Use of carbonaceous materials for the improvement of agriculture resilience

As global population increases, new methods for more reliant seed germination will play an important role in securing enhanced agri-resilience and, hence, improved crop yields. Seed coatings are commonly used to protect and promote seed germination which often comprise impermeable polymers or microporous materials, e.g., activated carbon (AC), to adsorb chemicals.
Herein, the use of Starbons, carbonaceous mesoporous materials derived from polysaccharides, as novel seed coatings to replace AC is reported. Unlike AC, the mesoporous nature of Starbon allows for both adsorption and desorption. The physico-chemical properties of Starbons are tuneable such that their porosity and surface chemistry can be changed dependent on its carbonisation temperature.
A range of Starbons derived from alginic acid (A300, A500 and A800, where A signifies alginic acid and the three number suffix denotes carbonisation temperature) were prepared via gelation, retrogradation, solvent exchange and, subsequent, carbonisation of alginic acid. Their structural and physico-chemical properties were examined using a range of techniques followed by specific adsorption/desorption, thermodynamic and, kinetic studies with respect to three plant growth hormones (gibberellic acid (GA), indole-3-acetic acid (IAA), kinetin (KI) and one growth inhibitor (abscisic acid (ABA)). The adsorption capacity increased at higher temperatures of carbonisation and was dependent on hormone type; GA possesses a lower capacity than IAA which was attributed to its size and interaction with the surface. Kinetic studies showed evidence of a pseudo-second order rate of adsorption in all cases with a prevalence for multilayers forming in Starbon. Starbon surface area increased with carbonisation temperature due to increasing microporosity. Germination studies showed that Starbon materials improve germination rates and at a greater effect than AC.
This is the first study to show the use of Starbons as seed coatings for improved agri-resilience.