Abstract:[Objective] The spatial distribution characteristics of physicochemical properties under different vegetation restoration measures were analyzed in order to provide a theoretical basis for vegetation restoration in semi-arid sandy areas. [Methods] Three typical restoration models 〔enclosed grassland (EG), aerial seeded woodland (AS), and artificial Caragana korshinskii woodland (AK)〕 were compared against a degraded grassland (CG) used as control in the Southwest Mu Us sand land. Soil physicochemical indexes and a comprehensive soil fertility index in the 0—40 cm soil layer were analyzed. [Results] ① Soil water content (SWC) in the 0—10 cm layer significantly increased under the three different vegetation restoration measures, but decreased significantly in the 10—40 cm layer. In contrast, soil bulk density (BD) in the 0—10 cm layer decreased significantly, but there was no significant difference in 10—40 cm layer, which showed weak variation. Vegetation restoration significantly reduced soil pH value in the 0—20 cm layer, but showed no significant difference in the 20—40 cm layer. In addition, SWC, BD, and pH value increased as soil depth increased under the same vegetation restoration measure. ② Soil organic matter (SOM) and total nitrogen (TN) increased significantly, while available phosphorus (AP) decreased significantly under different vegetation restoration measures. SOM was highest in EG, but TN was highest in AS. Total phosphorus (TP), SOM, and TN exhibited surface aggregation in the soil. AP and available nitrogen (AN) were different for different restoration measures and soil layers. ③ The soil comprehensive fertility index followed the order of AS (0.794)>EG (0.662)>CG (0.637)>AK (0.603), indicating that soil quality was highest in AS, but lowest in AK. [Conclusion] Various vegetation restoration measures had significant effects on soil physiochemical properties, and resulted in different variations in soil indexes in the vertical soil profile. Aerial seeding is suitable for afforestation, while large area artificial Caragana korshinskii woodland is not suitable for the Mu Us sand land.

Abstract:[Objective] The suitable soil amendments applied to soda saline alkali cultivated land in the Xiliaohe Plain of Inner Mongolia were screened in order to provide a theoretical basis for the comprehensive development and utilization of saline alkali land and the sustainable development of agriculture in this area. [Methods] Three soil amendments (i.e., organic silicon fertilizer, humic acid fertilizer, and microbial fertilizer) were selected to analyze their effects on soil pH value, alkalinity, total salt content, organic matter content, sugar beet growth, yield, and quality of soda salinized cultivated land. [Results] ① The three soil amendments improved the soil chemical properties of soda salinized cultivated land to varying degrees. Specifically, they effectively reduced soil pH value, alkalinity, and total salt content, and increased organic matter content. Soil pH value, alkalinity, total salt content, and organic matter content of different treatments in the 10—20 cm soil layer were greater than that in the 0—10 cm soil layer. Compared with the control, the reduction range of soil pH value and alkalinity, and increase range of organic matter content of the three soil amendments in 10—20 cm soil layer were greater than in the 0—10 cm soil layer, while the reduction range of soil total salt content in the 0—10 cm soil layer was greater than in the 10—20 cm layer. Among the three soil amendments, organic silicon fertilizer had the greatest effect on increasing soil pH value, alkalinity, total salt content, and organic matter content. ② Compared with the control, the three soil amendments significantly increased emergence rate and survival rate of sugar beet, and increased growth indexes such as plant height, leaf area index, and whole plant fresh weight of sugar beet, thereby improving sugar beet yield and quality, and the organic silicon fertilizer showed the best effects. The three soil amendments increased the output value of sugar beet, but the economic benefit of only organic silicon fertilizer was higher than that of the control. ③ The main factors affecting the emergence, survival, growth, yield, and quality of sugar beet in soda saline alkali cultivated land were soil pH value, alkalinity, total salt content, and organic matter content. The application of soil amendments can directly regulate soil chemical characteristics, thereby effectively ensuring sugar beet growth and development, and increasing yield and quality. [Conclusion] From the comprehensive consideration of soil characteristics, sugar beet growth, yield, quality, and economic benefits, the organic silicon fertilizer was more effective in improving of soda saline alkali cultivated land and sugar beet cultivation compared with the other two soil amendments.

Abstract:[Objective] The poor structure and low fertility of reclaimed soil of abandoned homesteads in hollow villages in the loess area were addressed in order to provide a theoretical basis for improving the quality of reclaimed soils. [Methods] The effects of six different treatments of modified materials on structural stability and soil organic matter (SOM) of a reclaimed soil were compared with a control (CK) treatment in a five-year field experiment. The modified materials treatments were maturing agent (TM), fly ash (TF), organic fertilizer (TO), maturing agent + fly ash (TMF), maturing agent + organic fertilizer (TMO), and fly ash + organic fertilizer (TFO). [Results] SOM content was significantly increased (compared with CK) after the application of the different modified materials that promoted the cementation and aggregation of water-stable microaggregates (<0.25 mm) into water-stable macroaggregates (>0.25 mm). The content of water-stable macroaggregates showed an increasing trend. In the 0—15 cm soil layer, the contents of water-stable macroaggregates under TM, TF, TO, TMF, TMO, and TFO were increased by 328.2%, 130.0%, 87.8%, 81.1%, 36.7%, and 12.2%, respectively, compared with CK. Moreover, the application of the TF, TO, TMF, TMO, and TFO treatments significantly increased the mean weight diameter (MWD) and geometric mean diameter (GMD) of soil aggregates, while the unstable-aggregate index (E_LT) and fractal dimension (D) were decreased (p<0.05). SOM content was significantly positively correlated with MWD, GMD, and >2 mm water-stable aggregates, and significantly negatively correlated with the E_LT, D, and water-stable microaggregates. In particular, reclaimed soil under TFO had the highest content of SOM and water-stable macroaggregates, and the best effect on improving soil structrual stability. [Conclusion] Using a combination of organic fertilizer and fly ash is an appropriate practice to improve reclaimed soil structure and fertility of abandoned homesteads in hollow villages in the loess region.

Abstract:[Objective] The influence of topography and land use on the soil erosion rate of dam-controlled catchments was analyzed in order to provide a theoretical basis for soil erosion control and soil and water conservation measures in a loess hilly and gully region. [Methods] A high-resolution digital elevation model (DEM) and image data for catchments were obtained by use of unmanned aerial vehicle (UAV) photogrammetry technology. Topographical factors and land use of the catchments were accurately extracted. Partial least squares regression was used to determine the impact and relative importance of topography and land use on soil erosion rate in dam-controlled catchments. [Results] The variation range of soil erosion rate in dam-controlled catchments was 2 869~14 191 t/(km²·yr), with an average value of 9 984 t/(km²·yr). Differences existed in topographic and land use factors in dam-controlled catchments. Significant correlations (p＜0.01) were observed between LS factor and L factor; connectivity index (IC) and topographic wetness index (TWI); catchment area (A) and watershed length (BL) and shape factor (Ff). From the partial least squares regression of soil erosion rate, the maximum VIP value was detected for the slope length factor (VIP=1.66; RCs=0.30), followed by topographic wetness index (VIP=1.62; RCs=0.25), LS factor (VIP=1.43; RCs=0.27), connectivity index (VIP=1.39; RCs=-0.19), percentage of agricultural area (VIP=1.03; RCs=0.10), and percentage of grassland area (VIP=1.03; RCs=-0.10). [Conclusion] There were significant differences in soil erosion rate in the dam-controlled catchments. Slope length factor, LS factor, topographic wetness index, connectivity index, percentage of agricultural area, and percentage of grassland area were important factors influencing soil erosion rate, with all having VIP values greater than 1.

Abstract:[Objective] The microbial mineralization reinforcement and erosion resistance of loess slope were studied in order to provide technology for the prevention and control of slope soil erosion in this region. [Methods] Microbial mineralization technology was used to reinforce a loess slope. The mechanism of microbially induced calcite precipitation (MICP) technology on the mineralization and reinforcement of a loess slope was determined from a microscopic point of view with the use of an optical microscope and a scanning electron microscope. Erosion resistance of the reinforced slope was analyzed combined with an indoor simulated rainfall test. [Results] The erosion resistance of a loess slope could be effectively improved by using microbial mineralization technology to solidify the loess slope. As curing times increased, the thickness of the cured layer gradually increased. The permeability of the slope gradually decreased, and the total production flow gradually increased from 38.5 to 44.4 L/h, with an increase ratio of 15.6%. At the same time, total sediment yield gradually decreased from 480.64 to 17.1 g/h, with a decrease of 96.5%. No obvious soil erosion occurred on the slope after seven solidification treatments and one hour of continuous scouring with a rainfall intensity of 120 mm/h. The runoff and sediment concentration on the slope hardly changed with increased rainfall duration, and were stable between 0.72 and 0.74 L/min and between 0.001 and 0.002 g/ml, respectively. When the number of curing treatments reached seven or more, the number of curing treatments had a significant effect on total sediment yield, and total sediment yield decreased with increasing number of curing treatments. [Conclusion] MICP technology provides a new method and technology for reinforcement of loess slopes in the loess hilly and gully region that will prevent and control soil erosion on temporary and permanent slopes. This technology would be certain to have practical applications.

