Different Vegetattion Types Community Structure And Soil Propertiesin Loess Hilly And Gully Region Ofnorthern Shanxi

This study is a comprehensive research and analysis in community structure and soil moisture,nutrients,enzymes of locust communities in different site conditions,as well as sea buckthorn,Caragana,Lespedeza bicolor,reeds,Agropyron,Artemisia and adsurgens community in Ansai County in the Hilly Area.The main conclusions are as follows:(1) There are different vegetation communities in the area,and mainly dicotyledonous plants.In locust tree,Rosaceae and Compositae are of which the major plants. Dicotyledon mainly in Rosaceae, Compositae and Leguminosae, and monocots, mainly concentrated in the grass. Therefore, Rosaceae, Compositae, Leguminosae and Gramineae flora in the area plays an important role. Locust community which mainly composed of the rose family, and Compositae, seabuckthorn communities, Caragana community, Lespedeza bicolor community, Artemisia community, wheatgrass community adsurgens community, mainly by Phragmites australis and beans Asteraceae Branch plants.(2) In the community of Robinia, the Pielou's index, Diversity index, Ecological dominance index of different slopes community difference achieved significant level(p<0.05); In three bush communities, Pielou's index, Margalef's index of Hippophae rhamnoides community and Lespedeza davurica community get significant differences(p<0.05), Ecological dominance index of Lespedeza davurica community is the highest, ecological dominance index of Hippophae rhamnoides community is middle , ecological dominance index of Caragana community is lowest ; In four grass communities, Margalef's index and Pielou's index of Phragmites australis, Astragalus adsurgens Pall. community and Artemisia capillaries community showed significant differences(p<0.05), Pielou's index of Phragmites australis community and Agropyron cristatum community showed significant differences(p<0.05), ecological dominance index of Artemisia capillaries community is highest , ecological dominance index of Agropyron cristatum community is more than that of Astragalus adsurgens Pall. community ,and ecological dominance index of Phragmites australis community is lowest .(3) The spatial variability of soil water content in different plant communities as follows: different site conditions in the Robinia community, in the soil depth is greater than 100cm, the soil moisture in shady slope communitiesis higher than that in sunny community; when the soil depth is greater than 120cm , soil water content with the growth and increasing forest age. Three shrub communities in the soil depth of 0-260cm, the big variations in soil moisture, and the soil water content of Hippophae rhamnoides community are lower than other communities; at a depth of 0-140cm soil , soil water content of Caragana community is higher, but deep in the soil, soil water content of Lespedeza davurica community is higher . Soil moisture content of several herbaceous plant communities as follows: Phragmites australis community relatively high soil moisture content, and Artemisia capillaries community is relatively low soil moisture, but in the 150cm soil depth below the soil moisture content Astragalus adsurgens Pall.community are lower than other communities.(4) Based on the Loess Plateau on soil nutrient content of different community classification standard soil organic matter, total nitrogen, available nitrogen, potassium, phosphorus statistical analysis showed that , these types of nutrients in the whole area at a low level. Communities in which only locust 0-10cm soil depth, the organic matter, total nitrogen, available potassium levels are high, while other nutrients (available N, P) content and shrubs, herbaceous community of soil nutrients (soil organic matter, total nitrogen, available nitrogen, potassium, phosphorus) have a low level, and some even reached very low levels. And in the soil below a depth of 20cm, all the communities available K, available P content difference did not reach significant level (p> 0.05). Different types of vegetation communities on nutrient accumulation effect has the table. And overall nutrient content as follows: that of tree is more than that of shrub,and that of herb is lowest, the soil nutrient of Lespedeza bicolor community is lowest.(5) The different vegetation types community on the soil enzyme have table effect, and the enzyme activity trees is more active than that of shrubs, herb. In the community in Robinia, show that slopes, plantation age are affected soil urease, catalase activity of factors, Slopes are the factors of affect sucrase activity, forest age is influence factors of amylase activity.(6) The different vegetation types of soil pH change in a small range, and partial basic. Different slopes pH value has significant difference(p<0.05).(7) Based on the relationship between soil factor analysis, in the different vegetation community,soil pH value and enzyme activity are different degree of negatively correlated(p<0.05); Soil organic matter and enzyme activity positively correlated (p<0.05),with alkaline phosphatase which reached significant correlation(p<0.01); Total N and alkaline phosphatase activities also has significant positive correlation(p<0.01), available nitrogen, total nitrogen and urease correlation reached significant level(p<0.05). (8) In the community of Robinia, soil water,soil nutrients,soil enzymes activity and the Pielou's index, Diversity index, Ecological dominance index as the growth of robinia plantation age and increased. In the community of bush, the Margalef's index ,Diversity index and soil nutrients,soil enzymes activity showed consistent change rule. In the community of herbaceous, soil water, nutrient content,soil enzymes activity and the Margalef's index ,Diversity index, Pielou's index showed consistent change rule.