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ABSTRACT Afforestation of abandoned agricultural lands has been the main change in land use over the past decade in Europe. However, the impact of tree species and understorey management on production and plant diversity over the medium- and long-term has not been thoroughly studied. This paper aims to evaluate the effects of an afforestation of Pinus radiata D. Don and Betula alba L. on soil pH, understorey production and plant diversity and life cycle type (annuals vs. perennials) managed with different soil fertilisation treatments over a period of 11 years. The results show an acidification of the soil 11 years after establishment, better vertical growth and diameter of pine compared with birch as usually happens in the region and important variation in the biomass production and composition of the understorey below both tree species. Understorey species remained similar during the first 5 years below both canopies. However, species richness ( S) was drastically reduced under Pinus radiata D. Don plantation compared to Betula alba L. ( Spine = 2 vs. Sbirch = 17) after 11 years of tree establishment at a very high density (2500 trees ha−1). Inorganic and organic fertilisation also caused a reduction in floristic diversity. Soil pH, pasture production and floristic understorey plant diversity are better preserved under autochthonous broadleaves, which increased the multiple uses of recently afforested lands in the short- and medium-term. In the European context of high need for sawn wood, the use of autochthonous broadleaved tree species like Betula should be promoted due to their better sustainability. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This article aims to compare the effects of applying three doses of sewage sludge, with or without liming, on organic matter, total and available chromium (Cr), and their concentration in plants. Unfertilized (NF) and mineral treatments were used as control. Soil organic-matter (SOM) modification depended on the interaction of liming and sewage sludge implementation. Liming, high sludge doses, and mineral treatment caused less SOM in the second year of study. However, after 3 years, SOM was increased by both mineral and sludge fertilizers compared to NF treatments as result of tree development and the reduction of organic-matter mineralization into the soil. These findings could have important implications for soil carbon storage capacity. Total Cr in soil and forage was increased by sewage sludge application compared to mineral or NF treatments. Liming increased Cr availability in the spring of 2000, where sewage sludge was applied, and reduced Fe availability. [ABSTRACT FROM AUTHOR]

The adequate use of sewage sludge in silvopastoral systems could enhance positive relationships between pasture and trees to increase farm incomes at medium, short and long term. The main aspects related to adequate sewage sludge use as a fertiliser are dose and timing of application, once heavy metal concentrations have been taken into account. This paper aims to evaluate the date and dose of sewage sludge applications on soil (KCl pH, soil organic matter), pasture production and tree growth after the establishment of a silvopastoral system with Pinus radiata D. Don developed on sandy soils with an initial pH of 5. It is concluded that the contribution of sewage sludge does not modify the soil conditions in a consistent manner, but cause detectable edaphic improvements depending on the climatic conditions, the results of which are manifested in enhancement of pasture and trees. The application of high doses of sewage sludge is the best option within those studied, as tree growth and pasture production tend to be increased. There are no clear effects with regard to the date of application, but if the desire is to increase pasture production during the spring season, the sewage sludge will be applied in the first of the application dates, whereas the greatest growth in the diameter of trees is produced in the plots fertilised in February, although the date of application does not appear to have a clear effect on their growth in height. [ABSTRACT FROM AUTHOR]

Silvopastoral systems in north-west Spain can reduce the risk of fires and promote multi-purpose forest land use. Fertilizer application is important for optimal pasture and tree production. The application rate of sewage sludge as a fertilizer is regulated and is based on its nutrient concentration, especially nitrogen. The aim of this study was to assess the effect of three consecutive years of application of different application rates of sewage sludge and inorganic fertilizer, with or without lime (2·5 t CaCO3 ha−1) on the ammonium, nitrate and exchangeable K, Ca and Mg contents in soil, and on the crude protein (CP), K, Ca and Mg concentrations in herbage in a silvopastoral system established under a 5-year-old Pinus radiata D. Don plantation with a density of 1667 trees ha−1. The experiment was started in autumn 1997, when a pasture mixture was sown (25 kg ha−1 Lolium perenne, 10 kg ha−1 Dactylis glomerata and 4 kg ha−1 Trifolium repens). Changes in ammonium and nitrate content in the soil in response to liming and sewage sludge application reflected the initial pH of the soil. In general, liming increased the available Ca and Mg content in soil, and CP and Ca concentrations in herbage, but reduced exchangeable K content in the soil in the first year. Application of sewage sludge increased all of the measured nutrients in both soil and herbage. [ABSTRACT FROM AUTHOR]

In recent years, in the European Union, sewage sludge production has been increased as a result of EU policy (European directive 91/271/ EEC). Organic matter and nutrient sewage sludge contents, principally nitrogen, indicate it can be used as fertilizer. The objective of the experiment was to compare the effect of no fertilization, three doses of sewage sludge, with or without liming, and the fertilization usually used in the region applied over a period of 3 years on pasture production and tree growth in a silvopastoral system. The experiment was conducted in the northwest of Spain. The soil was very acid (soil pH = 4.5) and had very low nutrient levels, especially P, that is related to site index. It was sown with a grass mixture (25 kg ha-1 of Lolium perenne L. 10 kg ha-1 of Dactylis glomerata L. and 4 kg ha-1 of Trifolium repens L.) in Autumn 1997 under a plantation of 5-year-old Pinus radiata D. Don at a density of 1,667 trees ha-1. Liming and sewage sludge fertilization increased soil pH and reduced saturated aluminium percentage in the interchange complex (Al/IC) in the soil, coming up the effect before with liming. Medium and high sewage sludge doses increased pasture production in the two first years. In a silvopastoral system, positive tree growth response to different fertilization treatments depended on tree age, initial soil fertility, soil pH, the relationship of competition with pasture production and previous liming application. [ABSTRACT FROM AUTHOR]