Effects of biochar-based seed coating binders on seed germination and radicle extension

Biochar, which is derived from biomass through a pyrolysis process, has proven to have beneficial effects on seed germination and radicle extension. Biochar-based seed coating technologies may have the potential to substitute direct seeding for large-scale vegetation restoration applications. Binders serve as “adhesives” during the biochar-based seed coating process, and the selection of appropriate binders may facilitate the positive effects of biochar on seed growth. This study examined the effects of nine binders on the seed germination and radicle extension of four plant species including radish (Raphanus sativus), lettuce (Lactuca sativa), coreopsis (Coreopsis lanceolata), and white birch (Betula papyrifera). The results indicated that certain binders performed best on various species for seed germination and radicle extension, in terms of non-phytotoxicity. The results also suggested that bio-based compounds and starch performed optimally in terms of non-phytotoxicity, which might be applied for further investigations into biochar-based seed coating technologies