Abstract:Allocation of soil organic carbon in physical fractions was measured in mobile sand dune,and stabilized sand dune usingPinus sylvestris var.Mongolica(22year forest land)andCaragana microphylla(24year shrub land)in Horqin sandy land.Results show that(1)the contents of coarse sand,very fine sand andclay+silt,and electric conductivity increased while fine sand content and soil bulk density decre-ased in woodland, compared with mobile sand dune,(2)the whole SOC storage increased by 729% with an increment of 357g/m² in forest land,and by 1050% with an increment 514g/m² in shrub land,(3)dry organic mattersin light fractions account for 0.08%,1.24% and 1.14% of the total soil weights,while carbon storages inlight fractions are 9.7,182.5 and 185.9g/m²,accounting for 20%,45%and 33% of whole SOCs in themobile sand dune,forest land, and shrub land,respectively,(4)the allocations of SOC in particle-size fractions were in orders as fine sand>coarse sand>very fine sand>clay+ silt for the mobile sand dune,coarsesand>fine sand>very fine sand>clay+silt for the forest land,and coarse sand>very fine sand>fine sand> clay+silt for the shrub land,and(5)the variations of light fraction carbon were more sensitive than thewhole SOC after sand dune stabilization.Also,the increase of unprotected organic matter within coarse sandfraction played an important role in the change of whole SOC.

Abstract:Forest litter,which has a high water storage and retention capacity,is an extremely important hydrological component for sustaining water conservation function of the forests.The variations of forest litter containing moisture(FLCM)and forest litter water storage(FLWS)were analyzed in Southern Jiangsu Province,associating with influencing factors such as soil water contents and meteorological parameters.The results show that evergreen broad-leaved,deciduous broad-leaved,pine(pinus taeda L.),and bamboo forests had FLCM values from high to low,respectively,and similarly,deciduous broad-leaved,evergreen broad-leaved,pine,and bamboo forests had high to low FLWS values.Precipita-tion had an obvious impact on FLWS,as well as evaporation.The increase of FLCM resulted from precipitation normally had a time lag of 1 to 5 days.Evaporation correlated negatively with FLCM,with correlation coefficients of -0.39,-0.38,-0.13and-0.32for deciduous broad-leaved, ever-green broad-leaved,pine,and bamboo forests,respectively.FLWSS of deciduous forests(deciduous broad-leaved and bamboo)are affected by soil moisture contents more significantly than those of evergreen forests(pine and evergreen broad-leaved).FLWSS correlated with soil water contents of 10cm more closely than those of 20cm.

Abstract:The eco-hydrological characteristics of natural secondary evergreen broadleaved forest in Miaoshanwu Nature Reserve were studied based on field observations within a time period of one year.The results show that soil moisture of natural secondary forest has significant temporal and spatial variations.The average annual soil moisture content ranged from 14.24%to 22.55%.Similar to precipitation,soil moisture content increased firstly and then decreased during ayear.Soil moisture of the surface layer(0-5cm)exhibited strong variability.With the increase of soil depth,the coefficient of variation of soil water content decreased.Strong variations of monthly slope surface runoff were observed and were found closely correlated with single-event rainfall.In the watershed scale,monthly surface runoff varied in a wide range with a maximum runoff of 389.11mm in August.The results of water quality sampling show that most water quality indices qualified the first level in the governmental standards,except for total N contents and pH values.

Abstract:Forty-nine species of plants,belonging to 15 families and 38genera,were identified in the middle reaches of the Tarim River in Xinjiang Wei Autonomous Region.The floristic constitution,geographical elements of families,genera of seed plants and species diversity were analyzed in this area.The results show that the flora had highly diverse geographical characteristics.Flora dominance was apparent as many single famili-es and single-genera existed.Most of the flora was strongly xeromorphic and antique.The flora dominated by temperate species,indicating that the flora characteristics of the middle reaches of the Tarim River agreed well with that of the North Temperate zone and old Mediterranean Sea.The percentage of endemic species was low,and rare and endangered plants were scarce.According to species diversity index of different habitats with various forest ages,water was the main factor affecting species diversity.

Abstract:Two methods including tillage,sand and soil mulching were applied to reduce surface compaction of dredged sediment.The combining effects of submerged plant restoration and surface covering were tested in terms of controlling the release of the inner-loaded nutritional salts from contaminated lake sediment.The results show that different sand and soil coverage notably reduced nitrogen and phosphate release rates at the beginning of the experiments,but the release rates bounced back after a extended time period.With comparison of the control,the treatment of combining surface covering and plant restoration(growingPotamogeton crispus) significantly retarded release rates of nitrogen and phosphate.However,the treatment of combining tillage and plant restoration provided the superb release rate of inner-loaded nutrients.

Abstract:The water holding capacity was characterized for the litters from eight plantation types in the mountainous area of Napahai Plateau Wetland. The results show that,for all the eight plantation types,the semi-decomposed and decomposed layer had higher litter storage and water reserv-ing capacity than the freshly-littered layer.The litter storage decreased from highwood,shrub to waste grassland.Specifically,the litter storages of naturalPicea asperataMast,mixed forest ofPinus densataMast andRhododendron simsiiPlanch,mixed forest of Salix cupularisRehd andBetula platyphyllaSuk,Crataegus pinnatifidaBge and waste grassland demonstrated a capacity of 36.60, 30.67,26.63,25.61 and 5.30t/hm²,respectively. Comparatively,mixed forest ofSalix cupularisRehd andBetula platyphylla Suk had the highest water holding capacity,and seriously human-disturbedPinus densataMast had the lowest.The water holding capacity of the litters increased rapidly during the initial first hour,and then slightly increased after 6～10 hour saturation.The highest water absorp-tion rates were observed in the first 30minute saturation time,and thereafter the rates decreased substantially.Water loss rates were similar for all the litters,showing a linear decreas-ing trend.Systematic analysis indicated that the litter of mixed forest ofSalix cupularis Rehd andBetula platyphyllaSuk had the highest water holding capacity,the strongest flood-adjusting capacity,the most ideal water loss process and the highest water supply capacity,and the best hydro-ecological effect among the eight plantation types.

