Abstract:Selecting 4 erosion factors of rainfall erosivity,soil erodibility,topography undulating degree,and vegetation coverage,this paper evaluated the effects of the returning farmland to forest project(RFFP)on the changes of soil erosion sensitivity with the aid of USLE and GIS.Results showed that mild sensitivity and moderate sensitivity were the main sensitivity types and their area proportions were 39.61% and 29.04% before the RFFP and 37.79% and 34.03% after the RFFP,respectively.In the south,non-sensitivity and mild sensitivity were the main sensitivity types and in the southwest,the non-sensitive area increased.In the north,the moderately,highly,and extremely sensitive types embedded each other before the RFFP,but the distribution pattern of them became obviously regular after the RFFP.Before the RFFP,soil erodibility played an important role in erosion sensitivity,while the role of rainfall erosivity was quite ordinary.After the RFFP,the effect of soil erodibility decreased sharply,while the rainfall erosivity increased quit obviously.In a word,the RFFP has improved soil erosion sensitivity.The need for soil and water conservation is still urgent in the highly and extremely sensitive regions.

Abstract:Two branch gullies of Chenjiagou,Wanzhou District in the Three Gorges Reservoir area were taken as the study object and the correlation of rainfall factor with runoff depth and peak flood amount was studied by grey relational analysis and correlative relationship.The data of over 10 typical rainfall events and the data of runoff in the small watershed firstly were processed by the line cutting method of base-flow separation.Results showed that by grey relation grade,the main influencing factors of runoff depth were found to be the rainfall amount(P),and compound factor(PI,the composite of rainfall amount and averaged rainfall intensity).In comparison of the grey relation grades for the two neighboring branch gullies,the grey relational grades of runoff depth responded to rainfall were different,but they had some common trends:the combined effect of peak rainfall intensity(I_60),and rainfall had a noticeable impact on runoff in the Three Gorges Reservoir area and the main influencing factor of peak flood amount was the compound factor(PI).

Abstract:Seepage field and stability on typical slope covered by unsaturated granite residual soil under rainfall infiltration condition are analyzed based on saturated-unsaturated seepage theory.Results show that maximum pore water pressure and volumetric moisture content in surface soil on slope increase with increased rainfall intensity and duration and present an increased large-small-large trend down slope.Slope stability significantly declines in initial rainfall stage and the downward trend changes slowly to a stable value with increased rainfall duration.When rainfall duration is short,rainfall intensity only changes pore water pressure distribution and water content in surface soil on slope.So the effect of rainfall intensity on shallow slope slipping can not be ignored.Because matrix suction can greatly influence slope stability,impact of suction on slope stability in engineering design should be considered.

Abstract:The soil physical characteristics on five types of degraded alpine grasslands in Maqu County in the Upper Yellow River were studied.Results showed that soil bulk density,porosity,moisture capacity,and water storage capacity in 0—30 cm soil layer of the five degraded grasslands were significantly different.Soil bulk density increased with the aggravation of degraded alpine grasslands and also increased with the increment of soil depth.The corresponding values ranged from 1.085 to 1.447 g/cm3 and 1.111 to 1.248 g/cm3,respectively.Soil total porosity,maximum moisture capacity,and total water storage capacity decreased with the aggravation of degraded grasslands,their range values were 46.214%~58.162%,26.765%~52.369%,and 1 386.420~1 744.872 t/hm2,respectively.The soil physical characteristics decreased with the increment of soil depth and the range values were 52.783%~57.285%,40.504%~50.057%,and 527.833 t/hm2~572.852 t/hm2,respectively.Soil permeability firstly decreased with the aggravation of degraded grasslands and then increased.By soil permeability,the order of grasslands was moderately degraded grasslandslightly degraded grasslandheavily degraded grasslandnon-degraded grasslandextremely degraded grassland.Study of infiltration process indicated that soil permeability of non-degraded grassland was good and its water conservation function was better than heavily degraded grassland.

Abstract:Stem sap flow of a plant can indicate water consumption by transpiration and accurately reflect the transpiration of plants and water utilization.In this study,Dynamax sap flow measuring system and automatic weather station system were used to simultaneously measure and monitor sap flow velocity and related environmental factors of the artificial shrub Atraphaxis bracteata in the Mu Us sandy area.Results showed that(1)the diurnal variation of stem sap flow of Atraphaxis bracteata presented a multi-peaked curve.At night,there was still stable flow of low value.The magnitude of sap flow changed considerably between sunny and rainy days.(2)Throughout the growing season,the total sap flow is 428.83 L,with the average daily sap flow of 2.639 5 L/d.(3)The flow rate of Atraphaxis bracteata was positively correlated with some ambient environmental factors.Correlation analysis showed that by the coefficients from correlation analysis,the order of factors was solar radiation air temperature air relative humiditywind speed.

