Phosphorus fractions in preferential flow pathways and soil matrix in hillslope soils in the Thuringian Forest (Central Germany)

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Abstract

Phosphorus (P) is primarily transported in soil through preferential flow pathways (PFP), which can rapidly move water and matter bypassing large portions of the soil. This study investigated the composition of P forms in PFPs and soil matrix in two profiles at a forested hillslope in the Thuringian Forest (Central Germany), in order to evaluate (1) the effect of PFPs on the distribution of P fractions in forest soils, and (2) how hillslope position influences P fractions and other chemical parameters. To characterize water and mass fluxes in the profiles, flow pathways were visualized using dye tracer experiments. Stained and unstained soil material was sampled to assess differences of chemical parameters in the PFPs and soil matrix, and tested for correlations between chemical parameters to determine the factors influencing P fractions in soils. The results revealed significantly higher P contents (total P and most P fractions) in the upslope profile compared to the downslope profile. This accumulation effect in the upper profile was also observed for C, N, Fe, and Mn. The distribution of flow patterns also differed between the two profiles with stronger vertical infiltration into mineral soil and more preferential flow along stones and roots in the upslope profile compared to the downslope profile. However, the observed difference could not be addressed to hillslope effects as both test plots were located in mid-slope position, but were strongly influenced by spatial heterogeneity (e.g., micro-relief). Furthermore, no statistically significant accumulation effect of P or other elements in PFPs compared to soil matrix was found. At the test site, the combination of high stone content with low potential for P sorption, and predominance of near-surface lateral flow, appears to have hampered the development of gradients in chemical parameters between PFPs and soil matrix.

Details

Original languageEnglish
Pages (from-to)407-417
Number of pages11
JournalJournal of Plant Nutrition and Soil Science
Volume180
Issue number3
Publication statusPublished - Jun 2017
Peer-reviewedYes

External IDs

ORCID /0000-0001-8948-1901/work/168717641
Scopus 85014729691

Keywords

ASJC Scopus subject areas

Keywords

  • Forest soil, Hillslope processes, PFP, Phosphorus fractions, Preferential flow