Abstract:Based on the oretical analysis,field examination and investigation,it is considered that the 2.0t/ (hm² . a) is the rational soil loss tolerance of sloping field in semi-arid hill-gully area of the Loess Plateau during the long period according to soil formation velocity,top soil nutrient balance,land productivity stability in sloping field,sediment transport tolerance of the Huanghe River course,and regional economic development and so on.

Abstract:In the all processing of pipe constructing and laying, vegetation-eliminated and earth surface avulsed and soil piled incompact resulted in soil erosion more seriously. According to the character of pipeline constructing and laying and the local environment of the loess hilly and gully area in Shaanxi Province, the Liuping to Yaodian oil transportation pipe is taken as an example to forecast the amount of soil loss which includes discarding soil and dregs, destroying original landforms. To induce and avoid the loss, some integret-ed measures, such as ecological engineering and other kinds of measures, are put forward accordingly.

Abstract:Based on 3-year continuous field observations and laboratory analyses,the aboveground and the belowground nutrient cyclings were studied in mountainous grassland ecosystem of Jian'ou City. Each kind of nutrient content in the soil followed the order of AlFeKMgCaZnNMnP,it indicated the chemical characteristic of acid soil in the subtropics. The active elements, such as N,P,K and Ca,played an important role in the flows of material and energy because their cycle coefficients were greater than other elements like Al and Fe.In order to develope the mountainous grassland ecosystem,it was the key way to increase contents and availability of N,P,K and Ca in the soil and nutrient fluxes between vegetation and soil.Further, from the point of the soil and water conservation,suitable native grass species can be planted for increasing biomass and surface coverage in grassland ecosystem.

Abstract:Three plants of Pinus massoniana, Elaeagnus pungens and Vetiveria zizanioides, which fitted for growing as the pioneer plants of the ecological restoration,are selected by the different experiments according to the physical and chemical character of mining wasted lands of Kaolinite minerals.According to the experimental results,it was thought that the logical community structure of herbages with shrubs and trees,specially nitrogen-fixing plant of the leguminous plant with the management of the backfilling mature soil,is an effective way for quickly restoring the soil fertility and vegetation growth,and the ecological environmental restoration which had been aggrieved.

Abstract:On the basis of the characteristics of grassland resources and current conditions of grasslands of Northern Tibet Plateau, the limit factores to vegetation restoration are identified, which include grassland degradation caused by both natural and artificial factors. The main ways to implement correct measures in vegetation restoration should include the ways of making rational use of natural resources, soil cultivation, founding forage production bases in other districts and strengthening research work.

Abstract:Sichuan-Tibet Highway is located in the southwest of Qinghai-Tibet Plateau.Water damage to roadbed near rivers along the highway is very serious because of the complicated characteristics of geology,geomorphology, climate and hydrology. Based on field investigations,the causes and types of water damage were discussed,and the prevention of it were put forward. Finally,the application of prevention methods of water damage was applied in the K4238+196-K4239+150 section of Sichuan-Tibet Highway.

Abstract:On the basis of developed soil erosion model on the middle and east part of Guanzhong plain, the soil erosion intensity and their units are estimated in Heihe basin. The relative error between the exist results and field survey of hydrographic stations were in the allowed duration. The spacial distribution of soil erosion intensity were shown and the relationships between soil erosion intensity and land use types were discovered in the Heihe basin. Adjusting land use structure and reconstructing vegetation ecosystem would be basic way for reducing soil erosion and prolonging the lifetime of Heihe reservoir.

Abstract:Based on the distribution function of raindrop diameters delivered by Best A.C.,a new theoretical distribution density function for raindrop kinetic energy was developed, which obeyed the Weibull distribution.The study showed that the Weibull distribution could be excellently used in describing rain kinetic energy distribution.Thus, it is not necessary that the total rain kinetic energy was calculated by various empirical formulas,rather,it should be obtained through calculus straightforwardly.