Abstract:A complex coupled relationship between grasshopper and vegetation is often recognized.The characteristic change of grasshopper community is an important ecological response to the plant community.In the Baidaban grassland of the upper reaches of Heihe River,sample investigation methods were used to study grasshopper community composition,diversity and its relationship with the plant community from June to August, 2009.Thirteen species of grasshoppers were identified among seven plant communities.The grasshoppers was composed of ten genera of three families,within whichOedaleusdecoratus,Gomphocerus licentiandChorthippus albonemuswere the dominant species in the research area.The highest populations were found in the plant communities dominated byArtemisia dalailamaeorStellera chamaejasme.The community composition and dominant species were significantly different in seven plant communities.However,no significant difference was found for evenness index (p>0.05).Grasshopper community diversity and species richness had positive correlation with vegetation coverage and diversity,but related negatively with plant height and plant dominance index.Meanwhile,grasshopper abundance was high in species-enriched plant communities.Negati-ve relationships were identified between grasshopper Pielou evenness index and plant community diversity,and grasshopper dominance index had positive correlation with plant dominance index.Grasshopper distribution and population were affected by biology characteristics of grasshop-per and plant community composition.Grasshopper choice diversity to plants reflected strong adaption and cooperation function of the grassh-opper population.

Abstract:Analysis on the variability of inflows into the Miyun Reservoir was performed at both Xiahui(Chaohe River) and Zhangjiafen(Baihe River) stations and the relationships between the flow volumes and precipitation and land use change were addressed.Based on inflow variability analysis,daily pulse number and mean pulse duration were statistically discussed for the estimation of various stream flow thresholds.The results show that the inflows decreased and exhibited less temporal variability at both Xiahui and Zhangjiafen stations during 2002-2006, comparing to those in the 1980s.The variability of the stream flows was mainly affected by precipitation.The increase of grassland area might reduce the inflow velocity,and the decrease of forest increased the high threshold volumes and at the same time could reduce total flow volume.However,land use change had only little contribution to stream flow variations,owing to only insignificant change was detecte during this time period.

Abstract:The changes of the vegetation characteristics of alfalfa grasslands under different fertilization schemes were analyzed with the trial of plot experiments.The results indicate that the species richness index of the continuous cropping alfalfa grassland did not significantly change under different fertilizer treatments,along with considerably increased community coverage,and significantly raised community heights. Fertilization could maintain species diversity and community stability and enhance alfalfa grassland productivity.After the application of fertilizer,the niche breadth of alfalfa population significantly increased and the competitiveness strengthened relatively.However,the niche breadth of forbs decreased and relatively weakened.No significant niche overlap was found between alfalfa population and other species under continuous cultivation and fertilization.Greater niche overlap was found among the forbs,between which the competition was more intense and dominant.Fertilization could improve the quality and economic value of alfalfa grasslands,while the invasion of forbs functional groups such asSetaria viridiswas one of the most important factors degrading the grasslands.

Abstract:Under-plastic-mulch drip irrigation was studied through field experiments in arid areas of Xinjiang in 2009.The influences of various irriga-tion quotas and frequencies on water-salt distribution and cotton growth were analyzed.The results show that irrigations with a cycle of 5days achieved the most appropriate moisture condition for cotton growth.With same irrigation quota,soil moisture increased by shortening irrigation cycle time.The higher irrigation frequency effectively reduced the salinity of root area.The treatment of 10 day cycle introduced fluctuations of salinity in soil and resulted in salt accumulation at the growth period.Considering water conservation,yield enhancement and soil salt reduction,the irrigation quota of 3900m³/hm² with a irrigation cycle of five to seven days are desirable for agricultural industry in the study area.

Abstract:Soil water is one of limiting ecological factors for vegetation restoration and succession in arid and semiarid regions.The presence of bio-logical crust on sandy soils limits water infiltration depth and reduces water availability for deep-rooted plants;meanwhile,the biological cover can affect greatly the spatial variability and redistribution of soil water.It is therefore necessary to apply proper disturbance on the crust to promote ecological restoration and rehabilitation.It may also be important to address the influences of biological crust on soil evaporation,which is a major part of soil water loss after natural rainfalls.In this study,soil evaporation features were studied after remo-val disturbance and sand burial disturbance on biological crust in a sandy soil of the Loess Plateau, China, which experiences severe criss-crossing water and wind erosion.The results show that removal of the crust did not effectively reduce soil moisture evaporation compared with control(p>0.05),while sand burial significantly decreased soil evaporation(p<0.01).Soil evaporation was increasingly reduced with the sand bed thickness.The sand burial depth of 20mm had the greatest inhibitive effect on soil evaporation reduction,and the cumulative evaporation was reduced by 58.15%at the end of the experiment.There was no significant difference between 5mm and 10mm sand burial depths (p>0.05),which reduced soil evaporation by 25.20%and 28.29%,respectively.The findings show that sand burial disturbance has positive effects on conserving soil water in the study area .

Abstract:Over a long period of field experiment,soil water conditions were monitored in different woodlands with plants ofTamarix ramosissima, Populus euphratica,Alhagi sparsifoliaandCalligonum caput-medusae.Soil water retention curves from 0cm to 100cm were fitted for farmland and desert soils based on field data.The results show that,soil water contents gradually increased with depth in 0-250cm.During the growing season of September and October,soil water contents in 0-60cm layer were significantly higher than in the other months.Single heavy rainfall supplied a considerable amount of water to the soil layer of 0-60cm,while deeper soils were affected very little.The monthly change of soil water storage capacity was insignificant,fluctuating between120mm and140mm.However,the storage capacity differed in the fourspecies as in order ofP.euphratica>T.ramosissima>C.caput-medusae=A.sparsifolia.The evapotranspiriation ofP.euphratica, C.caput-medusae,T.ramosissimaandA.sparsifoliaduring the growing season ranged from high to low,respectively,as the highest values were observed in June.Exponential relationship between soil water contents and soil water potentials was found in the layer of 0-100cm for each soil,and all the correlation coefficients were over 0.90.The results provide necessary theoretical references for ecological water needs of vegetation recovery in this area.

