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ungrazed plots (Table 3). WG differed from the other grazing intensities as SWC evolved in the micro- (random;
Chapter 3 Factors controlling spatio-temporal variability of soil moisture using multivariate geostatistics heterogeneity of soil moisture. As grazing intensity increased, animal trampling and grazing decreased vegetation coverage and biomass, leading to increased bulk density and decreased soil organic carbon. With heavy grazing this results in a large proportion of bare soil and highly deteriorated soil properties. Under such conditions, high evaporation and albedo are expected, leading to a trend towards lower soil moisture and a more homogeneous moisture distribution at the long-range scale. To completely understand the controlling factors of soil moisture from these data, several more considerations are needed. For example, correlations derived from a single measurement, i.e. plant properties, normally omit seasonal variations. Another deficiency is the lack information of soil moisture for deeper soil, and potential shifts in sampling position and frequency. Although trends between grazing intensity and soil moisture distribution were found, uncertainties in the grazing gradient and its management history may have confounded the results. Nevertheless, a conceptual model of the mechanistic controls on surface soil moisture variability affected by grazing intensity could be derived. 4. Conclusions In this paper we identified the main factors controlling the spatio-temporal patterns of soil moisture as a function of grazing intensity in a semi-arid grassland. Our results revealed that the variability of soil moisture was characterized by weak to moderate spatial structures depending on sampling time and grazing intensity. The spatial variance and, to a lesser extent, the correlation length were found to be related to mean soil water content. The correlation analysis showed that soil and plant properties, especially soil physical properties that were impacted by grazing intensity, were important in controlling the distribution of soil moisture. To adequately describe spatial patterns of soil moisture, we need to consider the dependency of controlling processes on the local conditions. Using factorial kriging analysis, scale-dependency correlations between soil moisture and its controlling factors were detected. The soil and plant properties strongly controlled the variation of soil moisture in UG 99 at short-scale (90 m), 59
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SCHRIFTENREIHE Institut für Pflanz
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Aus dem Institut für Pflanzenernä
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I Table of contents I Table of cont
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controlling soil moisture are of pa
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Zusammenfassung Überweidung wird a
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Die Beweidung beieinflusst besonder
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II List of figures Fig. 2.1. Locati
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measured soil moisture in time stab
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III List of tables Table 2.1. Descr
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1.1 Background Chapter 1 Introducti
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Chapter 1 Introduction is also unce
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Chapter 1 Introduction water in spr
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Page 29 and 30: Chapter 1 Introduction Krümmelbein
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Page 85 and 86: Chapter 4 Temporal stability of soi
Page 89 and 90: Y orientation Chapter 4 Temporal st
Page 93 and 94: MRD(%) MRD(%) 100 80 60 40 20 0 -20
Page 101 and 102: Soil water content (%) 40 30 20 10
Page 105 and 106: Chapter 5 Modeling Grazing Effects
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Chapter 5 Modeling Grazing Effects
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Chapter 6 Modeling of Coupled Water
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Chapter 7 General discussion and co
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References Chapter 7 General discus
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8. ACKNOWLEDGMENTS Firstly I would
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Curriculum Vitae M.Sc. Ying Zhao Of
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Schriftenreihe des Instituts Neuere
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