The uptake and movement of toxic compounds in rice plants can reduce both yield and grain quality. In Thailand, this problem has a significant economic impact, causing losses of approximately 7,800–14,000 tons of rice per year.

Previous laboratory studies by Suksabye et al. (2015) and Treesubsuntorn et al. (2017a) showed that applying biochar and/or beneficial microorganisms can effectively reduce heavy metal levels in rice roots, shoots, and grains. Interestingly, treatments with lower heavy metal concentrations also had higher levels of essential divalent cations such as calcium (Ca), magnesium (Mg), and manganese (Mn).

These elements may help control the uptake and movement of heavy metals within the plant, resulting in lower accumulation in the shoots and grains. Based on these findings, a soil amendment rich in divalent cations is being developed and has already been applied under real field conditions in Thailand, showing promising potential for practical use.