Abstract:[Objective] This paper aims at exploring the relationship between the spongification degree and the quality of surface runoff, so as to provide guidance for the construction of sponge facilities alleviating current surface runoff pollution.[Methods] Jiaxing City is one of the pilot sponge cities in China and was taken as a study area, where 20 projects with different spongification degrees were selected as analysis units. Indicators were established reflecting the spongification degree, such as the type, quantity and layout of sponge facilities. Redundancy analysis, partial least squares method and Origin fitting equation were introduced in the study.[Results] ① Neither the water quality of residential area nor of public buildings areas attained class Ⅳ of surface water and secondary standards for sewage discharge. The water quality of the sponging-transformed area was generally better than that of the untransformed area. ② The area ratio of green space to effective impervious area(EIA) is the key factor affecting runoff water quality, of which suspended solids(SS), bichemical oxygen demand(BOD₅) and chemical oxygen demand(COD) are the mainly affected indicators. ③ In order to make the runoff water quality meet the requirements of sponge city construction, thresholds for the control of land use under different spongification degree should be different.[Conclusion] When EIA≈0, the proportion of green space should be no less than 31%; when EIA=0.04(TIA)^1.7 (TIA is the total impervious area), the proportion of green space should be no less than 38.5%; when EIA=TIA, the proportion of green space should be no less than 47%. The ratio of EIA should not exceed 9% under the current urban green space ratio standard(about 35%).

Abstract:[Objective] The development law of natural vegetation fires and their response to drought in Northeast China during 2002-2017 was studied, so as to provide scientific basis for regional fire management, fire risk level prediction and forest resources protection.[Methods] Based on the published available Moderate Resolution Imaging Spectroradiometer(MODIS) satellite products and the self-calibrating Palmer drought severity index(scPDSI)data, the seasonal and interannual characteristics of fire dynamics of natural vegetation in Northeast China were analyzed by using statistical methods, and the response law of fire dynamics to dry-wet conditions was explored.[Results] On seasonal scale, most forest and grassland fires occurred in spring and autumn, and grassland fire occurrence increased significantly in these two seasons. On inter-annual scale, forest fire occurrence decreased significantly at the rate of 18 times per year and their average burnt area increased faintly. Grassland fire occurrence showed an extremely significant upward trend at the rate of 36 times per year, and their average burnt area decreased faintly. There were linear and negative correlations between fire occurrence and scPDSI. But burnt area appeared exponential and negative correlations with scPDSI. Both average fire occurrence and average burnt area per individual fire showed an increasing trend with the deepening of drought.[Conclusion] Fire occurrence and burnt area per individual fire of natural vegetation could be increased under the condition of drought.

Abstract:[Objective] The variation characteristics of sandstorm weather frequency in Western Inner Mongolia Autonomous Region in the recent 54 years were studied in order to provide theoretical basis for its scientific prediction and prevention and treatment.[Methods] Through the methods of linear regression, 5-year sliding average, wavelet analysis, moving t test and Mann-Kendall, the changing trend, periodicity and mutagenicity of sandstorm day number of 24 meteorological stations in Western Inner Mongolia Autonomous Region were analyzed.[Results] ① In the recent 54 years, the frequency of sandstorm weather could be divided into high frequency period(1960-1975), rapid attenuation period(1976-1992) and low frequency period(1993-2013). The frequency of dust occurrence was 17, 9, 4 days per year, there were 31, 22, 13 years long periods and 5, 8, 1.5 years short cycles. ② There was an obvious mutation in the frequency of sandstorm around 1986. The linear decrement rate of 1976-1986 was 0.76 day per years, that of 1987-1992 was 1.4 days per years.[Conclusion] In the recent 54 years, the change of sandstorm day number in Western Inner Mongolia Autonomous Region showed a fluctuating trend, and there were obvious cyclical and mutagenic characteristics.

Abstract:[Objective] The influences of silt-laden inflow on ephemeral gully erosion process of bare slope and grassland slope were studied in order to provide theoretical basis for soil erosion control of ephemeral gully and lay a foundation for establishing a soil erosion model for loess areas.[Methods] A series of field rainfall simulation experiments were conducted on an artificial ephemeral gully(EG) to investigate the impacts of upslope inflowon runoff and erosion processes within the EG.[Results] The silt-laden inflow significantly increased the erosion of the bare slope with ephemeral gully by 15%~58%, and had no significant effect on the erosion of the grassland with ephemeral gully, indicating that grassland had significant benefits for reducing the erosion caused by the convergence. Under the experimental conditions, the sediment concentration of the bare slope and the grassland slope reached the maximum at the beginning of the runoff and then gradually decreased, and finally kept stable. However, the time required for the sediment concentration to stabilize under the silt-laden inflow increased. The silt-laden inflow accelerated the development of ephemeral gully, especially on the width and the depth of the ephemeral gully. While the grassland significantly slowed down the erosion of the ephemeral gully, especially the development of ephemeral gully under cut retarded. For the bare slope and grassland with ephemeral gully, the silt-laden inflow increased the flow velocity of the ephemeral gully, especially the average velocity of the grassland with ephemeral gully increased by 55%.[Conclusion] The amount of ephemeral gully erosion and the speed of ephemeral gully development on bare slope increased with increasing silt-laden inflow, while the impact on the erosion and development of the ephemeral gully on grassland slope was not significant.

Abstract:[Objective] The characteristics of soil anti-erodibility of different vegetation types were analyzed in order to provide scientific support for soil and water conservation and restoration of fragile ecosystem in the gorge of the karst plateau.[Methods] Field study was carried out in the karst plateau gorge region with five different vegetation types. Principal component analysis was used to identify the optimum indexes influencing soil anti-erodibility from 11 soil physical and chemical parameters and evaluate of the soil anti-erodibility.[Results] Compared with cultivated land, soil anti-erodibility of other vegetation types significantly enhanced, the content of water-stable macro-aggregate significantly decreased(p ≤ 0.05), soil clay content marginally increased(p>0.05), and percentage of soil dispersion and aggregate disruption significantly decreased(p ≤ 0.05). Results of principal component analysis showed that the content of clay, structural particle index, dispersionrate, agglomeration condition, water-stable macro-aggregate content and agglomerate destruction rate were optimal indicators for evaluating soil anti-erodibility. Based on comprehensive soil anti-erodibility index, the anti-erodibility was strongest for forest land, intercrop between forest and grass, natural grassland, grassland returned form farmland and cultivated land followed inorder.[Conclusion] The soil anti-erodibility was best under the natural recovery of Catalpa bungei forest. Increasing the area of Catalpa bungei forest was suggested to improve soil corrosion resistance, promote regional ecological restoration and enhance soil and water conservation.

Abstract:[Objective] The life history strategies of dominant species in patches and their responses to nutrient restriction, stoichiometry characterization of dominant species were studied in response to seasonal variation, which was expected to provid a scientific basis for the study of plant population succession and change process.[Methods] 3 typical patches, patch A(Stipa breviflora), patch B(Stipa breviflora+Astragalus melilotoides), patch C(Artemisia scoparia+Sophora alopecuroides+Cynanchum komarovii) were recognized and in which the dominated species were sampled, and its total carbon, total nitrogen, and total phosphorus contents were measured. Ratios of C:N, C:P, N:P were calculated and analysis of their variances were conducted. Stepwise linear regression analysis of stoichiometry of the patches was performed.[Results] The results showed that the changes of carbon(C), nitrogen(N), phosphorus(P) and their stoichiometry characterization of the dominant species in three patches were different during the growing season, and the seasonal variation characteristics were also different among the three patchesseason. The contents of C among the dominant species, and among the patches as well, had no significant differences. N content of S. breviflora was lower than than the values of other dominant species, which resulted to the significantly smaller level of the N content in patch A. P content of patch A increased along the growing season, while of patch C, it experienced an initial decrease and a succeeding increased. For patch A plants, there was no significant seasonal variation in C:N values, the values of C:P and N:P were significantly higher in spring than those in summer and in autumn. C:N, C:P and N:P values of the dominant species in patches B and C had significant differences. However, the seasonal variation was different:for patch B all values decreased except of C:N value, C:N, C:P and N:P values of patch C all increased first and then decreased.[Conclusion] The C, N, and P contents of three patches showed different correlations, patch A showed a defensive strategy, patch B showed a competitive strategy, while patch C showed a coexistence of competitive and defensive strategies.

