Abstract:To investigate the effects of fertilizing and tillage on characteristics of runoff yielding, the plantation mode "winter wheat-summer maize" was taken as the research object. Five treatments were set up, which were CK(T₀), combined application of manure and fertilizer(T₁), chemical fertilizer(T₂), chemical fertilizer with increasing fertilization(T₃) and contour tillage with chemical fertilizer(T₄). The characteristics of runoff yielding were studied in runoff plots from 2008 to 2012. Results are as follows: Runoff induced rainfall occurred from May to September in the purple soil area, with the maximum runoff observed in June. Runoff was relatively consistent with rainfall. Runoff depths ranged from 9.57 to 100.36 mm and runoff coefficients, from 0.05 to 0.19. Both average annual runoff depths and average annual runoff coefficients were presented in the order of T₀ > T₃ > T₂ > T₁ > T₄. The fertilization treatments reduced runoff by 25.90% to 47.50% as compared with the CK and T₄, by 25.46% as compared with T₂. Annual rainfall in relation to annual runoff can be expressed by a power function. Differences in annual runoff and runoff coefficient between the treatments are significant according to variance analysis. Fertilization, tillage and rainfall are the main factors influencing runoff.

Abstract:Impacts of cement content on soil biological activities in vegetation-concrete substrate are discussed. By taking vegetation-concrete substrate covered by common revetment herb as the study object, the soil biological activity index(SBAI) is calculated based on experimental data of urease, invertase, alkaline phosphatase, microbial biomass carbon and microbial biomass nitrogen. Results indicate that adding cement can reduce soil biological activities and the SBAI was at a higher level with low cement content. Under the same gradient of cement content, the SBAI of unmanaged samples is obviously lower than managed samples covered by Cynodon dactylon and Medicago sativa L., which shows that plants can improve the level of soil biological activities to a certain extent.

Abstract:The daily sap flow velocity of wheat was measured using Dynamax Flow 32 and the environmental factors were monitored using Automatic Weather Station System at the jointing and flowering stages. The relationships between sap flow velocity and environmental factors were also analyzed. Results showed that (1) the curve for diurnal variation of sap flow had a peak. The trend was the same at jointing and flowering stages. Sap flows at the two stages started at 7:00-8:00 and 6:00-7:00, respectively. The maximum sap flow velocity was observed at 12:00-14:00, and the values were 1.90 and 2.66 g/h (24th and 25th, April, sunny day, jointing stage) and 3.39 and 2.96 g/h (0518 and 0519, sunny day, flowering stage), respectively. Then the sap flow velocity dropped down to the lowest at 21:00 and no sap flow was observed at night. The value of sap flow on sunny day was higher than that on cloudy day. (2) There was a similar trend between sap flow velocity and environmental factors. The relationships among them were significant. There was a negative significant correlation between sap flow velocity and humidity, while it showed positive correlations with other environmental factors. From correlation analysis, their coefficients were in the order of photosynthetically active radiation > air temperature > humidity > wind speed.

Abstract:This study was conducted in an old plastic film mulching field to promote the reusing techniques of plastic film mulch in the Hetao Irrigation District, with oil sunflower cultivation in open field as the control. In soil ice crust and soil moisture recovering periods and before oil sunflower sowing and seedling periods, soil moisture and soil salt in 0-100 cm soil layer were measured within old plastic film belts, near old plastic films and between old plastic films, respectively. Moreover, emergence and seedling growth of oil sunflower were measured within old plastic film belts and between old plastic films, respectively. Results showed that reuse of the plastic film mulch increased topsoil moisture in old plastic film mulching field, decreased topsoil salt within old plastic film belts, but increased topsoil salt near and between old plastic films. Reuse of the plastic film mulch had no significant effect on deep soil moisture and soil salt. Reuse of the plastic film mulch shortened oil sunflower emergence time, increased oil sunflower emergence rate and survival rate, promoted oil sunflower seedling growth within old plastic film belts, but extended oil sunflower emergence time, decreased oil sunflower emergence rate and survival rate, inhibited oil sunflower seedling growth between old plastic films. In cultivation of oil sunflower with the reusing technique of plastic film mulch, oil sunflower should be sowed in the soil within old plastic film belts, but should not be sowed in the soil between old plastic films.

Abstract:The biggest sea buckthorn(Hippophae rhamnoides) artificial forest in the Asian is located in Jianping County, Liaoning Province, China, which has an important role in controlling soil and water loss. A large area of sea buckthorn in this district died for various reasons in recent years. In order to study the effects of sea buckthorn degradation on soil properties and soil and water loss, the forest's death rate was surveyed by sample plot, and soil physiochemical properties and soil and water loss were measured for different death rates. As the number of sea buckthorn living trees decreased, soil bulk density increased by 1.4%~7.31% and soil porosity and organic matter decreased by 7.81%~21.89% and 9.33%~27.65%, respectively, which shows that sea buckthorn degradation could destroy soil texture and nutrient significantly. The artificial rainfall simulation showed that soil erosion modulus of 539 t/(a·km²) was measured in well grew sea buckthorn forest and it increased with the increase in sea buckthorn death number. Soil erosion modulus reached 1 526 t/(a·km²) when sea buckthorn was almost replaced by elm(Ulmus pumila L.) because of removal of died sea buckthorn. The aggravation of soil and water loss and the deterioration of soil properties damaged soil organic matter and texture, then the death rate of sea buckthorn accelerated, and thus vicious cycle formatted.

Abstract:Rainfall characteristics and their effects on loess slope erosion in the loess hilly region of the western Loess Plateau were studied using the runoff plots located in the Anjiagou watershed, Dingxi City, Gansu Province and the data observed from 2009 to 2011. Results showed that in the condition of natural rainfall, runoff process under different treatments could be divided into runoff producing, maximum runoff, stability of runoff and disappearance of runoff and soil erosion, into erosion producing, maximum erosion amount and curtailment erosion. The eight treatments, in order of the decreasing total amounts of runoff and soil loss, were 15° spring wheat, 10° spring wheat, 10° Pinus tabulaeformis arboreal forest, 15° waste land, 15° Hippophae rhamnoides shrub forest, 10° waste land, 15° Pinus tabulaeformis arboreal forest and 10° Hippophae rhamnoides shrub forest. From the hierarchical clustering, on the 10° slope, Hippophae rhamnoides shrub forest had an obvious effect of soil and water conservation, while on the 15° slope, Pinus tabulaeformis arboreal forest had an obvious effect of soil and water conservation. Therefore, combined with the climate and environment of test site, 10° slope is suitable for planting Hippophae rhamnoides and 15° slope, for returning farmland to forest.

Abstract:The flow patterns involved in rill erosion process on loess hillslope are studied by a multi-plot experiments under simulated rainfall with addition of steady in-flow through the tops of the plot. The results showed that: (1) The Reynolds number of rill flow, a judging index of flow pattern, changed under different rainfall intensities and slopes with a overall rise and finally a stabilized trend. A power function equation can be used to describe the two processes. (2) The average Reynolds number of slope rill flow increases with rainfall intensity and slope. Its relation to both rainfall intensity and slope can be described by a logarithmic equation; and to both of the two factors, by a dual power function equation. (3) The rill flow pattern is the laminar flow under different rainfall intensities and slopes. Only under the two of the largest rainfall intensities and slopes, rill flow may be in the transition region. (4) The average Reynolds number, a measure of fluid turbulence, varies between 327 and 457 and remains in the regime of normally considered laminar flow. The change of the Reynolds number, with the amount of the flow, is a significant positive linear correlation.

