Soil solution monitoring of the Intercantonal Forest Observation Program

Since 1997 soil solution samplers are installed in certain plots of the Intercantonal Forest Observation Program Intercantonal Forest Observation Program. There solution is analysed monthly at the moment (2023) in 46 Swiss forest sites. The sites cover a uniquely broad range of Swiss forest soils, with gradients in elevation (290-1870 m), precipitation (915-2211 mm), base saturation averaged over the top 40 cm (6-100%) and total N deposition (10-81 kg ha⁻¹a⁻¹). For each site and soil depth, eight soil solution samplers (ceramic suction cup) are installed in the topsoil and five in the subsoil. Actual depths varied according to soil condition but a frequent sampling design is 20, 50 and 80 cm. Following the monthly sampling of the soil solution, the samples from the same location and from the same depth are pooled. Monthly data about following chemical soil solution indicators are measured:

  • pH and conductivity
  • Anions: Cl⁻, NO₃⁻, SO₂⁻
  • Kations: Ca²⁺, Mg²⁺, K⁺, Na⁺, Mn²⁺, NH4⁺, Altot, Alorg
  • DOC

More information about the analytical methods and results can be found in Braun & Tresch (2020). The long-term measurements of the soil solution provide the basis for revealing changes in forest soil quality. The chemical composition of the soil solution allows comparison and assessment of internationally agreed critical values and criteria on acid-base status (indicators: BC/Al ratio, pH value, N concentrations in the soil solution) as well as the leaching of N, Al and basic cations.

Funding Information:

This work was supported by:
  • Cantonal offices for forestry of the cantons AG, BS, BL,GR, SO, TG, ZH
  • Cantonal offices for environement of the cantons LU, NW, OW, SZ, UR und ZG
  • In collaboration with the Federal Office for Environment (FOEN)

Related Publications


Tresch, Simon; Braun, Sabine; Hopf, Sven-Eric (2023). Soil solution monitoring of the Intercantonal Forest Observation Program. EnviDat. doi:10.16904/envidat.366.

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Data and Resources


Field Values
DOI 10.16904/envidat.366
Publication State Published
  • Email: simon.treschfoo(at) ORCID: 0000-0003-1159-8071 Given Name: Simon Family Name: Tresch Affiliation: IAP
  • Email: sabine.braunfoo(at) ORCID: 0000-0003-4268-7659 Given Name: Sabine Family Name: Braun Affiliation: IAP
  • Email: sven.hopffoo(at) Given Name: Sven-Eric Family Name: Hopf Affiliation: IAP
Contact Person Given Name: Simon Family Name: Tresch Email: simon.treschfoo(at) Affiliation: IAP ORCID: 0000-0003-1159-8071
Publication Publisher: EnviDat Year: 2023
  • Type: Collected Date: 1997-01-01
Version 1.0
Type dataset
General Type Dataset
Language English
Location Switzerland
Content License Other (Specified in the description)
Last Updated January 27, 2023, 13:29 (UTC)
Created January 27, 2023, 09:19 (UTC)

Custom Metadata

Custom Field Values
swissFL_type infrastructure