Abstract:[Objective] To systematically categorize， summarize， and analyze the current understanding of synergistic interactions among rocks，soil，and plants，discuss the mechanisms of plants' adaptation to lithified soil environments，in order to provide theoretical support and scientific evidence for the growth of vegetation and ecological environment restoration in stony habitats. [Methods] From different dimensions such as the content and burial depth of internal rock fragments， external vegetation types， and rainfall and climatic conditions， a comprehensive analysis of the effects of rocky soil on plant growth was conducted to reveal the adaptive strategies of plants at the morphological，physiological，and molecular levels in the rocky habitats. [Results] The regulatory effect of stony soil on plant growth is closely related to factors such as rock shape，content，burial depth，climatic conditions，and plant types. The main limiting factors for plants in stony soil are soil moisture and nutrient scarcity. Under such circumstances，plants will better cope with environmental stress by regulating their own growth traits and physiological metabolism. [Conclusion] The following three aspects can be expanded and deepened in the future. 1） The synergistic effects of different types of microorganisms in rocky soil on plant growth and development，as well as the genetic adaptation mechanism of plants. 2）Seeking the optimal combination of rock fragment parameters suitable for plant growth in rocky soil environments. 3）Future research should focus on optimizing and screening suitable plants for specific regions，selecting plant varieties with strong stress resistance to promote stable plant colonization in the area，and gradually improving and enhancing the quality of the ecological environment.

Abstract:[Objective] To investigate the characteristics of rill erosion on slopes under different slope gradients and rainfall-runoff conditions. [Methods] Continuous simulated rainfall and upper slope inflow tests were conducted to study the erosion processes on slopes with two slope gradients（5° and 10°）and across three rainfall-runoff stages （rainfall，inflow，and rainfall＋inflow）. [Results] The volumes of slope runoff and erosion increased with slope gradient. Under rainfall conditions at a 5° slope，the runoff and erosion volumes were 1.06 and 2.23 times of those under inflow conditions，respectively，while at a 10° slope，the runoff and erosion volumes were 1.26 and 3.34 times of those under inflow conditions. The runoff rate initially increased over time and then tended to stabilize. The initial runoff production time occurred earlier with increasing rainfall frequency and slope gradient，with both the stable runoff rate and sediment yield rate increasing correspondingly. Under the same slope gradient，the contribution rates of slope runoff and erosion under continuous rainfall conditions decreased with each additional rainfall event. Under continuous inflow conditions，the contribution rate of slope runoff was the highest during the first event，reaching 56.40%，while the contribution rate of slope erosion was the highest during the third event， being 87.50%. Correlation analysis revealed that slope runoff and erosion were highly significantly correlated with the rainfall inflow treatments and the interaction between slope gradient and rainfall inflow treatments（p<0.001）. Variance analysis indicated that the effects of rainfall inflow treatments on slope runoff and erosion were highly significant（p<0.001），while the effects of slope gradient were moderately significant（p<0.01）. Rill erosion accounted for 37.69%—85.45% and 53.99%—90.65% of the total slope erosion at the two slope gradients， respectively，with rill erosion increasing as the gradient increased. [Conclusion] The findings contribute to a deeper understanding of the mechanisms of rill erosion and hold significant implications for soil and water conservation efforts in the black soil region of Northeast China.

Abstract:[Objective] By studying the influence of the morphology and spatial distribution of exposed bedrocks on soil erosion on karst slopes，it is helpful to deepen the understanding of erosion laws under natural rainfall conditions on karst slopes，and to provide a reference for rocky desertification control in karst areas. [Methods] Through the monitoring of natural rainfall，the effects of natural rainfall，the morphology and spatial distribution of outcropping bedrock on the sediment production of karst slopes were studied by taking different rock-soil covered slopes as the research objects. [Results] 1）The change in the morphology of exposed bedrock could significantly affect surface runoff，and such effect was rain-intensity dependent. 2）The morphology of exposed bedrock was one of the key factors in the dynamic changes of soil flow，and the spatial distribution of bedrock significantly affected the formation of soil flow under different rainfall intensities. Among them，the aggregation distribution（R-type）was the most conducive to the generation of soil flow. 3）The change of bedrock morphology mainly affected the underground runoff under the conditions of light rain and moderate rain，while in large-scale rainfall events（such as rainstorm and heavy rainstorm），the spatial distribution pattern of bedrock was closely related to the formation of underground runoff. 4）The morphology and spatial distribution of exposed bedrock played an important role in soil erosion and sediment transport during extreme rainfall events. [Conclusion] The morphological changes of exposed bedrock significantly affect the trends of surface runoff and soil flow，and such effects vary with rainfall intensity. In the future，soil erosion control measures should be taken according to different rainfall types.

Abstract:[Objective] To explore the variation patterns and cross-sectional distribution characteristics of rill erosion and its morphological features. [Methods] Indoor artificially simulated rainfall experiments and 3D laser scanning were conducted to analyze the distribution of runoff，sediment yield and rill morphological characteristics of rill erosion under different rainfall and slope conditions. [Results] 1）When the rainfall intensity increased，the runoff and sediment yield increased significantly. When the rainfall intensity was 90 mm/h，the contribution rate of rill erosion to total erosion could reach more than 90%. 2）Rill width，depth，width-to-depth ratio and rill splitting degree were significantly affected by rainfall intensity，and all showed varying degrees of increase. Rill splitting degree and the maximum depth of rill showed a significant positive correlation with the amount of rill erosion. 3）Rill cross section varied greatly along the slope direction，the collapse of the gully wall was obvious. When the rainfall intensity was 60 mm/h，the rill cross section was mostly distributed in a "narrow and shallow" shape，When the rainfall intensity was 90 mm/h，the head and bottom of the rill were "narrow and shallow"，the middle of the rill was "wide and deep" in general. The rill erosion in the middle was more severe. 4）When the rainfall intensity was 60 and 90 mm/h，the overall value range of rill cross-sectional index were 0.46—0.79 and 0.41—0.85，respectively. When the rainfall intensity was 60 mm/h，the volatility of rill cross-sectional index increased with the increase of slope gradient，indicating that spatial differentiation of rill cross section was more obvious，and variation of the rill cross section tended to be irregular. [Conclusion] The research results can provide some theoretical support for rill erosion prevention and control.

Abstract:[Objective] To explore the effects of roots on soil consolidation and erosion reduction under different planting densities. [Methods] Typical herbaceous plants， including ryegrass （Lolium perenne） and alfalfa （Medicago sativa）on the Loess Plateau were selected as the research objects. By setting three planting densities， i. e. 100，300 and 500 plants/m²，the effects of plant root growth on soil resistance to erosion were studied experimentally. [Results] During the observation period，the root characteristics showed a trend of rapid increase at first and then slow decrease，with those of ryegrass and alfalfa being the best in medium and high planting-density plots，respectively. Driven by root growth，soil organic matter content showed an increasing trend，with that of ryegrass and alfalfa increasing the most in medium and high planting-density plots，which increased by 2.44 g/kg and 1.84 g/kg，respectively. Under the combined influence of changes in root and soil characteristics，rill erodibility index decreased rapidly at first and then showed a fluctuating change during the observation period，while soil critical shear stress did not show a stable trend. Ryegrass roots had the best erosion reduction effect in the medium planting-density plot，where rill erodibility index decreased by 18.86 s/m. Alfalfa roots had the better erosion reduction effect in the medium and high planting-density plots，where rill erodibility index decreased by 13.42 s/m and 10.82 s/m， respectively. [Conclusion] Considering the effect of planting density on roots and soil characteristics，the medium density（300 plants/m²）and high density（500 plants/m²）planting patterns are suitable for soil erosion control by growing ryegrass and alfalfa，respectively.

Abstract:[Objective] The implementation of soil and water conservation measures has led to a notable reduction in the loss of soil carbon pools，while simultaneously facilitating effective control of soil erosion. However，there is a paucity of systematic understanding of the processes of carbon loss，flux characteristics and the factors that influence them under different soil and water conservation measures. [Methods] In this study，a comparative analysis of the characteristics and influencing factors associated with the loss of dissolved organic carbon（DOC） and inorganic carbon（DIC）from loess slopes under different soil and water conservation measures was conducted. These measures included terraces，grasslands，upper terraces and lower grasslands，and the upper terraces and lower bare soil. To this end，a simulated rainfall test in the field was employed to quantify the benefits of the above-mentioned soil and water conservation measures in reducing the loss of dissolved carbon from the slopes. [Results] The dissolved carbon concentration on the slope surface under each soil and water conservation measure remained relatively constant throughout the rainfall process. However，the flux of dissolved carbon loss was significantly lower than that observed on bare ground（p<0.05）. Furthermore，the loss of dissolved inorganic carbon contributed to 79.5%—83.1% of the total carbon loss. The retention benefits of grassland，the upper terraces and lower grasslands，the upper terraces and lower bare soil measures for dissolved carbon on slopes were 76.9%，56.3%，47.6% and 18.0%，respectively. The volume of flow production on the slope surface was identified as the determining factor affecting the flux of dissolved carbon loss. Furthermore，the flux of carbon loss was found to be significantly positively correlated with the flow volume. [Conclusion] This study enhances our understanding of the mechanisms through which soil carbon loss is mitigated by diverse soil and water conservation measures. It offers a scientific foundation for evaluating the carbon sink benefits of soil and water conservation on the slopes of the Loess Plateau.

