BENCHMARKS soil sampling protocol : Guidelines for urban systems

This document presents a comprehensive sampling protocol for a general assessment of soil health indicators (SHI) in urban systems. In addition, the protocol suggests a sampling design to address the impact of land fragmentation in an urban context. Geo-referenced sampling points are identified by random and informed sampling based on fragmentation maps generated using Sentinel 2 imagery and Landscapemetrics. 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.