Dissolution of Silicon from Soilless Substrates and Additives

Silicon (Si) is a beneficial element that usually ample in mineral soil solution, but it minimally bioavailable from soilless substrates. Several Si additives are commercially available, the rate of dissolution not well-characterized. The ideal additive would steadily release over crop lifecycle. We report long-term (120 days) substrates and substrate additives. Studies involving gently agitated containers with deionized water indicated perlite, sphagnum peat, vermiculite, coconut coir released less than 0.03 mmol per liter day. Rice hulls wollastonite (CaSiO 3 ) had 7- to 130-times faster rates this system; therefore, they were further studied peat-based media. Dissolution addition 1 g peat peaked at day 10 2.1 media leaching event (15% by volume); then, gradually decreased 120 days. peak amended 12% rice was similar, increased time. concentrations nine heavy metals plant tissue compared untreated control plants determine steel slag. concentration some elements statistically increased, all well below legal limits these for human consumption United States. These results indicate both up 4 months; good sources container-grown crops