Abstract:降水入渗规律的研究可为流域水文过程的预测和评价提供重要的科学依据。通过野外人工模拟降雨的试验方法,研究了短历时暴雨条件下,不同降雨强度对林灌地、封禁草灌地以及裸露农地3种不同土地利用类型下土壤入渗的影响。试验结果表明:不同土地利用类型之间,林灌地和封禁草灌地的土壤入渗速率差异不明显,而与裸露农地之间的差异显著,且前者具有较大的入渗速率,后者入渗速率较小;在不同降雨强度下,林灌地和封禁草灌地的土壤水分入渗速率有随雨强增大而增大的趋势,对于坡耕裸地,随着雨强的增大,土壤水分入渗速率有降低的趋势;通过对试验数据的回归分析,建立了林灌地和封禁草灌地在短历时暴雨条件下的土壤水分入渗经验模型。

Abstract:Three original physiognomy plots (besides bare slope , grass slope and shrubby slope) were const ructed in the Yaner watershed. The amounts of the runoff,erosion and seeping rate in different sections in two years were analyzed. The data were found to vary with different rainfall events. Under the same condition , the amount of runoff on bare slope was 6 times greater than that on grass slope , and 2. 4 times greater than shrubby slope,which indicated that bare slope produced more runoff than other two. The amount of erosion on bare slope was 82 times greater than that on shrubby slope , and 150 times greater than that on shrubby slope. This suggest s that grass and shrubby can greatly reduce soil erosion in the Loess Plateau. Seeping rate varies with all the rainfall event s. Gener2 ally speaking , seeping rate on shrubby slope is 90%,grass slope,85%,and bare slope,60%.It is a comparative advantage in melioration of the Loess Plateau to grow grass or shrub.

Abstract:We studied the water balance of Punica granatum under different conditions of soil moisture management in the micro-catchment afforestation experimental site in the Yuanmou dry-hot river valley.The result shows that the water input of the tree strips of catchment system depends on rainfall and slope runoff,which contribute(90.2)% and(9.8%) respectively,and the water output relies on evapotranspiration.The soil water storage under all the conditions has surplus from May to November.Both the evapotranspiration amount and the water surplus amount under different soil moisture conditions are different.When soil water contents are controlled at 10.08%,(11.63)%,13.23%,14.79%,16.85% and 19.14% levels,the total evapotranspiration amounts are 44.5%,(60.8)%,67.0%,82.0%,85.4% and 87.0% of the water input,and the water surplus amounts are 55.5%,(39.2)%,33.0%,18.0%,14.6% and 13.0%,respectively. It shows that the evapotransiration amouat increases with the increase in soil water content,however,the water surplus amount decreases with the increase in soil water content.The correlation between Punica granatum growing state and soil moisture state is significant.Good soil water condition is beneficial to the growth of Punica granatum and the best soil water content range for it is 14%～15% in terms of water-saving in dry-hot river valley.

Abstract:Moisture physical constants,soil water characteristic curve and specific water capacity of three Caragana Fabr.in typical planting years were studied by contrasting slope plantations and waste hillside fields.Results showed that Caragana Fabr.physical clay content of soil was less influenced,and soil bulk density was improved obviously within 50 years of plantation.Through comparing with soil's holding and supplying water capability in different plantation years,an obvious trend of 46 a Caragana Fabr.30 a and 21 a Caragana Fabr.slope plantationswaste hillside fields was found.Therefore,Caragana Fabr.plantations may promote the development of soil and improve soil holding and supplying water ability.

Abstract:The growth and soil water status of five dominate forests in the sem-iarid region of Loess Plateau were studied. The analysis of the data show d that(1)the growth status of five dominate forests was: Prunus armeniaca> Pop ulus simonii;Prunus davidiana > Seabuckthorn > Caragana kor shinskii.(2) The analysis of different site types showed that soil water content among different site types was: sem-i shady> sem-isunny> sunny.Dif ferent slope directions had a similar changing trend. Soil water content descended with the rise of slope.Soil water content descended below 200 cm, which showed that root absorbing was decline. (3) The average soil water content of different artificial forests was about 8%,which showed the arid characteristic of soil. Totally speaking, soil water content of different artificial forests can be divided into two types. Prunus armeniaca,Seabuckthorn and Caragana korshinskii had a higher usage of soil water, but Pop ulus simonii and Prunus davidiana was lower. The strength of soil water usage was Car agana korshinskii > Seabuckthorn> Prunus armeniaca> Pop ulus simonii> Prunus davidiana.

