Abstract:To understand the effects of erosion on soil respiration(R_s), we analyzed temporal variations of R_s on the slope lands and its relationship with soil temperature and moisture under artificial stimulated erosion conditions(top soils removed at the depths of 0, 5, 10 cm, referred to as E₀, E₅ and E₁₀)with a dynamic closed chamber. Two type of lands in which the fertility levels differed distinctly were chosen to deploy the experiments. The results indicate that with similar temperature and rainfall, the rates of R_s were affected sig-nificantly by erosion and the affecting degree was related closely to the fertility level of the land. Comparing to the control(original soil without removal of top soil), the R_s rates of the soils with the erosion level of E₅ decreased by 32%and 14%in the fertile and poor soils, respectively. The rainfall stimulated the R_s rates and amplified the effects of erosion on the R_s rates. Soil moisture contents were closely correlated with the R_s rates, and conversely, the soil temperature was not. Soil moisture was the main controlling factor responsi-ble for the variations of soil respiration rates during water erosion events. The results suggested that the effects of erosion on R_s rates should be considered in understanding and estimating carbon loss in the loess hilly region. Soil erosion may alter the carbon balance through dynamic changes of R_s in these ecosystems, which could have important negative consequences for ecosystem functions and sustainability.

Abstract:The hydraulic characteristics and flow energy consumption of runoff on steep slope woodland were studied under accelerated erosion condition with simulated rainfalls. The results show that the natural soil surface had a significantly effect on reducing flow velocity, which remained very slow as 0.05 to 0.09 m/s. The flow velocity increased under manmade accelerated erosion. Furthermore, the increasing amplitude was greater on the lower slope position than the upper one. The Reynolds number R_e of the runoff on natural soil surface of the woodland was 160.8, which can be recognized as laminar flow. Under manmade accelerated erosion, the flow shifted to a transition state between laminar and turbulent flow condition. Compared with natural soil surface, the Froude number F_r of the middle and lower slope position with litter removal in-creased by 114.9%~245.1% and 322.2%~1 012.9%, and the friction coefficient f increased by 5.2%~90.6% and 42.6%~270.3%, respectively. The flow velocity on the bottom and mid-lower slope sections were rapid with F_r＞l, and slow on the upper and mid-upper slop sections with F_r＜1. The treatment of till-age increased F_r and f by 181.6G~72.3G and 41.3%~66.80% on the bottom, mid-lower and mid-upper slope sections. In the upper section, F_r decreased by 67.3~ while f increased by 8 times. The potential en-ergy of the surface flow was greater than kinetic energy, the kinetic energy level of the flow was low in early stage of simulation rainfall and then increased and finally stabilized over the experiment time. Compared with the natural soil surface, the energy consumption of the slope surface increased in all the treatments of forest litter removal, cutting above ground parts and tillage. The intensity of soil erosion was closely related to en-ergy consumption of the slope surface.

Abstract:Based on determination of soil water retention curves and field moisture capacity of intact soil sam-ples of Loess and Paleosols in Luochuan County, Shaanxi Province, the study analyzed the physical soil prop-erties including soil moisture storage, holding capacity and effective moisture content. The results indicate that the water retention curves of soil samples could be described well with Van Genuchten model with the high R2 values(over 0.99). The water holding capacity of the loess samples were higher than that of the Pal-eosol samples in the range of 0 to 30 kPa, suggesting that loess performs better in water supply and storage. With increasing suction values, water supply and storage reduced with larger amplitude in low suction range and smaller amplitude in high suction range. Loess showed higher available water content, saturated water content and field holding capacity, and lower permanent wilting point than paleosol.

Abstract:Based on the land use maps of Northwest Guizhou Province, which were interpreted from Landsat images of 1974, 1992 and 2008, we analyzed and simulated the status of soil erosion before and after the land use/cover change(LUCC) and the soil erosion effect of main types of LUCC with incorporation of the revised universal soil loss equation(RUSLE). The results show that the structure of LUCC had changed significantly in Northwest Guizhou Province. The areas of shrub and cultivated land varied dramatically, showing oppo-site change trends from 1974 to 2008. With great increment of cultivated land and decrement of shrub, the soil erosion modulus increased from 29.55 t/(hm²~a) to 37.76 t/(hm²~a) in the area from 1974 to 1992. The area of cultivated land decreased and the area of shrub and forest increased from 1992 to 2008, resulting a significant reduction in soil erosion(30.39 t/(hm²~a) in 2008]. As cultivated land contributes most to soil erosion, the massive conversion from shrub to cultivated land was the main cause of severe soil erosion in 1992, while the extensive conversion from cultivated land to shrub and forest reduced soil erosion greatly in 2008. Even recently, the conversion from shrub to cultivated land caused a substantial amount of soil ero-sion. The related agencies should strengthen the management of shrub land.

Abstract:Using spatiotemporal substitution method, we constructed a sequence which was formed by natural grassland and Caragana microphylla stands of 7(young), 12(intermediately aged) and 27(old) years old. In addition, we measured and analyzed the variations of the soil nutrients including organic matter, total nitro-gen, alkali-hydro nitrogen, and available phosphorus. The results show that： (1) The soil organic matter contents within 0-200 cm displayed an ascending order of the cover as meadows〈 young stand〈intermedi-ately aged stand.old stand; the increasing trend of organic matter was more significant in the deeper layers. (2) The grassland soil had lower total nitrogen contents than the soil of young Caragana microphylla stand. The total nitrogen contents in the soils decreased with the increase of the forests age, as the biggest differ-ence was found between the young and intermediately aged stands. Alkali-hydro nitrogen showed the exactly same trend as total nitrogen. (3) The available phosphorus content in the whole soil profile is： aged forests ~young forests〈middle-aged forests〈meadows. (4) The spatial variability of all the variables in the three differently aged Caragana microphylla forests was not significant in the rows and between the rows. The degree of correlation was found high between organic matter and total nitrogen, and low between alkali-hydro nitrogen and available phosphorus.

Abstract:Biological soil crusts are widely distributed in the desert as an important biological factor to stabi-lize the sand dunes and promote restoration of sandy ecosystem. Landsat remote sensing images of Mu Us Desert in 1989, 2002 and 2006 were used to extract spatial distribution of biological soil crusts and land de-sertification based on the biological soil crust index and NDVI threshold. Furthermore, the relationship be-tween biological soil crusts and land desertification was discussed. The results show that the areas covered by biological crusts accounted for 54.77%, 55.72% and 64.29% of the total area in the three study years, re-spectively, indicating biological soil crusts in the study area increased continuously. In addition, the connec-tivity among crust patches was enhanced, and the crust stability was further strengthened. In contrast, the degree of land desertification was gradually weakened during the study period, as the composite index of land desertification dropped to 2.65 in 2006 from 3.24 in 1989. Biological soil crusts distributed most widely(over 70%) in the lands experienced moderate and severe desertification. However, the area of biological soil crusts continued to decline in extremely severely desertified lands, accounting for 19. 40%, 5. 76% and 2.80 % of the total area of the extremely severely desertified land in the three study years, respectively. The number of biological soil crusts was increasing in extremely severe desertification land, indicated by the ratio of 19.40%, 33.18% and 45.21% in the three study years, respectively.

