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| Titel |
Spatial and temporal soil water variability in the plowing horizon of agriculturally used soils in two regions of Southwest Germany |
| VerfasserIn |
Maxim Poltoradnev, Joachim Ingwersen, Thilo Streck |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111597
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| Publikation (Nr.) |
 EGU/EGU2015-11733.pdf |
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| Zusammenfassung |
| Soil water dynamics plays an important role in soil-plant-atmosphere interactions. There
is a lack of long-term continuous measurements of topsoil water content at the
regional scale. The objective of the present study was to quantify and elucidate the
seasonal dynamics of spatial soil water content variability in the plowing horizon (Ap)
of agricultural soils at the regional scale. The study was conducted in the central
part of the Kraichgau and the Mid Swabian Alb in Southwest Germany. In each
region a soil water network embracing 21 stations was set up. All stations were
installed on cropped agricultural sites and distributed across three spatial domains: an
inner domain 3 km x 3 km (5 stations), a middle 9 km x 9 km (8 stations), and an
outer domain 27 km x 27 km (8 stations). Each station consists of a TDT sensor
(SI.99 Aquaflex Soil Moisture Sensor, Streat Instruments Ltd, New Zealand), which
senses both soil water content and soil temperature, a rain gauge, and a remote
transfer unit (RTU, datalogger + GSM modem), which stores and transfers data
via GPRS modem to the central data server (Adcon Telemetry GmbH, Austria)
located at the University of Hohenheim. The TDT sensors were installed at 0.15
m depth. A sensor consists of a three meter long and three centimeter wide flat
transmission line. The relationship between the standard deviation (Ïăθ) of the soil water
content (SWC) and mean spatial soil water content (/¨Î¸/©) formed combinations of
concave and convex hyperbolas. However, it strongly depended on SWC state and
season. Generally, Ïăθ was found to be changing along a convex trend during dry
out and rewetting phases with a maximum in the intermediate SWC range. At the
rain event scale, Ïăθ(/¨Î¸/©) was either ascending or converging with decreasing /¨Î¸/©.
A concave shape was observed when /¨Î¸/© approached to dry state. The majority
of Ïăθ(/¨Î¸/©) hysteresis loops were observed in intermediate and intermediate/wet
state of SWC. All hysteretic loops were clockwise oriented. Rainfall intensity and
distribution were identified as main factors driving SWC variability at the regional scale. |
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