Abstract

SIMOES, M. P.; NUNES, J.; GAZARINI, L.  and  MADEIRA, M.. Influence of soil placement on decomposition of leaves and stems of Cistus salviifolius L.. Rev. de Ciências Agrárias [online]. 2007, vol.30, n.2, pp.174-186. ISSN 0871-018X.

The influence of placement on litter decomposition dynamics was studied in the Mediterranean shrub Cistus salviifolius L. Litter bags containing either leaf or branch were placed at soil surface and others buried at 10 cm depth, in a Mediterranean shrubland of Alentejo, Southern Portugal. Changes in organic matter and nutrient content were assessed over a 2-year period. Decomposition was faster for leaves than for branches, as well as for buried residues than for those placed on soil surface. The annual decomposition rates, k, at surface were -0.71 for leaf and -0.17 for branches, while for buried litter they were -0.98 and -0.43, respectively. Organic matter decrease showed two phases: one initial decomposition phase of fast loss, mainly influenced by litter quality, followed by a very slow phase, influenced by both litter quality and placement. Nutrient dynamics was more influenced by litter initial chemical composition than by its placement, and the release was faster in the residues with the highest initial content, the leaves. The linear inverse relations, determined between remaining OM and N concentration in the remaining material, indicate longer N retention periods in the surface leaves than in buried ones.

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