Contrasts in Top Soil Infiltration Processes for Degraded vs. Restored Lands. A Case Study at the Perijá Range in Colombia

Abstract

Governments are increasingly committing to significant ecological restoration. However, the impacts of forest restoration on local hydrological services are surprisingly poorly understood. Particularly, limited information is available about the impacts of tree planting on soil infiltration processes and runoff pathways. Thus, we investigated the saturated hydraulic conductivity (Ks) and preferential flow pathways in three land-cover types: (i) Active Restoration, (ii) Degraded Land, and (iii) Reference Forest, with contrasting differences in soil profile and land use history in the municipality of La Jagua de Ibirico, César department, Colombia. We conducted soil sampling, using the Beerkan method to determine Ks values. We also measured vegetation attributes (i.e., canopy cover, vegetation height, diameter at breast height, and total number of trees) and carried out three dye tracer experiments for each study site. The blue dye experiments revealed that near surface matrix infiltration was dominant for Degraded Land, while at the Active Restoration and Reference Forest, this only occurred at local surface depressions. The general infiltration pattern at the three land uses is indicated as being macropore flow with mixed interaction with the matrix and highly affected by the presence of rock fragments. The deeper infiltration patterns occur by preferential flow due to the presence of roots and rock fragments. The mean Ks for the Active Restoration (240 mm h−1) was much higher than the Ks at Degraded Land (40 mm h−1) but still considerably lower than the Reference Forest (324 mm h−1). These results indicate that top soil infiltration capacity and soil physical parameters not only directly regulate the amount of infiltration but also infiltration patterns and runoff processes, leading to lower infiltration and increased excess overland flow for Degraded Land than for other land uses.

Determinants of Field‐Saturated Soil Hydraulic Conductivity Across Sub‐Saharan Africa: Texture and Beyond

“…(2007) showing that tree planting in the tropics, both in afforestation and agroforestry, improves soil infiltration capacity across a wide range of conditions and humidity levels. More recent studies in the tropics further support these findings (Abaker et al., 2018; Benegas et al., 2014; Bonnesoeur et al., 2019; Filoso et al., 2017; Leite et al., 2018; Lozano‐Baez et al., 2019, 2021; Mens et al., 2023; Niemeyer et al., 2014; Nyamadzawo et al., 2007; Zwartendijk et al., 2017). The positive impacts appear due to increased litter inputs, improved soil biological activity, and enhanced aggregation and macropore formation (e.g., root and faunal channels) (Bargués Tobella et al., 2014; Belsky et al., 1989, 1993; Niemeyer et al., 2014; Zwartendijk et al., 2017).…”