Abstract:The objective of this study was to investigate the law of runoff and sediment yielding from original and disturbed sites in the Shenfu-Dongsheng coalfield by a simulated rainfall experiment. Results showed that the time for runoff initiation in disturbed sites was 1.8 to 11.7 times that in original sites. However, runoff rate for disturbed sites was 5% to 54.4% less than that for original sites. The initial sediment concentration, average sediment concentration and sediment yield in disturbed sites were 1.1 to 5.8, 1.2 to 6.3, and 2 to 12.7 times of those in original sites, respectively. Runoff and soil erosion in disturbed sites occurred under high intensive rainfall because of lower bulk density, higher porosity and greater infiltration rate as compared with original sites. Once erosion began, disturbed sites were subject to erosion under the same rainfall condition due to smaller critical shear resistance and could result in larger erosion rate. It was found by regression analysis, there existed a linear relationship between sediment yield and flow shear stress.

Abstract:A study with 10 treatments was conducted in the long-term observation station of the South Xiaohegou watershed to investigate the law of soil and water loss under different surface treatments. Results show that soil loss was not consistent with runoff processes, but affected by slope. The soil loss incremental rate generally increased with increasing slope degree. However, when slope increased, slope length for collecting the same amount of water as at the smaller slope increased, which could lead to a reduction in water infiltration into soil, but the total infiltration increased. Therefore, runoff amount did not show a proportional increase with slope increase when slope was greater than 20°which was determined as the threshold. The study also shows that a mixed plantation of Chinese pine tree with sea-buckthorn at a coverage of 65% could significantly reduce soil and water loss, with a sediment concentration of 2.377 kg/m³ which was 57.77% lower than soil loss on the bare land. The averaged runoff of 0.121 m³ under the plantation was 19.74% lower than the bare land. In 2012, soil erosion index for the Yangjiagou watershed where biological control practices for soil and water conservation had been applied was 2 589.95 t/km² lower than the Dongzhuanggou watershed which remained in the natural conditions without any human disturbance.

Abstract:The change of mud drainage and consolidation plays an important role in reasonable arrangement of drainage system in the construction process of hydraulic fill dam. By taking moderate silty loam as the research object, mud was separately packed at three soil-water ratios(1:1, 1.5:1 and 2:1) in four polyethylene corrugated pipes of 50, 100, 150 and 200 cm in height and indexes for quantity of water discharge, up-water separating, penetration and the amount of consolidation-subsidence were measured. Results show that all the indexes increased with increasing mud height at the same soil-water ratio. However, the indexes decreased with increasing soil-water ratio in the same height mud. The amount of discharged water and subsidence were mainly observed in the first 24 h, with the maximum 89.48% and 93.24% in total quantity, respectively. Therefore, in practice, it is necessary to enhance the previous up-water discharge at low soil-water ratio and meanwhile, no arrangement of drainage systems in surface mud is needed except enhancing the drainage measures of penetrating water.

Abstract:The Yaji experimental site of Institute of Karst Geology, Chinese Academy of Geology Science, was selected as the study area to discuss the effects of karst physiognomy on soil microbial abundance and enzyme activity. The gene abundances of amoA, as the index of ammonia-oxidizing bacteria(AOB) communities, were determined by real-time quantitative PCR(qPCR), while microbial community population and soil enzymes were analyzed using dilute plate incubation counting and colorimetric methods, respectively. Results show that the enzyme activities and total microbial numbers of soils in saddle back, piedmont slope and karst depression increased while the soil AOB decreased. Moreover, the abundances of AOB communities had a significantly positive correlation with fungi, while it had a significantly negative correlation with sucrase activity.

Abstract:Due to serious soil salinization, the Yellow River Delta has become one of degraded ecosystems in China. Effects of different plantations, including Robinia pseudoacacia pure forest & mixed forest, on soil chemical properties were studied in order to explore the relationships between plantation modes and soil chemical properties and thus rationally utilize the land resources of large scale saline region. Results showed that creating R. pseudoacacia in coastal saline effectively inhibited soil salinization and degradation, reduced alkalinity, and improved soil fertility. The effect of soil alkali salt dischange of mixed plantation was better than that of pure forest. Soil chemical properties were significantly different under different plantation modes. Soil exchangeable calcium and magnesium did not show phenomenon of accunulation in sruface, but the effective sulfur and phosphorus did not change significantly. Moreover, there was a certain correlation between the chemical indicators. Soil pH value had significantly negative correlations with total nitrogen, exchangeable calcium and exchangeable magnesium and there was a significant negative correlation between soil available sulfur and available phosphorus. The integrated effect on soil properties in mixed plantation was higher than Robinia pseudoacacia pure forest. Moreover, the combined effects on soil fertility in different mixed modes were not the same. The mixed plantation of R. pseudoacacia and Fraxiinus velutina performed the best effects on soil fertility, followed by the modes of R. pseudoacacia×Ulmuspumila ＆R. pseudoacacia×Ailanthus.

Abstract:Pin-plugged method and meteorological observation method were adopted for analyzing wind erosion and wind deposition changes on surfaces of farmlands reclaimed in two years and in one year in Cele County of Xinjiang Wei Autonomous Region. The result indicates that wind deposition occurred in the range of 0-3 H (tree height) before and behind shelter belts along prevailing wind direction, the wind deposition volume upwind shelterbelt was more than that on the surface of downwind shelterbelt obviously, and on the surface of the middle part between two shelter belts it mainly showed wind erosion. Winter wheat planted in front of jujube tree seedlings could resist effectively wind erosion around jujube tree seedlings' roots in certain degree. On the surfaces of three natural underlying surfaces preserved with different vegetation coverage, the higher the vegetation coverage and plant height were, the stronger the resistance and wind deposition ability were. Because it was loose and bare surface without cultivation and there was no vegetation on newly reclaimed land, maximum wind erosion amount occurred in every same phase. Wind erosion and wind deposition changes not only have close relationship with vegetation coverage, shelter belts' structure, wind velocity and wind direction, but also have relationship with surface microtopography.

Abstract:By field investigation in combination of indoor control and leaching, a study was conducted on the accumulation amount, water-holding capacity, water-holding rate and water-absorption rate of the litters under four main forests(evergreen broad-leaved forest, broadleaved deciduous forest, conifer-broadleaf forest and evergreen coniferous forest) in the Longmen Mountains fault zone. The accumulation amount of litters under the forests decreased in the order of evergreen coniferous forest(8.26 t/hm²) > broadleaved deciduous forest(6.80 t/hm²) > conifer-broad leaf forest(5.52 t/hm²) > evergreen broad-leaved forest(4.61 t/hm²), and the storage percentage of semi-decomposed litters was higher than that of un-decomposed litters. The water-holding capacity and water-holding rate of litters at different decomposition degree changed logarithmically, while the water-absorption rate assumed a power function of soaking time. Under the four main forests, the litters in semi-decomposed layer had a stronger water-holding capability than that in decomposed layer, and the water-holding capability of litters under broadleaved deciduous forest and conifer-broadleaf forest was stronger than the others, while the litters of evergreen broad-leaved forest had the lowest water-holding capability. The results indicated that we should fully exert the functions of soil and water conservation of the semi-decomposed litters, and select broadleaved deciduous forest and conifer-broadleaf forest needle modes in recovering and reconstructing forest vegetation.

Abstract:To rationally use native species in the loess hilly-gully region and find appropriate mixture ratio of native species for artificial grassland construction, Bothriochloa ischaemum and Lespedeza davurica were sowed by the seven row ratios of 0:10, 2:8, 4:6, 5:5, 6:4, 8:2 and 10:0 in a terraced field. The seasonal soil moisture characteristics, yearly aboveground biomass and water use efficiency were investigated and compared in two years with different rainfall amounts(663.4 mm in 2011 and 458.2 mm in 2012). Results indicated that soil water consumption and replenishment were closely related with the mixture ratio of the two species in the mixture grassland, mainly affected by yearly rainfall amount and seasonal distribution. In 2011, soil water supplement reached the 20-260 cm soil layer, and the spatial and temporal difference of soil moisture between mixture ratios and soil layers were reduced because of plentiful rainfall in the rainy season. Both in 2011 and 2012, Bothriochloa ischaemum and Lespedeza davurica mixtures at 6:4 and 8:2 ratios had higher aboveground biomass production and water use efficiency.