Abstract:Based on the meteorological data from China meteorological data sharing service system,climate change of Weihe River basin and its regional difference from 1951 to 2007 were analyzed.Results showed that the annual maximum wind speed and the average wind speed presented a decreasing trend,but they have no significant change in recent years and were less than the average.The annual precipitation of Weihe River basin had no abrupt change,but on the whole,the average annual precipitation after 1987 was significantly less than that before 1987.The days for ≥ 0.1 mm daily precipitation after 1993 were less than average,but had no significant change from 1993 to 2007.The annual mean temperature and the minimum temperature of the basin showed a increasing trend,rising at the rates of 0.544,0.509,0.386,and 0.667 ℃/10 a,respectively.The rates were all far greater than the average global warming rate of 0.13 ℃/10 a in nearly 50 years,which indicates a great increase in the annual temperature.Number of sunshine hours in Weihe River basin showed different characteristics.The change of sunshine hours was also different in different regions.In the northeast,sunshine hours showed an increasing trend,but in other regions,showed a decreasing trend.Relative humidity of Weihe River basin showed an obvious decreasing trend.The climate change of Weihe River basin showed a warming and drying trend.

Abstract:This study aimed to explore the characteristics of the vertical distribution of the conversion between soil erosion degrees by taking the Yimeng mountainous area,one of the most representative areas in the rocky area of Northern China,as a case study.The study was based on the national standards for classification and gradation of soil erosion and supported by the GIS and RS technology and the data from Landsat TM image and relief map.Results showed that from 1986 to 2004,soil erosion was mainly converted to minimal degree and adjacent degrees.The area of aggravated soil erosion was 810.7 km2 and the area of alleviated soil erosion was 1913.8 km2,accounting for 7.15% and 16.88% of the total changed area,respectively.About 81.51% of the aggravated areas and 73.43% of the alleviated areas occurred between 150 and 400 m above mean sea level.The areas for all the soil erosion degrees ascended at first and then descended subsequently with rising elevation.Elevation for peak value of the erosion area rose with increased soil erosion degree.Elevation ranges for minimal,slight,and moderate erosion degrees rose with increased soil erosion degree.Locations of the elevation range from intense,very intense,and severe erosion to minimal degree were relatively low and those from very intense and severe erosion to moderate degree were relatively high.

Abstract:An investigation of Ulmus pumila var.sabulosa was carried out in the different habitats of Hunshandake sandy land,including both seedling density and seedling growth.Seeding density of dispersal under single trees and the edge of forest was studied.Its natural regeneration was analyzed using population ecology method and mathematical statistic method.Results showed that by seeding density,land units was in the order of shifting dune semi-fixed sandy land fixed sandy land.Seedlings grew badly in fixed sandy land and shifting dune and seedling death phenomenon was serious in shifting dune.Seedlings grew well in semi-fixed sandy land.Compared with fixed sandy land and shifting dune,semi-fixed sandy land was suitable to the habitat of natural regeneration.Seedlings were mainly distributed within the area 20 m from the edge of forest and outside 20 m,seedling density was reduced obviously.Wind direction had greater influence on seedling density and by seeding density.

Abstract:Soil physical and chemical properties in Rhodolcia championii stands with different densities(1 667,2 500,4 444,and 10 000 trees/hm2)were determined using conventional methods to utilize soil resources reasonably.Compared with other stands,soil bulk density in the stand of 10 000 trees/hm2 was great and its aeration ability was weak.Contents of soil organic matter,N,P,and K in the stand of 2 500 trees/hm2 were high among the four stands,indicating that its effect on soil improvement was better than the other stands.In the stand of 4 444 trees/hm2,soil organic matter and N contents were relatively high,P content was medium,and K content was high.The result indicated that the stand was favorable for soil nutrient accumulation.In the stand of 1 667 trees/hm2,soil organic matter and N contents were medium,P content was high,and K content was relatively low.As a result,the stand significantly improved soil P condition.Contents of soil organic matter,N,P,and K in the stand of 10 000 trees/hm2 were low,which indicated that the stand was unfavorable for soil nutrient accumulation.

Abstract:This study was based on the precipitation data since 1960 from 17 weather stations in Xilinguole League and related areas.The interdisciplinary knowledge between meteorology and ecology was used and eco-geographical regions were divided according to the meteorological stations.The cycle regularity of precipitation and the difference among the eco-geographical zones were discussed with the aid of wavelet analysis method and Matlab software.Results showed that there was obvious cyclical change of precipitation sequence in Xilinguole League at the inter-annual scale from 1960 to 2007.There was an obvious signal of 25~32 year cycle of annual precipitation in 4 eco-geographical zones,but the periods of lack and abundance precipitation were different among the zones.According to the cycle characteristics,we can infer that in the next 15 years after 2007,Xilinguole League and related areas are in a state of persistent drought.

Abstract:Sap flow of Robinia pseudoacacia and Quercus variabilis in the city west mountain area of Beijing City was systematically measured from May to September of 2008 using thermal dissipation sap flow probes,combined with environmental factors.Diurnal variation of sap flow displayed a wide-peaked or double-peaked curve on sunny days and a multiple-peaked curve on overcast and rainy days.In May and June,the averaged sap flow velocities of R.pseudoacacia were 1.58 and 1.08 times slower than those of Q.variabilis,respectively,and in July,August,and September,1.391,1.408,and 1.450 times higher,respectively.In May and June,sap flow velocities of Q.variabilis were significantly faster at upper heights than median and lower heights and from July to September,faster at lower heights than median and upper heights on typical sunny days.During the season of rapid growth,sap flow velocities of both tree species were positively correlated with solar radiation intensity,atmosphere water potential,and vapor pressure deficit and negatively correlated with soil water potential.Multiple linear regression equations for environmental factors with sap flow velocity were established,which all met the significance at 0.01 levels with F test.

