Abstract:The widely accepted Bagnold type function to calculate threshold wind velocity or shear velocity was developed for dry sands. However, surface moisture is an extremely important variable controlling the entrainment process of sands by wind because the tensile force between the water molecules and sand grains produces cohesion. The detailed results from experiments in a laboratory wind tunnel are reported, in which the threshold shear velocities for a range of sand grains with different moisture content are measured. The results show that the functions relating threshold shear velocity and moisture content are different for different sized sands. Relative threshold shear velocity, the ratio of threshold shear velocity of sand at moistened state to that at dry state is better related to moisture content. For given grain size, the threshold shear velocity is proportional to the square root of moisture content.

Abstract:The forest water balance relationships were established based on the rainfall redistribution by forests, water transpiration from vegetal strata, forest soil evaporation observed and measured in site by means of fixed standard plots method as well as ot her co ncerned f acto rs(such as runof f)deduced as balances from the simplified water balance equations. The results showed that the total evapotranspiration ranged from 476.6 to 651.3 mm for the five forest vegetation types in growth season, in which the canopy evapotranspiration was the major part, ranged 476.6～651.3 mm, accounting for 73.5%～88.6% of the total; The forest field evapotranspiration under canopy changed from 69.3 mm to 126.5 mm, making up 11.4%～26.5% of the total; The groundflow depth ranged from 69.3 mm to 126.5 mm, sharing 11.4%～26.5% of the total; Surface runoff did not easily happen in forest fields, and ground flow depth ranged 76.6～263.9 mm, accounting for 10.3%～35.5% of the rainfall amount in the same period. There was much large difference among forest types in water balance components, showing that the total evapotranspiration for conifers was apparently larger than that for hardwoods.

Abstract:The conventional identification of salinizated soil is based on the laboratory results of soil specimen. It can not be applied continuously to the investigating area inch by inch due to high cost and heavy work of dense sampling rate. However, the correlation among Ground Penetration Radar(GPR) information and soil salinity, pH value, organism and water content enable us to formulate a method with which parameters above specified may be investigated. Theoretical study show that the existence of variations in soil chemical and physical properties results in correlated response in geometry and dynamics in GPR waveforms and their amplitude. The field experiment indicates that GPR method would be a feasible technique with fast speed for evaluation of environmental properties of soil salinization.

Abstract:The determination of the velocity in rill flow is the basis of studying the soil erosion. The velocity of rill flow is influenced by flow discharge, sediment concentration, underlying soil and so on. Under the steady discharge, by assuming the resistance of viscosity is directly proportional to the velocity of flow, the dynamic equation of rill flow is deduced. By nonlinear simulation of the experiment data, we obtained functions between velocity of flow and time, the friction coefficient and erosion intensity, and the viscosity force and sediment concentration in flow. The simulating procedure and results show that the model is feasible when the velocity of flow is lower. Velocity of flow is mainly affected by slope and sediment concentration. When the slope is steeper, the velocity enlarges more quickly, but needs more time to achieve steady value.

Abstract:By analyzing the causes of the Sabina vulgris death at the Sabin vulgaris nature conservation zone of Shenmu county in northern Shaanxi province, the component of microorganism community which inhabited the stiffer surface soil layer that appeared on the surface of the Sabina vulgaris sandy soil was studied. According to the characteristic such as the Sabina vulgaris growth feature, the climate in this region, the natural conditions and soon, suggestions and reflections which profit to sand are presented.

Abstract:The new field of urban soil and water conservation passes is studied by designing the best mode of soil and water conservation and environment construction in watershed of outskirts. New scientific ways are presented for soil and water conservation and environment of urban construction in the future.

Abstract:Danjiangkou reservoir is the water source engineering of the Middle Line Project of Transferring Water from the South to the North. There are 53.2 per cent of the total migrants in Nanyang city. On the basis of general analysis of the environmental capacity of migrant in Nanyang city, the planning districts of migrant resettlement are determined, and its environmental capacity is calculated. Some proposals broadening the environmental capacity of migration are made. The planning districts of migrant resettlement are Dengzhou city, Tanghe county and Sheqi county. These districts can accommodate 73197 people. About seventy thousands people should be settled in other regions.

Abstract:SPSS 10.0 for Windows is a large scale statistics software. On the base of this software, the characteristics of groove gradient are discussed, and the relationships between groove gradient and other parameters of debris flow drainage area is analyzed. Especially, the single variable linear regression equation between groove gradient and degree of cutting is set up.

Abstract:The two periods of Landsat TM/ETM⁺ images in 1990 and 2000 are used to dynamically monitor the ecological environment of Dingxi, Weiyuan, Longxi, and Tongwei counties. The background data are obtained through screen visual interpretation. The construction, traffic, and mining land increase by 14.97%. The farming land increases by 8.02%. The woodland increases by 11.23%. The bare land, which is suitable for forest and grassland, and floodplain land decrease correspondingly. In the later 10 years, some measurements are carried into execution, for example, small basin integration control, transferring from cultivated land to forestland and grassland, the balance between grass and animal, and rotation grazing and closing of vegetation, which are results of the rationalization of land use and land cover. But there still consists of some problems such as low land use rate, higher ratio of agriculture land, low ratio of stockbreeding land, low ratio of the trees surviving.

