Abstract:A field simulated rainfall experiment was designed to quantify effects of mulch cover on hillslope soil erosion and nutrient loss in the black soil region of the Northeast China.The experiment treatments included one fertilizer input(150 N and 75 P kg/hm²) and three mulch cover levels(bare land,2 and 4 kg/m² corn mulch cover).Simulated rainfalls were applied at a rate of 90 mm/h for 60 minutes on slopes of 5°.The plot size was 10 m long and 1 m wide.The results show that when corn mulch cover was 2 kg/m²,runoff decreased by 87% and the soil loss reduced by 99.86%,respectively,comparing to the bare land.For 4 kg/m² of corn mulch cover,no runoff occurred.Under the 2 kg/m² mulch cover treatment,NO^-₃—N and pO^3-₄—P concentrations in runoff were 5.52 and 4.25 times higher than them from the bare land,but the total losses of NO^-₃—N and pO^3-₄—P in runoff were similar.NO^-₃—N and pO^3-₄—P in eroded sediment from the lowly covered plot were 4.38 and 2.93 times respectively greater than them from the bare land;but the total losses of NO^-₃—N and pO^3-₄—P in eroded sediment from mulch cover treatment reduced by 99.3% and 99.6%,respectively.Therefore,the proper corn mulch cover is important for protecting soil quality and reducing agricultural non-point pollution.

Abstract:The effects of CO₂ concentration and nitrogen supply on the contents of soil organic carbon and total nitrogen in Calamagrostis angustifolia wetlands of Sanjiang Plain was investigated.An experiment was carried out with treatments differed in nitrogen supplies(0,5 and 15 g/m2) and CO₂ levels(350 and 700 μmol/mol) with OTC(open-top chamber) equipments.The results show that with additional nitrogen,the soil organic carbon varied but not significantly with increases of 0.5%~1.8%.The elevated CO₂ decreased the contents of soil total nitrogen.The average reduction of NH⁺₄—N due to the elevated CO₂ elevation was 8.2%,8.9% and 9.7%,for the three nitrogen levels,respectively.The contents of NO^-₃—N decreased similarly under higher CO₂ levels.Both NH⁺₄—N and NO^-₃—N decreased to a greater degree with the high N supply(15 g/m2).Soil available N was the key factor in affecting the response of the plants to elevated CO₂.

Abstract:Based on the observations of rainfall events and recorded soil erosion data on the plots-which was established particularly for typical soils of southern China,in the Ecological Experiment Station of Red Soil(EESRS),Yingtan City,Jiangxi Province,the relationship between sediment yield and rainfall factors was explored for the time period from 1997 to 2003.The results show that under the relationship between sediment yield and surface runoff could be described by a power function,while the relationship between sediment yield and rainfall volume could be described by a polynomial function.Owing to the distinct soil and land use types applied among the plots,the equations describing sediment yield and rainfall factors varied significantly.

Abstract:Linear regression method,wavelet analysis and sequential Mann—Kendall test analysis were applied to characterize runoff and sediment time series collected at Jiangqiao hydrological station of Nunkiang River from 1955—2006.The results show that during 1955—1966,a period with little human activities,sediment yields remained relatively stable and no correlation between sediment and rainfall was found significant.In contrast,strong sediment fluctuations and a close correlation between sediment and rainfall were identified in 1967—2006,mainly owing to reinforced human disturbances.Linear regression method was adopted quantify the effects of rainfall and human activity on runoff and sediment.Comparing with base period,total runoff volume of the research area reduced by 7.90×109 m³ per year,within which 3.770×109 m³,4.130×109 m³ were affected by human activity and rainfall,respectively.During 1967—2006,the sediment reduced at a rate of 3.329×105 t per year given the decreased rainfall;however,human activity resulted in a sediment increase of 3.899×105 t per year.In summary,human disturbance,rather than rainfall variations,was the driving factor for the decline of runoff and the increment of sediment in the research area during the study period.

Abstract:Fractal theory was applied to analyze grain size distribution of the sediment of Weihe River in Xianyang City.The fractal scaleless range and the fractal dimension of grain size distribution were determined.In the non-scaled range,the correlation coefficients(R2) of 53 samples were all higher than 0.95 and the average fractal dimension was 2.12,which shows that the distribution of sediment particle size exhibited good fractal characteristics.The fractal dimension as a new parameter of sediment grain size analysis was compared with traditional granularity index such as mean-diameter(Φ),standard deviation(σ),skewness and kurtosis.The correlation coefficients of fractal dimension of sediment grain size with mean diameter,standard deviation,kurtosis and skewness are 0.807,0.707,0.675,and 0.112,respectively,implying fractal dimension correlated significantly positively with mean diameter,standard deviation and kurtosis,but insignificantly positively with skewness.

Abstract:Luohui irrigation area,located in the east of Guan-zhong plains,exhibits distinct salt accumulation processes in different regions.This study aimed at providing scientific basis for the improvement of ecological environment of the Luohuiqu irrigation district by exploring the variations of groundwater salinity.Periodical variations of groundwater level and electrical conductivity has been analyzed at well 76# using Morlet analysis.It is shown that the two variables were significantly closely correlated.The period of groundwater level on small scale was similar to that of electrical conductivity,but approximately two times longer on large scale,with a reverse phase.The electrical conductivity background of the groundwater was relatively high,because of the large amount of soluble salt layers found in this area.Due to indirect water supply from precipitation,electrical conductivity values fluctuated with groundwater levels within a certain range.

Abstract:A Dynamax sap flow measuring system consisted of heat balance sensors was used to continuously monitor sap flows of corn(Zea mays) on Horqin sandy land,Northeastern China.The photosynthetic active radiation,air temperature,relative humidity and wind velocity were recorded synchronously by an automatic weather recording system.Based on the manual records of weather conditions,four most representative weather conditions were gathered up to analyze the relationship between sap flow,water consumption and meteorological factors.The results showed that the diurnal variations and affecting factors of sap flows differed with weather conditions.However,the photosynthetically active radiation was always the dominant factor affecting the sap flow.The diurnal sap flow changes of corn showed board peaks or single-peaked curves in sunny days,multiple-peaked curves in cloudy days,and single-peaked or irregular multiple-peaked curves in windy day and rainy day.The diurnal variations of sap flows resulted from comprehensive effects of multiple meteorological factors.The water consumption for an individual corn plant was the highest in sunny days,followed by windy days,cloudy days,and rainy days,with means of 588,401,399,and 305 g/h,respectively.

