title: Soil chemistry and fertility alterations in response to N application in a semiarid Mediterranean shrubland.
abstract: N deposition is currently affecting nutrient cycling in terrestrial ecosystems. We studied the effects of four years of N application (0, 10, 20 and 50 kg N ha(-1) year(-1)+background deposition) on soil chemistry and fertility in a semiarid shrubland in central Spain. Soil pH and nutrient availability fluctuated seasonally. The inorganic-N fraction in soil was dominated by nitrate, as expected in calcareous soils. N application increased inorganic N availability in soil. There was a negative correlation between N application and soil K(+) availability and pH, measured as the % change after four years. Soil N and C storage (evaluated as the % change) slightly increased after four years. Our data suggest that, in the short-term, the seasonality of nutrients overwhelm any chemical alteration related to N deposition. However, the potential implication of continuous N addition on soil chemistry in the long-term is not well understood.
authors.affiliation: Museo Nacional de Ciencias Naturales, Consejo Superior de Investigaciones Científicas (MNCN-CSIC), Madrid, Spain. raul.ochoa@mncn.csic.es
authors.forename: Raúl
authors.initials: R
authors.lastname: Ochoa-Hueso
authors.forename: Carly J
authors.initials: CJ
authors.lastname: Stevens
authors.forename: María J
authors.initials: MJ
authors.lastname: Ortiz-Llorente
authors.forename: Esteban
authors.initials: E
authors.lastname: Manrique