Abstract:The project,“Research into soil erosion processes and control in the major water erosion regions of China”,aims to address the urgent needs of China′s national strategy and scientific developments of soil and water conservation.Taking the 4water erosion regions of northeast black soil,northwest loess,South China red soil and southwest purple soil as the main study areas,the research has concentrated on soil erosion process,modeling and control mechanisms.After more than 4years research,the following have been achieved:revealing soil erosion development processes and spatial patterns,factors and mechanisms of different types at different scales;developing a Chinese multi-scale soil erosion prediction modeling system;developing methods of evaluation for impacts of soil erosion/conservation on environment,and integrating soil erosion control models to fit into the natural ecology and social economy in different regions.All of these achievements have enriched and developed soil and water conservation science,and provide a theoretical basis for the national soil and water conservation strategy and planning in China.

Abstract:The accumulation amount of litter,litter carbon and nitrogen contents,soil available nutrients contents, soil organic carbon content(SOC),and soil soluble carbon(DOC)content were studied in 1m ×1m (tree 20m×20m)plots of grasslands and plantations in Guizhou karst areas.The results indicate that the litter accumulation amounts under the plantations of E.ulmoides,R.pseudoacaciat,P.salicina,A.cremastogyne, and C.duclouxiana were 5.29,3.32,4.26,9.68,and 1.81t/hm2;respectively,which were 1.12to 5.98times of that of the natural grassland.The C:N ratios of the litters increased from 12.84to 57.68after vegetation restoration.The litter accumulation amount correlated significantly positively with the soil rapidly-available potassium contents,rather than the soil hydrolysis nitrogen and effective phosphorus contents.Compared with natural grassland(SOC 7.28g/kg),the organic carbon content of the soils under E.ulmoides,R.pseudoacaciat,P.salicina,A.cremastogyne,C.duclouxianaincreased by 5.24,12.14, 6.04,8.93,and 6.78times respectively.The soil organic carbon content showed no significant relationship with litter amount.However,the relationship between the accumulation amounts of litter and the soluble carbon contents was significant linear in 0—10cm soil layers,but not in the layers below.

Abstract:Soil samples from four land use types including forest,shrub,cultivated land and orchard were collected to investigate the soil organic carbon(SOC)storage,decomposition rates and the accumulation rate of degraded SOC in the karst area of Maocun village,Guilin City.The results show that the contents of SOC varied under different land use.The SOC contents of different land use in descending orders are forest, shrub,cultivated land,and orchard for 0—20cm soil layer,forest,cultivated land,shrub,and orchard for 20—40cm soil layer,and cultivated land,shrub,and orchard for 40—60cm soil layer,respectively.The results of the comparative incubation experiment show that the SOC decomposition and accumulation rates in descending order were forest,shrub,cultivated land,and orchard.

Abstract:The positive response of Populus euphraticato the change of groundwater level was analyzed by monitoring different ecological parameters of P.euphraticaon the three typical transects along the lower reaches of Tarim River.The results show that the growth of P.euphraticariparian forests correlated closely with the groundwater depth.The groundwater has been recharged and risen significantly after ten times of water diversion, and also the vitality of P.euphraticaimproved to different extent as the result of groundwaterrecharging. P.euphraticadrought-stress intensified with the rising of groundwater depth.As a result,the response of P.euphraticato ecological water diversion decreased gradually away from the river channel,and along the river,this response reduced gradually from the upper section to the lower section.Although P. euphraticaseedlings have appeared sporadically in the wet area near the two sides of riverbank,the present water-recharging scheme is difficult to realize the reproduction and renewal of P.euphraticain large areas.

Abstract:As sheet erosion has spatial variations along slope,it is important for the improvement of soil erosion theory to explain soil erosion process on different segments of a hillslope.Sheet erosion characteristics on downslope were analyzed based on experiments of simulated rainfall with multiple plots.The results show that the sheet erosion characteristics on the down slopes differed from those on the whole slopes and upslopes.The sheet erosion on downslopes displayed extremely strong variability.The sheet erosion rates fluctuated with rainfall course,rainfall intensity,and slope gradient.Generally,it increased with the increased time at beginning and then stabilized.The rate increased with slope gradient and rainfall intensity.The variation of sheet erosion modulus with rainfall intensity and slope gradient can be described by a duality linear equation and rainfall intensity affected sheet erosion modulus much greater than slope gradient.The impact of runoff from both upslope and downslope and sediment from upslope on downslope sheet erosion were described by a duality linear equation,with contributions of 56.9%and 25.4%,respectively.Runoff had a greater effect than sediment.It can effectively control sheet erosion on downslope to take measures such as increasing the infiltration and reducing runoff

Abstract:Qiaogou watershed,located in the hilly-gullied loess region,was chosen as the study area.Based on the observed data from the natural runoff plots and hydrological stations built on different landscape positions, the temporal and spatial characteristics of sediment delivery ratios(SDR)under single rainfall events were discussed.The dominant factors affecting the SDR were determined by correlation analysis.The results show that the antecedent soil moisture content,rainfall characteristics,runoff erosivity power and sediment relative bulk density were the main factors controlling the SDR in this area.Using these dominant elements, a sediment delivery ratio formula was built by nonlinear regression analysis.