Abstract:Compared with the control of bare surface,the effects of plastic-film mulching,corn-straw-only mulching,and film-plus-straw mulching on the soil temperature,soil moisture and the growth of tomato were monitored in Hetao irrigation area.The results showed that the plastic-film mulching increased the soil temperature,and corn-straw mulching and film-plus-straw mulching reduced the soil temperature.In comparison,corn-straw-only mulching exerted stronger effects than film-plus-straw mulching.All the mulching treatments resulted in increases of soil moisture within 0—50 cm in the early stage of tomato growth,while the plastic-film mulching was the best.The yields of tomato with plastic-film mulching and film-plus-straw mulching were 222.61% and 17.04% higher than the control,respectively.However,the yield with corn-straw mulching was 3.06% lower than the control.The water use efficiency under plastic-film mulching and film-plus-straw mulching were 93.83% and 5.90% higher than the control,respectively.Similarly,water use efficiency of corn-straw-only mulching was 19.29% lower than the control.The results indicated that the plastic-film mulching was suitable,and the corn-straw mulching was undesirable in sowing time for tomato production in Hetao irrigation area.

Abstract:The exploitation of the Shenfu-Dongsheng coalfield caused a large amount of disturbed lands,leading to anthropogenic soil and water loss.In this study,we investigated hydrodynamic features of the water flows through carrying out scouring experiments in the field.The results indicate that the relationship between the velocity of flow and the discharge could be well described by a power function.The flow velocities increased firstly from the upper section to the middle and then decreased from the middle section to the bottom section on the slope.The state of the flow was turbulent flow,suggested by a power function between the Reynolds number and the discharge.The values of the Froude number varied between 0.59~0.88,resulting in subcritical flows.The resistance coefficients increased with the slope gradients.The relationship between the flow shear stress and the discharge followed a power function,same as the relationship between the flow powers and discharges.They both changed great with the slope changing great.

Abstract:In order to provide references for adjustments of agricultural structures and crop arrangements,which aim to improve farmers' income within a commodity economy,optimal combinations of crop rotation are needed for agricultural development in Guanzhong plain.According to field test data,the economic value,land equivalent ratio(LRE),biological yield,economic coefficient and the effects of rotation on soil nutrients were analyzed in different rotation systems.The crops tested included food crops of wheat(Triticum aestivum) and corn(Zea mays),and vegetables of garlic(Allium sativum),pepper(Capsicum),eggplant(Solanum melongena) and celery(Apium graveolens),which are commonly found in the plain.The results show that the terms of economic benefits and land production efficiency,the rotation system of wheat-maize was the worst one while the vegetables—vegetable rotation systems of garlic—pepper,garlic—eggplant,garlic—celery were the superior ones.From the ecological point of view focusing on biological yield and net organic yield,the value of wheat—maize was lower than the values of the vegetable—vegetable systems of garlic—pepper,garlic—eggplant,and garlic—celery,and was higher than the values of the crop—vegetable systems of wheat—pepper,wheat—eggplant,and wheat—celery.In the terms of effects on soil available nutrients and soil respiration rates,the crop—vegetable systems were better than the vegetable—vegetable rotation systems and the traditional crop rotation systems.Considering the values,geographic conditions and economic environments,the crop—vegetable rotation systems were suitable for the plain.As for the trials of this study,the rotation modes of wheat—pepper and wheat—eggplant were promising with a comprehensive consideration.

Abstract:C,N and P dynamics in above ground parts of Calamogrostis angustifola,which was growing on different water zones with various water regimes,were studied by field investigation.The results show that total carbon(TC) fluctuated with time in all zones and were higher in the zones inundated all year long.Total nitrogen(TN) and total phosphorus(TP) decreased with time and the increase of soil water.C,N,and P of the leaves were higher than that of stems and vaginas.The ratio of C and N differed in zones with various inundation periods,and the ratio of C and P increased with the growth of the plant and soil water contents.The ratio of N and P generally increased with soil water contents,while increased and then decreased in the growing season.The quality of Calamogrostis angustifola decreased with increasing soil water.At the early growing stage,the growth of the plant was limited by N under all water conditions,while at the later growing stage,P was the limiting factor at the zone inundated all year long and N remained the stressing factor in the other zones.

Abstract:Based on field survey on the 161 grids with areas of 625 m² in Jianfengling of Hainan Province,the water storage,water-holding capacity,water-holding rate and water absorption rate of forest litter were studied in different tropical rainforests(including primary forest,selectively logged forest and clear-cut forest).The results show that in primary forest,selectively logged forest and clear-cut forest,the litter storage was 6.42,6.29 and 6.66 t/hm²,and the max water-holding capacity was 9.55,10.49 and 11.17 t/hm²,respectively.Clear-cut forest has the highest max water-holding rate of 169.2%,followed by selectively logged forest(168.0%),and primary forest(155.6%).The max water-holding rates in the three forests differed significantly as indicated by the Kruskal—Wallis H test.The water-holding capacity and water-holding rate of litter in all the forests increased logarithmically with soaking time(W=alnt+b).While,the water absorption rates of litter reduced followed equation W=at-b as soaking time increased.

