Agriculture, Ecosystems and Environment 139 (2010) 618–628 Contents lists available at ScienceDirect Agriculture, Ecosystems and Environment j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / a g e e Fertilization in pastoral and Pinus radiata D. Don silvopastoral systems developed in forest and agronomic soils of Northwest Spain M. Rosa Mosquera-Losada ∗ , Nuria Ferreiro-Domínguez, Antonio Rigueiro-Rodríguez Departamento de Producción Vegetal, Escuela Politécnica Superior de Lugo, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain a r t i c l e i n f o Article history: Received 21 May 2010 Received in revised form 4 October 2010 Accepted 6 October 2010 Available online 18 November 2010 Keywords: Agroforestry Biodiversity Nitrate leaching Organic matter Phosphorous Sludge a b s t r a c t The effects of fertilization, pasture sowing and tree plantation on soil fertility and tree and pasture pro- duction can vary depending on the soil type. Tree plantation is recognized as a way to reduce nutrient leaching and increase land profitability in agronomic and forest soils, meanwhile pasture fertilization and sowing is usually associated to better pasture productivity and quality. Fertilization can be performed with mineral fertilizers, which have become expensive in recent times, or with organic fertilizers like sludge, which is being promoted worldwide. This study aims to evaluate the effects of sludge fertilization, tree planting and pasture sowing on different variables of soil (KCl-pH, cation exchange capacity, total N, total and Mehlich P, nitrate and soil organic matter) and pasture (production, botanical composition, crude protein and P concentration) in treeless and agroforestry systems established in forest and agro- nomic soils. The experimental design was a randomized block following an incomplete factorial design with three replicates and nine treatments including two types of soils (forestry and agronomic), two types of vegetation (natural and sown), two types of fertilization (sludge fertilization and mineral fertilization, with a no fertilizer control) in afforested and treeless pastures. Pasture production and quality was better under agronomic soils,which also had higher levels of KCl-pH,cation exchange capacity, nitrate,total N and P than forest soils.Tree establishment did not modify nitrate or P leaching, probably due to the youth of the trees when most of nitrate was leached at the beginning of the experiment, but reduction of soil KCl pH and pasture crude protein was found in forest soils, when trees and pasture were together established, probably due to the high extractions of these systems compared with unsown forests. More- over, the sludge inputs increased pasture production better than the mineral fertilizer in the forest soils, probably due to the greater amount of nutrients applied by the former. Sowing enhanced the presence of sown grasses in the forest understory, but their presence reduced pasture quality, and they disappeared within a short period of time. Therefore, the use of the sludge as fertilizer allows nutrient recycling of this residue in soils of low fertility and increases productivity and preserves fertility compared with mineral fertilizer at short (forest soils) and medium (agronomic soils) term. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Agroforestry systems are sustainable land management tech- niques that are promoted by the EU (European Union, Council Regulation 1698/2005 [EU, 2005]) and are considered a good man- agement tool that can be implemented by farmers in the different countries of Europe (Graves et al., 2008). Monterey pine [Pinus radiata (D. Don)] is a tree species that is currently used in silvopastoral systems in temperate areas like Australia, New Zealand,and Chile (Hawke, 1991; Knowles, 1991; Benavides et al., 2009) due to its fast growth. The species is widely used in the Atlantic biogeographic region of Europe (mostly in the North of Spain and West of France) in both forestry and farm ∗ Corresponding author. Tel.: +34 600942437; fax: +34 982285926. E-mail address: mrosa.mosquera.losada@usc.es (M.R. Mosquera-Losada). grassland soils.Adequate fertilization practices in Monterey pine silvopastoral systems should be implemented to increase tree and pasture growth simultaneously at the same time that nutrient leaching risk is reduced. Recent increases in inorganic fertilizer prices along with environmental concerns have reduced the use of inorganic nitrogen fertilizers in the EU (EFMA, 2009), which are currently being replaced by organic fertilizers like sewage sludge as a cheaper nitrogen resource. In EU countries, sewage sludge production has increased since the early nineties due to the implementation of European Directive 91/271/EEC (EU, 1991), which was enacted to enhance continental water quality. Therefore, it is necessary to find an adequate means of disposal for these residues in compliance with the environmen- tal policies of the EU. One alternative that has been adopted in various countries around the world is the application of sewage sludge to soils as fertilizer ( EPA, 1994), which is regulated in Europe by the directive 86/278/EEC (EU, 1986). The use of sewage sludge 0167-8809/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.agee.2010.10.007