Biochar-based seed coating dramatically increases seedling germination and field establishment of arctic lupine (Lupinus arcticus)

Abstract: Positive effects of biochar on early plant performance suggest the potential use of biochar-based seed coatings in the context of restoration and reforestation programs. We present results of field and lab trials examining effects of biochar-based seed coatings on 8 common boreal shrub and tree species. The application of biochar coatings (using polyvinyl acetate as a binding agent) inhibited germination for 7 species (3 conifers and 4 shrubs species) but greatly enhanced seedling establishment of arctic lupine (Lupinus arcticus S. Watson), with a ~13-fold increase relative to controls. Both lab and field provided similar results. In the field trial we observed that presence of natural charcoal and mineral soil approximately doubled the chances of lupine establishment. The findings suggest that both biochars and natural fire residues act as a germination trigger for arctic lupine seeds, and also indicate the importance of species-specific effects in using biochar-based seed coating for artificial seed enhancement. To enhance the effectiveness of biochar-based reforestation strategies on direct seeding, future studies should focus on potential germination stimulants and identifying binding agents suitable for a broad range of species.摘要：生物炭（biochar）对植物早期生长的积极效应，提示其在生态修复与造林项目中可用于制备生物炭基种子包衣。本研究开展田间与室内试验，探究生物炭基种子包衣对8种北方寒带常见灌木与乔木物种的影响。以聚乙酸乙烯酯作为黏合剂制备的生物炭包衣，对其中7个物种（3种针叶树与4种灌木）的种子萌发产生抑制作用，但显著提升了北极羽扇豆（*Lupinus arcticus* S. Watson）的幼苗定植率，相较对照组提升约13倍。室内与田间试验结果一致。田间试验中，我们观察到天然木炭与矿质土壤的存在可使羽扇豆的定植概率提升约一倍。本研究结果表明，生物炭与天然火烧残留物均可作为北极羽扇豆种子的萌发触发因子，同时也证实了在利用生物炭基种子包衣开展人工种子强化时，物种特异性效应的重要性。为提升生物炭基直播造林策略的实施效果，未来研究应聚焦于潜在的萌发促进剂，以及筛选适用于多物种的黏合剂。