Abstract:[Objective] The root distribution characteristics of Hippophae rhamnoides ssp. sinensis, Hippophae rhamnoides ssp. taiyang, and H. rhamnoides ssp. mongolica “Wulanshalin” in a feldspathic area, and the characteristics of soil erosion resistance under the forests were analyzed in order to provide new tree species options for improving the local ecological environment. [Methods] The soil profiles were excavated in the field to obtain the root-soil complexes, and the root scanning and disintegration test were performed indoors. [Results] ① The vertical distribution patterns of roots for the three seabuckthorn species were similar. Root length and root volume gradually decreased with increasing soil depth, and roots were mainly located in the 0—60 cm soil layer, accounting for 90.96% of the total root amount for H. rhamnoides ssp. sinensis, 83.38% for H. rhamnoides ssp. taiyang, and 74.93% for H. rhamnoides ssp. mongolica “Wulanshalin”. Thick roots were mainly located in the 0—40 cm soil layer. The thick roots in the horizontal direction were mainly located in the range of 0—20 cm from the base of the plant, and the fine roots were mainly located in the range of 20—100 cm. The farther away from the base, the fewer the fine roots. The overall root system was distributed in a shallow layer. ② The change trend of soil disintegration rate under the H. rhamnoides forest was basically the same. The average disintegration rate of the surface soil at 0—20 cm was the lowest, and the rate gradually increased with increasing depth. In the horizontal direction, the farther away from the base of the plant, the greater the average disintegration rate of the soil. The soil disintegration rate followed the order of: H. rhamnoides ssp. sinensis (3.18 g/s)> H. rhamnoides ssp. taiyang (1.27 g/s)> H. rhamnoides ssp. mongolica “Wulanshalin” (1.21 g/s). ③ There was a significant correlation between soil disintegration rate and root distribution of seabuckthorn. In the vertical direction, it was affected by both coarse and fine roots, while in the horizontal direction, it was mainly affected by fine roots, which have a greater effect on soil and water retention. [Conclusion] The root content of H rhamnoides ssp. taiyang was higher than that of H rhamnoides ssp. mongolica “Wulanshalin”, and the root distribution characteristics were more closely related to the change law of soil disintegration rate under the forest, which is more suitable for soil erosion prevention and control in the soft sandstone area.

Abstract:[Objective] The family and genus composition, life forms, water ecotypes, conservation plants, and resource plants among the plants in the Alxa Plateau desert area were analyzed in order to provide a basis for the rational development and utilization of desert plant resources, biodiversity protection, and ecological environment restoration on the plateau. [Methods] The composition of families and genera, life forms, water ecotypes, and special species of desert plants were analyzed through a vegetation survey and access to relevant information in the Alxa Plateau. [Results] There were 727 species of plants belonging to 284 genera and 70 families in the Alxa Plateau. Perennial herbs were the most common plant life forms, followed by annual herbs, biennial herbs, and shrubs. Mesophytes were the most abundant water ecotype, followed by xerophytes and mesoxerophytes. There were 24 national and autonomous regional protected plants, with 26 International Union for Conservation of Nature (IUCN) red list plants. Moreover, there were 210 medicinal plants and 186 forage plants. [Conclusion] In the desert area of the Alxa Plateau, Asteraceae, Chenopodiaceae, Fabaceae, and Poaceae were the dominant families, while Astragalus, Saussurea, and Artemisia were the dominant genera. Most plants were perennial herbs. Plants exhibited obvious xerophytic characteristics. There were many rare and endangered plant species, and there were abundant resource plants. In order to rationally use plant resources, it is necessary to manage and protect them according to their existing status and value type.

Abstract:[目的] 研究柴达木盆地西南缘沙丘沉积物粒度特征及其沉积环境，为格(尔木)库(尔勒)铁路防沙和安全运行提供基础数据支撑。[方法] 通过粒度分析方法对柴达木盆地西南缘沙丘区沙丘沉积物的粒度特征及沉积环境进行分析。[结果] 柴达木盆地柴西南沙区沙丘表层沉积物以细沙为主，中沙次之，平均粒径-0.14~3.49Φ，平均值为2.02Φ；分选系数为0.32～1.59，平均值为0.69，以分选较好和好的沙粒为主；偏度主要为近对称分布；峰度以中等峰态占优。自然频率分布曲线呈单峰和双峰分布模式，累积频率曲线图式为一段式、二段式、三段式。平均粒径与分选系数呈线性相关关系，即随平均粒径变细，分选逐渐变好。当峰度＜0.9时，平均粒径与峰度呈负相关；当峰度＞0.9时呈正相关。[结论] 柴达木盆地西南沙区西北部为风成环境，以风成沙为主；而东南部以湖相和河流冲—洪积环境为主，沙物质受到风力和流水的交互作用。

Abstract:[Objective] The diversity of typical shrub communities in the ecotone of the Ulan Buh-Western Ordos Steppe Desert was researched in order to provide a theoretical basis for protecting biodiversity and for ecological environment construction in the area. [Methods] A vegetation survey was carried out by setting up sample sites of representative community types in the area. The community types, species composition, community characteristics, and species diversity of the main shrub communities in the ecotone were analyzed. [Results] There were 12 families, 30 genera, and 36 species of plants in the area, among which there were more Fabaceae, Chenopodiaceae, Asteraceae, and Poaceae, and more single species. Plants were mainly composed of shrubs and perennial herbs. Most plants were xerophytes. The shrub communities included the Krascheninnikovia ceratoides community, the Scarcozygium xanthoxylon community, and the Tetraena mongolica community in the Western Ordos Steppe Desert, and the Nitraria tangutorum community, the Artemisia ordosica community, and the Ammopiptanthus mongolicus community in the Ulan Buh Desert. The plant density of the shrub community was higher in the Western Ordos Steppe Desert. The importance value, coverage, and aboveground biomass of the shrub community were higher in the Ulan Buh Desert. The species diversity of the shrub communities in the Western Ordos Steppe Desert was generally higher than in the Ulan Buh Desert. The similarity of most communities was low. [Conclusion] The total number of plants in the Ulan Buh-Western Ordos Steppe Desert was relatively few. Perennial herbs and shrubs were the main types of plants in the ecotone. The plants exhibited obvious xerophytic characteristics. The variation range of plant diversity in the Western Ordos Steppe Desert was small and remained at a high level. Community similarity in different habitats was low.

Abstract:[Objective] The decomposition characteristics and influencing factors of plant litter for ecological restoration of a coal mining subsidence area were analyzed in order to provide a theoretical basis for restoration in an arid climate. [Methods] An one-year decomposition experiment that included three litter treatments (Salix psammophila; Populus simonii; 1∶5 ratio of S. psammophila∶P. simonii) and two decomposition soils (sandy soil, loess soil) was conducted in a coal mining subsidence area of Inner Mongolia using the field decomposition bag method. The residual dry mass and contents of organic carbon (OC), nitrogen (N), phosphorus (P), acid detergent fiber (ADF), and acid detergent lignin (ADL) of litter samples were determined once every two months. [Results] ① The decomposition rate of S. psammophila litter was significantly (p＜0.05) greater than the decomposition rates of P. simonii and the mixed treatment by 10%~15%. The litter decomposition rates in the loess area were significantly greater than in the sandy area by 13%~23%. ② The litter source had significant (p＜0.01) effects on OC, N, and P contents. Soil type had significant (p＜0.05 or p＜0.01) effects on OC, N, P, ADF, and ADL contents. Both tree species and soil type were important factors affecting the nutrient transformations of the litters. ③ The OC and N contents of S. psammophila litter were greater than those of P. simonii and the mixed litter. P content of P. simonii and the mixed litter were lower than the P content of S. psammophila litter during the first four months, and then the P contents of all of the treatments were similar. [Conclusion] P. simonii litter decomposed more slowly than S. psammophila litter, and therefore, can be maintained for a longer time on the surface of soil. Therefore, P. simonii is recommended to be used as a suitable restoration plant in the coal mining subsidence area of Inner Mongolia.

Abstract:[Objective] In view of the current situation of water eutrophication in water storage ponds in recent years, the pollution characteristics and water quality status of water storage ponds were clarified in order to provide a scientific basis for water purification research and water environmental protection. [Methods] Measurements of pH value, dissolved oxygen (DO), total nitrogen (TN), ammonia nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), total phosphorus (TP), and phosphate radical (PO₄^3--P) in 14 representative water storage ponds in Xianyang City of Shaanxi Province were determined from the perspective of area, depth, water storage status, and main function of water storage ponds. The water quality of water storage ponds was analyzed by a standard index method and a comprehensive pollution index method. [Results] ① The water pollution of the water storage pond in the survey area was related to the serious external pollution caused by the lack of management and protection of the water storage pond, and was related to the agricultural non-point source pollution caused by the agricultural production activities of rural residents. ② The water quality of most water storage ponds was seriously polluted, and did not meet the water standards for agricultural water and general landscape water. Phosphorus nutrients were the main factor which resulted in water pollution. [Conclusion] The water pollution of water storage ponds has the typical characteristics of rural domestic sewage. Treatment methods suitable for the rural environment should be selected according to the characteristics of water pollution.