Abstract:In the semi-arid hilly region of South Ningxia Hui Autonomous Region,three-year,seven-year,eleven-year,and nineteen-year old alfalfa fields and seven-year old alfalfa fields at uphill,middle slope,and downhill were taken as study objects.The dynamics of the dried soil layer(0—5 m) and soil moisture and nutrients were analyzed.The results show that both slope position and plant age affected soil moisture contents.The average moisture content of 0—5 m soil profile on the uphill alfalfa field was 6.34%,which was substantially lower than that on middle slope and downhill fields.The average moisture contents in 0—5 m soil profile decreased on the alfalfa fields as in order of three-year,seven-year,nineteen-year,and eleven-year,and soil drying index(SDI) decreased as in order of uphill,middle slope,downhill and three-year,seven-year,nineteen-year,and eleven-year.The dying degree declined as soil depth increased.After the alfalfa aged,soil moisture content could recover but took a long time.On all the alfalfa fields in this study,the average content of soil organic matter,total N,available N,total P,available P,and available K all increased in the fields from uphill to downhill.As the soil depth increased,the soil organic matter,total N,available N,total P,and available P decreased.As the age of alfalfa increased,the soil organic matter,total N,total P,available P,and available K exhibited a declining trend,but the available N increased first and then decreased with the age of alfalfa in the field.When alfalfa field was very old,the soil organic matter and total N began to accumulate but was still at a relatively low level.

Abstract:Wuli Lake of Taihu Lake region is a typical hyper-eutrophic,shallow lake in China,situated near the Wuxi City in Jiangsu Province.Since January 2004,a large-scale macrophyte restoration experiment(105 m²) was carried out in southwestern Wuli Lake using a large enclosure.The results show that from August 2004 to July 2005 mean concentrations of PO3-4—P and NH+4—N of submerged area and macrophyte area inside the enclosure were 54.6% and 46.7%,17.1% and 13.8%,lower than those of outside enclosure,respectively,implying markedly improved water quality inside the enclosure.Phosphate releasing simulation from the cores collected from different areas in enclosure and outside enclosure was conducted in the laboratory.The resulted showed that the mean phosphorus release rates of the sediment from the submerged area and macrophyte area inside the enclosure were 0.23±0.42 mg/(m²·d) and-0.38±0.65 mg/(m²·d),respectively,contrasting to 1.13±1.31 mg/(m²·d) outside the enclosure.Overall,rehabilitated macrophyte not only decreased the concentrations of nitrogen and phosphorus,but also controlled the phosphorus release rate of sediments.

Abstract:In order to study phytoremediation of Tamarix ramosissima on saline-alkali soil and its effective range.Total salt and ionic contents of saline-alkali soils and characteristics of nutrient partition were analyzed based on field comparative test with saline-uncultivated land as CK.The results show that Tamarix increased nutrient contents of the saline-alkali soils,but decreased pH,total salt and ionic contents.Compared with CK,soil organic matter(SOM),available N,and available P at surface(0—20 cm) increased 30.5%,49.8% and 51.4%,respectively,and at sub-layer(20—50 cm) increased 78.8%,21.3% and 25.0%,respectively.The pH value was 0.3 units lower than CK at surface layer(0—20 cm),but was 0.4 units higher at sub-layers(20—50 cm).The desalination rate at surface layer and sub-layer were 86.4% and 88.2%,respectively,while ESP decreased 75.4% and 53.8%,respectively.Meanwhile,Tamarix exhibited selective absorption for Na+ and Cl-,with a significant higher reduction amplitude than other ions,such as Ca2+,Mg2+,K+ and SO2-4.An optimizing region with "lower total salt,lower pH and higher SOM" was formed in a layer of 0—25 cm depth within 15 cm to Tamarix.An reasonable Tamarix arrangement that could fully realize its biological and non-biological functions will be the key to improve physical and chemical properties of saline-alkali soils for sustainable development.

Abstract:In order to investigate the variations of root characteristics in terms of anti-bending with changes of root diameter and slope position,a total number of 36 Robinia pseudoacacia L.trees on a steep rocky slope were selected and root samples were collected.Anti-bending forces of the root samples were measured using an electronic universal testing machine.The results show that the relationship between anti-bending capability and slope position was significant.Root anti-bending capability decreased from upper-slope position to the down-slope position.For roots in the upper and the lower slope positions,the relationship between bending strength and root diameter can be described by a power function,and root tolerance of bending increased with root diameter.As for the roots collected in the mid-slope position,there was no significant relationship between bending tolerance and root diameter.Root flexural modulus decreased as root diameter increased,which can also be described by a power function.Flexural modulus decreased from the upper slope to the down slope for roots with diameters greater than 8 mm.Maximum anti-bending forces and fracture deflections of the roots did not differ significantly among the three slope positions.The former decreased from the upper slope towards the down slope,while the latter increased from the upper to down slope.In conclusion,the roots in the upper slope had the strongest bending resistance,which contributed most to the slope stability

Abstract:An in-depth understanding of the succession mechanism of natural vegetation is critical and badly needed.The responses of cultivable soil microorganisms to the vegetation succession in Ziwuling,the Loess Plateau were investigated with the method of "converting spatial series into temporal series".The results demonstrate that the gross amount of microbes,bacteria and fungi in the soil increased in lands as the order of abandoned land→grassland→shrub land→Betula platyphylla forest→Quercus liaot.ungensis forest→Quercus wutaishanica—Betula platyphylla forest(F>0.01,p<0.01).The amount of actinomyces fluctuated and relatively higher values were found in shrub land and Q.liaotungensis forest.The Shannon—Wiener value as a comprehensive index of soil microorganisms fluctuated as well,influenced by the variations of fungi population.As the succession progressed,the population sizes of ammonifying and nitrifying bacteria increased significantly(F>0.01,p<0.01).The nitrogen-fixing bacteria increased slightly in general but not significantly(F>0.05,p<0.05),with the largest population in Q.liaotungensis—B.platyphylla forest.Comparatively,the highest numbers of cellulose-decomposing microorganisms were found in Q.liaotungensis forest and Q.liaotungensis—B.platyphylla forest.As indicated,the vegetation succession has significant effects on the variations of the three soil microbial groups tested as well as on the main functional groups,promoting the proliferations of soil microorganisms.The changing of soil microorganism diversity was not always in the same pace as of vegetation succession;vegetation types determined the diversity,which varied with vegetation compositions.

