Nutrient budgets in a dry heathland watershed in northeastern Spain

Abstract

Abstract. Dissolved nutrient inputs in bulk precipitation and outputs in streamwater were measured during 3 years of contrasting hydrological conditions in a 6.3-ha, grazed heathland watershed on schists in the Montseny mountains (NE Spain), drained by an intermittent stream. On average, 39% of the precipitation became streamflow. Bulk precipitation delivered positive net alkalinity (mean 0.22 keq/ha/yr), sulphate input was moderate (9.0 kg SO,-S/ha/yr), and the mean input of inorganic N was not exceptionally high (6.6 kg/ha/yr). Ion concentrations were relatively low in streamwater; SOd2-was the dominant anion. Most concentrations in streamwater varied seasonally, with maxima in late summer or early autumn and minima in spring. This pattern probably resulted from increased availability of ions for leaching due to decomposition of organic matter and chemical weathering during the warm period. Nitrate concentrations were relatively high in winter and dropped sharply in early spring, probably because of biological uptake. Annual element outputs in streamwater varied between years and seemed to be controlled by both the amount of annual streamflow and its seasonal distribution. Annual inputs exceeded outputs for dissolved inorganic N. The watershed accumulated H+ and Ca*+, had net losses of Na+ and Mg'+, and was close to steady state for K+, SO,'-, Cl-and alkalinity. The chloride budgets gave no evidence of substantial dry deposition in this system. The cationic denudation rate was negative (-0.14 keq/ha/yr) because Ca*+ retention was higher than net exports of Na+ and Mg?+ from silicate weathering. Low nutrient export and little production of alkalinity suggest that this watershed has a low buffering capacity.

Nutrient cycling in deciduous forest ecosystems of the Sierra de Gata mountains: nutrient supplies to the soil through both litter and throughfall

“…Nitrogen values are very similar to those reported by Likens et al [22] and Belillas and Roda [3], and clearly lower than those found in industrialized areas [7,48].…”

Responses in Soil Carbon and Nitrogen Fractionation after Prescribed Burning in the Montseny Biosphere Reserve (NE Iberian Peninsula)

“…Bedrock is a metamorphic schist where the major minerals are quartz albite, muscovite and chlorite. Soils are acidic, with a pH of 4.5 to 5.5, and characterised by a sandy-loam texture [31]. The topographic location and humidity circulation lead to a general situation that favors the presence of Atlantic vegetation, where the shrubs Erica scorparia L., Erica arborea L. and Calluna vulgaris L. are widespread.…”

Hydrogeochemical balance of forest umbrisol profiles (‘Sierra de Gata’, central western Spain)

“…Forest nutrition tends to optimize the resources (e.g. macro-and micro-nutrients), producing an effective recycling (Binkley and Richter, 1981;Belillas and Rodá, 1991;Iwata et al, 1995;Likens et al, 1997;Vitousek and Farrington, 1997). As an example, Gallardo et al (1999) have studied the nutrient efficiency of the oak coppices in a rainfall transect at the Sierra de Gata Mountains; they concluded that the nutrient efficiency depends directly on the amount of annual rainfall in those forests.…”