Abstract:The Holocene palaeoflood slackwater deposit(SWD)was found in the lower reaches of the Weihe river by field investigations.Sedimentary samples were taken after detailed observations and pedo-stratigraphic subdivisions. Grain-size distribution,magnetic susceptibility,loss-on-ignition and CaCO3content were measured in the laboratory.The results show that these bedded palaeoflood slackwater deposits are silty clay,very dense and hard,with blocky structure and low magnetic susceptibility,which are very different from the aeolian loess and soils overlying on the river terraces.Optically stimulated luminescence(OSL)dating shows that these palaeoflood events occurred between 3200and 3000aB.P.,exactly the same time as that documented in the upper reaches of the Weihe river.This time was the ending of the mid-Holocene climatic optimum, and also the ending of the Shang Dynasty in Chinese history.These palaeofloods are closely related with the global climatic decline at about 3100aB.P.The results are of great significance in understanding the response of hydro-climatic system to global change

Abstract:A field study was conducted in Jinyun Mountain Nature Reserve,Chongqing City from July to December in 2010.A LI-8100soil carbon flux measurement system(LI—COR)was employed to measure soil respiration rates(SRRs)in bamboo,mixed wood and coniferous forests.In addition,soil temperature and volumetric water contents were measured at 5cm below ground.By analyzing temporal change characteristic of SRR and its relationship with soil temperature,moisture and litter,the results indicate that no obvious diurnal variation of SRR was found in all the three forests.SRRs during day time were greater than those at night.SRR changed significantly monthly:it gradually increased from July to August and decreased from August to December.The average SSRs during experiment period in the three forests exhibited a decreasing order as bamboo>mixed wood>coniferous.The SRRs of the three forests were closely correlated with soil temperature(p<0.01),with Q10values(the ratio of soil respiration change whenever the temperature increase 10℃)2.67,2.19and 2.13respectively.Conversely,the SRRs were not significantly correlated with soil water contents.In addition,the SRRs of all forests without litter cover were smaller than those with litter, indicated by the greater Q10values found in the forests without litter.

Abstract:Based on sample collection,field monitoring,and indoor experiments,the effects of different types of Grain-for-Green on soil quality were investigated in Huangshui drainage area of Qinghai Province.The results of sample analysis indicate the forests with the same age(8a)in the order of decreasing soil organic matters,total porosity,and total amount of microorganism as:mixture of Picea crassifoliaand birch>birch >mixture of Picea crassifolia and Hippophae rhamnoides>Picea crassifolia>Hippophae rhamnoides> farmland;in order of decreasing soil bulk density and pH value as:mixture of picea crassifolia and birch> birch>mixture of Picea crassifolia and Hippophae rhamnoides>Picea crassifolia>Hippophae rhamnoides> farmland;in the order of decreasing water holding capacity as:mixture of Picea crassifolia and birch>Hippophae rhamnoides>birch>Picea crassifolia>farmland;in the order of decreasing erosion resistance( K)as:Hippophae rhamnoides>mixture of Picea crassifolia and birch>mixture of Picea crassifolia and Hippophae rhamnoides>birch>Picea crassifolia>farmland;and in the order of decreasing heat capacity as:mixture of Picea crassifoliaand birch>birch>mixture of Picea crassifoliaand Hippophae rhamnoides> Hippophae rhamnoides>Picea crassifolia>farmland.The results also show soil microorganisms in the order of decreasing total amount as:bacteria>actinomycetes>epiphyte.Specifically,bacteria accounted for over 95percent of the total microorganism.

Abstract:Based on field experiments with randomized complete block design in a semi-arid location in Gansu Province,the study examined the effects of the timing and amount of supplementary irrigation on potato yield and water use efficiency(WUE).The result shows that supplementary irrigation at the growth stages had significant impacts on potato yield and WUE.Potato yield and WUE in supplementary irrigation treatments were all higher than those of the controls.The highest yield and WUE achieved in the experiments were 19 178.57kg/hm2,which is 21.77%than that of the control,and 52.7kg/(hm2·mm),respectively.Compared with the traditional way,supplementary irrigation improved significantly the yield characteristics: higher percentage medium and large tubers,more tuber number per plant,and higher yield per plant.In addition, the results also indicate that budding stage was the most sensitive time of the potato responding to supplementary irrigation,and the optimal supplementary irrigation amount was 3kg per plant at the budding time.This would be a better cropping management considering both water-saving and high yielding for potato cultivation in semiarid areas.

Abstract:Field plot trials with amaranth,brassica chinensis,and eggplant involving 6different fertilization schemes including non-fertilizer,chemical fertilizer,optimal fertilizer(combined chemical fertilizer and organic manure),organic manure,increased N fertilizer,increased P fertilizer,were conducted under natural rain-fed condition to investigate the effects of the fertilization schemes on yield,as well as N accumulation, nitrogen fertilizer utilization rate,and loss of N by surface runoff.The results show that compared with nonfertilizer, the other 5fertilization models can increased yield of 93.55%,103.74%,96.68%,130.78%and 136.04%,respectively.With different fertilization,the loss of total N by surface runoff varied between 68.11~92.10kg/hm2.Compared with the chemical fertilization,organic fertilization and optimum fertilization could decreased total N loss by 4.67%and 2.02%respectively.Compared with the optimal fertilizer, increasing N and P fertilizer could increase the amount of total N loss respectively by 10.53%and 8.28%. Therefore,the fertilizer ratio should be improved to effectively reduce nitrogen loss on vegetable lands.With steady inputs of N and P,organic fertilizer should be increased while chemical fertilizer should be reduced.

Abstract:Four soil samples were collected from Huajiang distract to represent four different types of land management,including in forest,abandoned land,cultivated land and Zanthoxylum bungeanumforest.Soil aggregates were obtained with dry sieving method for soil enzyme activity analysis.The results show that in the forest,the large soil aggregates(>5 mm)had the strongest soil enzyme activity,and the microaggregates(< 0.25mm)had the lowest.The aggregates from the abandoned land showed an opposite trend, and the aggregates the farmland and Zanthoxylum bungeanum forest were the intermediate.The sucrose, amylase,urease,protease,and phosphatase of the aggregates of all the three sizes showed the highest activity in the forest,and the lowest in the cultivated land.The catalase activity of the aggregates from the abandoned land sample was the lowest.The amylase activity of micro-aggregates(<0.25mm)was the highest. The aggregates showed the order of decreasing amylase,protease,acid phosphatase,and catalase activities as:micro-aggergats>2~1mm aggregates>large aggregats.With increase of aggregate size,the enzyme activity decreased.The aggregates also showed the order of decreasing polyphenol oxidase and urease activities as:micro-aggregats>large aggregats>2~1mm aggregates.The enzyme activity of soil micro-aggregates of was the highest.The forest had the least content of micro-aggregate.The results indicate that the soil enzyme activity in the forest was relatively low,resulting a slow release rate of available nutrients.On the contrary, the nutrients in the cultivated land were released quickly.