Abstract:[Objective] To explore the effects of different sand control measures on soil physicochemical properties and enzyme activity in sand blocking and stabilization zones，and their relationships，in order to provide technical support for measure selection and benefit evaluation. [Methods] Using mobile sand dunes and Haloxylon ammodendron （CK）as the control group，and ecological cushion sand barrier+Haloxylon ammodendron（ES），nylon mesh sand barrier+H. ammodendron（NS），woven bag sand barrier+H. ammodendron（WS），grass square grid sand barrier+H. ammodendron（GS），and clay sand barrier+H. ammodendron（CS）as the test groups，physical and chemical properties and enzyme activities of soil within 0~60 cm depth for six different sand control measures were analyzed. [Results] Compared with CK，there were significant changes in soil physicochemical properties and enzyme activities among the other five different sand control measures. 1）Within the depth range of 0~60 cm，there was no significant change in soil pH，but soil moisture content（SWC）increased with increasing soil depth. The mass fractions of soil organic carbon（SOC），total nitrogen（TN），total phosphorus（TP），and total potassium （TK）decreased with increasing soil depth. Compared with CK，the other five different sand control measures had a significant increase in soil nutrient content，with NS showing the most significant increase. 2）Under different desertification control measures，soil enzyme activities of NS measure were the highest，followed by that of GS，and that of CS were the lowest. Within the depth range of 0~60 cm，soil enzyme activities showed a decreasing trend. 3）There were significant correlations between soil physicochemical properties and soil enzyme activities. The contribution of soil physicochemical properties to soil enzyme activities varied under different desertification control measures，and soil enzyme activities were mainly influenced by TK，SOC，and SWC. [Conclusion] Five different sand control measures have varying degrees of promoting effects on soil physicochemical properties and enzyme activities，among which NS sand control measures have the best ecological benefits and long-term stability.

Abstract:[Objective] The effective mixing depth is an essential parameter for quantifying and predicting solute loss. It is of great significance to quantify the effective mixing depth of texture-differentiated soils and investigate the response of effective mixing depth to soil erosion，and solute loss in the modeling of agricultural non-point source pollution. [Methods] The topsoils of five texturally distinct dry croplands in the Danjiangkou Reservoir Region were selected as the research object. The bromine ion tracer method was employed to quantify the effective mixing depth and its dynamic changes in texturally distinct soils. Simulated rainfall tests were conducted according to different bromine application depths[0（soil surface），0.5，1，2 and 5 cm]to determine the process of soil erosion and solute loss and analyze their responses to the effective mixing depth. [Results] Under the experimental conditions established in this study，the effective mixing depths during rainfall exhibited a range of 0.32—0.72， 0.11—0.57， 0.44—2.41， 0.11—1.04， and 0.13—0.28 cm. The effective mixing depths were found to be significantly affected by the clay content and soil texture（F=39.27，p<0.001）. However，the effective mixing depths of different textured soils were significantly affected due to the differences in infiltration and flow production processes of different soil textures. Consequently，a significant linear relationship was not observed between the two. Furthermore，the effective mixing depth demonstrated a dynamic variation during the rainfall process，and exhibited a pronounced power function relationship with rainfall duration（R2 >0.80）. Furthermore，a notable distinction was observed in the soil erosion and sand production processes across varying effective mixing depths （F>12.068，p<0.001）. Regression analysis demonstrated that the mean effective mixing depth exhibited a significant linear correlation with cumulative soil runoff and cumulative bromine loss（R²>0.92），as well as a significant exponential function relationship with sand production rate，sediment concentration，and cumulative sand production（R²>0.94）. [Conclusion] The effective mixing depths of various textured soils exhibit notable disparities. A substantial linear or exponential correlation exists between the effective mixing depth，soil erosion， and solute loss indices. This correlation can be inverted through the runoff generation and sediment yield characteristics of the effective mixing depth，thereby enhancing the precision of the solute loss model.

Abstract:[Objective] Research on the effects of the duration of straw returning on rill erosion resistance can provide scientific evidence for rill erosion modeling and controlling in sloping farmland. [Methods] Taking straw returning durations of 0 years（CK），3—4 years（R1），5—6 years（R2），7—8 years（R3），9—10 years（R4）， 15 years（R5），and 20 years（R6）as the study subjects，soil samples were collected and analyzed. Partial least squares regression analysis was applied to identify the main controlling factors of soil erosion resistance under straw returning conditions. [Results] 1） With the increase of straw returning duration， rill erodibility（K_d） first decreased，then increased，and decreased again. The K_d values of R2，R3，R5，and R6 were significantly lower than that of CK[170.38 cm³/（N·s）]. With the increase in the duration of straw returning，soil critical shear stress （τ_c）showed a trend of first increasing and then decreasing，with the pattern of R1=R3>R2>CK>R4>R6> R5，although the differences among treatments were not significant. 2）Compared to CK，all straw returning treatments reduced soil bulk density（BD），the content of water-stable aggregates >0.25 mm（WG_0.25），and exchangeable sodium ions，while increasing total porosity and soil saturated moisture content（SWC），although the effects on soil properties varied across treatments. 3）Among all the main controlling factors of K_d，K_d decreased with the increases in exchangeable magnesium ions，soil organic matter，humic substances，fulvic acid （FA），humin，and exchangeable calcium ions，but increased with the increase in WG_0.25. Among all the main controlling factors of τ_c，τ_c was positively correlated with FA，dry-sieved aggregates >0.25 mm，and BD，and negatively correlated with soil moisture content and SWC. [Conclusion] Straw returning for 5—8 years or 15—20 years significantly reduced K_d，helped to improve soil erosion resistance and can effectively control rill erosion.

Abstract:[Objective] This study aimed to clarify the characteristics of soil nutrient accumulation and nitrogen and phosphorus loss for the greenhouse vegetable in Jiangxi Province，thereby providing scientific data for the accurate evaluation on pollution risk and promoting the healthy development of vegetable industry in this province. [Methods] Multipoint sampling was used for analysis cumulative amount of nutrients within the 0—100 cm depth soil layer in greenhouse vegetable throughout 11 cities and districts of this province，and in situ monitoring was used to analyze the characteristics of nitrogen and phosphorus loss. [Results] 1）The soil was severely acidified. The soil layers within 0—20 and 20—40 cm under surface showed pH values of 5.44 and 5.56，respectively. 2）The soil nutrient content in 0—20 cm soil layer was at the medium fertility level，and the soil nutrient increased with the extension of planting time when the planting years were less than 10 years，and began to decline when the planting years were 11— 20 years（except for available phosphorus）. 3）The runoff from greenhouse vegetable is mainly driven by rainfall and has the characteristics of high volume and low concentration；runoff occurs in the period from February to June accounts for more than 75% of the annual runoff amount and more than 60% of the annual nitrogen and phosphorus loss. [Conclusion] The 6—10 years might be a“turning point”for the cumulative contents of nutrients in greenhouse vegetable plots. Excessive use of nutrients after 6—10 years could not increase the storage capacity of the soil，but it might increase the risk of pollution caused by the accumulation of available nutrients. Due to the degenerated function of regulation，storage and purification of ditches and ponds，the generation of short-term，high-flow and low-concentration runoff water from greenhouse vegetable is difficult to be consumed in farmland ecosystem locally in at present. Therefore， the construction of greenhouse vegetable-single season rice composite farming model may be an effective means to solve the non-point source pollution of from greenhouse vegetable in red soil areas in southern China.

Abstract:[Objective] Conducting research on lake area changes on the Inner Mongolia Plateau is of great significance for deep understanding of regional water resource changes. [Methods] The Google Earth Engine （GEE）platform and Landsat image data were used to obtain annual lake area data on the Inner Mongolia Plateau from 1988 to 2021，and methods such as trend testing and hierarchical segmentation were used to analyze the spatiotemporal change characteristics of lakes and their influencing factors. [Results] 1）From 1988 to 2021，the area and number of lakes in Inner Mongolia showed a trend of first reduction and then recovery. On an inter-annual scale，the lake area was the largest in 2021，reaching 4 363.63 km²，and the smallest in 2002，only 1 915.61 km². In terms of the number of lakes，the number of lakes larger than 1 km² increased from 71 in 2002 to 458 in 2021. 2）Between 2012 and 2021，the area of lakes on the Inner Mongolia Plateau gradually recovered，and mainly concentrated in Alxa League，Xing’an League and Hulunbuir City. 3）The changes in lake area on the Inner Mongolia Plateau were mainly affected by climate change and human activities. From 1988 to 2012，human activities were the main driving force of lake area changes，and lake area was significantly positively correlated with precipitation. There was a significant negative correlation between lake area and irrigation，grazing and coal production. After 2012，climate factors were the main factors affecting changes in lake area. [Conclusion] The results elucidate the relationship between lake area changes，climate and human activities on the Inner Mongolia Plateau，and provide a scientific basis for ecological protection and restoration of plateau lakes.

