C y N en suelos de pastos alpinos del macizo de Monte Perdido (Parque Nacional de Ordesa, Pirineo Central)

Jiménez, J. J., Villar, L.. C y N en suelos de pastos alpinos del macizo de Monte Perdido (Parque Nacional de Ordesa, Pirineo Central). . 2011, Vol. (bajo prensa), p. -2011.

In this study, we analysed two types of soil samples collected from 4 summits of Monte Perdido Massif (Punta Acuta, Custodia, Tobacor and Punta de las Olas). In each summit soil samples were taken in the 4 slopes oriented to the four cardinal points, at ca. 10 m below the summit point, together with a vegetation survey. We evaluated pH, nutrient concentrations, total C (inorganic + organic) and N and in the different particle size fractions after physical fractionation method, and NH4 and NO3 concentrations. Our results indicated that total C, N, P and NH4 concentrations decreased with increasing altitude, while pH increased. The highest concentrations in total C were found in the west aspect and ranged from 24.5 to 66.2 g kg-1 in Tobacor and Acuta summits, respectively. Regarding Corg concentration in the different fractions, the 53-250 μm fraction contained the lowest concentration in all aspects at Punta Acuta, while in the rest of summits the <20 μm fraction also contained the lowest Corg concentration. NH4 and NO3 concentrations varied significantly between the facets in each summit (ANOVA, P<0.05). We conclude that the combination of both abiotic and biotic factors explained our results; however, there is a need to conduct more studies to disentangle the importance of each factor in all the variables analysed.