Abstract:It has been well known that soil and water loss is the first eco-envi ronment problem which has been the crucial factor to limit sustainable development of society and economy in China. On the view of preventing and relieving the disasters, the present situation and the problems on soil and water loss were analyzed, and the achievements and experiences relevant to soil and water conservation were summarized. The countermeasures to further strengthen soil and water-based eco-environment construction in the new situation were put forward.

Abstract:The recent progress of polymers applied in soi l and w ater conservation is review ed. By means of creating and stabling aggreg ate structure, improving water infilt ration and decreasing soil erosion, the soil and water runoff was controlled by polymeric amendments. The beneficial results of polymeric amendments in soil and water conservation were influenced by a few factors, such as properties of polymer, methods of addition and salt effect of electroly te, etc.

Abstract:There have been abundant research results on sediment variation in the middle reaches of the Yellow river. The current research results have been summarized from three facts: changes of the sediment variationith time and space, some questions in the research on the sediment variation and trend prediction of the future sediment variation. Based on the existing results, some views for the research on the sediment variation there have been put forward.

Abstract:In the whole arrangement of our nation economy development, the loess plateau region acts as an important strategic position which connects the east and west of China. The sustainable development of the loess plateau can set an example to the development of the west China. Based on analysing the state of sustainable development of the loess plateau, the structure frame of sustainable dev elopment index system and sustainable development evaluation method are studied, the structure frame of sustainable dev elopment index system including three types of index such as advanced comprehensive index, basic index and element index has been desig ned, the AHP which can be used to calculate the sustainable development index weight supported by entropy technology,and compositeev aluation model that can evaluate the sustainable development of the loess plateau comprehensively. The scientific theory of regulating and inducing the sustainable development of loess plateau region is provided.

Abstract:The debris flow sediment is located at Laomao mountain gullies, in south Liaoning province, which forms in unique physical geog raphical environment of east coastland of China. The area belongs to temperate zone,monsoon climate is regulated by intense martin climate. Precipitation concent rates in summer by the type of torrential rain. This condition helps to debris flow process. In view of mechanism, the debris flow is unique rapid and temporary torrential rain-typed one. Sedimentary structures of the debris flow show bulky grain size migmatite. By analyzing the sediment grain sizes, the author leads into concept of likelihood of grain size distribution and pursues the debris flow grain size distribution patterns.

Abstract:A field rainfall simulation experiment was carried out to assess the impacts of conservation tillage on run off and infilt ration, and the effects of surface tillage, residue cover and wheel traffic compaction were also studied. The results showed that conservation tillage, which features more residue cover and less soil disturbance,could remarkably delay and reduce runoff and improve infiltrati n compared to conventional moldboard plough practice (CK) . Under the experimental situation with lowantecedent soil moisture and 72 mm/h of simulated rainfall rate, CK could produce runoff 12～16 minutes earlier, and the final infiltration rate could be 60. 9% lower and total runoff could be 11 times more than conservation tillage. Among the three factors, residue cover is more efficient for reducing runoff and increasing infiltration. Wheel traffic compaction also has considerable impact and could increase runof f by 4. 5 times; while the effect of surface tillage is not great. Conservation tillage combined with less traffic compaction can be an effective option to control run off from loess farmland.

Abstract:Soil anti-scourability on slope cropland during different growing stages was monitored. The factors effecting the soil anti-scourability and its feature under different corps and growing periods were discussed. It may provide some scientific base for conservation tillage and benefit evaluation of soil conservation practice.

Abstract:Soil and water conservation benefit is a key target to measure the efficiency of soil erosion control. The accuracy of soil and water conservation benefit is dependent upon accurate calculation, accurate benefit parameters and accurate analysis of active principle. This provides a relatively practical method to calculate soil and water conservation benefit.

Abstract:Because of its large waste quantities and large damage areas of plant and original geological surface, road const ruction programmes have caused a series of ecological problems along the road line. As for to solve the main problems existed in the comprehensive harness plan composition for soil and water conservation on road construction programmes, the problems from the aspectes of soil and water conservation law and technique are analysed and discussed, then the related solutions are given.

