Abstract

NOE, Laura  and  ABRIL, Adriana. Litter quality, decomposition process and soil fertility relationships in the Monte desert (Argentina). Ecol. austral [online]. 2008, vol.18, n.2, pp.181-193. ISSN 1667-782X.

Although there is abundant information on decomposition processes and litter quality in deserts, little is known about the integrated effect of both factors on soil fertility. We evaluated, in the Monte desert (Mendoza, Argentina), during one year: a) the chemical and biological quality of litter of two woody species (Prosopis flexuosa and Larrea divaricata) collected after two litter fall events (summer and autumn), b) the decomposition dynamics (weight loss and chemical compound variations) in cages of 1 cm mesh, and c) the changes in fertility of the underlying soil (beneath the cage). Litter quality differed between falling dates (summer: more cellulose, phenols and soluble N; autumn: more soluble C) and between species (P. flexuosa: more fiber, total and soluble N and less phenols), while decomposition dynamics was similar between species. In contrast, litter quality (specifically, soluble compound contents) seems to affect the magnitude of changes in the underlying soil fertility. The important decrease in soil microorganisms under L. divaricata is probably due to the high soil exposure to summer insolation. It is concluded that, during the first year, the decomposition process is weakly regulated by litter quality and that the variations detected responded mainly to the Monte climatic conditions.

Keywords : Prosopis spp; Larrea spp; Lignin; Decomposition rate; Humic acids; Soil microorganisms; Cellulolytics; Nitrifiers.

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