Abstract:With indoor experiment and field test, soil physical and chemical properties, soil disintegration rate and related influential factors of sloping land were determined. The formula calculation method of EPIC (ero-sion productivity impact calculator) was applied to investigate the erodibility factor K of the soil in sloping lands in northeastern upland region of China. The results indicate that soil bulk density increased in an as-cending order of soil depth as 0-5 cm＜20-25 cm＜40-45 cm. The soil of lower slope had smaller bulk density than that of upper slope. Similarly, the soil from gentle slope(7°) had smaller bulk density than that from steeper slope(10°). The organic matter contents showed an exactly opposite trend to bulk density. The median diameter of grain sizes did not show clear trend. The soil disintegration rates gradually increased with soil depth and correlated closely with soil bulk densities and organic matter contents., soil disintegration rate decreased with increase of organic matter content and decrease of soil bulk density. The soil from upper slope often had higher soil disintegration rate than that from lower slope, and the soil from gentle slope(7°) had smaller soil disintegration rate than that from steeper slope(10°). The calculated soil erodibility K varied be-tween 0.20 -0.40, indicating weak anti-erodibility. Therefore, water and soil conservation should be strengthened in the research area.

Abstract:Soil samples were collected at depth of 0-20 cm from a number of continuous cropping cotton fields across the Aler reclamation area of the upper reaches of the Tarim River. Five soil enzymatic activities and seven soil physieochemical properties were analyzed and their relationships were investigated using path analysis. The results showed that the enzymatic and physicochemical properties differed significantly between the continuous cropping cotton fields of various ages. Path analysis showed that soil enzymatic activities were mainly affected by total nitrogen in the soil and were significantly negatively correlated with soil pH value. The other factors such as soil organic matter, available P, available K and soil moisture indirectly influenced the enzymatic activities. Soil bulk density was found irrelevant with enzymatic activities.

Abstract:Numerous landslides occurred owing to the Wenchuan earthquake, leading to the accumulation of loose solid materials on valleys and slopes that trigger debris flows. The debris flows induced by rainfalls oc-curred frequently due to the presence of the wide-grade-unconsolidated soil. The loose soils that were dis-turbed intensively during the earthquake and mixed with rainfall after the earthquake became highly unstable and resulted in debris flows easily under storm rainfalls. It was found through the experiments of the infiltra-tion and erosion that the rate of the infiltration of the post-earthquake, mixed-grain-sized, unconsolidated soil was 1.5~6.0 times those of the similar soils in Jiangjia Gully, and resulting in the loss of finer particles in the soil and eventually the destruction of soil structure. The results of anti-scourability experiments show that the anti-scourability of the unconsolidated soil was weak due to the intensive disturbance it experienced, resulting in disintegration of soil agreggates and the soil was then eroded and transported away by surface runoff. The frequent occurrence of debris flows might be attributed to the strong rainfall along with the un-consolidated state of the soil. This phenomenon could keep occurring until the soil structure return to the o-riginal status before the earthquake. The critical rainfall for debris flow initiation may also change during this period.

Abstract:To elucidate soil and water conservation benefits of Phyllostachys nigra, simulated rainfalls were carried out in both Phyllostachys nigra forest and slope farmland, and the average sediment concentration and contents of nitrogen and phosphorus were determined. The resulted show that in Phyllostachys nigra forest, the runoff coefficient was 0. 096, with average sediment concentration of 0.26 ~, average content of nitrogen of 0. 152 rag/L, and average content of phosphorus of 0. 453 mg/L. In contrast, slope farmland had a runoff coefficient of 0. 299, with average sediment concentration of 0.99%, nitrogen content of 0. 198 6 mg/L, and phosphorus content of 0. 530 4 mg/L. The findings implies that Phyllostachys nigra forest ex-hibited clearly better benefits in regard to water and soil conservation than slope farmland.

Abstract:To understand pollutant purification effects of riparian buffer, field experiments with simulated farmland fertilization were conducted on riparian buffer strips of grass and planted forest, respectively. The surface runoff water and seeped water were collected and analyzed for total phosphorus(TP), total nitrogen (TN), ammonia nitrogen(NH₄-N)and suspended solid matter. The results show that the grass riparian buffer were significant better than the planted forest riparian buffer in terms of phosphorus removal in sur-face runoff water, while both of the buffer strips were similar in terms of nitrogen interception. Planted for-est showed similar efficiency for the interception of TN, TP and NH₄-N in both surface runoff and seeped underground water. The grass riparian buffer was superior to the artificial forest in terms of removing sus-pended solid matter. As expected, more pollutants were removed with wider riparian buffer. Human dis-turbances might be the main reason of weak pollutant removing ability of artificial forest riparian buffer. Finally, this study provided some practical suggestions for riparian buffer management.

Abstract:The bryophytes found in an abandoned Carlin gold mine of Xingyi City, Guizhou Province were in-vestigated in this study. According to field survey and identification of the bryophyte specimens, seven taxa in six genera of four families were found. Pottiaceae and Bryaceae were the dominant families and no Hepati-cae and Anthocerotae was identified. The life-forms of the bryophyte were mainly short turfs(85.71%) and the others were wefts(14.29%). The dominant bryophytes are Barbula rigidula (Hedw.) Mild., Bryum blindii B. S. G. , Trichostomu brachydontium Bruch. and Brachythecium perminusculum C. Muell. Of these species, the biomass range from 3.00 to 52.40 g/m², with formed soil varying from 217.50 to 3 695. 80 g/m², water holding capacity from 35.10 to 684.30 g/m², and saturated water absorption ratio from 1 170.00% to 3 637.00%. These results indicate that the bryophyte crust found in the mine had great ability to absorb and reserve water and played an important role in soil formation, rock desertification control and ecological environment renovation in karst areas.

Abstract:The quantity of ecological use of water was determined using experimental methods in the four dominant mountain forests in Beijing area during the growing season of the year 2010. The ecological use of water Platycladus, Pinus tabulaeformis, Robinia pseudoacacia, and Quercus variabilis were 376.15, 335.28, 258.90 and 374.94 mm, respectively. Vegetation transpiration was the major water use in total eco-logical use of water. Among the four forests, the effective precipitation in Robinia pseudoacacia was able to offset the water use as evapotranspiration, and was even able to add water into the soil as water storage, while the effective precipitations in the other three forests met only approximately 75 % of the water needs as evapotranspiration and 55 % of the total ecological use of water. Therefore, Robinia pseudoacacia forest was recommended for afforesting efforts in the areas with low precipitation.

Abstract:Based on the daily precipitation data of 16 selected meteorological stations over 1960-2010 in Sichuan Basin, this papaer analyzed the spatio-temporal distribution characteristics of annual mean precipita-tion days and different levels precipitation days by applying multiple analysis methods. The results indicated as follows. (1) The precipitation days occurring in Sichuan Basin showed a decreasing tendency, which star-ted since the 1990s and continued to now. (2) The decreasing of precipitation days of Sichuan Basin was a mutation phenomenon, which began from 1994. (3) The distribution of the annual mean precipitation days mainly showed that the more in west and south, while the less in east and north. (4) The precipitation days in west and north area of Sichuan Basin decreased rapidly. This decreasing tendency might be a result from the global warming. The regional distribution of precipitation days changed a lot with different levels. The increasing tendency of rainstorm days in northeast made more possibilities of geological disasters compared than ever before.