Abstract:[Objective] To explore the changes of soil physical and chemical properties and enzyme activities of four vegetation types in desert saline-alkali lands in the Hexi Corridor and their influencing factors，and to provide a theoretical basis for soil nutrient cycling and regulation mechanism in desert saline-alkali lands. [Methods] Taking the desert saline-alkali soil in the Hexi Corridor as the research object，four typical vegetation types，including Lycium ruthenicum Murr. single community（HH），L. ruthenicum and Phragmites australis community（HL）， L. ruthenicum and Alhagi camelorum Fisch. community（HT），L. ruthenicum and Tamarix chinensis Lour. community（HC），were selected. Three replicate plots were set up for each vegetation type. Through the combination of field investigation and indoor analysis，soil physical and chemical properties（including organic carbon，total nitrogen，total phosphorus）and enzyme activities（including urease，alkaline phosphatase，nitrate reductase，nitrite reductase）of the four vegetation types were measured. Variance analysis and redundancy analysis were used to evaluate the differences in soil physical and chemical properties and enzyme activities，and the influencing factors were analyzed. [Results] In the soil of the four different vegetation types in the Hexi Corridor，organic carbon content increased with the increase of soil depth，being the highest in HC and the lowest in HH，and the difference was significant（p<0.05）. Total nitrogen content decreased with the increase of soil depth，being the highest in HH and the lowest in HC，and the difference was significant（p<0.05）. There was no significant change in total phosphorus（p>0.05）. The activities of urease，alkaline phosphatase，nitrate reductase and nitrite reductase decreased with the increase of soil depth，showing the phenomenon of surface aggregation. The activities of alkaline phosphatase，nitrate reductase and nitrite reductase were significantly different among different vegetation types（p<0.05），being the highest in HL，HH and HT，and the lowest in HT，HC and HH， respectively. Total nitrogen content was significantly positively correlated with urease and nitrate reductase activities（p<0.05）. In the 20—40 cm soil layer，organic carbon content was significantly negatively correlated with urease and nitrate reductase activities（p<0.05）. [Conclusion] The changes of different vegetation types and soil layers cause significant changes in soil physical and chemical properties，and then regulate the changes and distribution of soil enzyme activities. Soil total nitrogen and organic carbon contents are the key factors affecting soil enzyme activities，and can better explain the distribution and change characteristics of soil enzyme activities.

Abstract:[Objective] The sources and quantitative characteristics of soil moisture in the root zone of crops in the Huaibei Plain from 1990 to 2022 were explored to provide scientific guidance for crop irrigation management and water resource utilization. [Methods] The contribution of precipitation and groundwater to soil water in the root zone was calculated by Pearson correlation analysis and multiple regression，and soil water quantitative simulation was performed using multiple linear regression and long short-term memory network（LSTM）model. [Results] 1）For summer corn，in the 0—10 cm soil layer，except for the 55% contribution of precipitation during the seedlingjointing period，the contribution of groundwater in other stages could reach 61%—68%；in the soil layer below 10 cm，the soil water in the root zone mainly came from soil water in the adjacent upper layer，accounting for more than 74%. In the later stage，the root system gradually growed to 100 cm，especially in the 40—80 cm soil layer， the contribution of groundwater to soil water increased significantly，accounting for 9%—22%. 2）For winter wheat，in the 0—10 cm soil layer，except for the sowing-seedling period and the greening-jointing period，the contribution of groundwater in other stages could reach 54%—73%；in the soil layer below 10 cm，the soil water in the root zone mainly came from soil water in the adjacent upper layer，accounting for more than 63%. However，in the 40—80 cm soil layer，the contribution of groundwater and precipitation increased. 3）The LSTM model was more stable and accurate than multiple linear regression in quantitatively simulating soil water. The model evaluation index could reach R²>0.6 and MSE<10，which could better reflect the dynamic changes of soil moisture. The application of the above simulation results at other stations in the Huaibei Plain further verified the feasibility of the model. [Conclusion] The main source of soil water in the 0—10 cm layer for summer corn is groundwater，and the main source of soil water in the 0—10 cm layer for winter wheat is precipitation；the main source of soil water below 10 cm is soil water in the adjacent upper layer（including precipitation，irrigation water， etc.）. Performing quantitative simulation based on the sources of soil water in the root zone at different growth stages，and dynamically adjusting the irrigation plan through the changing trend of soil moisture in the root zone of the crop is helpful to optimize irrigation management and improve water resource utilization efficiency.

Abstract:[Objective] In order to investigate the effects of forest type conversion on the hydrophysical characteristics of forest soils. [Methods] The effects of forest type conversion on soil porosity，permeability，and matric potential，using subtropical natural evergreen broad-leaved forests and the secondary forests were compared，Castanopsis carlesii artificial forests，and Cunninghamia lanceolata artificial forests derived from them as research subjects. [Results] 1）After forest type conversion，total soil porosity in the lower soil layer of secondary forests significantly increased by 5.43% compared to natural forests. Soil matric potential also significantly increased in C. lanceolata artificial forests during the dry season by 5.01 kPa compared to natural forests. However，the variation of soil permeability in different forest types was not significant. 2）In the 0~40 cm soil layer of the four forest types，soil particles were mainly dominated by sand particles， but only clay particles and silt particles showed a significant correlation with total soil porosity，and soil particle composition was not the controlling factor for soil water-holding indicators under forest type conversion. 3）The main controlling factors for soil water-holding indicators were soil bulk density and soil moisture，with significant correlations between soil bulk density and each water-holding indicator，while forest conversion leaded to changes in soil bulk density and soil moisture，thereby causing changes in soil water-holding performance. [Conclusion] Forest type conversion has a significant impact on the hydrophysical parameters of subtropical region soils，with the conversion from natural forests to secondary forests being beneficial for water conservation or soil retention，and conversion to C. lanceolata artificial forests requiring soil amelioration measures to optimize their water retention and permeability. The results can provide a theoretical basis and data support for sustainable management of subtropical forests and water conservation.

Abstract:[Objective] To thoroughly investigate the effects of extreme climate events on the net primary productivity（NPP）of vegetation in the Qinba Mountain area. [Methods] Using the Qinba Mountain area as an example area，161 meteorological station observations from 1960 to 2023 and MOD17A3 dataset from 2001 to 2020 were used，and fitted regression，ridge regression and other analytical methods were applied to study the spatial and temporal evolution of the two and to quantify the contribution of extreme climate indices to the trend of NPP change. [Results] 1）the overall development of NPP in the study area was favourable，with an average annual growth rate of 5.02 g/（m²·a）（calculated by C）. 2）Extreme warm events significantly increased and extreme cold events significantly decreased in the Qinba Mountain area from 1960 to 2023，whereas the changes in extreme precipitation events were not obvious. 3）Changes in the CSDI，ID，TN10p，CDD，R10，R^{2p>0 and TR had a positive impact on the NPP trends，with the greatest contribution from the TN10p；changes in the Rx5day negatively affected the NPP trends. [Conclusion] The study can provide data or theoretical support for the conservation of terrestrial ecosystems in the Qinba Mountain area under the background of climate warming and for coping with extreme climate events.}

Abstract:[Objective] The strong dissolvability of carbonate rock leads to the spatial distribution of karst soil and bedrock，and the outcroppings of bedrock are common，but the mechanism of their influence on hydrological processes is still unclear. In order to investigate the influence of outcropped bedrock on soil water infiltration，the soil infiltration rate at different distances of outcropped bedrock was measured by single-loop infiltration method. [Methods] Taking the soil 20 and 100 cm away from the bedrock as the research objects，the characteristics of preferential flow were studied by the bright blue staining and tracing method. [Results] The capillary porosity and organic matter content of non-bedrock soil were significantly higher than those of bedrock soil（p<0.05），but the soil bulk density was significantly lower（p<0.05）. The infiltration parameters（initial，stable and average infiltration rate） of non-bedrock soil were higher than that of bedrock soil. The area of staining area and preferential flow path increased with the distance from the exposed bedrock. These results indicate that the infiltration capacity and preferential flow frequency of non-bedrock soils are stronger than those of bedrock soils. Rock surface roughness was an important factor affecting soil water infiltration process，and soil infiltration rate increased with the increase of rock surface roughness，and there was a very significant positive correlation between soil roughness and soil infiltration characteristics（p<0.01）. Kostiakov Model（R²=0.89），Horton Model（R²= 0.80）and Philip Model（R²=0.72）are the best fitting models for soil water infiltration process considering the influence of bedrock outcrop. [Conclusion] This study identifies the influence of exposed bedrock on soil infiltration characteristics and emphasizes the controlling role of rock surface roughness.