Abstract:Soil water-stable aggregates are the base of soil fertility. The content of water-stable aggregates was measured under controlled conditions to determine how short-term grazing influences soil aggregate stability and biomass in an alpine meadow on the northeastern edge of the Qinghai-Tibetan Plateau. Results showed that the content of water-stable macro-aggregates increased under moderate grazing. Organic carbon in water-stable aggregates was reduced with increasing soil depth. Compared with the control, organic carbon in > 1 mm water-stable aggregates within 10 cm of soil surface was significantly reduced under moderate grazing, but < 1 mm water-stable aggregates in the 10-20 cm soil layer increased. The biomass was significantly increased within 10 cm of soil surface with the increasing grazing intensity. Rhizosphere soil under moderate grazing had the largest amount of fungi and the number of actinomycetes increased with the increasing grazing intensity.

Abstract:In order to investigate the effect of changes of forest type converted from chinese hickory(Carya cathayensis Sarg.)-evergreen broad-leaved mixed forest to pure C. cathayensis forest on litter and soil hydrological characteristics, we studied the difference of the water conservation abilities between C. cathayensis broad-leaved mixed forest and pure C. cathayensis forest in 0, 5, 10 and 20 a by using comparative sampling adjacent plots method. Results showed that woodland litter water-holding capacity, absorption rate and soaking time relations were in line logarithmic and exponential functions. The 0 a woodland litter accumulation, maximum water-holding capacity and effective interception amount were significantly higher than 5,10, 20 a C. cathayensis woodlands. As the extension of managing time, the woodland litter accumulation, maximum water-holding capacity and effective interception amount showed a downward trend. Compared with 0 a woodland, others decreased by 38.2%~54.6%, 58.1%~69.7% and 21.0%~33.2%. The differences of the soil bulk density, non-capillary porosity, capillary porosity, total capillary porosity and water holding capacity and other indicators in different managing histories of C. cathayensis forest were not significant. Compared with the water-holding capacity (21 450.0 t/hm²) of 0 a woodland soil, through different years of management, the water-holding capacity decreased from 10.6% to 20.4%. All of these indicate that the forest litter and soil hydrological effects were reduced after the C. cathayensis evergreen broad-leaved mixed forest was converted to pure C. cathayensis forest.

Abstract:In order to determine the relationship between influencing factors and canopy interception of Phyllostachy edulis forest, the canopy interception and influencing factors were studied with location fixed observation method from April 2012 to March 2013. Results showed that the throughfall, stemflow and canopy interception accounted for 60.6%, 6.7% and 32.7% of total precipitation during the study period. Canopy storage capacity and stem storage capacity of Phyllostachy edulis forest were 0.82 and 0.1 mm, respectively. Leaf area index(LAI) was introduced as a canopy characteristic and the correlation between LAI and canopy interception was analyzed. Canopy interception of each month increased with the increase in mean monthly LAI to some extent. Mean monthly canopy interception rate decreased with the increase of mean monthly LAI outstandingly. The environmental factors influencing canopy interception were evaluated by gray relational grade which showed an order as: rainfall intensity > precipitation > wind speed > temperature > wind direction > air humidity, while the order of the environmental factors influencing canopy interception rate, as evaluated with the same method, was: temperature > wind direction > precipitation > wind speed > rainfall intensity > air humidity.

Abstract:In order to examine disparity and similarity of landuse types in karst rocky desertification area under different environmental conditions, a quantitative research on basin, mountain and gorge was made with support by 3S technology, using SPOT images(2.5 m resolution) in 2008. Results are as follows: (1) Rocky desertification would occur potentially in dryland, shrubland, sparse woodland, natural grassland, wild grassland and bared rocky area. In detail, shrubland would degrade into the moderate rocky desertification area; sparse woodland, natural grassland and wild grassland would degrade into the serious rocky desertification area or below; inferior ranks to it dryland would potentially degrade into any type of rocky desertification; and 100% bared rocky area would degrade into the serious rocky desertification area or worse. (2) There were different rocky desertification rates and strengths in the same landuse type under different environmental conditions. (3) Generally, the geomorphologic types, in order of decreasing rocky desertification rate, were gorge, basin and mountain. (4) Rocky desertification process in gorge and basin areas showes intensity increase, and the process possibly would also showes phenomenon as enlarge the area and increase intensity of rocky desertification in karst mountainous environment.

Abstract:A study was conducted at different degrees of canopy coverage in Pinus tabulaeformis plantation in the Taiyue Mountains, Shanxi Province, to analyze the hydrological functions of litters and soil layers. The results showed that: (1) The total storage capacity of litter layers was about 7.43~10.86 t/hm², and litters increased with canopy coverage increasing. The maximum water holding rate ranged from 276.54% to 311.33% and the maximum water holding depth, from 8.02 to 14.34 mm, showing an order in canopy coverage of 0.7 > 0.6 > 0.8 > 0.5. The forest with canopy coverage of 0.7 showed better water holding capability. Water holding rate and soaking time without decomposition litters and semi-decomposition litters had a visible logarithmic relationship(R>0.87), and absorption speed rate and immersion time had a power function relationship(R>0.94).(2) The average soil bulk density for different degrees of canopy coverage ranged from 1.36 to 1.49 g/cm³; total soil porosity, from 44.71% to 48.75%; effective water storage, from 395.33 to 831.00 t/hm², and soil stable infiltration rate, from 1.00 to 3.47 mm/min.

Abstract:To evaluate eco-hydrological functions of natural mixed forest of coniferous and broad-leaved trees, a research on the relationships among throughfall characteristics, spatial throughfall distribution patterns and rainfall in natural secondary mixed forest of Xiaolong Mountains was conducted by statistics and geostatistics. Data of 29 rainfall events with gross precipitation of 947.3 mm were collected. Total throughfall and throughfall ratio were 742.6 mm and 0.783 9, respectively. Throughfall increased with increasing rainfall, which can be well described by linear, logarithmic and Mitscherlich models. The more the rainfall amount, the higher the throughfall ratio was. Moreover, throughfall ratio increased with increasing rainfall and the relationship can be well described by logarithmic and Mitscherlich models. Variation coefficient of throughfall is negatively correlated with precipitation and the relationship can be described by Mitscherlich model. As rainfall increases, the ununiformity of spatial distribution of throughfall tended to decline and eventually approached a steady state. The spatial distributions of throughfall showed significant differences among different rainfall classes.

Abstract:Urbanization is an integrated process of regional population growth and socio-economic development. The most notable feature of urbanization is the urban expansion in space. Built-up area information was extracted from Landsat ETM⁺ images using decision tree classification method based on RULEGEN. Pearson's chi-square test and Shannon's entropy model were used to calculate the degrees of freedom and sprawl of urban expansion. Results show that the urban expansion had higher degrees of freedom and sprawl, moreover, it was imbalanced in different directions apparently in the resent 8 years. The degrees of freedom and sprawl in time spans declined and urban development tended to be compact.

Abstract:By using the related remote sensing data, statistical data and the four main carbon sources of fertilizer, agro-film, tillage and agro-machinery in 2010, a calculation of the carbon sources and sinks of agro-ecosystem in Guanzhong area was made in reference to the improved CASA (Carnegie-Ames-Stanford Biosphere) model, taking county (district or city) as a unit. The findings are as follows: (1) The total carbon absorption of the Guanzhong agro-ecosystem was about 6.44×10⁶ tons, with the high values of carbon absorption in June, July and August and the low values in December, January, February and March. The counties whose value of carbon absorption was more than 2.0×10⁵ tons were distributed in the north of Baoji City, west of Xianyang City, and middle and southwest of Weinan City. (2) The total amount of carbon emission of the Guanzhong agro-ecosystem was about 1.46×10⁶ tons. Fertilizer was the main carbon source, accounting for 89%. The regions whose value of carbon emission was more than 60 000 tons were distributed in the middle of Weinan City and mid-south of Xianyang City. (3) The total carbon sink of the Guanzhong agro-ecosystem was about 5 033 500 tons. The value of carbon sink more than 200 000 tons was centered in the northwest of Guanzhong area.

