Study On The Vegetation And Soil Characteristics Of Pearshrub (Caragana)-Grassland In Restoration Process In Arid Sandland Of Eastern Ningxia

The dynamic changes of vegetation and soil characteristics were analyzed in restoring pearshrub (Caragana)-grassland planted in different years and different density in Eastern Ningxia, compared with the natural restoring grassland. The results are as followings:1.There are 32 families, 77 genera, 83 species spermatophyte to be collected in test section, the sequence number of plant species in pearshrub (Caragana)-grassland at different plant-age is: 6a pearshrub (Caragana)-grassland>11a pearshrub (Carflrgana)-grassland>17a pearshrub (Caragana)-grassland> Artemisia ordosica-grassland, and the perennial plant Legume and Gramineae are the dominant species in pearshrub (Caragana)-grassland, whereas annual plant and Artemisia ordosica are dominant in naturally restoring Artemisia ordosica-grassland.2. Species diversity of plant community changes obviously. Tendency of the diversity index change is: 6a pearshrub(Cara,gama)-grassland>11a pearshrub (Caragana)-grass\and > 17a pearshrub (Caragana)-grassland > Artemisia ordosica-grassland, same as the homogeneity index change, contrary to the ecological dominance change.3.In 0~40cm soil layer in which much plant radicel distributes, water content change tendency is: 6a pearshrub (Caraga/za)-grassland>17a pearshrub (Caragana)-grassland > Artemisia ordos/ca-grassland > lla pearshrub (Caragana)-grassland; in 0~20cm, soil nutrient content changes inconsistently, the soil available P is: 6a > 17a > Artemisia ordosica-grassland>11a; soil available K is: 17'a>6a>11a>Artemisia ordos/ca-grassland; soil hydrolyzed N is: Artemisia ordosica-grassland>lla>6a>17a; soil organic is: Artemisia ordosica-grassland > 11 a> 6a> 17a.4.1n pearshrub (Gzragana)-grassland of different density, the number of plant species tendency is: 4m>10m>6m, plant Community coverage is: 6m>10m>4m. Perennial Gramineae Penisetum centrasiaticum is the dominant species in bandwidth of 6m pearshrub (Caraga/jflr)-grassland, whereas the Gramineae is exiguous in 4m and 10m pearshrub (Caragana)-ffassland, Artemisia ordosica is the dominant species in 4m pearshrub (CarflgtfHtf,)-grassland, Astragali's melilotoides Pall is dominant in 10m.5.1n different bandwidth density of pearshrub (Catratgana(-grassland, change tendency of species diversity of plant community is: 4m>10m>6m, similar to homogeneity index change, and contrary to the ecological dominance change.6.1n 0~20cm soil layer of different bandwidth pearshrub (Caragflnaa)-grassland, in 0~ 100cm, soil nutrient (hydrolytic-N, available-P, available-K, Organic) content change tendency is: 4m> 10m>6m, and the soil water content change is: 4m> 10m>6m.