Abstract:[Objective] The impact of land use change on the evolution of ecological profit and loss under multiscenario simulation in Chaoyang was explored to provide a reference for the land space planning and ecological environment protection of the agro-pastoral ecotone in Northeast China. [Methods] Based on the land use data of Chaoyang in 2000，2010 and 2020，the Markov-PLUS model and ecological footprint model were used to analyze and predict the evolution characteristics of land use structure and ecological profit and loss of Chaoyang under four scenarios from 2000 to 2030. On this basis，the response of ecological profit and loss to land use change were explored by using the ecological elasticity model. [Results] 1）The land use change in Chaoyang from 2000 to 2020 was quite drastic. Cultivated land and grassland were the main types of land use，accounting for more than 80% of the total land area. 2）From 2000 to 2020，Chaoyang showed a change from ecological deficit to ecological surplus，with an overall increment of 273.07×10⁴ hm²，showing a spatial distribution pattern of high in the west and low in the east. The rapid increase of ecological carrying capacity of grassland，woodland and water area was the main reason for the increase of ecological surplus in Chaoyang. 3）Under four scenarios from 2020 to 2030，the ecological surplus of Chaoyang increased significantly，with ecological priority scenario（99.66×10⁴ hm²）> cultivated land protection scenario（98.93×10⁴ hm²）> natural development scenario（98.02×10⁴ hm²）> urban development scenario（97.87×10⁴ hm²）. The high-value area of ecological surplus migrated and expanded from west to east，while the low value-area concentrated in the urban center. 4）The ecological profit and loss of Chaoyang was elastic to land use change，and the ecological elasticity coefficient showed an increasing trend. [Conclusion] Land use change significantly affects ecological profit and loss. Optimizing land use structure can effectively improve regional ecological environment.

Abstract:[Objective] As newly constructed river and lake system interconnection projects，canals change the connectivity pattern of the river and lake system interconnection network. Furthermore，it affects the pathways of material，energy and risk across the network，but the mechanism by which newly constructed canals affect the the river and lake system interconnection network is not yet clear. [Methods] The area around Laizhou Bay was selected as the study area. The SWAT+model and graph theory method were employed to analyze the hydrological connectivity of the river and lake system interconnection network under two scenarios，with and without the canal. This was done to explore the differences in the impacts of canals on the various river basins，as well as on different types of water bodies，such as lakes，low-flow streams and high-flow streams. [Results] In comparison to other river basins，the hydrological connectivity of the Weihe River Basin and the Mihe River Basin is greater under the no-canal scenario，with the lowest degree of influence from the canal. The Yellow River-the Guangli River Basin and the Dagu River-the Jiaolai River Basin are influenced by the canal，and the greatest improvement is observed，with the values of betweenness centrality and closeness centrality indicators both increasing by more than 20 times. The impact of canals on the hydrological connectivity of diverse basins is largely contingent upon river network structure，the number and the location of canal connections. Low-flow streams exhibited the highest value of closeness centrality indicator，which is 3.4 times and 1.5 times the average value of lakes and high-flow streams，respectively. Lakes is the most affected by the canal，while low-flow streams are the least affected. This suggests that the lower the disturbance-resistant capacity of the water body，the more sensitive it is to the canal's response. The impact of canals on different water body types is dominated by the distance of the water body from the central water bodies of the network. [Conclusion] The planning of regional river and lake system interconnection networks should take into account growth mechanisms，including' preferential attachment' of betweenness centrality and anti-'preferential attachment' of closeness centrality. This will enable a more appropriate avoidance of the risk of unintended growth in hydrological connectivity.

Abstract:[Objective] To explore the variation of extreme precipitation in Xiangjiang River basin and its influencing factors on sediment transport. [Methods] Daily precipitation data from 13 meteorological stations in Xiangjiang River basin and its surrounding areas during 1965—2018 were collected， and seven extreme precipitation indices were selected and calculated using the RClimDex model. The spatial distribution characteristics were analyzed by linear fitting method and five-year moving average method，and the Cv value of each index，Spearman correlation coefficients and Kendall correlation coefficients were calculated. The temporal characteristics were observed from the linear exponential change and the five-year moving average process line. M-K mutation test，Lee-Heghinian test and ordered clustering method were used to test the mutation of the average annual sediment transport in Xiangjiang River basin. The contribution rate of extreme precipitation index to the variation of sediment transport during this period was quantitatively analyzed by double accumulation curve. [Results] 1）The interannual variation trend of extreme precipitation indices in the basin during 54 years showed an increasing trend except for CWD（consecutive wet days）. The duration of extreme precipitation events was prolonged，and the precipitation and precipitation intensity increased significantly. 2）The spatial distribution of each precipitation index was basically consistent with the topographic characteristics， and the trend was gradually increasing from the southwest to the northeast of the basin，and the maximum values of the seven indices were found at Nanyue Station. 3）Abrupt changes occurred in 1984 and 1997. During 1985—1997，the extreme precipitation index R99P（extremely wet days）had the greatest impact on the reduction of sediment transport in the basin，with a contribution rate of 10.5%. During 1998—2018，the same extreme precipitation index R95P（very wet days）had a change in the reduction of sediment transport. The contribution rate was 18.1%，but the influence of extreme precipitation index on sediment transport reduction was less than 20%. [Conclusion] Extreme precipitation has a certain effect on the reduction of sediment transport in the basin，but human activities are still the main factor leading to the reduction of sediment transport.

Abstract:[Objective] To assess the water conservation capacity of the upper Yellow River region，and to provide a scientific basis for the ecological protection and high-quality development of the Yellow River basin. [Methods] Taking Ningxia Province as a case area，the spatial and temporal evolution trend of the water conservation capacity of Ningxia Province from 1990 to 2020 was calculated based on the InVEST model，the Hurst index and the geodetector model， and its key influencing factors were identified. [Results] The land use pattern of Ningxia Province changed significantly，except for the unused land，all other land use types showed different degrees of increasing trends. The water conservation volume of Ningxia showed an increasing trend from 1990 to 2020，with an increase of about 0.009 mm/a. The spatial distribution pattern of the water conservation capacity showed a trend of“low in the north and high in the south”，and had a significant spatial clustering characteristic. The change of water conservation function in Ningxia was not sustainable，and would face the risk of degradation in the future. Precipitation was the main factor affecting the water conservation capacity of Ningxia，followed by elevation and slope，while vegetation cover and evapotranspiration had the lowest degree of influence. [Conclusion] The water conservation function and its sustainability of Ningxia Province recovered during the study period，but further enhancement of water conservation capacity is still needed to cope with future risk of degradation. The results of the study can provide a scientific basis for the construction of a pioneer area for ecological protection and high-quality development in the Yellow River Basin.

Abstract:[Objective] The aim of this study was to investigate the spatial and temporal variation of sediment transport in the Ganjiang River Basin，and to explore the contribution of climate change and human activities to sediment changes of the basin quantitatively，in order to provide a reference for soil erosion control，water and sediment resource management. [Methods] Data of sediment transport monitoring and precipitation history from 1960 to 2020 at 15 main hydrological observation stations located in upper，middle and lower reaches of the Ganjiang River Basin were collected. The spatial and temporal changes of sediment transport were analyzed by the linear trend method，Mann-Kendall trend test and Pettitt mutation test were used in combination with double mass curve to quantitatively analyze the contribution of the influencing factors. [Results] 1）Annual sediment transport in the upper，middle and lower reaches of the Ganjiang River Basin showed a significant decreasing trend from 1960 to 2020（|Z| >2.58）. The reduction rate of Waizhou，Xiajiang and four stations of the upper reaches were 2.143×10⁵，1.661×10⁵ and 0.812×10⁵ t/a，respectively，and there were mutations in sediment transport in 1994， 1992 and 1998. 2）The multi-year average sediment transport modulus of the sub-basins were high in the south and low in the north，and the temporal variation showed a trend of increasing first and then decreasing in the upper reaches，and decreasing in the middle and lower reaches. Compared with 1960—1987，the average sediment transport modulus in the upper，middle and lower reaches decreased by 51.32%，104.95% and 105.03%，respectively from 2001 to 2020. 3）The temporal and spatial variation of sediment load in the basin was affected by the topography，soil and water conservation measures，etc. Human activities were the leading factor for the reduction of sediment transport in the Ganjiang River Basin. [Conclusion] The sediment production from erosion in the Ganjiang River Basin has significantly reduced，but the upper reaches are still the key areas for soil erosion control in the future.

Abstract:[Objective] To investigate the elevation-based differentiation in moisture and nutrients of sedimentary layer in the water-level fluctuation zone（WLFZ）and provide a scientific basis for reservoir management. [Methods] The WLFZ of the Three Gorges Reservoir was selected as the research object and layered sample were collected from a representative slope. The particle size distribution，nutrient concentration，and moisture content were measured，and the differences in sediment properties at different elevations were analyzed. [Results] 1）The particles of the sediment in the WLFZ were relatively fine，with a median particle size ranging from 6.1 to 13.5 μm and an average of 8.7 μm. No significant difference in median particle size was observed among sediments at varying elevations（p>0.05）. The particle size distribution of the sediments was dominated by silt，with an average volume content of 82.7%，and the contents of clay and sand were 14.2% and 3.1%，respectively. 2）The mean total organic carbon（TOC），total nitrogen（TN），and total phosphorus（TP）contents of the sediments in the WLFZ were 18.82，1.24 and 0.75 g/kg， respectively. The stoichiometric ratios of carbon，nitrogen，and phosphorus（C∶N，C∶P，and N∶P）were 15.25， 25.26 and 1.68，respectively. Significant differences were observed in the overall trends of nutrient content changes with elevation. Specifically，TOC and TN contents increased significantly with increasing elevation（p<0.05），while TP content did not show a clear trend. The stoichiometric ratios of C∶P and N∶P in the sediments increased with increasing elevation，while the C∶N ratio showed no significant trend（p>0.05）. 3）The average mass water content of the sediments in the WLFZ was 28.63%，and no significant elevation-based spatial differentiation was observed（p> 0.05）. 4）The particle size distribution，nutrient content，and moisture content of sediments in the WLFZ were distributed in striated layers formed by alternating high and low values along the profile. [Conclusion] There is a significant elevation-based differentiation in the nutrient content of the sediments in the WLFZ of the Three Gorges Reservoir，but there is no significant spatial differentiation in particle composition and mass water content.

