Managing vegetated water harvesting structures: effect of vegetation management on infiltration for better drought resilience in mediterranean agroecosystems

Runoff and infiltration partitioning directly impact water resource conservation in arid agroecosystems, affecting both cultivated lands and uncultivated zones like ditches, channels, and grass strips. A deeper understanding of soil infiltration capacity variability is needed, which requires unraveling the complex interactions between soil, vegetation, and management practices. The study aimed to explore how quasi-steady ponded infiltration rates of a fluvisol soil change over time under different conditions: bare soil, various cover crops (a Malvaceae species with a taproot system and a Poaceae species with a fibrous root system), and vegetation management techniques (burning, mowing, and chemical weeding) typical in the vegetated water harvesting structures of Mediterranean agroecosystems. To achieve this, a modified double-ring infiltration method was employed to repeatedly measure quasi-steady infiltration, fcp, at the same location over time. Conducted on a 64 m² plot with measurements spaced at least 30 cm apart, the setup enabled assessment of variability within the plot. Findings indicated that bare soil had a significantly lower fcp compared to covered soil, with Malvaceae cover showing double the fcp of Poaceae cover. Seasonal variation was evident, with the highest fcp in summer and the lowest in winter. The study highlighted strong spatial variability in fcp along a short transect and found no significant impact of management practices compared to the vegetated control. These results emphasize the importance of considering plant characteristics and seasonal factors in assessing NBS effectiveness for quasi-steady ponded infiltration rates, rather than focusing solely on vegetation management strategies.