Abstract:New progress trend of supervision regulation has appeared when deeply enforce the law of soil and water conservation environment: (1)The social surrounding is up and up; (2) Preventing and controlling for soil and water loss become socialization, marketability and beneficiation; (3) The executing enactment has changed to administration; (4) The principal policy of prevention is strengthened; (5) The regular construction is developed in high stair; (6) Urban soil and water conservation is emphasized, etc. But there are some problems to be solved, it is necessary to act with the following countermeasures: (1) To execute the regulation by law; (2) To enhance the realization and enforce regulation; (3) To emphasize the principal policy of prevention; (4) To developed the technology of prevention and control of soil and water loss comprehensively; (5) To monitor soil and water conservation, and enhance the level of all supervision and regulation, etc. in order to urge the development for supervision regulation of soil and water conservation.

Abstract:During experimental period, Wudu, in Zhouqu and Wenxian Counties, there had been forecasted 16 times of disaster Successfully and prevented 7021 peoples from injury and death, and reduced the loss of property being equal to 20761500 Chinese Yuan. The ratio between input and benefit is 1:8.65. At the same time, 75 dangerous places of landslide and debris flow were treated in time to ensure 73677 people's life and the property valued 255092000 Yuan safety in the risk area. It is showed that mass monitoring and mass preventing are low cost and high benefit. Through these triales, it not only lowered the degree of the loss on disaster in mountainous area to be smallest, but also probed into the method, accumulated the experiences, and found the way of disaster prevention and reduction, which depends on the station of forecast and warning, which takes mass monitoring and mass preventing as foundation of landslide and debris flow forecasting and warning. It laid a good foundation for popularizing mass monitoring and mass preventing on a large scale.

Abstract:The domain and advancements of vulnerability are concluded. It is believed that the research is weak in aspect of water resource and that the scope should be widened and the academic and applied research should be strengthened. The vulnerability of water resource is redefined to describe the ability of the system to recover its original structure and function when it is damaged. The research scope is widened, and a integrative index system is built to express the vulnerability of water resource, and a quantitative assessment method is brought forward.

Abstract:Grid based DEM is a critical basic geo spatial data base in the analysis of regional topography feature. 1:250000 map scaled DEM is regarded as an important basis for the middle scaled investigation of soil erosion characteristics. Taking three areas of different terrain roughness as test areas, the effective procedures and methodology for the producing of DEM are probed into. In addition, by means of comparative method, the DEM accuracy were investigated, which can be regarded as possessing critical importance for the setting up DEMs, as well as evaluate their practicability and applicability in the field of regional soil erosion research in these corresponding areas.

Abstract:The processing technology of Pugionium cornutum L. flexible package can is determined. The results indicate that Cu²⁺ is a kind of perfect green-keeping reagent which is used to keep the fresh green color of Pugionium cornutum L. in the pH ranged 3.5～4.5. The Ca²⁺ of different concent rations is also used to observe the effect of keeping brittleness to Pugionium cornutum L. The normal temperature pasteurism could meet the needs of Pugionium cornutum L. can commercial sterilization in the soup of can's pH value below 4.5.

Abstract:Based on the theories of landscape ecology, the landscape components and managerial objectives of mountainous watershed are discussed. The principles of planning are pointed out: (1)maintaining and restoring the holistic ecological function of watershed ecosystem; (2)designing optimum landscape structure; (3)remaining the stability of landscape; (4)protecting biodiversity; (5)protecting landscape heterogeneity. Finally, the methods of planning and management are carried out.

Abstract:The problems in designing of the program of Renyi flyover crossing slide treatment are disscussed. The mechanism and intension indices of it are analyzed. The feasibility of each program are expounded by comparing comprehensively.

Abstract:Based on the analysis of regional natural characteristics and the resources utilization status of Jiangsu province, the problems on the sustainable land use and the potentiality of agricultural development are studied. The countermeasures how to achieve the agricultural sustainable development are also proposed. Those are: (1) to strengthen harnessing of the small watershed and transformation of the medium low yield farmland, and fulfill the effective agricultural development model in the hill area; (2) to improve the construction of ecological agriculture demonstration base of innoxious foods, green foods and organic foods; (3) to adjust the agriculture structure and advance the proportion of forestry, stock farming, vegetable and herbage and so on; (4) to strengthen the investment on technology and run up the proportion of technology in the comprehensive development projects of agriculture.

Abstract:The natural condition features of eco system fragility in mountainous orchard of Sanming city are expounded. The reasons of soil erosion and deteriorated eco environment in mountainous orchard are blind development and plantation. The construction standard is low and bring mountainous region under extensive cultivation. The developing direction of eco orchard construction is discussed. The technical measures of eco orchard construction in Sanming city are put forward.

Abstract:The past research on land use change and its environmental impacts, especially those researches on the loess plateau are systematically analyzed. The emphasis is laid on vegetation/land cover change and its impacts on hydrology, soil and biodiversity. The main problems facing in the present research are also discussed, and some suggestions for the future research are proposed.

Abstract:Harmful environmental impacts induced by conventional farming have been recognized by more and more people. Organic agriculture, a new model for farming development, has set itself the goals of environmental pollution minimization and sustainability of agricultural production. In recent ten years, organic agriculture deve loped and extended rapidly around the world. Comparing to conventional agriculture, risks of environmental damage brought by organic agriculture are much less. The objective of this paper is to give an overview of the organic agriculture status and its benefits on water, soil and atmospheric environment, biodiversity and human health.

Abstract:Land use is human activities to get certain economic, environmental and political welfare from land by protection and amelioration. The main driving forces of land use change are discussed from the economic viewpoints. It is thought that the contradiction of land use between the personal and governmental behavior is the main driving force of land use change at present period. The main problems facing in the restoration of environment, and the solutions are also discussed.