Abstract:Using the methodology of "the temporal for the spatial",this paper studies the relation of soil physicochemical properties and soil enzymatic activities with plant organic C and total N in different desert lands in Yulin Prefecture,North Shaanxi Province.Results showed that with the process of increasing desertification,soil physicochemical properties changed regularly.At the same time,soil pH value in different profiles at the same desertification degree increased with soil depth increasing and soil urease activity was reduced sharply although the variation of soil pH value was not so obvious.Soil catalase activity in the whole profile was relatively higher and it first decreased and then increased with profile depth increasing.Correlation analysis showed that in the study area,there was little relevance between soil pH value and other factors and a close correlation among all factors except soil pH value.Except plants and the soil C/N value,the correlation between soil bulk density and other indexes was negative and the correlation among other indicators was positive.

Abstract:The fraction distributions,availabilities,and mobility of Hg,Ni,Cd,Cr,Zn,As,Cu,and Pb in municipal sludge of Nanchang City were investigated.Results showed that the extraction percentages of Pb and Cr by Tessier's sequential extraction procedures were 96.5%～94.6% and 90.1%～90.3%,respectively.The sums of each fraction of heavy metals were in agreement with the total contents of heavy metals,which means that the fraction distributions of heavy metals in the municipal sludge given by Tessier's method were reasonable.There were significant differences in fraction distributions of heavy metals in the two kinds of municipal sludge(QCSS and ZCSS)and among the different fractions of the heavy metals.By the availabilities of heavy metals,the heavy metals in QCSS were in the order of HgNiAsCdCuCrZnPb and by the mobility of heavy metals,HgNiCdCrZnAsCuPb,respectively.In ZCSS,the corresponding orders were CrHgCuCdNiZnAsPb and CrHgCdNiZnCuAs≈Pb,respectively.The result may provide a scientific basis for the harmful assessment of heavy metals in the agricultural utilization of sewage sludge.

Abstract:In the matter of geological hazards,Pengyang County is in extraordinarily severe situation in Ningxia Autonomous Region.Through the analysis of the data of regional geological environment,a detailed investigation of geological hazards in Pengyang County is completed by means of remote sensing interpretation and ground investigation,in the manner of the combination of point,line,and area surveying.Results from the investigation show that landslide,collapse,and unstable slope are the main types of geological hazards in the county,with the typical characteristics of geological hazards in loess region.They present zonal and concentrated features in view of temporal and spatial distribution.Landscape,stratum structure,rainfall,and human engineering activity are considered as the main formation conditions of geological hazards.

Abstract:In order to improve the efficiency of land use and achieve the high yield and benefit of alfalfa in the arid area of northern Weihe River basin,the growth status of alfalfa both on shady(east)slope and sunny(west)slope was investigated and simple correlation analysis,partial correlation analysis,and path analysis were made for selected three characters of alfalfa.Results show that in the same slope aspect but different slope positions,alfalfa yield and the growth conditions of physiological characteristics on lower slope are superior to those on uphill.In the same slope position but different aspect,the growth status of alfalfa on the shady slop is better.The best growth condition is on lower shady slope and the worst,on upper sunny slope.Effect of slope aspect on alfalfa yield is greater than slope position.The simple correlation coefficients on plant height,branch number,and single-stem weight are very significant,but the path coefficient and decision-making factors vary greatly.Plant height and branch number play a direct role in yield.The direct effect of single-stem on biomass is not significant,whereas plant height and branch number play an indirect role in biomass.

Abstract:Through point-survey for farmland shelterbelt system situation,windbreak effect,and yield performance in Jingdian's first and second irrigation areas,the functions of the shelterbelt and its ecological effects were analyzed.Results indicated that eco-protection effect was displayed remarkably in the shelterbelt's two side of the 0~6H.With the distance from the shelterbelt increasing,eco-protection efficiency weakened gradually.Eco-protection effect was improved with the increase in stand age.In the perfect area of forest network,agricultural production benefits were significant and wheat yield and maize yield were 18.3% and 13.7% more than those in control area.Thousand kernel weight in the forest network area increased by 15%～18%.However,the effect of yield-increasing by shelterbelt was reduced in unsound forest network.Results from the comprehensive analysis show that economic and ecological effects of farmland shelterbelt in the area should be further improved.

Abstract:The effects of tree species(Picea crassifolia,Pinus tabulaeformis,and Platycladus orientalis)on gray-brown soil properties and water conservation in Qilian Mountains are studied.Results show that by total soil porosity,soil granular-structure,and soil clay content,tree species are in the order of Picea crassifolia Pinus tabulaeformi Platycladus orientalis;by soil density and soil sand content,in the order of Picea crassifolia Pinus tabulaeformis Platycladus orientalis;by soil organic matter and CEC,in the order of Picea crassifolia Pinus tabulaeformis Platycladus orientalis;by CaCO_3,pH,and total soil salt,in the order of Picea crassifolia Pinus tabulaeformis Platycladus orientalis;and by soil water storage and litter holding capacity,in the order of Picea crassifolia Pinus tabulaeformis Platycladus orientalis.