Abstract:The field experiments were conducted to discover effects of Aquasorb-fertilizer and liquid membrane on soil moisture and growth of Armeniaca vulgaris Lam.According to the experimental results,application of both Aquasorb-fertilizer and liquid membrane could increase soil moisture and enhance the growth amount of Armeniaca vulgaris Lam.in short time.

Abstract:The improving effects of Platycladus orientalis,Robinia pseudoacacia and the two mixed plantations on soil fertility on the Loess Plateau were investigated.In the Loess Plateau area,planting plantation had much help for the improvement of the nutritional element content,such as soil organic matter,total nitrogen,total phosphorus,available nitrogen and quick-acting potassium,and different plantations had different enhancement degrees.Except total potassium and quick-acting phosphorus,every target in nitrogen fixation plantation was higher than that in non-nitrogen fixation plantation.In general,the enhancement of soil fertility in nitrogen fixation plantation is more remarkable than that in non-nitrogen fixation plantation.

Abstract:On the basis of evaluation and calculation on soil water storage capacity in the typical watershed of Chuanhe river in the loess hill area of northwestern Shanxi Province,soil water storage ability in different vegetation and site conditions in the watershed was analysed.The result shows that soil water storage ability in the forestland(especially arbor in shady slope) and grassland is the best,the farmland,the middle,and the wasteland,the worst.Soil water storage ability is different with different site conditions.The analyses of the soil water storage capacity in the different typical precipitation year show that the water storage capacity in ample flow year increases by 9.2% in comparison with that of the normal year,and the drought year decreases by 27%.The water storage capacity after management is 1.5 times the water storage capacity before management in same precipitation year.

Abstract:River and floodplain compose a whole environmental system as they have hydrological and ecological connection,and thus a scientific concept of river-floodplain environmental systyem is established and analysed.The main characteristics of river-floodplain environmental system include the followings: wholeness maintained by flooding,spatial and temporal heterogeneity,openness,complexity and fragility.Flooding plays key roles in maintaining wholeness of the river-floodplain environmental system,and the system responds to process and functions of flooding.The river-floodplain system is enfluenced by both natural process and human activities.

Abstract:In order to understand the herbage biodiversity and synusia structure of artificial forest,we investigated herbages under five forest types of Populus simonii(PS),Prunus armeniaca(PA),Prunus davidiana(PD),Hippophae reamnoides(HR) and Caragana korshinskii(CK).In the 37 herbaceous species identified,only 18,25,20,25 and 17species were present in the PS,PA,PD,HR and CK forests,respectively.For herbages,Stipa bungeana,Arthraxon hispidus,Potentilla multifida and Thymus mongolicus were common in the five plantations.The average coverage,height and biomass of herbages in five artificial forests were different obviously,but community biodiversity was similar.In conclusion,low biodiversity and limited structure development(coverage,height,biomass) under five artificial forests indicate that the environments under artificial plantations are very bad and affect herbage individual development and community structure.Results show that the best herbage community has developed under the Prunus armeniaca forest with a relatively open canopy and low tree density,which suggests that the measures of tree thinning and canopy pruning to keep reasonable density are crucial for promoting artificial forest development,and improving herbage biodiversity and community structure.

Abstract:Through conducting field investigations and using digital methods of remote sensing and geographical information system techniques,we analyzed the dynamic changes of sandy desertification land of the north of Otindag sandy land based on the TM images of 2000 and 2005.The data adopted in this study were composed of two types,namely,census data of 2000 and 2005 and remote sensing(data).The datum source of sandy land and the(data) in 2005 came from the interpretation of composite Landsat 5 images of bands 4,3 and 2(R,G,B) according to the local conditions and land use status of sandy desertification.In order to minimize possible interpretation errors,a set of interpretation indicators was established based on field investigations.The area measurements of these types were made using the statistics function of GIS.Results indicated that the development and reversion of sandy desertification co-exited in the study area,and the area of sandy desertification land increased by 1 366.057 from 2000 to 2005.In terms of the extent of sandy desertification,the area of the light sandy desertification increased 239.806 km²,the area of the moderate,1025.393 km²,and the area of the severe,850.396 km².However the very severe sandy desertification decreased 749.539 km².In terms of the administrative region,the areas of sandy desertification land in Sonid Youqi,Sonid Zuoqi,Abga Qi,Xilinhot,Hexigten Qi,Xiujimqin Qi were 1 038.377 km²,185.487 km²,15.715 km²,51.554 km²,(5.492) km²,69.431 km²,respectively and area of sandy desertification land in Linxi had not clearly changed.In general,the status of sandy desertification in the North Otindag sandy land is still serious.

