Herbaria as repositories of past soil properties and historical soil DNA

Societal Impact Statement Soil health is fundamental to agriculture, food security, and the sustainable management of terrestrial ecosystems under ongoing climate and land‐use changes. Soil microorganisms play a key role in these processes, yet how soils and their microbial communities have changed over time in response to global environmental change remains poorly understood. The study shows that soils preserved with herbarium crop specimens constitute unique historical archives for tracking past soil conditions and microbial diversity over two centuries. Insights from historical herbarium analyses should inform sustainable agricultural practices promoting soil conservation and microbial biodiversity management, thereby supporting plant health and agroecosystem functioning.