Abstract:This study investigated water-holding characteristics of Pinus tabulaeformis and Larix princpis forest litter found in Mulan-Weichang National forest farm. The results show that in the Pinus tabulaefor-mis and Larix princpis forests, the litter was as thick as 6.1 and 4.0 cm, with total water holding capacity of 33.93 and 43.16 t/hm², absorbed water contents of 268.10 g and 157.54 g(measured after 24 h immer-sion), and effective interception capacity of 30.07 and 57.56 t/hm², respectively. The litters of Pinus tabu-laeformis and Larix princpis showed similar water-holding capacity, water absorption rate and soaking time. Overall, the relationship between litter water-holding capacity and soaking time was described well with a logarithmic curve, and that between the water absorption rate and soaking time was fitted well with a power function. The water absorption rate was fastest in the initial 0-4 h, decreased gradually in 4-8 h after immersion, and the water content reached its maximum water-holding capacity after 10 h.

Abstract:In order to evaluate the influences of land-cover changes on surface runoff and sediment yield, two different land-cover data (1985,2001) in Xixi watershed of Jinjiang Basin were applied to the distributed SWAT(soil and water assessment tool) model. Quantitative results were obtained separately for the whole basin and subbasins. The results show that the effects of land-cover change was little to the runoff yield, while was significant to the sediment yield on the whole basin. Land-cover changes in sub-basins indicated that forest was the most important land use type for decreasing the runoff and sediment yield, orchard is the second, and followed by farmland and grassland. On the contrary, construction land contributed most for the increase of runoff and sediment yield.

Abstract:The temporal variability of soil water and its dynamics in Populus euphratica growth period in Minqin Oasis was investigated using geostatistics. The results show that the soil water content ranged be-tween 0. 85% ~ 4. 80% in the study area. The soil water contents increased with soil depth in both Shuangcike and Suwu Towns, while increased first and then decreased with the depth in Jiahe Town. The surface soil water content reached the lowest value in August. The soil water content in the growing season of the natural Populus euphratica forests varied considerably; the soil water content was higher in the spring, intermediate in autumn, and lower in summer. The variation efficient in general indicated a middle or strong variability in soil water content. However, the variation efficient of surface soil water content was greater than the others. The soil water content was less under Populus euphratica trees with greater diame-ters, which mainly related to the tree-age and root system. Overall, the soil water contents exhibited inter-mediate spatial correlation, and the variograms model for Suwu Town had the highest fitting coefficient.

Abstract:With Kenjian 5 Rice as experimental materials, the effects of water supply during the stage of before-head-ing on filling dynamics and yield of rice in cold regions were studied with pots under rainproof shelter. Water dynam-ics in the pots were monitored by examining soil water potential(SWP) using negative pressure soil moisture tensi-ometers. The results indicate that intermittent irrigation at SWP between -8~-10 kPa increased economic yield of Kenjian 5 Rice significantly, along with increases of average growth rate(G) and maximum growth rate(Gmax) of the superior grains and inferior grains and decreases of G and Gmax of the middle grains. The in-dex I values of superior grains and middle grains were improved, despite those of the middle grains. The growing active days(D) were shortened for the superior grains, while elongated for the inferior grains and middle grains. The weight per 1 000 grains(W-~axa) was increased for all the three grades of the rice grains. On the contrary, with unremitting irrigation at SWP between -18~-20 kPa and-28~-30 kPa during the stage of before-heading, economic yield of Kenjiandao 5 were significantly reduced, indicating by increased and Gmax values for the superior grains and decreased G and Gmax values for the middle grains and inferior grains, and raised I values, shortened D and increased W a for the grains of all the three grades.

Abstract:Based on daily and annual precipitation recorded at twenty-six meteorological stations in Qinghai Province from 1960 to 2009, regression analysis, inverse distance weighted method and Mann-Kendall method were employed to analyze the spatial and temporal variability in extreme precipitation events. The re-suits indicated that extreme precipitation days, annual maximum 1 d precipitation, annual maximum consecu-tive 5 d precipitation, very heavy precipitation days and daily rainfall intensity showed increasing trends in the recent 50 years, and only the extreme precipitation days were significant at the 0.05 level. The spatial change of precipitation extreme events in the study area showed that extreme precipitation days, annual max-imum 1 d precipitation, annual maximum consecutive 5 d precipitation, very heavy precipitation days and dai-ly rainfall intensity in Qilian Mountains had statistically increasing trends while they increased or decreased insignificantly in eastern region. In addition, it was also found that abrupt changes presented in precipitation extreme events at the 0.05 level. At the same time, there were significant correlations between annual total precipitation and different precipitation indices.

Abstract:Based on the meteorological and historical data of the past 50 years in Northern Shanxi Province, the influence of ENSO(E1 Nino-Southern Oscillation)events on the climate of Northern Shanxi Province was studied. The results show that both annual total precipitation and annual average temperature decreased at the years of ENSO warming events(E1 Nino events) comparing to the normal years. In the areas of Datong, Suzhou, and Qizhou City, annual total precipitation decreased for 46.83, 46.44, and 80.96 ram, and annual average temperature were reduced for 0.03, 0. 17, and 0.22℃, respectively. Similarly, both annual total precipitation and annual average temperature were lower, but less intensively, at the years of ENSO cold events(La Nina events) than the normal years. The annual total precipitation was 21.27, 26.32, and 25.30 mm lower, and annual average temperature was 0.03, 0.18, and 0.04℃ lower, respectively in the three re-gions. The annual average temperature of the sudy area changed in a direction opposite to that of the Loess Plateau in the years of E1 Nino events. The influence of ENSO warming events on the temperature represen-ted an ascending trend as in the order of regions： Datong City＜Shuozhou City＜Xinzhou City, as the lati-tudes of the areas decreased. The ENSO warming events imposed a similar effect on annual total precipitati-on, increasing the probability of the occurrence of draught disasters and harming the industrial and agricul-tural productions in study area.

Abstract:Climate factors including precipitation and temperature have significant effects on agricultural pro-duction. Traditional statistics, EOF analysis and wavelet analysis were applied to analyze the characteristics of periodic variations and spatial distribution of precipitation and temperature in this region based on data col-lected at the 12 weather stations in Weihe River basin during 1957-2009. The results show that： (1) The precipitation and temperature in the basin is affected by larger scale weather systems. The abnormity of pre-cipitation and temperature in Weihe River basin were simultaneous, and the abnormity of precipitation and temperature differed between south and north, and in the east and west. (2) Morlet wavelet transform indi-cated that the major periods for precipitation was about 30 years or more, while the main periods for annual mean temperature and mean maximum temperature were about 29 years or more.

Abstract:Based on observed temperature and precipitation data since 1961 in Southern Shanxi Province, the trend and periodic changes of temperature and precipitation in the area, as well as the effects of the E1 Nino/La Nina(E1 Nino/Southern Oscillation, ENSO) events on the temperature, precipitation, droughts, and floods were analyzed using wavelet analysis. The results show that during the past sixty years, the annual temperature of the area increased at a rate of 0.34℃/10 a, while the annual precipitation was decreasing at a rate of 23.4 mm/10 a. The wavelet analysis on the periodic changes indicate that the periods of annual tem-perature in the area were approximately 3, 8, 20, and 25 years and that of annual precipitation were about 3 years and 7 years. Annual mean temperature in the area ascended and annual precipitation decreased signifi-cantly in El Nino years, while showed opposite trends in La Nina years. Draughts occur more often in E1 Nino years, while more floods were recorded in La Nina years. Draughts and floods mainly occur in the con-tinuous E1 Nino years and La Nina years, respectively.