Abstract:Risk assessment of regional floods is the basis of flood disaster management. This paper takes Henan Province as the study area, where has suffered from frequent flood disasters. The main factors of flood disasters were first analyzed, and six indexes were chosen to build the assessment system of flood disaster risk from the aspects of dangerousness and vulnerability of flood disasters. The six indexes were absolute elevation, slope, average annual precipitation, river distribution, population density and the GDP density. The risk distribution map of flood disasters was obtained by using the functions of spatial analysis and overlay of ArcGIS software. Results showed that: (1) The risk of flood disaster decreased gradually from the south to north. (2) From administrative divisions, most areas of Xinyang City and some of the southern areas of Zhumadian City were in the high risk zone, Sanmenxia, Jiaozuo, Xinxiang, Hebi and Puyang Cities were in the low risk zone, and other areas were in the middle. risk zone

Abstract:The regionalization of soil and water conservation in Jiangsu Province is to make up for the deficiencies of the third level of national regionalization in Jiangsu Province and thus to manage soil and water conservation in the province more efficiently. This paper builds the index system of regionalization in accordance with the characteristics of Jiangsu Province, simplifies the factors' indexes by principal component analysis method, and draws, with the aid of GIS software, the distribution maps of the four major factors, namely nature, economy and society, land use, and soil and water loss. In the maps, the analytic hierarchy process(AHP) is employed to get the weight of each factor, and the conditional raster image overlay method is used to complete the superposition of the four factors with GIS software. The resulted raster images are reclassified and thus the quantitative division of soil and water conservation in Jiangsu Province is finished. This method can improve the efficiency and accuracy of the regionalization of soil and water conservation in Jiangsu Province and make up for the deficiency of subjectivity in the current regionalization.

Abstract:Using harmonic analysis, linear regression and Kendall's τ trend, based on the 10 day SPOT-VEGETATION NDVI from 1999 to 2010, we determined the beginning and end times of vegetation growth of each year, found the monotonic trend of vegetation coverage in growing season and interpolated the trend difference and growing season change of vegetation coverage for different vegetation types. Results are as follows: (1) From 1999 to 2010, the vegetation cover in China showed a progressively increasing trend as a whole. The annual variation of vegetation cover displayed the periodicity of 4 years steady growth and 1 year sudden decline. (2) On average, Kendall's τ trend for vegetation cover in growing season in China presented a continuous improvement, being 0.2873. The improved area with high persistence was mainly distributed in the region between 30°-40°N, and to the east of 105°E. (3) The vegetation cover was controlled by the change of latitude. The trend showing improvement was more significant and persistent at low latitude with high degree of biological diversity. The vegetation cover showed serious degradation in the ecological fragile zones like the Yellow River Delta and windy-sandy region, as well as in the rapid economic development areas like the Yangtze River Delta, Pearl River Delta and surrounding area of Lanzhou City.

Abstract:Adapting the fractal analysis method and raster DEMs of 25 m×25 m, this paper probes into the spatial distribution of landform patterns in the loess landforms of Northern Shaanxi Province by calculating the fractal dimension and stability coefficient of stream-network. Experimental results show that: (1) The complexity of fractal structure differs with various types of loess landforms, embodied mainly in diverse fractal dimensions and stability coefficients. Among these, loess hill and ridge regions possess the highest fractal dimension and the lowest stability coefficient, reflecting its most complex geomorphological structure in the area; loess tableland and scattered loess tableland regions rank the second; and the transitional regions between loess and desert, with rather smooth and simple terrain, present the lowest fractal dimension and the highest stability coefficient. (2) It is proved that the fractal parameter based investigation on the geomorphic features of loess landforms is feasible, and DEM datasets can play a critical and fundamental role in the process. The outcomes derived from fractal dimension show a strong correlation to geomorphic type or geologic structure to some extent. Moreover, more attentions should be paid on its geographical mechanisms.

Abstract:Risk assessment of debris flow in the Hongchun Gully of Shanyang County, Shangluo City, Shaanxi Province was studied. Risk assessment of debris flow under different rainfall conditions was carried out by employing the methods of quantitative calculation and data normalization. Intensity index was introduced to characterize the scale and potential ability of damage. Results show that the probability of debris flow occurrence is 100% when rainfall reaches 198.4 mm or more in 6 h. The level of debris flow risk is low when daily rainfall (r) reaches 37.19 mm; the level is middle when the r is 64.34 mm; the level is high when the r is 104.94 mm; and the level is very high when the r is 282.74 mm.

Abstract:Traditional monitoring on water quality is mainly carried according to the instantaneous concentration of pollutants in river, which is time consuming and labor cost. A method based on reuse of ion-exchange resin capsules was evaluated for continuously adsorbing ions in the Longhongjian stream discharged into the West Lake of Hangzhou City. Results showed that the recovery rates of reuse-resin capsule were greater than 95.91% for both NO₃^- and PO₄^3- , but the differences among treatments were not significant. The recovery rate of reuse-resin capsule for NH₄⁺ was greater than 100% in low concentration and 90% in high concentration. Significant correlations existed between resin capsule cumulative adsorption(RAQ) value and flow in all kinds of ions(R²=0.59, 0.47 and 0.50, respectively, p<0.05). Moreover, there was a significant positive correlation(R²=0.46, p<0.05) between RAQ of NO₃^--N and concentration of NO₃^--N and water flow, indicating that resin capsules can be used in water monitoring of nitrogen and phosphorus, especially NO₃^--N.

Abstract:Utilizing composite fuzzy evaluation model, selecting the characteristic evaluation index system of Nanjing City, and taking the year of 2009 as status quo, this paper evaluated the water resource carrying capacity(WRCC) of Nanjing City and obtained WRCC=0.365 4, which indicating that the water resource carrying capacity was at a low level and closed to the critical state of quasi-non-bearing. Then the paper predicted the relevant indexes of Nanjing City in 2020 with the grey prediction method and comprehensively evaluated the water resource carrying capacity of Nanjing City in 2020 reusing the composite fuzzy evaluation model. The result was WRCC=0.490 2, indicating that the water resource carrying capacity of Nanjing City will be still in the category and will be higher than that in 2009. Finally, the paper proposed some strategies to improve water resource carrying capacity of Nanjing City: (1) conserving water and reducing water consumption per capita; (2) controlling natural population growth rate; (3) regulating water structure and reducing water consumption of million GDP; (4) strengthening sewage disposal and reclaimed water utilization levels.

Abstract:By the theory that change of interlaced zone can indicate change of its environment, the moving split-window technique was applied to the judgment of interlaced zone located in Siertan wetland, Yanchi County, Ningxia Hui Autonomous Region to confirm the causes of wetland changes. Besides, certain indexes like vegetation survey, biodiversity index and rainfall were also used for the analysis of changes of interlaced zone. The technique was suitable for judging the interlaced zone boundary of the Siertan wetland and the relative appropriate window width was found to be 8 quadrats. Meanwhile, the judgement results for the interlaced zone in the Siertan wetland showed that the wetland had the largest interlaced zone width, which was far away from the center of wetland under better conditions in 2007. However, all the indexes decreased with the increase of time from 2008 to 2013, and the conditions of wetland became worst gradually. It was the construction of railway in 2008 that truncated stream water supply, which led to the shrunk of the wetland. Therefore, it is beneficial to protect surface runoff system in developing economy so as to prompt the permanent development of wetland. It can also provide new solutions and ideas to find and solve protection and improvement problems of wetlands in semi-arid region.

