced calcium carbonate. Microbes from fermented fish bone residue, a byproduct of industrial-scale fish sauce production, are used in the project as the key organic compound.

Ms Bunsri said that this bio-cement is saline resistant and, because of geopolymer technology, it can retain rainwater while preventing salt from entering. The problems of saline soil and sandy earth have long been major obstacles to healthy agriculture in the area. There is a layer of rock salt in the groundwater level and its sandy soil is unable to store rainwater.

The project's bio-cement compound includes gangues that contain silica and alumina, a microbial solution, and egg shells, which serve as food for microbes. The material is resistant to salt erosion and can repair itself from micro-cracks as the microbes will create calcium carbonate crystals to fill them.

A pilot test is now being conducted in a rice field at the Irrigation Experiment Station No 3 (Huay Ban Yang) in Muang district of Nakhon Ratchasima. In this test, bio-cement sheets, each measuring 75 centimetres x 75cm and 8.5cm thick, have been put in field lysimeters, to observe the rate of water evaporation in plants and soil.

It is also to study the bio-cement's ability to slow water absorption and prevent salt from the ground from entering the water.The test will be carried out during one rice-growing cycle, for about four months, adding the self-repair capabilities and salt resistance will be examined regularly.

"If successful, the team aims to develop a formula of bio-cement that can be used with a 3D printer, possibly to make artificial reefs or bio-concrete for construction to retain water underground," said Ms Bunsri. The project is not just a significant step forward in terms of agricultural technology, but will also contribute to environmental sustainability.