Abstract:Based on the meteorological and historical data in Yulin area of Shaanxi Province from 1961 to pres-ent, statistical analysis was conducted. The objectives of this study were： (1) Examine the relationship among precipitation, temperature, natural disaster events, and the ENSO(E1 Nino/Southern Oscillation) events. (2) Reveal the correlation between ENSO events and the climate of Yulin area. (3) Identify the peri-odicity of the precipitation and temperature changes. The results show that since 1954, the climate was war-ming significantly in Yulin area, with an annual temperature increasing rate of 0. 025℃ per year. However, the annual total precipitation decreased at rate of 1. 740 mm per year. In E1 Nino years, the temperature was O. 12℃ higher than that in normal years, and in La Nina years, the annual average temperature remained same to that in normal years. E1 Nino event lowered annual total precipitation approximately 8 mm than the normal years, while La Nina events did approximately 3 ram. The temperature and precipitation of the area changed at a short period of 3 years and a long period of 20 years. ENSO events was prone to cause high tem-perature and drought disasters, and ENSO warming events caused more meteorological disasters than ENSO cold events in the study area according to statistical analysis.

Abstract:Based on environmental economic theories and methods, we calculated the erosion-induced economic loss with different land-use structures in our study area over time and space. We also analyzed the dynamics of erosion-induced economic loss and the relationship between erosion-induced economics loss and land-use structure. The results show that the total economic loss resulted from soil erosion reached 9.82×109 , 9.94×109 and 8.80×109 Yuan in 1988, 2000 and 2007, respectively. The loss of nutrient contributed most to the total economic loss from soil erosion, accounting for 87. 44%, 88. 29% and 88. 02% in the three years, respectively. Among the different land-use types, the highest total economic loss by erosion was found in arable land. Grass land had higher economic loss per unit area than the other land use types. Meanwhile forest land was the lowest in terms of total loss and loss per unit area. The economic loss by soil erosion demonstrated spatial heterogeneity, Yunyang and Kaixian County had the highest total loss, and Changshou County had the lowest. Yunyang, Wulong and Kaixian County had the highest loss per unit area, where measures should be taken in the future to prevent soil erosion. Yiling district had the lowest loss per unit area.

Abstract:Ecological management was investigated and demonstrated on the 185 m observation platform with-in the water-level-fluctuating zone of the upstream Three Gorge Reservoir. This study addressed the current adverse situation： the side slopes between the two critical elevations(145-152 m,170-177 m) has experi-enced destructive surge erosion. The cause of surges and their erosion mechanism were analyzed. It was found that surges were the main force causing soil erosion. Traditional slope reinforcement measures and eco-logical techniques like riparian zone construction should be combined organically. Several feasible ecological restoration measures were proposed in respect to slopes of various gradients. In addition, an ecological resto-ration modes for the slopes between the two important elevations in the fluctuating zone was developed pre-liminarily.

Abstract:Based on 1985 and 2001 remotely sensed land use data of Xixi watershed, Jinjiang basin, fractal di-mension and stability index of each major land use type were acquired and the change of the land use spatial pattern were investigated. The results show that the fractal dimension value of the study area decreased from 1. 255 in 1985 to 1. 169 in 2001, and the whole land use spatial structure was simplified. The fractal dimen-sion values of forest land and water land increased, while the values of the other land types decreased. The spatial structure stability index of land use in the study area increased from 0. 245 in 1985 to 0. 331 in 2001. The whole spatial structure stability of land use of the watershed tended to increase. The most stable land use types of Xixi watershed were forest land in 1985 and grass land in 2001, and the most unstable land use type was all farm land in both 1985 and 2001. From 1985 to 2001, the use of the forest land, which covers 50 percent of the total area of Xixi watershed, was out of order with an increasingly unstable spatial structure. The forest land should he planned and managed more properly from now on.

Abstract:Chosen Hekouzhen Longmen region as research area, the study focused on the calculation of re-gional sediment reduction by engineering control and tillage measures(E, T). Approximately 1% of the total area was surveyed in grids to obtain detailed information regarding engineering controls and tillage. Com-bined with existing research findings, the potential and actual amount of soil erosion modulus(Arand A, re-spectively) were calculated for the surveyed blocks of land. Using A/A' as the value of grid where field sur-vey was conducted, regional factors E and T were then obtained as the basis to estimate sediment yield and reduction in sediment yield by engineering projects and tillage practices. The results show that the total area of the eroded land and the spatial distribution of the soil erosion intensity were consistent with the existing research results. The regional soil erosion modulus was estimated as high as 4 004 t/km²·a) and total sedi-ment yield of the study area reached 4.54×108 t/a. Engineering projects and tillage practices possibly con-tributed reduction of 8.00×107 t/a to the total sediment yield. The eroded land concentrated in the middle area of the loess hilly and gully region, including counties of Jiaxian, Linxian, and Shenmu, etc.

Abstract:Urban change detection is an important field of remote sensing applications. This study presents a method for detecting urban change from remotely sensed data. We proposed the differential image anomaly detection method to improve the moving window method using the Landsat TM data. Changsha urban area was chosen as an example to illustrate the method. The results show that the differential image anomaly de-tection method has higher detection accuracy~ 157 out of 178(88.2%) randomly selected pixels were correct-ly detected. In Changsha urban area, 116 101(5.41%) pixels which was natural landscape turned into urban landscape during 2004-2009. Economic development of industrial areas became the main driving force of the urban change in the study area.

Abstract:The objective of this study was to estimate each component of water resources based on water budget formula for a small basin in Northern Shaanxi Province. Liudaogou basin, which is located at wind-water erosion crisscross region in the Northern Loess Plateau, was chosen as the study area. Each component of the annual water budget was estimated through analysis of observed hydrological data and numerical result of surface runoff. Daily water consumption and irrigation water were added into the water budget in order to consider the contribution of human activity. The results indicate that evapotranspiration, runoff, change of water storage accounted for 74.5%, 21.5%, and 0% of the total water budget, respectively, and daily water consumption and irrigation water accounted for 2. 8% and 1. 2%, respectively. The results of this study could provide a basis for sustainable water development and utilization in Northern Loess Plateau, where water resources are extremely limited.

Abstract:Take soil organic matter(SOM) as an example, this study discussed the spatial variability and rea-sonable sampling number for soil organic matter. Sampling schemes with different sample intensities were simulated by extracting data from a soil nutrient database of intensive samples. The results showed that sam-piing density had no significant influence on spatial correlation and model fitting of soil nutrient on a certain scale. It is possible to reduce the number of sample points to satisfy the need of the research regarding spatial variability of soil nutrients. Taking spatial prediction accuracy into consideration, more than 400 samples should be the suitable number to evaluate the spatial variability of SOM on county scale.

Abstract:In order to solve the problem of absent rationality and system in leveled ditch design for runoff har-vesting, the objectives, cross-section parameters, and havesting potential were studied for leveled ditch de-sign in both theory and experiments. The results show that in the growing seasons (March to September) of the 6 years from 2002 to 2008, water stored in the soil on the slope with leveled ditches was significantly higher than that on the natural slope, in the test rainfall intensity and rainfall, the intercepted runoff were 4.41, 64.23, and 104.13 mm on a 25°slope with leveled ditches, and were 5.25, 72.39 mm on a 35°slope with leveled ditches, respectively. The intercepting capacity per unit time increased with the increase of rain-fall intensity, reflecting the importance of high-intensity rainfall to surface runoff harvesting after slope transformation with leveled ditches.

Abstract:The watershed management of Miyun County has made significant achievements under the guiding ideology of water resource protection. However, there has still a problem in evaluating the effectiveness of watershed management quantitatively. Based on 1 700 measurements from 41 watersheds, this study estab-lished a quantitative method for evaluating the effectiveness of watershed management through comprehen-sive statistical analysis. The results show that the effectiveness score of watershed management can be calcu-lated by different engineering measures. No obvious difference was found between the actual values and the predicted results, suggesting that the effectiveness of watershed management can be estimated roughly through the engineering measures. The theory of eco-clean watershed meets the needs of watershed manage-ment of Beijing area, and the realization of the theory will bring more water and soil conservation benefits.