Abstract:[Objective] The differences of soil erosion between micro-topography, microhabitat in clear-cutting site of the karst region were studied in order to provide suggestions for ecological restoration and control in clear-cutting site of the karst region.[Methods] Soil erosion monitoring method of pin was employed to monitor annually soil erosion in situ (differentmicro-topography, microhabitat) at a distance of 1 m×1 m within a research area enclosed by iron bars, and box chart and significance test were utilized to compare the difference of soil erosion between them.[Results] It was found that significant difference in the degree of soil erosion of different micro-topography and microhabitats in the study area. More specifically, depth of soil erosion of micro-topography manifested an overall scale of convex > flat > concave, while depth of soil erosion of microhabitat demonstrated an overall scale of stone-drain > stone soil surface > the side of stone > soil surface > rock tunnels. There was a significant correlation between micro-topography and soil erosion, while no significant correlation existed between microhabitats and soil erosion in groups, but stone-drain and soil surface were respectively correlate to each other significantly.[Conclusion] Ecological restoration and control should be carried out according to different micro-topography and microhabitat in karst mountain clear cutting site, and the key of control lied in the convex micro-topography, the microhabitat of stone-drain and stone soil surface.

Abstract:[Objective] The sediment yield of sub-watersheds in the real situation was analyzed, and the impact of single land use type on sediment yield was simulated in the control area of the Anxi hydrological station in the Xixi watershed of Jinjang basin in order to provide scientific support for the management of water resource in the basin.[Methods] HSPF (hydrological simulation program in Fortran) was applied to simulate the sediment discharge under three extreme land use change.[Results] ① R², Ens, and R_e were 0.849, 0.789, and -5.720% in the calibration period, respectively, and were 0.836, 0.837, and 10.790% in verification period, respectively, indicating the high precision of HSPF. ② The areas with higher annual average sediment yield are mainly distributed in areas with relatively high proportion of garden and forest. ③ From the perspective of yearly scale, comparing to the measured values in 2006, the sediment discharge increased 23.56% under garden scene, increased 20.39% under cropland scene, decreased 17.42% under forest scene. From the perspective of monthly scale, the sediment discharges of all the scenes during the wet period were greater than that of the dry period. The sediment discharge of the three landuse scene in May and July was:cropland > garden > forest, while sediment discharge in June and August was:garden > cropland > forest. ④ The unreasonable development of mountain tea orchard and the large proportion of sloping farmland and the lack of appropriate soil and water conservation measures are the main reasons for the increase of sediment discharge in the garden and cropland. The damage of forest and the unreasonable forest category structure are the reasons for the limited amount of reducing sediment discharge of forest scene.[Conclusion] HSPF has high precision in the simulation of sediment yield in watersheds; Garden plot and cultivated land could result in the increase of sediment yield, and forest land could result in the decrease of sediment yield while its amplitude was limited in the study area.

Abstract:[Objective] The effects of different herbaceous plants on soil nutrients and soil enzyme activities in the Amygdalus pedunculata were studied in order to provide a theoretical basis for vegetation restoration and ecological construction in the subsidence area of coal mines.[Methods] 6 kinds of forest and grass combined cropping patterns[Astragalus adsurgens+Amygdalus pedunculata(SC), Melilotus suaveolens+Amygdalus pedunculata(CC), Medicago sativa+Amygdalus pedunculata(MC), Onobrychis viciifolia+ Amygdalus pedunculata(HC), Coronilla varia+Amygdalus pedunculata(XC), Amygdalus pedunculata(CK)] were used as the research objects. The field plot test method analysis was used to determine the nutrient and soil enzyme activity index of 0-60 cm soil.[Results] ① The organic matter content of different configuration modes significantly increased compared with the control, which was characterized by MC > CC > SC > XC > HC > CK, the trends of total nitrogen, alkali nitrogen, available phosphorus, available potassium and organic matter were similar, and the MC, CC and SC was more obvious, and there was a much smaller increase in HC and XC; ② In addition to urease, the soil enzyme activity was significantly different among different compound configuration modes. The three modes of MC, CC and SC were significantly better than HC and XC; ③ Soil sucrase, catalase and alkaline phosphatase positively correlated with organic matter, total nitrogen, alkali nitrogen and available phosphorus. Urease positively correlated with available phosphorus, and soil enzyme activity and nutrients were closely related. It used to characterize soil improvement effects.[Conclusion] The three forest grass configurations modes of MC, CC and SC had improved the soil nutrient accumulation and enzyme activity. The above three modes should be used to carry out certain vegetation restoration in the subsided land of Yulin coal mine.

Abstract:[Objective] The flexural mechanical properties of six plant branches during non-growth period in midwest area of Inner Mongolia were studied in order to provide a scientific reference for the selection of the wind-resistant and sand-reducing plant species and their mixed configuration.[Methods] By YG(B)026H-250 fabric strength machine and self-made clamps, the branch bending test was carried out indoors, and the anti-folding forceand flexural strength of the branches of the six plants were compared, and the influence of the branch length and diameter on the mechanical strength index was analyzed.[Results] ① In the range of 0.5~2.5 mm diameter, the bending strength of 6 kinds of plant branches increased with the increase of diameter, while the bending strength decreased in power function with the increase of diameter; ② The breaking strength and breaking strength of Caragana korshinskii branches were the largest when the branch length was 60 mm in the range of 0.5~2.5 mm, the values were 51.700 N and 33.510 MPa, respectively, the breaking strength and breaking strength of Tamarix chinensis branches were the largest when the branch length was 80 mm, the values were 61.777 N and 30.821 MPa, respectively, and the breaking strength and breaking strength of Salix cheilophila branches were the largest when the branch length was 100 mm, the values were 62.237 N and 33.156 MPa, respectively.[Conclusion] The anti-folding force and flexural strength of 6 plant shoots were inconsistent with the increase of diameter and length of shoots during non-growth period, indicated that the effects of anti-folding force and flexural strength of shoots were different in plant species and branch length. It also proved that the combination of multiple trees should be the optional choices to realize the soil and water conservation function especially in the ecological restoration.

Abstract:[Objective] The spatial and temporal variation characteristics and disasters of rainstorms in Gansu Province in recent 50 years were studied in order to provide a scientific basis for the rainstorm climate prediction, disaster prevention and reduction in this area.[Methods] Based on the daily precipitation data of 29 meteorological stations in Gansu Province from 1968 to 2017, linear trend, Mann-Kendall abrusttest test, Morlet wavelet transform and other methods were used.[Results] ① Longdong area was the high-frequency center of heavy rain in Gansu Province, followed by Longnan, and the lowest in Hexi Corridor and Longxi area. ② Rainstorm days in Gansu Province showed an upward trend in the recent 50 years and increased significantly in July, but decreased in May. ③ The rainstorm in Gansu Province experienced less-less-more-less-less progress in the recent 50 years. Most of the interdecadal variations, except for the 1980s and 1990s, were greatly influenced by the autumn rainstorm, the other years were greatly influenced by the summer rainstorm. ④ The oscillation periods of rainstorm days and rainstorm volume in Gansu Province were almost the same. There were two short periods of 8-year and 3-year, the 8-year cycle of rainstorm days was more obvious than the 3-year cycle, and rainstorm volume was the opposite. During the study period, there was no abrupt change in the rainstorm days. The rainstorm volume was an abrupt change point in 1977. ⑤ The change of rainstorm in recent 50 years might be due to global warming and the intensification of East Asian monsoon.[Conclusion] The increase of rainstorms in Gansu Province in recent 50 years caused more floods and droughts. It was necessary to strengthen the rainstorm monitoring and disaster prevention and relief work in Gansu Province.

Abstract:[Objective] The water-holding efficiency of different vegetation litter was studied in order to provide a theoretical basis for vegetation restoration and soil erosion control in loess hilly region.[Methods] The hydrological effect of the litter layers of four typical shrub woodlands (Caragana korshinskii, Hippophae rhamnoides, Sophora viciifolia and Periploca sepium) were studied, using indoor immersion method.[Results] ① The stock of the litter surface in Hippophae rhamnoides was the largest(1.048 kg/m²). The amount of litter in the soil of Caragana korshinskii was the largest(0.769 kg/m²). In addition, the litter in the soil accounted for 20.15%~55.92% of the total accumulated amount of litter, and the litter in the soil of Caragana korshinskii and Sophora viciifolia was higher than that of the surface litter. ② The water-holding capacity of litter on the surface and the litter in the soil showed a very significant logarithmic function with the immersion time(R² ≥ 0.745, p<0.01). The water-holding capacity of surface litter could reach 40% of the maximum water holding capacity in 5 min, and there was a significant power function relationship with the maximum water holding capacity(R²=0.38, p<0.01), that was to say, the maximum water-holding capacity of the surface litter could be fitted by the water holding capacity of 5 min, but this rule was not found for the litter in the soil. The water-holding capacity of the litter in the soil was significantly higher than the surface. The surface litter of the Periploca sepium had the highest effective water-holding capacity(2.13 g/g). What's more, the litter in the soil of Caragana korshinskii had the highest effective water-holding capacity(1.90 g/g). ③ The surface litter of Hippophae rhamnoides had the largest effective retaining content of 21.16 t/hm². The litter in the soil of Caragana korshinskii had the highest effective retaining capacity(10.01 t/hm²). The correction coefficient of litter retaining content in soil varied from 0.18 to 0.42.[Conclution] The litter in soil could not be ignored, the mixed amount of litter accounted for more than 1/5 or even 2/3 of the total volume of litter. The total effective water-holding capacity of Caragana korshinskii was the largest, while under the influence of litter type and accumulation amount, the total holding capacity of Hippophae rhamnoides was the largest, with strong water conservation and soil and water conservation functions.

