5. CONCLUSIONS
Agricultural practices change the hydrophysical properties of páramo soils that are associated to the hydrological service of streamflow buffering. The information shown in this paper represents an understudied ecosystem, dry páramos, that differs from the more studied humid páramos. It shows that changing natural vegetation to potato crops, onion crops and later, livestock, leads to a reduction in soil organic matter and water content and an increase in bulk density, especially at the surface level. This trend was evidenced by the decline of these variables in the areas transformed to fallow soil. Furthermore, páramo soils under anthropic uses showed higher variability in these hydrophysical properties with rainfall seasonality.
Activities such as ploughing, agrochemical use and irrigation influenced the hydrophysical properties of the páramo soils under onion crops, where the gradient on the hydrophysical properties according to depth –typical of natural areas– disappeared. In addition, substantial changes in pH and electric conductivity were observed. Even if irrigation contributes to preserve water content, and frequent fertilization provides organic matter, the organic matter content decreases in the long-term with extended cultivation. Furthermore, as the soil hydrophysical properties are severely compromised, this leads to the abandonment of these lands and their conversion to fallow.
The increase in bulk density, electric conductivity and the reduction in organic matter could impair the ability of páramo catchments for streamflow buffering. This will increase surface runoff and reduce base flow, which worsens the capacity of páramo catchments to maintain steady flows and allow multiple water uses. It is extremely important to develop strategies that can communicate this information to decision-making institutions and farmers aiming at a collaborative search of best practices that provide opportunities to harmonize people´s livelihoods with environmental conservation of páramos and of the ecosystem services dependent on them.