TITLE:
Headwaters Deforestation for Cattle Pastures in the Andes of Colombia and Its Implications for Soils Properties and Hydrological Dynamic
AUTHORS:
Guillermo Vásquez-Velásquez
KEYWORDS:
Forest Influences, Deforestation, Soil Compaction, Headwaters
JOURNAL NAME:
Open Journal of Forestry,
Vol.6 No.5,
August
31,
2016
ABSTRACT: Deforestation of headwater in the Andes of Colombia is a historical
process that has its origins in pre-Hispanic communities and in nineteenth and
twentieth centuries, intensified by settlers and farmers. These lands have been
intended mainly to pasture cattle. Soil compaction, caused by the trampling of
cattle, was evaluated in soils derived from volcanic ash (Andisols), with
reference to values found for variables in undisturbed natural forests in the
same region. The compared parameters were bulk density (Db), total porosity (α),
soil resistance to penetration (Rp)
and pore size distribution, analyzed by water retention curves (WRC). The
grazed soils had significant differences with respect to the natural forest
reference values: Db was 53.7%
higher, α was reduced by 11.0% and Rp in the first 7.5 cm of the top soil
was more than double, with an average increase of 275.2 to 527.2 kPa. The
analysis indicated that compacted soils had relatively uniform reduction in
distribution of macro, meso and micropores. It was concluded that deforestation
followed by pasture land destination in steep headwaters generates significant
compaction processes that can affect the infiltration, percolation and soil
water storage, which would have important hydrological implications:
augmentation of surface runoff and soil erosion, decreased the base flow and
increased direct runoff. For this reasons, it is considered that forest
restoration of headwaters is important for the maintenance of hydrological
functions of large river systems.