Abstract:The classification accuracy is unsatisfactory in the complicated terrain area of the Loess Plateau when the single supervised classification is used in the remote sensing investigation of slope field. Taking the loess hill and gully area of northern Shaanxi Province as a test area, the slope field and other categories are extracted by the improved classification which is the integration of supervised classification and unsupervised classification. The result shows that this method improves classification accuracy greatly, and is suitable for the slope field investigation in the loess hill and gully area. The research is of critical significance in obtaining the up-to-date information of the slope field and converting farmland into forest or grass land in slope land reasonably.

Abstract:The soil and water loss on linear zone development and construction control project had the characteristics of period and complexity. The monitor of linear zone development and construction project was more difficult compared with the monitoring work of small watershed and other construction project. Based on its soil and water loss and treatment characteristic, the monitoring technology of linear zone development and construction project was elaborated from its content, object, item and method. It can be applied on references for designing the soil and water conservation monitoring schemes of other similar projects.

Abstract:The comprehensive control of soil erosion in small watershed is the soil conservation technique with Chinese features. The establishment of digital information system of small watershed management with 3S techniques should be based on the remote sensing and others, including the determination of catchment areas(10-20 km²) with the mountain ridges as boundary; drawing the small basin boundaries according to geographic information software and importing 18 figure small watershed code into computer. Because of the necessity of management, several small basin maps should be drawn according to the management patterns for the cities, counties or villages; for the basins or for the upper reaches of reservoir. Thus, the important basis is suggested to serve all grades of administration department to improve the management level of water and soil conservation.

Abstract:The continuous investigation and experiment on different vegetation in the loess hilly and gully region in past 10 years were conducted. The results indicate that soil moisture content varieties among the artificial grass, the seabuckthorn and the Chinese pine woodland are basic consistence in the long series years, the water resources were 100-140 mm in 1 m soil layer, and the soil was in "dry horizon" stage during growth period. Soil water content in natural grass land was about 40mm higher than artificial grass land in a year, the soil humidity was always in proper and stable level. The woodlands, seabnckthorn and Chinese pine, express the growth condition that are adapte to the weather character. But from the point of hydrological circulation condition, the long time "dry horizon" stage of soil humidity was disadvantage for vegetation growth and ecosystem development. The runoff experiments indicate that the average runoff of artificial grass land and Chinese pine woodland was 1. 45 mm and 1. 27 mm, the runoff coefficient was 0.08 and 0.07; The natural pasture and the seabuckthorn woodland did not produce big runoff during a year. The runoff was also small, and lots of them were clear fluid. Therefore, the managing measures of vegetation instauration should appropriate to its natural restoration and protection, and make greatly use of the runoff resources to add soil humidity, and to develope toward the benefical vegetation growth direction.

Abstract:The amount of water consumption of natural plant is a part of its amount of water requirement, and also the basis to determine its amount of water requirement. Ejina County lying in the lower reaches of Heihe River basins, belongs to an exceedingly arid region, and only on the bank of Heihe River, there are banded oases nourished by groundwater supplied by the river water in the upper and middle reaches, the left region all is covered by desert. In Ejina County, the main landscape is natural oasis. Alhagi sparsifalia is a familiar kind of perennial natural undershrub in the natural oasis, it has the common character of natural plants in Ejina County, its underground biomass is more than its overground biomass and its lateral roots is very abundant. So to make clear the rule of water consumption and to determine the ecological amount of water consumption of Alhagi sparsifalia will provide scientific basis for determining that of other natural plants in Ejina County. At the same time, this will provide a scientific basis for maintaining present ecological environment of Ejina County. The ecological amount of water consumption of Alhagi sparsifalia is successfully calculated by potential evapotranspiration multiplying a reduction factor, and the reduction factor is determined by soil moisture volume percentage and roots efficacious length. It is obtained that the annual amount of water consumption in natural Alhagi sparsifalia woods in Ejina County is 132.002 mm, mainly coming from the phreatic water evaporation and the soil moisture storage.