Abstract:A number of test areas were selected in Jiuyuangou small valley. Based on different resolution remote sens-ing images, features of soil and water conservation measures were extracted using GIS technology. The results show that in the first subzone of hill-gully zone of Loess Plateau, the image resolution must be higher than 2.5 m to ap-propriately extract the features of terraces, platforms, sparse forests, and undeveloped planting forests; the resolution level should be higher than 2.5 m for accurate extraction of slope farmland, dammed valley, and grassland converted from farmland; the image resolution level can be higher than or equal to 2.5 m for natu-ral grassland. The resolution level should be higher than 10 m for forest-grass vegetation.

Abstract:Using approaches of literature review, empirical analysis and comparison analysis, the opportunity cost of the upper reaches of Qiupuhe River in 2009 was estimated as of 6.02 X 108 yuan with the opportunity cost method, and the maximum willingness to pay(WTP) was 5.62 X 107 yuan with the contingent vale meth-od(CVM). According to the calculations, the advantages and disadvantages of the two methods were ana-lyzed in details. Based on the semi-efficient market theory and the ecological concept of time-space, the whole compensation process could be divided into two stages, initial compensation and final compensation. The difference between direct economic benefit and ecological preservation cost was set as the initial compensa-tion, which was estimated as of 2.35 X 108 yuan for the study area. The final compensation is total value of the opportunity cost.

Abstract:Canopy rainfall interception is an important hydrological water cycle process in the forest. Canopy interception of planted pine and oriental arborvitae forests was studied in Taihang Mountain region under nat-ural rainfall conditions using a rainfall and stem flow automated acquisition system. The results show that the canopy interception and stem flow of the two forests were positively correlated with total rainfall. Canopy rainfall intercepting capacity of pine was substantially greater than that of oriental arborvitae, but the volume of flowing into the trunk from the interception precipitation is smaller than oriental arborvitae. Specifically, the canopy of pine intercepted 18.90% of the rainfall by average, of which about 3.5% turned into stem flow, and approximately 81.7% of the precipitation reached the ground. The canopy of oriental arborvitae intercep-ted about 13.30% of the rainfall, of which 8.9% conversed into stem flow, and about 88.9% of the precipita-tion fell onto the ground. With consideration of canopy interception features, oriental arborvitae is suitable for planting on gentle slopes, while pine is suitable for planting on steep slopes.

Abstract:50 000 DEM of Chaohu Basin was selected as base data for this study. The extracting accuracy of hydrologic characteristics was evaluated individually for five DEM generalization methods(nearest neigh bor, bilinear interpolation, cubic convolution, structured generalization, quadric surface fitting) based on three parameters including matching error of river networks, matching error of sub-watershed and gully den-sity. The results show that the extracting accuracy of hydrological structure information based on the low resolution DEM followed a descending order of the five terrain generalization methods as： quadric surface fit-ting＞structured generalization＞cubic convolution＞bilinearinterpolation＞nearest neighbor, with very subtle accuracy difference.

Abstract:Based on the daily average water levels of the five gauges around the Taihu Lake observed from 1956 to 2006, the annual characteristic water levels(average, highest and lowest) were obtained. Time series analysis method was adopted, and the decomposition model of trend, period and random components was applied to simulate and fore-cast the annual characteristic water levels of Taihu Lake. The annual characteristic water levels were forecasted for the next 15 years and the future flood scenarios of Taihu Lake basin were also addressed. The results in-dicate that the highest water level of Taihu Lake may reach 4.05 m in 2021, which is significantly higher than the warning water level of Taihu Lake and thus worthy of attention for relevant department.

Abstract:Caragana microphylla is one of the key species for vegetation restoration in Horqin sandy land. Using field investigation and indoor and outdoor experiments, the regeneration of C. microphylla with dif-ferent ages were studied. The results show that there were obvious differences in seed yield and lO0-seed weight among C. microphylla with different ages. Seed density in soil decreased quickly with time. Seed-lings could hardly survive under natural conditions, although sand burial increased the seed germination rate. The branches grew well after stumping treatment. C. microphylla could regenerate through sprouting after a few years. In summary, it is difficult to implement seed regeneration for C. rnicrophylla under natural con-ditions, and sprouting and artificial stumping are the effective regeneration patterns for C. microphylla in the study area.

Abstract:With Fengqiu County of He＇nan Province as the study area, we use ArcGIS 9.2 statistical analysis module(geostatistical analysis) to investigate the spatial variability of soil nutrients. The results show that each of the nutrients in 0-20 cm soil showed a normal distribution and moderate-intensity variation. Specif-ically, soil organic matter had the highest coefficient of variation of 0.665 6, ammonium nitrogen had 0. 411 6, and potassium(K) had 0. 321 3, respectively. Space structural analysis showed that the exponential model fitted best for the distribution of ammonium nitrogen, and the spherical model for K, and the Gaussian model for organic matter. Using ordinary Kriging interpolation, the spatial distribution of organic matter and am-monium nitrogen exhibited banded patterns, while K showed a patchy pattern. The spatial distribution of or-ganic matter was higher along the middle zone along the direction of northeast-southwest, K had higher val-ues in northern central area and lower values in southeast, and ammonium nitrogen was higher in northwest and lower in southeast.

Abstract:The soil locally referred to as a purplish clayey soil(PCS), which was sampled in Deqing County, Zhejiang Province. Both laboratory and greenhouse pot experiments were conducted to investigate availability of soil Hg to crop plants in a rice-cabbage-radish rotation system. Four extractants including 0.1 M hy-drochloric acid(HC1), 1 M ammonium acetate(NH₄OAc, pH=7.0), 0. 005 M Diethylenetriaminepentaacetic acid(DTPA), and 0.1 M calcium chloride(CaC1₂, pH=5.0) were compared for their adequacy in estimating mercury(Hg) availability to crop plants. The results show that the amounts of Hg extracted by each of the four procedures increased with extraction time. The optimal time required for extraction of soil Hg was ap-proximately 30 min the time, however, varied slightly among the four extractants. The amounts of extrac-ted Hg increased with decreasing soil/solution ratio, and a soil/solution ratio of 1~5 appeared to be adequate for soil Hg availability tests. The amounts of extracted Hg decreased in the order of used extraetants as CaC1₂＞HCl＞NH₄OAc＞DTPA. Extractable soil Hg determined using the four extractants were correlated with each other positively significantly, especially between CaC1₂ and NH₄OAc. Significant correlations were also found between extractable Hg in the soil and total Hg concentrations in edible tissues of rice and radish, except for cabbage. Overall, the 0.1 M CaC1₂ extraction provided the best estimation of available Hg in the soil and could be used to estimate phytoavailability of Hg in the rice-cabbage-radish rotation system.

Abstract:Based on the theory for water movement in non-saturated soil, a mathematical model of point source infiltration under adequate water supply was established and solved by using SWMS-3D software. The point source infiltration characteristics were simulated with several typical soils under adequate water supply. According to the simulation results, the infiltration characteristics and related affecting factors was analyzed. It was shown that the cumulative infiltration curve can be well described using Philip model. With same soil texture and bulk density, the sorptivity(A) increased with film hole diameters. The steady infiltration rate (S) increased with film hole diameter and slightly increased with irrigation depth. Furthermore, the simpli-fied infiltration model was proposed for point source infiltration under adequate water supply, including film hole diameter and irrigation depth as parameters. The simplified model was then tested by infiltration experi-ments using typical soils from Loess Plateau and experimental data reported in the studies of the other re-searchers. It was concluded that the simplified infiltration model accurately reflects the point source infiltra-tion characteristics under adequate water supply and can therefore be applied readily to determine the sorptiv-ity and steady infiltration rate.

