A Magnifying Glass on Biochar Strategy: Long-Term Effects on the Soil Biota of a Tuscan Vineyard

Biochar application to soil is one of the techniques proposed to reduce the adaptive stresses of crops to climate change in the Mediterranean area and sequester carbon in the soil. Biochar application is irreversible and, once applied to soil, persists for centuries. This study aimed to scale up from laboratory to field application data of biochar effect on soil biota and to evaluate the conjoint use of soil microarthropods and ants as bioindicators. The experimental site is part of the Long-term Experiment Platform (LTEP) and is a Tuscan vineyard. Biochar was applied to the soil at two doses (22 t ha−1 and 44 t ha−1). Ten years after the biochar application, we analyzed soil properties and biological quality. We assessed the importance of microarthropods and ants as bioindicators to quickly detect the effectiveness, benefits, or threats to soil biodiversity and quality over a long period. The results show that the response of different groups of invertebrates varies. Microarthropods and ants may have distinct turnover patterns and be differently affected by biochar. We applied some biological indices, and the soil quality index based on microarthropods (QBS-ar) showed a significant response with higher biological quality related to the single dose of biochar. Our result underlines how biochar can combine soil protection with carbon sequestration and Mediterranean crop management. A single biochar application promotes the increase of soil biological quality. The application and validation of biological indicators in biochar field studies is a strategy to impart helpful information for environmental safety and support agronomic policies, decision-makers, and regulatory bodies.