Abstract:[Objective] The intrinsic relationship between soil physical and chemical properties and bacterial abundance was determined in order to provide a reference for precise control of soil erosion in a Pinus massoniana forest in red soil erosion areas. [Methods] The study was conducted in a P. massoniana forest in the red soil erosion area of Changting County, Fujian Province. Four stratigraphic backgrounds were analyzed to determine their soil physicochemical properties and bacterial community composition and diversity in a P. massoniana forest. Those stratigraphic backgrounds were the middle member of the Zhangping Formation of the Middle Jurassic (J₂Z²), the lower member of the Zhangping Formation of the Middle Jurassic (J₂Z¹), the early Yanshanian intrusive rocks of the Jurassic (γ₅^2(3)c), and the Quaternary Holocene (Q_h). [Results] The overall performance of the soil physical and chemical properties in the Pinus massoniana forest with different stratigraphic backgrounds followed the order of J₂Z¹>J₂Z²>Q_h>γ₅^2(3)c. The soil nutrient content was abundant and deficient in each stratum background. The soil organic matter content of the J₂Z¹ was higher than that of other strata, the background nitrogen content of Q_h was higher than that of other strata, and the background content of phosphorus and potassium was higher in γ₅^2(3)c. The number of soil bacterial operational taxonomic units (OTU) in the four strata backgrounds followed the order of Q_h>J₂Z²>J₂Z¹>γ₅^2(3)c, and accounted for 21.62%, 18.29%, 16.79%, and 12.08%, respectively, of the total number of OTUs. The diversity of the bacterial community followed the order of J₂Z²>Q_h>γ₅^2(3)c>J₂Z². Soil bacterial diversity was positively correlated with soil water content and soil pH value in J₂Z¹ and Q_h. Bacterial diversity in J₂Z² was positively correlated with soil bulk density and total phosphorus content. Bacterial diversity in γ₅^2(3)c was positively correlated with soil potassium content and available nitrogen content, and positively correlated with soil total nitrogen content. [Conclusion] There were certain differences in the soil physical and chemical properties of a P. massoniana forest with different stratigraphic backgrounds in the red soil erosion area. In the process of vegetation restoration, stratigraphic background factors should be considered for regional governance. Bacteria have certain indications for soil properties of different stratigraphic backgrounds.

Abstract:[Objective] Real-time and accurate monitoring of the ecological environment of the Dongzhuang reservoir basin in Shaanxi Province was carried out to provide data and theoretical support for the development and protection of the watershed and urban economic development. [Methods] Landsat remote sensing images in 2000, 2010, and 2020 were selected, and four indexes (humidity, greenness, dryness, and heat) were constructed based on the Google Earth Gngine (GEE) platform. The remote sensing ecological index (RSEI) was calculated by the principal component analysis method, and the ecological environment changes in the Dongzhuang reservoir basin over the past 20 years were monitored and evaluated. The CA-Markov model based on IDRISI software was used to simulate the ecological environment of the Dongzhuang reservoir basin in 2030. [Results] ① During the past 20 years, the ecological environment of the Dongzhuang reservoir basin has been maintained at the same level, and average RSEI increased from 0.499 to 0.500, indicating a slight increase in the ecological environment. ② According to changes in RSEI values, the ecological environment of the Dongzhuang reservoir basin over the past 20 years was relatively complex, and both improvement and deterioration of the ecological environment continued to coexist for a long time. The policy of returning farmland to forest instituted in 1999 in the Weibei region played a positive role in the improvement of the ecological environment, and its effect has begun to be prominent. [Conclusion] The ecological environment of the Dongzhuang reservoir basin has deteriorated mainly in the towns and their surrounding areas, while the improved areas have mainly occurred in the forest and hilly areas. It is still necessary to give more attention to the balance between rapid economic development and ecological environment management.

Abstract:[Objective] The land use changes in the Yellow River basin during the past two decades were analyzed in order to predict land use in 2030, analyze the landscape pattern index, reveal ecological risk status, and assist with landscape protection, restoration, planning, and governance of the Yellow River basin. [Methods] The FLUS model with land use data from 2000, 2010, and 2020 was used combined with social, economic, topographic, and climatic data and other factors to predict the land use status of the area in 2030. A landscape ecological risk index was constructed through the landscape index, and an in-depth analysis was conducted. [Results] ① From 2000 to 2020, the area of cultivated land decreased by 12 150 km², the area of forest land increased by 2 514 km², and the area of construction land increased by 10 620 km². ② The dominant landscapes in the Yellow River basin were grassland and cultivated land, but the dominance gradually decreased, the overall landscape connectivity increased, aggregation decreased, and landscape diversity increased over time, but the overall landscape was still unbalanced. ③ Landscape ecological risks in the work area were dominated by low and lower risks, supplemented by medium risk, accounting for more than 88% of the total area. The ecological risk areas were relatively stable in space and gradually deteriorated over time. ④ By 2030, the growth rate of construction land area will slow down, the area of cultivated land, grassland, and unused land will continue to decrease, and landscape fragmentation will increase. The low and lower ecological risk areas increased by 1.12%, the high risk areas increased by 0.26%, and the rest of the risk areas changed little. [Conclusion] The country’s population growth and the gradual expansion of cities have had a huge impact on land use, resulting in fragmented landscapes. In addition, the environment of the Yellow River basin is fragile, with high sandstorm intensity, high degree of desertification, and increased regional ecological risks. The country needs to give more attention to ecological protection and high-quality development of the region.

Abstract:[Objective] The ecological restoration strategy of sandy land in Gansu Province from a macroscopic perspective was investigated in order to provide a foundation for the construction and optimization of a regional ecological space network. [Methods] By combining the land desertification sensitivity index with ecological networks, nodes in areas with higher sensitivity were selected and optimized by increasing the edges through degree centrality and betweenees centrality analysis. The optimization results were verified by comparing the robustness before and after enhancing the edges. [Results] ① The sensitivity of land desertification in Gansu Province showed a spatial pattern of gradually decreasing from the northwest to the southeast, and the land desertification in the northwest was serious. ② The dense ecological sources and corridors in the southeast part of Gansu Province and the scarcity of sources and corridors in the northwest part indicated that the ecological network in the northwest was poorly connected, and the ecological background needed to be strengthened. ③ The node robustness and connection robustness of the ecological network after edge-enhanced optimization was significantly improved, while the robustness of network edges was slightly but not significantly improved. [Conclusion] The stability of the ecological spatial network in Gansu Province can be improved through the edge-enhanced optimization strategy, and the ecological self-restoration capacity can be enhanced. However, the simulated ecological restoration paths may not be suitably transformed or the actual costs of constructing corridors may be large due to geographical constraints, and circumstances should be considered specifically in light of the actual situation.

Abstract:[Objective] The influence of different connection methods on Benggang susceptibility was studied in order to provide a theoretical basis for the refined spatial prediction of regional Benggang in order to provide scientific supports for reasonable, economical, and efficient disaster prevention and reduction. [Methods] A random forest (RF) model was used to select two different connection methods: the improved frequency ratio (ALSA) and the traditional frequency ratio (FR). Annual average rainfall, annual average rainfall erosivity, soil erodibility, slope length factor, clay content, slope, sand content, and standardized VH channel backscatter coefficient (representing the nature of the surface cover) were used as evaluation indexes of Benggang susceptibility in Yongfeng Township, Xingguo County of Jiangxi Province. [Results] ① The accuracy of the ALSA-RF model was greater than the accuracy of the FR-RF model, and the values of ACC and AUC were 83.89% and 0.893 0, respectively; ② The extremely high and high susceptibility areas in Yongfeng Township were mainly located in the southwest, and this result was in good agreement with the actual situation. [Conclusion] The improved frequency ratio connection method better reflected the distribution law of regional Benggang susceptibility than the traditional frequency ratio method, and provided a reference for similar problems in the field of landslide evaluation.

Abstract:[Objective] The impact of scenic spot expansion on the land use pattern of Guilin City, Guangxi Zhuang Autonomous Region was analyzed in order to provide a theoretical reference for coping with the risks brought by a surge in tourism demand, leading to reasonable urban land planning and scientifically guiding the development of tourism. [Methods] The nuclear density analysis method and the future land use simulation (FLUS) model were used to predict and simulate the land use pattern of Guilin City in 2025 under a conventional scenario and under a scenario with scenic spot expansion. Differences in land use patterns between the two scenarios were analyzed by pixel comparison and by landscape indices. [Results] ① Scenic spot expansion will reduce the reception pressure in tourism hot spots in Guilin City, but it would not be conducive to the urbanization of districts and counties close to the tourism hot spots. ② Scenic spot expansion would be conducive to the development of tourism in “growth poles”, such as Yangshuo and Xing’an County, and the influence of the “growth poles” would also impact most surrounding districts and counties, resulting in a greater expansion of construction land, but a smaller expansion of cultivated land. However, due to the scattered distribution of construction land in the north part of Guilin City, the radiations and driving factors among districts and counties would be relatively limited. Under the scenic spot expansion scenario, more rapid development of tourism in Xing’an, Quanzhou, and Longsheng County had no significant radiation and driving effects on tourism in Ziyuan and Guanyang County, but made these areas less competitive in construction land. ③ The landscape indices showed that scenic spot expansion would lead to more serious disturbance and occupation of agricultural and ecological space such as cultivated land, forest land, grassland, and shrubland. However, scenic spot expansion would promote protection of water bodies and wetlands, and the expansion of construction land would be more integrated. [Conclusion] Scenic spot expansion in Guilin City would reduce the reception pressure in tourism hot spots and promote the development of tourism in “growth poles” and most regions surrounding the “growth poles”. However, scenic spot expansion would not be conducive to the development of areas around tourism hot spots and areas that are relatively remote and not within the radiation ranges.

Abstract:[Objective] The impact of human activity intensity on habitat quality in nature reserves was analyzed in order to provide a basis for improving habitat quality and spatial optimization in nature reserves. [Methods] Based on 2021 land use data and other spatial data, the main land use conflict problems occurring in the He’nan Yellow River wetland national nature reserve, the spatial distribution characteristics of habitat quality, and human activity impacts and their spatial correlations were analyzed using the InVEST model, the human impact index model, and the bivariate spatial autocorrelation model. [Results] ① The main land conflict types in the study areas were rural construction land, farmland, and fish ponds, accounting for 28.85% of the total area. ② The human influence index was above the intermediate level, accounting for 37.97% of the total area; the human influence index was high in the east and west, and low in the middle area. ③ The mean value of the habitat quality index was 0.65, and the area below the medium habitat quality level accounted for 52.46% of the total area, which was generally below the medium level. ④ There was a negative spatial correlation between the human impact index and habitat quality (the Moran’s I was -0.519). [Conclusion] With future integration and optimization, the Yellow River wetland national nature reserve will need to remove farmland and fish ponds, focus protection efforts on river wetlands in the eastern plains, optimize the zone of protection, and develop corresponding control and optimization strategies based on the characteristics of human activities to improve habitat quality.