Abstract:On the basis of established the generalized model, in accordance with the observed data from the reservoirs and silt dams, the sediment volume of small reservoirs and silt dams in Haoshui watershed was estimated using the small reservoir characteristic curve of silt accumulation. The method of generalized deposition was ap-plied to verify the estimated results and to further calculate regional erosion modulus. This approach was simple and the results were proven reliable. This proposed simple sediment estimation algorithm could pro-vide theoretical basis for further research regarding water and sediment in South Ningxia mountainous area.

Abstract:Collapsibility is one of the important properties of loess. When collapses of loess occurred, soil pressure and water content changed correspondingly in sequences. In this study, water immersion tests were conducted with the collapsible loess in a field trial pit. With deployment of the sensors and tension meters in and around the experimental site, a large amount of data was collected regarding the changing patterns and rules of soil pressure and water content. The results show that the soil pressure and matric suction in the lo-ess layers decreased during the experiment. During the deformation, abrupt subsidence of loess often oc-curred when the soil pressure was reaching its minimum and the water content was close to saturation.

Abstract:The contents and speciation of heavy metals in sewage sludge from 10 wastewater treatment plants in the cities of Changsha, Zhuzhou and Changde of Hu＇nan Province were addressed. The potential ecological risk index(IR) was used to evaluate the ecological risk of heavy metals in the sludge intended for agriculture. The results showed that the sewage sludge was rich in organic matter, nitrogen, phosphorous, and potassi-um. As sewage sludge could potentially cause multi-metal contamination, especially Cd, sewage sludge should not be directly used for agriculture. The total content of Cd in sewage sludge ranged from 1.43 to 260 mg/kg and the major speciation of Cd was in reducible form with percentage as high as 28.9%. The major speciations of As and Pb in sludge were also in reducible form, those of Ni and Zn were in acid soluble and re-ducible forms, while those of Cu were in reducible and oxidizable forms, respectively. The results demon-strated that the environmental availability of heavy metals in sewage sludge was high. Based on the results of IR, Cd and As in the sewage sludge imposed a potentially severe risk. Both the single and comprehensive po-tential ecological risks of the heavy metals in the sewage sludge from the industrial areas were extremely seri-ous.

Abstract:This study aims to develop an effective strategy of sustainable development in order to assure the harmonious development regarding water sources among the ecology, economy and society. Using the SWOT analysis method and the sustainable development theory, the SWOT matrix model was established and the sustainable development strategies were proposed for water sources areas in Shangluo City, Shannxi Prov-ince. Considering the specific reality of water sources, four types of strategies including SO (strength-opportunity), WO (weakness-opportunity), ST (strengh-threat) and WT (weakness-threat) strategy were developed and compared. Furthermore, a series of alternative strategies was developed in response to different actual situations by analyzing the internal and external environments and the SWOT factors in the City. The findings of this study could provide certain references to strategy researches on the sustainable de-velopment of similar water source areas.

Abstract:Security of cultivated land resources is the basis for cultivated land protection and national food se-curity. Bayan County as an important base for marketable grain production in the black soil zone of Songnen High Plains was selected as research region. Natural, economic, social and ecological indices were incorpo-rated to establish an evaluation index system in this study. The method of optimal combination was applied to establish index weights, and the method of synthetic index was used to quantitatively evaluate the opera-tion status of the security of cultivated land rescaurces in Bayan County from 2000 to 2009. In addition, prin-cipal component analysis was conducted tq analyze the driving forces. Introducing Cubic curve, the model of security changes of cultivated land resom,was was estabished with nonlinear regression analysis to validate the secure values of cultivated land resources and the eontrlbution of driving forces. The results show that the cultivated land security status of the study area differed over time it is less secure in 2000, extremely unse-cure from 2001 to 9,003, less secure from 2004 to 2005, intermediately secure in 2006, and relatively secure from 2007 to 2009. According to the anialysis, the development of technology, economy, and society, the natural disturbance forces, and the ecologicat influence were the main driving forces for the security changes. A significant cubic curve relation ship was found hetweea the cultivated land resource security and these three kinds of driving forces, reflecting high reasonability arid applicability of the model established in this study.

Abstract:Soil seed banks are of great importance for wetland vegetation restoration. The community succes-sions of the vegetation restored from soil seed banks in a confined space were observed and recorded during the field experiments. Sorensen similarity coefficient(SSC), species composition and corresponding diversity indices(including Shannon-Wiener index, Simpson index, Pielou index and Margalef index) and vegetation coverage indices were calculated and compared at each stage of the vegetation succession to access the status of re-vegetation. According to the measured data, it was found that the SSCs of the original aboveground vegetation and the restored vegetation in 2008, 2009 and 2010 were relatively low, with the lowest SSC of 0.25. The diversity indices showed a trend of decreasing at the beginning and then increased, and finally reached a state similar to that of the original aboveground vegetation. In addition, the vegetation coverage in-dices were higher than 90 %, which satisfy the common requirements of wetland vegetation restoration.

Abstract:The loess hill and gully region of Ordos Plateau was selected as the study area. Seed germinations of Arternisia giraldii, Arternisia sacrorurn and Artemisia ordosica were characterized comprehensively and analyzed systematically. The results indicate that the seeds of Arternisia giraldii have extremely light weight, as low as (0. 090 1±0. 005 1) g per 1 000 seeds. This trait allows the species to achieve higher dis-persal rate than the others. Furthermore, seed germination rate of Arternisia giraldii remained almost same as the other species with similar traits. This suggests that the light seed weight of Arternlsia giraldii was clearly not a disadvantage for the success of seed germination. Instead, it enhances the effective adaptability of Arternisia giraldii to the gully habitat.

Abstract:Urban landform is one of the basic geographic elements, which determine the formation of the city and the layout direction of development. In this study,Xianyang City was chosen as the study site. DEM data was analyzed and landform maps of elevation, slope and aspect were generated using ArcGIS software. The results indicate that the landform of the city was consisted of river floodplains, T1 terrace, T2 terrace, T3 ter-race and Loess Plateau, elevated from Weihe River. The terrain was dominantly flat (0~~5~) , accounting for 83.6% of the total area, with lands of gentle slope (5-15) accounting for 11.8, and a small portion land with steeper slopes. Approximately 61% of the total area faces southwest, south and southeast, and the southeast faced land accounted for 34.6%. The land facing northwest, north and northeast occupied approxi-mately 18.9% of the total area. The development of urban construction mainly occurred along the Weihe River and the transportation and drainage systems were influenced by the terrace landform.

Abstract:The influences of Xiaolangdi reservoir on the replenishment of the Yellow River estuary wetland were analyzed, and the changes before and after the operation of the reservoir on the landscape pattern of Yellow River Delta wetlands were detected using remote sensing. The results show that rainfall was an im-portant source for the wetland replenishment. As the rainfall was unevenly distributed each year in the study area, periods ecologically short of water often occurred. From May to July each year, lateral seepage from the Yellow River and rainfall infiltrations were overlapped, providing large amount of water supply to re-charge the wetlands. The water supply of lateral seepage showed great influences in about 2.5 km of the ri-parian buffer, but no obvious effect on the entire wetland. After the operation of the reservoir, the total area of the wetland increased slightly, specifically with areal reduction of 90.29 km² in natural wetland and areal increase of 150.11 km² in artificial wetlands. The coastal wetlands have experienced sea erosion generally. Overall, the area of the wetlands in the study area increased substantially and the salinization process has been restrained after the operation of the reservoir.

