Abstract:The hysteretic effects which have been discovered and studied in the soil-plant-atmo-sphere continum are the moisture characteristics,the hydraulic conductivity characteristics and the rate of water flow in plant-water potential relationships.The actual phenoma of cosiderable hysteresis characterizing the hydraulic conductivity-capillary head relationships,and the less significant hydraulic conductivity-moisture content hysteresis,is proposed.The theories and predicting models of hysteretic effects are reviewed in this paper.The problems and new taskes are discussed at last.

Abstract:Under the current situation,the work of scientific and technical information in soil and water conservation should be conducted in accordance with the equirement of research work when determing the collecting content;the information should be exploited in multiple ways,based on which the secondary data is well made to raise use rate of the scientific papers;the available condition is fully employed to develop information investigation and study.It is suggested to enhance the information sense to make the work enter the society,to impoove the work conditions to accelerate the information transformation.It is important to optimize the structure of work staff and to increase speciality quality.

Abstract:As early as the beginning of 1950s,there has set up organizations of scientific research on soil and water conservation in Shanxi province.At present,there are 6 scientific research stations/institutes with about 50 engineers and senior engineers at prefecture and provincial level,and they have achieved more than 100 scientific research results,more than 50 of them have won prizes of prefecture (city),provincial (ministry) or state level,bringing notable economic benefits.In order to suit to the development of market economy,they have completed several reformations.They need further change their concepts to fully utilize the existing superiority of people of talent.space,instrument and equipment,and to strengthen the capability of stations/institutes themself.

Abstract:Through constructing ecological agriculture with commodity economy,the relation between man and nature can be coordinately developed,the relation of "man-nature-society"may be rationalized,and it is a effective way to combine measurements of soil and water conservation with agricultural production.As a result,to construct ecological agriculture with commodity economy in the loess plateau is very important.

Abstract:Based on the method of sand particle groups analysis,we deal with the sediment production on different sloping lands and the sediment transportation in gully in the granite region in Xia Anxi watershed of Three-Gorge of the Yangtze river.The results show that the maximum in accumulating content of sand particles (diameter<2.00 mm) is the mixed forest land and the pines massohiami forest land,the middle is the uncultivated land and the minimum is the terrace and the cultivated sloping land.The terrace and the cultivated sloping land is the main source of soil erosion and sediment production in the granite sloping land.Every section in the gully has the sand particle distribution of all diameter classes on sloping land.The sediment delivery rate of main gully approaches 100%.

Abstract:It is showed by many studies that vegetation has very strong effect on water and soil conservation. When the total vegetation coverage density of plant community is great than 40%,vegetation can diminish more than 50% of the total soil erosion with respect to naked land.If the total coverage density of plant community is great than 80%,vegetation will basically control all the soil erosion.Now,under the condition of human disturbing,the real vegetation coverage density on loess plateau is generally lower than 40%.If there were no human action of clamate and geology,,under the same condition the total vegetation (whether forest or steppe) great than 80% on loess plateau according to the ecologic theory and the coverage density would be remnant good vegetation in some rare areas on loess plateau.Through the comparison of the real vegetation and the possible vegetation under the condition of no human action to all kinds of land,we come to the conclution that the accelerated erosion by human action is about 90% of the total erosion at present on loess plateau.

Abstract:The main erosion strains in Shenfu-Dongsheng coal mining area are wind,water,gravity and human activities.The erosion strains have two features,that is,wind erosion and water erosion change periodly with the alternation of seasons and interlance with each other spatially.The interation of wind erosion and water erosion,as well as the process of erosion,transportation and deposition of earth surface caused by erosion strains have formed special micro-landforms on slope surface and vertical erosion belts.

Abstract:In this paper,the malan loess on Guanzhong area in Shaanxi province has been studied and a mathematic model of correlation between water content and matrix suction of unsaturated loess has been obtained through the analyses to the measured results of experiment.Analyses show that the mathematic model can excellently demonstrate the relation between water content and matrix suction of Malan loess in a large varying range of matrix suction.

Abstract:We give a introduction to a few calculating methods on fall velocity of water drops at home and abroad at present.The virtues and defects of these methods have been compared.And a calculating method which is fit for artificial simulated rainfall has been chosen.

Abstract:By using data of rainfall and hydrologic sediment,the characteristics of erosion and sediment generation at Toutui river watershed in the Xinjiang Uygur Autonomous region is analysed systematically.The majoy types of erosion in Toutui river watershed are erosions of water,wind,gravity and man-made accelerated which resulted by irrational soical and economical action of mankind,specially,water erasion is the primary type of it.The characteristic of water erosion there,is erosioning by water of melted glacier and snow.The erosion and sediment generation show obvious variational characteristic of time and space.The region in elevation of 800一1 400m,the vegetation is shorter there,it is the main region of sediment generation.The main period of erosion and sediment generation is in Period of month 5th一8th.

Abstract:By application of statistic theory,we provide experiment formulas of rainfall-runoff and rainfall-sediment for different branches based on the study of regulation on runoff and sediment discharge of main twelve branches located in Weihe watershed and statistic analyses of rainfall,runoff and sediment data.We apply the formulas to calculation of the benefits of decreasing runoff and sedinvent of control measures of soil and water conservation under each branch from 1970s to 1980s,a reliable preliminary result has been obtained.It provide scientific basis for control planning,reasonable development and utilization soil and water resources.

Abstract:In the 4 areas with soil and water loss in middle reaches of the Yellow river.the developping of production and the prosper of economy is seriously restricted by factors of adverse natural condition,weak ecoenvironment,arid climate,soil and water loss,poor life of the peasants and undeveloped economy. As a result of comprehensive harness for 10 years.the benefits is very notable by vigorously promote the founditional construction of field,planting trees and seeding grass.regulating the structure of land untilazation,improving funditional installation and developping commodity economy.The benefits of soil and water conservation and economy is notable,and the living standard of peansants is obviously raised.