Abstract:Soil water characteristic curves were determined using a pressure-membrane extraction apparatus for the soils collected on five different plantations,i.e.,pure fir forest(Cunninghamia lanceolata),fir and pine(Pinus massoniana) mixed forest,and three other mixed broad-leaved forest(Schima superba×Cinnamomum camphora×Lithocarpus glaber×Liquidambar formsana,Schima superba×Lithocarpus glaber and Cunninghamia lanceolata×Pinus massoniana×Schima superb) in Simian Mountain of Chongqing City.The results show that the empirical equation(θ=aS^-b) proposed Gardner(1970) described well the relationship between soil moisture contents and soil water suctions for all the soils from the five forests with coefficients of determination greater than 0.99.In terms of the fitting parameter a values,the soil water retention capability of the five forest soils as in order from high to low were Cunninghamia lanceolata×Pinus massoniana×Schima superba(a=0.328),Schima superba×Cinnamomum camphora×Lithocarpus glaber×Liquidambar formsana(a=0.248),Cunninghamia lanceolata(a=0.225),Schima superba×Lithocarpus glaber(a=0.218),and Cunninghamia lanceolata×Pinus massoniana(a=0.206),respectively.According to the regression equations,the soil water suction upper limit of soil available water was approximately 0.03 MPa.The specific water capacity indicated that soil available water decreased substantially when the suction is greater than 0.15 MPa,which implies that 0.15 MPa might be the critical value for differentiation of readily available water and slowly available water.According to the a×b values(the product of fitting parameter a and b,which equals to the specific water capacity when the soil suction S=1.00×105 Pa) and readily available water contents,although no obvious trend has been identified in the variations of soil water supply capability for different soil layers of five plantations,the soil water supply capability of five plantations in order from high to low were as followed: Schima superba×Cinnamomum camphora×Lithocarpus glaber×Liquidambar formsana(ab=0.065,readily available water 11.704)Cunninghamia lanceolata(ab=0.062,readily available water 10.677)Schima superba×Lithocarpus glaber(ab=0.058,readily available water 10.485)Cunninghamia lanceolata×Pinus massoniana×Schima superba(ab=0.058,readily available water 10.003)Cunninghamia lanceolata×Pinus massoniana(ab=0.056,readily available water 9.980).

Abstract:For physiochemical analysis,soil samples were collected three variously vegetated slopes in Zhongzhuang watershed of Pengyang County,which is a typical geomorphologic unit of the mountainous regions of the Southern Ningxia Autonomous Region.The results show that both sea-buckthorn woodland and artificial pasture had lower soil moisture,soil bulk density and soil porosity than naturally enclosed land.Compared with the artificial pasture,the sea-buckthorn woodland had lower averages of soil moisture within 0—200 cm,and relatively higher soil bulk density and lower porosity in the layer of 0—60 cm.Within 0—60 cm,the natural land had the highest total nitrogen,readily available nitrogen and soil organic matter,followed by the pasture and the woodland.The woodland,natural land and pasture had respectively high,intermediate and low total potassium,readily available potassium and readily available phosphorus.As for total phosphorus,the woodland had the highest average content and the natural land had the lowest.All the differences were found statistically significant.

Abstract:Three runoff plots of bare land,waste grassland and shrub land were established in Yangou watershed of Yan'an City.Based on observations of total rainfall,rainfall duration,runoff depth,sediment yield,infiltration rate in individual rainfall events,the erosion characteristics of each plot were investigated using the statistic package of SAS.The results indicate that regardless of rainfall intensity,both runoff and sediment yields decreased,and correspondingly the infiltration rate increased in the three plots as listed in order.Runoff were closely correlated with rainfall.Sediment yields increased with total rainfall,especially in the bare-land plot.Similarly,the infiltration rates increased with total rainfall amounts,but decreased significantly in rainfalls with high intensity.The sediment yields correlated well with the runoff.However,a quadratic function performed better in describing the relationship between the sediment yield and runoff of the grassland.

Abstract:Based on RUSLE model,quantitative monitoring of soil erosion was carries out in the Xihe River Basin using HJ-1A/1B data,DEM,TRMM and other data.Soil erosion estimation from the monitoring was compared to the classification using the multi-factor method.In addition,further validation for monitoring results was performed using remote sensing survey of soil erosion of Liaoning Province published in 2005.The comparison results show that CCD data produced by HJ-1A/1B was adequate for soil erosion monitoring and RUSLE model can be applied well to monitor soil erosion.Total erosion area in 2009 reduced significantly comparing with that in 2005.Soil erosion distributed mainly in northwest and southeast mountainous areas of the study site,and the opencast coalmines within the "coal city" of Fuxin City resulted in severe or even stronger soil erosion.

Abstract:In the suburb of Beijing City,a bare section of the river bank was selected at the Liuli River to investigate and monitor the positive effects of soil bioengineering techniques on river ecological restoration in local areas.The river bank is marked by diverse types of soil erosion including splash erosion,sheet erosion,gully erosion and seepage erosion.Several soil engineering measures such as stem cuttings,brush mattress,root burying and fascine were deployed as near-natural restoration of the river bank.The growth characteristics and bank stabilization effects of Salix matsudana were investigated respectively in 1,4,5 and 13 months after the deployment.The results indicate that Salix matsudana achieved a high survival rate,and the average height of the new shoot and the average root diameter reached 116.9 cm and 0.85 cm respectively.The growth of Salix matsudana varied considerably among the four engineering measures.Within one month after the deployment,brush mattress treatment showed the highest growth vigor,followed in order by the treatments of root burying,and then fascine.In the other three investigation times,Salix matsudana in the root-burying treatment showed the best growing condition and the stem-cutting treatment was the worst.The growth characteristics in terms of root diameter and new-shoot height exhibited exactly the same trend.The application of soil bioengineering techniques efficiently recovered the plants on the riverbank and increased largely the biodiversity at the same time.This paper also summarized the precautions for the riverbank management.