Abstract:The carrying capacity of the environment and resources is one of the important indices for dividing main functional regions. Considering the connotation of the relative carrying capacity of resources as well as the population and economic factors, a standard for dividing main functional regions was constructed using arithmetic average model. Shandong Province was chosen as the study area and its 17 cities as the basic eval-uation units. Three main functional areas including optimal development area, key development area and de-velopment prohibited area were divided by taking the whole country and the whole Shangdong Province as reference regions. Recommendations were also proposed specifically for the three main functional regions. The results show that the relative carrying capacity model can be applied well in major function oriented zon-ing, which can contribute to promoting regional sustainable development.

Abstract:With Andamu River of suburban Beijing City as the research object, representative indices inclu-ding river ecological features, hydrological characteristics, morphological features and landscape entertain-ment functions were selected in this study. Based on the comprehensive index analysis method with incorpo-ration of certainty and uncertainty of pair analysis, the ecological environment of the river was evaluated and classified into four categories： same, partially different, largely different and totally different. At the same time, the evaluation results were analyzed by adopting spatiotemporal analysis. The results show that the lo-cal ecological environment of the Andamu River was almost completely destructed in recent years. Urgent measures such as strengthening river management, treating rural wastes reasonably and effectively, reducing unnecessary human activities and balancing tourism development and ecological management should be em-ployed the key contents of river ecological regulation in the next step.

Abstract:Standing dead trees(SDT) are widespread in forest ecosystems and have a particular important in-fluence on forest development and succession. Based on vegetation community survey in plots of 4 hm² in Mulan-Weichang forest farm of Hebei Province, this study analyzed the species, diameter structure, bio-mass and distribution pattern of SDT in the rocky mountain area of Northern China. The results indicate that the SDT involved eight species. The density of the SDT was 79.25 stems/hm² , accounting for 10.13% of to-tal tree numbers in the plots. The biomass of the SDT was 18.46 t/hm² , accounting for 6.88% of the total biomass in the plots. Among them, both the number and the biomass of Populus were the greatest, account-ing for 83.60% and 90.58% of all the SDT, respectively. The diameter at breast height(DBH) of the major-ity of the SDT was smaller than 22 cm. The average uniform angle index of all the SDT of the forest is 0. 543, indicating a random distribution pattern.

Abstract:The enforcement of grain-to-green program converts large areas of farmlands to forests; its effi-ciency in turn affects the evaluation on the impacts of the policy. Farmlands covering a total area of approxi-mately 2.54 × 106 hm² were returned to forests in Qinba mountainous area, accounting for 10% of all the farmland planned to be converted. According to the questionnaires and the interviews carried out on 10 town-ships from 7 counties of the 3 provinces, the ecological benefits of the porgram were becoming explicit while the economic benefits did not match the expectation, which mainly results from the lack of scientific planning and technical instruction. Consequently, the ecological goal of the government has been achieved while the economic goal to substitute long-term income sources of the farmland owner has not been achieved completely (encouraging farmers to work temporally in the cities cannot ensure their income source permanently, espe-cially at their old ages). To achieve both of the ecological and economic goals, instruction and demonstration of feasible technologies and follow-up technical supports are required.

Abstract:Dynamic changes and structural efficiency of land use can provide reference for decision-making in the structural adjustment of regional land use. Based on detailed landuse survey data collected from 1998 to 2008, the landuse dynamics of Heilongjiang Province in the ten years were analyzed by determination of land-use change extent and dynamic degrees of individual landuse type. The DEA model was applied to analyze the landuse structure efficiency. The results show that the areas of the individual landuse types changed in differ-ent directions and to various degree. Specifically, Harbin and Suihua City experienced the greatest change, owing to the administrative adjustment within Heilongjiang Province. Overall, transportation land decreased faster than the others, and other agricultural land and land for water conservancy facility increased faster. The dynamic degrees differed among the thirteen cities(area) of the study area. According to the DEA mod-el, the cities were divided into efficient and inefficient cities. Larger redundant allowance of some land use type was the main reason that led to the underachievement of the land production in the inefficient cities. In the other hand, the low GDP and undeveloped first, second, and third industries were the main reasons for the low efficiency of land production. Last but not least, landuse structure adjustment was proposed accord-ing to the DEA results.

Abstract:Shangluo City is a typical area of Qinling mountainous region, which is an ecologically sensitive area where ecological protection is of great significance, using ETM＋ images and NDVI of MODIS, the study investigated the different influence of land use degree on vegetation coverage. The influences of human activi-ties on lands were analyzed throughout and locally. Statistical analysis was conducted on the ＂cells＂, which was the towns and districts of the city. The land use degrees were then calculated globally over the whole study area and locally on the cells. After the spatial autocorrelation being computed, the land use degrees were found closely correlated with the cumulative percentages of NDVI. A formula was proposed using both the land use degrees and NDVIs, and was then applied to analyze the impacts of land use change on the envi-ronment during the past 9 years. The results show that in most of the region, the ecological environment was improving faster than or nearly equal to the land use degradation. This is a remarkable achievement made by ecological restoration efforts in study area. The ecological restoring forces were strong in most towns during the 9 years, which means that the related policies were enforced well in both economic development and envi-ronmental protection. However, the land use degrees in some towns still need to be improved, and more at-tention should be paid to the regional ecological environment.

Abstract:Based on field-observed data from Luohui Irrigation District, grey correlation analysis method was applied to analyze the relations between groundwater mineralization, depth and soil salt content. The model of soil water-salt dynamics was then established based on the analysis. The results show that groundwater mineralization was the main factor affecting soil salt contents, and also played an important role in transfer-ring salts. The interaction among various factors formed coupling relationship under the complicated condi-tion. As affected by external factors, it can be preliminarily determined that the soil of the Irrigation District was in desalination condition and in a relative stable state. The variation tendency of soil salt content differed from those of groundwater mineralization and groundwater depth. The quantitative model established in this study described well the response of groundwater dynamic to various factors with sufficient high accuracy. The combination provides a feasible method for analyzing the mechanism of soil water-salt dynamics under the condition of shallow groundwater during the crop growing season.

Abstract:Aiming at ecological zone construction, Muping district of Yantai City was selected as the study site. An index system for regional ecological carrying capacity(ECC) evaluation was estabhshed, including factors such as resource carrying capacity, environmental carrying capacity and social supporting ability. Using principal components analysis (PCA) and fuzzy synthetic evaluation model(FSEM) with SPSS and Matlab, the changes of ECC in Muping district from 2006 to 2010 were evaluated quantitatively. Further-more, the main factors which caused the changes of the ECC were discussed. The ECC declined continuously from 2006 to 2010, downgraded from good level to incapable level, especially resources carrying capacity. The analysis results of this study reflected well the actual situation of Muping District, indicating the estab-lished evaluation index system is sensitive to regional ecological environment and has acceptable efficiency and applicability to evaluate ECC in the areas with rapid economic development. It was also confirmed that PCA and FSEM can be applied to evaluate the ECC adequately and operationally.