Abstract:Soil samples collected from continuous croplands with 2,7,11,15and 20year gravel-sand mulching in Gaolan Research Station,Gansu Province were analyzed for soil microbial population and soil enzyme activities. The results show that with increase of mulching time,soil microbial population decreased from the beginning to a low stable state in about 7to 11years,and then the Shannon diversity index and Mclntosh diversity index continued to decrease.The enzyme activities of soils showed a parabola curve over time.Most of them increased and reached their peaks in 10to 11years,and then declined.The soil enzyme activity of the cropland covered for more than 15years was so low that the yield of the crops decreased.At this stage, farming practices should be stopped,and compost should be added with renewal of soil sand to recover the productivity of the land.The results of the study can provide a theoretical basis for the sustainable utilization and management of the gravel-sand mulched croplands.

Abstract:The major goal of this study is to develop reasonable operation and management practices of Robinia pswudoacacia plantation and improve its stability.Different interfering measures,including Robinia with Caragana,Robinia with pine and Robinia with Forsythia,and Robiniapure forest were investigated through field survey and labortory analysis to analysis and compare the physical and chemical properties,the growth status,and understory species diversity of artificial pure and mixed Robinia.The result showed that different management methods have low influence on population density for the both mixed and pure Robinia;the density of Robinaremained 1 000~1 500plant/hm2 through self-propagation and repair.However,the volume of the pure forest was significant higher than the mixed forests.The stem diameter of pure forest ranged from 8cm to 16cm,accounting for 79.31%of Robiniain sample plot,while stem diameter of the mixed varied from 2cm to 12cm for 82.58%of the Robinia.The coefficient of correlation between diameter and the projection area of Robinia was 0.385in pure forest,and 0.735in the mixed forests.The structure and tree shape of mixed forests was better than that of the pure forest.The pure forest showed less effectiveness inimproving soil bulk density and organic matter than the mixed forests;specifically,the Robinia and Caragana mixed forest exhibited the highest effectiveness.Soil organic matter contents of the pure and mixed forests in 0to 5cm soil layer were 15.50g/kg and 15.19g/kg,respectively.The average organic matter in 5cm to 60 cm soil layer under the mixed forest was 70.6% higher than that under the pure forest.Diversity index of understory herb layer in pure forest was higher than the mixed,however,the richness and evenness index were lower

Abstract:Drinking water in rural areas mainly comes from the local untreated groundwater in northwest Lantian County,Shanaxi Province.The objective of this preliminary research was to investigate the spatiotemporal variation and distribution of nitrate content in drinking well water using geostatistical analysis method on the basis of nitrate content measurements.The results indicate that on the nitrate contents of groundwater varied substantially over different areas and different times and exhibited clear trend effect. Furthermore,the nitrate contents in the water decreased with the well depth.Serious nitrate contamination was found in the water collected from 0—40mdeep well,particularly in the water collected from wells of 0— 20mdepth.The spatial analysis results show that the wells with higher nitrate concentration mainly distributed in the upstream of the river valley and a portion of highlands in the south.

Abstract:In order to obtain the difference of vegetation growth on sand dunes under the influences of paved sandbag barrier and straw barrier,vegetation species number,average vegetation density,height and vegetation coverage of sand dunes in Ulan Buh desert were investigated for three continuous years by quadrat investigation method on dunes protected by sandbag and straw barriers and bare dunes.The specifications,setting location and setting time of the barriers were studied at the same time.The study results show that the longer setting time of the sandbag and straw sand barrier led to better vegetation growth status.With the increase of the setting time, vegetation species number and average height of the two sand barriers remained similar,but their average vegetation density and coverage increased;the average vegetation density reached above 35%,and the vegetation coverage achieved 36.8%and 33.0%,respectively.The positive effects of sand barriers on vegetation increased with the sizes of the barriers:3m×3mwas best,followed by 2m×2mand 1m×1m.The setting locations of sand barriers also mattered regarding the vegetation growth:the best setting location was bottom lee slope,followed by windward slope,middle lee slope location,and top slope.The two types of sand barriers studied showed no difference of the effects on the vegetation growth according to the analysis of variance(p=0.14),however,the two sand barriers were significantly better than the control(p<0.005).

Abstract:Variously aged Leucaena leucocephalain debris flow area of Jiangjia gully were chosen and the fine root systems were dug out from the surface to the bottom layers at different distances from the stem in three directions.Basing on the analysis of fine root vertical distributions and composition,the effect of fine roots on the soil shear strength were estimated according to reinforcement theory.The result show that fine roots exhibited an obvious accumulation trait in the topsoil layer,which reduced with depth.Approximately 80% of the fine root materials were found in the layer between 0—120cm depths.Fine roots were mainly composed of smaller ones(D≤1mm)and determined the development of root distribution.The 10-year stands had more fine roots(D≤1mm)than 5-year ones,and the 15-year stands had obviously more intermediate roots(1mm≤D≤2mm)comparing to the 10-year stands.Root tensile strength decreased significantly with increasing diameter,following apower law function.The soil shear strength enhanced by fine roots was highly variable among depths and ages,largely depended on the smaller roots(D≤1mm).

Abstract:To probe the features of the ecosystem in degraded lands,the research was implemented with pot culture method to understand the coupling responses between the plants and degraded soil under Cu stress. The results show that Cu affected substantially the growth of the tested plants in soils rich in Cu.Under Cu stress,Amorpha fruticosa L.and Pueraria lobataevolved into the dominant species,and the growth of Catalpa bungei,Quercus acutissima Carruth.and CatalpaovataG.Don were restricted and limited to a certain area,but Sedum lineare Thunb and Festuca arundinacea were eliminated in the end.The Cu-resistant plants partially affected the properties of the soil used for pot culture during the period of growth:organic matter content and dehydrogenase activity of tested soil were improved significantly,pH value and total Kjeldahl Nitrogen content remained stable,while P,K and Cu concentrations decreased to some extent.It was concluded that the plants interacted asymmetrically with soil in the ecosystem.For instance,the soil affects obviously the growth of plant merely by one of its limiting factors,whereas the plant influences multiple variables of the soil in the growth process.