Abstract:Rainfall erosivity and its characteristics were studied by analyzing rainfalls and soil erosion data recorded within the period of 1997—2003 at the ecological experiment station of red soil(EESRS),which is located in Yingtan area,Jiangxi Province.The results indicate that for the studying area,the events of rainfalls and erosive rainfalls occurred from March to August in each year.According to the method of R "EI30" value,the rainfall erosivity was 7 231.8,12 051.9,3 722.3,6 864.2,4 520.5,6 299.1 and 5 580.9 MJ·mm/(hm2·h·a) for the years from 1997 to 2003,respectively.The rainfall erosivity varied considerably not only in years,but also in months.Finally,the simple and easy algorithm for rainfall erosivity calculation was proposed based on the analysis of the relationship between the rainfall volume and sediment yield during the 244 events of erosive rainfall within the seven years.Based on the validation,the simple algorithm performed better than the traditional algorithm of EI30,particularly for the widespread purpli-udic cambosols.However,the accuracy of the simple algorithm remained almost the same as the traditional algorithm in the soils of ali-udic argosols and typic argi-udic ferrosols.The results indicate that the new simple algorithm might be suitable for wide use in the study area.

Abstract:The distribution of rocky desertification in different types of land use was identified on SPOT imagery(2.5 m resolution) with 3S technology.The results indicate that,rocky desertification(over mild degree of desertification) occurred in parts of cultivated lands,shrub lands,sparse woodlands and/or grasslands.According to the habitat characteristics and social economic development of the upstream,midstream,and downstream areas in Shiqiao catchment,engineering and biological measures of desertification control were suggested as followed:(1) Practicing intercropping and rotation of tree—grass,tree—crop,crop—grass in sloped farmland as breakthrough points of ecological construction under high population pressure;(2) Optimizing water resource network of water pumps,head tanks and channels as the kernel;(3) Developing a suburban hybrid industry of agriculture,forestry and animal husbandry as a ecological system to promote rural economic growth in future.Finally,water and soil loss,rocky desertification will be controlled with soil erosion reduction of 32%,income increase of 533 yuan per capita,and sustainable ecology,economy and society.

Abstract:A number of saline soil improvement materials were tested in meadow saline soils of the Hexi Corridor in terms of soil physiochemical properties,corn yield and economic effects.The results show that composite A2B3C3D1E2(aluminum sulfate 800 g,sulfur 900 g,gypsum 4 500 g,furfural residue 800 g,and polyethylene glycol 60 g) is the best saline-alkali soil improvement materials with consideration of all factors.The application amount of each improvement material was positively correlated with total porosity,aggregate composition,natural water storage,and the desalting rate,and was negatively correlated bulk density,pH,EC,and total salt content.With the application rates of 0.61,1.22,1.85 t/hm²,the seedling growth,botanical characteristics and yield of corn were improved correspondingly.With application rates greater than 1.85 t/hm²,the efficiency of saline improvement materials decreased.The marginal production value,marginal profit,production increase,profit,and the ratio of profit to input reached the maximum values with the application rate of 1.85 t/hm².Saline soil improvement material suitable dosage of 1.83 t/hm²,the corn yield forecast 6.29 t/hm²,and field trial results was consistent with the 4th treatment.

Abstract:Exponential smoothing based on time series is one of the methods widely used in predicting,but is rarely applied in the dynamic simulation and prediction of soil moisture.In this paper,the simple exponential smoothing was used to simulate and predict daily soil moisture and soil water storage capacity of an artificial locust forest in the loess region of Western Shanxi Province,between June 1st and September 30th,2009.The results show that soil water moisture and soil water storage capacity were simulated and predicted with a reasonable accuracy level.Observations of seven different layers(0—150 cm) indicated that the prediction accuracy of soil moisture increased with soil depth.The maximum error of the predictions within the layer of 100—150 cm was less than five percent,and the most accurate prediction(with an average error of 0.1 %) were found in the layer of 120—150 cm.Compared with the predicted and measured values,it was found that rainfall,evaporation and evapotranspiration,surface runoff,plant uptake and other factors may affect the artificial locust forest soil water moisture and soil water storage capacity up to the depth of 120 cm.

Abstract:Based on single factor experiments,the adsorption of Cr⁶⁺ on fulvic acid(FA) from the soil was optimized by a combination design of quadratic regression and orthogonal rotation.The quadratic orthogonal regression model of potential removal rate of Cr⁶⁺(y) as function of four variables including FA density(x1),pH(x2),reaction time(x3) and reaction temperature(x4) was established.As implied by the model,the rate(y) reaches its peak of 78.27%with FA density of 2.11 g/L,pH value of 5.65,reaction time of 8.8 h and reaction temperature of 23.8 ℃.This model prediction was also consistently confirmed by experiment results.

Abstract:According to Chaos Theory,the time series of NH₃—N pollution index at Minjiang Bridge in Le-shan City,Sichuan Province was reconstructed through the phase spaces.The reconstruction parameters were determined by the application of mutual information and Cao's method,and the characteristic indices including correlation dimension,Maximal Lyapunov index and Kolmogorov entropy were calculated accordingly.All the results indicate that a nonlinear chaotic characteristic can be clearly identified in the time series of NH₃—N pollution index of Minjiang Bridge,which might result from the non-linear chaotic dynamic system evolution.The research laid the basic foundation for further study on the complexity and evolutionary law of the time series of NH₃—N pollution index.It also offered the decision-making support for monitoring and protection of water quality in the middle and upper reaches of Minjiang River.

Abstract:Based on long-term water quality monitoring data,the indices of water quality identification were applied to evaluate the water quality of Yuncheng Section of the Fenhe River during the period of 2005—2009.The surface water quality of monitoring sites at Xinjiang Station and Hejin Bridge was further classified based on the evaluation.The evaluation results show that COD,BOD5,and ammonia nitrogen exceeded the standard rates substantially,and ammonia nitrogen was the most severe pollution indicator.The results also show that the water quality did not meet the corresponding functional requirements of the water environment,nor did it meet the standards for surface water quality.Water quality controls on COD,BOD5,and ammonia nitrogen should be carried out more strictly.The findings of this work will provide basis for planning,management and protection of Yuncheng City's surface water resources.

