The Holocene Paleosol And Soil Moisture Environment In Guanzhong Plain

Vegetation planting is the main measurement of ecology construction in Loess Plateau and trees are planting in the south to Yan'an area. If the area is not fit for planting trees, the forest would not grow well, which would cause great financial loss; what's more it would cause the vegetation degrading and the soil drying. The Holocene is the last stage of human history, which has great effect on climate at present. The study on the vegetation of Holocene in the middle and south of Loess can instruct the vegetation construction nowadays.As underground water buried deeply in Loess Plateau, the soil water from precipitation influx is the main source to the vegetation. The volume of soil water decides the kind of vegetation in the area. Many researches had been done on soil water in Loess Plateau. It was known that the badly-grown artificial forest was caused by the great dried soil layer. The research shows that the influx depth of gravity water in soil can indicate the existence of dried soil layer and the degree it developed, which is the key factor to decide the kind of vegetation. In Loess Plateau, the influx depth of gravity seldom reaches 2m underground and the pellicular water lies below 2m, which moves with a low speed and little contain. It is apt to form the long-term dried soil layer and badly lack of water.Based on outdoor observation and indoor experimentation, the thesis takes the Holocene as the research period. Many index such as Calcium carbonate, grain size; geochemical elements and soil micro morphology are selected to indicate the Loess and paleosol in Holocene in Guanzhong Plain. The soil and soil moisture environment are researched in Holocene in Guanzhong Plain. The conclusions are following:(1)Combine the CaCO₃ illuvial-depth model, the moving rule and distribution of soil moisture in the earth layer, we research the precipitation in Holocene and check it with the precipitation in modern. It was known that the gravity water influx to the 3m underground in Wangzhuang Profile in front of Qinling mountain and 2.12m in Ancun Profile and Xiyangwancun Profile in the middle of Guanzhong Plain and 2.3m in Yongchuanzhen Profile in the west of the Guanzhong Plain. The precipitation was about 800mm in Holocene. The gravity water height and the capillary moisture height, which...