BENCHMARKS soil sampling protocol: Guidelines for agricultural and forest experimental sites

This document presents a comprehensive sampling protocol for experimental and long-term experimental replicated sites in agricultural and forestry systems. A paired sampling design is described, focusing on the primary treatments at a site to evaluate differences in soil health indicators (SHI) resulting from applied management practices using geo-referenced points defined within each replicated plot. To evaluate soil health, a diverse set of biological, chemical, and physical SHIs is proposed. To optimize soil samples for subsequent analyses, SHI-compliant sampling protocols are implemented, aligning with the BENCHMARKS sampling scheme. For baseline site characterisation, soil samples will be collected using BENCHMARKS protocols for bulk soil, bulk density, earthworms, and mesofauna. Depending on site-specific challenges, additional samples may be collected using protocols tailored to plastic sampling or hydraulic property sampling. The document also provides detailed guidelines on sample processing, shipping, and storage tailored to each soil sampling protocol. Lastly, it outlines the SHIs recommended for assessment both in the laboratory and directly in the field.