Spatially resolved soil solution chemistry in a central European atmospherically polluted high-elevation catchment

Abstract

Abstract. We collected soil solutions by suction lysimeters in a central European temperate forest with a history of acidification-related spruce die-back in order to interpret spatial patterns of soil nutrient partitioning, compare them with stream water chemistry and evaluate these parameters relative to concurrent loads of anions and cations in precipitation. Five lysimeter nests were installed in the 33 ha U dvou loucek (UDL) mountain catchment at different topographic positions (hilltops, slopes and valley). Following equilibration, monthly soil solution samples were interrogated over a 2-year period with regard to their SO42-, NO3-, NH4+, Na+, K+, Ca2+, Mg2+ and total dissolved Al concentrations, organic carbon (DOC) and pH. Soil pits were excavated in the vicinity of each lysimeter nest to also constrain soil chemistry. For an estimation of phosphorus (P) availability, ammonium oxalate extraction of soil samples was performed. Cation exchange capacity (CEC ≤58 meq kg−1) and base saturation (BS ≤13 %) were found to be significantly lower at UDL than in other monitored central European small catchments areas. Spatial trends and seasonality in soil solution chemistry support belowground inputs from mineral-stabilized legacy pollutants. Overall, the soil solution data suggest that the ecosystem was still chemically out of balance relative to the concurrent loads of anions and cations in precipitation, documenting incomplete recovery from acidification. Nearly 30 years after peak acidification, UDL exhibited similar soil solution concentrations of SO42, Ca2+ and Mg2+ as median values at the Pan-European International Co-operative Program (ICP) Forest sites with similar bedrock lithology and vegetation cover, yet NO3- concentrations were an order of magnitude higher. When concentrations of SO42-, NO3- and base cations in runoff are compared to soil pore waters, higher concentration in runoff points to lateral surficial leaching of pollutants and nutrients in excess than from topsoil to subsoil. With P availability being below the lowest range observed in soil plots from the Czech Republic, the managed forest ecosystem in UDL probably reflects growing inputs of C from regenerating vegetation in the N-saturated soil, which leads to P depletion in the soil. In addition, the observed spatial variability provides evidence pointing to substrate variability, C and P bioavailability, and landscape as major controls over base metal leaching toward the subsoil level in N-saturated catchments.

Foliage Biophysical Trait Prediction from Laboratory Spectra in Norway Spruce Is More Affected by Needle Age Than by Site Soil Conditions

“…On the other hand, UHL and LYS exhibited high exchangeable acidity, and low base cations due to Ca-poor granite bedrock [86]. The UDL catchment was seriously affected by air-pollution, which caused forest decline in the past, and forest management interventions, particularly the application of dolomitic limestone between 1980 and 2007 [87], were most pronounced there. As a result, UDL catchment, naturally underlined by a Ca poor bedrock (orthogneiss) exhibited relatively low exchangeable acidity and high base saturation in the forest floor.…”

Controls on δ26Mg variability in three Central European headwater catchments characterized by contrasting bedrock chemistry and contrasting inputs of atmospheric pollutants

“…The distance between LYS and PLB is seven km. U Dvou Loucek (UDL; Eagle Mts., northeastern Bohemia [41,44,46,47]) is characterized by low Mg inputs via bedrock dissolution, and high Mg inputs via atmospheric deposition. The UDL bedrock is formed by orthogneiss (0.36 wt.…”

“…The Mg isotope determinations were thus performed at the end of the 19-year monitoring period and six years after the last application of dolomitic limestone at UDL. Soil water at UDL was collected by suction lysimeters from the depths of 30 and 50 cm [47]. At LYS and PLB, gravitational lysimeters installed at depths of 10 and 20 cm were complemented with suction lysimeters at the Isotope composition of atmospherically deposited elements in industrial areas can, in principle, differ along the catchment slope.…”

Catchment Runoff in Industrial Areas Exports Legacy Pollutant Zinc from the Topsoil Rather than Geogenic Zn

“…The more polluted site U Dvou Loucek (UDL) is located in the Eagle Mts., northern Czech Republic. − The less polluted site Na Lizu (LIZ) is located in the Bohemian (Sumava) Forest Mts., southern Czech Republic (Figure , Table ). The areas of the UDL and LIZ catchments are 33 and 99 ha, respectively.…”

“…Both sites are equipped with a gauging station. A detailed δ 18 O-H 2 O study indicated a mean residence time of water within the UDL catchment of approximately 8 months.…”