**2. Material and methods**

#### **2.1 Study site and plot layout**

The study area was based in the Ningxia Hui Autonomous Region of Eastern China (37°04<sup>0</sup> � 38°10'N, 106°30<sup>0</sup> � 107°41<sup>0</sup> E) and features an elevation of 1,295 � 1,951 m. Yanchi County is connected to the Mu Us Sandland in the north and to the Loess Plateau in the south, which is considered to be a typical geographic transition zone. Desertification areas are expanding in Yanchi County due to overuse of ecosystem resources. Sand land has become one of the main landform types in the Ordos slope hills of the area. The total area of Yanchi County is 8,661.3 km<sup>2</sup> . It has a typical temperate continental climate with hot summer, cold winter, extensive drought, significant wind, and strong evaporation. The average annual temperature was 8.1°C.The average annual rainfall was 250–350 mm, wherein greater than 80% of the rainfall occurred from May to September. The primary winds in the area were west and northwest winds. The main soil of Yanchi County is sierozem, followed by black loam and eolian soil [16]. The primary vegetation in Yanchi County is classified as a transition zone between the central Asian sub-regions of Eurasian steppe zone and the central steppe region. Vegetation types in the area include shrubs, steppe, meadows, swamps, and deserts. Vegetation exhibits transitional characteristics with gradual succession that is staggered extending from the south to the north. Yanchi County contains only plantation forests that mainly consist of *Salix psammophila* shrubland and *C. microphylla* shrubland [17]. The survey included semi-fixed dunes without *C. microphylla* plantation (plot ID: NO.1), and soil substrates were sierozem [18]. The dominant species in Plot 1 are *Agriophyllum squarrosum* and *Setaria viridis*. *C. microphylla* plantation with 7, 16, 25, and 37 years were included in the study and are identified as plots NO.2–5, respectively. Lastly, a neighboring natural steppe that did not exhibit

*Evaluation of Soil Seed Banks in Different Aged* Caragana microphylla*… DOI: http://dx.doi.org/10.5772/intechopen.98712*

desertification was used as a control (NO.6) (**Figure 1**). The dominant species in Plot 6 are *Artemisia scoparia* and *Sophora alopecuroides.*