Abstract:Based on the locust woodland and scrub-herbosa land . the role of the main economic forest types of diospyros kaki woodland and castanea mollissima woodland on interception and distribution of precipitation was been studied in Huangqian reservoir area. The results show that, in general, the water resource conservation function between these four woodlands seems to be locust woodland diospyros kaki woodland castanea mollissima woodland scrub-herbosa land, which means the function of water conservation and soil erosion control of economic forest is between forest and scrub-herbosa.

Abstract:There is a dispute about existence of a long period from Eastern Han Dynasty to Tang Dynasty (90-870 A D) in history,when flood was rarely on the lower reaches of Yellow River.It was considered that the long period without severe flooding on the lower reaches of Yellow River during 70 -870 A D is assuredness based on the historical recordation and by using the disaster system analysis.The cause of rare flooding on the lower reaches of Yellow River was resulted from the integrated effect of multi-factors.The main causes include three factors as following.(1) The water quantity reduction of lower reaches of Yellow River results in the cold - dry climatic period,and the decrease of the loss of water and soil owing to the change of land use mode in the Loess Plateau which lead lessen of sandy quantity in the lower reaches of Yellow River.(2) Greatly improve the prevent flood ability because of the control engineerings of Yellow River and there are lots of lake and swampy in the lower reaches of Yellow River.(3) The sparse population of North China Plain was resulted from war, and conduce the lower on the social frangibility.

Abstract:Soil erosion is one of the most serious eco-environment problems, which limits the development of society and economy along the Yellow River of western Shanxi Province. In this region, water erosion land covers 20777km² and it is accounting about 79. 30% of the total land area in the 1990s, while water erosion land covers 17912.54km² and it is about 68. 37% of the total land area in the 1970s. In other words, the increasing rate of soil erosion was 143.23km² per year in recent 20 years. Soil erosion resulted in some negative impact on the society and economy in study region, such as cultivated land area reduction, land productive potentialities declining, water conservancy facilities destroying, ecological environment degradation and so on. Finally, some strategies of ecological construction for preventing water and soil loss are put forward according to the physical condition of this region.

Abstract:Based on the request and the connotation of ecological demonstration area's sustainable development, the theory of compound ecological system is used to analyze the structure of county scale ecological demonstration area, and its hierarchy and function are demonstrated. The degree of sustainable development (DSD) index is formed, and its constitute is expatiated upon. According to DSD, taking Mizhi County in Shaanxi Province as an example, the variety and regional sustainability are analyzed.

Abstract:The wetland reserve of Danjingkou reservoir is the typical representation of wetlands transiting from subtropical zone to warm temperate in China. There are abundant resources of zonic and botanic in the studied area. According to existing problems, the protecting and managing measures were suggested as follows: (1) to set up a national wetland reserve; (2) to make use of forestry ecological projects and other projects for soil and water conservation; (3) to develop resource management information system of the reserve. These measures are of significance in ensuring bio-diversity, water quality of the water diversion project at the middle line and economic sustainable development.

Abstract:The soil erosion of the upper and middle reaches of Yangtze basin is very serious, and threatened the sustainable development of the whole basin society, ecology and economy. Though the three big engineering measures, which are the comprehensive control engineering of the Yangtze Rive basin like the protection engineering of natural forest, and the transformation engineering from farmland into forest or grass land, have controled soil erosion to some extent, it still has many limitations and shortcomings. Because it is very important to restore soil erosion of the Yangtze basin, these limitations are analyzed carefully, and a series of new model for the ecological restoration of soil erosion of the Yangtze River basin are put forward, such as taxing ecological, developing eco-economical agriculture, implementing ecological emigrant, enlarging ecological import and developing ecological tourism.

Abstract:Sustainable development theory is still in the initial stage being used in the field of soil and water conservation. The indexes of small watershed management for sustainable development are established, according to the society-eco-nomy-environment integrated system development, and the benefits of small watershed comprehensive management. The evaluation indexes are divided into six grades.