SCHRIFTENREIHE Institut für Pflanzenernährung und Bodenkunde ...

Chapter 7 General discussion and conclusions
7. General discussion and conclusions
In Inner Mongolia grassland, grazing-induced changes in the productivity and
stability of grassland ecosystems have been reported recently. However, the
environmental impact of grazing and especially the role of different grazing
intensities are not well be understood. This study therefore concentrates on the
effect of grazing on soils, plant ecosystem and surface fluxes at multiple scales
in general, and on modeling grazing effects on coupled water and heat fluxes at
the plot scale in particular.
Spatio-temporal variability of water-related variables affected by grazing
intensity (Chapters 2, 3 and 4)
The characterization of the spatial variability of water-related variables is
essential to achieve a better understanding of eco-hydrological processes
accompanied by environmental changes. In agreement with other studies (e.g.
Shouse et al., 1995; Lophaven et al., 2006), we also found that soil properties
exhibited a moderate to strong spatial dependence. Furthermore, this spatial
dependence was modified by grazing management, e.g. heavy grazing resulted
in a more homogenous spatial distribution of soil properties. We partly attributed
it to soil compaction effects accompanied by animal trampling. Multiple
regression analysis showed significant correlations among various soil variables,
this is in agreement with our assumption that regionalized variables are
correlated each other. Especially, multivariate geostatistical analysis further
revealed a scale-dependent correlation between controlling parameters affected
by grazing intensity. To our knowledge, there are few studies describing the
interactions of spatial variability of soil properties affected by land management
at multiple spatial scales (Williams et al., 2003). Recently, Casa and Castrignanò
(2007) applied factorial kriging analysis to clarify the spatial relationships
between the different variables acting at the different scales. Our studies are in
agreement with it, we considered this approach will be helpful to explain the
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