Abstract:This paper discussed the methods to create hydrologically correct DEM(Hc—DEM) at medium resolutions for Jiangxi Province using 1∶250 000 topographic maps and ANUDEM software.The quality of the DEMs was further assessed.The data preprocessing,the determination of the key parameters and others for Hc—DEM creation were addressed carefully.In addition,contour line overlay analysis,random checkpoint analysis and stream network analysis were adopted in evaluation of Hc—DEM quality.The results show that based on the topographic information of the existing digital topographic maps(including contours,spot heights,and streamlines) and the application of ANUDEM software,high-quality DEM representing the correct relationship between the stream networks and the geomorphology could be created.The quality level of constructed DEMs reached the USGS standards.The created DEM had the resolution of 50 m,iteration number of 30 and the second roughness coefficient of 0.5.

Abstract:The health of forests affects directly global ecological stability and sustainable development.The prediction of forest health is an important means for people to understand forest health status.Based on the selected indicators of forest health,a model has been constructed to predict the health of Jiufeng National Forest Park using a three-layer BP neural network.The results show that the adoption of neural network in forest ecosystem health forecasting was reasonable and reliable.Some important conclusions and recommendations have also been given for constructing a precise and stable prediction model.

Abstract:Focusing on the problems in quantitative evaluation of geological disasters,we investigated and discussed the risk assessment system of geologic disasters by using the tendency analysis method in GIS program.The risk assessment of Jiangxian County in Shanxi Province was taken as the study case.The results of this method agreed well with the actual geological survey information,which implies that the tendency analysis is applicable for risk assessment.This paper provides a new theoretical method for geological disaster zoning.

Abstract:Many parameters were recognized as affecting factors of slope runoff,such as precipitation volume,precipitation intensity and vegetation.Runoff plots were established in a small watershed,Wangdonggou of Changwu County,Shaanxi Province.The method of grey rational degree was applied to analyze the effects of the precipitation and vegetation on slope runoff and erosion by comparing influencing factors.The results indicate precipitation had the highest rational degree with slope runoff and erosion.The parameters contributing to slope runoff in the descending order were rainfall volume,maximum rainfall intensity,rain intensity,and vegetation coverage.The parameters contributing to erosion in the descending order of rational degree were rainfall,rain intensity,maximum rainfall intensity,and vegetation coverage.When the coverage was lower than 25%,runoff volume was similar;when the coverage was over 25%,runoff volume reduced with increasing coverage.When the coverage was lower than 50%,the total erosion decreased rapidly with the increasing coverage.However,the erosion-reducing efficiency of the vegetation significantly decreased when the coverage was higher than 50%.

Abstract:Soil erosion of soil dump during highway construction is one of the most important parts of road erosion,and the terrain features of the dump determines its erosion characteristics.The evaluation and prediction of the dump shape is therefore the prerequisite for precise soil erosion estimation of the soil dumps.An approach was established to estimate the shapes of soil dumps according to the characteristics of highway excavation and soil piling,and it was then tested with the data obtained on Changde—Zhangjiajie Highway.At last,the regional differences of dump shapes were compared between southwest mountainous areas and southeast of China.The results show that the method well predicted the height of waste dumps,with a mean relative error of 37.67% and correlation coefficient of 0.94.The waste soil production during highway construction in the mountainous areas was 1.5 times more than that in the hilly regions.The waste dumps of the mountainous areas were mainly located in gullies and valleys,with relatively larger volumes and occupancy areas and lower heights.

Abstract:The hydrodynamic process of soil water erosion was systemically simulated in the study by artificial precipitation experiments with treatments of two slopes(20° and 25°) and four rainfall intensities.The relationship between sediment yield and its impact factors was also studied using gray correlation analysis.The results show that rainfall intensity had the highest correlation coefficient with surface erosion sediment yield.Stream power was the factor with the second highest coefficient.Surface erosion sediment yield was therefore described by rainfall intensity and stream power with established regression equation.

Abstract:Desertification,as a prominent environmental problem in southwest karst rocky region,is a problem particularly for the regional economic development and ecological construction,challenging the comprehensively sustainable development in this region.According to domestic and foreign literature,a desertification model was developed based on analysis of the concept and characteristics of desertification.The feedback mechanisms between desertification and background environment were discussed.The model divided risk pressure into four categories,i.e.,disturbance,accumulation,succession,and fragmentation.The risk factors of desertification were then analyzed and classified based on the pressure—state—response model.An assessment system for desertification risk was establishment for karst rocky areas.

Abstract:Chenier Islands is an important geological phenomenon occurred during the continent building process since approximately 5 000~6 000 years ago on the west and northwest of Bohai Bay.As a natural protection,the Chenier in Wudi coast of the Yellow River Delta played an important role in securing human life and property.In this article,species composition and plant diversity in the area of Dakouhe River and Wangzi Island were investigated.The results show that 32 species of plants,beloging to 13 families,and 29 genera were found in the area.The aridisphytes,mesophytes and plants of high salt tolerance were the dominant species.Along the section from seaside,shell ridge to landside,the species richness and biodiversity index significantly increased,as well as distributional evenness index,Simpson index,and Shannon—Wiener index.Due to human disturbance,the species in Dakouhe River were far less than that in Wangzi Island area.However,the evenness index decreased from east to west in both areas.In temporal scale,the most abundant species were found in August owing to sufficient rainfall and high temperature.

Abstract:The trait gradient analysis as a hot topic in ecological research provides an improved approach to explain community assembly and ecosystem structure and functions.Twenty-four dominant species in Yanhe Basin were investigated by recording their heights in their communities.The heights were then decomposed into α and β components to characterize the variations of plant heights within and among communities.The results show that the height variations of the dominant species were owing more to the interactions between species within the community than to the influences of the environment.The herbage communities had higher α than β values,similar to the whole basin,implying a dominant influence from the interaction among species.While in shrub and tree community,the β value was generally higher than α value,suggesting stronger impacts from the environment gradient changes.The findings of this study are of great significance to understand the role of environmental factors and biological interactions in the formation of plant communities,providing bases for revealing changes of vegetation patterns and guides for vegetation restoration.