Abstract:[Objective] The relationship between soil erosion of each formation unit and ecological geological characteristics was analyzed in order to provide a reference for soil erosion prevention and for control planning and restoration in Luoshan County, He’nan Province. [Methods] Based on the revised universal soil loss equation (RUSLE), soil erosion of main formation units in Luoshan County was calculated and counted by means of remote sensing and GIS, and the intensity and the area of soil erosion was determined. The influencing factors of soil erosion in a typical formation were then discussed from the perspectives of geological formation and characteristics. [Results] ① Due to differences in formation times, material compositions, and geological backgrounds, the eco-geological characteristics of each formation unit were different; ② The distribution of soil erosion in Luoshan County had obvious spatial differences. The soil erosion rate of the cretaceous acid magmatic rock formation unit was as high as 50.1%, while the soil erosion rate of the devonian metamorphic flysch formation unit was only 13.5%. [Conclusion] Soil structure, vegetation factors, and terrain slopes were important factors affecting the differences in soil erosion distribution, which should be considered in the planning of soil erosion prevention and rehabilitation.

Abstract:[Objective] The temporal and spatial variation characteristics of water quality in the main stream of the Malian River in the Loess Plateau were analyzed in order to reveal the pollution status and causes of water quality, thereby providing a scientific basis for the construction of ecological civilization and improvement of water quality in the basin. [Methods] Monthly water quality data from 2016 to 2021 for five sections of the mainstream of the Malian River at Qingyang City of Gansu Province in the Loess Plateau were evaluated by using the single factor pollution index method and the comprehensive pollution index method. Trends in water quality evolution were analyzed by using the linear trend method. [Results] ① The overall environmental quality of the Malian River water in Qingyang City from 2016 to 2021 was poor (category Ⅴ), and the comprehensive pollution index was high. The main pollution factors were permanganate index, chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD₅), ammonia nitrogen (NH₃-N), total phosphorus, fluoride and hexavalent chromium. Downstream water quality was better than upstream water quality. ② The seasonal variation characteristics of water quality of the mainstream of the Malian River in Qingyang City were significant. The comprehensive performance was better in summer and autumn than in spring and winter, and the specific performance was best in autumn and worst in winter. [Conclusion] The trend of the water quality of the Malian River in Qingyang City since 2016 has been stable and improved, especially after 2017. Due to the influence of the water quality of the water entering, the river and the geological conditions of the river basin, the water pollution control task for the Malian River still has a long way to go.

Abstract:[Objective] The vegetation cover of the Loess Plateau under different land uses was analyzed in order to provide data support for monitoring the changes of vegetation cover in the region, especially non-photosynthetic (f_NPV) vegetation cover, and provide a reliable basis for the application of remote sensing estimation of vegetation cover in soil erosion prediction. [Methods] Seven vegetation sample plots under different land use types on the Loess Plateau were selected. A stratified vegetation cover survey was carried out at half-month intervals by the sample band method. Then the intra-annual changes of f_PV (photosynthetic vegetation) and f_NPV for different vegetation types and layers were analyzed, thereby providing data support for acquiring vegetation factors for an erosion process model. [Results] ① The total projected cover of the six communities (i.e., sand land, grassland, artificial Caragana korshinskii forest, artificial Pinus tabuliformis. forest, and two natural forests at Huangling and Qinling area) did not vary significantly during the year. Both the projected f_PV and its proportion to total projected cover increased gradually over time and reached maximum values in July to September, and then decreased rapidly after September. However, the projected f_NPV showed the opposite change over time than observed for projected f_PV. The projected f_PV and f_NPV of agricultural land varied dramatically within a year because of the influence of tillage factors. ② During July to September, the proportion of projected f_PV was up to 100% in Huangling and Qinling natural forests, and 60.6%, 70.5%, 58.8%, and 84.9% in the other four species, respectively. This means that only considering the projected f_PV would ignore the ecological benefits of the f_NPV that account for 39.4%, 29.5%, 41.2%, and 15.1% of the total cover. ③ In the vegetation types with obvious vertical structure, such as artificial C. korshinskii forest, P. tabuliformis forest, and the two natural forests in Huangling and Qinling area, the intra-annual changes of f_PV and f_NPV in the tree layer, bush layer, and surface layer were generally consistent with the trend of the projected f_PV and f_NPV, respectively. The projected total cover of the four plots was positively related to the total cover of the surface layer (R² values up to 0.85). [Conclusion] The projection f_PV and f_NPV of agricultural land with different land use in Loess Plateau varied dramatically within the year, while the projection f_PV increased and then decreased in other sample sites within the year, and the projection f_NPV was the opposite of them. The projected f_NPV, which accounted for 15.1% to 41.2% of the projected total cover, was a non-negligible ground cover component in the area. The intra-annual trends of f_PV and f_NPV at different layer were consistent with the projected f_PV and f_NPV, and there was also a significant linear correlation between the total surface cover and the projected total cover. The extraction season of FVC of agricultural land and total surface cover should be focused on during regional monitoring.

Abstract:[Objective] The current situation and influencing factors of water resource vulnerability in Changchun City, Jilin Province were analyzed in order to provide a reference for the development, utilization, protection, and management of water resources in Changchun City. [Methods] The DPSIR model was used to construct a water resource vulnerability evaluation system based on 19 indicators. The entropy weighting method was used to calculate the weights of each indicator. The TOPSIS method was used to evaluate the water resources vulnerability status of Changchun City from 2005 to 2019. [Results] The water resource system of Changchun City was at a mild vulnerability level in 2005, and fluctuated between 0.3 and 0.5 from 2006 to 2019 (a medium vulnerability level). The influence of each sub-system on the comprehensive evaluation results followed the order of pressure (P) > impact (I) > driving force (D) > state (S) > response (R). [Conclusion] Total water use and total water resources are important factors influencing water resource vulnerability in Changchun City, and groundwater has a greater impact on water resource vulnerability than surface water. The government should continue to increase investments in energy conservation and environmental protection, introduce relevant environmental protection policies, improve the treatment of urban water pollution, further optimize the allocation of water resources, promote water-saving irrigation technology, improve the utilization rate of water resources, and alleviate the pressure on water supplies in dry years.

Abstract:[Objective] Water infiltration characteristics at the ridge, furrow, and film hole interface under furrow seeding and sprinkling irrigation on double ridges of inland area of Hexi Corridor at Minqin County, Gansu Province were determined, and the relationship between water transfer and the utilization of agricultural water-saving and farm technology coupling were discussed in order to provide a theoretical basis for the development of efficient agricultural water-saving technologies. [Methods] Four sprinkler irrigation treatments of 24 mm (G₁), 30 mm (G₂), 36 mm (G₃), and 42 mm (G₄) were established in a field experiment, and the HYDRUS-2D model was used to simulate the soil moisture at different positions of the double-ridge and furrow-sowing sprinkler irrigation ridge film hole. Differences and two-dimensional distribution characteristics of soil moisture were determined. [Results] The accuracy of the HYDRUS-2D model to simulate soil moisture for the sprinkler irrigated double-ridge and furrow-sowing system at the film hole was high (average relative error was 6.46%—9.08%, and the coefficient of determination was 0.85—0.95. One day after irrigation, the saturated and humid soil area was mainly concentrated in the 0—30 cm soil layer, and the saturated area of the G₁ treatment was the smallest of all of the treatments due to water deficit. In the 0—20 cm soil layer, the saturated area increased with increasing irrigation amount (i.e., G₂34). However, there was no significant difference in water content between different treatments below the 50 cm soil depth. [Conclusion] Sprinkler irrigation of farmland at the inland arid area of Hexi Corridor mainly affected the upper soil layer. Simulations of soil water distribution by the HYDRUS-2D model were acceptable and the parameters were reliable. The model can be used to formulate sprinkler irrigation system technology for the double-ridge production system.

Abstract:[Objective] The temporal and spatial changes in soil erosion intensity when farmland is returned to forest or grassland in Yan’an City Shaanxi Province were analyzed in order to provide a reference for researches on the planning and evaluation of soil and water conservation, land resource management, and ecological restoration. [Methods] Based on the interpretation results of remote sensing images of Yan’an City from 1990 to 2020 and standards for classification and gradation of soil erosion set by the Ministry of Water Resources, PRC (SL190-2007), soil erosion in Yan’an City was analyzed using the shift-share model. [Results] ① The graded change of soil erosion in Yan’an City as a whole was severe in the north and mild in the south, and the year 2000 was the inflection point where the situation changed from aggravated erosion to gradual recovery. The average soil erosion modulus in Yan’an City decreased from a maximum value of 4 071.38 t/(km²·yr) to 2 366.19 t/(km²·yr). ② The overall change of soil erosion was mainly affected by three erosion levels (slight erosion, moderate erosion, and severe erosion). ③ The shift-share model might be useful in exploring the offset effects of the grain for green project on soil erosion in the districts and counties of Yan’an City. Nevertheless, its application needs to be further investigated and improved due to issues such as accuracy and precision, as well as its ecological significance. [Conclusion] The forest land in the north and central part of Yan’an City increased rapidly, while the grassland in the south increased rapidly. The proportional changes among forest land, cultivated land, and grassland with different coverages were the main reason for the periodic changes in soil erosion.