Abstract:This study selected the two common tree species of Pinus tabulaeformis and Acer truncatum in North China. The objective was to investigate the root system tensile strength, the overall root strength of root-soil composite and three root principal component contents (cellulose content, hemicellulose content and lignin content) of the two tree species for root diameters from 0.2 to 6 mm. The results showed that with the increasing root diameter, plant roots got a higher hemicellulose content and cellulose content and a lower lignin content, followed by decreased root tensile strength. Plant root tensile strength had positive correlations with cellulose content and lignin content and, negative correlation with hemicellulose content. Therefore, beyond the root structure influence, the cellulose content and lignin content of plant roots are the direct causes of differences between the soil-binding capacity.

Abstract:By taking the 22 barren hills for suitable afforestation in the Yuntai Mountains of Lianyungang City as the research object, 16 site factors were selected and divided into macroscopic and microcosmic factors to conduct site quality classification and assessment, respectively. In the end, the classification and assessment results were combined. Results are as follows: The 22 hills could be divided into five types. The main features of the first type, consisting of 2 hills, had a medium or superior thickness of soil layer, relatively fine site quality of macroscopic factor and medium soil quality; the second type, consisting of 4 hills, a medium or superior thickness of soil layer, relatively fine site quality of macroscopic factor and poor soil quality; the third type, consisting of 7 hills, a medium or inferior thickness of soil layer, relatively medium site quality of macroscopic factor and medium soil quality; the fourth type, consisting of 7 hills, a medium or inferior thickness of soil layer, relatively medium site quality of macroscopic factor and poor soil quality; and the fifth type, consisting of 2 hills, a very thin thickness of soil layer, relatively very poor site quality of macroscopic factor and medium soil quality. In summary, the site quality in the research area is not fine as a whole, and afforestation will be very difficult in the future.

Abstract:Five sizes of Salix psammophila checkerboard sand barriers (1×0.5,1×1,1×2, 2×2 and 2×3 m² in size; 15, 25 and 35 cm in height) in Mu Us sand land were set and the processes of sand flow near dune surface were analyzed in order to determine the protective benefits of the sand barriers. Results showed that the component of fine powder on dune surface increased obviously by Salix psammophila checkerboard. Compared with bare dune, the sand flux relative-intensity of checkerboard was reduced obviously. Combined with the local natural conditions and economic factors, the 2 m×2 m Salix psammophila checkerboard sand barrier is suitable for windbreak and desertification control in Mu Us sand land.

Abstract:In order to distinguish grey model or grey Markov model is more suitable for rainfall forecasting, grey model(GM), unbiased grey model and moving unbiased grey model were compared by taking the Caizhuang Reservoir in Shouyang County, Shanxi Province as the research object and using its 40 a rainfall data. The model with the highest precision slinding unbiased grey model was chosen and added to Markov model to generate grey Markov model and then compare it with grey model. Results showed that grey model gave a poor result for long-term prediction and highly fluctuant data. Therefore, based on grey model and Markov model, improved grey Markov model was established, which had their respective advantages and better predicting effects.

Abstract:The formation conditions of debris flow were analyzed and the seven key indexes of hill slope, elevation, hill surface roughness, rock stratum, distance to faults, seismic intensity of earthquake and land use type were chosen for evaluating the susceptibility of debris flow. A model of debris flow susceptibility was established by introducing logistic regression, and the evaluation and mapping of debris flow susceptibility were completed for the highways. Subsequently, this proposed method was applied in a case study carried out on the Sichuan-Tibet section of national highway G318. Analysis of debris flow susceptibility for the whole highway showed that 78.61% of the total study area was situated in debris flow-prone areas, including the canyon areas of Dadu, Lanchang, Jinsha, Nu and Palongzangbu Rivers. It is suggested that sufficient attentions should be paid in debris flow forecast and prevention in road reconstruction and line selection for new highway.

Abstract:After a brief introduction of the structure and flow characters of seepage wells, a mathematic model of coupled seepage and pipe flow is developed by adapting the equivalent hydraulic conductivity. By taking the Pantang water source region of Shenmu County as an example, the model is used to get allowable groundwater yield by the 3-D finite difference method of groundwater flow. Results show that newly added allowable yield from seepage wells is 92 400 m³/d, and the newly added allowable yield in dry season is 56 200 m³/d. By allowable yields of different fetching water methods, seepage well is better than tube well and radial collector well, which is not only suitable for water yield, but also easy for management. In the arid and semiarid area, seepage well is much better than other fetching water methods.

Abstract:To survey water pollution of the Xinli River in Bincheng District, 8 sampling sites were monitored using Vicia faba root tip cell micronucleus technique. The eight sampling sites were the reservoir outlet, Xixiezhuang Bridge, Huanghe No. 2 Bridge, Huanghe No. 5 Bridge, Huanghe No. 8 Bridge, Huanghe No. 12 Bridge, Huanghe No. 15 Bridge and Beiwaihuan Bridge. The water pollution status of the Xinli River was evaluated, combined with the investigation of sewage outfall number and apparent features of water quality. Results showed that pollution index(PI) for the four sampling points of the Huanghe No. 5 to No. 15 Bridges was greater than 3.50, belonging to serious pollution. The sources of river pollution were mainly the domestic sewage and industrial wastewater. The outfalls in this section accounted for 58.54% of the total discharge, with black sewage and obvious odor. Result from field investigation matched that from the micronucleus technique, and indicated that the Xinli River has been polluted seriously with the consequence of biological chromosome aberration, and pollution control of the Xinli River needs to be enhanced greatly.

Abstract:At three artificial rainfall intensities of 60, 90 and 105 mm/h, soil erosion on a slope of 20° was investigated using a three-dimensional laser scanner before and after rainfall. Results show that the amounts of runoff and erosion increased with the increasement of rainfall intensity, while the influence of increasing rainfall intensity on soil erosion is much larger than that on runoff. The calculated errors for the data of the three rainfall intensities using the three-dimensional laser scanner before and after rainfall were 0.872%, 9.349% and 4.495%, respectively, being less than 10%. At the same time, the eroded position and fragmentation could be observed intuitively. Using the three-dimensional laser scanner is able to calculate the volume and amount of soil erosion in a quick and accurate way, and observe the spatial distribution of soil erosion visually.

Abstract:In the engineering of side-slope ecological protection, there is a wide range of plants with different complex factors. It is difficult to take all the factors and their interrelations into account before determining the slope ecological protective species, due to big fuzziness of evaluation factors. Based on the fuzzy mathematics theory and multiple attribute decision-making method, the secondary fuzzy multiple attribute decision-making model for ecological protection species is constructed by means of field test, expert evaluation and a large amount of data. An attempt has been made to establish the model by the four evaluating indicators of stress resistance, functional performance, cultivate characteristics and growth characteristics in view of slope ecological protection effect. Further the four indicators are marked off sub-indexes. The fuzzy mathematics theory is used to evaluate indexes and their correlations for establishing one-level fuzzy multiple attribute decision-making model and then the secondary fuzzy multiple attribute decision making model. The decision-making model is employed to evaluate the slope ecological protection on an expressway in Northern Fujian Province which proves the proposed model effective and easy to operate. The analysis should be considered for the similar ecological protection engineering.

Abstract:By taking the economic fruit forest in Xingmu watershed of Jilin Province as the study object, the impacts of different fertilization pattern on soil physical and chemical properties were investigated through single component application and combined fertilizer application. Results indicated that: (1) Fertilizing treatments had some impacts on the increased amount of soil organic matter in 0-20 cm soil layer. The treatments, in order of the increased amount of organic matter, were organic and inorganic fertilizer and straw field(NPKOM), organic fertilizer and straw returning(OM), single-organic fertilizer(M), straw returning(O) and control(CK). Compared with the control treatment, the other treatments increased soil organic matter contents of 45%, 37%, 26% and 10%, respectively. (2) All the fertilizing treatments could improve soil permeability effectively, increase soil porosity and decrease soil bulk density. Straw returning was found to be the most effective treatment than the others(p=0.043). (3) Dynamic changes of total N, total P and total K not only had relations to the input and output amount of each element, but also had close relations to fertilizing methods and the background values of the elements. The variations of element contents became greater with the increasing background values. The combined fertilizer application had more significant effect than the single component application on the increases of total N and total P contents. This was mainly because of the increased nutrients input. The contents of total N, total P and total K showed the same change trend as soil organic matter content. The total K content was reduced differently among all the treatments.

