Abstract:The history, the current situation and the prospects of level terrace which is transformed from cultivated land in Gansu province are expound.The cultivated slope land resource and its distribution, the constructive condition, the experiences and efficacies etc.of level terrace are analyzed synthetically.

Abstract:Based on the analysis of loess landforms division and its evolution, the law of added erosion is discussed.The result shows that the accelerated erosion power equals to the sum of natural erosion capacity and the added erosion ability.Then, the principles of controlling soil erosion are also discussed.

Abstract:The silk fabrics sales volume on current market of China and abroad is tending to increase.Export exchange earnings of natural silk achieve 3 X 109$per year for China in recent years, and fourty percent of the natural silk turnover in the world trade is owned by China. Planting shrubby mulberry on steep slope barren land of more than 25 degrees with new artistry on ridge-trough cultivation of shrubby mulberry on steep slope land.There are 9000~18OOOkg of mulberry leaves per ha that could be produced at hilly region of Shaanxi province;there are 450-900kg of cocoon crop and 300-600 yuan of income that could be obtained from 15~30case of silkworm eggs raised with per ha shurb by mulberry leaves, and 6000-12000 yuan of soil and water conservation benefit per ha could be produced.There are 9.22 X 10⁵ha steep slope land of more than 25 degrees in Shanxi province.On these land, cereal crops must not be cultivated according to Chinese soil and water conservation law.There are 4.33 X 10⁵ha of shrubby mulberry on rideg-trough field could be developed, which will not share the land with grain and other economic crops.Agricultural, industry and business tax could be achieved to the amount of 1.53 X 10¹⁰ yuan.At the same time of gaining foreign exchange for homeland, 2.6X10⁹~5.2X10⁹yuan of soil and water conservation benefit could be gotten.

Abstract:Taking the typical eolian sandy soil from Liudaogou micro-river basin of Shenmu county, north Shaanxi, the influence of moisture on the resistance of studied soil to wind erosion is ascertained by means of wind tunnel experiment.The conclusions reached are as follows:the threshold wind erosion velocity of eolian sandy soil increases linearly with an increase of moisture content;the wind erosion rate(intensity)reduces with an increase of moisture content by the sec-and power function.A comprehensive moisture-based model suggested for the resistance of eolian sandy soil to wind erosion has be obtained.

Abstract:Based on the field to 1994, monitoring data in loess hilly and gully area in northwest Shanxi province from 1992 to 1994, the available water, the water cycle model and water compensation of the soil under different vegetation conditions-Caraganakorshinskiishrubbery, cropland and wasteland are studied.

Abstract:The effects of applying CCC solution to wheat seed soaking upon the water and fertilizer use efficiency of dryland winter wheat are analyzed based on the simulating experiment and the¹⁵N-trance technique.The results indicate that the application of 1 jo CCC solution to seed soaking can increase the weight of root in deep soil layer (below 70cm)by 86.4%.To add nitrogen fertilizer with the spring rain.seed soaking in CCC solution can increase the ability of wheat root regeneration and nitrogen utilization by 20%higher than that of the contrast, and it can increase wheat seed production by 16.4%.Thus, it is an effective measure to raise the water and fertilizer use efficiency on dryland winter wheat by the application of soaking seed in CCC solution in connection with nitrogen fertilizer application in spring rain.

Abstract:The soil loss.sediment yield and process as well as soil anti-scourability were tested on field artificial runoff plot and undisturbed soil sampling(lOcmX20cmXlOcm)under the same conditions.The result showed that soil sample washing method was 200-400times of soil loss than in the runoff plot in 15 minutes with rainfall of 0.65 and 0.84 mm/min.The erosion process in soil sample washing was different from in runoff plot.The runoff depth in former was 50~150 times and erosion modules was 5-7times(bare land)and 1.8-4.5 times(pasture)of in runoff plot.The reason of such difference was analysised.It was also found that there exited relation of sediment yield between samples of large size(lOcmX20cm XlOcm)and small size(3.5cm X 20cm X 4cm), and sediment yield in former can be estimated by small one.

Abstract:The relation between the growth of Chinese pine(GCP)and climatic factors(CF)is analysed by using multivariate regression，The results showed that Chinese pine is a kind of tree which respond sensitively to CF.There are mutual effects among CF.and CF effect GCP to- gether.The dominant CF which influence on the successive annal grownh of heigh, diameter and volume of Chinese pine are precipitation and ≥10C accumulative air temperature;precipitation≥10C accumulative air temperature and sunligh hours;precipitation, sunligh hours and≥10C accumulative air temperature，respectively.

Abstract:Based on the reviewing of the current research state of energy input and output at small watersheds in loess plateau region and the study conditions abroad and in home, the basic conditions in nature and input-output of energy in the study area were analysed, from this the study procedure for energy flow analysis was set.which includes scope determination, subsystem division and survey energy calculation, indices analysis and energy flow figure.Taking Huangjia Ercha watershed as a research subject.the capital structure of small watershed system was established and the calculating method for energy flow was made.

Abstract:In the gully region of loess plateau.among geographic and soil factors influencing the locust tree growth, soil moisture is the main factor.And soil moisture is influenced mainly meteorological factors.When meteorological factors influence the locust tree growth, the mois-ture factors'are more important than the heat factors.

Abstract:Under very dry condition, the winter wheat roots in cultivated soil layer withered in spring, the epidermis, except the vascular tissue, damaged. This showed that the roots lost their absorbing ability.The roots in deep soil layer have the absorbing ability because the deep soil layer is damper, but the water and nutrient that absorbed by the roots in deep soil layer can not meet the need of wheat growth and development.for the roots and nutrient in deep soil layer are less than those in cultivated soil layer.So, the yield was very low.After the rainfall in the turn of green stage and jointing stage, the damaged roots can not recover, but winter wheat has the ability of producing new secondary roots to recover its absorbing ability.In this stage, the root system had strong compensation absorbing ability.Thus, it is an effective measure to raise the effects of water and fertilizer on dryland winter wheat through applying nitrogen fertilizer in spring ram.

Abstract:The second phase project for the major administration of soil and water conservation in Yellow river basin is accounted summarily.since it is implemented in 1993, the quality, the scale and the criterion have been continuously improved and the benefits more obviously, for the state has attached more importance to soil and water conservation work.Meanwhile, the new situat lon, new characteristics and new problems during the major administration are analyzed.Then, the exist problems are found, and the corresponding countermeasures are formulaed.Therefore, an important instruction is provided for the mayor administrative work and the economical development in the future.