Abstract:[Objective] The difference of soil infiltration performance at different altitudes and its influencing factors in Hengshan Mountains were studied to provide ideas and methods for the reseraches of large-scale soil infiltration.[Methods] Using point-source infiltration method test at 9 points in different altitude areas of Hengshan Mountains.[Results] From the point of view of infiltration rate, the infiltration rate changed significantly and the stable infiltration rate increased gradually with the rising of elevation (top > hillside > foothill). From the beginning of infiltration to stable infiltration, the infiltration rate decreased by 50%~86%, and the infiltration process showed a certain regularity. The initial infiltration rate was very large. With the process of infiltration, the infiltration rate decreased rapidly in the first 10 minutes and continued to decrease slowly in the succedent 10~30 minutes. Finally, it got stable after 30 minutes. There are many factors affecting soil infiltration performance. In this experiment, the stable infiltration rate had a significant positive correlation with the content of>0.25 mm water-stable aggregates and with the altitude, but had a low correlation with organic matter, soil bulk density and texture. Kostiakov model, Philip model and Horton model all had more than 0.95 determinant coefficients R² in each test site, which can fit the infiltration rate of Hengshan Mountains test site well. The parameters A of Philip model were negative, meaning that their physical meaning is not clear. Therefore, that model has some limitations in fitting the infiltration rate of Hengshan Mountains.[Conclusion] Horton model can reflect the characteristics of stable infiltration rate at different altitudes (top > mountainside > foothill). Kostiakov model can better reflect the variation characteristics of infiltration rate (foothill > top > mountainside). It also shows that point-source infiltration method is feasible to measure mountainous infiltration.

Abstract:[Objective] The long-term effects of Pinus sylvestris var. mongolica afforestation on soil particle composition and carbon sequestration in Mu Us Sandy Land were studied in order to provide a scientific basis for comprehensive evaluation of ecological environment effects of vegetation restoration.[Methods] Artificial Pinus sylvestris with different shelterbelt planted years(21 years, 36 years, 56 years) and shifting sandy land were selected as sampling sites on the southeastern margin of the Mu Us sandy land, and 0-30 cm soils were collected and analyzed layer by layer to explore the long-term effects of plantation construction on soil particle composition and carbon conteunder different particles grades in semi-arid desert areas.[Results] With the increase of planting years, the soil particles became finer gradually, and content of fine particles in the surface layer(0-5 cm) were higher than beneath layers(5-30 cm). The contents of soil organic carbon(SOC) and inorganic carbon(SIC) increased significantly after shelterbelt construction, and the highest values were 4.90 times and 4.32 times of the shifting sandy land, respectively. The effect of shelterbelt age on SOC content and SOC density(SOCD) was more significant than SIC content and SIC density(SICD). Compared with the shifting sandy land, SOC and SIC contents of each particle size increased most obvious in the shelterbelt planted for 56 years, and the increase of amplitude was largest in fine sand. There were significant linear correlations between organic carbon content of aggregate and silt-clay and total soil organic carbon content, respectively(p<0.01). The contribution rates of organic carbon in coarse sand and silt-clay to total organic carbon, inorganic carbon in silt-clay to total inorganic carbon were significant, respectively(p<0.05).[Conclusion] The contents of soil aggregates and silt-clay particles and soil carbon sequestration capacity were significantly improved with the increase of Pinus sylvestris shelterbelt age.

Abstract:[Objective] The impacts of precipitation and human activities on runoff in Yuanshui River Basin and its cause were studied in order to provide scientific basis for the water utilization of Yuanshui River basin.[Methods] By using cumulative anomaly method and sliding t test, the trend and mutation test of precipitation and runoff series in recent 55 years in Yuanshui basin were carried out. The contribution rate of precipitation and human activities to runoff change in Yuanshui River basin was calculated by double cumulative curve method.[Results] In addition to Anjiang Station, which was obviously influenced by human activities, its contribution was 60%. In the period of variation Ⅰ(1989-2003), precipitation had greater impact on runoff than the contribution rate of human activities. In the period of variation Ⅱ(2004-2014), the contribution rate of human activities increased significantly and gradually became the main driving factor of runoff change.[Conclusion] In recent 55 years, the influence of human activities on runoff in the Yuanshui River basin had been increasing. The contribution rate of human activities in the lower reaches of the Yuan River basin had increased the most.

Abstract:[Objective] The effects of slope length on the runoff and sediment yield of the engineering accumulating body were studied in order to provide theoretical basis and technical support for the reasonable prevention and control of soil and water loss in engineering accumulations in production practice.[Methods] Three slope (24°, 28 °, 32 °) and five slope length (4,8,12,16,20 m) were selected for simulated field test of runoff erosion on exposed engineering accumulating body.[Results] The runoff rate and sediment yield of 24°, 28° and 32° slopes fluctuated with the increase of slope length. The correlation between the runoff rate and the sediment yield of the 4 m and 8 m slopes was significant, the correlation between the runoff rate and the sediment yield of the slope at 12, 16 and 20 m was only significant at 32°. Cumulative flow rate and cumulative sediment yield had a power function relationship with slope length. The cumulative sediment yield and cumulative yield had a linear function relationship.[Conclusion] The influence of slope length on slope runoff rate and sediment yield was different due to different slope; cumulative runoff and sediment yield increased with slope length.

Abstract:[Objective] The optimal replacement and transformation modes were analyzed and evaluated in order to provide theoretical basis and technical support for the restoration of degraded forest stand in saline land of the Yellow River delta.[Methods] Two kinds of forest stand in the Yellow River delta saline land degraded Ulmus pumila and Populus×xiaozhuanica were selected as the research objects. The growth, soil and vegetation benefits of the two degraded stands and their different replacement and transformation modes were studied by using the methods of field investigation and laboratory analysis and measurement.[Results] ① There were great differences in canopy density and forest preservation rate between the replacement and transformation modes of the degraded U. pumila and P.×xiaozhuanica, but mixed forest was better than pure forest on the whole, and the species with strong salt tolerance were better than those with poor salt tolerance. ② The different replacement and transformation modes of the decaying U. pumila forest and P.×xiaozhuanica forest had been improved in soil physicochemical properties, and both of them could improve soil conservation and effective conservation. The pH value and salinity of the soil were decreased by different alternation modes. The soil organic matter and nutrient status of the two degraded stands were improved greatly after being replaced and transformed into different modes. ③ The vegetation of different stands was different, but in general, the habitat of the replacement and transformation mode was better than that of the degraded forest stands, and the plants with low salt tolerance appeared, and the vegetation types increased, but with the increase of stand canopy density, shade plants appeared, and the drought and salt tolerant plant species decreased.[Conclusion] Based on the analysis of forest stand growth, soil and vegetation of two different modes of forest stand replacement and transformation in the two degraded forest stands, in the replacement and transformation of degraded U. pumila stands, the mixed forest mode of Salix americana and Robinia pseudoacacia and U. pumila was the best, followed by pure forest of U. pumila and pure forest of Robinia pseudoacacia, while the pure forest mode of S. americana was not suitable. Among the two modes of replacement and transformation of P.×xiaozhuanica degraded forest, U. pumila forest was the best, S. cheilophila pure forest was the worst.