Abstract:Based on the analysis of soil aggregate content in runoff plots,the composition and distribution of black soil aggregates on sloping farmland with different slope degrees are discussed.Results show that both the content of large soil aggregates and the content of medium soil aggregates have significantly negative correlation with slope degree in 3°~18° plots.With slope degree increasing,geometric mean diameter(GMD)and mean weight diameter(MWD)decrease evidently,soil anti-erodibility decreases,and potential erosion risk increases.In 3°~6° plots,D_50 value for cross tillage is higher than that for no-tillage,but in the upper of 9° plot,D_50 value for cross tillage is higher and in the lower of 9° plot,D_50 value for no-tillage is higher.This indicates that cross tillage mode is beneficial to maintain the amount of black soil aggregates on gentle sloping farmland and soil in the lower of 9° plot under no-tillage has strong anti-erodibility.

Abstract:The characteristics of soil pH,organic matter,available nitrogen,available phosphorus,and available potassium in Hani Terrace paddy soils in Luchun County,Yunnan Province were studied.Soil samples were collected in the three sections of Guidong River patch,Songdong River patch,and Erhaohe River patch.Three kinds of Hani Terrace paddy soils,i.e.,non-erosion,erosion with one year remediation,and erosion with eight year remediation,were analyzed.Results show that(1)in the paddy soils,soil pH value is between 5.21 and 6.79;soil organic matter content,between 3.8 and 47.14 g/kg;soil available N content,between 39.51 and 137.47 mg/kg;soil available P content,between 1.29 and 13.31 mg/kg;and soil available potassium content,between 33.32 and 178.90 mg/kg.Spatially,soil nutrients at the same place of the paddy soils keep stable and have no significant variation,but at different places,they have some differences.(2)In the paddy soils,basic nutrients in non-erosion area are much higher than erosion area.Nutrients in the paddy soils have been increased by rehabilitation and field management and soils in terraces have been resumed for 8 years after soil erosion occurs.Most of nutrient contents are significantly higher than those only resumed for one year.(3)Basic soil nutrients at the same foothill but different altitudes in Hani Terrace of Luchun County are different,but vertically,nutrients have no obvious regular changes with increasing or decreasing of altitude.

Abstract:Wenchuan Earthquake not only induced a large amount of collapses and landslides immediately,but also reduced the strength of rock and soil mass in drainage basin,which makes them to be eroded more easily,so that abundant solid matter is provided for the formation of debris flows.The occurrence of debris flow is frequent in the disaster area after the earthquake and great losses have been caused.Evaluation on the risk degree of debris flow ditches is a necessary condition for post-disaster reconstruction.Three important parameters,i.e.,increment of solid matter,seismic intensity,and scale of barrier dam,are selected and evaluation method on increase coefficient of debris flow risk degree after earthquake is put forward based on designed debris flow.In this method,increase of debris flow risk degree is expressed by the ratio of added volume of solid matter to gross obtruding matter in a debris flow,seismic intensity multiplying the ratio,and time(hour)needed to drain water body in barrier dam with P_50% flux of the valley.By the validation of calculation for 9 typical debris flow ditches in the disaster area,the increase of debris flow risk degree in the May 12th disaster area after earthquake can be assessed by the new method,rapidly and precisely.

Abstract:To analyze soil physical and chemical properties in successive Eucalyptus plantation , principal component analysis(PCA)is used by determining principal component factors of soil.Principal component factors in different Eucalyptus generations are compared to illustrate the change of soil fertility .Results show that principal components in 0—20 and 20—40 cm soil layers are basically the same in Eucalyptus plantation .The first principal component composed of soil physical properties and the composition of three soil nutrients(N,P, and K)is the most important factor to soil fertility in the plantation .Integrated soil fertility declines with the increase of crop-rotation generations ,especially after the 3rd generation .Integ rated soil fertility is significantly reduced , compared with 1st and 2nd generations .The result indicates that maintaining good soil aeration and water permeability of soil , as well as N,P , and nutrient contents , is very important for maintaining the sustained and healthy development of Eucalyptus plantation .

Abstract:Soil erosion and water pollution are increasingly serious at present.This study aimed at ecological problems in Andi Reservoir catchment.Based on the investigation of vegetation and forestry ecology conditions,scientific design and implementation of forestry ecological restoration were made by applying advanced afforestation technologies including basin ecological restoration,forestry health management,production and management of ecological forest and fruits and adopting mountain closing for forest regeneration,cropland conversion to forest,engineering afforestation,and construction of demonstration areas.The approach to forestry ecological restoration in the catchment was discussed.

Abstract:This study adopts an improved method of the rough set.In view of the typical moraine-dammed lakes in Tibet,China,it is proposed that the moraine lakes prone to outburst often have the five characteristics of steep glacial relief of moraine lake area,frequent glacial activities,large scale of moraine lakes,poor stability of moraine dam,and wet-hot climate condition.Based on the characteristics,evaluation factors are selected in the hazard assessment of moraine-dammed lake outburst.Then,weights are determined for the factors in consideration of practical survey result and verified by fuzzy comprehensive evaluation.By the weights,it can be concluded that the most important factor on outburst is the stability of moraine dam(weight value 0.42),the second is the climate condition(weight value 0.18),and the other three are closely equal(each weight value about 0.13).Width of moraine dam and warm-humid combination are the important influencing factors;lake-glacial distance,lake area,and altitude height are the secondarily important influencing factors;moraine distal flank steepness and average particle size of moraine dam are the ordinary factors.The result of fuzzy comprehensive evaluation is consistent with that of practical survey,so the weights of the high accuracy can be of great reference value to the hazard assessment of moraine-dammed lake outburst in China.