Abstract:Based on the monitoring data of soil and water loss in typical small watersheds and the demonstration areas of Zhangjiakou City,the integrated management mode of soil and water loss and its potential benefits were studied in different erosion zones.The results show that for the reconstruction of land use and the selection of engineering and biological measures,the underlying differences between shady and sunny slopes should be accounted for the hilly and rocky mountainous areas,the thickness of the soils in different locations of small watersheds should be considered in the mountainous area,and in the cretaceous terrain area,minimization of the disturbances and breakdown of original ground surface should have the highest priority.Both the typical small watersheds and the demonstration areas which already conducted comprehensive management obtained considerable amount of ecological benefits,the benefits of sediment trapping and water storage reached as high as 70%and 60%for the small watersheds,and both over 60%in the demonstration areas, respectively.At the same time,the vegetation cover percentage and land use ratio increased significantly,resulting in improved capability to control soil erosion.

Abstract:Yield,quality,and water use efficiency(WUE)of Gentiana straminea Maxim were compared in five cultivation modes including white film covered row side planting,black film covered row side planting, white film covered flat planting,black film covered flat planting,bare surface planting in Gannan Plateau, with single factor randomized block design.The results show than black film covered row side planting achieved the highest yield,the most superior quality,and the highest WUE.Specifically,the yield and the WUE of economic yield and biological yield were 39.52%,59.53%,and 21.16% higher than the control, respectively.In short,the black film covered row side planting was the best production cultivation mode of Gentiana straminea Maxim,and should be promoted to a greater extent

Abstract:Based on the analysis of current status of land use in China and the research findings on land retirement from abroad,the authors suggested that land retirement could be an alternative practice for future cultivated land protection in China.Land retirement as a part of sustainable land use,can improve the quality of cultivated land and regional ecological environment,and ensure national long-term food production capacity and food security.Considering the requirement of national food security,a feasible size of land retirement was estimated.An index system consisting of natural environmental quality,utilization intensity of cultivated land and socio-economic development,was constructed to evaluate the regional suitability of land retirement for identify suitable sites for land retirement.Virtual research on land retirement of Tongzhou City of Jiangsu Province was carried out under different development scenarios.The results show that the practicable size of land retirement in Tongzhou City ranged from 661hm2 to 6 410hm2 under different development scenarios. The land retirement areas were mainly distributed in Shigang Town,Qi′an Town and Chuanjiang Town,etc.The virtual research provides a useful reference for the future land retirement policy making in China.

Abstract:Comprehensive assessment of eco-environmental water requirement in arid inland river basins is a multilayer and multi-objective subject for decision-making.At the same time,it is one of key scientific problems to be solved in the reasonable allocation and management of water resources and eco-environmental protection and construction in arid regions.According to the real conditions and environmental problems confronted in the Tailan river basin,an indicator system composed of three hierarchies with 38factors was established to assess the eco-environmental water requirement.The indicators were quantified by classification, and the weights of all factors were calculated by the method of analytic hierarchy process(AHP).Criterion and specific methods were proposed to judge the status of eco-environmental water requirement in the basin. The assessment results indicate that for eco-environmental water requirement,the water resource factor was the dominant ones,the natural factors were the least ones;and the economic-social and eco-environmental factors were the intermediate ones.These four types of factors interrelated with each other,which in combination determine the eco-environmental water requirement.The assessment results agreed well with the reality, which suggests this method is of application value

Abstract:The land ecological security status and trends of Fujian Province from 2000to 2008were evaluated using the quantitative catastrophe progression method(CPM).The CPM avoids the subjectivity in traditional weighting evaluation methods and has less uncertainty in making the standard of security.The results show that the land ecological security of the province was improved gradually from acceptably secure(Ⅲ)to fairly secure(Ⅳ).The increasing security was mainly based on the improving socioeconomic system and environmental control system,while the natural environment system was still fluctuating around acceptably secure(Ⅲ).Specifically,the security of the environment stress subsystem decreased rapidly from 2003,and that of the population pressure subsystem experienced ups and downs.The land ecological security is not optimistic in the future.

Abstract:The results of systematic analysis on the supply-demand situation and the trend of recent years′water resources of Huairou District,Bejing City show that before the water from the south to north water diversion project reaches Beijing City,the water demand in Huairou district is much larger than the supply.Water resources are in a severe shortage situation.The main focus of water resource protection should be water saving.The construction of efficient pipelines,promotion of household water-saving appliances,adjustment of agricultural cultivation structure, and improvement on the recycling rate of industrial water should be carried out with the highest priority.After water from the project reaches Beijing,water demand from Beijing will declined sharply,and the water shortage in this District will be effectively alleviated.The main focus should be the protection and management of water resources; construction and management of sewage treatment facilities,construction of ecologically clean watersheds, and restoration of ground water resources should be carried out until then.

Abstract:As the pollution to farmland ecological environment has attracted more and more attentions from the society,this paper investigated farmers′willingness to protect farmland ecological environment and analyzed the relevant factors in suburban and exurban areas of Wuhan City.Based on proposed theoretical assumptions, the Logistic duality regression technique was used to examine the influential factors of the farmers′ willingness.The results show that the families of the farmers who exhibited strong willingness to protect farmland ecological environment were characterized by more female family members,high proportion of family income coming from agricultural production,fewer family members,possessing high quality farmlands with complete irrigation facilities and good location,concerned about the environment,having the concept that the application of fertilizer and pesticide is harmful to the environment,willing to improve the environment, and so on.In the case with no application of fertilizer and pesticide,farmers′gender composition,the ratio of family agricultural income and environmental satisfaction correlated significantly positively with the farmers′willingness,while their family size,irrigation conditions,land location and recognition of fertilizer′s damage to the environment showed significantly negative effects on the famers′willingness.Recommendations have also been made in this study to promote the farmer′s participation in protecting farmland ecological environment.

