Suchergebnisse

The combination of tree and pasture production has been recently promoted by the European Union as an agroforestry system type. Pasture production under trees produces annual farm outputs which promote long term rural population stabilisation compared with exclusively forest systems. At the same time, the presence of a tree increases the long term value of the land. The objective of this study was to evaluate the effect of two different tree densities, seed mixtures and fertilization on annual meadow production after 9 years of a silvopastoral system. The tree species was birch (Betula alba L.) established at two densities (2500 and 833 tree ha–1). Fertilization regimes included no fertilization and mineral inputs. Initial seed mixtures included cocksfoot (Dactylis glomerata) and perennial ryegrass (Lolium perenne) together with white and red clover (Trifolium repens and T. pratense). The results showed a significant effect of fertilization, seed mixture and tree density on meadow production. Meadow production was not reduced over time in spite of tree canopy development, which makes birch more suitable for meadow production when compared with radiate pine (Pinus radiata). Fertilization had a major effect at the start of the experiment in terms of modifying annual meadow production. However, by the end of the experiment its effect was modified by tree density and previous seed mixture.

Sewage sludge use in agriculture is promoted by the European Union since the normative of cleaning waters related to the compulsory use of depuration plants in all cities over 2000 inhabitants was finally implemented in 2005. The University of Santiago de Compostela (USC) has been conducted long-term experiment research about the application of different sewage sludge doses in silvopastoral systems. Main results shown that sewage sludge can be successfully used as fertilizer for both tree and pasture development, with reduced toxicity for animals when plant production is considered in both very acidic and acidic-neutral soils. This paper provides an overview of the main findings in acidic soils of the long-term results after application of sewage sludge in soils.