Abstract:[Objective] The erodibility factors of different soil types were calculated in order to provide scientific basis for quantitative evaluation of soil erosion and dynamic monitoring of soil erosion.[Methods] By collecting data from runoff plots in the whole country and using the data selection criteria. The K factor value of the main kinds of soil in China was calculated by plot data and evaluated the applicability of the Wischmeier's and the EPIC model in the country.[Results] The K value of the main kinds of soil in China ranged from 0.000 8 to 0.070 5(t·hm²·h)/(hm²·MJ·mm). The K value of black soil, cultivated loessial soil and cinnamon soil were higher, while it was lower in the red earths and purple soil. In the whole country, there was a large deviation between the K factor values estimated by the models and the observed data, but the revised empirical model could be used properly in the black soil region of Northeast China.[Conclusion] The K value correcting to the unit runoff plot was calculated based on the data of the runoff plots and references throughout the country. The K value varied greatly over space, it showed that there had a decreasing tendency from the north to the south. In order to obtain a more accurate K value and establish relevant empirical formulas, it was necessary to further strengthen the monitoring points management and the accumulation of long-term observation data.

Abstract:[Objective] The interaction of plants on the removals of N and P efficiency by ecological floating bed was studied to provide a theoretical basis for the large-scale construction of Nanhai Lake wetland in the later period.[Methods] Under the condition of natural open water, three kinds of water-stained plants, Scirpus validus, Lythrum salicaria, and Cyperus alternifolius, which are suitable for growth in the north, were selected as floating bed plants, and high-density polyethylene hollow plastic substrates were used as plant carriers, to establish two kinds of floating bed systems of single planting and mixed planting in the Nanhai Lake Wetland Reserve for 90 days of water treatment to study plant growth characteristics and floating bed purification effects.[Results] At the time of harvest in October, the number of tillers of Scirpus validus and Cyperus alternifolius in the mixed floating bed reached 26 and 30, respectively, and the biomasses (fresh weight) were 1.43 kg/plant and 1.98 kg/plant, respectively. The cumulative amount of Scirpus validus grass floating bed N was the best, reaching 110.6 g/m², and the water body TN removal rate was 34.9%. The cumulative amount of mixed floating bed P was the best, reaching 26.02 g/m², and the water body TP removal rate was 43.3%.[Conclusion] The interaction of plants can promote the tillering of plants, but it does not change the N and P absorption capacity of plants. The accumulations of N and P in plants were greatly affected by biomass, and the individual accumulations for the three plants in mixed floating bed were greater than those in single floating bed. The mixed floating bed can be used as a floating bed for the restoration of eutrophic water in Nanhai Lake.

Abstract:[Objective] The effects of artificial Hippophae rhamnoides forests on soil quality improvement under different ages were studied in order to provide a basis for scientific evaluating ecological construction, restoration and reconstruction of Artificial Hippophae rhamnoides forest in sandstone area.[Methods] Taking the Hippophae rhamnoides forests of different ages in typical sandstone area of Dalat Banner of Inner Mongolia as the research object, and using the gray correlation analysis, the soil physical properties(soil water content, soil bulk density, total soil porosity, specific gravity of soil, soil capillary porosity, soil non-capillary porosity, soil saturated water holding capacity and soil maximum capillary water holding capacity) of 0-40 cm soil layer of Hippophae rhamnoides forest from 1 a to 7 a on the sunny slope of the slope were measured. The soil improvement effect of Hippophae rhamnoides forests on sandstone soil under different forest ages was analyzed with surrounding barren slope as control(CK).[Results] Soil water content and total soil porosity increased with the age of Hippophae rhamnoides forests, decreased with soil depth, but soil bulk density was opposite; Hippophaer hamnoides of different forestages could enhance soil water holding capacity, and the water holding capacity of Hippophae rhamnoides of 4~7 a was greater than that of Hippophae rhamnoides of 1~3 a.[Conclusion] The construction of artificial seabuckthorn forest in sandstone area is beneficial to soil improvement. Hippophaer hamnoides of different forestages mainly affected soil improvement in layers of 0-10 cm and 10-20 cm.

Abstract:[Objective] With respect to the regional phenomenon of ecological environment vulnerability and single stratification of landscapes in loess hilly region, the ideas and ways of landscape reengineering and renovating of check dam based on the eco-design theory were studied in order to provide new thoughts and references for environmental governance.[Methods] The landscape renovation design was located in north of soil and water conservation demonstration garden in the Xindian watershed of Suide County, Shaanxi Province, based on the investigation and analysis of the current status, the researches which focused on the renovative ways of the construction wetland project design were conducted.[Results] The ideas about landscape reengineering and renovating of check dam in the arid area were put forward, simultaneously, integrated implemented measures of free water surface constructed wetlands project for the arid area should be considered and guided by the ecological design theory.[Conclusion] Environmental governance in the arid area gullies should comprehensively consider soil and water conservation function, ecological landscape construction and tourism function, and ensured to produce the best ecological performance, economy performance and social performance by implementing the measures of low impact development.

Abstract:[Objective] Taking the typical sandy land in the northern part of Zhenglan Banner of Inner Mongolia Region as an example, the best image fusion method in the sandy area by using the domestic high-resolution satellite(GF-2) image was studied in order to provide technical support for the study of the image fusion method in the sandy area.[Methods] 1 m Pan spectral image and 4 m multispectral image of GF-2 were fused by HSV(Hue, Saturation, Value), Brovey, Gram-Schmidt and PC(principal components); And the four statistical methods, including average gradient, joint quantity, relative deviation and standard deviation were selected to evaluate and analyze the effect of fusion.[Results] The above four fusion methods could significantly improve the four fold spatial information discrimination of the multi-spectral image in the study area, preserve the original multi-spectral information of the image, and enhance the resolution ability of the image information. Among them, Brovey fusion method had the smallest relative deviation, PC had the least obvious fusion effect, while HSV fusion method had the largest joint quantity and average gradient, and it had the best image fusion effect.[Conclusion] HSV fusion was the best method of image fusion in sandy area. It could provide to clear spatial and spectral image data for visual interpretation of sandy areas.

Abstract:[Objective] The spatial and temporal distribution characteristics and influencing factors of the water supply in Dalian City of Liaoning Province were studied in order to provide visual evaluation results and a basis for the development and protection of water resources.[Methods] Based on the InVEST model, the characteristics of rainfall, air temperature, potential evapotranspiration, actual evapotranspiration, and land use in Dalian City from 1980 to 2015 were investigated. Quantitative estimation of spatial and temporal distribution characteristics and causes of water supply in Dalian City from 1980 to 2015 were also analyzed.[Results] ① From 1980 to 2015, the average annual precipitation and potential evapotranspiration of Dalian City did not decrease significantly, the average annual temperature and drying coefficient increased significantly, and the annual actual evapotranspiration decreased significantly. ② The area of cultivated land and woodland decreased, the area of urban construction land transferring from increased, and the area of other land types had less change. ③ The average water supply was 226.36 mm and the total water production was 2.70×10⁹ m³. It showed a trend of decreasing form the northeast to the southwest. The annual water production in Zhuanghe City was the largest, reaching 1.10×10⁹ m³.[Conclusion] The change of water supply was resulted from both climate change and land use. Climate change was the main driving force for water supply change, and land use change had some slight effects on the increase of water supply.

Abstract:[Objective] To gain insight the trends, evolution and the current status of coastal ecological restoration research, a comprehensive analysis of the coastal ecological restoration was conducted.[Methods] A total of 866 papers about coastal ecological restoration in the database of Web of Science from 1996 to 2019 were used as data sources. Keywords time zone evolution and literature co-citation network were conducted using CiteSpace 5.3 analysis software.[Results] ① Research on coastal ecological restoration could be divided into three stages:initial period, stable growth period and expansion period. Keywords such as "ecosystem service", "environmental reclamation" and "climate change" had become the high-frequency words in recent years; ② The relevant research mainly focused on three aspects:coastal ecological environment basic research, ecological restoration engineering and ecological management.[Conclusion] Coastal landscape changes caused by reclamation, scientific assessment of coastal ecosystem services and the impact of "blue carbon" on global climate change would become a research hotspot in the future.

Abstract:[Objective] Two cognitive tendencies were implied in the study of land carrying capacity(LCC), they are, the limiting factor theory and the multifactor comprehensive theory. Based on the methodology review of these two types of research, two laws of LCC were refined, which could enrich the theoretical system of carrying capacity and serve the social practice better.[Methods] Methods of documentation and comparative analysis were employed.[Results] In the lights of the ideas of "the Law of the Minimum", "the Principle of Limiting Factors" and "the Cask Theory", we presented the first law of LCC, which reveals the fact that in a relatively closed man-nature system, the LCC depends on the carrying capacity of the limiting factor exclusively. This law is mainly applied to such situations as "How many people can the Earth carry?", "How many people can a country support?" or "What is the supporting capacity of scarce resources in a particular region?". Under the guidance of holism and systematology, the second law of LCC says that in an absolute open man-nature system, the LCC is determined by the synthesizing effect of multiple factors. Situations like "the amount of regional comprehensive carrying capacity" and "the index of regional comprehensive carrying capacity" can adopt this theorem.[Conclusion] Each law explains different connotations of LCC, which means the laws are appropriate for various circumstances respectively, and can meet different research purposes. When applying the two laws of LCC later, such problems as the maximum attribute contained in the LCC, or the relationship between the spatial scale and the laws need to be studied in addition to the prerequisites.