Abstract:For investigating the changes of sediment yield reduction by soil conservation with spatial scale,this study collected data of the areas implementing soil conservation measures and the amounts of sediment yield reduction associated with soil conservation measures for 64 catchments with different sizes in the middle Yellow River.The soil conservation measures in discussion include land terracing,tree and grass planting,land creating behind sediment-checking dams.Results show that the reduction of specific sediment yield due to implementation of soil conservation measures does not present a significant trend of increase or decrease with the increase of catchment size.

Abstract:Researches on the 0—20 cm surface soil in a long-term experiment of soil and fertilizer at the First Station of Agricultural Cultivation of Northwest University of Agricultural and Forestry showed that easily released phosphorus of various fractions had a close positive correlation with total phosphorus(TP).The ability of soil releasing phosphorus reduced as pH increased,and the buffer capacity differed in different treatments.The releasing ability was also related to TP.Total phosphorus of surface soil had a significantly positive relation with PSD.So,the PSD of 25% of the soil was considerated to be a predicting index,and TP of 1.92g/kg could be used as sensitive environmental index which would predicted phosphate leaching in Guanzhong Plain soil.

Abstract:As one of mountain hazards,sand-sliding hazard usually endangers severely transportation,industrial and agricultural production and our life and property because the frequency of their occurrences is high.Mohr-Coulomb criterion and energy conservation law were applied to deduce the sliding critical condition and rolling condition of single sand.The restitution coefficient was applied to describe the impact problem.The research findings may help to understand the formative mechanism of sand-sliding hazard and control of sand-sliding hazard.

Abstract:The purpose of this research was to put forward reasonable compensation standards and its executive methods to offer the scientific basis for the establishment of a rational system of Western China's Cropland Conversion Program Management.Based on the detailed analysis of the key problems of ecological compensation,detailed contents of ecological compensation were divided into five subdivisions according to the executive steps of a realistic program,i.e.,compensation for farm land loss,structure transfer of agriculture,young seedling and other relative inputs,planting and management,and ecological income.Then more advices for policy were presented.Results show that the new compensation methods are scientific,effective,impartial,and practical.

Abstract:Soil erosion is one of the widespread crises in China.The problem has caused water and soil resource destruction,eco-environment degradation and so on.Moreover,soil erosion is one of the main reasons for regional poverty.By statistical approaches,this paper presents that there is a kind of coupling relationship between the region of soil erosion and the distribution of poverty population.The relationship is characterized by the following aspects.First,eco-environmental degradation can induce soil erosion.Second,soil erosion is the fountainhead of eco-environmental degradation and poverty by restricting the significant use for limited resources and increasing environmental pressures.Third,further poverty can also accelerate soil erosion and eco-environmental degradation.Under such considerations,it is necessary to pay more attention to soil and water conservation projects in order to realize the sustainable resources utilization of water and soil.If so,the eco-environment can be improved,the people's income can be increased and the poverty will be alleviated step by step.

Abstract:The karst area in Guizhou Province was classified into five eco-economic categories by the principal component analysis and fuzzy poly-class method.Firstly,classification index system was set up,then was selected in 22 original variables by the principal component analysis.The 75 counties in Guizhou's karst area were classified into the five eco-economic category.The results from this research could present scientific basis for the emphatic drawing up of sustainable developing strategy.

Abstract:By taking soil and water conservation monitoring of the Yangzi River Dike reinforcing project in Jiangxi Province as an example,the scope,contents,methods and results of the monitoring were introduced in detail.Soil and water conservation circumstance was monitored and evaluated before,during and after the project development.It is found that soil erosion is efficiently reduced in the dike development by using the measures of soil and water conservation and the degree of soil erosion influence is remarkably lowered.As a result,the ecosystem environment along the dike is well protected.