Abstract:PEG-6000 solutions with different concentrations were used to simulate drought stress.Four treatments were applied:control(CK),light stress (T₁),moderate stress(T₂)and heavy stress(T₃)to investigate the effects of drought stress on photosynthetic pigment and root,stem and leaf growth characteristics ofElaeagnus angustifolia.The results show that root length,plant height,and leaf number of the plants exhibited the effects of increasing stress.In comparison of CK,root length,and plant height of T₂except for leaf numbers were significantly different.In T₃,root length,plant height,leave number,respectively.In T₂,fresh and dry weights of root and stem,except for leaf,indicated influences of draught stress in comparison of CK.Similarly,fresh and dry weights of root, stem,and leaf indicated strongest,moderate and least responses to the stress.Along with the increasing degree of drought stress,the contents of chlorophyll a,contents of chlorophyll b,contents of total chlorophyll,and contents of carotinoid Elaeagnus angustifoliaincreased first and then decreased,however,of the ratios of chlorophyll a/b showed opposite tendency.The response of chlorophyll a to drought stress is more sensitive than chlorophyll b.In comparison of CK,soluble proteins of the roots of T₁were 18.6%higher,but that of T₂and T₃were 13.9% and 29.1% lower,respectively.No significant difference was found between stem soluble proteins of T₁and CK,however,stem soluble protein of T₂and T₃was 17.2%and 41.9% higher than that of CK.T₃is the only treatment which leaf soluble proteins were significantly higher than CK(24.3%).

Abstract:The research objects of this study are the railway slopes which were treated with pressure spraying in the construction of Suiming-Chongqing railway.The variations of soil water of the road-slopes were monitored in different slope positions,various slope aspects during four seas-ons.The results show that soil water content peaked at the upper slope position in October,as high as 18.3%.For the other three seasons, the water contents were significant higher at the foot slope than at the upper and middle slopes.No significant difference of soil water were found among four slope aspects in January and October,while in April and July,soil water contents on shady slopes were significant higher than those on the sunny slopes.Soil water contents peaked in October on all the three slope positions.On all four slope aspects,soil water contents in January and October were significantly higher than those in April and July.Significant relationships were identified between soil moisture contents of different slope positions,slope aspects and seasons,except that soil moisture on foot slopes were affected by season changes only.All relationships were positive except between seasonal variations and slope aspects.Seasonal variations of soil moisture were related closely with slope positions rather than with slope aspects.

Abstract:The relationship between biological diversity and productivity of alpine in regard to community structure wetland was investigated on the inland alpine wetlands of Qinghai Lake based on community survey.The influence of environmental integrity on the relationship was addressed in the area.Species diversity was regressed biomass using the SPSS fit curve function.The results show that(1)species diversity and biomass have a significantly negative correlation at both community and regional scales,and(2)regional factors had little effect on the species div-ersity and productivity in the study area,while maintaining the integrity of the regional environment could improve effectively the relevance between species diversity and productivity.

Abstract:In the alpine region of Loess Plateau,light responses ofS.argenteaandH.rhamnoidesseedlings under different soil moisture con-ditions were analyzed in terms of gas exchange parameters using Li-6400 portable photosynthesis system.The results show that net photo-synth-esis rate(p_n),transpiration rate(T_r)and water use efficiency(WUE)of the two species were both increased with PAR in the beginning.With continued increase of PAR,p_nand WUE ofS.argentea andH.rhamnoidesseedlings declined but T_rstill increased.With increasing soil water contents(SWC),p_n,T_r,Stomatal conductance(G_s)and intercellular CO₂concentration(C_i)of two species were both increased,while WUE increased first and then declined after reaching the maximum under the mild water-stress condition.Under similar soil moistureconditions, light compensation point(LCP)ofS.argenteawas clearly lower than that ofH.rhamnoides,light saturation point(LSP)and efficiency of light energy utilization ofS.argenteawere higher than those ofH.rhamnoides,and the apparent quantum yield(α)in the leaves ofS.argenteawas higher than that ofH.rhamnoides.Compared withH.rhamnoides,S.argenteaexhibited higher photosynth-etic capacity at low PAR.Contrastive analysis indicates thatH.rhamnoidesshowed stronger response to high PAR under the waterstress condition,whileS.argentea had higher utilization capacity of low PAR and WUE.Overall,S.argenteaseedlings displayed higher drought-stressed productivity thanH.rhamnoides seedlings.

Abstract:Baseflow is an important component of river flow,especially in the arid loess hilly and gully region.It accounts for a large proportion of total runoff and provide additional flow supply to the rivers during the dry seasons.Therefore,the research of baseflow characteristics and its impact factors in this area could contribute to more reasonable water regulations and more efficient uses of water resources.In this paper,digital filtering method was used to separate the baseflow of Caijiachuan basin from 2006to 2008.By calculating the baseflow index (BFI),controlling factors including precipitation events,land use,vegetation cover and terrain characteristics of the basin were analyzed.The results show that annual BFI averages ranged from 0.68 to 0.82.BFIs decreased with increase of precipitation.Agricultural land,scrub and plantation had negative effects on the base flow.BFIs had a linear relationship with rainfall amounts(P),river networks densities (D)and river gradients(S).The regression analysis provides a basis to analyze the characteristics of baseflow in ungauged area.