Abstract:[Objective] The main driving factors affecting the spatio-temporal variation of water conservation on Hainan Island were analyzed in order to provide a decision-making basis for the identification and protection of key areas of water conservation function, water resource management, and regional sustainable development of the Hainan Island ecosystem. [Methods] Based on the water yield module of the InVEST model, the spatio-temporal changes in water conservation on Hainan Island from 1996 to 2020 were quantitatively analyzed, and a geographic detection and analysis of the influencing factors of water conservation on Hainan Island was conducted. [Results] ① The total amount of water conservation in Hainan Island increased slightly from 1996 to 2020. The annual average water conservation was 41.77 mm, and the total water conservation was 1.42 billion m³. Water conservation on Hainan Island was high in the east and north, and low in the west and south. Among all land use types, forest had strong water conservation capacity and accounted for a large area, making a significant contribution to the water conservation of Hainan Island. ② Water conservation had a strong positive spatial correlation, showing obvious aggregation characteristics. The key areas of water conservation were mainly located in the eastern and central parts of Hainan Island, the eastern coastal zone, and the volcanic lava wetlands to the west of Haikou City. ③ The influence of each factor on water conservation followed the order of precipitation>actual evapotranspiration>land use pattern>elevation. The interaction of factors, especially the interaction between precipitation and land use pattern, significantly enhanced the distribution of water conservation. [Conclusion] Climate and human activities dominated the spatial pattern of water conservation on Hainan Island. In the future, it is necessary to fully consider the impact of climate change on water conservation, establish effective measures to ensure that the water conservation function of the Hainan Island ecosystem can effectively adapt to global changes, and ensure land ecological security through rational utilization and management of land resources.

Abstract:[Objective] The change trend of vegetation cover in the Three-River headwaters region, and its ecological environment were analyzed, in order to provide a scientific basis for the macro layout and implementation of ecological construction projects in the future. [Methods] Based on MODIS-NDVI, DEM, and meteorological data, the spatio-temporal evolution characteristics and future development trend of vegetation cover in the Three-River Headwaters region from 2001 to 2020 were comprehensively analyzed from multiple perspectives by using the maximum-value composite procedure (MVC), trend analysis, the Hurst index, and other methods. The responses of climate change and human activities to vegetation cover were analyzed by combining partial correlation analysis and multiple regression residual analysis. [Results] ① The vegetation cover of the Three-River headwaters region has increased significantly over the past 20 years, with a growth rate of 2.1%/10 yr. Overall, vegetation cover was high in the southeast and low in the northwest, and gradually decreased from southeast to northwest. ② Vegetation cover in the Three-River headwaters region increased over time, with the area of increasing vegetation cover accounting for 74.59%, of the total area, and the area of decreasing cover accounting for 25.41%. The vegetation in northeast and northwest areas increased significantly, and the areas in South Qumalai, North Zaduo, and Southwest Gande decreased. ③ The reverse characteristics of future changes in vegetation cover in the Three-River headwaters region were more obvious than those in the same direction. The area of continuous improvement accounted for 29.22% of the total area, and the area of improvement to degradation accounted for 45.54%. ④ Temperature and precipitation had positive impacts on vegetation cover in the Three-River headwaters region, and precipitation was the main driving factor. ⑤ The impact of human activities on vegetation cover in the Three-River headwaters region increased over time, and the positive impact was mainly located in the northeast Yellow River basin, south of the Tongtian River in Yangtze River basin, and the southeast part of the Lancang River basin. [Conclusion] The Three River headwaters region is an important area for ecological security in China. Vegetation coverage is greatly affected by climate and human activities. It will be necessary to strengthen regional ecological protection and ecological maintenance.

Abstract:[Objective] The temporal surface ecological spatial changes and climate-driven characteristics of China’s inland arid grassland at the county scale was determined in order to provide a scientific basis for the formulation of reasonable ecological measures. [Methods] This study was conducted in Sunan County (Yugu Autonomous County of Sunan), Gansu Province. Normalized difference vegetation index (NDVI) and meteorological data were collected and analyzed to determine the characteristics and driving factors of the temporal and spatial changes of vegetation NDVI in Sunan County from 2001 to 2020 using trend analysis, variation analysis, partial correlation analysis, and residual analysis. [Results] ① During the study period, NDVI for the county showed a fluctuating upward trend, with a rising rate of 0.042/10 yr. In addition, the NDVI of the 10 vegetation types showed a similar growth trend that was reflected more accurately than in previous small-scale regional studies. ② NDVI gradually increased from northwest to southeast. The NDVI variation trend was basically stable in 36.14% of the area of Sunan County, while the degraded area was much larger than the improved area. ③ The contribution degree of the different vegetation types to NDVI stability in Sunan County followed the order of coniferous forest>scrublands>broadleaf forest>steppe>meadow>alpine vegetation>cultivated vegetation>others>swamp>desert. ④ NDVI was most affected by summer precipitation and plant growing season temperature. Human activities had a facilitating effect on 96.52% of the vegetation NDVI in Sunan County. [Conclusion] Overall, the vegetation NDVI of Sunan County has increased over the past 20 years, and its change trend was influenced by both climatic conditions and human activities. In the future, vegetation NDVI in the overgrazed areas of Sunan County may continue to decline, but the overall trend will be increasing.

Abstract:[Objective] The changes in water use efficiency (WUE) of the Yellow River basin ecosystem and its sensitivity to different environmental factors were analyzed in order to understand the relationship between vegetation restoration, drought, climate conditions, and water resources, thereby providing a theoretical basis for predicting future land surface-atmosphere interactions and dynamic changes of terrestrial ecosystems. [Methods] We calculated WUE in the Yellow River basin and determined the temporal and spatial dynamics of WUE in different land use cover areas by combining the Theil Sen trend method + Mann Kendall test, the Hurst index, partial correlation analysis, a structural equation model, and linear regression residual analysis in the future. We determined the WUE response to temperature vegetation drought index (TVDI), solar radiation (RS), and wind speed (WIN). [Results] ① The spatial distribution of WUE gradually increased from upstream to midstream, and then to downstream. An overall downward trend was dominant. WUE will continue to be dominated by a weakening trend in the future. ② Upstream WUE was positively correlated with WIN and TVDI. RS had no obvious effect on WUE. TVDI and WIN in the middle reaches had a great negative impact on WUE, and RS was conducive to the improvement of WUE. Downstream WUE was mainly negatively affected by WIN and positively affected by RS, while TVDI had no significant effect on WUE. ③ WUE in grassland and unused land areas was positively correlated with RS, and ncgatively correlated with TVDI and WIN. WUE in other areas was positively correlated with RS and TVDI. ④ Changes in WUE in the upstream region of the Yellow River basin were mainly negatively associated with TVDI and WIN. Changes in WUE in the midstream region were mainly positively associated with RS, TVDI, and WIN. Changes in the downstream region were positively associated with TVDI and negatively associated with RS and WIN. [Conclusion] The WUE of the Yellow River basin will be vulnerable to drought and climate factors in the future. Future studies should further analyze the effects of monthly drought and extreme climate on WUE of different land use areas on the basis of climate factors.

Abstract:[Objective] The response law for runoff under different land use scenarios in the middle and upper reaches of the Weihe River was analyzed in order to provide scientific support for development planning and water resource management of the middle and upper reaches of the Weihe River. [Methods] Based on land use data from 1980 to 2020, the characteristics of land use change in the Weihe River basin over the past 40 years were analyzed. the SWAT model was used to set up five historical land use scenarios, two comprehensive land use scenarios, and three extreme land use scenarios in order to determine the response of runoff under different land use scenarios. [Results] ① During the past 40 years, the areas of cultivated land, water, and unused land gradually decreased, while the areas of forest land, grassland, and residential land gradually increased. ② From 1980 to 2020, the simulated annual average runoff depths were 72.24, 72.27, 72.31, 71.86 mm, and 72.25 mm in five periods, respectively. The average annual runoff depths were 68.59 mm, 69.70, 72.60, 64.81, and 66.82 mm, respectively. [Conclusion] The SWAT model had good adaptability for the middle and upper reaches of the Weihe River. The impact of land use type changes on runoff in the middle and upper reaches of the Weihe River was less than 10%. Returning farmland to forest and grassland was mainly responsible for inhibiting runoff. In the three extreme land use scenarios, runoff size followed the order of cultivated land type＞grassland type＞forest type, and the differences between cultivated land and forestland and grassland were obvious.

Abstract:[Objective] The spatial-temporal variation characteristics and influencing factors of cultivated land value in Jinzhong City, Shanxi Province were analyzed in order to provide a scientific basis for the rational utilization and scientific management of cultivated land resources. [Methods] The value of cultivated land resources in Jinzhong City from 2015 to 2020 was calculated by using the value accounting system for cultivated land resources. The spatial variation characteristics and influencing factors of the overall mean value of cultivated land resources in Jinzhong City were analyzed by hot spot analysis and geographical weighted regression. [Results] ① From 2015 to 2020, the overall average value of cultivated land resources was high in the north and low in the south. The high value area (396.57—490.3) was located in Shouyang County and Yuci District, and the low value area (95.01—101.87) was located in Heshun County and Zuoquan County, with large regional differences. ② The comprehensive value of cultivated land resources in Jinzhong City exhibited spatial agglomeration, with low value areas located in Zuoquan, Heshun, Yushe, and Lingshi County, and high value areas located in Yuci District and Shouyang County. [Conclusion] The factors influencing cultivated land value had obvious spatial heterogeneity characteristics in Jinzhong City. Positive correlations were found with market town impact degree, road accessibility, irrigation guarantee rate, rural road network density, multiple cropping index, and per capita cultivated land area, while a negative correlation was found with topographic position index.