Abstract:Neighborhood analysis calculation with 3×3 window is usually adopted to derive slope f rom Grid DEM.This method produces errors on the edge of terrain factors mat rix.This paper takes slope as an example , three areas with different terrain characteristics as test areas, studies the edge effect on deriving slope from DEM with different scale , analyses the relationship between the edge effect and DEM resolution, region area and terrain characters, puts forward some methods to solve or decrease impact of the edge effect .It is important for digitalterrain analysis with high precision. There are two indexes to express edge effect:the first is the change value of mean slope;the second is root mean square error on the edge when deriving slope. The result shows that, the change value of mean slope is related to DEM resolution,region area and terrain characteristics , RMSE on the edge when deriving slope is related to DEM resolution and terrain characteristics.

Abstract:The integration of hydrological model system with GIS and remote sensing technology will be the prevailing trend in the study of hydrological cycle or processes in the future.The main purpose is to simulate the productive mechanism of runoff over the Baohe catchment located in the upstream of the Hanjiang River using hydrologic modeling system HEC-HMS,which includes several kinds of modules.Then DEM,soil data,landuse and landcover are processed synthetically using Geo-HMS(extended module of HEC-HMS),which can be embedded in ArcView3.2 software,and some important parameters in this hydrologic model system could be gotten.In succession,a sort of watershed modeling scheme with network elements is established after selecting and integrating the simulated algorithms of each hydrologic process.The result shows that the simulated flow agrees well with the observed flow at the Jiangkou station,the outlet of the Baohe catchment.

Abstract:Soil aggregate stability is a key property of soil,and reflects soil fertility.Soil aggregate stability index(ASI) was formed through the transition matrix between dry sieving results and Yoder method results,and conserving-probability of each size aggregate on the basis of 3 reasonable assumptions.The ASI is identical to the result by references,which shows that the transition matrix can be used to evaluate the soil aggregate stability.The transition matrix was then used to analyse anti-break ability of different size aggregates.Results show that there are difference effects for each size aggregate with 4 methods of simulation rainfall,wetting-drying cycles one time,wetting-drying cycles ten time,and Yoder wet sieving.There is a good linear relationship between content of more than 0.25 mm water stable aggregate and ASI in a total tendency,but not all size aggregate stability heightenes with 0.25 mm water stable aggregate content increasing.The transition method utilizes all information of aggregate analysis,and can be a better tool to understand soil aggregate.

Abstract:The volume of terrain deformation caused by debris flow can be calculated by the multi-temporal DEM derived from aerial-photography only when they are in common coordinate.This paper introduces the technique of 3D surface matching without using control points.A new algorithm,Multiply Surface Patches Matching(MSPM),is proposed to match the two temporal DEMs.The experimental results on real data sets show that MSPM is more appropriate for DEM matching in debris-flow area and has higher accuracy than that of M-LZD algorithm.

Abstract:The characteristics of pipeline engineering construction and the soil and water erosion caused by it are analyzed. The emphasis of soil and water monitoring of pipeline engineering is ascertained.Taking the Second Gas Transportation Pipeline Engineering From Shaanxi to Bejing in Shanxi Province as an example,the technique route,the monitoring index system is ascertained and each one's monitoring methods are put forwards.The monitoring result is analyzed.

Abstract:Slope debris flow is a natural hazard constantly observed in the mountain area. Taking the Beibei of Chongqing City as an example,the paper analyzes the self-organization criticality of solid loose materials,and the criticality of geomorphology and rainfall while slope debris flow occurs.From viewpoint of self-organization(criticality),non-linear interaction exists between different subsystems in the formation of slope debris flow,and causes the system to develop naturally to a state of self-organization criticality.Under triggering by storm,slope debris flow occurs eventually.There exists a power correlation between its magnitude and frequency,which is a behavioral sign of debris flow as self-organization.In addition,occurrence law of slope debris flow can be predicted and forecasted through the power correlation.

Abstract:By the use of Frastrates 3.3,some landscape indices representing the landscape expression were calculated for the landscape expression of construction lands at the landscape level and class level on the basis of the description of the landscape pattern of Beijing mountain area.The change of landscape pattern of construction land was analyzed using these indexes.Results show that the ecological construction brings about the continuous increase of green space,and the landscape change had a trend of simplification and homogeneous,which will result in a compartment pattern.As for construction lands,their shapes are more fragmented and anomalistic,and the neighboring probability is increased among the patches.The landscape function is turbulent as the shape takes on a change trend of no disciplinary.A deep exploration of landscape pattern indicates that both town land and factory land are being concentrated.However,the pattern of rural residential land is still dispersive,and even become worse.Factory land has not formed its gathering efficiency,and the construction of transportation is the key whether the town can bring its role as a growing pole into play or not.To realize this,being guided by a scientific land use planning is a necessity.