Abstract:In order to investigate the effects of no tillage measurements on water holding capacity,grain yield,and production income,an experiment of different tillage ways was conducted in Yangling District,Shaanxi Province in 2007.Results showed that soil moisture was 1.2% higher in no tillage treatment compared with traditional tillage.Moreover,root length of corn in booting stage under no tillage was 26.6 m,71.6% more than that in traditional tillage.Finally,grain yield was 8 408 kg/hm2,which was increased by 11.3%,and production income was increased RMB 1991 yuan more than traditional tillage.The conclusion is that no tillage with straw mulching can efficiently increase soil moisture and evidently increase grain yield and production income.The sowing technology can be used in Guanzhong irrigation area and similar regions.

Abstract:By constructing multi-surface flow wetland,the effects of wetland system were examined and the control of rural non-point source pollution around Poyang Lake was discussed.Results showed that the total reductions of COD,TP,NO-_3—N,and NO-_2—N in the wetland system were 608.46,3.22,8.14,and 0.62 kg/a and the reductions of COD,TP,NO-_3—N,and NO-_2—N per hectare were 3976.83,21.04,53.21,and 4.05 kg/(hm2·a),respectively.The removal rates of COD,TP,NO-_3—N,and NO-_2—N in the wetland system were 48.9%,73.5%,58.7%,and 54.7%,respectively,and the COD and TP removal mainly occurred in the first reed wetland.Because the constructed wetland had a strong function of recovering oxygen,denitrification of NO-_3—N was limited.In order to enhance NO-_3—N removal rate,we discussed the mechanisms of nitrification and denitrification in wetland system and put forward the effective measure that part of the wastewater drained directly into the end of three wetlands and the end of three wetlands changed into subsurface flow wetland.In short,the wetland system not only provided a technical foundation for the control of rural non-point source pollution around Poyang Lake,but also afforded a demonstration for other lakefronts.

Abstract:Based on field experiments carried out in Yangling,field application efficiency is simulated by SRFR software and simulated values are then compared with measured values.Results show that the margin of error is reasonable,indicating that SRSF software is appropriate for the analysis of border and furrow irrigation.According to the simulation by SRSF software,optimum combination of reasonable irrigation technique elements under different conditions of border irrigation and furrow irrigation is found through changing the combination of irrigation technique elements.The result from the study may be useful in avoiding waste of water resources,enhancing irrigation application efficiency and distribution efficiency,and attaining aim of saving water.Meanwhile,the method can provide some references for other regions to formulate a scientific irrigation scheme.

Abstract:Based on the debris flow data collected from 129 villages and towns in the Anning River valley of Liangshan Prefecture,two multi-classification support vector machine models were built to evaluate debris flow hazards of the villages and towns.86 samples from the villages and 65 samples from the towns were randomly selected as training samples and the remainders,as testing samples.Results show that the prediction accuracy of SVM model is improved with the increase of training samples and prediction accuracy of the two SVM models are higher than that of BP neural network models.Therefore,support vector machine method is a new machine learning method with higher precision and better generalization performance than neural network method.It has very broad application prospects and promotion and application values in the practice of debris flow hazard assessment.

Abstract:When cultivated land is designated as basic farmland,the goals of land protection plan are mainly considered,while regional differences in resource endowments are usually neglected.With the help of spatial analysis technologies and previous studies on land suitability evaluation,this paper points out that the designation of basic farmland should be based on land suitability index and present situation of land use.By taking Siyang County as an example,basic farmland designated using the new method is 577.5 km2,about 84.8% of total cultivated land.The proportion of basic farmland in the north and the south of Siyang County is relatively high because its land suitability index is high.The proportion of basic farmland near Siyang County and main roads is relatively low because of high construction land demands.The result indicates that we should take regional differences in resource endowments into consideration while converting cultivated land into basic farmland,so as to coordinate the contradiction between land protection and economic growth.

Abstract:Accurate estimation of reaso nable grassland yield is an important scientific basis in determining the carrying capacity .To maintain ecological balance of grassland ,a reasonable arrangement of animal husbandry has important theoretical and practical significances .There are three main approaches to estimate grass production:field measurement , meteoro-simulation model , and remote sensing .A large number of survey data are used to construct a mathematical model.The model is used to estimate grass production and then compared with other models for its reliability and accuracy .At last , the modelis applied to estimating forage production

Abstract:The purpose of the study was to demonstrate the feasibility of bran to be the matrix of soilless-cultured lawn through measuring physiochemical indexes of matured bran and biological indexes of lawn.A three-level bran maturing experiment with four levels of fertilization was carried out.The biological indexes of ryegrass lawn were measured 30 days after seedling emergence.Results show that the physical and chemical indexes of matured bran meet the basic requirements of lawn cultivation and it can be used as a lawn matrix.The addition of sludge for maturing is more effective than the addition of sugar and check,which can significantly increase ryegrass growth rate.When the rate of seedling emergence is higher than 60%,the lawn is coiled.The study provides some basic data applied to soil and water conservation and slope protection.

