A study on plantation soil desiccation in the upper reaches of the Fenhe River basin based on deep soil experiments
汾河流域上游人工林地深层土壤干燥化探讨

This article is a research report of soil desiccation based on our research of the soil in which the artificial poplar woods and the apricot woods have been growing for over 30 years in Jingle,Loufan,and Lanxian counties of Shanxi Province,which are the key sites of environmental ecological administration in the upper reaches of the Fenhe River.820 soil samples were separately taken from the depth of 0-600cm at 14 sampling points.The soil moisture data sequence in these sampling points was obtained.The different ages of the woods and the different water consumption of different vegetations in different places and vegetal periods were analyzed.The research results are: that in the soil 2-4m underneath the 10-year-old poplar woods was 9.89% in Loufan County,and in the soil 2-4m under the 20-year-old poplar forest was 7.88% in Loufan County,the average water content in the soil 2-4m beneath the 18-year-old poplars was between 7.27% and 8.83% in Lanxian County;the average water content in the soil 2-5.7m under the 30-year-old poplars growing on the sunny slopes was 9.02% and on the shaded slope 2-4m underneath the forest was 9.72% in Jingle County.All these indicated that the profiles of the soil reveal the features of light or medium development of dry layers.It is concluded that development of dry layers is universal in the soil under the artificial woods of the upper reaches of the Fenhe River.Terrain,climate and vegetation have exerted great impacts on the development of dry layers.Generally,soil desiccation in artificial forestlands on the ridges and loess hills are more intense than those on the low-lying and gulch locations.And soil desiccation on sunny slopes are more intense than those on shaded slopes.Scarce natural precipitation is an important factor accounting for the formation of the dry layers.It is proposed,from the perspective of vegetation suitability,that the law of vegetation development should be followed,grain-for-green programs be scientifically performed,ecological special zones be established,scientific eco-environmental programming in the upper reaches of the Fenhe River be conducted,and measures such as planting drought-enduring and low water-consuming sparse woods be taken in areas where light dry layer developed and served as source area to conserve water supply and provide drinking water for Taiyuan City.This research is expected to offer the theoretical basis for ecological recovery of this area.