Abstract:[Objective] The effects on the hydrological and ecological environment, after the needle-leaved trees inserted into the the broad-leaved forests at steep slope of the dam area, were studied in order to provide a scientific basis for afforestation and improvement of hydrological and ecological environment.[Methods] Three typical vegetation types in the study area were used as research objects, and the hydrological and ecological effects of litter layer and soil layer were quantitatively determined by indoor immersion method and ring knife method.[Results] ① The accumulation of litter was in the order of Pinus tabuliformis-Apricot mixed forest > Mountain apricot forest > Spiraea shrub; the effective storage capacity was in the order of Pinus tabuliformis-Apricot mixed forest > Mountain apricot forest > Spiraea shrub. There was a good functional relationship between the water holding capacity of litter and the water holding rate of litter and the water immersion time. ② The effective water holding capacity of the 3 planting types was Pinus tabuliformis-Apricot mixed forest (69.00 t/hm²)>Mountain apricot forest (60.87 t/hm²)>Spiraea shrub (55.60 t/hm²); The initial infiltration rate of Pinus tabuliformis-Apricot mixed forest was 29.78 mm/min, and the minimum infiltration rate of Spiraea shrub was 22.38 mm/min. The infiltration rate and infiltration time of three planting types had better power(R²>0.97).[Conclusion] Combining the water holding capacity of the litter layer and the soil layer, it could be seen that the water conservation function of the Pinus tabuliformis-Apricot mixed forest was the strongest among the three different vegetation types, while the water conservation capacity of the Spiraea shrub was the worst. It indicated that broad-leaved forest transformation had enhanced the water conservation capacity of forests and improved the hydrological and ecological environment of forests in the steep slope area. Therefore, from the perspective of enhancing water conservation, it was recommended to introduce appropriate density of Pinus tabuliformis in shrubs and broad-leaved forests in the area to improve the hydrological ecological environment of the area.

Abstract:[Objective] The changes of root exudates of Koelreuteria paniculata and Cinnamomum camphora under phenanthrene(PHE) were analyzed in order to provide scientific basis for screening tree species resistant to polycyclic aromatic hydrocarbons pollution and further phytoremediation of polycyclic aromatic hydrocarbons pollution.[Methods] Three concentrations of phenanthrene[L₀(CK, 0 mg/kg), L₁(100 mg/kg), L₂(1 000 mg/kg)] were set up in this experiment. Total organic carbon(TOC), total carbon(TC), total nitrogen(TN) and root activity in root exudates of Koelreuteria paniculata and Cinnamomum camphora trees were determined by pot experiment.[Results] ① With the increase of phenanthrene concentration, the contents of TOC and TC in root exudation of Koelreuteria paniculata and Cinnamomum camphora decreased, while the contents of TN increased first and then decreased with the increase of phenanthrene concentration; ② With the increase of phenanthrene concentration, the total absorption area and active absorption area of roots of Koelreuteria paniculata and Cinnamomum camphora showed a downward trend. ③ Under the three treatments, the contents of TC, TOC and TN in root exudates of Koelreuteria paniculata were higher than those of Cinnamomum camphora, and the total and active absorption areas of Koelreuteria paniculata root were also higher than those of Cinnamomum camphora.[Conclusion] By comparing root exudation and root activity of Koelreuteria paniculata and Cinnamomum camphora under phenanthrene stress, it showed that Koelreuteria paniculata had better tolerance to phenanthrene than Cinnamomum camphora.

Abstract:[Objective] The evapotranspiration pattern, evolvement characteristics and water demand laws of ecosystem in typical agro-pastoral areas were studied to provide scientific basis for regional ecological management and water resources management.[Methods] Yanchi County of Ningxia Hui Autonomous Region was taken as an example, four-phase of Landsat remote sensing data and meteorological data from 2000 to 2017 were selected, and the daily evapotranspiration in different periods of the county was retrieved by using the SEBAL model, and the land use type data was analyzed and studied in the same period.[Results] ① The daily evapotranspiration at the beginning of the fall increased from 0.89 mm/d in 2000 to 1.71 mm/d in 2017, with an increase of 92.1%, designating that it had an increasing trend. ② There was a strong spatial heterogeneity in the daily evapotranspiration, and it was generally high in the south and low in the north, especially in the southeast loess hilly region, it was the highest. The annual growth rate of the past 17 years' evapotranspiration showed a characteristic of high in the south and low in the north, but there were large differences in the spatial pattern of annual increase in different periods. ③ There were differences in the evapotranspiration of different types of land. The average evapotranspirations of arable land, woodland and grassland were 1.42, 1.33, and 1.27 mm/d, respectively, but the largest annual increase in evapotranspiration was grassland. ④ The total amount of ecological water demand in Yanchi County and the amount of ecological water demand in various areas were increasing. The order of ecological water demand from high to low is grassland, arable land and woodland. However, the per unit ecological water requirement was the highest for arable land, and the smallest was of grassland. The shares of ecological water requirements of arable land and forest land in the total ecological water needs in the past 17 years was declining, while the proportion of grassland ecological water needs was on the rise.[Conclusion] Under the background of the intensive ecological management project in Yanchi County, the regional evapotranspiration increased significantly, the water demand of vegetation ecosystem increased obviously, and the evapotranspiration and water demand structure of different areas also changed.

Abstract:[Objective] The impacts of Tangpu reservoir development and management activities on watershed land use and eco-environmental effects were studied in order to provide reference for pollution prevention and operation management of water source reservoirs.[Methods] Through ENVI remote sensing interpretation of the land use status of the reservoir basin in five different periods, the LUCC transfer matrix and ecological value index of the reservoir basin were analyzed. Based on the spatial analysis of ArcGIS, the main pollution monitoring and control areas in the basin were identified, and the trend of the ecological value index of the basin after the relocation of existing residents in the reservoir basin was predicted.[Results] The main LUCC in the basin was forest land-grassland-forest land; the ecological value index of the basin in the past 20 years showed an "N" shape trend, which reached the highest in 2008; The ecological value index of mountainous forest areas in the basin was higher than other areas and the ecological value was relatively stable; The key monitoring area of the basin should be located along the east-west section of the S212 provincial road and the area of Wangtan Town, after the implementation of the ecological resettlement of the basin, the relative ecological value index of the basin would increase slowly then quickly. The ecological value index of relocation increased from 0.015 to 0.084 and the ratio of whole basin increased 11.2%.[Conclusion] The reservoir had been in good ecological environment for nearly 20 years. The implementation of the project of returning farmland to forests and human activities were the main reasons affecting the changes in habitat quality of reservoirs in water source areas.

Abstract:[Objective] The effects of wood-source biochar on the soil aggregate structure were studied to find a suitable biochar addition and to provide a scientific basis for improving the soil structure and increasing crop yield for solar greenhouse soil in Yangling District, Shaanxi Province.[Methods] Five biochar treatments of 10, 30, 50, 70 and 90 t/hm², and a control treatment without any biochar, were set up. For all treatments, soil aggregate mean weight diameter, geometric mean diameter, damage rate and fractal dimension were calculated through the dry sieve method and the wet sieve method. And, crop yields under different biochar additions were also analyzed. Finally, an appropriate biochar addition was concluded both in considering soil aggregates and crop yields.[Results] The results showed that the mechanically stable dry aggregates significantly increased by 0.6~4.6 mg/kg and the dry microaggregates decreased by 4.0%~32.6% compared with that of control treatment. Further, after adding biochar, 3~2 mm, 2~1 mm and 1~0.5 mm water stable large aggregates increased by 25.3%~41.2%, 22.7%~74.2%, 9.1%~46.4% respectively; however 0.5~0.25 mm water stable large aggregates decreased by 2.1%~18.1%. Biochar could promote the formation of small size microaggregates, but have a non-significant effect on microaggregate stability and microaggregates. Additionally, biochar had a positive effect on the spinach fresh weight with an increase of 68.8%~214.9%.[Conclusion] Biochar can ameliorate the soil aggregate structure. Taking soil aggregates and crop fields into account, the 70 t/hm² biochar has the optimal effect in greenhouse.

