SCHRIFTENREIHE Institut für Pflanzenernährung und Bodenkunde ...

Recommendations

Info

epellency and the organic matter content. However, Greiffenhagen et al. (2006) showed a good correlation between soil organic matter, bulk density and water characteristics which could be easily used to predict plant available water. Lavee et al. (1996) fo<strong>und</strong> a correlation between aggregate stability and soil organic matter content and presumed that grazing and human activities interfere with the development of aggregate stability. Fullen et al. (1996) argued that soil organic matter tended to be associated with silt and clay contents rather than with sand content for Hilton soils. However, aggregate stability also might relate with soil texture. A good relation among soil strength, texture and stress dependent changes of the pore size distribution were reported by Horn and Fleige (2003). 14 The current research focuses on the seasonal changes and spatial dependence of soil properties. Although many investigations have been dealt with the productivity and stability of grassland ecosystems, conclusions aiming at the development of sustainable management strategies are hard to be derived from those studies. It is reasoned that firstly the complex and dynamic interaction of soil properties influencing plant growth often remains unidentified, and secondly spatial autocorrelation/variation of soil related parameters is usually ignored. The paper serves to close this gap by performing a combined analysis of soil hydraulic and mechanical processes as well as their spatial variation. Therefore, our objectives are (i) to estimate the effect of grazing intensity on soil mechanical and hydraulic properties on the plot scale; (ii) to investigate the spatial variability of soil properties in the surface soil; and (iii) to explore the correlation between soil properties. 2. Materials and methods 2.1. Experimental site and layout The experimental area is located within the Xilin River Basin (43º38´N; 116º42´E), Eastern Inner Mongolia and administered by the Inner Mongolia Grassland Ecosystem Research Station (IMGERS), <strong>Institut</strong>e of Botany, Chinese Academy of Sciences. Vegetation is characterized as a Leymus chinensis steppe, which is typical semi-arid grassland in the Eurasian mid-latitude zone. The growing season usually starts in May and ends in late September. Under
Chapter 2 Spatial variability of soil properties affected by grazing intensity in Inner Mongolia grassland temperate semi-arid continental climate, the annual mean air temperature was 0.7 °C and the annual total precipitation was 343 mm, of which 60-80% was received from June to August. The experimental site is on a smooth rolling landscape, approximately 1270 m in altitude with a mean relative height of 20-30 m and slope of an inclination 100 cm, followed by an Ach-layer. Fig. 2.1. Location of geostatistical areas in the five plots. UG 79: ungrazed since 1979, UG 99: ungrazed since 1999, WG: winter grazed, CG: continuous grazed, and HG: heavily grazed. Each plot has an area of 105 m×135 m. Sampling points are spaced every 15 m with a subgrid spacing of 5 m (the orthogonal boxes with dash line in WG and CG). Two larger geostatistical grids in WG and CG have an area of 300 m×550 m with a sampling points spacing of 50 m and a subgrid spacing of 10 m. Before 1979, the whole area is lightly grazed by herds that are composed of 70-90% sheep and 10-30% goats. Our measurements were conducted in five field plots of different grazing intensities: two ungrazed plots, fenced since 1979 and 1999 respectively (hereinafter referred to as UG 79, 24 ha and UG 99, 35 ha); and three grazed plots, one grazed only during winter with 0.5 sheep units 15
Page 1 and 2: SCHRIFTENREIHE Institut für Pflanz
Page 3 and 4: Aus dem Institut für Pflanzenernä
Page 5: I Table of contents I Table of cont
Page 8 and 9: controlling soil moisture are of pa
Page 11 and 12: Zusammenfassung Überweidung wird a
Page 13 and 14: Die Beweidung beieinflusst besonder
Page 15 and 16: II List of figures Fig. 2.1. Locati
Page 17 and 18: measured soil moisture in time stab
Page 19 and 20: III List of tables Table 2.1. Descr
Page 21 and 22: 1.1 Background Chapter 1 Introducti
Page 23 and 24: Chapter 1 Introduction is also unce
Page 25 and 26: Chapter 1 Introduction water in spr
Page 27 and 28: Chapter 1 Introduction requires the
Page 29 and 30: Chapter 1 Introduction Krümmelbein
Page 31 and 32: Chapter 2 Spatial variability of so
Page 33: Chapter 2 Spatial variability of so
Page 59 and 60: Chapter 3 Spatio-temporal variabili
Page 73 and 74: Chapter 3 Factors controlling spati
Page 85 and 86:
Chapter 4 Temporal stability of soi
Page 87 and 88:
Page 89 and 90:
Y orientation Chapter 4 Temporal st
Page 91 and 92:
Page 93 and 94:
MRD(%) MRD(%) 100 80 60 40 20 0 -20
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Soil water content (%) 40 30 20 10
Page 103 and 104:
Page 105 and 106:
Chapter 5 Modeling Grazing Effects
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Chapter 6 Modeling of Coupled Water
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Chapter 7 General discussion and co
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
References Chapter 7 General discus
Page 169 and 170:
Page 171 and 172:
8. ACKNOWLEDGMENTS Firstly I would
Page 173 and 174:
Curriculum Vitae M.Sc. Ying Zhao Of
Page 175:
Schriftenreihe des Instituts Neuere
show all

SCHRIFTENREIHE Institut für Pflanzenernährung und Bodenkunde ...

Create successful ePaper yourself

Delete template?

Save as template?