The effect of changes in natural and anthropogenic deposition on modelling recovery from acidification

International audienceThe multi-layer dynamic soil chemistry SAFE model was used to study the dynamics of recovery in the F1 catchment at Lake Gårdsjön, Sweden. The influence of (1) sulphate adsorption, and (2) changes in marine deposition, on model predictions of recovery was studied. Sulphate adsorption/desorption in SAFE is modeled by an isotherm in which sulphate adsorption is dependent on both the sulphate concentration and the pH in the soil solution. This isotherm was parameterised for the B-horizon of F1 for the sulphate concentration range 10?260 m mol-1 and the pH range 3.8?5.0. Sulphate adsorption/desorption as the only soil process involving sulphate is adequate to predict sulphate in run-off at F1. Adding the process caused time-delays in sulphate concentration in run-off of only 1-2 years, which was much shorter than previously seen in the adjacent G1 catchment. The location of Lake Gårdsjön, approximately 15 km inland from the Swedish west coast, ensures that the marine deposition to the area is high. Model output showed that the temporal variation in marine deposition has a considerable impact on the run-off chemistry. Such changes in marine deposition are difficult to foresee and their influence on modelled run-off chemistry can be large when soils start to recover as the previously high concentrations of anthropogenic sulphate in the soil solution decrease. Keywords: climate change, dynamic modelling, run-off chemistry, sea-salt effect, soil and water acidification, sulphate adsorptio

Projecting Regional Patterns of Future Soil Chemistry Status in Swedish Forests using SAFE

As part of the Abatement Strategies for Transboundary Air Pollution (ASTA) research program, the dynamic soil chemistry model SAFE was used to make hindcasts and future projections of soil solution chemistry for 645 Swedish forest soils between 1800 and 2100. The data needed were derived from different databases of different spatial resolution ranging from site-specific measurements of soil and stand characteristics from the Swedish Forest Inventory to species-specific nutrient content ranges based on literature surveys. The time-series of nutrient uptake and atmospheric deposition needed were created using the MAKEDEP model and the future scenarios were based on the 1999 Gothenburg protocol. The version of MAKEDEP used included nutrient content elasticity, and the modelled biomass nutrient content thus varies between regions as well as over time. The results were analysed by dividing the sites into three different regions (southwest, central and north) as well as nationally. It was shown that acidification remains a severe environmental problem in the southwest region even after implementation of the 1999 Gothenburg protocol, whereas in the north the problem is far less pronounced

MAGIC, SAFE and SMART model applications at Integrated Monitoring sites: effects of emission reduction scenarios

Three well-known dynamic acidification models (MAGIC, SAFE, SMART) were applied to data sets from five Integrated Monitoring sites in Europe. The calibrated models were used in a policy-oriented framework to predict the long-term soil acidification of these background forest sites, given different scenarios of future deposition of S and N. Emphasis was put on deriving realistic site-specific scenarios for the model applications. The deposition was calculated with EMEP transfer matrices and official emissions for the target years 2000, 2005 and 2010. The alternatives for S deposition were current reduction plans and maximum feasible reductions. For N, the NOx and NHy depositions were frozen at the present level. For NOx, a reduction scenario of flat 30% reduction from present deposition also was utilized to demonstrate the possible effects of such a measure. The three models yielded generally consistent results. The Best prediction-scenario (including the effects of the second UN/ECE protocol for reductions of SO2 emissions and present level for NOx-emissions), resulted in many cases in a stabilization of soil acidification, although significant improvements were not always shown. With the exception of one site, the Maximum Feasible Reductions scenario always resulted in significant improvements. Dynamic models are needed as a complement to steady-state techniques for estimating critical loads and assessing emission reduction policies, where adequate data are available

Integrated assessment modelling of air pollution in four European countries

The integrated assessment modeling on acid rain has incorporated several related effects and pollutants into a multi-pollutant/multi-effect approach, resulting in complex integrated models and policy assessments. The development and implementation of effects-oriented cost-effective emission reduction strategies in Europe are based on integrated assessment models. The project on national integrated assessment modeling in Finland, Denmark, Spain and Sweden aimed to support the national evaluation of European emission reduction strategies. The tasks covered the comparison of inventories and projections for emissions of sulfur, nitrogen oxides, ammonia and volatile organic compounds, assessment of control techniques and related costs, concentration and deposition scenarios to estimate environmental effects of acidification, eutrophication and ground-level ozone and their temporal aspects, uncertainty analyses on both individual modules and whole integrated models, and dissemination of results to stakeholders. The integrated assessment modeling provided a consistent framework for the harmonization of input data and in-depth scientific research tasks on emissions, pollutant loading and impacts including comprehensive uncertainty analyses, and facilitated the dissemination of knowledge to policy-makers

Assesing nutrient sustainability of forest production for different tree species considering Ca, Mg, K, N and P at Björnstorp Estate, Sweden

An assessment of nutrient sustainability has been done for stands of European beech, Sycamore maple, European oak, Norway spruce, Larch, Grandis fir and Douglas fir at Bjornstorp Estate in southern Sweden. To estimate the nutrient sustainability, mass balance was calculated with respect to Ca, Mg, K, N and P. The release from mineral weathering was calculated using the PROFILE model. The leaching has been estimated from observed soil water concentrations and nutrients removed by harvest from projected production. The results indicate that the planned production is on the limits of sustainability and sometimes in excess of it. The stands will overuse Ca, sometimes also Mg, K and P, if all growth is harvested. Soil acidification is still progessing at Bjornstorp Estate, and soil depletion is the result of this. The estimated sustainable yield and the mass balances suggest that the leaching rate is the most uncertain factor for assessing sustainability. Different types of critical loads were investigated, including a new type, based on no excess acidity in the system. The calculations stress the importance of reducing the acid deposition and that nutrient sustainable management must be included in forest management