Monitoring of forest disturbance in "Three Mountains" of Ningxia based on GEE and LandTrendr
[Background] The natural reserve of Liupan Mountain, Luo Mountain, and Helan Mountain in Ningxia (Abbreviated as "Three Mountains") is an important ecological security barrier in Northwest China. Studying on whether there are obvious differences between the degree and tendency of forest disturbance in "Three Mountains" or not, and the main reasons causing forest disturbance has great reference value in protecting the natural reserve of "Three Mountains", the Northwest region, even the ecological safety in The Yellow River basin. [Methods] Based on the Landsat 5-8 time series stack (1990-2020) in the GEE (Google Earth Engine) remote sensing cloud platform, the forest disturbance in the "Three Mountains" of Ningxia over the past 30 years was monitored by the LandTrendr time series segmentation algorithm, and the accuracy of the monitoring results was evaluated with the help of Google images, and the spatial and temporal distribution characteristics of the forest disturbance were statistically analyzed. [Results] 1)The user accuracy, producer accuracy and overall accuracy of LandTrendr algorithm were all >90%, Kappa coefficient reached 0.87, and there was no significant difference between the result of LandTrendr algorithm and manual visual inspection (McNemar's test>0.05). 2)The overall forest disturbance area ratio of "Three Mountains" in 1991-2020: Liupan (1.77%)>Luoshan (0.07%)>Helan (0.05%). The annual disturbance area ratio of the "Three Mountains" tended to decrease, and Liupan (52.60×10-4%/a)>Helan (1.58×10-4%/a)>Luoshan (0.40×10-4%/a). 3)The forest disturbance of "Three Mountains" mainly occurred in the northern part of Liupan Mountain and 2 exclaves to the east, "Daluo Mountain" in the northern part of Luo Mountain and the center of Helan Mountain. The duration of forest disturbance was 1-3 years, and mostly within a year. [Conclusions] Among the "Three Mountains", the disturbance level of Liupan Mountain is much higher than that of Luo and Helan Mountain, but the disturbance area of the "Three Mountains" is decreasing year by year, with the most obvious decrease in Liupan Mountain followed by Helan Mountain and Luo Mountain. The disturbance in Liupan and Luo Mountain is mainly caused by human activities, but in Helan Mountain, it is caused by both human activities and natural conditions.
Analysis of the dynamic monitoring results for soil and water conservation during 2012-2016 in Yunnan province
[Background] Yunnan province is a mountainous area, with as much as 94% of the total area belonging to this category. There are many high mountains and valleys, complex and diverse climate types, numerous rivers and lakes all in tandem with heavy and concentrated rainfall. Moreover, with the continued impact of human activities, soil erosion has become very serious in Yunnan. Serious soil erosion has caused the decline of land productivity, siltation of riverbed and water bodies, and natural disasters such as frequent floods, drought and debris flow. Controlling soil erosion and improving the ecological environment is an important task for the ongoing ecological construction in Yunnan province. [Methods] Based on the monitoring compilation data of soil and water conservation monitoring sites in Yunnan province from 2012 to 2016, 36 soil and water conservation monitoring sites were positioned and divided into soil and water conservation type areas according to the national 3-level division of soil and water conservation. The dynamic monitoring of soil and water loss in the Yunnan province was studied in depth from the aspects of rainfall, runoff and sediment production in runoff field of different land use types and small watershed, non-point source pollution output in runoff field and small watershed, debris flow monitoring. [Results] The runoff rates of different soil and water conservation type areas showed as wasteland>sloping farmland>grassland>terrace>garden>forest. The soil erosion moduli were in the order of sloping farmland>wasteland>terrace>garden>grassland>forest. Average annual watershed runoff moduli of different soil and water conservation type areas were 0.12-12.05L/(s·km2), and the sediment modulus was 6.20-1659.00t/(km2·a). The average annual runoff moduli of representative hydrological sites were 0.20-10.90L/(s·km2), and the sediment moduli were 1.28-686.00t/(km2·a). After constructed contour reverse-slope terrace in sloping farmland, the loss of N steadily reduced 62.78%-86.50%, and the loss of P steadily reduced 50.41%-90.83%. The outputs of total nitrogen concentration and total phosphorus concentration were 2.55-5.23mg/L and 0.65-1.36mg/L respectively in the Yizhe small watershed from 2012 to 2016, and the outputs of N amount and P amount were 3.65-15.12t and 0.95-2.44t. Short duration torrential rain was one of the important causes leading to debris flow. It was easy to cause secondary debris flow if strong rainfall occurred in a short period after debris flow occurred. [Conclusions] This study reflected the basic situation of soil and water loss in Yunnan province, which can provided a basis and reference for the monitoring work of soil and water conservation monitoring sites in the future, and provide a theoretical basis and data support for the prevention and control of soil and water loss.