Abstract:In order to provide theoretical evidences for vegetation recovery and soil loss control in the gully region of the loess plateau,surface soil moisture characteristics were analyzed by addressing the influences of precipitation and vegetation cover on soil moisture.The experimental plots of Wangdonggou basin in Changwu County was selected as the study site.The results show that soil moisture contents in the 0-30cm soil layers varied moderately.Soil moisture contents of sunny slope(15°)were lower than half sunny slopes(35°).The variations of soil moisture contents responded to the rainfall closely;the soil moisture contents in the 0-10cm layers approximately synchronized with rainfall,but the agreement between soil moisture content and rainfall variations was poor in the 10-20cm and 20-30cm layers.It was observed that the higher the vegetation coverage,the higher the mean of moisture contents.When the vegetation coverage was over 40%,the trend that soil moisture content decreased with soil depth became more obviously in soil profiles of middle slope and down slope.The soil moisture means gradually increased from the summit to foot slope.Soil moisture contents decreased with depth in the 0-30cm soil layers.

Abstract:Based on the runoff data during the period between 1962and 2008,runoff variations in the Jihe river watershed(1019km²), located in the third sub-region of the Loess Plateau,were characterized using statistical analysis.The results indicate that the runoff presented a evident decreasing trend during the research period,and the runoff in the 1970s,1980s,1990sand 2000saccounted for 62.3%,61.1%,30.2% and 35.2% of the 1960srespectively,with an annual increasing rate of-2.7%and and a variation coefficient of 0.75.It was observed that inter-annual distribution of runoff was greatly unsteady,and the runoff percentages in flood seasons ranged from 50.8%to 95.2% with an average of 76.5%and a monthly variation coefficient of 1.13.According to wet and drought year classification of the runoff,Jihe river watershed has gone since the 1960s through the periods of wet year,average year,sub-wet year and drought year,respectively.The runoff decreased dramatically after 1990,lasting a nine-year period of drought,in coincidence with the large-scaled implementation of soil and water conservation.Thorough descriptions of the response of hydrological factors to land use and cover changes are another requirement for future study in the watershed.

Abstract:In order to provide theoretical basis for evaluations on ecological function rehabilitation and vegetation development,the herbaceous structure and diversity of the artificial forests were analyzed in the hill and gully region of the Western Shanxi Province.In this study, vegetation of various densities,includingRobinia pseudoacacia,Ulmus pumila,Pinus tabulaeformis,Platycladus orientalis ,Pinus tabulaeformis and Robinia pseudoacaciamixed forests,were investigated.Thirty-six herbaceous species,of which most were masculine plants,were identified in the drainage basin.The herbages species differed significantly under various forest plantations.The majority of plant successions under the forest plantations were still in their infant stages.In terms of total number of species and dominant species,the conifer-broadleaf forest exhibited the best biodiversity,followed byPinus tabulaeformisandRobinia pseudoacacia, whereasUlmus pumilaprovided the worst condition for bio-diversification.In addition,conifer-broadleaf forest performed best in regard to species diversity and evenness index, in sequence followed byRobinia pseudoacacia,Pinus tabulaeformis,Ulmus pumila, andPlatycladus orientalis.

Abstract:In order to assess water conservational function of different forests types in Laotudingzi natural reserve,six forest soils were selected to test soil storage capacity and infiltration characteristics.The results indicate that soil bulk density(0-40cm)under these forests ranged from 0.76to 1.71g/cm^{3,non-capillary porosity ranged from 8.15%to 22.07%,capillary porosity ranged from 27.060%to 53.28%,soil porosity conditions of natural secondary forests,such as shrub,Betula ermanii,Spinney,were better thanLarix pricepis-ruprechtii andPinus koraiensis, soil water storage(0-40cm)ranged from 1 429.8 to 2834.3t/hm2,effective capacity ranged from 325.9to 882.7t/hm2,capillary water holding capacity ranged from 1103.8to 2131.0t/hm2,soil wate-holding capability of natural secondary forest was relatively stronger than plantation, initial infiltration rates(0-20cm)ranged from 0.28to 21.1mm/min,and initial infil-tration rates(20-40cm)ranged from 0.07to 6.7mm/min,steady infiltration rates(0-20cm)ranged from 0.14to 8.3mm/min,steady infiltration rates (20-40cm)ranged from 0.05to 2.0mm/min,initial infiltration rates and steady infiltration rates of natural secondary forests were relatively stronger than plantation.A power function can be used to describe the relationship between soil infiltration rate and time.}

Abstract:The distribution characteristics of available copper in Wangmao gully watershed of Northern Shaanxi Province were investigated using a stratified sampling method.In the studied watershed,the mean value of available copper was higher than the critical value in the loess area.Effective soil copper was found high in slope areas of gullies and low in slope areas of mounds.In terms of slope aspects,the sequence of effective soil copper was semi-sunny slope>sunny slope>semi-shaded slope>shaded slope.The strongest correlation between effective soil copper and soil organic matter was identified in the soil layer of 20-30cm.The research provides solid evidences for studies regarding the distribution of soil trace elements in Loess Plateau region.

Abstract:Land use patterns from 1970 to 2000 were analyzed to determine the changes in the study area.On this basis,long-term hydrologic impact assessment(L-THIA)model was used to evaluate the long-term average non-point source(NPS)pollution loads and to simulate their spatial distri-butions.Unit contribution index(UCI)was introduced to assess the impacts of various land-use categories to annual average NPS pollutant production.The results are as followed.(1)From 1970to 2000,farmland,forest and grassland were the primary land use types in this area,ecolo-gical land area decreased dramatically with rapidly increased nonecological lands,implying intensified human activities and the tendency of ecological recession.(2)During the past 30years,NPS pollution loads rose from 0.34million tons to 0.62million tons;the areas of high TN and TP loads distributed mainly in the middle reach but has expanded to the upper reach considerably.(3)Contribution rate(CR)and UCI were calcu-lated to analyze the relationship between land use types and NPS pollution,with UCI reflecting more closely the impacts of land use change to NPS pollution.Farmlands had the most significant impact on NPS pollutants and were identified as the main source,followed by residential and industrial lands,and forest and grasslands.