Abstract:The productivity of farmlands in Wugong County was assessed and classified based on "county arable land management information system",information collected in the second national soil survey,and analysis results from the balanced fertilization on soil testing.The results show that the total cultivated area of Wugong County is 32 923.77 hm²,accounting for 83.74% of the total land area.The areas of the 1st,2nd,3rd,4th,5th and 6th grade cultivated land were 4 869.23,11 969.56,9 338.52,4 700.82,1 725.81 and 319.82 hm²,respectively;which constitute of 14.7%,36.36%,28.36%,14.28%,5.24% and 0.97% of the total area of the cultivated land,respectively.Based on evaluation results,recommendations were proposed specifically for arable lands with various grades.

Abstract:The region of Aksu is the major cultivation area of Xinjiang Fuji apple in Southern Xinjiang region.Six trace elements in Fuji apple were determined using atomic absorption to compare the effects of different water-nitrogen treatments on trace element contents of Fuji apple.The results show that increased nitrogen improved contents of Ca,Mg,and Zn under moderate water condition.Moderate irrigation and fertilizer maintained high Fe level.Excessive or insufficient irrigation and fertilizer undermined the accumulation of mineral Fe in apple fruits.The contents Cu and Mn related positively to the application amounts of nitrogen.

Abstract:Linzhi area of Tibet is one of the most dangerous regions threatened by debris flows in China.Under the influence of global warming,the melting rate of glacier has accelerated in this area,leading to frequent initiations of glacier-melting debris flows,which is severely hazardous.Since the middle of July,2009,the authors had carried out systematic investigations regarding approximately thirty debris flow gullies in counties of Linzhi,Milin,Bomi and Chayu in Linzhi area.Based on analysis of the twenty typical debris flow gullies and related historic documents,debris flows were divided into four classes according to initial water conditions,namely,rainfall-induced debris flow,glacier-rainfall-induced debris flow,avalanche-induced debris flow,and lake-outburst-induced debris flow.The initiation conditions were analyzed regarding landform,soil source,water source and air temperature.Specific advices based on the analysis were recommended for disaster prevention.

Abstract:Land ecological security evaluation is of essential significance in realizing security and sustainability of regional land ecosystem.Liaocheng City of Shandong Province was taken as the study area and a system consisting of 20 indices from the natural,social and economic factors influencing land ecological security has been established based on comprehensively consideration of land use status.Based on the variances and coefficients of variance,the weight and the comprehensive scores were determined and calculated for land ecological security.Classification and evaluation of land ecological security of the eight counties(cities) of Liaocheng City were then carried out according to weighted sum method.The results show that,the security status of Dongchangfu District and Gaotang County were classified as "good grade",while the other six counties(cities) were labeled "alarming grade".Problems of land ecological security in the study area were analyzed,which could provide some reference value for the sustainable utilization of land resources.

Abstract:With a shallow epicenter and extraordinary intensity,numerous secondary mountain hazards,including landslides and debris-flows,were triggered by the "8·30" earthquake occurred at Huili County,Sichuan Province.Nuozha gully,one of the tributary of Jinsha River,located in the southernmost of Huili County.The gully experienced a large number of rock-falls,landslides and collapsed slopes induced by the earthquake,which offered sufficient loose materials for the debris-flow.Furthermore,the right branch of the gully has a very large catchment area,which provides the energy and water source for possible outburst of debris-flow.Based on historic documents and field scouting,the downward and headwater erosion of Nuozha Gully,enhanced by downward erosion of Jinsha River,were the leading factors for reduced slope front resistance,resulting in unstable slopes and increasing failures in the upstream.The risks and trends of geohazards were assessed for the gully.Geotechnical engineering,including check dams,debris dam,as well as ecological measures like forest planting,were recommended for controlling debris-flow of Nuozha gully.

Abstract:In recent years,the society and economy had been developed substantially along with exploding population.Under the policies of restoring ecological environment and improving fruit industry,land-use structure underwent drastic and profound changes.Supported by the software of ENVI 4.7 and ArcGIS 9.2,land-use changes in terms of changed areas,land-use regional variations and the matrix of transferring probability were calculated and analyzed using artificial supervised classification based on 2000 and 2006 TM remote sensing images and other data.The results show that land use structure of Luochuan County had changed greatly during the six-year time span.The orchard and construction land changed substantially and the newly developed area increased rapidly,with a recent depletion of grassland.The area of orchard nearly doubled and a considerable amount of cultivated land was transferred to construction land.The area of forest increased gradually.Regional land use variations and land-use transferring differed in the extent and scale.The increase of orchard come mainly from grassland and forest land,while woodland was mainly converted from grassland.A noteworthy amount of orchard and farmland was converted to each other.

Abstract:The dynamics of land use and land cover in Tongchuan City,Shaanxi Province were analyzed based on TM remote sensing images of 1987 and 2002.Together with remote sensing(RS) and geographic information system technology,information regarding land use types was obtained using the supervised classification method.The characteristics of quantity and spatial variations of land use were further analyzed based on collected information.The results indicate that the percentage of vegetated land(woods,shrubbery,and grassland) increased from 54.52% in 1987 to 64.46% in 2002,approximately an increase of 10 %,implying significant achievements resulted from the project of Grain-to-Green project.Furthermore,the total area of residential land,transferred mainly from cultivated field,almost doubled during the period,showing a serious land use problem of cultivated field depletion owing to urban expansion.

Abstract:Water resource problems in Taihu basin became serious with the development of society and economy.In order to evaluate the water ecosystem services of Taihu basin and to provide a theoretical basis for watershed management,this study divided water resources of Taihu basin into seven districts based on the statistics data,land-use data and hydrological information,and then evaluated and analyzed the water ecosystem services and their spatial variability.The results show that the water supply volume of Taihu basin was 3.70×1010 m³/a,aquatic product yield was 6 681.180 t/a,transportation capacity of passenger and freight travel were 4.604×108 person/(km·a) and 2.90×1011 t/(km·a),respectively,water storage capacity was 4.53×109 m³/a,flood control capacity was 7.69×109 m³/a,carbon fixation and oxygen release rates were 4.28×106 t/a and 1.14×107 t/a,respectively,water purification capacity was 6.30×109 t/a,and sand transport and land reclamation rates were 1.22×106 t/a and 189.851 hm²/a,respectively.The total value of water ecosystem services was 9.10×1010 yuan/a.The order of various services in terms of value was as following,tourismtransportationwater storage and flood controlwater purificationcarbon sequensation and oxygen releasewater supplyaquatic productsand transport and land reclamation.The average ecosystem service value per unit area of Taihu basin was 19.22 yuan/(m²·a).The order of various districts in terms of average service value was as following,PuxiWuchengWest ZhejiangHangjiahuHuxiYangchengTaihu.

