SCHRIFTENREIHE Institut für Pflanzenernährung und Bodenkunde ...

Chapter 1 Introduction
requires therefore appropriate sampling strategies and monitoring (or modeling)
sites. The temporal stability concept might aid to estimate field mean water
content whether hydrological model is applied in a time stability point. However,
until now this has not been fully used and tested to estimate the water content
and flux for a given probability level by a hydrological model. The purposes of
this study are: i) to investigate the temporal stability of soil moisture under
different water conditions, ii) to explore the grazing impact on temporal stability
of soil moisture, and iii) to infer how far the time stability concept can be applied
for the hydrological model to make reliable estimates of soil moisture.
Chapter 5: “Modeling grazing effects on coupled water and heat fluxes in
Inner Mongolia grassland”
What are the grazing influences on soil bulk density, crusting, aggregation and
hydrophobic features? How do parameters like soil texture, water retention
properties and infiltration capacity change the modeling results of soil water
movement? In this paper, in situ measurements of soil, plant and weather data
were used to parameterize the model HYDRUS-1D, by which water and heat
fluxes were simulated as a function of grazing intensity. The modeling results
were verified by comparison with the measured data of soil water and
temperature. The objectives of this study are (i) to quantify water and heat
budgets affected by grazing intensity via calibrating HYDRUS-1D, and (ii) to
define water use mechanisms in Inner Mongolia grassland.
Chapter 6: “Modeling of Coupled Water and Heat Transfer in Freezing and
Thawing Soil”
In this study, we further address the field application of a new freezing code
incorporated into HYDRUS-1D, which numerically solves coupled equations
governing phase changes between water and ice, and heat transport with a
mass- and energy-conservative method. The seasonally frozen soils in Inner
Mongolia allow us to evaluate the effect of snowmelt and soil thawing water on
surface runoff and seasonal water cycle. Specifically, we will focus on discussing
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