Abstract:Expressway from Xi′an City to Hanzhong City(Xihan Expressway)is an important part of the national freeway network.As a pivotal part of the spider-net shaped provincial transport framework,it connects the northern and southern mountainous areas of Qinling Mountains.The road serves also as an essential corridor facilitating West China.The Huxian—Mianxian section of the expressway perforated through the major mountains of Qinling,where the complex topography is characterized with tall mountains and deep valleys.As a result,the construction of the section has to follow strict engineering standards with high technical requirements,owing to the excessive needs of bridges and tunnels.This study discussed the approaches applied to conserve soils during the construction, their effects,and the experiences obtained in some successful cases.The existing issues were also analysed and summarized for the construction and the followed mitigation of the spoil disposal areas.Last but not least,some suggestions and preventative measures were made for future expressway construction.

Abstract:Two giant debris flows occurred in Bayi gully in Dujiangyan County,respectively on August 13and 18,2010,affecting seriously local people’s daily production and life.Based on field investigation data obtained from Bayi gully,the causes and the dynamic characteristics of the debris flows was analyzed,and a detailed risk assessment were carried out.The study results show that the loose material source,rainfall amount and topographic conditions of Bayi gully were contributed to the initialization of debris flows.The debris flows in Bayi gully were giant in magnitude and high in risk.The study provides a reliable basis for the debris flow prevention and mitigation in Bayi gully.

Abstract:Water is the key factor for stable yield and improvement of the agricultural ecosystem in Mu Us sandland.This study investigated the spatiotemporal patterns of soil water variations.The results show that the ways by which soil water escapes increased when the ground was covered by vegetation,especially,the vegetation transpiration influenced soil water substantially through gradual loss.The bare ground showed opposite results.Along with the thickening of dry sand layer,its protection on soil water from loss became more and more visible,and the soil water in deep layers recovered considerably in the latter stage.Considering the protection by the dry sand layer,soil water consumption of vegetation covered land was higher than that of bare field.Clearly,the invalid evaporation on bare surface could not be neglected.Therefore,to recover the agricultural production and vegetation on land of desertificated regions,the ground surface should be covered for reserving soil water as potential water supply.In addition,the understanding of soil water movement in sand field can provide theory evidences for efficient water usage and management for agricultural production in similar fragile regions

Abstract:Based on the three sets of LUCC data(1985,1995and 2000)from the Environmental and Ecological Scientific Data Center of West China,spatial analysis with GIS and statistics methods were applied to analyze the quantitative change,transferring status,and transferring rate of land use types in Danjiang and Hanjiang river.The spatial distributions and the dynamic changes of land use were also studied in regard to different slopes.The results indicate that cultivated land,forest and grassland were the main land use types in the study area,accounting for more than 99%of the total area.From 1985to 2000,the areas of cultivated land,forest,architecture and water deceased and then increased,as the grass land showed the opposite trend.Cultivated land and architecture land increased 105.08km2 and 14.85km2 respectively,forest and grass land decreased 41.02km2 and 77.63km2 respectively during the fifteen years.In terms of slopes,the land use change mainly occurred on the lands with slopes from 5°to 35°,and the land with slope from 15°to 25°experienced the greatest change

Abstract:The definition is the foundation of the assessment of intensive use of cultivated lands.The study developed an indicator system for cultivated land intensive use in Heilongjiang Province.With calculations of entropy and composite index and support of GIS,this study analyzed the spatial difference in intensive usage of the cultivated land.The result shows that,the intensive use level of the cultivated lands displayed obvious regional differentiation characteristics,influenced by the natural conditions of the regions.The cultivated lands in the middle and south parts of the study area had the highest intensive degree,those in the east and west were lower,and those in the north were the lowest.In terms of the weights of the indicators,the investment intensity was most important factor in evaluating intensive use of cultivated land.The farming infrastructure investments in the study area were substantially lower than the production investment.The findings of the project provide the basis for policy making and adjustment of farming investment in the area.

Abstract:Great changes have been taken place in the basin of Heihe river after 10-year allocation of water and ecological restoration,which needs overall and scientific evaluation for future related policy making.The results of our investigation indicate that the agricultural water usage increased substantially because of ineffective farming structure.The promotion of the water-saving irrigation was restricted as lack of financial support in comparison of low water price.There were high risks to keep the current achievement through the previous ecological restoration.Much of the restored vegetation was at risk of being converted once again into farmland and rangeland when the project′s living subsidies ended,which will severely undermine the environmental sustainability achieved through the project.Poverty alleviation would be the key factor to sustain the ecological achievement.Based on these findings,we concluded that successful environmental restoration projects must include both education and economic development components

Abstract:The land use status of Lanzhou City was investigated,and an evaluating indicator system was constructed by combining the economic development and the land use characteristics of the city.The C2 R model and data envelopment analysis(DEA)approach were used to quantitatively analyze and evaluate land utilization economic benefit of the city from 1997to 2008.The results show that the land utilization of Lanzhou City had high economic benefit level.However,in non-DEA efficient years,the land input was sufficient while the land output was not.Lastly,four suggestions were proposed to improve the economic benefit,including promoting intensive land use,improving low efficiency land,adjusting the industrial structure and paying more attention to the coordination of man-nature relationship.