Abstract:A traditional model of energetic ecological footprint was modified through adding artificial input indexes, unifying energy density and introducing energy-releasing/standard-coal coefficient, based on the assessment of the traditional model. Then, the sustainable development level of Nantong City, Jiangsu Province from 1996 to 2010 was measured with the modified model. Results show that: (1) The ecological footprint of Nantong City increased from 0.65 to 0.90 hm² per capita from 1996 to 2010, caused by the rapid energy consumption. (2) The ecological carrying capacity of Nantong City increased from 0.51 to 0.81 hm² per capita during the period, supported by the growth of agricultural and hydropower production, with a large potential of labor and capital input. (3) Nantong City has been in a state of ecological dificit, and the sustainability evaluation index was always larger than 0.5 from 1996 to 2010, which means that Nantong City was in an unsustainable state. In order to narrow the gap between ecological footprint and ecological carrying capacity, some measures can be put forward: guiding major industries and enterprises to save energy and exploiting new energy actively; increasing the investment in agricultural technology to improve agricultural production; and paying attention to investment in human resources and promoting technology and capital intensified economy.

Abstract:Drift potential is an important parameter to measure the strength of sand activities in an area. In order to understand sand particle migration in Tazhong area located in the Hinterland of the Taklimakan Desert, and to provide scientific reference for the prevention and control of sandstorm in the area, threshold sand-moving wind speed was revised to replace the previous empirical value through monthly surface soil moisture, and then the distribution of drift potential in the area was studied based on the meteorological data of Tazhong area from 2006 to 2012, including wind speed and direction. Results are as follows: (1) Sand-moving wind was mainly distributed in the ENE, NE and E directions. (2) The drift potential was mainly distributed in spring and summer. The seasonal resultant drift potential in spring was 71.3 VU and the resultant direction was 31°; in summer it was 59.7 VU and the resultant direction was 70.7°; and in winter, the resultant drift potential was least, only 1 VU. (3) The ratio of resultant drift potential to drift potential was relatively high in four seasons, showing that the wind regime was single in Tazhong area. (4) The drift potential was mainly distributed in the ENE, NE and E directions in four seasons.

Abstract:Green roof is capable of significantly reducing rainwater volume and purifying rainwater quality. It has become one of the important strategies to solve urban floods. This study investigated the ratio of runoff retention, effluent process and effluent water quality by building pilot scale facilities. Results from the experiment confirmed that the ratio of runoff retention is accordance with a certain periodic formula; the total runoff volume, the amount of previous reduction and later reduction have different linear correlations with the thickness of substrate layer; and green roof is capable of significantly reducing the concentrations of TN and COD, but the concentrations of NH₄-N and TP in runoff from green roof are higher relatively. Finally, this study recommends that the optimal range of the thickness of substrate layer is 10-20 cm by integrating the two aspects of hydrology and water quality.

Abstract:The three experimental sites of Shali(no grazing), Taoli(light grazing) and Wushenzhao(normal grazing) were selected according to grazing intensity to study the distribution characteristics of biological soil crust(BSC) for Artemisia ordosica community in Mu Us sandy land. The vegetation coverage, Artemisia ordosica coverage, BSC coverage, litter-fall coverage, fragmentation of BSC and its thickness in each experimental site were investigated for the fixed and semi-fixed sandy lands with Artemisia ordosica community. Results showed that the BSC coverage averaged 83.74% in fixed sandy land and 23.54% in semi-fixed sandy land. The BSC in semi-fixed sandy land was mostly the alga crust belonging to the initial developmental stage, while about half the BSC in the fixed sandy land was the mosses and lichen dominated crust. The coverage and thickness of BSC did not showed significant differences between grazing and light grazing in fixed sandy land, but normal grazing led to the significantly decreased coverage and thickness of BSC. The BSC in semi-fixed sandy land were more sensitive to distribution, even if a slight grazing disturbance would produce a considerable interference like normal grazing.

Abstract:Applying the monthly precipitation data of 22 stations in Liaoning Province from 1956 to 2011, the grads and years of droughts and floods were determined by Z index. Characteristics of droughts and floods nearby the sunspot extreme years were analyzed by frequency analysis method. Morlet wavelet analysis was made to analyze the changes of the Z index and sunspot. Results show that: (1) The frequency of droughts and floods was the same in the province in the past 56 years. The overall trend was from flood to dry, especially when entering in the 21 century. The drought frequency increased significantly, showing a drought phenomenon. (2) The sunspot number and the drought and flood phenomenon in Liaoning Province showed a negative relationship. The area appeared to be a drought year in sunspot peak and a flood year in sunspot valley. (3) There was a relationship between the drought and flood cycle and sunspot cycle in 7~11 years, and the change of sunspot number influenced the droughts and floods in Liaoning Province. In the next few years, sunspots will be near the active period and precipitation will decrease correspondingly.

Abstract:Soil aggregates of two karst soils(terra fusca and rendzina) and one zonal soil(red soil) with different soil organic carbon(SOC) contents were analyzed at 1.5, 2 and 2.5 mm sieving strength using AS200. Results show that the three soils, in order of decreasing mean soil weight diameter(MWD), were rendzina, terra fusca and red soil(p<0.05). With the change of sieving strength, particle size fractions of soil aggregates for terra fusca and rendzina were the same, while for red soil, the fraction changed from the dominance by large aggregates(>8, 8~5 and 5~2 mm) to middle sizes(5~2 and 2~1 mm). Red soil was the most easily destroyed soil, terra fusca was the second, and rendzina was the third, according to the mechanical classification. This implies that the mechanical stability of karst soil aggregates was better than that of red soil, and soil aggregate classification for the karst soils was directly affected by sieving strength. From the point of view of soil aggregates, the stability of the karst soils was stronger.

Abstract:The concentrations of heavy metals(Zn, Cu, Pb, Cd and Mn) are investigated in surface dusts of Bengbu City, Anhui Province. The geo-accumulation index and the Hakanson potential ecological risk index are employed to evaluate the pollution degree of heavy metals in the surface dusts and the level of potential ecological risks. Results show that the average contents of Zn, Cu, Pb, Cd and Mn in the surface dusts are 254.29, 85.64, 72.39, 2.31 and 535.86 mg/kg, respectively. The concentrations of the heavy metals are higher than their soil background values in Anhui Province. The evaluation results of geo-accumulation indicate that Cd is of partial heavy pollution, Zn and Cu are of partial mild pollution, Pb is of light pollution, and Mn is in clean level. All functional areas are in partial moderate pollution. Assessment results of the potential ecological risks indicate that Cd pollution is the most serious, beyond the strong ecological risk level in all sampling points. The other four heavy metals are in slight ecological risk. The sampling points in traffic, business, residential and industrial districts belong to very strong ecological risk degree and other sampling points are in strong ecological risk. After the removal of heavy metal Cd, various functional areas are in slight ecological risk. In general, the situation of surface dusts of Bengbu City is in a good ecological environment. However there is the very strong potential ecological risk for Cd.

Abstract:By Using EM₅₀ data collection system, soil moisture and temperature in the freezing and snowmelt periods were collected in the Juntanghu watershed situated on the northern slope of Tianshan Mountains, Hutubi County, Xinjiang Autonomous Region. The software, such as SPSS 19.0, Excel and surfer 8, was used to process the collected data. Meanwhile, change of surface soil moisture was simulated by soil temperature. The results indicated that there was a vertical distribution of soil moisture. In the freezing period, the minimum soil moisture was observed at the depths of 10, 32, and 48 cm; in the freezing period, the daily change of soil moisture was relatively little; and in the snowmelt period, the change was obvious, reaching a peak value at 17 to19 o'clock. The temperature of surface soil layer is able to simulate the soil moisture very well and the simulation has a better result both in temperature-rise and temperature-fall periods.