Abstract:Returning farmland to forest is an effective measure to control soil erosion in Guizhou Province.Analyzing the quantity of the slope farmland,especially the proportion of farmland to the territory area,is an important foundation for making the strategy on the returning farmland to forest.On the basis of probing into the present situation and factors of slope farmland,this study classified the 82 counties into seven levels and three categories,taking the proportion as the urgent index of returning farmland to forest.The important region was found to be the region of the utmost key type and the key type of returning farmland,which covers 56.63 percent of the territory of the whole province.Therefore,it may achieve 75.39 percent of slope farmland to forest.As the same time,this paper presents the principle of the ratio of the grove species deployment.

Abstract:The spatial distribution characteristics of regional soil and water loss are affected by geological scale greatly.Based on the special geological conditions,the paper gives an analysis on spatial distribution properties of soil and water loss in Guizhou Province,and gives the detail description for each area.The result of this study will be a scientific foundation for macro treatments of soil and water loss and for layout of soil and water conservation and eco-environment construction.Meanwhile,the result will provide an idea for soil and water loss research.

Abstract:On August 11,2005,an extremely wide debris flow disaster with return period of more than 100 years took place in the Hailuo Valley,Luding County,the east of the Gongga Mountain.After investigation of the disaster, the causes of the disaster occurrence,including geology,relief,climate and human activities,were analyzed.The main cause to the occurrence was the heavy rainstorm.The amount of daily rainfall was over 88 mm on August 12.The trend of debris flow activities was analyzed by referring to historical debris flow.Controlling countermeasures such as emergency measures and upper mitigation measures are presented through comparing the 050811 hazard with other hazards like the debris flow in Xinping County.

Abstract:The author divided the dominant plants and leading associated plants of vegetation on coastal wetlands in the Yellow River Delta and the Southern Laizhou Bay into three eco-adapted types of halophytes,hydrophytes and amphiphytes,and compared the differences of vegetation types,the distribution and evolvement of the vegetation there.The dominant plants of vegetation on middle and high tide foreshore wetlands in the Yellow River Delta are halophytes such as Suaeda heterobtera and Tamarix chinensix,and the vegetation on coastal wetlands in beach are fresh water marsh and meadow where the dominant plants are hydrophytes and amphiphytes such as Phragmities Communis,Typha orientalis and Aeluropus littoralis var sinensis.The vegetation has evolved rapidly into bare tide foreshore,salt marsh in tide foreshore and beach,fresh water marsh meadow and farmland in the latest 30 years.Much of vegetation on the wetlands has been replaced by artificial wetlands.There is no vegetation on tide foreshore in the Southern Laizhou Bay,but there are salt marshes in beach where the dominant plants are halophytes such as Suaeda heterobtera,Suaeda glauca and Tamarix chinensix.Salt marsh and fresh water marsh have evolved into meadow,and much of vegetation of salt marshes in the Southern Laizhou Bay has disappeared due to the construction of saltern and ponds of shrimps and crabs in the latest 30 years.

Abstract:Comprehensive management of small watershed has been a main type of controlling soil and water loss in the world today.With rapid upsurge and wide spreading of the sustainable development theory,the manner of comprehensive management of small watershed has been fundamentally changed from the forms of simple prevention and protection in the past to those of comprehensive management,use and protection today,and presents the tendency of approach to the orbit of sustainable management.The concept of sustainable development of small(watershed) was put forward based on a deep definition analysis of sustainable development and the small watershed comprehensive management.Several key questions about how to realize sustainable management of small watershed were emphatically explained.Authors' aim was to give rise to more attentions to the questions by academic circle and deep research on sustainable management of small watershed.

Abstract:Compared to the soil in cereal cropland,the physical,chemical and biological properties of the soil in the protected field,such as organic matter,total N,available nutrient(N,P and K),exchangeable Ca and Mg,(acidity) and alkalinity,salinity accumulation and bio-activity,have obviously changed with the prolongation of cropping duration.This has decreased soil quality,impacted crop growth and potentially threatened human health.In order to sustain the vegetable production with high yield,high quality and high efficiency,it is of great theoretical and practical significance to study soil fertility and its affecting factors in the protected field cropping system.