Abstract:The principle and method of analytic hierarchy process(AHP)were applied to assess the sustainable development factors of converting farmland into forest/grassland in North Shaanxi Province.Twenty indexes are weighted,in which the first class indicator includes four factors,that is,ecology system,economic system,population system,and policy management system.Results showed that the factor of eco-efficiency was the greatest weight factor,being about 50% and the second one was economic development indicator,being about 30%.They matched the reality exactly.All of them lay the basis and foundation for the post-period plan in the region.

Abstract:Regional precipitation is an important environmental factor and has a great scientific value in the reasonable programming of regional water resources.In this paper,meteorological data of rainfall,wind direction,etc.from 1971 to 2004 were picked up in 14 observatory stations and 8 climate investigation stations.Geography information such as longitude,latitude of the station,sloping direction,and altitude were also included.Prevailing wind-direction effect index and altitude were introduced to reflect climate difference and terrain for precipitation interpolation.Precipitation simulation model in rainy season in the east of Dabie Mountains was built.Spatial precipitation distribution in the east of Dabie Mountains was simulated by using spatial analysis function of GIS for grid data.Simulated results show that in view of different regional characteristics,precipitation simulation precision can be improved by the addition of effective terrain and meteorological factors to participation in interpolation.The relative errors of spatial precipitation distribution simulation in each month and summer and rainy seasons in the east of Dabie Mountains are less than 10%.Precipitation on south and north slopes in the east of Dabie Mountains is characterized by obvious spatiotemporal variation.Mountainous disturbance as a boundary layer has obvious influence on precipitation.Seasonal variation of precipitation on south and north slopes is consistent with seasonal variation of atmospheric circulation.

Abstract:Evapotranspiration is mainly affected by energy,soil moisture content,and biological characteristics of plant.Based on the field experimental data for years,an empirical model to estimate the evapotranspiration of Populus tomentosa shelter belt from April to October in cropland of the Alaer irrigation area is established by the way of mathematical statistics method.Results show that the ratio of the evapotranspiration to water surface evaporation and the soil moisture content in root zone display the Logistic curve.The model uses routine meteorological and soil moisture data only,so it is convenient in calculation and valuable in utilization.

Abstract:The purpose of the study was to reduce the losses caused by flood and to prevent them in advance,by taking Laoshan District,Qingdao City as an object.Based on GIS components and the spatial analysis of GIS,we designed an evaluation model to develop flood risk evaluation system for Laoshan District,using factor set,judgment set,membership function,and weight set established by the method of fuzzy comprehensive evaluation.The system can produce assessment results automatically after user enters data,which is classed into high grade,slightly high grade,medium grade,slightly low grade,and low grade.The results obtained by the rating system are most in common with the actual results.Especially,Wanggezhuang street is in the highest grade in the area.With good flexibility and performance,the method of the system can be popularized to general crisis evaluation judge.

Abstract:Flood data sequences are characterized by randomness,nonlinear,uncertainty,and similarity.The characteristics are consistent with the study object of the fractal theory,so flood can be staged using fractal theory.Taking Xiangjiang River basin as an example,flood season of Xiangjiang River basin is staged through analyzing flood data sequences of Xiangtan staff gauge station,computing capacity dimension,and determining the number of flood season staged.The new method is then compared with the traditional method of flood season staged.It is revealed that the stages of Xiangjiang river basin determined by using fractal theory are consistent with those from traditional method,but the method using fractal theory is much more objective.It is feasible in flood season staged and needs to be discussed and applied further.

Abstract:Based on the assessment index system of eco-agricultural construction benefit at medium scale,the assessment index system of eco-agricultural construction benefit in Changwu County was established.The weights of indicators were estimated by analytic hierarchy process(AHP).According to the data and research achievements of the evolutionary process of agricultural eco-economic system from 1980 to 2008,the comprehensive benefit of Changwu County was assessed quantitatively.Results showed that the comprehensive benefit of eco-agricultural construction was raised from "inferior" in 1980s to "good" in 2008.Development of economical benefit is most obvious,while ecological benefit develops steadily.The comprehensive benefit has been increased significantly in recent years.In conclusion,the overall function of the agricultural system should be increased by improving agro-ecological environment and ecological benefit.

Abstract:The main problems and changing trends of water environment in Xinjiang Wei Autonomous Region,as well as their causes,are analyzed by Ridit analysis method and other qualitative and quantitative methods based on the water monitoring data and economical data from 2001-2006.Results show that water quality of rivers in Xinjiang is in slight pollution.Water pollution in the north is more serious than that in the south.Water quality of the rivers far from urban areas is better than that through urban construction areas.The changing trends of water quality of rivers are stable.Water qualities of lakes and reservoirs are in medium pollution.Water quality of lakes is better than that of reservoirs.The changing trends of the water qualities of lakes and reservoirs are stable.Water quality of drinking water sources are good basically and its changing trend is stable.Ground water quality in Urumqi is in the degree of Ⅳ—Ⅴ and its changing trend is stable.The main causes leading to the water problems in Xinjiang are the heavy industrial structure,rapid growth economy,weak urban infrastructure,heavy pollution in rural areas,and poor protection of drinking water sources.

