Comparing Seasonal Soil Water Storage and Flow Processes Under Different Soil Conditions

ABSTRACT Soil moisture dynamics are known to vary greatly in space and time, especially given soil–plant‐water and human interactions in agricultural environments. Knowledge gaps remain surrounding how soil moisture processes change under different soil conditions and land management practices. In this study, soil moisture storage and flow were examined over seasonal timescales in 2021 and 2022 in Southern Ontario, Canada under three soil agricultural management treatments—control (no‐till), cover cropped and compacted soil. To compare soil moisture patterns, experimental plots under each treatment (three replicates) were characterized based on vertical soil moisture distributions in the root zone (0–60 cm). Monotonic versus non‐monotonic soil moisture profiles were taken as an indication of different matrix and lateral flow pathways when field capacity was exceeded. Results showed that despite soil water storage trends being similar inter‐treatment (i.e., similar ‘average’ changes), lower water storage capacity was measured on compacted plots. Soil moisture pattern analysis revealed 95% of the study period was characterized by non‐monotonic soil moisture profiles. When monotonic patterns were identified, the control and cover crop treatments were more often associated with soil moisture that increased monotonically with depth (4% of time), attributed to better water infiltration and storage, whereas the opposite was observed for the compacted treatment. Although no dominant flow pathway could be identified for 75% of timesteps, flow pathways were more active in the spring and fall seasons, as expected, with high spatial variability of inferred instances of matrix and lateral preferential flow. Both years considered, the control and cover crop treatments each had four times more observations of capillary rise compared to the compacted treatment. The analysis of vertical soil moisture patterns therefore revealed process insights that may otherwise be overlooked when solely focusing on total soil water storage or water budget analyses.