Abstract:According to the experimental practice of soil and water conservation of small watershedin the upper and middle reaches of the Yellow River,the paper systematically exploited the hotpoint of soil and water conservation for developing small watershed economy.Developing small wa-tershed economy will make much more positive function to enhance intemal vitality of soil and waterconservatoin, to raise land productivity and make peasants get rid of poverty.In the meantime,thereare many favourable conditions.So the opportunity of dovcloping small watershed economy tends toripen.In the course of practice, we must make great effort in changing ideas, disposing resources, in-creasing scientific and technical level,and doing well in public services.Thus achievements will beobtained.

Abstract:Sinomonium acutum var.cinereum (Diels) Rehd.et wils is a wild plant resource and onlyexists in China.it especially deserves to be exploited in the Qinlin and Ba mountain and thes south-west mountainous area of China.in this paper,the important and special roles of this plant in en-abling mountainous people's to eliminate poverty and get wealth,finding ways for the surpluslabour,mitigating the serious shortage of raw materials,soil and water conservation and restoringthe ecological balance are thoroughly discussed under the subjects of sinomonium acutum var.cinereum (Diels) Rehd.et wils economic,ecological and social benefits.The present state of the ex-ploitation and utillization of this plant in Shaanxi province and the problems relation to how to do-mesticate the plant into a cultivated cash crop are also expornded.

Abstract:Based on the field surface shallow flow experiments,the roughness coefficient value (n)on different land have been quantitatively demonstrated by changed Manning Formula in this pa-per.The result shows that the relationship of roughness coefficeint value(n)to litter and grassamount appears to be an orthographic correlation on forest land.And the order of roughness coeffi-cient value (n) from lower to higher on different condition of land use is as follows:soil road,cultur-ing land,walnut plantation,the land of artificial locust forest,the land of shrub forestry and theland of artificial Chinese pine forest.This paper deals also with the relationship between roughnesscoefficent value(n)and the infiltration of water.the preliminary result shows that the higher theroughness coefficient value (n) is,the more the infiltration of water will be.

Abstract:The experiment was carried out at the land shrub forest(Caragana korshinskii,Hipphae rhemnoides,Prunus davidiana) from 1991 to 1994 at Shanghuang Experimental Feild inGuyan county.This paper studied the daily changes of transpiration rate at growth period and theend of growth of three species,and the relationship between these changes and enviroment factor.Itwill contribute to understande demaned of water of different species of shrub at semi-arid condi-ton.and provide the scientific basis for energetically developing and reasonable managing shrub for-est, and also for bring ecological and economic benefits of shrub forest into full play.

Abstract:Field trials were conductded by using the regression design of quadric orthogonal rotationin southern ningxia hilly area.By means of establishing mathematical model, this paper analysisedthe input of N, P₂O₅ and seeding rate.The relationship among N, P₂O₅,seeding rate and yield wasset up,with which the optinal medel for flax cultivation vvas set out.The model gave the inputamount of fertilizer and seeding rate according to rainfall style.They were that:in ordinery rainfallstyle,N is inputed by 96.4kg/hm², P₂O₅ 92.7kg/hm²,seeding rate:55.2kg/hm², and the yieldwould be 1921.3kg/hm², Under the drought style: N:101.2kg/hm², P₂O₅:102.6kg/hm², seedingrate:56.4kg/hm², and the yield would be 1 568.2kg/hm².The optinal model would be very signifi-cant for improving flax yield in practice.

Abstract:The paper has analysed the data of check dam from typical small watershed and key trib-utaries in middle reaches of Yellow River.The conclusion has made that sediment reduction actionby check dam is obvious,and erosion redution is also notable.1.Check dam is major measures forgully control.Sediment reduction by dams approximately take 60%～70% out of the total by soiland water conservation measures;2.Silting in dams raise the erosion base.This can prevent guilybed from cutting down,and banks from expanding;3.The development potential of check dam isgreat in middle reaches of Yellow River.It is necessary further to do dam system planning reason-ably and increase input.

Abstract:Based on the experiment data of field simulative rainfall,the seasonal change of coverageof two years old artificial grassland of Astragulus adsurgens and Melilotus albus and their benefits ofsoil and water conservation were analysed and discussed in this paper.The results are showed as fol-low the seasonal change of coverage was power distribution;the correlation are exponent functionbetween coverage and the time of runoff beginning,or runoff amount,or sediment yield seperately,the peak value of coverage of artificial grassland appeared at the same time as the peak value of year-ly rainfall dstribution appeared.Meanwhile,bacause of high coverage,the benefit of soil and waterconservation was very good.

Abstract:With the development of remote sensing techology system,The application of the mi-crowave remote sensing and GPS(Globe Positioning system)have become two hot spots,Not onlygiant society and economy benefits have been obtained but also traditional technology methods inmany fields have been changed thoroughly.This paper brifely introduces the microwave remotesensing and GPS and discusses imitially Its applicating in the soil erosion monitoring.

Abstract:The surplus substains and energy have been calculated throungh put forward the con-cept of systematical capicity of soil and water loss and given the formula for calculating surplus ener-gy, in which contains all the factors affected of soil and water loss and its amount unit is harmo-nious as the hase establish equation of forecaste and prediction soil and water loss.

Abstract:Based on discussing the conception of social forestry, eco-economic characteristics of themodels of intercropping tree with grass were stated in this paper,and the significance of the modelsin aspect of solving the shortage of“three materials”in the loess hilly areas was illustrated.It wasshowed that there would be a good production prospect in intercropping tree with grass. Based onthe emphasis of production management, the models of intercropping tree with grass might be divid-ed into three types,the type of taking tree as the dominant factor,the type of taking grass as thedominant factor,and the type of balance of tree and grass.By approaching the existing problem,theauthor thinks that the further research for construction and management of the models will be nec-essary.

Abstract:The law of the variation of the soil water in low Taihang mountainous areas of gneiss ofHebei province as well as the effect of terraced and trenched field with slope on the law were studiedby means of fixlocation experemental observation and resonant wave analysis.The results showedthat the variation of soil water content showed obvious periodicities because of the effect of precipi-tation and evapotranspiration,etc.Terraced and trenched field with slope increased the average valueof the soil water content seqence,reduced variation,delayed maximum and minimum value and en-hanced drought resistance because of thick soil layer,high accumlation of runoff and retaining wa-ter.