Availability of soil phosphorus: In-situ monitoring using ion-exchange resins.

0560163 - BC 2023 RIV CZ eng A - Abstract
Tahovská, K. - Čapek, P. - Kaňa, Jiří - Choma, M. - Kaštovská, E. - Santrucková, H. - Kopáček, Jiří … Total 10 authors
Availability of soil phosphorus: In-situ monitoring using ion-exchange resins.
CONTEMPLATING EARTH: SOIL AND LANDSCAPE CONSIDERATIONS. Brno: Mendelova univerzita, 2020 - (Balková, M.; Kučera, A.; Samec, P.). (2020), s. 146-147. ISBN 978-80-7509-766-8
R&D Projects: GA ČR(CZ) GA19-16605S
Institutional support: RVO:60077344
Keywords : phosphorus availability * ion exchange resin * forest soil
OECD category: Environmental sciences (social aspects to be 5.7)

Understanding the controls over soil phosphorus (P) dynamics is crucial for identifying the possibility of ecosystem P limitation and, concurrently, for predicting risks of P losses and water eutrophication. To estimate the availability of soil P to soil biota, various extraction methods are used. Their principal disadvantage is the release of even stable and/or poorly defined soil P fractions leading to an overestimation of P availability. This imperfection is minimized using iron-based ion exchangers (IER) that continually remove phosphate from the soil solution. We tested the suitability of Fe-oxide nanoparticles based IER (Layne, USA) for measuring P availability in the field (Tahovská et al. 2016). Then, we used it to measure P dynamics in the soils of the two mountain catchments differing in their bedrocks (P-poor mica-schist., P-rich granite), and their P adsorbing abilities and exports to watercourses in ten consecutive years (Tahovská et al. 2018). Both catchments demonstrated substantial P retention (>95% of P inputs in deposition), with soil available P largely exceeding terrestrial P exports. Using ion-exchange resins, we observed higher soil P availability in the granitic catchment, which was positively related to terrestrial P export and negatively to soil P adsorbing ability. We determined the main factors affecting soil P availability dynamics in both catchments using quantitative data of long-term environmental and edaphic variables (GLMs with gamma distribution and log link function followed by a stepwise linear regression). Soil P availability was mainly controlled by the abiotic factors (throughfall chemistry, precipitation amount, litter C:P). Nevertheless, we assume that microbial processes can also drive high losses of P in the granitic catchment since the decomposition rate was the most influential variable of available P there. In conclusion, we advocate this method as a powerful predictor of P availability and P losses from various soils. It is particularly valuable in cases when site-specific conditions disqualify the use of lysimeters or estimation of terrestrial P exports using mass budget studies.
Permanent Link: https://hdl.handle.net/11104/0333171