One of the most essential ecosystem services provided by high-Andean páramos is streamflow buffering. A combination of soil, vegetation and climate characteristics provides páramos with an exceptional ability to store, regulate and supply water, particularly in their natural state. However, páramo catchments are seldom pristine. Agriculture is one of the most widespread human activities in páramos and considerably affects their soil hydrophysical properties. This research assesses how soil

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... rties are affected by the conversion from natural páramo vegetation to fallow, onion, or potato crops. We measured Soil Organic Matter (SOM), Bulk density (Bd), pH and electric conductivity (EC) at three depths (0–5, 10–15 and 20–25 cm), in a stratified random survey of different land uses in the Eastern Cordillera of Colombia. Samples were collected in wet and dry seasons. Agricultural use affects all the studied properties, increasing Bd (+0.11 g cm-3), decreasing SOM (-5.5%), and increasing pH (+1.3) and EC (+187 µS cm-1). Seasonality did not have a significant effect on the studied properties under natural vegetation; however, there were significant differences between wet season and dry season in agricultural soils in SOM (-7.2% and +5.7% in fallow and potato crop, respectively) and Bd (-0.22 gr cm-3 in crops). These changes show that agriculture in páramo grasslands leads to a significant decrease in soil porosity and water-holding capacity, which affects adversely the ecosystem hydrological regulation capacity. This paper contributes to a better understanding of the complexity of Andean páramos and provide crucial information to improve soil management, a key aspect for ensuring the sustainable provision of hydrological ecosystem services offered by Andean and other mountain ecosystems.