Herbivore activity interacts with weather and vegetation to markedly affect soil condition, biotic activity, and nutrient cycling in pasture and range.  In turn, soil condition regulates the impact of environment on nutrient cycling, vegetation, herd or flock management, and animal productivity. There is a broad and deep literature on the impact of grazing on soil, but very little is available on ultra high intensity stocking (mob grazing). In this presentation, we synthesize what is known based on empirical data (e.g., responses of biotic activity and nutrient cycling to grazing frequency and intensity) and theoretical relationships (e.g., the interaction of soil texture, cover, and water content on soil compaction by domestic livestock). We then suggest research priorities and approaches to understanding how this system of grazing management influences soil physical, chemical, and biological properties and nutrient movement and utilization.