The STEP-Awbh Space-Time Model for Digital Soil Mapping.

In the Anthropocene, processes and response feedbacks to soil-ecosystems have accelerated, jeopardizing the sustainability of the soil resource at local, regional, national, and global scales. Soil-ecosystems are at the heart of the critical zone and sustain life on Earth by providing a quasi non-renewable resource that, once degraded, is extremely slow to restore. Yet global change, such as population growth, climate change, and drastically altered land use, imposes profound imprints onto soil-ecosystems impacting soil quality, biodiversity, and food security. Questions emerge about the role of digital soil mapping (DSM) in the context of a changing world. Implementations of contemporary digital soil models have emphasized mapping of soil-forming or SCORPAN factors assuming that they are more or less static to infer on soil properties or classes. This perspective is constraining and does not capture soil evolution, i.e., the change of soil properties and their environmental co-variates through time. We have proposed to enhance conceptual soil models to explicitly incorporate the soil-ecosystem evolution and anthropogenic forcings into the modeling process. Our space-time modeling framework, called STEP-AWBH (“step-up”), consists of soil (S), topographic (T), ecological (E), geologic (P), atmospheric (A), water (W), and biotic properties (B) as well as human-induced forcings (H) to predict pixel-based soil properties or behavior. We will discuss how contemporary DSM can be expanded to enhance capabilities to respond to grand challenges we face at global scale linked to sustainability, vulnerability, adaptability, and risk assessments of soil-ecosystems across multiple spatial and temporal scales.