Abstract:Red soil erosive area is the key region of soil and water conservation in Guangxi Province.Based on research and investigation,the approach of ecological reconstruction is studied by selecting fine soil and water conservative plants disposing method in the erosive region.After 5 years experiment,the results show that the complex model of agriculture and forest which combines arbor with shrub,grass and vine can not only control soil erosion,but also restore eco-environment.The vegetative coverage increases from 10%-30% to 60%,runoff amount and sediment yield decrease more than 70% and 90% respectively.The soilfertility significantly increases,and the content of N,P,K increase by 2.72%-900%.The eco-economic benefits is significant.

Abstract:According to data of overland flow from runoff plots which represent various rainfall collecting and data of soil moisture from determined positions periodicaIly,the relationship between soil moisture envoirnment and water-harvesting afforestation techniques and rainfall utilization of trees,water balance on afforested lands are analysed in semi-arid loess region-The results show that water-harvesting for afforestation greatly increase rainfall use efficiency of trees and also improve the c0ndition of soil moisture.

Abstract:The initial 5-years benefits of newly built protective forest are studied in this paper.The results show that the canopy interception coefficient is up to 19%,runoff rate ofoverland flow decreases by 10~19% and the soil water storage capacity increases 90% than slope wasteland in the early two years.The annuaI sediment yield is decreases 10~70% in the third year and will be up to 70~90% in the fifth year after the protective forest has been built.At the same time,the benefits of protective forest will increase along with forest age prolonging.

Abstract:Starting from the aim of soil and water conservation,the author thinks that an intergrated protective system for soil and water conservation should consist of vegetation building,runoff adjustment,prevention and economlcal development.They penetrat and influence each other,and make up an organic system.Through studying and aiming at the actural condition,the comprehensive protective system of small watershed sitLlated in this region is analysed and sumed.

Abstract:Landslide activties in this area can be obviously divided into four active periods,each of them corresponds to Bailong River's downcuttlng tirne.The most active gelilgic elements of the landslide are silurian phyllite,slate and schist and their activity index are up to 0.8326.According to the frequency of landslide,its altitude above seaulevel and the naturepropety of rock stratum,the stabilities of slope areas are classified.

Abstract:Water calamity,a kind of natural or artificial calamities related to water,is created by over or less water,flow energy,chemical compositions of substance in water,or interaction between water and its medium.Water harm generally means flood and drought.Extensive meaning of water harm also include water and soil landslide,debris flow,artificial water harm and so on.The reasons that cause water calamity in eastern region of Qinghaiporvince are discussed in this paper so that more attention should be payed to the water harm in this area' The prevention and control measure for water harm should be strengthened,and researches should be concerned.

Abstract:Since 1980,the program of comprehensive soil and water conservation harnessing and expeloiting experiments in 144 small basins and 4 stages have been put into effect in upper and middle reaches of Yellow River by government,very good benefits have been obtained.Today,most of the basins have been the examples for the local soil and water conservation and models of breaking away from poverty and becoming rich to a relatively comfortable life for local people.Taking the market as the guide,the conduct experiments should expeloit and study the ways to continuously open up the investment channels and develope soil and water conservation production,strengthen the comprehensive developmental ability in small water shed,finally realize the sustainable development.

Abstract:On the base of summarizing the cause and treatments of the no-flow in the lower Yellow River,the key aim of this paper is to explore influences of comprehensive control inLoess Plateau on water cycle of Loess plateau and no-flow in the lower Yellow River.Effects of vegetation,high yield of crops,construction of terrace and dam-sludge-land on heightening in small cycle of water and weakening in large cycle of water and reduction of runoff in middle reaches are given in depth analysis.At the same time it is pointed out that a part of water used to wish silt away can transform into use in the lower reaches.Therefore,it is suggested that general effects of comprehensive control in Loess Plateau on water resource in the middle and lower yellow r1ver should be studied deeply.

Abstract:Ecological degradation research is one of the focused problems of today's ecology.A review of ecological degradation study and analysis on the concepts of degradation including soil degradation,land degradation,desertification and eco-degradation are given.The eco-degradation is divided into three levels:(1)single ecological factor;(2)natural ecosystem;(3) social-economic natural complex ecosystem (SENCE ).Finally,the study scope of eco-degradation is presented,which-includes:(1)theory and methodology of ecological of degradation;(2) mechanism and process of eco-degradation;(3)quantitative evaluation of eco-degradation;(4)prediction and systematic monitor of eco-degradation;(5)restorationand reconstruction of eco-degradation.

Abstract:The potentiality of increasing grain yield is restricted by drought,poor soil and bad ecologicdl conditions.Therefore,storaging water and cultivating land to improve the quality of land,and taking comprehensive technique to improve the ecological environment can lay a steady foundation for continued development of grain yield in"the two north regions.

Abstract:The necessity of developing rainfall collecting in Loess Plateau,advantageous conditions, components of rainfall collecting,effeciency of rainfall collecting slope,main types,structure,investment and benefits of cellar are deeply analysed in this paper.