Abstract:The three-parallel-river area is referred to as the parallel drainage basins of Nujiang,Lancang and Jinsha rivers,where debris flows occur frequently.Based on analyzing the characteristics of debris flow disasters occurred in this area,five indexes including slope,lithology,fracture,vegetation and human activity, were chosen as the evaluation indices of debris flow hazards.Supported by ArcGIS,databases of debris flow hazard assessment,graphics and attribute tables were established.The study developed models for risk assessment and obtained the hazard zonation map of the area by normalizing,classification and weighting the evaluation factors.The results agreed well with the actual debris flow events and can provide an important basis for identification the potential disaster targets,optimization of disaster prevention measures and disaster reduction policy making

Abstract:Ecological benefits of the three-north shelter forest project were evaluated based on total value calculated from the data regarding project status,which was estimated using remote sensing monitoring and ground truthing in Zhongyang County,Shanxi Province.An ecological benefit evaluation map of the threenorth shelter forest project was acquired using GIS,providing a basis for project evaluation and ecological compensation.The results show that the three-north shelter forest project in Zhongyang County has improved ecological environment significantly,resulted in annual average ecological benefit per unit area of 40 807.05yuan/(hm2·a),and annual total ecological benefit of 3.08×109 yuan/a.As of the spatial distribution, the sites located in the earthy-rocky mountainous area developed a large number of natural secondary forests,suggesting a better environmental conditions than in the loess area.Annual average ecological benefits per unit area in the earthy-rocky mountainous and in loess area were 42 800.98and 37 342.20yuan/(hm2 ·a),respectively.In terms of vegetation type,annual average ecological benefit per unit area of the forests (coniferous,broadleaved,and coniferous and broadleaved mixed)was greater than that of shrub,as of 44 618.59and 37 414.95yuan/(hm2·a),respectively

Abstract:A study on the pH value,organic matter and magnetic susceptibility of urban soil in different function zones was conducted systematically in Fuzhou City.The result shows that the pH of the soils ranged from neutral to alkaline,which may be contributed by the discharge of alkaline waste during the urbanization process.The contents of soil organic matter were high generally;the industrial zone,commercial zone,scenic zone and cultural zone had high to low organic matter content,respectively,reflecting the direct relationship between soil organic matter content and human activities.The overall high magnetic susceptibility values indicated that the soils in Fuzhou City subject to substantial heavy metal pollution.The magnetic susceptibility of the function zones in order is industrial zone>commercial zone≥cultural zone>scenic zone.There is no correlation between the three variables,which is significantly different from the physiochemical properties of natural soils.

Abstract:The Toona sinensis plantation in Zhenning County of Guizhou Province were classified according to the age as class I(8~13a),classⅡ(15~25a)and classⅢ(>25a).Indicators such as the content of soil organic matter,particle size composition,content of dry soil aggregates(>0.25mm),content of waterstable aggregates,and soil structure destruction rate were determined for erosion resistance evaluation of the soils under the plantations.The results show that,the average contents of soil organic matter were 4.56%, 5.02%and 5.35%,the contents of dry soil aggregates(>0.25mm)were 92.19%,96.72%and 98.07%, and the contents of water-stable aggregates were 65.83%,70.72% and 75.29%in class I,classⅡ,and classⅢ,respectively.Correlation analysis showed that the contents of soil organic matter and water-stable aggregate,and structure destruction rate were the best indicators for evaluating soil resistance to erosion. The erosion resistance of soil was influenced by forest age significantly according to variance analysis;soils from older forests showed stronger resistance to erosion.As expected,soil erosion resistance in Toona sinensis plantation was stronger than that in non-forest lands.

Abstract:The relationship among the controlling factors of reservoir slope stability are highly non-linear. Meanwhile,the adaptive neuro—fuzzy inference system(ANFIS)has been widely recognized for its capability of nonlinear dynamic analysis and processing both certain and uncertain information at the same time.Hence, the employment of ANFIS to assess the stability of reservoir slope was proposed.With eight parameters including permeability coefficient,declining rate of the water level,pore pressure ratio,slope angle,slope height,cohesion,internal friction angle,and severity as the inputs,and the reservoir slope stability coefficient as the output,a ANFIS model has been constructed based on 21project cases.The training correlation coefficient of the model was 0.999 96,and the correlation coefficient of the validation was 0.977 48,which was significantly better than the BP neural network model.The successful prediction on the slope stability of a dam reservoir in Jiangxi Province illustrated a desirable forecasting ability of the established ANFIS model for coupling multiple impact factors

Abstract:In order to study the chatacteristics of different soil erosion and sediment yield indoor and outdoor under rainfall condition,the erosion processes of Mangshan mountain loess were tested under laboratory and undisturbed conditions on 25°steep slopes under artificial simulated rainfalls.The similarity characteristics of the indoor and outdoor process of erosion and sediment yield were analyzed by the fuzzy closeness degree calculation method.The results show that with the rains of same intensity,runoff amount,sediment concentration, shear stress,and sediment yield of different soil bulk densities were fairly low at the initial stage and increased gradually over time;when the rain intensity reached the hyperplastic spot,these indicators increased sharply to the steady state within a few minutes.On 25°steep slopes,the nearness degree of the shear strength,runoff rate,sediment concentration and sediment yield of both indoor and outdoor simulation were very similar for the two kinds of soil bulk densities.The nearness degree of the high bulk density(1.2 g/cm3)soil was greater than the low bulk density(1.0g/cm3)soil.This implies that in order to achieve a laboratory condition similar to the field condition,the soil with higher bulk density should be applied in the simulations.

Abstract:The spatial distribution patterns of direct solar radiation were investigated in Jieba mountain based on the function of solar radiation calculation in ViewGIS.The purpose of this study is to provide preliminary data and scientific evidences for regional planning and environmental construction.The results of spatiotemporal distribution analysis show that the direct radiation increased with the elevation.Greater amount of radiation were found at plantation and less at lower parts of the hills.The calculated radiations were found in descending order at the locations of plantation,flood land,summit,middle and upper part of hill,gully,and lower part of hill.On the other hand,direct radiation decreased with the increase of slope degree.The direct radiation also varied with slope aspects;sunny slope,semi-sunny slope,semi-shady slope,and shady slope had direct radiation in descending order.