Abstract:[Objective] After the Wenchuan earthquake, a large number of debris flow prevention engineering were constructed. The numerical simulation of the effects of debris flow prevention engineering in strong earthquake areas was analyzed to provide a scientific reference for the study and prevention of debris flow.[Methods] Using FLO-2D software, this paper simulates the movement process and accumulation range of debris flow under different rainfall frequencies, and analyzes and evaluates the effects of debris flow in the prevention and control project, combining rainfall data, digital elevation model(DEM) and rheological parameters of debris flow, taking the "8·13" debris flow in Huangyang gully, Longchi Town, Dujiangyan City in 2010 as a typical example.[Results] Under the condition of prevention engineering, when the rainfall frequency P=5%, the discharge volume of debris flow decreased by 11.39 times and the accumulation range decreased by 6.14 times; when the rainfall frequency P=2%, the discharge volume of debris flow decreased by 4.18 times and the accumulation range was reduced by 2.7 times. The prevention engineering achieved certain control effects, but solid matter still rushed out of the ditch at the two rainfall frequencies.[Conclusion] Compared with the natural conditions, the volume and size of the rushing out of the debris flow significantly reduced. The prevention engineering is conducive to the prevention and control of the debris flow in the gully. However, there will have the possibility of solid matter rushing out of the ditch, due to the small capacity of the reservoir. Therefore, hazard mitigation measures such as monitoring and early warning systems need to be strengthened in the further governance of debris flows.

Abstract:[Objective] The mechanism and effects of wind erosion prevention of farmland surface soil under different tillage patterns were compared and analyzed, so as to provide scientific basis for regional socio-economic and ecological environment construction.[Methods] Wind erosion tests were carried out on no-tillage, less tillage, autumn ploughing and subsoiling farmland surface soil in Minqin Oasis, Gansu Province, using indoor wind tunnel and related supporting equipment, wind erosion rate and sand transport rate were calculated, wind erosion movement law was studied, and wind erosion prevention of farmland surface soil was analyzed.[Results] The results showed that the effects of tillage measures on soil wind erosion rate were related to wind speed. When wind speed was small, the effects of different tillage patterns on wind speed were not significant, but when wind speed was greater than 14 m/s, the wind erosion rates of surface soils began to show significant differences in different tillage fields; the effects of less tillage, autumn tillage, deep loosening and other tillage patterns on wind erosion rate and sand transport rate of surface soils were significant. The wind erosion rate and sediment transport rate of farmland surface soil were the lowest under no-tillage tillage, and the higher the wind speed, the greater the gap. Wind speed, tillage and their interaction had a significant impact on the wind erosion rate and sediment transport rate of farmland surface soil.[Conclusion] No-tillage could effectively resist the wind erosion of the surface soil of farmland, greatly reduce the sand transport rate, showing excellent anti-wind erosion effect.

Abstract:[Objective] The practices and researches of soil and water loss comprehensive harness models in the red soil region of Southern China in the past decades were summarized and analyzed in order to provide references for appropriate application in soil and water conservation practice.[Methods] By reviewing related literatures and summarizing existed experimental results, taking Jiangxi Province as an example, according to the regional soil erosion problems, three aspects of corresponding harness patterns were proposed including soil erosion control technology, governance engineering practice and soil and water conservation policy.[Results] Patterns for those eroded lands which are difficult to be controlled or harmful to people in the red soil region, corresponding patterns were put forward from technical, practical and policy aspects. Technical patterns were summarized as following:the governance of "one control and two guarantees" on slope farmland; the "one high and two low" pattern on sloppy orchards land; the "three types" pattern on collapse erosion; the "two types" patterns eroded lands under forest; the "two types of strongly-eroded bare lands". Two practical patterns of comprehensive management of small watershed and small ecological-clean watershed were summarized. Policy-guided patterns were proposed, such as assistance for farmers, large-scale personal governance, reward replacing subsidy, boutique park construction.[Conclusion] Combining the long-term experiences and practices of soil erosion control in Jiangxi Province, the soil erosion control models and connotations in the new era were proposed. These models could provide references for the management of mountain-river-forest-farmland-lake-grass system.

Abstract:[Objective] The spatial and temporal evolution of vegetation on the Loess Plateau from 1990 to 2015 was studied, and the driving forces of vegetation change in this region were analyzed from the aspects of climate change and human activities in order to provide a theoretical basis for formulating policies related to ecological environmental protection and regional sustainable development.[Methods] Based on GIMMS NDVI and MODIS NDVI, long-term sequence NDVI datasets were established. During the period of 1990-2015, the linear trend analysis, multiple linear regression and improved human residuals were used to analyze the spatial and temporal variation of vegetation with NDVI and land use data in the Loess Plateau. The characteristics and their influencing factors were quantitatively analyzed.[Result] ① Between 1990 and 2015, the NDVI of the Loess Plateau showed an upward trend, and the trend of change was more clearly divided into two periods, of which the rate of NDVI increased faster after 2000. ② After 2000, the NDVI of the Loess Plateau increased rapidly, and the rising area reached 91.90% of the total area, of which the NDVI significantly increased area ratio was 65.78%. ③ The overall area of vegetation in the Loess Plateau increased, and it mainly came from the transfer of cultivated land. ④ The vegetation restoration area promoted by human activities accounted for 21.74% of the total area, mainly distributed in the eastern and northern parts of Inner Mongolia, southern area of Gansu and Ningxia Region, as well as the central areas of Shaanxi and Shanxi Province.[Conclusion] With the implementation of the policy of returning farmland to forest and grass land, the vegetation area in the Loess Plateau continued to increase, and the vegetation growth continued to improve. The main reason for the restoration of vegetation on the Loess Plateau was the combination of climate and humans, and the degree of human influence was relatively larger.

Abstract:[Objective] On the basis of calculating the decoupling elasticity of agricultural chemical input and agricultural economy, the influencing factors of agricultural chemical input and its spatio-temporal pattern evolution were further analyzed to provide bases for the protection of agricultural resources and environment in He'nan Province.[Methods] Based on the Tapio decoupling model, the decoupling relationship between agricultural chemical input and agricultural economy in He'nan Province was analyzed. LMDI decomposition model was used to decompose the influencing factors of agricultural chemical input, and K-means method was used to cluster the agricultural chemical efficiency in He'nan Province.[Results] From 1993 to 2016, the input of agricultural chemistry in He'nan rose firstly and declined lately. The inputs of agricultural film, pesticide and fertilizer showed their respective downward trends in 2012, 2014 and 2016. In the past 23 years, the trend of the relationship between agricultural chemical input and agricultural economic growth had changed from relative decoupling and expansive negative decoupling to relative decoupling, and then to a trend of absolute decoupling in He'nan Province. The cultivated land effect was the main driving force for the increase of agricultural chemical input, and the efficiency effect had a significant inhibitory effect on agricultural chemical input, and the scale effect was not obvious. From the perspective of spatial pattern, the growth of agricultural economy in the southeastern of He'nan was highly dependent on the agricultural chemical input, and the degree of agricultural chemistry participating in agricultural economic growth in the center and the northwest of He'nan Province was relatively low.[Conclusion] On the whole, agricultural chemical input and economic development of He'nan Province showed a decoupling state, but there were still large spatial differences within the region. Differential agricultural chemical control policies should be adopted in the future.

Abstract:[Objective] The changes of nitrogen and phosphorus and algae in the water under "rice-duck-shrimp ecological planting and breeding model were studied in order to provide a scientific reference for controlling agricultural non-point source pollution caused by nitrogen and phosphorus in the drainage of rice fields and improving the ecological environment of rice fields.[Methods] The differences and advantages of different planting modes were analyzed by comparing the ecological planting and breeding model of rice-duck-shrimp and the conventional planting model. The study focused on the impact of the internal synergy of rice-duck-shrimp on the changes of nitrogen, phosphorus and algae in water.[Results] ① The contents of total nitrogen(TN) and total phosphorus(TP) in rice-duck-shrimp ecological paddy field reduced by 32.43% and 19.35%, respectively. The removal rates of total TN and total TP in initial irrigation water were 38.7% and 26.9%, respectively. ② The changes of nitrogen and phosphorus forms were altered by the ecological planting and breeding mode of rice-duck-shrimp. During the whole growth period of rice, the proportion of soluble phosphorus(DTP) and granular phosphorus(PP) was more stable. However, the proportion of organic nitrogen(ON) in paddy water significantly increased in the later period of rice. ③ The rice-duck-shrimp ecological planting breeding model could improve the community structure of algae in water. The algae biodiversity index in paddy field drainage increased to 2.34. ④ Compared with conventional cultivation, the effective panicles, grains per spikee and seed setting rate of rice in rice-duck-shrimp ecological planting breeding model increased by 4.83%, 5.28% and 2.84%, respectively. Moreover, the protein content of rice increased by 8.15%, which significantly improved the economic benefits.[Conclusion] Compared with conventional cultivation, rice-duck-shrimp ecological planting and breeding model could not only effectively reduce the content of N and P in rice field water, increase the stability of water, but also improve the effective panicles, grains per spike and seed setting rate of rice, which increases economic benefits and does not bring the risk of heavy metal pollution. Therefore, it was worth popularizing as a farming technology.