Abstract:[Objective] Taking the Pearl River source region，a typical karst area，as the research object，this study aimed to construct a reasonable ecological security pattern，analyze the evolution of the ecological security pattern from 1990 to 2020，and provide scientific support for strengthening biodiversity conservation and ecological restoration in karst regions. [Methods] Based on the evaluation of ecosystem service importance and ecological sensitivity，in combination with methods such as MSPA，MCR，and the gravity model，the ecological security pattern of the Pearl River source region from 1990 to 2020 was constructed，and its spatial-temporal evolution characteristics were analyzed. [Results] 1）Ecological sources were concentrated in the southern part of Qujing City and the border with Wenshan Prefecture，while they were scattered in the western part of Yuxi City，the border of Kunming City with Qujing City and Honghe Prefecture，the southern part of Honghe Prefecture，and the northeastern part of Qujing City. From 1990 to 2020，the area of ecological sources showed a trend of increasing first and then decreasing，and reaching a maximum in 2000. 2）The comprehensive resistance surface exhibited obvious spatial heterogeneity，and the area and range of high-resistance zones had been continuously expanding from 1990 to 2020. 3）In 1990 and 2000，55 ecological corridors were identified，which decreased to 45 in 2010 and 2020. Important ecological nodes were mainly distributed in ecologically sensitive areas such as the border of Qujing City，Yuxi City，and Honghe Prefecture. 4）The overall structure of the ecological security pattern in the Pearl River source region was consistent with the direction of rivers，but due to human activities，the ecological security pattern in the Nanpan River Basin was fragile. [Conclusion] Urbanization，land use change，and increased intensity of human activities are the main factors affecting the evolution of the ecological security pattern in the Pearl River source region. In the future，focus should be placed on protecting key ecological sources， restoring and constructing ecological corridors， developing eco-friendly industries， and establishing a comprehensive ecological monitoring network to improve the stability and sustainability of the karst ecosystem.

Abstract:[Objective] Based on the rational utilization of cotton straw resources，this study studied the effects of different amounts of cotton straw returning on soil physicochemical properties，nitrate-nitrogen leaching，nutrient invertase activity and cotton growth，in order to provide a theoretical basis for soil fertility improvement and sustainable agriculture development in drip-irrigated cotton fields in arid areas. [Methods] Four treatments were set up，including no returning（CK），half returning of cotton straw（50%ST），full returning of cotton straw （100%ST），and double returning of cotton straw（200%ST）. [Results] The proportion of large aggregates in soil was significantly increased by different rates of cotton straw returning to the field，and the increase under cotton straw returning to the field by 88.44% to 126.80% compared with no return. Meanwhile，cotton straw returning significantly increased the mean mass diameter and geometric mean diameter of aggregates， and enhanced the stability of aggregates. 50%ST，100%ST and 200%ST significantly decreased soil bulk density， increased soil porosity and soil water content，compared with CK，with soil water content being increased by 22.83% to 42.06%. Cotton straw returning to the field significantly increased the contents of soil organic matter， total nitrogen，alkali-hydrolyzed nitrogen，available phosphorus and available potassium. Compared with CK， 100%ST and 200%ST significantly decreased nitrate-nitrogen leaching in the 0—100 cm soil. The activities of soil urease and alkaline protease were significantly increased with the increase of cotton straw returning rate. 50%ST significantly increased cotton plant height， SPAD， Chl value， and dry matter weight. 50%ST， 100%ST，and 200%ST significantly increase the absorption of nitrogen，phosphorus，and potassium by cotton， thereby promoting the growth and development of cotton. Cotton straw returning significantly increased seed cotton yield by 4.61% to 12.59%，and nitrogen-use efficiency was significantly increased by 7.41% to 17.52%，compared with CK. [Conclusion] Cotton straw returning to the field can increase the proportion of large aggregates，reduce soil bulk density，increase soil porosity and water content，improve soil physical structure，and increase soil nutrient content，reduce nutrient leaching，thereby increasing the activities of soil nutrient convertases，promoting the growth and nutrient absorption of cotton，and improve the yield of seed cotton and nitrogen-utilization efficiency.

Abstract:[Objective] This study investigated the effects of regulated deficit irrigation on leaf nutrient levels （nitrogen，phosphorus，and potassium），enzyme activities（superoxide dismutase，peroxidase，and catalase），and root-zone soil nutrients（nitrate-nitrogen，available phosphorus，and available potassium）during the fruit expansion （Ⅲ）and coloration-sugar accumulation stages（Ⅳ）of citrus in western Hubei Province. [Methods] Six-year-old “Ehime 28”citrus trees in the western Hubei region were selected as the research subjects. Full irrigation served as the control（CK：daily irrigation volumes of 4.0 and 2.5 L during the fruit expansion stage（Stage Ⅲ ）and coloration-sugar accumulation stage（Stage Ⅳ ），respectively）. Four deficit irrigation treatments were applied during both Stage Ⅲ and Stage Ⅳ ，including mild deficit（LD：70% of CK），moderate deficit 1（MD1：55% of CK），moderate deficit 2（MD2：40% of CK），and severe deficit（SD：30% of CK）. The aim was to explore the response patterns of soil nutrients，citrus leaf nutrients，antioxidant enzyme activities，and root-zone soil nutrients to water stress under drip irrigation across different growth stages. [Results] 1） The Ⅳ -MD1 treatment significantly promoted the increase in leaf nitrogen，phosphorus，and potassium contents，with their respective mass fractions increasing by 8.05%，2.13% and 12.42% compared to the control group. Moreover，this treatment achieved the highest rates of nutrient accumulation and growth in the leaves. 2）The Ⅲ-MD1 treatment effectively enhanced the antioxidant defense capacity of citrus trees，with the activities of superoxide dismutase（SOD）and peroxidase（POD）increasing by 63.3% and 104.5%，respectively. 3）The Ⅲ-MD1 treatment markedly enhanced nitrate nitrogen and available phosphorus contents in the upper and middle soil layers，with respective increases of 74.54% and 17.61% in the upper layer，and 73.53% and 43.58% in the middle layer. Additionally，the IV-MD1 treatment significantly improved the vertical distribution of soil nutrients，effectively reducing nutrient leaching losses. This treatment also increased the available potassium content in the upper and middle soil layers by 59.23% and 51.67%，respectively. 4）Canonical correlation analysis revealed significant relationships between soil and leaf nutrient elements. Leaf phosphorus and potassium contents were positively correlated with available potassium in the soil，while they were negatively correlated with soil nitrate-nitrogen，available phosphorus，and leaf nitrogen. [Conclusion] The Ⅳ -MD1 treatment effectively promotes the accumulation of soil and leaf nutrients and enhances the activity of protective enzymes，making it a suitable water-saving management strategy for drip irrigation for citrus cultivation in western Hubei. The findings provide a theoretical basis for optimizing citrus irrigation practices and improving fruit quality.

Abstract:[Objective] We conducted a field experiment to investigate the effects of intercropping green manure crops and their combination with ground fabric mulching on soil moisture，fertility，and apple yield. [Methods] The main treatments included intercropping ryegrass（NGR），oilseed rape（NGO），and alfalfa（NGA），the sub-treatments included combining these intercropping modes with mulching ground fabric under apple trees（GR/GO/GA），and the control treatment was traditional clean tillage（CK）. Additionally，¹⁵N labeled microplots were set up within the main and control treatments. The responses of soil moisture，nutrients，and fruit yield were explored under the apple-green manure intercropping system. [Results] All treatments reduced soil water content（SWC）compared to CK，among which the decreasing range of GR（1.7%）was the smallest. Soil water difference ratio（SWDR）in the main treatments were all negative，among which NGR and NGA had the smallest（0.5%）and largest（4.7%） absolute value，respectively. All treatments increased evapotranspiration（ET）compared to CK，among which the increasing range of GR（0.3%）was the smallest. All treatments reduced soil nitrate-nitrogen（SNN）content， compared to CK. Compared to the sub-treatments，SNN and soil ammonium-nitrogen（SAN）contents in the main treatments increased by 6.8% and 5.4% on average. Intercropping green manure（NGR，NGO，and NGA） reduced ¹⁵N loss by an average of 56.4%（p<0.05），compared to CK，with alfalfa and ryegrass showing the highest （39.4%） and lowest （19.7%） ¹⁵N utilization efficiency， respectively. Compared to CK， ryegrass intercropping treatments（NGR and GR）increased SOM and TN contents by an average of 1.5% and 0.2%， respectively. In contrast，alfalfa（NGA and GA）intercropping treatments decreased SOM and TN contents by an average of 15.2% and 15.4%，compared to CK. Ryegrass intercropping treatments（NGR and GR）showed the highest fruit yield and water use efficiency，with an average increase of 12.1% in yield and 8.8% in water use efficiency，compared to CK（p<0.05）. [Conclusion] Adopting the binary mulching pattern（ground fabric mulching under apple trees+ryegrass intercropping between rows ）is beneficial to decreasing water consumption， nutrient loss，and increasing fruit yield and water use efficiency.