Abstract:In order to investigate the spatial distribution characteristics of soil nutrients in fruit+crop intercropping system, Malus pumila+Glycine max intercropping pattern, typical and representative in the loess region of West Shanxi Province, was studied and soil nutrients in the intercropping system of different ages were monitored separately for comparison. Results showed that:(1) In vertical direction, with the increasing soil depth, available K, available P and organic matters decreased, while total N increased at first and then decreased.(2) In horizontal direction, with the increase in the distance from tree row, soil nutrient contents in 4-year-old intercropping system and 6-year-old intercropping system showed a "W" type distribution, while the 8-year-old intercropping system had a "M" type distribution(except total N). Coincidently, all the extreme values appeared in the distances of 1.5, 2.5 and 3.5 m from tree row, and soil nutrient contents at the maximum points were significantly different from those at the minimum points(p<0.05).(3) Nutrients competition relations between fruit trees and crops changed gradually with the growth of the trees, and the competition of soil nutrients in the 8-year-old intercropping system was fiercest. In accordance with the distribution characteristics of soil nutrients in intercropping systems, nitrogen fertilizer should be the main fertilization, the distance of fruit tree and crops should be increased or planting crops in 8-year-old apple orchard should be prohibited.

Abstract:Based on the data collected from 40 plots in 4 sampling areas, the β diversities of plant community in artificial fencing area in Yanchi County were measured by applying binary and numerical data. Results show that: (1) Cody index(β_C), as well as β_CJ and β_CS derived from Jaccard and Sorenson similarity indexes(C_j and C_s), are able to reflect the community changes as the time gradient. (2) In the numerical data measure methods, to measure with the relative coverage and importance value as an index, the result is more reasonable. (3) According to the results of Morisita-Horn index for the numerical data, the long-term cultivating is not conducive to plant community succession, which makes the communities more vulnerable to environment impacts.

Abstract:A pot experiment was conducted to study the root morphological characteristics, root absorption area and nitrogen use efficiency of poplar seedlings under the four treatments of CK (neither urea nor vermicompost was applied), CF(100% of nitrogen was provided by urea), VC(100% of nitrogen was provided by vermicompost), and VC+CF(50% and 50% of nitrogen was provided by vermicompost and urea, respectively). Results showed that in comparison with the CF treatment, the VC+CF treatment significantly increased the total root length, root surface area, root volume and the number of root tips, but obviously decreased the root average diameter. The total root length in the VC+CF treatment was increased by 161.70%, 52.80% and 14.79% in comparison with the CK, CF and VC treatments, respectively. At the same time, the VC+CF treatment dramatically increased the total absorption area and active absorption area of root system. Not only the dry matter accumulation of root, stem and leaf, but also the absorption amount of nitrogen, phosphorous and potassium was remarkably enhanced by the use of VC+CF. Furthermore, the nitrogen use efficiency was 59.07% in VC+CF treatment, indicative of 57.35% and 27.09% increases over the CF and VC treatments, respectively. Additionally, the growth rate of aboveground was significantly faster than underground owing to the application of fertilization. However, in the VC treatment, less effect on root morphological characteristics, root absorption area and nitrogen use efficiency of poplar seedlings was observed than that in the VC+CF treatment. In conclusion, vermicompost co-applied with inorganic fertilizer had better effect on root characteristics and nutrient uptake of poplar seedlings.

Abstract:Spatial characteristics of soil physiochemical properties, soil microbial biomass carbon(SMBC) and soil microbial biomass nitrogen (SMBN) within 10 cm of soil surface in the Huainan reclaimed coal mine area were studied through field investigation and laboratory analysis. Results showed that contents of soil organic matter, nitrogen, phosphorus in cultivated lands(rape, wheat and vegetable greenhouse) were higher than those in woodland, but soil pH value was opposite. The land uses, in order of decreasing SMBC content, were vegetable greenhouse, rape, wheat, woodland and the control. Moreover, the SMBC content in vegetable greenhouse was significantly higher than the other cultivted land uses. The land uses, in order of decreasing SMBN content, were vegetable greenhouse, wheat, rape and woodland. The SMBN content in woodland was significantly higher than the other agricultural land uses. The soil microbial quotient was the highest in woodland, indicating that woodland was more suitable to soil microbial activities and soil organic matter accumulation. There was a significant correlation between the SMBC and SMBN, which further confirms that the SMBC and SMBN can be used as the sensitive factors to characterize the soil fertility.

Abstract:In order to survey the effect of human activities on soil environmental quality, 44 top soil samples were taken in three areas of Jiaozuo City. The single pollution index and the composite pollution index were used to assess the soil heavy metal pollution, and geostatistics method was applied to evaluate the spatial variation structure and distribution of four heavy metals(Cr, Cu, Cd and Pb) in top soils. Results showed that Cr was ranked first and Cd was ranked second in pollution index and overall standard rate, with the overall standard rates being 47.73% and 22.73%, respectively. The concentrations of Cr and Cd were highest in Shanyang District, next in Zhongzhan District, and lowest in Jiefang District. The concentrations of Cu and Pb were highest in Jiefang District, followed by Shanyang District, and lowest in Zhongzhan District. The concentrations of Cr, Cd and Pb were significantly correlated and likewise, Cu and Pb were significantly correlated. The four elements, in order of decreasing spatial variability, were Cd, Cr, Cu and Pb. Results from semivariance analysis showed that Cr had a relatively strong spatial-related variability; Pb, a medium spatial-related variability; and Cd and Cu, a relatively weak spatial-related variability. The distribution of Pb was shown as ring; Cu, as island; and Cr and Cd, as ribbon.

Abstract:The relationship between mountainous snowmelt runoff and temperature and rainfall was analyzed by using surface flow and climate data from the Juntanghu watershed, a typical study area for the central area of the northern Tianshan Mountains. Monthly temperature and precipitation data(1961-2010) observed from ten meteorological stations in the central area, including Wusu, Shihezi, Shawan, Manasi, Hutubi, Changji, Miquan, Xiaoquzi, Daxigou and Tianchi, were used for the Mann-Kendall trend analysis. The coefficient difference product curve was selected to analyze the relationship among temperature, runoff and precipitation. Hydrological modeling was conducted by using the soil and water assessment tool(SWAT). The parameters were calibrated by using the surface flow data(12 years) from the Hongshan Reservoir to predict the snowmelt runoff process of the Northern Tian Muontains in Xinjiang Wei Autonomous Region. Through changing the factors, such as average temperature and precipitation, results from sensitivity analysis demonstrated that snowmelt runoff was mainly affected by temperature and precipitation in snowmelt season. Moreover, from winter to spring, the effects of changing temperature were greater than those of precipitation on snowmelt runoff in the study area. This research leads to some potential contributions in understanding the mechanisms of snowmelt runoff in the warming central area of the Northern Tianshan Mountains.

Abstract:Based on GIMMS-NDVI synthesizing half month maximum every year and precipitation and temperature data from 1982 to 2006, changes of vegetation cover and spatial and temporal characteristics of its correlation with precipitation and temperature were studied using linear regression, Sen+Mann-Kendall analysis and correlation analysis methods. Results are as follows: (1) From 1982 to 2006, change of vegetation cover was obvious, with a changing rate of about 3%/10 a (p=0.19). Changes of vegetation showed a rising trend in most of regions with more surface water and a declining trend mainly in few arid desert regions. (2) The fluctuation of precipitation was obvious in Northwest China during the past 25 a and the overall trend showed a little decreasing. Interannual fluctuation of temperature was relatively small and its overall trend significantly increased. (3) From September to February next year, that is, from autumn to winter, the correlation between vegetation changes and precipitation was strong. From March to August, that is, from spring to summer, the response of vegetation to precipitation was a delay-dependent. The response of vegetation to temperature had one month lag in January, March and December and a significant correlation in other months. (4) Spatially, in the arid regions lacking surface water resources, the relationship between vegetation changes and precipitation was positive and between vegetation changes and temperature, negative. In the regions rich in surface water, the relationship between vegetation changes and precipitation was negative, and between vegetation changes and temperature, positive.