Abstract:[Objective] The spatio-temporal characteristics and aggregation degree of the coupling coordination between rural revitalization and sustainable land use in China from 2010 to 2019 were analyzed in order to provide a basis for promoting the completion of the rural revitalization strategy, improving rural prosperity, and maintaining sustainable land use. [Methods] An index system was constructed based on 31 provinces in China. The coupling degree and coordination degree model and spatial autocorrelation model method were used to analyze the data. [Results] ① The horizontal spatial distribution of rural revitalization and sustainable land use in China decreased from east to west. The regional gap between provinces decreased. ② The coupling coordination values were mainly between 0.6 and 0.7, belonging to primary coordination. The spatial distribution was characterized as being “strong in the east and weak in the west”, and a trend of striping pursuit in the west, central, and east was obvious. ③ Global Moran’s I index was positive (0.484 4~0.566 4), and the local aggregation characteristics were gradually prominent. The distribution was dominated by the high-high aggregation type in the east, and by the low-low aggregation type in the west. [Conclusion] There were significant regional differences in the level of coupling coordination between rural revitalization and sustainable land use in China. In the future, in response to the regional orientation of accelerating the modernization of the eastern part of the country, the revitalization of the northeast, the rise of the central region, and the development of the west, the development and interaction between regions should simultaneously be strengthened, the radiation-driven effect of the eastern region should be increased, and the development level of the western, central, and northeastern regions should be enhanced.

Abstract:[Objective] The spatio-temporal variation pattern and change law of ecological service value (ESV) in the Lijiang River basin during 2000—2020 were determined in order to provide a spatial governance method for optimizing land use structure and achieving the “dual carbon” goal. [Methods] Based on remote sensing information mining and a geographic information analysis platform, ecological service values were evaluated by value accounting and its dynamic and sensitivity analysis methods. The spatio-temporal pattern of ESV was studied by spatial autocorrelation methods. The leading factors and drivers of ESV differentiation were diagnosed by geographic detection methods. [Results] ① The spatial heterogeneity of land use/cover in the Lijiang River basin was significant. The area of forest land and cultivated land was the largest, and change was stable. The area of construction land grew rapidly. ② The ecological service value for the Lijiang River basin was about 3.75×10⁷ yuan. The ESV of forest land and grassland was the highest, accounting for 52.44% of the total value. The overall change initially increased rapidly and then decreased slowly. The value of raw material production and soil and water conservation increased significantly, while the value of food supply and water conservation decreased significantly. ③ In general, ESV showed a pattern of low values in the midstream region and high values in the upstream and downstream regions, exhibiting a positive spatial agglomeration feature. [Conclusion] Urban expansion is the core driving force of the spatio-temporal differentiation of ESV and its dynamic changes in the Lijiang River basin. Disturbance of ESV by human activities is increasing over time.

Abstract:[Objective] Temporal and spatial pattern changes and driving factors of a water conservation function in the Beijing-Tianjin-Hebei region were analyzed in order to provide scientific support for ecological protection and construction in the process of regional coordinated development. [Methods] Using the InVEST model and a water conservation formula with basic geographic data and relevant parameters for the study area, the temporal and spatial pattern change characteristics and main driving factors of a water conservation function in the Beijing-Tianjin-Hebei region from 2000 to 2019 were analyzed. Spatial analysis methods such as univariate linear regression, coefficient of variation, and land use transfer matrix on the ArcGIS platform were also used. [Results] ① The average annual water yield in the Beijing-Tianjin-Hebei area was 1.87×10¹⁰ m³. The spatial pattern of water yield was high in the east and low in the west. ② The spatial pattern of water conservation in the Beijing-Tianjin-Hebei region was higher in the Yanshan and Taihang Mountains (varying from northeast to southwest), and lower in the Bashang Plateau and the Hebei Plain (varying from northwest to southeast). ③ The amount of water conservation varied greatly from year to year, and the annual average amount of water conservation was 7.85×10⁹ m³ (lowest in 2002 and highest in 2012). On the pixel scale, the area of the enhanced area of water conservation function was larger than that of the weakened area from 2000 to 2019. The enhanced area accounting for 67.49% of the study area. The weakened area accounted for 32.51% of the study area. In the past 20 years, the water conservation function could be characterized as being “mainly medium and low fluctuations, with strong fluctuations in a few areas”. The low fluctuation and relatively low fluctuation areas accounted for 93.96% of the total area, and the medium fluctuation, relatively high fluctuation, and high fluctuation areas accounted for 6.04% of the total area. ④ The main driving factors for the change of the water conservation function in the Beijing-Tianjin-Hebei region were precipitation, potential evapotranspiration, and land use changes. The depth of water conservation in typical areas had a significant positive correlation with precipitation, and a significant negative correlation with potential evapotranspiration. With regard to land use changes, ecological projects such as returning farmland to forest and grassland increased the area of forest land and grassland, and relatively increased water conservation capacity. Expansion of industrial and mining construction land encroached on the area of forest, grass, and cultivated land, and water conservation capacity has been relatively reduced. [Conclusion] The temporal and spatial patterns of the water conservation function have noticeable changed in the Beijing-Tianjin-Hebei region. The main driving factors of the water conservation function are meteorological factors and land use changes.

Abstract:[Objective] The comprehensive value of cultivated land in the North China Plain were estimated, and the value differences and change trends were analyzed, in order to provide a scientific basis for the protection of cultivated land in China, and promote the formation of a new pattern of “multiple integrated” cultivated land protection. [Methods] Based on the actual function of cultivated land and the impacts of artificial cultivation, the value of cultivated land was divided into positive values (economic value, social value, and ecological value) and negative values (environmental impacts of pesticides and chemical fertilizers). The comprehensive value of cultivated land in the North China Plain in 2000, 2010, and 2020 was calculated by the income reduction method, the value substitution method, and the equivalent factor method. [Results] The values of cultivated land in the North China Plain in 2000, 2010, and 2020 were 5.01×10¹², 8.45×10¹², and 6.43×10¹² yuan, respectively. The proportion of the economic value of cultivated land showed a downward trend, and the positive value was greater than the negative value during the study period. Moreover, the distribution of the value among provinces was unbalanced, and was greatly affected by cultivated land area, farming methods, and agricultural product prices. The value of cultivated land in Shandong Povince has always been more prominent, while the value of cultivated land in He’nan Province has fluctuated greatly. The negative value of cultivated land per unit area in each province showed an upward trend. [Conclusion] In 2000, 2010, and 2020, relative to the positive value in the North China Plain, the proportion of economic value showed a downward trend, and the importance of the social value and the ecological value of cultivated land gradually became prominent. The negative value per unit of cultivated land in each province showed large regional differences, and the negative value showed an upward trend, especially in He’nan Province. The negative impacts of agricultural film and chemical fertilizer on cultivated land have not been effectively controlled, and the trend is increasing year by year.

Abstract:[Objective] The spatial pattern of a soil fertility index and differences in the main controlling factors for two topographical areas in Hubei Province was determined in order to provide a theoretical basis for soil quality improvement, agroecological environment, and arable land quality enhancement in different topographical areas. [Methods] Data for four soil fertility indicators (soil organic matter, total nitrogen, total phosphorus, and total potassium), along with 13 environmental impact factors 〔land use type, soil-forming parent material, soil type, elevation (DEM), surface relief, slope, normalized difference vegetation index (NDVI), average temperature, average precipitation, roads, industrial and mining sites, urban settlements, and rivers and reservoirs〕, were collected and compiled. Basic statistics, geostatistics, inverse distance weighting, and a geographic detector model were used to analyze the spatial distribution characteristics of each soil fertility index in different topographic areas and to determine the correlation between each soil fertility index and environmental factors. The main controlling factors of the soil fertility index content differentiation in different topographic areas were identified and compared. [Results] The main controlling factors for the soil fertility indexes in Xiangzhou District were precipitation, average temperature, and the distance of road land, urban settlement land, industrial and mining land, and rivers and reservoirs. The main controlling factors for soil fertility indexes in Fang County were precipitation, average temperature, slope, slope direction, surface relief, and the distance of rivers and reservoirs. [Conclusion] The spatial patterns of soil fertility indicators in Xiangzhou District and Fang County differed in their main controlling factors due to topographic factors, and the plain areas were more susceptible to human activities.

Abstract:[Objective] The impacts of soil erosion on the spatial distribution of soil organic carbon (SOC) and total nitrogen (TN) in the sloping farmland of the Southeast Tibet Plateau were determined in order to provide a scientific basis for land resource utilization and soil resource conservation. [Methods] Spatial patterns of soil erosion were investigated using the ¹³⁷Cs tracer method combined with field investigation. Correlations between ¹³⁷Cs inventories and inventories of SOC and TN were determined using correlation analysis. [Results] For the terraced toposequence, discrete patterns of ¹³⁷Cs inventories were found, and an abrupt increase in ¹³⁷Cs inventories was observed between lower slope positions of the upper terrace and the upper slope position of an adjacent lower terrace. A fluctuating increasing trend in ¹³⁷Cs inventories was observed from the upper terrace to the lower terrace. A gradual increasing trend in ¹³⁷Cs inventories appeared within a terrace, indicating that soil loss occurred at the upper slope positions and soil deposition appeared at the lower slope positions. For sloping farmland, increasing and decreasing trends in ¹³⁷Cs inventories appeared along the slope transects, accompanied by decreasing and increasing trends in the soil erosion rate. Low ¹³⁷Cs inventories were observed at the summit and toe slope positions of sloping farmland, and the highest ¹³⁷Cs inventories were found at the middle slope positions. ③ Inventories of SOC and TN showed similar spatial patterns to those observed for ¹³⁷Cs inventories, and a linear relationship was found between¹³⁷Cs inventories and SOC and TN inventories (p＜0.05). [Conclusion] Soil erosion was one of the most important driving forces affecting SOC and TN transport along a slope transect. Overall, the spatial patterns of ¹³⁷Cs can be used to trace spatial patterns of SOC and TN in the sloping farmland of the Southeast Tibet Plateau. The ¹³⁷Cs tracing method was a useful tool to elucidate the redistribution and migration of soil and nutrients on a slope. Furthermore, tillage erosion should be given the same attention as water erosion in order to prevent and control soil erosion in this area.