Abstract:[Objective] Robinia pseudoacacia，as the main afforestation tree species in China，plays an important role in improving the ecological environment and increasing carbon storage to alleviate climate change. This paper predicts the spatial and temporal changes of the suitable area distribution and carbon storage of Robinia pseudoacacia forest under different emission scenarios in the future， and analyzes its carbon sequestration potential， so as to provide scientific basis for regional plantation development planning and sustainable management. [Methods] Based on the MaxEnt model，this study predicted the potential suitable area of Robinia pseudoacacia under future climate scenarios， and the potential geographic distribution and area of Robinia pseudoacacia were studied quantitatively in the future. By analyzing the contribution rate of comprehensive environmental factors and the importance of substitution， the influencing factors restricting the potential geographical distribution of Robinia pseudoacacia plantation were clarified. The spatial distribution of carbon storage in 2090 s Robinia pseudoacacia forest was estimated and analyzed by using the volume stand age model and the volume biomass method. [Results] 1）Temperature factor was the most critical climatic factor affecting the distribution of potential suitable areas of Robinia pseudoacacia， with a contribution rate of 64.4%， precipitation factor came second. 2）Under the current climatic conditions，the potential suitable areas of Robinia pseudoacacia were mainly distributed in the Yellow River Basin，the Huaihe River Basin and the upper reaches of the Yangtze River，and the high suitable areas were mainly distributed in the northern part of China，accounting for about 4.2% of the total land area. Under the future climate change，the concentration of Robinia pseudoacacia loss area will increase under the SSP245 and SSP370 scenarios，mainly located in the Sichuan Basin. The expansion area was mainly distributed in the surrounding area of the stable zone，showing the characteristics of distribution fragmentation. 3）In the future，the carbon storage and carbon density of Robinia pseudoacacia forest will increase under the four climate scenarios. By 2100，the carbon storage will reach the maximum under the SSP585 scenario. [Conclusion] Under the high emission scenario，the medium-high value area of carbon storage moves northwestward and is concentrated in the eastern part of Northwest China.

Abstract:[Objective] Research on the characteristics of sap flow velocity and its responses to environmental factors in plantations with different degrees of degradation is helpful to reveal the mechanisms of forest degradation，and can provide a scientific basis for structure adjustment and management of regional plantations. [Methods] Taking Robinia pseudoacacia plantations in the east area of Yellow River in Ningxia as the research objects，the stem sap flow velocities of R. pseudoacacia with different degrees of degradation were measured by TDP thermal diffusion sap flow meter from May to October，2023，and the environmental variables were monitored at the same time. The response relationships between environmental variables and the stem sap flow velocities of non-degraded R. pseudoacacia plantation（NDPP），moderately degraded R. pseudoacacia plantation（MDPP）and heavily degraded R. pseudoacacia plantation（HDPP）were studied. [Results] 1）The daily average sap flow velocity of NDPP ，MDPP and HDPP were 2.32，0.84 and 0.45 cm/h respectively. 2）With the aggravation of degradation，the response threshold of R. pseudoacacia sap flow velocity to atmospheric temperature（Ta） and saturated water pressure deficit（VPD） increased，while the response threshold to solar radiation（Sr）decreased. The critical response thresholds of sap flow velocity of R. pseudoacacia with different degradation degrees to environment variables were 29.6，30.3 and 32.7 ℃ respectively in Ta，1.14，1.93 and 2.39 kPa respectively in VPD and 428，314 and 222 W/m² respectively in Sr. 3）The sap flow velocity of R. pseudoacacia decreased significantly with the decrease of soil water content， and the sensitivity of sap flow velocity to the change of soil water content decreased with the aggravation of degradation. 4）The contribution of environmental variables to sap flow velocity in stands with different degrees of degradation was different. With the aggravation of the degradation degree，the total effect of Sr，VPD and soil moisture on sap flow velocity decreased. [Conclusion] For degraded R. pseudoacacia forests，appropriate thinning could be used to reduce stand transpiration，improve rhizosphere soil moisture environment and increase the response sensitivity of trees to drought environment.

Abstract:[Objective] Investigating the ecological stoichiometry of soil nutrients and the driving mechanisms in wetlands can provide key insights into soil nutrient cycling processes and the internal driving factors. [Methods] This study focused on the wetlands of Banghu（semi-controlled lake）and Sizhoutou（open-water area）in the National Nature Reserve of Jiangxi Poyang Lake. Based on correlation analysis and structural equation modeling（SEM）， the ecological stoichiometric characteristics of surface soil carbon（C），nitrogen（N），and phosphorus（P）and their key influencing factors under different elevation gradients from 2017 to 2019 were analyzed. [Results] The mean concentrations of soil organic carbon（SOC），total nitrogen（TN），and total phosphorus（TP）in the Banghu wetland（9.33，1.18 and 0.43 g/kg，respectively）were significantly higher than those in the Sizhoutou wetland（2.65，0.31 and 0.19 g/kg，respectively）（p<0.05）. At the same elevation gradient，SOC，TN，and TP concentrations in both wetlands did not vary significantly over the years（p>0.05）. Although the mean soil C∶N ratio in the Banghu wetland（9.24）was significantly lower than that in the Sizhoutou wetland（10.19），the mean C∶P and N∶P ratios in the Banghu wetland（53.18 and 6.23，respectively）were significantly higher than those in the Sizhoutou wetland（40.90 and 4.05，respectively）（p<0.05）. Elevation gradient had no significant effect on the C∶N ratio in either wetland（p>0.05）. However，C∶P and N∶P ratios exhibited an increasing – decreasing trend along the elevation gradient. At the same elevation，C∶P in the Banghu wetland showed a significant interannual variation（p<0.05），while there was no significant change observed in the Sizhoutou wetland（p> 0.05）. Both wetlands exhibited significant positive correlations of C∶P and N∶P ratios with the aboveground biomass（AGB）and electrical conductivity（EC），and significant negative correlations with pH（p<0.05）. Soil alkaline nitrogen （AN）， ammonium-nitrogen （NH₄⁺-N）， and AGB had direct effects on soil ecological stoichiometry of both wetlands. In addition，the ecological stoichiometric characteristics in the Banghu wetland were directly influenced by soil bulk density（BD）and pH，while those in the Sizhoutou wetland were influenced by soil volumetric water content（SWC）and EC. In the Banghu wetland，AGB was the key factor influencing C∶N，while AN was the primary determinant of C∶P and N∶P. In the Sizhoutou wetland，NH₄⁺-N was the main controlling factor for C∶N，and AGB was the critical factor affecting C∶P and N∶P. [Conclusion] Vegetation biomass and soil nitrogen play crucial roles in the ecological stoichiometric characteristics of soil carbon，nitrogen， and phosphorus in the Poyang Lake wetlands. The soil stoichiometric values in the semi-controlled Banghu wetland are primarily driven by AGB and AN，whereas those in the open-water Sizhoutou wetland are mainly influenced by NH₄⁺-N and AGB. Therefore，technical model of vegetation restoration and reconstruction in wetlands could be considered to promote ecological restoration and protection of Poyang Lake wetland in the future.

Abstract:[Objective] The Loess Plateau is the largest apple-producing area in China. Due to serious aging of apple trees in recent years，the single variety structure，and the instability of China's grain market，it has become a common phenomenon for orchards to be transformed into farmlands on the Loess Plateau to ensure national food security. In order to study the response characteristics of the ecological stoichiometric ratios to conversion of orchards into farmlands. [Methods] Farmlands of 0 year（30 years orchard），1 year，3 years and 5 years old was selected as the research objects in this study，with farmlands cultivated with food crops set as the control group（CK）. Soil organic carbon（SOC），total nitrogen（TN），and total phosphorus（TP）contents in the soil of 0—100 cm depth （10 cm per layer，a total of 10 layers.）were measured，and their ecological stoichiometric ratios were calculated， and the influencing factors of the ecological stoichiometric ratios were analyzed. [Results] 1）With the increase of conversion years，the mean values of SOC and TN in 0—100 cm soil after orchards returning showed a trend of decreasing first and then increasing，and were higher than that in CK，but the mean value of TP in soil showed a decreasing trend. There was no significant change in C∶N in soil，but C∶P and N∶P increased gradually，while the mean values of C∶P and N∶P in farmlands after 5 years of tillage were higher than that in CK. 2）With the increase of soil depth，SOC，TN and TP in the soil of orchards with different returning years showed a downward trend as a whole. The C∶P and N∶P generally increased first and then decreased，while C∶N showed no obvious change pattern. 3）The soil particle composition was the main factor affecting soil nutrients and ecological stoichiometric ratios in the study area. [Conclusion] These results revealed the changed pattern of C，N and P in the soil of orchards of different ages after conversion into farmlands. The results will provide an important reference for ecological environment protection and sustainable development in the loess tableland area.