Abstract:In regard to the problems of soil and water loss,environment pollution and the deteriorating self-purification ability of the water body in Three Gorge areas,constructing ecological barriers in the lakeside zone in accordance with regional development mode will provide ecological security and sustain socioeconomic development of the reservoir and the downstream areas.Taken the demonstration area in Panlong town,Yunyang County as an example,the paper discussed functional zoning,and construction target and principles for ecological barrier construction in the lakeside zone,based on field survey on natural conditions and socio economic situations.The preliminary technical system,including over twen-ty constructional modes of nine categories,was proposed.The benefits were analyzed and evaluated in order to provide referential concepts and measures for ecological barrier construction in the surrounding regions of the reservoir.

Abstract:One of the most severely eroded regions in the world is the Loess Plateau,where gully erosion is one of most important research topics.In order to estimate gully erosion from geographic perspective,Majiagou basin in Shaanxi Province as the study site was investigated using 5m×5m DEM as experimental data,combining three-dimensional analysis and data mining method in GIS,along with contour simplification techno-logy in traditional cartography.The results mainly show that terrain indicators changed by simplifing a group of contours that consist of a gully,which is equivalent to that gully was virtually filled in the laboratory.This method as virtual restoration of terrain can be used to simulate the formation and development process of a gully or a system of gullies in long terms.The concepts and methods developed in this paper may have some enlightening values to estimate total erosion of a gully or gully system precisely.

Abstract:It is the object-oriented spatial-temporal model that breaks the limitations of relational models.The model directly supports object-oriented nesting and variable-length records.Therefore,with the incorporation of object-oriented database into object-relational database,the latter performs better in retrieving,updating and storing of the complex geographical data.In fact,the advanced characteristics of the objectorient-ed spatial-temporal model can be readily adapted for building geo-databases with a vast amount of information from various sources.For examp-le,a rocky desertification database often includes multiple sources and massive data with relative little variability.The spatial-temporal database system for rocky desertification is developed as an object-relational database system.Referring to the system structure of SQL Serve 2000,adopting the SDE administrator command method with ArcSDE data engine interface,and using component object model library of ArcGIS Engine 9.2,seamless integration of the spatial data warehousing and complete client-side GIS development and applications were realized in Microsoft VB 6.0circumstance.As a result,a spatial-temporal database aiming at rocky desertification and remote sensing is built up with C/S operated mode.In conclusion,the database system achieves four major functions,including(1)map searching,spatial analysis and result display-ing of rocky desertification land degradation;(2)information searching in regard to rocky desertification along with statistical analysis and data tabulation by using attribute database;(3)real-time database updating with remote sensing database(4) forecasting rocky desertification and land degradation using algorithmic models.

Abstract:In the present study,the model for cotton-root water uptake with drip-irrigation under mulch film was established based on field experiment. With the model,water dynamics and redistribution was addressed under the condition of cultivation.The fundamental mechanisms of water uptake by cotton roots were carefully discussed.Core samples were collected by drilling separately in wide rows and narrow rows of cotton plants,and the root samples were then separated by water from the soil cores for measuring root lengths.Based on the root lengths,a distribution model was developed regarding root length density of cotton.Based on theoretic analysis and mathematical calculation,one-dimensional cotton root uptake model was built by incorporating factors such as root length density,soil moisture content and plant evaporation.The model had a simple structure with only a few parameters.The cotton root uptake model matched well with field observation and is readily to be applied.

Abstract:As the foundation for regional soil erosion model,Regional Soil Lose Model can be used for regional rainfall runoff and sediment forecasting, soil and water conservation and environmental issues to support regional macro decision-making.Currently,the model cannot be used effectively for large areas due to its slow computing speed.Aiming at the problems,this paper analyzed the model process and incorporated network parallel computing methodology and corresponding task scheduling rules into the model.The results show that the running time greatly reduced in the revised model and the computational efficiency significantly improved.This method provides a way to solve the problem caused by huge amount of data in GIS model with a feasible scheme.

Abstract:Soil evaporation is an important component of water consumption of the Taklimakan Desert Highway Shelterbelt.Micro-Lysimeters were used to measure soil evaporation within an irrigation cycle at different distances from the trees drip-irrigated with saline water.Meanwhile,the relationship between soil evaporation and water surface evaporation was analyzed,and soil moisture evaporation was estimated through onedi-mensional adjustment processing.The results show that a spatial-temporal variation pattern of soil evaporation can be clearly identified in the shelterbelt:at the starting stage,the order of soil evaporation was tree base>50cm from tree base>100cm from tree base;and after the 5th day,the order was 50cm from tree base>tree base>100cm from tree base.Soil evaporation in the shelterbelt decreased with soil water contents. The estimation shows that annual total soil evaporation of the shelterbelt will be approximately 2.63×10⁶m³with drip-irrigation using saline water,accounting for 21.43% of total irrigation volume,and soil evaporation in a growing season accounts for 92.28%of annual soil evaporation.As soil evaporation results in such a high amount of water loss,appropriate measures may be required for reducing soil evaporation and improving water use efficiency.

Abstract:Hetao irrigation district is the largest single gravity irrigation district in China and even Asia.At present,the main problems of field irrigation in Hetao irrigation district are lack of water source,irrigation structure aging,low engineering standards,slow promotion of water-saving irrigation techniques,serious waste of irrigation water and others.To solve these problems,Hetao irrigation district should take account of some integrated technologies,such as engineering,agricultural,chemical,and management water saving,etc.Engineering water saving should start from channel lining,laser land leveling,small plot irrigation and others.At the same time,water-saving irrigation should be promoted actively and the groundwater should be use rationally.Agricultural water saving should focus on cultivation planning,agronomic water saving,deep plowing,straw returning,and surface evaporation reduction.Chemical water saving could be active promotion and application of drought-resistant reagents,super absorbent polymers,and other chemical regulation agents.Management water saving could include water manage-ment strengthening,system improving,and establishment of water user associations.