Abstract:The data of COD_Mn,NH_3—N,TP,TN,Chla,and pH were collected at the 12 monitoring points in Caohu Lake.Then,the spatiotemporal characteristics of water environment and their causes were analyzed.Results showed that the trends of COD_Mn and TP in the lake were in a slight fluctuation from 1995 to 2007,but there were significant decreases in TN and NH_3—N.Chla had no obvious change except in 2003.Compared between the periods from 1995 to 1999 and from 2000 to 2007,the area of higher COD_Mn concentration was enlarged in the west lake from 2000 to 2007 and the area of TP was reduced in the west lake at the same period.The area of higher NH_3—N concentration migrated from the Paihe River inlet to Qiaonan area.TN and Chla concentrations in the west lake were higher than those in the east lake,but pH was high in Huailin in the east lake.In a word,water environment in the east lake was better than that in the west lake and water environment in the two lake areas has improved in recent years.The causes for the spatiotemporal characteristics of water environment in Chaohu Lake are possibly the point source pollution from industrialization,non-point source pollution from agriculture and living pollution from city,increased eutrophication by the steadily increased endogenous release,and a growth environment easy to induce water bloom and bad water environment.

Abstract:Agricultural production in Shandong Province exhibits an important status in China.However,the increasingly serious occurrence of agricultural pollution severely affects the advantage agricultural production and the environmental quality of its prominent origins.The main factors were analyzed in the 6 aspects of fertilizer,poultry and livestock manure,living sewage,straw,pesticide,and agricultural plastic film.Nitrogen and phosphorus loss from 2001 to 2006 was calculated.Results showed that the main causes for agricultural pollution in Shandong Province are the excessive input of agricultural chemicals and the excessive output of agricultural wastes,as well as their unreasonable utilization.Manure,fertilizer,and living sewage were the three main sources in terms of the contribution to nitrogen and phosphorus loss.In 2006,the three sources caused a total loss of 672 700 ton nitrogen and 135 000 ton phosphorus,among which,to Nitrogen loss load,manure,fertilizer,and living sewage accounted for 50.78%,41.99%,and 7.22% and to phosphorus loss load,80.30%,11.78%,and 7.93%,respectively.More attentions should be paid to the researches on high effective application techniques of agricultural chemicals and utilization techniques of agricultural wastes as to the prevention of agricultural pollution sources in Shandong Province.

Abstract:Yan'an City is the only pilotcity in the grain for green project in China .Since the project was implemented, the sustainable development of rural economy in Yan'an City has at tracted widespread at tention .In this study , analytic hierarchy process(AHP)is applied to evaluate the sustainable development of rural economy in the city .Results show that the grain for green project has promoted the sustainable development of rural economy in the city .The sustainable development degree for Yan'an City from 1998 to 2007 is between 0.5094 and 0.6051 .Although the level is in the general state of sustainable development , it is still in a rising trend.Sustainable state is gradually shifted from general state to a higher state .

Abstract:Owning to the unreasonable exploitation,the normal environmental system in Manasi River basin is disturbed and its conditions become worse,with ecological service functions declining.In order to recover the normal ecosystem,the beneficiary and the loser should be compensated.Base on the structure,functions,and location of the ecological system,the basin is divided into 3 eco-functional regions.After analyzing the problems of each functional region and understanding the principles,approaches,and standards of compensation,we present some advices and eco-functional mechanisms for these problems.

Abstract:Fragmentary system of resource value and distorted farmland resource price result in ignoring the latent expense of land resources that have ecological and social values during the farmland non-agricultural conversion.Based on this recognition,this paper analyzes the value loss of social eco-system and the spatial situation during farmland conversion in Jiangsu Province.Results show that the value loss of social eco-system is 9 932.202 million Yuan in Jiangsu Province from 2000 to 2007.Per unit value of farmland social eco-system in the north of the province is bigger than that in the south.

Abstract:In order to explore the impact of the technology adoption behavior of farmers to the different levels of agr-icultural technology, a logistic model of influencing factors for farmer willingness to participate in agricultural watersaving is established based on the investigated data of 392 farmers from the different levels of agricultural technology in the arid and semiarid area. Results show that in the environment of high level agr-itechnique diffusion, government support policies are the main factor to encourage farmers to adopt water-saving irrigation. In the environment of intermediate level agr-itechnique diffusion, the adoption of water-saving irrigation technology is easily influenced by the number of annual t raining and natural conditions in rural areas. In the environment of low level agr-itechnique dif fusion, water-saving irrigation technology is more vulnerable to the impacts of farmer. sacceptance of new technolo gies, natural conditions in ruralarea, and farmer s. riskaw areness. At last , some measures to raise the level of agricultural technology to a high level are suggested, such as intensifying government support policies, streng thening education and training, and improving regional information environment.