Abstract:Sewage sludge may be exploited as water retaining agent owing to its characteristics of low water permeability and drying rate,which were considered as the technical barrier of sewage sludge application. Plot and pot culture of corn were conducted in the experiment to study the influences of different content and placement of sewage sludge on water retention.Water content,water loss and water loss rate in plot culture together with soil water content and plant biomass in pot culture were measured and analyzed systematically. The treatment with high sewage sludge amount had a significant effect of water retaining;sewage sludge had a better effect in pot culture and a worse effect in plot culture than the treatment of SAP(super absorbent polymer).Different placement of sewage sludge experiment showed that placing sewage sludge in a sandwich way was better than just mixing with soil.Especially,placing the sludge in two layers was superior.In summary, sewage sludge has a strong ability of water retention,which requires further investigation.

Abstract:The knowledge of vegetation cover changes will provide considerable insights into the dynamic process of desertification.The study illustrated the vegetation dynamic changes in Dulan County,Qinghai Province using 2000—2009MODIS NDVI data,and on this basis,the relationship between NDVI changes with temperature and rainfall variations were investigated,providing the basic data to land use planning in alpine areas and desertification prevention and control.The results indicate that the NDVI values of the area presented a slow ascendant trend from 2000to 2009,at the rate of 0.002 9/a.The NDVI values had a strong seasonal changes in a year,but the overall NDVIs were not high for the county,with the maximum value of 0.22.The vegetation condition were improved significantly in 39.71%of the area of the entire county,which mainly located in basins of Chacha river and Chahanwusu river and a large area of Qaidam river downstream.However,the vegetation degeneration was found in the upper and middle reaches of Qaidam river,accounting for 17.74%of the entire county,suggesting that the desertification control should be further strengthened.The temperature and rainfall were the two main natural factors influencing the NDVI dynamics of the county;the NDVIs correlated strongly significantly with the temperature(p< 0.01),and significantly with the rainfall amount(p<0.05)from May to September annually.The impact of the temperature on the NDVI was stronger than that of the precipitation

Abstract:Based on SPOT-VGT NDVI and meteorological data from 1999to 2009,the paper synthesized monthly and yearly maximum NDVI,and standardized anomaly NDVI.Using some spatiotemporal analysis methods,such as regression analysis,correlation analysis and variation coefficient,the paper studied the dynamic characteristics of vegetation in Ningxia Hui Autonomous Region over recent 11years.The spatial distribution analysis results show that the NDVI values were higher in the north and the south part,but lower in middle.This characteristic agreed with the geographical division and vegetation distribution pattern of Ningxia.The NDVI values changed greatly over time and responded closely to yearly precipitation,especially in the drought zone located in the middle of the region.The NDVI in most places within the region increased during the period and in only five areas decreases of NDVI were found,which indicated the whole vegetation cover the region became better over the period.The spatiotemporal variations of NDVI show that the ecosystem has been gradually improved in recent years as the NDVI variations responded clearly to the ecosystem changes.There had some ecological restorations projects applied recently,which might be the major factor that resulted in the increase of NDVI in the region

Abstract:Land cover change and its response to climatic variations is an essential part of researches on global climate change.Based on SPOT normalized difference vegetation index(NDVI),the land cover changes of the loess plateau during the last ten years were analyzed at multi temporal scales using several geo-statistical methods,as well as the response of NDVI to the precipitation and temperature.The results show that the vegetation cover increased substantially during 1999—2008.All the NDVIs at the scales of 10-day,month and season showed single-peak curves with the maximum in August and the minimum in February.Monthly scale was found the appropriate scale for the study addressing the response of NDVI to precipitation and temperature on the loess plateau.The responses of NDVI to temperature and precipitation varied at different scales on loess plateau.The coefficients of correlations between NDVI with temperature were greater than that with precipitation at 10-day or month scale,while lower at season scale.

Abstract:The temporal and spatial variations of normalized difference vegetation index(NDVI)in Zhangye region during 2000—2008were analyzed using the gravity center of vegetation,linear regression and R/S analysis based on the MODIS—NDVI data.The results show that the gravity center of vegetation moved eastward during 2000—2003,indicating increases of vegetation cover in the east and decreases in the west. The gravity centre of vegetation moved northward during 2006—2008,which revealed the vegetation increases in the north and decreases in the south during this period.Annual variations of the vegetation gravity centre were unstable from January to May and from November to January,but stable from May to November. Vegetation cover increased in basins of Shandan,Minle and Zhangye during recent ten years,which accounts for 75.98%of the whole study area.The main land use types of the study area were dry land and artificial grassland.The artificial vegetation increased faster than natural vegetation.Degraded regions distributed sporadically over Zhangye Basin and Qilian Mountain due to intensified human activities.The Hurst index of the growing season NDVI focused on 0.4~0.6,indicating weak sustainability and/or non-sustainability. However,the indices of each month in the growing seasons differed substantially.The Hurst index showed a transition of vegetation cover from sustainable in May to unsustainable in July,while the sustainability of the vegetation cover increased in August and September.The results also show different land use types in the order of increasing Hurst value as:unused landⅡ

Abstract:Grid width is generally treated as the width of flow path for flow convergence in many traditional distributed hydrologic models.The flow velocity obtained from these models differs substantially from the reality,which may undermine immensely the accuracy of the results in hydrologic modeling,soil erosion simulation and other related studies.A distributed hydrologic model was developed based on Horton infiltration curve and simplified Saint Venant equation in this study.A curve called as flow path width curve was developed to describe the varying of flow path width with upstream contributing area as flow gathering.Some observed data of Dongwan watershed was applied to test the model,and the results proved its superiority in distributed outputs.