Abstract:Soil information system(SIS)has become a hot topic in soil science.It is imperative to establish Qinling-Bashan SIS due to the special geographical characteristics and the conflicts between limited soil resources and demanding agricultural production in Qinling-Bashan Mountain.This study collected a variety of soil data and related information,and established the soil database with the support from GIS.On this basis,SIS was developed with using C#.net plus ArcEngine,which achieved GIS basic functions of query and analysis,application modules including land evaluation and so on.The system will provide scientific basis for the prevention and control of soil erosion,sustainable development of agricultural production and related decision-making in Qinling-Bashan Mountainous area.

Abstract:In the arid and semi-arid loess hilly region,water is not only a survival factor,but can also be a hazardous element sometimes.Aiming at ensuring the security and stability of artificial dumps and the water demand of vegetation growth,this study took the reclaimed lands of opencast mines in Pingshuo County of Shanxi Province as the study sites,conducting field survey and data analysis.The preliminarily water-control technologies of the last 20years were divided into three reclamation stages,i.e.,landform reshaping,new land creation,and ecology system rehabilitation.The key technologies of water-controlling included conducting water in dump bases along with layer-by-layer compaction of the dumping materials,controlling runoff by water network construction and sub-basin fragmentation,and conserving water resources with considerations of both storage and drainage.Water regulating should be paid attention during the whole course of dump reclamation.Runoff utilization would be the major part of water conditioning in the middle or late stages of dump reclamation.Further studies are required for many other specific issues regarding water regulating in this area.

Abstract:A zonal evaluation of water resource use in the fourteen cities of Hu'nan Province was carried out using the osculating value method. Accord-ing to the scatter plot of the osculating values,the utilization level of water resource was categorized into three zones:(1)weakly developed zone,(2) moderately developed zone,and (3) highly developed zone.A detailed map was drawn based on the classification.The results show that among the fourteen cities,five cities were classified as weakly developed zone,six cities as moderately developed zone and three cities as highly developed zone.The weakly developed zone accounts for 35.7%of the total area.Overall,the water resource use in Hu'nan Province is imbalanced.Appropriate practices are need in areas with different development levels.

Abstract:Currently a satisfying evaluation method has not been developed for the forest ecosystem evaluation yet.Based on the Costanza's method,XIE Gao-di introduced the equivalent weight factor method.In 2008,the Institute of Forest Eco-environment and Protection,Chinese Academy of Forestry promulgated the evaluation criterion of forest ecosystem(LY/T1721-2008).Taking the riverhead forest ecosystem of Qiupu River in Chizhou City,Anhui Province as an example,the two methods were applied to calculate the service value of the forest ecosystem as approximate-ly1.13×10⁸Yuan and 4.94×10⁸Yuan,respectively,in 2007.This large disagreement between two numbers could be attributed to the background behind which the methods were created,different concepts,index types and included parameters.Equivalent weight factor method was created based on conditional values,reflecting objectively the people's willingness to pay(WTP).However,it maybe not theoretically precise.LY/T1721-2008assessment method emphasizes more on theoretical application and is therefore more precise and accurate.However,its results may deviate considerably from the people's willingness to pay.

Abstract:The flow data of Jiangjia Canyon from 2008to 2009was collected and annual variations of the stream flow were analyzed.A database of soil,land use and meteorological parameters was built based on the field survey and experiments,and monthly flows and daily flows were then simulated using the SWAT model in the canyon.The simulations of monthly flows were relatively better in the dry seasons than in the rain seasons,owing to the lack of observations during the rainy seasons when debris flows frequently occurred.Daily flows were simulated separately for the dry seasons and the flood period.The Nash efficiency and correlation coefficients of daily flow simulation in both rain season and dry season were higher than 0.7,which implies that the model can be successfully used in this area.This paper contributes to the study of rainfall-runoff mechanism in Jiangjia Canyon.

Abstract:Based on grain size analysis and soil moisture determination,soil moisture environment,causes of steppe degeneration,and vegetation suitable to developing were investigated at Shaliuhe Town in northern Qinghaihu Lake.The results show that the soil in the studied area is mainly composed of coarse silt.Soil moisture was rich in 2009as a rainy year,and the seeping depth of gravity water reached 1.3min the rape land and about 0.5min the grass land,respectively.Soil moisture contents differed for various vegetation types,but decreased consistently with the depth.Soil moisture contents 0.8munder the surface ranged from 8%to 11%for the majority of the grass lands,developing a weakly or moderately dried soil layer.This indicated insufficient soil moisture conditions and imbalanced water budgets,implying afforestation might not be suita-ble for this area.As dried soil layers extensively developed,drought-resistant grasses and other crops that consume less water are more desirable,in order to prevent water level recession of the lake.The cultivation area of water consuming plants like rape should be limited, and the exploitation of water resources from the rivers into Qinghai Lake should be well controlled.

Abstract:Taken Maotiao River watershed of Guizhou Province as a case study,this paper simulated the spatial distribution of soil erosion in 1973,1990 and 2007,respectively,using GIS and the RUSLE model.Current status of soil erosion and its dynamic change were characterized.The results could provide scientific guidance for soil erosion control in the study area.The results show that serious soil erosion occurred mainly in the lower and western upper reaches of Maotiao River watershed.The major sediment sources included the areas classified as strong,extremely strong and severe erosion zones.In terms of land use,dry farmland and grassland were the dominant land use types resulting in serious soil erosion.The total area of minimal and weak soil erosion zones reduced during the period of 1973-1990,while highly eroded areas increased significantly.During the period of 1990-2007,the total area of strong,extremely strong and severe erosion zones decreased significantly,with an increase of the total area of minimal soil erosion.Soil erosion occurred mainly on lands with a slope grade of 6°～25°,where more attention should be paid to and some practical measures should be taken to reduce soil loss.

Abstract:Transformations of natural river systems following tremendous cascade development greatly influenced the natural habitats and landscapes in Yun'nan province.Taking hydropower development of Yun'nan Province as an example,this paper analyzed the impacts of the hydropower develop-ment by relating hydropower development status and drought frequencies in the province.The results show that the construction of hydropower has caused a variety of environmental problems such as vegetation destruction and natural landscape fragmentation,biological habitat deterio-ration and species reconstruction,unbalanced hydro-environmental system,and so on.In order to cut down negative impacts on the environment, following protection measures were proposed,i.e.,(1)rational planning for watershed development;(2)standardizing construction procedures and carrying out environmental impact assessment with hydropower development planning;(3)establishing dispatching centers for cascade exploita-tion of the rivers;(4)enhancing environmental propaganda and related scientific research.