Abstract:[Objective] Based on the simulation analysis of rainfall-runoff process and non-point source pollution load in each basin, the impacts of ecological construction in small watershed on the hydrological process and pollution control effect of Miyun Reservoir watershed were eraluated in order to provide scientific basis for water source protection, integrated restoration of mountain, water, forest, field and lake in watershed and ecological environment construction.[Methods] Taking the Sheyuchuan small watershed upstream of Miyun Reservoir, an important drinking water source in Beijing, as the research object, the model of combining EcoHAT-LCM model with traditional large-scale non-point source pollution model were used to simulate and analyze the ecological construction effect of the small watershed.[Results] With the increase of rainfall, the proportion of adsorbed N and P load to the total pollution load increased gradually, while that of dissolved N and P load to the total pollution load decreased gradually. When the residential areas in small watersheds had small town-level garbage disposal rate and garbage access rate, the pollution load of N and P in rural life could be reduced by 28%, and the existing fertilizer application in economic forests could be reduced by 43.9% and 48.9% in agricultural production activities.[Conclusion] The influence of different frequency rainstorm on adsorbed N, P load is greater than that on dissolved N, P load in the study area. The ecological restoration measures had a significant effect on the reduction of pollution load of non-point source N and P.

Abstract:[Objective] The conception of production-living-ecological place was used to design the soil and water conservation demonstration park(SWCDP), in order to improve the demonstration effect in ecological construction, science popularization and policy propaganda of soil and water conservation.[Methods] The pattern of production-living-ecological place and requirements for soil and water conservation measures of the Baoshan SWCDP in Pengzhou City, Sichuan Province were analyzed, based on synthesizing remote sensing images and field investigation data.[Results] ① The Baoshan SWCDP was divided into three zones including soil conservation and river bank protection for human settlement environment maintenance in valley living space, soil erosion control zone in hilly production space,and soil and water conservation for ecological restoration zone in alpine ecological space. ② It was necessary to implement protection measures such as river dredging, bank protection, river ecological corridor construction, and road and courtyard soil and water conservation in living space. For production space, it needed to adopt comprehensive soil and water conservation measures including conversion of sloping farmland to terrace, construction of irrigation and drainage and roadfacilities. The measures of debris flow control and closing land for afforestation should be implemented in ecological space. ③ Establishment of soil and water loss monitoring facilities, soil and water conservation technology exhibition hall, identification board of soil and water conservation facilities and functions based on the scenic spot of Taiyangwan, it could benefit to carry out in-depth propaganda and scientific popularization of soil and water conservation to public.[Conclusion] As a transition area from Chengdu Plain to Minshan Mountain, the Baoshan SWCDP in Longmen mountain area had an obvious pattern of production-living-ecological place and diverse needing of soil and water conservation measures. It was systematic and comprehensive to design the general layout and functional zone of Baoshan SWCDP using the new concept of production-living-ecological place. It fully embodied the principle of suiting measures to local conditions for soil and water conservation, and could improve the effects of comprehensive demonstration and science popularization.

Abstract:[Objective] The impacts of land use/cover change(LUCC) on the regional ecological environment in agro-pastoral transitional zone in Northern China were studied in order to provide a theoretical reference for future land use in similar areas.[Methods] Based on the changing survey information and land use data of Duolun County, Inner Mongolia Autonomous Region in 2004, 2009 and 2014, the spatio-temporal data from 2004 to 2014 was obtained. And consulting the research results of Costanza and Gao et al, the ecosystem service values, ecological environment quality index and the contribution proportions of land use/cover types were selected, to build the assessment system between LUCC and ecological environment qualty.[Results] ① The land use/cover types had obviously changed in 2004-2014. ② The total value of ecosystem services kept improving and mainly came from woodland. While the reduction of ecological service values of grassland, farmland, water area and unused land weakened the increasing trend in some extent, the change rules of ecosystem service values were similar to area changes respectively. ③ From the point of ecological environment quality index changes, the ecological environment quality of this study area improved. But from the change details, this change had two-way driving mechanism. Grassland transferred to farmland and construction land was the dominant factor of degradation of the ecological environment, while the unused land transferred to grassland and woodland promoted the improvement of the ecological environment quality.[Conclusion] In the process of ecological civilization construction, it should attach great importance to the impact of land use change on regional ecological environment in ecologically fragile areas, and guide the sustainable and high-quality development of regional population, economy, resources and environment by improving the efficiency of land use, strengthening the construction of "mountain, paddy field, forest, lake and grass" life community and building a reasonable land and space planning system.

Abstract:[Objective] The spatial and temporal evolution characteristics of land use in Horqin sandy land were studied in order to provide basic information for appropriate decision-making.[Methods] Based on the gravity center migration model of land use, the patterns and characteristics of spatial-temporal dynamics induced land use were analyzed with Landsat images from 1980 to 2016.[Results] The gravity center of vegetation migrated to the northwest at a rate of 64.6 m/a, and water body migrated to the southeast at a rate of 389.3 m/a. The gravity centers of construction land and cultivated land both migrated to the northeast at rates of 53.6 and 148.3 m/a, respectively. The gravity center of sandy land migrated to the southwest at a rate of 379.5 m/a.[Conclusion] There were great differences in the migration rate of gravity center among different land use types in different periods. The overall migration rate of construction land was the smallest, and water body and sand land were relatively large. This phenomenon was mainly related to the fragile ecological environment of Horqin sandy land, resulting in the sustained reduction of water resources and the rebound of sandy land at any time.

Abstract:[Objective] The ecological vulnerability and spatial variation characteristics of the Wujiang River basin in Guizhou Province were studied to provide a scientific reference for the ecological environment construction and protection in the area.[Methods] By constructing the evaluation index system, the AHP was used to weight the ecological vulnerability factors of the basin, and GIS was used to comprehensively evaluate the ecological vulnerability of the basin.[Results] ① The three classifications of quantile, equal interval and natural discontinuity had little effect on the classification of ecological vulnerability, but there were significant differences in area ratio, and the proportions of extremely fragile and potentially vulnerable watershed were the smallest. ② The ecological fragility of the basin is mainly fragile and moderately fragile, the areas of the two fragilities accounting for more than 50%. ③ Human activities have a significant impact on the ecological vulnerability of the basin. The surrounding areas of large and medium-sized cities such as Guiyang and Zunyi City are mostly and extremely vulnerable. ④ The spatial distribution of the generally fragile areas in the basin is relatively scattered, which is not conducive to the ecological environment protection of the basin.[Conclusion] The ecological vulnerability level of the basin is gradually reduced from the upstream to the downstream, and the spatial distribution characteristics of vulnerability are obvious. The protection of the ecologically fragile areas of the basin in terms of the local conditions has a great effect on reducing the ecological vulnerability of the basin.

Abstract:[Objective] The ecological system service value of wetlands in Loess Plateau was evaluated scienti-fically in order to preserve the wetland ecological service, and to formulate a complete ecological conservation and compensation policy in Loess Plateau.[Methods] Based on fundamental data and other relevant data in Qianhu National Wetland Park, Shaanxi Province, direct and indirect usage values, including air regulation, water storage and retention and others 7 items of ecosystem service values were divided into estimated by methods of market-price, shadow-price and carbon tax, and so on.[Results] Among all the ecological system service values, air regulation service had the highest value which accounted for 87.5% of total ecological system service value; followed by cultural use, which accounted for 5.73% of total service value. The water purification service had the lowest value, which only counted for 0.09%. The system service value went up about 7.90×10⁵ yuan per hectare, which was smaller than that of Hechuan Wetland, another wetland located in Shaanxi Province.[Conclusion] The total value of the ecosystem service functions were about 3.30×10⁸ yuan. The indirect use value of ecosystem service accounted for 90.5%, which was markedly higher than that of the direct use value (9.5%).