Abstract:Based on the data from the second class investigation of forest resources in the Liaoheyuan River Natural Reserve, grid quadrats sampling and CCA(canonical correspondence analysis) were used to analyze the relationship between the spatial distribution of forest landscapes in the Liaohe yuan River Natural Reserve and its environmental factors. (1) Overall performance of the forest landscapes is that the plantations are located in low-lying areas and natural forests, in high altitudes, which is the same as the distribution of the CCA ordination diagram. Monte Carlo test results show that elevation and slope are the main environmental factors affecting the differentiation of forest landscape patterns. (2) In the Natural Reserve, aspect, canopy density and soil thickness have very limited influence on the spatial distribution of forest landscape elements, and elevation is found to be the main factor to control the spatial distribution of forest landscape elements, followed by slope. Both indirectly control water, hot conditions affecting the distribution of stand species, thereby affecting the forest landscape pattern.

Abstract:Land degradation is one of serious ecological and environmental problems, and it directly affects the sustainable socioeconomic development of the Fenhe River basin. Based on the recent field data combined with related research literatures and basin environment characteristics, by means of ecological economic loss assessment methods, the paper studied the status and dynamic changes of land degradation in the Fenhe River basin, and accounted the economic loss of land degradation in 2010. The study showed that: (1) The economic loss by land degradation in the basin was up to 3.83×10⁹ yuan in 2010. The economic loss by soil and water loss was the most serious(accounted for 61.79%), which was equal to 2.37×10⁹ yuan. The economic losses by aeolian desertification and salinization were 2.31×10⁸ and 1.23×10⁹ yuan, respectively.(2) The economic loss by land degradation reached 0.77% of GDP in the basin. The upper reaches of the Fenhe River (accounted for 1.45%) were the key rehabilitation region. The economic loss by land degradation was equal to 14.58% of primary industry, which has affected the sustainable socioeconomic development of the basin. Economic loss of land degradation per capita in the Fenhe River basin was about 290.08 yuan, which restricted people's poverty relief, so control of land degradation should be strengthened.

Abstract:By field survey and soaking extraction in laboratory, the accumulation amount, water-holding capacity, water-holding rate and water-absorption rate of moss and litters were studied under two main natural forests(Picea wilsonii forest and P. wilsonii and Betula platyphylla mixed forest) in the Xinglong Mountains of Gansu Province in 2010. Results showed that: (1) The total thickness was 7.10~8.30 cm and the total accumulation amount was 24.66~30.69 t/hm² for moss and litters of two forests, but the thickness and amount of P. wilsonii and B. platyphlla forest were all greater than those of P. wilsonii forest. (2) The maximum water-holding rate of moss was obviously higher than that of litters, whereas the maximum water-holding capacity of litters was 11.15 times of that of moss. (3) The water-holding rate of moss and litters increased quickly at the beginning of immersion in water, increased gradually after 0.5 h, and tended to a stable value after 10 h. (4) The maximum retain capacity and the effective retain depth of litters were 10.27 times and 10.41 times of that of moss, respectively. Litter layer plays an important role in precipitation secondary distribution, as well as precipitation absorption and holding, and it is in the dominant position.

Abstract:The temporal and spatial characteristics of dynamic change of cultivated land in Jiangxi province was analyzed based on the cultivated land change and social economic data during 1990-2009. Meanwhile, the main driving force of cultivated land quantity change in Jiangxi Province was revealed using principal component analysis combining multivariate linear regression analysis. The results showed that cultivated land quantity change reduced at first and then increased; There were significant differences between different regions and the relative land change rate was strikingly different at different period; The main driving factors of cultivated land dynamic changes in Jiangxi Province included three main categories: economic growth, social development and agricultural science and technology advancement. Overall, the cultivated land quantity change had significant correlation with population, GDP, the social fixed assets investment, the three major industries, cultivated land output rate and farm machinery total power. There are two main driving factors in the first principal component which are economic and population. Moreover, the development of agricultural science and technology is the main factor in the second principal component.

Abstract:In order to investigate the soil improvement by degrade sea-buckthorn forest, soil properties in 0-60 cm soil layers under slightly, moderately and severely degrade sea-buckthorn forests were measured. (1) The concentrations of soil available P and K under the three degrade sea-buckthorn forests in 0-60 cm soil layers were larger than those under undisturbed slopes. (2) The increases were significant at the level of 0.05 for the concentrations of soil available N in 40-60 cm soil layer and soil available P in 0-20 cm soil layer under slightly degrade sea-buckthorn forest. The increase was significant(at the level of 0.01) for the concentration of soil available N in 20-40 cm soil layer under slightly degrade sea-buckthorn forest(The available N content increased from 14.23 to 22.39 mg/kg in 20-40 cm soil layer). The increases were also significant(at the level of 0.05) for the concentration of soil organic matter and soil available N in 20-60 cm soil layer under moderately degrade sea-buckthorn forest. Decrease was significant(at the level of 0.05) for the concentration of soil total N in 0-20 cm soil layer under severely degrade sea-buckthorn forest. (3) The increases of soil available P in 20-40 cm soil layer under the three degrade sea-buckthorn forests were in the following order: moderately degrade forest > slightly decayed forest > severely degrade forest. Soil available P in the 0-20 and 20-40 cm soil layers increased as the following order: slightly degrade forest > moderately degrade forest > severely degrade forest.

Abstract:Based on previous research results and field investigations of eroded landform on side slope of the Wuling tableland, in the Eastern Guanzhong Plain of Shaanxi Provinc remote sensing satellite images and other information are applied to analyze the development of eroded gully and loess collapse on the southern and northern edges of the tableland. The development conditions, spatial differences and influence factors for the eroded landform are discussed. Studies show that the river sill(8~30 m high loess cliff) on the southern edge of the tableland is the cave settlement zone, the eroded gully and loess collapse are affected by runoff and the cave zone on the edge with eroded gully presents the development of a small density but large scale on the eastern edge, but vice versa on the western section. On the river sill of the northern margin(30~90 m high loess cliff), the major development of the western part is characterized by massive loess collapsing, but the eastern part has small amount and long eroded valleys. The eroded landform development on side-slope of the Wuling tableland is mainly affected by geological structure, topographical conditions, new tectonic movement, loess lithology and structure, atmospheric precipitation and irrigation, as well as human activities. It has negative effects on inhabitation security, slope erosion, highland heritage conservation and the development and construction of the New Xi'an-Xianyang Developing District. Academia and relevant government departments should pay attention to the treatment and prevention of geological disasters on side-slope of the Wuling tableland.

Abstract:The formation mechanisms, movement processes, and dynamic characteristics of debris flow in the Western Sichuan Plateau, a high altitude and cold climate area, are unique because of the effects of landform, geological structure, ormation lithology and climate conditions. The areas of water convergence, provenance and accumulation of debris flows in the Sitongda Valley, Ganzi County, Sichuan Province are investigated by field investigation, mapping and sieving test to determine their formation mechanisms and dynamic characteristics. Results indicate that: (1) There are a big difference in elevation of basin terrain and a high ratio of channel slope, which provides terrain conditions for formatting debris flow. (2) Because drainage area of debris flows is wide, short-term rainstorm in plateau climate is able to provide adequate water supply. (3) Rivers develop in more than 3 000 m altitude areas, located in a climate change belt within cold temperate, subfrigid and frigid zones. Rock mass is fractured and soil structure is loose, caused by the climate condition of strong sunshine and large difference temperature that makes rock contrast weathering strong, as well as the influence of Xianshuihe fault zone. The fractured rock mass and loss soil structure provide rich source for the formation of debris flow.