Mechanical characteristics of herbaceous roots and soil anti-scourability on the slope of dump yards
[Background] Many dump yards are formed during backfilling earthwork. The soils were loose and soil nutrient was deficient in dump yards. Vegetation are widely used to reinforceside slope of dump yards. At present, the researches on soil fixation of side slope were mainly concentrated on highway slopes and reservoir slopes. Few reports were concentrated on side slope of stone dump yards. [Methods] Compared with bare land of dump yards in Diexi town of Mao county, native herbs (Taraxacum mongolicum, Phragmites australis, Chenopodium album) and artificially planted herbs (Lolium perenne and Eleusine indica) were as the research objects.In order to screen out herbaceous plants with better performance in soil conservation and slope fixation,electronic universal testing machine, direct shear apparatus and soil anti-scourability experimental device were applied to measure the maximum tension resistance and tensile strength of single root, the shear strength of root-soil composite and soil anti-scourability index, respectively. [Results] 1)The tensile resistance of herb roots increased with the increase of root diameter, whereas the tensile strength decreased with the increase of root diameter. The average root tensile resistance of five herbs presented as C.album (12.42N)> T.mongolicum (11.52N)> P.australis (7.96N)> E.indica (4.36N)> L.perenne (3.36N), while the tensile strength showed an opposite trend as L.perenne(62.6MPa) >E.indica(43.8MPa)>P.australis(43.7MPa)>T.mongolicum(32.2MPa)>C.album(27.2MPa). 2)The root-soil composite of L.perenne generally showed the highest shear strength, followed by E.indica, C.album, T.mongolicum, P.australis and bare land under 4 load conditions (level 50, 100, 150 and 200kPa). 3) Soil anti-scourability indexes of five herbs presented as L.perenne(3.09min/g)> C.album (2.93min/g)> E.indica (2.60min/g)> T.mongolicum (2.19min/g)> P.australis (1.52min/g)> Bare land (1.37min/g).[Conclusions] C.album showed maximum tension resistance of single root, and the L.perenne showed maximum anti-scourability and shear strength. Therefore, C.album and L.perenne should be considered invegetation restoration of dump yards in the barrier area of western Sichuan basin.
Performance test and stability analysis of jute planting bag on subgrade slope
[Background] In the process of engineering construction, soil erosion often occurs, which affects the stability of the slope. Soil and water conservation slope protection project is important for restoring and building a good ecological environment. The plant bag made of natural jute has outstanding environmental protection and economy. The jute fiber can provide nutrients for plants after decomposition. There are few studies on the stability analysis of the bag itself, and the planting bag itself is more prone to be damaged under heavy rainfall. Therefore, the stability analysis is crucial. [Methods] In order to explore the basic physical and mechanical properties of jute planting bag and its stability in practical engineering, the physical and mechanical properties of density, tension and tear of common jute cloth materials for planting bag were tested. Based on the basic assumptions, the stabilities of jute planting bags under natural conditions and heavy rainfall conditions were calculated according to the force balance method and the conditions of subgrade slope, and the evaluation method of bag stability was proposed by calculating the stability coefficient. [Results] 1) The average tensile strength of the two types of jute cloth were 14.7kN/m and 22.2kN/m, the average elongation at break were 6.1% and 10.7%, and the average tearing strength were 0.35kN/m and 0.56kN/m, respectively. The basic performance met the performance requirements of national standards for planting bags. 2) Under the condition of force equilibrium, the stability coefficient of jute planting bags under natural conditions was 1.51, thus the stability of jute planting bags on the subgrade slope was good. The stability coefficient was 0.52 under the saturated condition of heavy rainfall, which was insufficient. 3) The jute planting bags were reinforced by anchor mesh. The pull-out safety coefficient of the anchor was 1.58, therefore the jute planting bags were of good stability. [Conclusions] The basic performance of jute cloth meets the performance requirements of national standards for planting bags. Under the saturated condition of heavy rainfall, the stability of jute planting bag is insufficient, and reinforcement methods should be adopted. Based on the pullout stability of anchor rod, the stability evaluation method of jute planting bags reinforced by anchor mesh is established. Combined with examples, it is proved that anchor mesh is very effective to enhance the stability of jute planting bags on subgrade slope.