Abstract:[Objective] Bedding rock landslide is one of the most developed disasters in daba mountain areas. A prediction evaluation model is constructed to provide scientific support for disaster prevention and pre-disaster work in this area, by studying the contribution rate and vulnerability of its development factors.[Methods] This paper selects the sample of 21 bedrock bedding landslides in the study area, and the basic data of nine influencing factors such as elevation, slope and slope structure were extracted by GIS technology. The samples were calculated by quantitative theoretical calculation methods to determine the category score of the factors, and then evaluates the whole range.[Results] The factors affecting the high contribution rate of landslide are:slope around 10°~20°, beding slope structure, rock mass structure of sandy hard rock with soft rock, confluence area, water erosion; The susceptibility prediction method established by quantitative theory Ⅱ can accurately divide the regional susceptibility.[Conclusion] The landslide susceptibility prediction method combined with GIS and quantitative theory Ⅱ is suitable for the study of landslide susceptibility and risk in this area.

Abstract:[Objective] The vegetation in the tailing ponds of Qinling mining areas was investigated in order to provide theoretical basis for vegetation restoration and reconstruction in mining areas.[Methods] Four sites of goal tailing ponds after closures of 2, 3, 6 and 14 years in Shangzhou District, Shaanxi Province were taken as the research objects. The top and slope of the tailing tailing ponds sites were investigated, mainly referring to 5 indexes of floral name, height, density, coverage, dominance.[Results] ① The relative height of tailing ponds after 6 years closure was the highest, followed by the ones after 14, 3 and 2 years closures. ② The relative density was the highest after 14 years closure, followed by that after 6, 3 and 2 years closures. ③ The highest vegetation coverage was observed in 6 years closed mine, followed by the ones of 14, 3 and 2 years closed mines. ④ The 14 years closed mine tailing pond had the highest vegetation coverage, followed by the 6 years, 3 years and 2 years closed mine tailing ponds. ⑤ Plants of the Compositae and Gramineae were the majority in the tailing ponds. The 6 years closed mine had the highest dominance, followed by ones of 14, 3 and 2 years closed mines.[Conclusion] The restoration of natural vegetation in the gold tailings reservoir area is closely related to the closure years. Artificial soil covering can significantly increase the diversity of natural restoration vegetation types.

Abstract:[Objective] The coordination degree of eco-economic system in the Central China were evaluated in order to provide theoretical advice for the eco-economic system governance in the region.[Methods] Based on the GDP data of the six central provinces in 1992, 2000, 2008 and 2016 and the land use data of Landsat TM remote sensing image, the ecosystem service value(ESV) and eco-economic system coordination(EEH) was caculated, and its eco-economic system coordination degree and spatial-temporal evolution characteristics were evaluated.[Results] ①Since 1992, the GDP of the Central China had shown a rapid growth pattern, but the growth rate had obvious spatial-temporal differences. Anhui and Jiangxi Province were faster than other provinces, Hu'nan Province had the slowest growth; ② The Central China ecosystem service value(ESV) fluctuated, it showed a benign development trend. The spatial distribution characteristics were higher in the south than in the north and higher in the west than in the east. ③ The coordination degree of the eco-economic system(EEH) in the central region was more obvious in 1992-2016, and the EEH in Anhui and Hubei Province showed an improvement trend. The EEH in He'nan Province was the highest, and the improvement in other provinces was not obvious or had a downward trend.[Conclusion] Due to the differences in natural conditions and social economy in various regions, the eco-economic system coordination degree(EEH) had certain differences, and the level of sustainable development also showed a certain spatial differentiation.

Abstract:[Objective] The content changes, cause and pollution risk of heavy metals in cultivated land around phosphogypsum yard were studied in order to provide scientific basis for sustainable development of phosphate industry and remidiation of water or soil heavy metal pollution.[Methods] Researches and analyses were carried out by field investigation and sampling of the phosphogypsum yard in Central Guizhou Province.[Results] The the contents of Cd, Hg and As in the drainage of phosphogypsum yard, erosion gully water and shoal water were exceeded the water quality limit of farmland irrigation water quality, especially Cd. In the range of 50~300 m around the phosphogypsum yard, the content of Cd in corn field, vegetable field and paddy soil were respectively exceeded 4.87~9.43 times, 8.83~19.13 times and 3.83~13.42 times of the soil pollution risk screening value of agricultural land. The dry soil around the yard was mainly the pollution risk of Cd, As and Zn, while the paddy soil was mainly the pollution risk of Cd, As, Hg and Zn. The content of Cd in most vegetable soils and paddy soils exceeds the control value of soil pollution risk in agricultural land.[Conclusion] The erosion and leaching of natural rainfall on the phosphogypsum yard was the main reason for the migration of heavy metals. In the direction of surface water flow, the risk of heavy metal pollution in cultivated land gradually decreases with the increase of the distance of the yard. The improvement of irrigation and drainage facilities and the adjustment of planting structure were effective ways to reduce heavy metal pollution in cultivated land around the phosphogypsum yard.

Abstract:[Objective] This paper conducted a quantitative study on the water footprint and irrigation efficiency of green water and blue water in urban agriculture in guiyang city, so as to provide a basis for scientific quantitative evaluation of urban agricultural water use and management monitoring.[Methods] Using field survey data, meteorological data of Guiyang City and agricultural statistical data, based on crop water demand, water footprint method to evaluate agricultural water resources.[Results] ① The extreme value of crop water footprint depends on the extreme value of crop yield per unit area of the sample plot. The green water footprint and blue water footprint were 741.60, 153.48, 424.44 and 87.84 m³/t. ② The green water consumption of different crops in urban agriculture was higher than the blue water consumption. The proportion of green water and blue water ranged from 53.81%(cowpea) to 63.60%(tomato). ③ The three irrigation efficiencies of urban agriculture are 27.23%, 69.45% and 80.32%, respectively. ④ In 2017, the urban agricultural blue water irrigation demand is between 4.81×10⁵ m³ (complete drip irrigation) and 6.93×10⁵ m³(complete ditch irrigation).[Conclusion] In 2017, the total water demand for urban agriculture in Guiyang City was 1.29×10⁶ m³, of which 8.84×10⁵ m³ was green water and 4.02×10⁵ m³ was blue water. The irrigation method has great room to improve the urban agricultural water use in Guiyang City, and the contribution rate of drip irrigation method to the urban agricultural water resource management in Guiyang City is up to 53.09%.

Abstract:[Objective] Soil erosion characteristics and impact factors in north and south slopes of the Eastern Tianshan Mountains in Xinjiang Wei Autonomous Region were investigated and studied in order to provide scientific basis for the prevention and control of soil erosion.[Methods] In the north and south solpes of the Eastern Tianshan Mountain, 14 survey units were selected to investigate the types and characteristics of soil erosion, land use types and vegetation growth status from June 25 to 30, 2019.[Results] Soil erosion mainly occurred in grassland and construction land. Grassland degradation was serious and grazing led to scaly erosion and animal erosion. And, some areas were exposed to denudation, sapping and sheep path erosion. There were less land protection measures in construction, and gully erosion was the primary form.[Conclusion] Over grazing had led to slowing recovery of grassland ecosystems, and construction had destroyed the original ecosystem, causing serious artificial acceleration of erosion and seriously threatening the ecological security of the Tianshan region. It was urgent to carry out soil erosion monitoring and research on the basic data, strengthen the work of soil and water conservation, establish a reasonable grazing system, speed up the restoration of the ecosystem, reduce soil and water loss, and ensure the ecological safety and healthy development of Tianshan Mountains.

Abstract:[Objective] The characteristics of soil erosion on sloping farmlands in the Mollisol region of Northeast China were analyzed in order to provide important scientific basis for the research, and the effective prevention and control of compound soil erosion.[Methods] Based on field investigation, theoretical researches and literature review, this paper outlined current status of compound soil erosion and analyzed characteristics of soil erosion on sloping farmlands in the Mollisol region of Northeast China.[Results] The characteristics of soil erosion on sloping farmlands in the Mollisol region of Northeast China included seasonal alternation and spatial overlapping of compound soil erosion induced by multi-forces, severe gully erosion in farmlands, strong performance of inflow erosion, and raindrop impact and seepage flow were key driving forces for hillslope soil erosion. The current research of compound soil erosion covered effects of freeze-thaw action on wind and water erosion, compound soil erosion by wind and water agents, and compound erosion caused by multi-forces in the Mollisol region of Northeast China.[Conclusion] The key fields for studying compound erosion caused by multi-forces were as follows:① processes and mechanisms of hillslope compound erosion caused by multi-forces; ② mechanism of freeze-thaw impacts on soil anti-erosivity; ③ quantifying contribution of freeze-thaw, snow melting, rainfall and inflow to hillslope soil erosion and gully erosion; ④ identifying watershed sediment source under multi-forces actions; ⑤ developing compound soil erosion prediction model; ⑥ assessing effectiveness of conservation measures for controlling compound soil erosion; ⑦ prevention zonalization of compound soil erosion in the Mollisol region of Northeast China.