Abstract:[Objective] Clarifying the changes in net primary productivity（NPP）and the driving factors is of great significance to measure the carbon sequestration capacity of vegetation and support carbon sink trading. [Methods] Net primary productivity data were obtained based on MODIS-NPP data，and combining the Theil-Sen Median trend analysis，Mann-Kendall test，and the characteristics of spatiotemporal variation of NPP in Kunming from 2001 to 2020 were revealed. The optimal parameters-based geographical detectors（OPGD）model was adopted to explore the fluencing mechanisms of climate，topography and anthropogenic factors on NPP. [Results] 1）The annual mean distribution of vegetation NPP in Kunming City was spatially and temporally heterogeneous，with a distribution pattern higher in the west and lower in the east，and increased significantly at an average annual growth rate of 7.08 g/（m²·a）（C-based）. 2） The fragmentation degree of the vegetation landscape increased；the fragmentation degree was mismatched with vegetation NPP in terms of space，and it had a significant negative effect on the spatial and temporal distribution of vegetation NPP. 3）Changes in vegetation NPP were the result of the combined effects of climatic， anthropogenic and topographic factors； the kernel Normalized Difference Vegetation Index（kNDVI），land surface temperature，and vegetation landscape fragmentation had stronger explanatory power than factors such as temperature，precipitation，and slope；and the interactions between the factors better explained the spatial and temporal changes in vegetation NPP. [Conclusion] The vegetation NPP in Kunming showed an increasing trend from 2001 to 2020 in general. However，the ecological situation in certain areas of the main urban districts is not optimistic. In the future，comprehensive planning should be implemented to scientifically promote the coordinated development of ecological protection and social economy.

Abstract:[Objective] To explore the effects of grazing on soil enzyme activities in salinized grasslands during the freezing period under the background of global warming. [Methods] Taking salinized grasslands in the Hexi Corridor as the research objects，four treatments were set up，including control（CK），grazing（FCK），warming （W），and warming + grazing（FW），in order to explore the variation law and spatial distribution characteristics of soil enzyme activities under different treatments. [Results] Compared with CK， the FCK treatment significantly increased soil water content and total nitrogen content，and decreased soil organic carbon content. The W treatment reduced soil water content and increased soil organic carbon content and total nitrogen content by 97.61% and 16.89%，respectively. The FW treatment significantly increased soil water content，organic carbon content and total nitrogen content， while total phosphorus content of the FW treatment was significantly （40.81%）lower than that of CK. The FCK treatment significantly increased the activities of β-glucosidase， amylase，urease and phosphatase；the W treatment significantly increased the activities of amylase，urease and nitrite reductase，while the FW treatment increased the activities of β -glucosidase，amylase，urease and nitrate reductase. Compared with other treatments，the stoichiometric ratios of soil enzymes in W and FW treatments were significantly increased. Through vector analysis，it was found that the study area was significantly limited by nitrogen. [Conclusion] Warming and grazing treatments directly or indirectly affect soil enzyme activities through soil physicochemical properties，of which SOC is one of the key factors affecting soil enzyme activities in salinized grasslands in Hexi Corridor.

Abstract:[Objective] To investigate the effects of microbial fertilizer application under brackish water irrigation on salt ion content in saline soil and on the growth of Lycium barbarum，as well as to elucidate the relationship between soil salt ions and Lycium barbarum growth indices. [Methods] A series of field experiments were conducted on moderately saline soils in the Hetao Irrigation Area. Four different application rates of microbial fertilizer were tested under brackish water irrigation conditions：F1（45 kg/hm²），F2（75 kg/hm²），F3（105 kg/hm²），and F0（0 kg/hm²，as control）. [Results] Soil salt ion levels declined with increased microbial fertilizer application. Notably，compared to F0，the F3 treatment significantly reduced Na⁺ ，K⁺ and Cl ^- levels by 49.22%，40.20%，and 47.80%， respectively，throughout the reproductive period（p<0.05）. Additionally，plant height，ground diameter，canopy width，and new branch growth rate in LBP significantly increased with higher microbial fertilizer levels（p< 0.05），with the F2 treatment yielding the greatest improvements. During the flowering stage—a period highly sensitive to growth—the plant height growth rate in F2 exceeded that of F0 by 3.27%. In the spring growth period，the growth rates of plant height，canopy width，and new branches all peaked，while the growth rate of ground diameter reached its highest in the fruit expansion stage. The Lycium barbarun yield in the F2 treatment was 46.33% higher than that in F0（p<0.05），with a fertilizer partial productivity of 0.61 kg/kg. Correlation analysis indicated a negative relationship between soil Na⁺ ，K⁺ and Cl ^- concentrations and Lycium barbarum growth parameters. [Conclusion] In summary，to optimize soil conditions and promote Lycium barbarum growth in saline soils under brackish water irrigation in the Hetao Irrigation District，a microbial fertilizer application rate of 75~105 kg/hm² is recommended.

Abstract:[Objective] To reveal the spatiotemporal evolution，distribution dynamics，spatial differences，and convergence characteristics of land green use efficiency in resource-based cities，in order to clarify the land use status，optimize the national spatial development pattern，and provide a reference for comprehensive green transformation of economic and social development. [Methods] Based on data from 114 resource-based cities in China from 2006 to 2020，the spatial and temporal characteristics，distribution dynamics，spatial differences，and convergence features of land green use efficiency in resource-based cities were analyzed by using the super efficiency SBM model to measure land green use efficiency，in combination with Kernel density estimation， Dagum Gini coefficient，coefficient of variation，and fixed effects model. [Results] 1）Overall，the land green use efficiency in resource-based cities showed a fluctuating upward trend，with an average annual growth rate of 1.363% during the investigation period. From a regional perspective，the land green use efficiency showed a pattern of regional differences in most years，with the eastern region>northeast region>central region>western region. From the perspective of growth stages，there was a gradient difference characteristic of regenerative type> maturity type>growing type>declining type. From the perspective of spatial distribution，the land green use efficiency of most resource-based cities was in the middle to low range，and showed obvious spatial agglomeration and non-equilibrium characteristics. 2）In terms of dynamic evolution，the core density curves of cities in the overall and various growth stages were fluctuating to the right，with a decrease in height and an increase in width of the main peak，a significant right tail，and a gradually emerging multi-peak shape，indicating an improvement in land green use efficiency. However，there was significant downward pressure，increasing inequality，and a certain degree of divergence and polarization. 3）From the perspective of spatial differences，the spatial differences in land green use efficiency within and between resource-based cities at different growth stages were on the rise. Regional differences and over-density were the two main sources of overall differences. 4）According to the convergence test，during the investigation period，the overall and different growth stages of resource-based cities' land green use efficiency did not show σ-convergence，indicating that regional differences were expanding. However，at the same time，there was a significant trend of absolute β-convergence and conditional β-convergence，that is，the growth rate of land green use efficiency tended to converge and gradually develop towards a steady state. [Conclusion] In the future，we should scientifically understand the connotation，scope，and practical value of land green use efficiency， optimize land use policies， coordinate and adapt to local conditions， in order to comprehensively improve the land green use efficiency of resource-based cities.

Abstract:[Objective] To construct a comprehensive multi-temporal landslide inventory across the Eastern Himalayan Syntaxis and quantify landslide-driven erosion rates，thereby revealing the geomorphological significance of landslide processes in this region. [Methods] The Particle Swarm Optimization（PSO）algorithm was employed to detect the change of the Normalized Difference Vegetation Index（NDVI）from remote sensing images，and a multitemporal landslide inventory for the Eastern Syntaxis from 1987 to 2021 was constructed. The landslide erosion rate was calculated using an empirical landslide area-volume relationship. Additionally，the factors inducing landslide processes by considering climatic and topographic parameters were explored. [Results] A total of 1 323 landslides were identified in the study area between 1987 and 2021，with the highest occurrence of 389 landslides recorded between 2017 and 2021. The landslides predominantly occurred on both sides of the river valleys near the Yarlung Tsangpo River's Great Bend. The landslide erosion rates in the study area ranged from 0 to 76.06 mm/a，with an average rate of 0.44 mm/a. These rates showed a decreasing trend from the Great Bend section of the Yarlung Tsangpo River outward. The erosion rates were comparable to the exhumation rates of geological-scale rock bodies and the millennial-scale basin-wide average erosion rates. Landslide occurrences were associated with rainfall events and seismic activities，primarily developing on south-facing slopes and clustering within an elevation range of 1 500 to 3 000 meters and slopes of 35° to 45°. [Conclusion] Landslides represent the dominant erosion process in the Eastern Himalayan Syntaxis. Rainfall is influenced by the windward slope effect and concentrates on southfacing slopes，and drives the concentrated distribution of landslides on these slopes. Moreover，precipitation also triggers landslides by enhancing river incision，which steepens the adjacent slopes.