Abstract:As a kind of typical aquatic-terrestrial ecotone,riparian zone has very important ecological,economic,and social values,whereas landuse has a major impact on ecological environment of riparian zone.Exemplified with buffer zone around Baiguishan Reservoir in Pingdingshan City,an evaluation index system indicating the impacts of landuse on ecological environment was formed in view of landuse type.Remote sensing techniques were adopted to acquire landuse information,expert marking method was used for index quantification,and AHP method was adopted for index weight determination.Evaluation results show that landuse has a moderate negative influence on ecological environment of buffer zone around Baiguishan Reservoir.Impacts of landuse on ecological environment in different divisions of buffer zone are different.The order of the three divisions is No.1No.2No.3,among which division No.1 has a greater impact,division No.2 has a moderate impact,and division No.3 has a light impact.The landuse types having greater impacts on ecological environment in the buffer zone are the urban construction land,orchard and vegetable land,and forest and grassland,as well as industrial and mining lands.

Abstract:Great effects have been achieved since 1991 when the landslide and debris flow early-warning system in the control areas of siol and water loss in the upper reaches of the Yangtze River was established.Construction process and operation mode of the system are introduced.Effects of the system are evaluated according to economic,social,and ecological effects it brings.Economical effect is evaluated according to protection ratio and loss ratio of investment.To protection ratio,land protection ratio is 15.11 km2 per 104 yuan and resident life protection ratio is 40.0 persons per 104 yuan.Moreover,fixed assets protection ratio is from 40.0 to 93.3.To loss ratio of investment,economical loss ratio is 3.63 and casualty loss ratio is 5.69 persons per 104 yuan.Correlative evaluating data and instances show that the achieved effects of the system are remarkable and its construction and development should be further enhanced.

Abstract:On the background of the increasing contradiction between supplies and demands of water and land resources,water and land resource system coupling is studied for the optimal allocation of the regional resources.An allocation model of water and land resource system coupling is established and genetic algorithm is used to solve the multi-objective problem.In the calculation of the model established,inherent potential of the resource system is maximally considered so as to achieve the development goals of sustainable utilization of the resources.Finally,the Chanba ecological zone in Xi'an City is taken for an example to make an empirical solution and optimal results of water and land resource coupling are obtained.The study may provide a basis for the research on the allocation of water and land resource system coupling in the process of urbanization.

Abstract:Based on the conceptual model of growth drag and some relevant researches,a growth drag model to water and land resources in the development of urbanization is introduced.By taking Xi'an City as an example,the decline of levels due to restrictions of land and water resources is calculated and analyzed using the revised growth drag model and econometric theory.Results show that because of the constraints of water resources,urbanization rate may decline by 0.010875% annually.Because of the constraints of land resources,urbanization rate may decline by 0.004696% annually.Total growth drag is about 0.015571% and the role of water resources is greater.This is mainly due to the growth of land resources in Xi'an City,the intensive use of land and water resources,and a decline in capital elasticity.In view of the trend of change about the use of resources over time,however,the damping data fo Xi'an City may become greater in the future.

Abstract:A model of seepage analysis for heightening planning of a tailings filling dam is constructed by using ADINA,in which seepage field of the tailings filling dam is analyzed.The coefficient of material permeability of the tailings filling dam obtained from inverse analysis is greater than that from laboratory experiment.Seepage free surface from the model is higher than practically measured seepage free surface.The coefficient of material permeability obtained from inverse analysis is more reasonable because the environmental conditions of the tailings filling dam are taken into consideration.After the tailings filling dam is heightened,seepage free surface will become higher,so seepage-proofing equipment and drainage equipment should be added.If possible,surveying equipment for seepage free surface should be added as well.

Abstract:18 sampling areas of size 5 m×5 m were selected,of which 15 sampling areas were composed of Ostryopsis davidiana Decaisne vegetation community only.Soil shear strengths at the depths of 20,40,60,80,and 100 cm in the 18 plots were measured.3 bare lands of size 5 m×5 m were selected and soil compaction and the ratio of sectional root area were measured as well.The effect of soil shear strength in bare land was then removed from the soil sample in Ostryopsis davidiana Decaisne vegetation community.By calculation,the ratio of sectional root area was 1.014% and the corresponding shear strength was the maximum value of 0.134 6 kN/m2.Analyses indicated that the increased value of soil shear strength in the Ostryopsis davidiana Decaisne vegetation community rood system was positively correlated to the ratio of sectional root area.

Abstract:Based on the investigation of soil and water conservation monitoring in the development and construction projects of Shaanxi Province,the main monitoring contents are analyzed such as factors,status,and hazards of soil and water loss,as well as soil and water conservation measures and the control effects.Accordingly,a monitoring index system of soil and water conservation and its specific monitoring indexes are presented.The monitoring index system is composed of 4 forms,i.e.,monitoring indexes of dynamic change in soil and water loss,monitoring indexes of hazards by soil and water loss,monitoring indexes of soil and water conservation measures,and monitoring indexes of soil and water conservation benefits.The study may provide a technical support to the scientific and orderly works on soil and water conservation monitoring in the development and construction projects of Shaanxi Province.

Abstract:Constructing small eco-clean watershed is the main direction of soil and water conservation and water protection in future China.By taking Yongkang small eco-clean watershed as an example,a series of control measure projects are constructed,including ecological restoration,planting of soil and water conservation forest,sloping farmland management,runoff control,treatment of bare slope,and other measures like rural domestic wastewater treatment,control of agricultural pollution,improvement of rural living environment,and gully control,so as to form a measure system of small eco-clean watershed construction projects.Practical effects of the completed projects are analyzed and summarized.