SCHRIFTENREIHE Institut für Pflanzenernährung und Bodenkunde ...

Soil water content (%)
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Chapter 4 Temporal stability of soil moisture and its application in model result validation
5 cm
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Measured Modeled TSP Rainfall
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20 cm
24-May 18-Jun 13-Jul 7-Aug 1-Sep 26-Sep
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Time (days)
Fig. 4.9. Soil moisture comparison between measured and simulated results in UG 79 during
the growing period in 2006 (Measured: measured value in field long-term monitoring site;
Modeled: modeled result based HYDRUS-1D; TSP: measured soil moisture in time stability
point).
4. Conclusions
The obtained results show that it is possible to reliably select a location to
represent the field mean soil moisture in a given area. The temporal patterns of
soil moisture were stable irrespective of water conditions. Temporal stability of
soil moisture was slightly different at the four plots due to the difference in soil
and plant properties associated with grazing effects. For the benefit of the
sampling strategy or field monitoring, the number and frequency of field
measurements could be reduced using the time stability concept. Moreover, the
choice of representativeness was verified with a covariance analysis, e.g., sand
content. This provides a method to decide one representative location with a
priori knowledge. Finally, the application of a hydraulic model (HYDRUS-1D) in
time-stable points can express measured water content both in TSP and field
water dynamics in topsoil and even in subsoil. This provides a basis for sample
strategy and verifications of hydraulic process.
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Rainfall (mm)
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