Effects of trees on infiltrability and preferential flow in two contrasting agroecosystems in Central America

Published on December 31, 2014 | Author: Laura Benegas, Ulrik Ilstedt, Olivier Roupsard, Jeffrey Jones, Anders Malmer

We tested the hypothesis that trees have measurable effects on infiltrability, macroporosity, and preferential flows in agrosilvopastoral systems. Managing agricultural systems for water conservation is a critical component of sustainable systems. We investigated the relationship between infiltrability and the distance to the nearest tree, and whether differences in macroporosity can account for differences in infiltrability.
In both systems, preferential soil water flows were dominant compared to matrix flow. Trees in the pasture landscape improved infiltrability and preferential flow but had no significant effect in the coffee agroforestry system. After comparing rainfall intensity and frequency data to the measured infiltrability values, we conclude that trees in the pasture system reduce surface runoff at the highest observed rainfall intensities (>50 mm h-1). The volcanic soils of the coffee plantation are less degraded and their high natural permeability has been maintained. Since the coffee plants at this site are established (40 years) perennial vegetation with substantial residues and extensive root systems like trees, they improve soil physical properties similarly to trees.

Trees increase hydrologic services in pasture lands, a rapidly expanding land use type across Latin America, and therefore may be a viable land management option for mitigating some of the negative environmental impacts associated with land clearing and animal husbandry. However, in land manage- ment practices where understorey perennial vegetation makes up a large proportion of the cover, such as for coffee agroforestry systems, the effect of trees on infiltration-related ecosystem services could be less pronounced
Benegas, L., Ilstedt, U., Roupsard, O., Jones, J. & Malmer, A. (2014). Effects of trees on infiltrability and preferential flow in two contrasting agroecosystems in Central America. Agriculture, Ecosystems and Environment. 183: 185-196.
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