Abstract:The basic concepts of comprehensive evaluation of urban ecological revetments were clarified,and the insufficiencies of current index systems for the urban ecological slope evaluation were exposed explicitly.An ideal evaluation index system should reflect,scientifically and reason-ably, the requirements of an ecological protection system.Based on this concept,a comprehensive evaluation index system for the ecological revetments of Hefei City was developed.The system is consisted of four indices including types and materials of the construction,stability, functions,and social and economic benefits.The analytic hierarchy process(AHP)was then applied to evaluate engineering cases and the results were found reasonable.The system could provide a basis to evaluate ecological revetments in Hefei City and potentially significant guidance for urban revetment constructions.

Abstract:Ecological protection is a common method used for protecting expressway slopes.There was no unified and well-recognized standard to evaluate the protective effects of ecological slope engineering.Based on the domestic and international findings of the related studies,an attempt had been made to establish evaluating indicators accounting the quality of soil-vegetation system and the landscape functions with a view of systematical engineering.Further,the two types of indicators were divided into sub-indices for practical considerations.The appraisal stand-ard incorporated with the indicator system categorized engineering projects into four grades,i.e.,excellent,good,moderate,and poor,which reflect rationally the nature and characteristics of the structure and functions of the soil-vegetation system.The index system were used to evaluate the performance of isolated slope sections in a single ecological slope protection project of the Chifeng-Tongliao highway by combi-ning analytical hierarchy process(AHP)with the fuzzy comprehensive evaluation.The appraisal results coincided well with field observations, implying that the indicator system could be used to objectively evaluate performance and sustainability of the soil-vegetation system.

Abstract:Based on the historical documents of Wulate County from 1957to 2006,we analyzed the features and status of the cultivated land,and found that almost no more arable land could be found in the area and the conflict between man and land had been increasingly apparent.Principal compon-ent analysis was conducted to identify social economic factors influencing cultivated land changes.The results show that the growth of popul-ation along with economic development,and the modernization level of cultivation are the two major driving forces.Furthermore,the GM(1,1) model was applied to predict cultivated land area and gross population of Wulate County in 2010,2015and 2020,respectively.The prediction indicates a continuously increasing population companying by a continuously reducing area of cultivated land,implying a more severe conflict between man and land.The findings could provide scientific bases for protecting and urging sustainable usage of cultivated land in this region.

Abstract:By developing an evaluation index system and applying of analytic hierarchy process(AHP)comprehensive evaluation,an ecological risk assess-ment of the ecosystems in the Shitoukoumen Reservoir basin was carried out with considerations of natural conditions and human disturbance of the study area.Based on historical documents and field survey,three factors including point source pollution,non-point source pollution and drought were selected as risk sources.The results show that ecological risks of the basin displayed substantial spatial variability.The key ecological risk sources were total nitrogen and phosphorus in the water,with weight coefficients of 0.2247and0.1945,respectively.The results of this study provided quantitatively a theoretic basis and data support for the environmental management and ecological risk decisionmaking.

Abstract:Vegetation cover plays a major role in the restoration and stabilization of disturbed systems.Comparative plant successional studies on dump,using a space-for-time substitution in the short-term,are providing significant insights into vegetation dynamics to ensure the success of future revegetation projects in these areas.Waste dump at Yimin opencast coalmine,Hulun Beier,was surveyed for naturally occurring plant species.The vegetation compositions,importance value and plant species diversity were compared.Altogether 64 naturallyr R.occurring plant species,belong to 21families,were observed in different waste dumps of Yimin opencast coalmine.The main families wereCompositae(14 species),Gramineae(12 species),Leguminosae(6 species)andChenopodiacea(5 species),which accounted for 57.8%of total species.According to the important value of species calculated,it is determined thatTribulus terrestrisandSalsola collinaacted as pioneer species on waste dumps,andStipa grandis,Leymus chinensis,Artemisia sacrorumandArtemisia halodendron were important dominant species in vegetation restoration in Yimin opencast coalmine.The overall species diversity of plant communities shows that the longer the natural recovery years last,the lower Alatalo(Ea)index become,and there is a significantly negative correlation between the Alatalo(E_a)index and the number of recovery years.Margalef(M_a)and Patriek(P_a) richness indices showed a increase trend,Shannon-Wienerd(H′)and Simpson(D)diversity indices showed a similar growing trend.The composition of species was becoming increasingly similar to the native plant community,and the species diversity index of each recovered plant community was higher than that of the native plant community,which shows that these communities need more time to reach steady states.

Abstract:It is an exploratory research to quantitatively identify and comprehensively assess the benefit of the urban rainwater utility(URU),which can generate results helpful for decision making on the corresponding projects.Taken the rainwater utilization project in the Wafangdian industrial district as a case study,the index system of benefit assessment for URU was structured,the URU benefits were evaluated with a multilevel semi-constructive fuzzy optimization model,and an optimal scheme was then recommended.The results indicate that the multi-level semi-constructive fuzzy optimization model well met the needs of comprehensive benefit assessment of URU.The benefits of URU could be increased with enlarged reservoir volumes and/or infiltration enhancements.

Abstract:Due to the fact that land reclamation of subsided mining area is often of very low quality,this study developed the following three schemes to relieve the problem.First,the landowners should maximize the protection of arable lands,reduce the influences of land subsidence,guarantee the interests of farmers who experienced land subsidence,and sustain social stability.Secondly,the government should comprehensively reclaim subsided lands,and restore the economic values and benefits of the subsided lands.Thirdly,strengthening or remodeling schemes should be proposed for supportive structures to maximize economic and social benefits and to provide positive guidance for other subsided areas.The research area is one of largescale modernized mining coal fields of complex surface sturcture.The findings of this paper will provide practical guidance of reclaimation planning for the study area and other similar mines.