Abstract:[Objective] The future land use and land cover change (LULCC) and its impact on ecosystem carbon storage were predicted in order to provide a scientific basis for regional land use decision-making and carbon management. [Methods] Based on the quantitative analysis of 30 m resolution remote sensing images of Hainan Island in 1990, 2000, 2010, and 2020, the spatio-temporal evolution of land use and its impact on carbon storage were analyzed. Combined with geographic information system (GIS) spatial superposition analysis, the spatial patterns and mechanisms of land use changes in coastal zones and the impacts of complex land use changes on tropical and subtropical coastal zones were assessed. The InVEST model was used to estimate carbon storage in Hainan Island’s coastal zone. The estimation was further linked to the GeoSOS-FLUS model to predict the distribution characteristics of multi-scenario land use changes in the study area in 2030, and to analyze the influence mechanism on ecosystem carbon storage under different future scenarios. [Results] ① From 1990 to 2020, the areas of cropland, forest land, grassland, and unused land in the study area decreased, while the areas of water and built-up land increased. Among them, the areas of unused land and cropland consistently decreased every year, while the area of built-up land increased year by year. ② Land use/cover change led to a continuous decrease in carbon storage for the study area, reaching 1.50×10⁶ t with a decline rate of 5.00×10⁴ t/a over the past 30 years. The increase in built-up land and the decline in forestland were the key causes for the decrease in carbon storage. The increase in carbon storage due to the transformation from unused land to grassland was the most significant change, with an increase of 1.25×10⁵ t. On the other hand, the change from grassland to forest land (artificial forest land) was the most prominent cause for the decrease in carbon storage, accounting for a decrease of 5.68×10⁵ t. ③ Predicted carbon storage in the Hainan Island coastal zone based on the FLUS model was evaluated. The accuracy met the research requirements verified by historical data. Among the three prediction scenarios, forestland will be effectively protected by 2030 only under the ecological priority scenario with an increase in area of 11.91 km². Built-up land will increase to different degrees under the three scenarios, and the development priority scenario had the largest increase. [Conclusion] A large area of natural grassland with high carbon density on Hainan Island has transformed into artificial forest land with low carbon density, and the high carbon area has transformed into a low carbon area, which weakened the regional carbon sequestration ability. A series of land use regulation policies should be adopted to increase the proportions of woodland, grassland, and other land types, and to optimize the transformation of regional carbon sources into carbon sinks.

Abstract:[Objective] The internal response relationship and mechanism of action among industrial development, carbon emission and land use in the Yangtze River economic belt were studied in order to provide ideas for regional coordinated development. [Methods] Based on the GM(1,1) prediction model, the grey prediction of industrial development, land use, and carbon emission index were determined. A coupling coordination analysis was carried out, and the panel vector autoregression (PVAR) model was applied to determine the response relationship among the three factors. [Results] ① The coupling degree among the regional factors was greater than the coordination degree, and the coupling coordination state showed an increasing trend. The trend within the region decreased from downstream to upstream. ② Land use intensity had a positive impact on industrial development in the first two periods, and industrial development had an inverted V-shaped fluctuation trend in which the impact on carbon emissions was first negative and then positive in the last two periods. Land use had an obvious positive impulse impact on carbon emissions. ③ The three factors mainly depended on their own development paths. However, the explanatory power of industrial development on carbon emission intensity was greater than that of land use intensity, and with the increase of the number of periods, the influence of both on carbon emissions tended to increase. [Conclusion] While industrial restructuring and land use allocation and protection are indispensable in the process of economic development, carbon emissions (as an important constraint in future development) can not be neglected. Determining the response relationships between the three factors can better provide a basis for coordinated regional development.

Abstract:[Objective] The net primary productivity (NPP), carbon fixation, and oxygen release in a wetland of Ezhou City, Hubei Province were estimated, and a method for estimating wetland NPP on small and medium-scale wetlands involving large areas of water was established in order to provide accurate data support for related policies. [Methods] A wetland classification model was constructed to divide Ezhou wetlands into surface wetlands and water wetlands. Remote sensing data and a light energy utilization model were used to estimate NPP for surface wetlands. For water wetlands, chlorophyll a and biomass were introduced as indicators to build a regression model to estimate NPP. The annual total NPP in 2020 was obtained by summarizing the results for both surface wetlands and water wetlands at the same time, and the spatial distribution of NPP, carbon fixation, and oxygen release were obtained. [Results] The annual total NPP was 2.99×10⁵ tons of carbon, the fixation of CO₂ was 4.87×10⁵ tons, and the release of O₂ was 3.59×10⁵ tons. The overall spatial distribution pattern indicated that NPP was high in southern part of the study region and low in the northern part. [Conclusion] A wetland classification model was used to estimate the NPP of water wetlands separately from the NPP of surface wetlands. This method made up for the deficiencies arising from estimating NPP only with a light energy utilization model, and provided estimation results that were closer to observed values for wetlands. This model and method is applicable to similar wetland NPP estimation research involving water bodies.

Abstract:[Objective] The impact of the project to convert farmland to forest and grassland on terrestrial ecosystem carbon storage in the loess hilly-gully region was quantitatively evaluated in order to provide a basis for regional ecological construction. [Methods] The GIS spatial analysis method and the InVEST model were used to study changes in land use and carbon storage in the loess hilly-gully region from 2000 to 2020. [Results] ① From 2000 to 2020, the conversion area of cultivated land to forest and grass land accounted for 20.75% and 86.56%, respectively, of the total conversion amount of cultivated land, and the coverage rate of forest and grassland increased by 1.76%. ② The conversion of farmland to forest significantly improved the carbon storage service in the loess hilly and gully region, and carbon storage increased from 8.22×10⁸ t in 2000 to 8.26×10⁸ t in 2020, and reached a peak of 8.35×10⁸ t in 2010. ③ The increase in net carbon storage of the study area was more than offset the carbon loss, and the contribution rate of carbon storage returning forest and grassland was the largest, which was 38.82% and 22.58%, respectively. [Conclusion] Implementing the project of returning farmland to forest and grassland has had a significant positive effect on the carbon storage of the regional ecosystem. Forest and grassland construction can enhance ecosystem carbon storage services. Future research should focus on the carbon sequestration contribution of ecological restoration projects, the scientific management of forest and grass vegetation, and improving regional ecosystem services.

Abstract:[Objective] The offsetting effects of greenhouse gas (GHG) leakage on carbon sequestration and GHG mitigation in the grain for green project (GGP) were analyzed in order to clarify the difference and spatial pattern of actual GHG sequestration and mitigation contribution of different afforestation types to GHG sequestration and mitigation. [Methods] A method for the GHG budget accounting of different types of afforestation (including ecological forest, economic forest, timber forest, and firewood forest) under GGP (i.e., carbon accounting and net mitigation-GGP) was established. Carbon sequestration effects of afforestation were estimated for selected typical tree species in vegetation and soil. Carbon sequestration of post-logging products and mitigation of fossil fuel substitution by biomass energy were determined. GHG leakage caused by afforestation and management was also determined. The net carbon sequestration of the four afforestation types in GGP in Central South and East China was then evaluated. [Results] The carbon sequestration of ecological forest, economic forest, and timber forest, and the mitigation of firewood forest amounted to a total of 648.43 Tg (CO₂) during the period from 2000 to 2019 in Central South and East China. Additionally, the total GHG leakage of GGP reached 96.43 Tg, which could offset 14.87% of the total carbon sequestration and mitigation. The economic forest produced the largest GHG leakage, which reached 57.69 Tg, offsetting 73.95% of its carbon sequestration. The GHG leakage offset 5.75%, 16.59%, and 27.05% of the carbon sequestration or mitigation effect of ecological forest, timber forest, and firewood forest, respectively. The average net carbon sequestration per unit area of GGP in this region was 4.52 t/(ha·yr) (CO₂), ranging from 2.85 t/(ha·yr) in Guangxi to 5.74 t/(ha·yr) in Anhui. The net mitigation rate of GGP was 5.52~8.89 t/(ha·yr) for ecological forest, 0.72~1.56 t/(ha·yr) for economic forest, 0.8~1.61 t/(ha·yr) for timber forest, and 3.18~5.99 t/ha/yr for firewood forest. [Conclusion] GGP in Central South and East China has achieved huge net carbon sequestration and emission mitigation benefits. Ecological forest had an obvious effect on carbon sequestration, and the net mitigation benefit was the most significant. Biomass energy could replace fossil fuel combustion and its mitigation benefit was also very considerable. The influence of fertilizer-related GHG leakage on ecological engineering carbon sequestration cannot be ignored. Fertilizer-related GHG emissions and their offsetting effect on carbon sequestration in the ecological project were nonnegligible because it was the largest GHG emission factor.

