Abstract
In the state of Baden-Wuerttemberg, Southwest-Germany, a large-scale forest liming trial was government-funded in 1983 and a lime treatment was carried out in autumn 1983 until early winter 1984. Repeated liming was applied in 2003. The limed sites and adjacent control plots were surveyed repeatedly: in 2003 before the second lime application and again in 2010 and 2015. Research of this scope presents a rare opportunity to evaluate firstly the long-term development of acidified soils with their potential for natural recovery on established control plots, and secondly the long-term effects of repeated lime application—at a collective of study sites of various growth regions and soil properties. A natural recovery in soil pH was observed since 2003, on average limited to an increase of 0.2–0.4 pH units in the forest floor and 0.1–0.3 pH units in the mineral soil until 2015. The majority of the organic layers still show very strong or extreme acidity with a pH value 3.9 on average and in the mineral soil with pH values between 3.8 and 4.6 on average. The exchangeable cations calcium and magnesium slightly increased also, although the base saturation remained <20% by 2015. The exchangeable acid cation concentrations indicated no significant changes and thus no recovery. The lime treatment greatly accelerated the rise in pH by 1.2–1.3 units and base saturation by 40–70% in the organic layer, as well as 0.3–1.2 pH units and base saturation by 7–50% in mineral soil. These effects were decreasing (yet still significant) with depth in the measured soil profile as well as with time since last treatment. Changes in soil cation exchange capacity after liming were significant in 0–5 cm mineral soil, below that they were negligible as the significant increase in base cations were accompanied by decreasing acid cations aluminum and iron (III) especially in the upper soil profile. Additionally, a decrease of forest floor and an enrichment of organic carbon and nitrogen in the mineral topsoil tended to follow liming at some sites. Overall the liming effects had a high variability among the study sites, and were more pronounced in the more acidic and coarser textured sites. Liming of acidified forest soils significantly adds to natural recovery and therefore helps to establish greater buffering capacities and stabilize forest nutrition for the future.
Highlights
Forest soils in Central Europe underwent acidification in the 20th century, which was primarily due to anthropogenic emissions of SO2 and NOX that became acidic compounds in precipitation as well as dry deposition, and depletion of organic matter from topsoil [1,2]
A complete list of parameter means as they developed over time and after lime treatment is available as Table S4 (G1) and S5 (G2) in Supplementary Materials
(p. 100), our study showed that liming greatly accelerated the rise in soil pH-H2 O compared to control plots by 0.6–2.2 units down to 10 cm topsoil and a decreasing effect with depth in the entire measured soil profile during the first 7 years since 2003 treatment
Summary
Forest soils in Central Europe underwent acidification in the 20th century, which was primarily due to anthropogenic emissions of SO2 and NOX that became acidic compounds in precipitation as well as dry deposition, and depletion of organic matter from topsoil [1,2]. Several ecological effects of the acidifying agents sulfur, nitrogen as well as ozone have been identified: harmfully affected assimilation organs of trees, damaged tree roots with declining fine root biomass, changes in ectomycorrhizal associations and in fine root distributions, magnesium deficiencies in acidified soil and nutrient imbalances due to nitrogen eutrophication [3,4,5]. Acidified soils experience a reduction in their natural acid neutralization capacity (ANC) as the pH decreases and with it the soils’ buffering range shifts [8]. For forest soils in Southwest Germany a distinct change of pH values between the years
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