Abstract:Wenchuan earthquake caused a variety of secondary mountainous hazards.Risk assessment regarding secondary hazards is therefore very important for reconstruction projects in the affected areas.Based on regional data analysis,assessments of dangerousness,vulnerability,and risk were carried out.A linear relationship was found between dangerousness degree and disaster density.Assessment results show that highly dangerous regions concentrated along Longmengshan fault,accounting for 39.8%of the total area.Regions of high and extremely high vulnerability mainly surrounded the cities of Chengdu,Mianyan,Deyang,and Ya'an,accounting for 13.1%of the total area.Regions of high risk,accounting for 11%of the total area,occupied the transitional zone between Longmeng Mountain and the piedmont plain,which had high dangerousness degree and high vulnerability,respectively.Special attention should be paid to the regions of high risk and vulnerability during the reconstruction.However, the regions of moderate should also be cared as the risk and vulnerability of these areas could be potentially deteriorated due to the rapid expansion of the reconstruction areas.

Abstract:Great attentions have been paid on landscape pattern changes and the driving forces for rapidly urbanizing areas in recent years.Based on TM images of Foshan City in 1991and 2005,landscape metrics,landscape change driving forces index(LCDI)and landscape gradient index(LCGI)were selected to analyze the changes of landscape pattern and spatial gradient heterogeneity of driving forces with GIS and geostatistics.The results indicate that the landscape pattern changed remarkably from 1991to 2005.Changes of cultivated lands and constructional lands were dominant in the whole landscape change.The area of cultivated lands reduced greatly from 37.50%to 15.09%.Meanwhile,the total area of constru-ction lands increased 98570hm²during 1991-2005,with the highest LCDI value.According to the results of landscape metrics analysis, the fragmentation degree of cultivated lands and garden lands were relatively high,due to the intense human disturbances in these lands. Woodlands showed symmetrical spatial characteristics.Construction lands had the highest fragmentation degree of all the landscapes in the city,although strong spatial distribution centrality was found in constructional lands.Through spatial analysis on synthetic driving forces of the landscape changes,the spatial gradient heterogeneity became increasingly evident from 1991to 2005, closely related to landscape patterns and driving forces.Spatial gradient analysis on driving mechanism of landscape pattern change is proven helpful in identifying the relationship between landscape patterns and processes,which could potentially enhance our understanding of the pattern and direction hetero-geneity of landscape pattern changes.

Abstract:Irrational land use is the major force of the severe soil erosion and loss occurred in the Loess Plateau.Taking Majiagou catchment in Ansai county as an example,the characteristics and trends of land use/cover change were analyzed based on the first national land use survey maps in 1990(obtained from the Bureau of Landuse Survery of Ansai County)and the 2008land use map(mapped by field survey).In Arc-GIS,two types of land use maps were overlaid and the dynamic changes were analyzed.The results show that,from 1990to 2008,farmland and grassland decreased by 11.88%and 1.58% of the total area of the catchment,respectively.At the same time,forest,orchard and residential lands increased by 11.61%, 1.73%and 0.01%of the catchment area,respectively.The areal ratio of farmland,forest and grassland was changed from 3:1:6to 2:2:6during this period.The major transferring patterns among the land use system are grassland to forest,farmland to grassland,farmland to forest,and farm-land to orchard.Forest,orchard and farmland have relatively high changing rates of 8.06%,2.41%,-2.43%,respectively.Although the forestry area has increased over the past20years,it remains as an artificial ecosystem with the nature of instability and non-sustainability.The deployment of the national policy of“Grain for Green”since 1999and the substitution of farmers'operating strategies can be contributed to the increase of forest and orchard areas in the studied region.

Abstract:In the water source areas of Beijing City and Tianjin City,ecological environment is highly fragile,and soil and water loss often exhibits strong spatial variability and occurs unpredictably.Along with data of climate,soil,terrain,land use and vegetation coverage,soil erosion and its spatial differentiation were studied based on the revised universal soil loss equation (RUSLE)model and geographic information system (GIS),in Xibeigou watershed of Luanping County,Hebei Province.The results show that the annual average rate of soil erosion was3816.835t/(km ²·a),classified as middle-grade erosion.Annual average of potential soil erosion was 31583.15t/(km²·a),about 8.28 times of the former.Meanwhile,soil loss was obviously spatially differentiated.Among different land uses,sporadically distributed farmlands with steep slopes had the strongest soil erosion intensity,and next to it was highly weathered and degraded grassland's,which accounts for 59.38% of the total area of the watershed and 88.48% of the total sediment as the main source of the soil loss.With the increasing slope,the soil erosion intensity increased markedly.Approximately one third of the total area of this region has a slope degree higher than 25°,while this proportion contributed two third of soil loss.Soil losses also differed among lands of various aspects,as in order of sunny slope>half-sunny slope>half-shady slope>shady slope>flatland.

Abstract:Based on the ratio of ecological deficit to per capita ecological footprint,evaluation criteria of ecosystem health were established in regard to ecological footprint for Bijie District.Using ecological footprint demand and ecological carrying capacity with consideration of fossil fuel consumption,the per capita ecological footprint demand of Bijie area was 2.9703hm²,per capita supply of ecological footprint for regional development was 0.2679hm²,per capita ecological deficit was-2.7023,and the ratio of per capita deficit to ecological footprint was-0.8779.The ecosystem of Bijie area as a whole is in an unhealthy state.Taking fossil fuel consumption out of the account,Bijie area and its eight counties were in sub-health or unhealthy states.In terms of the spatial pattern,the ecosystem health of Bi-jie area deteriorated from northwest to north,south and east directions.Without considering fossil fuel consumption,the ecosystem health of the area also deteriorated from the center to the surrounding areas.Fossil fuels,economic development,and population size and density impacted greatly the mountainous ecosystems of the exposed area the karst plateau.