Abstract:Ecological footprint(EF) is one of the most important methods to evaluate the sustainability of re-gion development. The ecological footprints and ecological capacity(EC) were calculated based on the ecolog-ical footprint theory and model for Mianyang City during 2000 to 2009. The results show that within the study period, the ecological footprint per capita increased, with apparent fluctuations, from 1. 377 2 hm2 to 2. 408 7 hm² , the ecological deficit per capita increased sharply from 0. 954 4 hm2 to 1. 922 0 hm² , and the ec-ological capacity per capita increased only slightly. In contrast, the ecological tension index arose from 3. 257 6 to 4. 949 3, and the ecological footprint of ten thousand Yuan GDP decreased from 2. 252 1 hm² to 1. 599 6 hm². Especially, the ecological footprints and ecological deficits showed sharp growth since the reconstruc-tion after the 5 -12 Wenchuan earthquake in 2008. With increasing consumptions of natural resources in Mianyang City, the conflicts between ecological footprint and ecological capacity were amplified suggesting an unsustainable state of the present developing model and poor harmony between socioeconomic development and ecological environment. In order to achieve the goals of eco-city construction plan and sustainable devel-opment strategy in Mianyang City, recommendations were made based on the analysis of this study, inclu-ding controlling the size of population, adjusting the structure of agricultural industry, protecting the re-sources of cultivated land, and optimizing life style and production mode of the people.

Abstract:With the use of geographic concentration index, imbalance index and other statistical index, and the help of software ArcGIS 9.0, this paper explored spatial distributions of county territory cultivated land scale and cultivated land per capita of Hernan province in 1994, 1999 and 2004. The paper also explored the change quantity and change speed and spatial variation characteristics of county territory cultivated land scale and cultivated land scale per capita. The main conclusions are as follows. Firstly, the spatial distributions are that the cultivated land scale of southeast part is bigger than that of northwest part in Hetnan Province. Sec-ondly, in the former research period(from 1994 to 1999), the county-level regions where the cultivated land scales were increased are centralized in the space and quantity~ those where the cultivated land scales were re-duced are scattered in the space and quantity. But in the latter research period(from 1999 to 2004), Hetnan Province had the opposite development momentum. Thirdly, the cultivated land scale changes by county ter-ritory are related to those of the terrain and landform. Fourthly, the regions where cultivated land scale per capita is relatively more mainly concentrated in regions along the Beijing-Guangzhou railway, the part re-gions of Sanmenxia City and Nanyang City. Fifthly, change quantities of cultivated land scale show the spa-tial distrihution of "more in the south。fewer in the north" in He'nan Province. Finally, higher change rate of cultivated land scale per capita mainly distributed in the southwest He'nan Province and those of the part regions of Sanmenxia City and North He'nan Province are relatively low.

Abstract:Based on global and local spatial autocorrelation analyses of exploratory spatial data, this study an-alyzed regional pattern and driving forces of cultivated land use change in Jiangxi Province from 1980 to 2007 by adopting GIS technology and Geoda software. The results indicate that during 1980-2007, the global spatial autocorrelation of cultivated land change in the study area was significant, as shown by the value of Global Moranrs I. The changes of cultivated land in Jiangxi Province displayed a clear spatial clustering effect along with a spatial homogeneity within individual zones such as northern plain, surrounding mountains, and inner hills. The majority of the counties had a positive spatial correlation in land use change. Specifically, ＂high-high＂ correlations were mainly found in the northern plain and surrounding mountains of the province, while ＂low-low＂ correlations were found in the hilly areas. The main driving forces influencing cultivated land change varied in different regions.

Abstract:The ten districts of Shaanxi Province was selected as the study area. The coupling relationship be tween economic development and ecological environment was analyzed using entropy method, coupling degree model and GIS technology. According to the cluster analysis, the coupling relationship could be divided into five types. The spatial characteristics and internal differences of coupling levels were discussed. Overall, the coupling relationship between economic development and ecological environment in the province was low and needs to be improved. Each level of coupling relationship showed obvious local convergence, and the coupling levels next to each other displayed strong geographic proximity.

Abstract:Studies regarding urban ecological land can provide scientific methods and information for decision-making in land resource use and planning. Urbanization level of Lanzhou City during 1999-2008 is evaluated using entropy method along with integrated urbanization index system. Furthermore, the supply and demand of urban ecological land was estimated based carbon-oxygen equilibrium theory. The coupling relationship be-tween urbanization level and ecological land supply and demand was investigated by applying grey correlation analysis. The results show that the grey correlation degree between economic-urbanization and ecological land supply and demand was the biggest, followed by population-urbanization. The changing trend of eco-nomic-population-urbanization was highly consistent to that of ecological land supply-demand.

Abstract:The eigenvalues of particle size distribution were analyzed for the sediment of Yellow River from 1950 to 2005 and the formula addressing mean annual sediment input in any reach of the Yellow River were developed to account the sediment sources inputting into the Ningxia-Inner Mongolia reach of the Yellow River. The results show that a huge amount of sediment was delivered into the Ningxia-Inner Mongolia reach annually from 1950 to 2005, and the mean annual sediment input amount varied with time. With data mining and field investigation, we found that the variations were results from the interaction between desert and river as Yellow River flows through the deserts such as Tengger Desert, Hedong sandyland, Ulan Buh Desert and Kubuqi Desert in Ningxia and Inner Mongolia Autonomous Region, where aeolian sediment trans-portation was a major input source into the river. Furthermore, in the upper reach of ＂Ten Great Gullies＂ with great bed gradients, the aeolian sediment covering river banks can be eroded easily by both wind and water and carried into Yellow River by floods. In summary, we think that the key to control channel aggra-dation of Yellow River is reducing the amount sediment input into the Ningxia-Inner Mongolia reach, which in turn can be achieved through comprehensive prevention measures such as soil and water conservation, eco-system restoration and engineering measures, which especially should be strengthened in the ＂Ten Great Gullies＂ region.

Abstract:Using questionnaires, this study analyzed the farmers＇ attitudes and responses towards the range-land enclosure policy(REP). The results show that 92. 4% of the interviewees believed that a significant achievement has been made ever since the new policy went into effect. Meanwhile about 78.0~//0 of the inter-viewees supported the policy. However, a large proportion(42.60//oo) of the interviewees felt that their liveli-hoods had been adversely affected by the REP. Furthermore, 81.8~ of the interviewees admitted that the illegal activities like grazing at night still exist. The study found that the immediate interests of vulnerable groups(low lever education, low lever income, harsh living condition, elders and women, etc.) were largely ignored, which turned out as the main problem of the deployment of REP. Consequently, we proposed that full attention should be paid to the residents＇ basic living and developing rights. At the same time, for the sake of the comprehensive development of the ecology, economy and society, the local government must develop industries with local advantages.

Abstract:Using questionnaires, this study analyzed the farmers＇ attitudes and responses towards the range-land enclosure policy(REP). The results show that 92. 4% of the interviewees believed that a significant achievement has been made ever since the new policy went into effect. Meanwhile about 78.0~//0 of the inter-viewees supported the policy. However, a large proportion(42.60//oo) of the interviewees felt that their liveli-hoods had been adversely affected by the REP. Furthermore, 81.8~ of the interviewees admitted that the illegal activities like grazing at night still exist. The study found that the immediate interests of vulnerable groups(low lever education, low lever income, harsh living condition, elders and women, etc. ) were largely ignored, which turned out as the main problem of the deployment of REP. Consequently, we proposed that full attention should be paid to the residents＇ basic living and developing rights. At the same time, for the sake of the comprehensive development of the ecology, economy and society, the local government must develop industries with local advantages.