Abstract:To study spatio-temporal characteristics of urban heat island effect of Xi′an City,the study inverted brightness temperatures of three time periods based on three Landsat TM/ETM+images of 1990,2002 and 2007,which were then normalized and scaled into six grades to calculate urban-heat-island ratio index (URI).The impacts of vegetation on urban heat island were further discussed through the relationship between NDVI values and urban heat islands.The results show that URI increased and the effects of urban heat island were strengthened in Xi′an City from 1990to 2007.During this period,the urban heat islands evolved from scattered spots to flakes,and then to connected flakes,and the distribution of urban heat island approached from the districts of Lianhu,Xincheng,Yanta,Beilin to the districts of Weiyang and Baqiao. The NDVI values were negatively correlated with urban heat island.Appropriately increasing urban green areas might be able to reduce significantly the urban heat island effect

Abstract:Understanding of precipitation spatial heterogeneity is of great importance in water resource management. The study analyzed spatial heterogeneity of precipitation on Lü′er gully small watersheds of the third subdivision in the hilly—gully region of the loess plateau from a topographic perspective.The results indicate that the average annual precipitation decreased from on the upper to the middle and lower reaches, and increased with the altitudes.Different precipitation intensity resulted in different spatial heterogeneity of precipitation;the more the precipitation,the more the spatial heterogeneity.The equivalent curves were simulated for different precipitation events with SURFER software,which implied that the effects of elevation and distance from the channel mouth increased with the amount of precipitation.

Abstract:Wind velocity,air temperature,air relative humidity,photosynthetically active radiation were synchronously monitored using HOBO Portable-Meteorological Stations in the three nature communities including Tamarix ssp community,Tamarixssp—Alhagi sparsifoli—Karelinia caspicacommunity,Alhagi sparsifoliacommunity in the oasis—desert transitional zone of Qira County between July 23and August 24,2010.The difference of microclimate among the three plant communities was analyzed.The results show that the vegetation in the transitional zone has particular partial climate effect.With increase of vegetation coverage,wind speed and air temperature decreased, and relative humidity increased.The vegetation covers in communities of Tamarixssp,Tamarix ssp—Alhagi sparsifolia—Karelinia caspica,and Alhagi sparsifolia were 3%,27%,and 67%,respectively. During the observation period,the average wind speed at 0.5,1,2,4,8,and 10mhigh in Tamarix ssp—Alhagi sparsifolia—Karelinia caspica community and Alhagi sparsifolia community were 32%and 47%lower than that in Tamarixssp community;specifically,the average wind speed at 0.5mhigh was 57%and 47%lower,respectively.In communities of Tamarixssp—Alhagi sparsifolia—Karelinia caspica and Alhagi sparsifolia,the average air temperature(2mhigh)were 0.32℃and 1.02℃lower,and the average air relative humidity(2mhigh)were 2.33%and 7.67%higher than those of the Tamarixssp community,respectively.However,the photosynthestically active radiation had no significant difference between the three communities, although it was 40%and 60%lower on cloudy days and dust storms than that on clear days,respectively

Abstract:Water pollution is one of the most serious environmental problems in China,and its control has become the urgent task for our environmental conservationists.In order to improve the ecological environment of the northwest of China,it is of great importance to study and protect the lakes in the area.The Sand Lake of Ningxia Hui Autonomous Region was chosen as the study object and principal component analysis and fuzzy comprehensive evaluation method were applied to evaluate its water quality variations from 2000to 2009.We found that the water quality was getting better during the study period.Specifically,the fuzzy comprehensive evaluation method illustrated well the water pollution levels and principal component analysis adequately detected the water pollution degrees.The results were more objective with combination of principal component analysis and fuzzy comprehensive evaluation.

Abstract:To explore the dynamic process of soil moisture under different mulching techniques in karst areas, an experimental research of soil moisture dynamic changes was carried out in Huajiang typical karst valley area of Guizhou Province from March to May,2009.The results show that under the controlled condition, the evaporation of soil moisture closely related with the way and area ratio of covering.The magnitude of changes in soil moisture over time was bare land>thin-film semi-covered land>gravel throughout land>litter throughout land>thin-film throughout land.The relationship between soil moisture contents and time was best fitted by third degree polynomial equations.Soil firmness,soil porosity,soil bulk,density,and soil permeability differed significantly under different coverings.Although the water-holding capacity of the soil under thin-film throughout treatment was the highest,its permeability and porosity was fairly low.The soil under the gravel throughout has the highest infiltration rate and firmness

Abstract:The correlation between watershed landscape pattern and water quality depends upon the temporal and spatial scales.The study addressing different spatio-temporal scales could provide a clear basis for integrated management of land and water.Typical sub-watersheds of Nenjiang river were chosen as study sites, and the correlation between landscape pattern and river water quality was studied at the scales of sub-basin and riparian,wet and dry season,then the temporal and spatial difference in correlation was analyzed.The results of spatial scale analysis indicate that,more landscape indices correlated significantly with water quality indices at the sub-basin scale than at the riparian scale.Along with increase of spatial scale,the negative relationship of NO3—N and integrated pollution index with the forest percentage declined after initial increasing, and this negative relationship reached its strongest at the 400mbuffer.While the positive correlation of TDS,NH4—N,NO3—N,integrated pollution index with the farmland percentage also decreased after initial increasing along with increase of spatial scale,and the strongest relationship was found at 300mbuffer. Therefore,300~400m might be the critical area for river corridor management of Nenjiang river.As for temporal scale analysis,more landscape indices correlated closely with water quality indices in wet season than in dry season.In wet periods,forest,grassland and farmland landscapes were more relevant to water quality,while the construction landscape was more relevant to water quality in dry season

Abstract:The soil water characteristic curve and unsaturated hydraulic conductivity gained from seepage tests in Xiajiang reservior area of Jiangxi Province,were fitted by the Van Genuchten(VG)model,and a new multi-component model consisting of plough layer,plough pan,impermeable layer and raising layer was established for the raising-farmland.A three-dimensional saturated-unsaturated mathematical model was also used to simulate the tests based on the parameters of the VG model.The results show that the mathematical model was reasonable and reliable.In addition,the effects of soil compaction and the thickness on the raising- farmland seepage were investigated.A large number of experiments were reduced by the mathematical analysis and the simulated parameters could be used in the engineering design and construction.