Abstract:[Objective] The evolution characteristics and coupling coordination relationship between the spatial scale of cities, and the spatiotemporal pattern of the carbon budget in urban agglomeration areas were analyzed, and a regional evaluation system for carbon compensation was constructed in order to provide a reference for implementing strategies at the urban agglomeration level to achieve the goal of carbon neutrality. [Methods] Based on an analysis of the spatial and temporal variation of land use carbon income and expenditure and the coupling coordination degree in the Beibu Gulf urban agglomeration area in 2000, 2010, and 2020, the entropy weight method and TOPSIS method were combined to measure the carbon compensation closeness of 15 cities in 2020 in order to construct a comprehensive evaluation system of carbon compensation and to introduce a three-dimensional magic square unit model to initially construct carbon compensation levels for functional zoning research. [Results] ① From 2000 to 2020, the carbon balance of the Beibu Gulf urban agglomeration showed an overall increase, the main carbon emission area at the municipal scale showed a “core-periphery” structure, and the main absorption area has shown a “barb” spatial pattern. ② From 2000 to 2020, the carbon sources and sinks in the Beibu Gulf urban agglomeration area showed a northwest-southeast direction, except for the Guangxi region that showed a northeast-southwest dominant direction, with a stable spatial distribution center of gravity. ③ From 2000 to 2020, the coordinates of carbon sources and carbon sinks in the urban agglomeration area were greater than 0.5. Furthermore, the level of carbon emission and carbon absorption were high, showing relatively high coupling coordination. [Conclusion] There was obvious spatio-temporal heterogeneity in the carbon budget of the Beibu Gulf urban agglomeration, and the degree of coupling coordination between carbon emissions and carbon absorption were high. In order to further explore diversified paths to achieve the “double carbon” goal, regional resource capacity, carbon emission intensity, and economic development conditions should be considered in the future so that the inter-regional carbon compensation system of urban agglomeration areas can be improved.

Abstract:[Objective] The effects of different stand types on soil carbon pools and soil carbon stability in the Geqiugou watershed in Ordos City of Inner Mongolia Autonomous Region were analyzed in order to provide a theoretical basis for determining the mechanism of soil carbon sequestration, optimizing soil management and plant breeding measures in the Geqiugou watershed, and realizing soil carbon sequestration emission reduction and fertility improvement in the Geqiugou watershed. [Methods] Eight-year-old plantations of Pinus sylvestris, Carga cathayensis, Pinus tabulaeformis, Poplar-Caragana mixed forest, Chinese pine and arborvitae mixed forest, sea buckthorn and mountain apricot mixed forest, and a control (CK) treatment were used as the research objects in the Geqiugou watershed from 2013 to 2021. The contents of total organic carbon (TOC), resistant organic carbon (ROC), easily oxidizable organic carbon (EOC), microbial biomass carbon (MBC), and soil carbon storage in different stand types at different soil depths were determined to study the effects of plantations on soil carbon pools, and to determine the relationship between different stand types and soil carbon stability. [Results] Compared with the CK treatment, the contents of TOC, ROC, EOC, MBC, and soil carbon storage in the 0—20 cm and 20—40 cm soil layers increased by 9.46%—51.24%, 1.76%—44.89%, 16.48%—44.26%, 9.03%—64.84%, and 10.61%—55.52%, respectively. [Conclusion] Plantations of different stand types can increase soil TOC, ROC, EOC, MBC contents and soil carbon storage in the 0—20 cm and 20—40 cm soil layers. The soil TOC, EOC, MBC contents and soil carbon storage decreased with increasing soil depth, and soil ROC content increased with soil layers. The soil carbon pool index for each stand type in the 0—20 cm and 20—40 cm soil layers was greater than that of the CK treatment. P. sylvestris, C. cathayensis, and mixed sea buckthorn and mountain apricot were more conducive to soil carbon sequestration in the Geqiugou watershed.

Abstract:[Objective] The effects of applying biochar combined with subsoiling on soil bulk density, soil structure stability, and organic carbon in farmland topsoil were comprehensively analyzed to provide scientific and reasonable control measures and a theoretical basis for soil structure improvement. [Methods] A field experiment was conducted from 2017 to 2019 based on a winter wheat and summer corn rotation system. Biochar was applied at rates of 0, 3 000, and 6 000 kg/hm² (B₀, B₁, and B₂) during the wheat season in conjunction with two tillage treatments 〔traditional stubble sowing (P) and subsoiling tillage sowing (S)〕 imposed during the corn season to produce a total of six combined treatments of B₀P, B₁P, B₂P, B₀S, B₁S, and B₂S. [Results] ① After two crop rotations, under the same tillage method, soil bulk density decreased with increasing biochar application rate, and bulk density under B₂S was significantly lower than under B₀S by 13.59%. Under the same biochar application level, soil bulk density under subsoiling was less than under traditional stubble sowing, and the subsoiling bulk density was 4.95% lower than the bulk density under traditional stubble sowing; ② After two years of continuous application of biochar combined with subsoiling tillage, the organic carbon content of B₂S was the highest, and was 42.15% greater than observed for B₀P and 1.03% greater than observed for B₂P; ③ After two crop rotations, the mechanical aggregate content (DR_0.25), the water-stable aggregate content (WR_0.25), and the mean weight diameter (MWD) showed an upward trend with increasing biochar application rate. In contrast, soil aggregate destruction rate (PAD) and soil unstable aggregate index (ELT) showed a decreasing trend, and B₂S produced better results than the other treatments, indicating that high biochar application rates combined with subsoiling tillage more effectively improved aggregate stability than traditional tillage. [Conclusion] A basic application of 6 000 kg/hm² of biochar during the wheat season combined with corn season subsoiling could improve the stability of soil aggregates and the soil structure of farmland in the North China Plain.

Abstract:[Objective] The spatio-temporal changes and influencing factors of carbon emission at the county scale in Shaanxi Province from 2000 to 2020 were analyzed in order to provide a reference for ecological civilization construction and low-carbon sustainable development in Shaanxi Province. [Methods] Socioeconomic and land use data were used to construct a carbon emission estimation model. The total carbon emission in Shaanxi Province was calculated and the spatiotemporal patterns and changes from 2000 to 2020 were analyzed. Subsequently. The influencing factors of carbon emissions were determined using the geographically weighted regression method. [Results] ① Total carbon emissions increased from 3.30×10⁷ tons in 2000 to 1.93×10⁸ tons in 2020. The evolution of carbon emission can be divided into two stages (substantial growth and slow growth). ② The carbon emission center gradually moved to the northeast from 2000 to 2020, and the spatial distribution range showed an expansion trend. The hot spots were mainly located in the northern counties of Yulin City, and around Xi’an and Xianyang City. The cold spots were mainly located in Foping County and Shiquan County. ③ Per capita GDP, land use degree, and per capita total social retail sales were positively correlated with carbon emissions, while industrial structure and population density were negatively correlated in 60.74% and 92.52% of counties, respectively. [Conclusion] Low-carbon development should be promoted in Shaanxi Province by formulating differentiated regional carbon emission reduction plans, optimizing the land use structure, controlling the expansion of construction land, and by enhancing public awareness of low-carbon environmental protection.

Abstract:[Objective] The effects of different forms of iron and aluminum oxides on soil organic carbon content in native coniferous and broadleaf plantations in south subtropical region of China were studied in order to provide a scientific basis for further understanding the soil organic carbon accumulation mechanism of native tree plantations in this region. [Methods] The study was conducted in three native coniferous and broadleaf planted forests including a pure Pinus massoniana coniferous plantation, a pure Erythrophleum fordii broadleaf plantation, and a mixed plantation of these species located at the Experimental Center of Tropical Forestry, the Chinese Academy of Forestry, at Pingxiang City, Guangxi Autonomous Region. ICP-OES and the potassium dichromate method were respectively used to measure the content of iron and aluminum oxides and soil organic carbon content in different soil layers (0—20, 20—40, 40—60 cm) under each plantation. Analysis of variance was used to determine differences in observed indicators in different soil layers and stands. Pearson correlation analysis was used to test the relationship between different forms of iron and aluminum oxides and organic carbon. [Results] The content of soil organic carbon in the mixed plantation of P. massoniana and E. fordii was significantly greater than in the pure P. massoniana plantation and the pure E. fordii plantation, and the content of soil organic carbon decreased with increasing soil depth in the three plantations. Fe_d (total free mineral Fe oxides) was the highest of all forms of iron and aluminum oxides in the studied stands, followed by Al_d (total free mineral Al oxides), Fe_o (non-crystalline mineral Fe oxides), Al_o (non-crystalline mineral Al oxides), Fe_p (organic bounded mineral Fe oxides), and Al_p (organic bounded mineral Al oxides). Furthermore, Fe_d and soil organic carbon had a significant negative correlation (p＜0.05), while Fe_o, Fe_p, and Al_p were positively and significantly correlated with soil organic carbon content (p＜0.05). [Conclusion] Soil organic carbon mineralization was enhanced due to high levels of Fe_d under native coniferous and broadleaf plantations in south subtropical region of China. Although Fe_o, Fe_p, and Al_p contents were low, they could increase soil organic carbon retention and stability.

Abstract:[Objective] The accounting targets for carbon sequestration in ecological restoration were clarified in order to provide a scientific basis for further formulating policies and measures for carbon sequestration and carrying out relevant research to achieve carbon neutrality as scheduled. [Methods] The meaning and function of carbon sequestration in ecological restoration were reviewed. The mechanisms and approaches of carbon sequestration in ecological restoration were introduced. The effects of different measures on carbon sequestration in ecological restoration were analyzed. Potential methods and countermeasures for carbon sequestration in ecological restoration were proposed. [Results] The three main pathways for ecological restoration include forest and grass, soil, and wetlands. The carbon sequestration effect is remarkable, and carbon sequestration potential is huge, long-term, and sustainable. [Conclusion] In order to achieve a greater degree of carbon sequestration, it is necessary to seek new breakthroughs in the field of ecological restoration, promote improvement in ecosystem quality and efficiency, comprehensively strengthen resource protection, continue to tap the potential of ecological carbon sequestration growth, and further promote ecological restoration and governmental engineering and construction projects.