Abstract:[Objective] To explore the impact of different vegetation types on soil health in the Qinling region，to assess the relationship between aboveground plants and soil health，and construct a comprehensive soil quality health evaluation model. [Methods] Five vegetation types were selected，including poplar forest（RY），pine forest（RP），mixed forest （RM），privet forest（RL），and vineyard（CK）. Soil samples were collected from different depths（0~20 cm and 20~ 40 cm），and the analysis was conducted using the Minimum Data Set（MDS）method combined with 35 soil physical， chemical，and biological indicators，along with the contents of four heavy metals. [Results] 1）The Minimum Data Set （MDS）was established for soil fertility evaluation，eight biological and non-biological indicators were included，i.e.，field moisture capacity（FMC），physical clay content，pH，soil organic carbon（SOC），microbiological total PLFA， eukaryotic microbial PLFA，nitrogen acquisition enzyme（NAG），and microbial biomass nitrogen（MBN）. Potential Ecological Risk Index（RI）was used to assess the pollution risk of four heavy metals for soil environmental risk evaluation. Soil health was assessed by combining MDS and RI. 2）Soil fertility of RY was significantly higher than that of RP and RM. The lower SOC，NAG，FMC，and eukaryote significantly limited soil fertility，while the higher heavy metal pollution risk in CK severely restricted its soil health rating. 3）There were significant differences in soil health at different depths，indicating that the diversity of surface herbaceous plants increased soil fertility and reduced heavy metal pollution，significantly impacted soil health. [Conclusion] Reasonable reclamation measures and increased diversity of surface vegetation can significantly improve soil health. The restoration of reclamation vegetation can help improve soil fertility and reduce heavy metal pollution. It is recommended to strengthen the diversity of herbaceous plants in future reclamation processes and increase fertilization to improve soil ecosystem functions and health levels.

Abstract:[Objective] To investigate the effect of applying Pteroceltis tatarinowii biochar on the remediation of soil with combined contamination of Cu and Pb by Chlorophytum comosum. [Methods] Taking the farmland soil with combined contamination of Cu and Pb around the copper tailings in Laoyaling，Tongling City as the research object，pot planting test method was used to grow C. comosum in the soil with different mass ratios of Pteroceltis tatarinowii biochar（1%，3%，5%，7% and 10%）. The pots without adding P. tatarinowii biochar were taken as the blank group，and the pots without planting C. comosum were set as the control group. The effects of different mass ratios of P. tatarinowii biochar on remediation of Cu- and Pb-contaminated soil by C. comosum were studied，and the potential of P. tatarinowii biochar in enhancing the remediation of Cu- and Pb-contaminated soil was evaluated. [Results] Plant height，root length and underground fresh weight of C. comosum were significantly increased by adding P. tatarinowii biochar. Soil pH， organic matter， total nitrogen， available phosphorus and available potassium were significantly increased. The mass fractions of available Cu and Pb in soil were significantly decreased，and the uptake of Cu and Pb by C. comosum was significantly increased. The maximum increases of Cu and Pb in the above-ground part are 51.39% and 59.77%，respectively，and the maximum increases of Cu and Pb in the undergroud part are 15.63% and 45.46%，respectively. The maximum enrichment and transfer coefficients were 0.61 and 0.40 for Cu and 0.37 and 0.68 for Pb，respectively. The relative abundances of Acidobacteria and Proteobacteria were decreased，while the relative abundances of Chloromycetes and Bacteroidetes were increased，and the soil nutrient metabolism was promoted. [Conclusion] Combined application of P. tatarinowii and C. comosum has better remediation effect.

Abstract:[Objective] This study aimed to investigate the spatiotemporal changes and trade-offs/synergies of ecosystem services within the Beiluo River basin to provide a scientific foundation for rational resource allocation and sustainable development. [Methods] Utilizing multi-source data and models，such as InVEST and CSLE，to quantitatively assess and analyze the spatiotemporal variations and trade-offs/synergies of three key ecosystem services-water yield，soil conservation，and carbon storage-across different periods. These periods include the relatively stable land use period from 1970 to 1990，the transitional period around 2000，and the ecological restoration period from 2010 to 2020. [Results] 1）The overall water yield of the basin initially showed an increasing trend，followed by fluctuating decline，bottoming out in the 2000. During the first period，the average water yield was 10.16×10⁸ m³（37.75 mm），which decreased by 36.9% during the second period and by 25.53% during the third period compared to the initial period. Among the three land use types of forests，cropland，and grassland，the total water yield and water yield depth of cropland are always the highest，while the water yield depth of forest was always the lowest. 2）The total soil conservation displayed an upward trend with fluctuations， peaking in the 2010. Over the first period，the average annual soil conservation was 305.62×10⁶ t（113.57 t/ hm²），which increased to 364.52×10⁶ t in the transition period and significantly increased to 426.19×10⁶ t （157.75 t/hm²）during the third period. The soil conservation capacity of forests was significantly greater than that of cropland，and the construction of terraces and other engineering measures have greatly enhanced the function of cropland. 3）The total carbon storage remained stable and then continued to increase，with a notable increase from the 2000 onwards，and a 24.09% increase in the 2020 when compared with the 1970. Forests were the main carbon reservoirs，with their carbon storage significantly increasing，whereas that in grassland and cropland have decreased due to the reduction in their areas. 4）Regarding changes in the spatial pattern，the areas experiencing a decrease in water yield and an increase in soil conservation and carbon storage were mainly concentrated in the high plateau and gully areas，as well as the hilly and gully regions. 5）At the basin scale，there was a trade-off between water yield and soil conservation，as well as carbon storage. Soil conservation and carbon storage，however， exhibited a synergistic relationship. The degree of synergy between soil conservation and carbon storage decreased over time，while the trade-off between water yield and the other two remained relatively stable. [Conclusion] With the restoration of vegetation，the three key ecosystem service exhibited significant temporal and spatial variation characteristics，possessing relatively stable trade-off and synergistic relationships. The research results can provide a scientific basis for enhancing the comprehensive benefits of ecosystem services on the Loess Plateau.

Abstract:[Objective] The investigation of temporal and spatial variations in soil erosion and its influencing factors in Yunlong County is of great significance for the advancement of featured agriculture，management and restoration of ecological environment，and soil erosion control in alpine and canyon regions. [Methods] The GIS and RUSLE model were employed to simulate the spatiotemporal evolution characteristics of soil erosion in Yunlong County from 2000 to 2020. The relationship between featured agriculture and soil erosion was analyzed. By considering influential factors such as elevation，slope，annual average rainfall，vegetation coverage，and land use type，the quantitative attribution of soil erosion was examined using a geographic probe model. [Results] 1）From 2000 to 2020，the average erosion modulus in Yunlong County exhibited a decreasing trend across five stages（each stage included five years），being 1 644，1 085，878，661 and 467 t/（km²·a），respectively，and the overall soil erosion shifted from moderate to mild intensity. 2）Over the past 20 years，there was a significant increase in proportion of the area where soil erosion had been improved，with an increase of 48.45%，while the proportion of area experiencing soil erosion deterioration only increased by 4.23%， indicating an overall trend of decline and improvement in erosion grades. 3）Soil erosion in Yunlong County was predominantly concentrated within the elevation range of 2 000~2 500 m and slopes between 15°~25° . 4）The soil and water conservation capacity of typical featured agriculture in Yunlong County followed the order of pickled walnut>Chinese herbal medicine under the forest>ecological green tea>Maidiwan pear. 5）The influencing factors for soil erosion in Yunlong County ranked as the order of vegetation coverage > altitude > slope > annual average rainfall>land use type， with the corresponding q values being 0.401 0，0.142 0，0.117 5，0.115 9 and 0.046 6，respectively. Notably，the interaction between vegetation coverage and slope exhibited the strongest explanatory power with a q value of 0.82. [Conclusion] Overall soil erosion in Yunlong County has shown effective improvement over a span of two decades. During this period，there had been a weakening trend in soil erosion accompanied by an increase in vegetation coverage. Future attention should be directed towards monitoring changes in soil erosion within altitudes ranging from 2 000~2 500 m and slopes between 15° ~25° in Yunlong County while ensuring proper implementation of measures to develop featured agriculture and restore the microtopography on slopes to mitigate risks associated with further deterioration of soil erosion.

Abstract:[Objective] To reveal the characteristics of the response of runoff to land use and climate change in the Tao'er River basin，and to predict the future evolution of runoff in the basin. [Methods] Taking the Tao'er River basin as the study area，the runoff response process of the watershed was quantitatively analyzed based on the SWAT model with the CMIP6 climate model and PLUS model driving meteorological and land use changes， respectively，to project development scenarios for 2025—2100. [Results] 1）The SWAT model had an R²>0.75 and an NSE>0.65 for both the rate period and the validation period. The overall accuracy of the PLUS model was > 0.85，and the Kappa coefficient was > 0.80，and the two models had good applicability in this watershed. 2）Relative to the baseline period（1990—2022），the Tao'er River Basin received higher precipitation under all three future scenarios than during the historical period，as shown by SSP126 > SSP585 > SSP245，and higher temperatures under all three future scenarios than during the historical period，as shown by SSP585 > SSP245 > SSP126. 3）During the period of 2025—2100，the areas of cropland，watersheds，and unutilized land in the Tao'er River Basin increased significantly，while the area of forested land increased slowly，and the areas of grasslands and built-up lands continued to decrease. 4）The average annual runoff in the future period would exceed the level of the base period under the SSP126 scenario，while it would be lower than the level of the base period under the SSP245 and SSP585 scenarios，and the average multi-year runoff under the three scenarios would be 11.17×10⁸，9.00×10⁸ and 9.34×10⁸ m³/s. [Conclusion] The Tao'er River basin's future runoff change presents the trend of continuous growth，therefore should enhance the flood control consciousness when the annual average runoff reaches the maximum value in three level years，the results can provide certain reference basis for reasonable development and construction of the Tao'er River basin in the future.