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Leaching of macronutrients such as nitrogen, phosphorus and potassium from soils is of particular interest in the Baltic Sea region because of its adverse effects on water quality. The objective of this study was to evaluate macronutrient leaching in a juvenile hybrid aspen (Populus tremula L. × P. tremuloides Michx.) plantation cultivated in an agroforestry system and fertilized with biogas production residues, wastewater sludge and wood ash in hemi-boreal climate conditions. Analysis of macronutrient concentrations in the soil solution showed that annual macronutrient leaching decreased over time after the establishment of the plantation and application of fertilizers. Moreover, macronutrient leaching was affected not only by meteorological conditions, but also by the type of fertilizer used. During the five years after establishment of the plantation, nitrate-nitrogen leaching decreased up to 99.6%, phosphate-phosphorus leaching decreased up to 97.1%, but potassium ions leaching decreased up to 76.5%. Nevertheless, juvenile hybrid aspen plantations cultivated in an agroforestry system remain an important part in mitigation of leaching of macronutrients from agricultural lands in the Baltic Sea region. [ABSTRACT FROM AUTHOR]

An integrated model system has been developed to estimate the impact of nitrogen reduction measures on the nitrogen load in groundwater and in river catchment areas. The focus lies on an area-wide, regionally differentiated, consistent link-up between the indicator "nitrogen balance surplus" and nitrogen charges into surface waters. As a starting point of the analysis actual nitrogen surpluses in the soil were quantified using the agro-economic RAUMIS-model, which considers the most important N-inputs to the soil and N-removals from the soil through crop harvest. The most important pathways for diffuse nitrogen inputs into river systems are modelled with the water balance model GROWA. Additionally, the time-dependent nitrogen degradation along the nitrogen pathways in soil and groundwater are modelled using the WEKU- model. The two selected river basins in Germany cover a variety of landscape units with different hydrological, hydrogeological and socio-economic characteristics. The results indicate a wide range of annual nitrogen surpluses for the rural areas between than 10 kg N ha-1⋅a-1 and 200 kg N ha-1⋅a-1 or more, depending on the type and intensity of farming. The level of nitrogen inputs into the surface waters is reduced because of degradation processes during transport in soil and groundwater. Policy impact analyses for a nitrogen tax and a limitation of the livestock density stress the importance of regionally adjusted measures. [ABSTRACT FROM AUTHOR]

Soil and surface water along roads are exposed to pollution from motorways. The main pollutants are polycyclic aromatic hydrocarbons (PAH), mineral oil, heavy metals and salt. These pollutants originate from vehicles (fuel, wires, leakage), wear and degradation of road surfaces and road furniture (i.e. crash barriers) and the application of de-icing salts. Runoff, vehicle spray and dry deposition disperse these contaminants into the soft shoulder (verges) of the roads and surface water to a measurable distance of about 50 up to more then 150 m from the road. Despite many monitoring programs, little is known about the risks of this diffuse pollution for soil and water quality and the geochemical and physical factors which determine these risks. Also little is known about the effects of possible measures. Therefore, extensive research has been carried out at two local motorways. Specific measurements on runoff, vehicle spray and effects of measures have been carried out for one year (13 months). This resulted in several new insights. The pollutants appear to adsorb effectively to natural soils. In vulnerable areas groundwater can be protected by adjusting the policy to removing the contaminated upper topsoil of the verges. Discharges of runoff into local surface water are not recommended. [ABSTRACT FROM AUTHOR]

In the Netherlands the leaching of heavy metals from metal building and constructing materials results in serious contamination problems in the water system. The most common sources of these heavy metals in construction materials are copper waterworks and roofs, zinc roofs, gutters and rain pipes, zinced steel, stainless steel, and lead sealing material. In urban waters the surface water and sediment standards are often exceeded. Although building and construction materials are certainly not the only source of heavy metals, they are an important part of the problem. This article focuses on six instruments that are in use in the Netherlands to try to reduce impact on the surface waters. In addition to this, national as well as international, a reconsideration of the risks and surface water standards for several heavy metals is considered. A balanced use of instruments can be considered as the application of a best practice. [ABSTRACT FROM AUTHOR]