Creating soil districts for Australia based on pedogenon mapping

• Soil districts: map units of similar soils for monitoring and legislative purposes. • An innovative method maps soil districts in Australia using the pedogenon map. • The method is adaptable across local, national, and international extents. • The number of districts is set by stakeholders based on needs and soil variability. Soil is a highly diverse natural resource crucial for the functioning of ecosystems and essential for ensuring food security, biodiversity, water quality, and climate regulation. Despite its significance, soil faces increasing degradation pressures from agriculture, urbanisation, and climate change. Previous work has classified soil into pedogenons—homogeneous groups based on soil-forming factors similarity. These maps are valuable for evaluating soil condition and anthropogenic impacts, distinguishing less affected areas (genosoils) from more impacted areas (phenosoils). However, the large number of pedogenons in a region can complicate management, monitoring, and legislation. To address these challenges, we propose a methodology for designing soil districts that: i) utilises pedogenon spatial information to create compact and contiguous soil districts, ii) groups pedogenons based on soil-forming factor similarities and geographic location, and iii) provides a set of descriptors to explain the composition and characteristics of each soil district. Applying this methodology, we created 236 soil districts from the pedogenon map of Australia, forming units that can be used for legislative and monitoring purposes depending on stakeholders’ needs. The median size of these districts is 22,000 km 2 .