Abstract:In recent years, the soil deterioration whose characteristic is the land degeneration of the artificial forestry and grass lands is being worse and worse. And soil desiccation whose characteristic is critical deficit of soil moisture continuously is taken seriously. Soil desiccation can form dried soil layer, result in soil deterioration, slow down the velocity of vegetation growth, cause community declination and death, and imperil seriously ecological environmental construction in the no rth area of China, especially in the loess plateau. So, studying and solving dried soil layer have become the urgent task for the v egetation constructio n in the loess plateau. According to the soil moisture data of Yanan experimental area, dried soil layer of vegetation is analy zed preliminarily, the statuses of dried soil layers between the different forestry and grass plantation are compared, and the meaning of solving dried soil layer is put forward.

Abstract:Based on thoroughly analyzing the current situation and existent problems during the exploitation of water resources in view of the sustainable development, it is pointed out that the contradiction between supply anddemand of water resources is continually aggravating and water crisis stands out gradually, therefore it is imperative under the situation to actualize the sustainable exploitation strategies of water resources. The model of sustainable utilization of water resources - the model of water resources wealth transferring between the generations is established and the countermeasures of sustainable utilization of water resources in China are put forward.

Abstract:The planting technique of micro-water harvesting includes two parts: water harvesting area and planting area. The water harvesting area is a ridge mulched with plastic film, even small rain can easily run down planting area, so soil moisture in planting area can be improved greatly. The technique has been developed in dryland of the south part of Ning xia province in order to improve the capability of soil water supplying in planting area, decrease the water stress and increase the WU E. The results of experiment from 1997 to 1998 show that the water consumption of millet increased by 92.2%～119.3%, the yield of millet increased by 63. 6% ～98. 1% compared with CK. And WUE reaches to 7.75～12.65 kg/(mm·hm_{2) . Effect of the ridge with 60cm width is prior to the ridge with 75cm wide on improving millet yield.}

Abstract:MATLAB, an advanced computer language used for scientific calculation, is introduced. It was used to analyze the data on soil moisture in bare land, felled fo restry land and Chinese pineland obtained by the long-term measure. The result showed that the soil moisture in the Chinese pineland was the least at the depth of 40-600cm among the three type of land, which indicated that Chines pine mainly consumed the water in that soil layer.Soil moisture in felled land w as more at the depth of 0-400 cm and less at the depth of 400-600 cm than that in bare land. The topsoil moi sture in the bare land was the least among the three kinds of land.

Abstract:The quality of surface runoff modeling is limited by horizontal and vertical accuracy of digital elevation model. Several critical problems and respective solutions are presented. Method of filling pits based on size can distinguish sink cells due to inland catchment from those due to DEM errors. Method combining DEM with stream network leads to a more accurate drainage network from surface runoff modeling, especially for flat area.Method of modifying existing DEM by adding a small value can produce more realistic drainage pattern rather than parallel flow over flat surface.

Abstract:According to the investigation and the analysis on the small watershed characteristics and the summary of the harnessing practice in Zhejiang province, the plan solution to harness small watershed, which is to take the upper, middle and lower reaches of a small watershed into consideration and to carry out the prevention, harness,development and admini stration, has been put forward. The plan outline of harnessing small w atershed,administ ration rule and harnessing criteria has been worked out. The principle of harnessing small watershed and the corresponding measures has been made. The general index system of standard of small watershed harness has been established. The procedure of harnessing project and the administration system has been set up. The types of harnessing small watershed, the model of economic development and management technique are preliminarily analyzed and discussed in terms of the practice of small watershed harnessing within the entire province.

Abstract:With sustainable strategic ideas and theory, the technique, measures and w ays of comprehensive control and sustainable exploitation and utilization of Hengkeng small watershed are studied and concluded. Then the benefits of economy, society and ecology of which are analy zed.

Abstract:Based on introducing the surface mine soil and water loss in Tiefeng mountain of Anxi county, Fujian province, it is analyzed and discussed how to forecast the amount of soil and water loss by catchment unit where there are surface mines in it, then the perfect result is obtained and it is used in fact successfully. On the basis of these, it is suggested that the technique way to control soil and water loss of surface mine, which is forecast the amount of surface mine not only focus on mine area, but also on comprehensive estimate the whole catchment, as well as integral control the whole catchment instead of control mine area itself.