In: Journal of Hydrology and Hydromechanics, vol. 64, no. 2
Jörg Bachmann - Jiem Krueger - Marc-O. Goebel - Stefanie Heinze
Details:
Year, pages: 2016, 100 - 110
Keywords:
Beech forest; Soil organic carbon; Subsoil; Water repellency.
Original source URL: http://www.ih.savba.sk/jhh
About article:
Most recent studies on soil water repellency (WR) were limited to the humous topsoil or to shallow subsoil
layers slightly below the main root zone to approximately 0.5 m depth. Hence, the main objective of the present study
was to investigate the wettability pattern of a forest soil including the deeper subsoil. The selected site was a 100 years
old beech forest on a well-drained sandy Cambisol in northern Germany which showed moderate to partly extended
acidification. Results obtained from three sampling transects (3 m length, 2 m depth; sampling grid 8 × 8 samples per
transect; minimum distance of sampling locations to nearest tree about 0.5 m) show that contact angles (CA) were
always in the subcritical WR range (0° < CA < 90°). Significant impact of the tree distance on WR was not observed for
any of the transects. A prominent feature of two transects was the minimum WR level (CA < 10°) for samples with soil
organic carbon (SOC) contents around 0.25–0.4%. For the topsoils it was observed that CA increased with SOC content
from that minimum to a maximum CA of 60–75° for transects 1 and 2 with mean pH values < 3.5. For transect 3 with
slightly higher average pH close to 4.0, average CA of samples were always < 10° and showed no trend to increase with
increasing SOC content or other soil parameters like N content or C/N ratio. Subsoil samples, however, behave
differently with respect to SOC: for these samples, generally low in SOC, the CA increase with decreasing SOC occurred
at all transects for approximately 50% of the samples but did not show any clear tendencies with respect to further
parameters like texture, pH or N content. We conclude that the SOC content is the most prominent parameter
determining wettability, either positively correlated with WR for topsoils or negatively correlated for subsoil samples
very low in SOC. We finally conclude for moderately acid beech forest stands that emerging WR starts in the A horizon
after reaching a pH lower than 3.5, whereas subsoil WR might appear already at higher pH values. Even SOC contents of
∼0.01–0.02% turned out to be very effective in increasing the CA up to 70°, which points out clearly the importance of
small amounts of soil organic matter in affecting subsoil wettability. With respect to site hydrology we conclude that
ongoing acidification as well as predicted higher frequencies of extended droughts due to climate change will promote
the occurrence of WR with corresponding implications for site and catchment hydrology.
How to cite:
ISO 690:
Bachmann, J., Krueger, J., Goebel, M., Heinze, S. 2016. Occurrence and spatial pattern of water repellency in a beech forest subsoil. In Journal of Hydrology and Hydromechanics, vol. 64, no.2, pp. 100-110. 0042-790X (until 2019) .
APA:
Bachmann, J., Krueger, J., Goebel, M., Heinze, S. (2016). Occurrence and spatial pattern of water repellency in a beech forest subsoil. Journal of Hydrology and Hydromechanics, 64(2), 100-110. 0042-790X (until 2019) .