Trees enhance soil carbon sequestration and nutrient cycling in a silvopastoral system in south-western Nicaragua
Journal article, Peer reviewed
Permanent lenke
http://hdl.handle.net/11250/2425091Utgivelsesdato
2016Metadata
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Originalversjon
10.1007/s10457-016-0049-2Sammendrag
Tree occurrence in silvopastoral systems
of Central America has been under pressure for
various reasons including attempts to improve grassland
productivity and the need for wood. However,
scattered isolated trees are also recognized to provide
ecosystem services like shade, fodder and fruits that
are important to cattle in the dry season. In addition,
trees may enhance the climate change mitigation
potential of silvopastoral systems through increased
carbon (C) uptake and subsequent soil carbon sequestration.
Through differences in plant traits like nutrient
uptake, canopy structure and litter quality, tree species
may have an effect on C and nutrient cycling. Due to a
prevailing north-easterly wind in the study area, three
distinct areas associated with the impact of tree litter
deposition were identified: (1) open pasture—no tree
litter deposition; (2) tree canopy—above and belowground
tree litter; and (3) leaf litter cone—aboveground
tree litter deposition. Furthermore, the effect of
tree species, Guazuma ulmifolia and Crescentia alata,
were considered. The presence of trees, as compared
to pasture, caused larger topsoil C, N and P contents.
In the subsoil, C content was also larger due to tree
presence. Soil fractionation showed that tree-induced
larger litter input subsequently increased free and
occluded OM fractions and ultimately increased
stabilized SOM fractions. Therefore, trees were found
to enhance soil C sequestration in these silvopastoral
systems. This is also supported by the soil respiration
data. Although the respiration rates in the pasture
subplots were lower than in the leaf litter subplots, the
difference was not significant, which suggests that part
of the extra C input to the leaf litter subplots stayed in
the soil. Nutrient cycling was also enhanced by tree
presence, but with a clear differentiation between
species. C. alata (Jı´caro) enhanced available and
stabilized forms of organic N, while G. ulmifolia
(Gua´cimo) enhanced available soil P and stabilized
organic P.