Abstract:Based on ecological footprint(EF) model,EF distributions over time and space were determined in Huaihai Economic Zone from 1986 to 2008,and the eco-system sustainability was assessed on the twenty city members of the Zone.The study shows that regional EF per capital had increased rapidly by 5.74% per year.In 2008,the four highest EFs was observed respectively on cities of Laiwu(9.143 6 hm²),Zaozhuang(6.340 4 hm²),Huaibei(6.185 2 hm²),and Jining(5.004 9 hm²),and the four lowest EFs respectively on Fuyang(1.038 5 hm²),Zhoukou(1.122 1 hm²),Suqian(1.209 7 hm²),and Kaifeng(1.319 5 hm²).For all cities,the largest EF was as approximately nine times as that of the smallest.Among the six types of land,energy land was the most important factor that contributed to EF differences.Total ecological capacity(EC) per capital decreased slightly,and ECs of all cities ranged between 0.4~0.7 hm².Ecological surplus was found in 1986,1987 and 1988.After 1989,ecological deficits(EDs) become increasingly larger as 1.692 1 hm² in 2008,with an annual increasing rate of 29.08%.Therefore,the EFs had been over demanded substantially by the ECs,which were continuously consuming the natural capital stocks to compensate EDs,threatening ecological security of the economic system.According to ecological sustainability index(I^ES),more than half of the cities had I^ES lower than the critical value for the state of "moderately non-sustainable",within which cities of Laiwu,Zaozhuang,Huaibei,Jining,Taian,Xuzhou and Rizhao were classified as "strongly non-sustainable cities".Finally,at a perspective of regional scientific development,countermeasures and suggestions have been addressed to promote sustainable development in all cities of Huaihai Economic zone.

Abstract:For further understanding of growth dynamics and reasonable utilization of grassland,an experiment was carried out in shrub-grass vegetation in degradation hilly area of Wufeng Mountain,Ji'nan City of Shandong Province.Above-ground biomass,species diversity,and reasonable use were addressed.Results showed that above-ground biomass of the grassland reached its maximum value in August.Zoysia japonica,Arundinella anomala,Themeda japonica,and Arthraxon hispidus were the dominant grassland species,and the importance values of Zoysia japonica and Arundinella anomala were higher than the other grassland species.Species diversity indices of Pielon,Simpson and Shannon—Wiener were increased with growth time.In 2009,the protective index of gramineae was 151.87 g/m²,and the protective indices of Zoysia japonica,Arundinella anomala,Themeda japonica and Arthraxon hispidus were 76.34,59.95,23.37 and 46.60 g/m²,respectively.

Abstract:The major objective of this study was to characterize the root system of the 1～3 year old seedlings of Caragana microphylla,an important shrub species in Longxi hilly region of the Loess Plateau,China.Root morphology,growth and development,distribution and nodule characteristics were determined after excavation.The results show that the growth rate of the major root of Caragana microphylla was much greater than that of the stem.The ratio of root to shoot ranged from four to six.The lateral roots were found mainly on the 5～15 cm section of the major root.The radicles of Caragana microphylla in average elongated 5 cm upward,implying a reasonable sowing depth of 3 cm.The nodules concentrated mainly on the major root and the first-division lateral roots in the 10—30 cm soil layer.The fast-growing,well-developed root system and nodules provided the plant with superior drought resistance and ecological functions of improving soil quality and conserving soil and water.Compared with spring sowing,fall sowing agreed to local light,heat,and water resources better and should be promoted to a higher level.

Abstract:Ecological compensation standard constitutes the core of payment for watershed ecosystem,on which tremendous amount of researches have been done with debating perspectives.Based on the "Assessment Standard for Forest Ecosystem Services(LY/T1721-2008)" published by the Department of Forestry,a case study was conducted on the forest ecosystem of Qiupu River in the base year of 2007.The results show that total value of the forest ecosystem services was about 5.47×108 yuan.Based on the externality principle,ecological compensation standards should be established according to spatial variations of ecosystem services.The upper limit of ecological compensation should not be higher than the total value of forest ecosystem services,while the lower limit should be set as the value of the leading function(e.g,water resources conservation and soil conservation),which was 2.16 ×108 yuan for the study site.

Abstract:Bridge engineering activities are referred to as a series of activities in order to achieve some specific purposes,i.e.,the interactions by human beings with the peripheral ecosystem in the process of bridge design,construction and operative maintenance.This paper analyzed the effects of the bridge engineering activities on ecosystem processes.From physical,chemical,biological and social perspectives,the ecological effects of bridge engineering activities were addressed.A philosophy of ecologization was then proposed for bridge engineering activities.Furthermore,ecologization strategies were discussed specifically for the design,construction and operative maintenance phases in bridge engineering activities.In summary,the purposes of bridge projects should be not only to meet social needs,but also to satisfy the requirements for the healthy and sustainable ecosystem.

Abstract:In order to investigate on the effects of returning crop residual as mulch in addition to film mulching,field plot experiments were deployed in sloped lands of Jianping County,Chaoyang City,Liaoning Province.Five levels of residual returning(0,400,800,1 200 and 1 600 kg/hm²) were compared in terms of soil moisture retention and maize yield.The results show that the residual returning treatment of 800 kg/hm² exhibited the best effect on soil moisture retention.The yields of the lands with residual returning of 400,800,1 200 and 1 600 kg/hm² were 5 069.20,5 781.46,5 462.25 and 5 407.46 kg/hm²,with increases of 18.62%,35.28%,27.81% and 26.53%,respectively,in comparison of the control.The treatment of 800 kg/hm² also displayed the best influences on maize growth in comparison of the others,as indicated by the statistically significant difference.