Root architecture and hydrologic fluctuations explain spatiotemporal soil aggregation patterns

Soil aggregation is a dynamic state involving numerous biophysical interactions that cannot be deduced from snapshots of soil aggregate sizes nor the state of bulk soil organic carbon (SOC) alone. Hydrophysical and  biogeochemical functions of soil aggregation are directly linked with dynamic nature of soil aggregation. At the local scale, aggregates are formed and around particulate organic debris and they evolve as undifferentiated biogeochemical hotspots. The rate of evolution varies with the life-stage of each hotspot (the remaining reserve of C and nutrients within the hotspot) as well as the physical environmental conditions (wetness and temperature). Thus, the macroscopic patterns of hotspot (aggregate) distributions reflect the interplay between the spatial/temporal patterns of C inputs and fluctuations of physical environmental conditions. Here, we show a modeling analysis of how these aggregation patterns vary across ranges of climatic and vegetation (root architecture) conditions. We utilize a model that considers the dynamic lifecycle of ensembles of multigenerational aggregates originating from polydisperse C inputs.