Pedogeological field walks within the university campus as a strategy to incorporate urban soils to the curricula of various degree programs

Purpose Soils fulfill essential ecological functions, but society and future professionals involved in managing soil resources remain largely unaware of these. Walking across the university campus becomes a safe, cost-effective, and pedagogically rich alternative for teaching soil science through immersive field experiences, and especially if budget constraints and security for long-distance fieldwork limit extended multi-day field trips. In response, we developed a set of 3 structured pedogeological walks with the aim to introduce students of several degree programs (urbanism, architecture, biology, geosciences, etc.) to natural and artificial urban soils, to highlight their ecosystem functions and services, and to promote awareness of the pedogeodiversity and variability. Methods We designed three pedogeological paths within Ciudad Universitaria -the main campus of the Universidad Nacional Autónoma de México- by integrating cartographic analysis, interviews and field observations. Criteria for path allocation included the diversity of geologic materials, soils and land-uses. The proposed routes were tested with professors and students, and observation points were established to enable educational activities. Results A land use map of the campus (730 ha) was generated, delineating i) undisturbed areas (original ecosystems on lava flows), ii) modified green areas (sport fields, recreational areas, growing grass lawns for soccer fields, and rewilded areas), and iii) areas covered by urban infrastructure (roads, parking lots, hardscape and buildings). Three natural soils were included in the pathways: on recent lava flows: Nudilithic Leptosols and Terric Phaeozems, and Paleosols underlying the lava flow. The pathways also include human altered areas with Technosols developed from diverse anthropogenic materials (urbic and spolic Technosols) and sealed surfaces (Ekranik Technosols). Each route requires approximately one hour to complete, although it can be extended to incorporate thematic activities or guided discussions at key observation points. Conclusion Walking-based methodologies facilitate scientific observation, promote environmental awareness and interdisciplinary learning. They are useful to train professionals from various disciplines in proper management and preservation of urban soils in volcanic cities and in sustainable city planning.