LI Wenlong, YUAN Li, WEI Wenjie, LIU Zhuohao, GAO Ruiyu, NIU Yong, ZHAO Chuanpu, ZHANG Ronghua
Effects of two spatial data structures on soil erosion assessment at county scale
[Background] The existing county-scale soil erosion evaluation method mostly uses raster structure as the basic calculation unit, leading to multiple raster numbers and multiple erosion intensities in a single vector plot, which makes it difficult to directly apply to vector plot-based soil erosion control and planning. Therefore, studying the impact of different spatial data structures of raster and vector on soil erosion calculation and evaluation is of great significance to the dynamic monitoring of soil erosion and the application of results, and to serve soil and water conservation planning and soil erosion control. [Methods] This study used Ruzhou city, Henan province as the research area, based on two different spatial data structures of raster and vector, combined with China's soil loss equation and remote sensing monitoring, the differences in soil erosion among 5 methods were compared and analyzed. [Results] 1) The raster statistics method based on raster calculation took 8min, which quickly and accurately calculated the soil erosion area and intensity, and accurately described the erosion area and intensity of different land uses, but the mapping effect of aggregation index was bad. This method was suitable for soil erosion evaluation at county scale that did not require mapping. 2)The software judgment method presented the smallest difference in calculation results, and demonstrated the best effect in drawing. Compared with the raster statistics method, the software judgment method had a difference of 0.05km2 in the erosion area, with a difference rate of 0.01%, and it had a small difference in the erosion area of different erosion intensity and different land use, which took 13min. The aggregation index was 96.81%, which was good mapping effect. It is suitable for soil erosion evaluation and mapping at county level. 3)The calculation time of the land parcel evaluation method was moderate, which was 16min. But the erosion area difference was 64.63km2, the difference rate was 16.02% and the area of different erosion intensity cannot be provided. It was not suitable for soil erosion evaluation at the county scale. 4) There were large differences in soil erosion area, intensity and erosion area of different land use between two vector calculation methods. The large amount of vector data led to longer calculation time, but the advantage was that the mapping effect was better. These two methods were suitable for calculation and evaluation of soil erosion in plain areas with relatively consistent soil types, terrain slopes, and vegetation coverage. [Conclusions] The research results may provide reference for water erosion evaluation, dynamic monitoring of soil and water loss and application of the results at county level.
Effects of six shrub species in semi-humid region on the rainfall interceptions
[Background] With the increasing cost of urban water resource, how to develop a water-saving planting mode in urban greenland and transform water consuming mode into water saving mode have become an academic hotspot which needs to be urgently solved for urban greenland management in semi-humid region. [Methods] Using an artificial simulated rainfall system, we selected Chengyang district of Qingdao as an experimental area, determined the canopy interception of 6 shrub species including Ligustrum×vicaryi, Euonymus japonicus, Buxus sinica var. parvifolia, Photinia×fraseri, Juniperus chinensis and Platycladus orientalis, and analyzed the relationships between morphological characteristics and canopy interception. [Results] Among 6 shrub species, the leaf area, leaf width and leaf length/width ratio of J.chinensis and P.orientalis were remarkably different with the other 4 shrub species and the LAIs of J.chinensis and P.orientalis were significantly higher than those of the other 4 shrub species (P<0.05). For all the 6 shrub species, the descending order was throughfall rates>interception rates>stemflow rates, and throughfall and stemflow increased significantly, while the canopy interception decreased with the increase of rainfall intensity. Throughfall rates of broad-leaved shrubs were higher than that of coniferous shrubs (P<0.05), and the changing trend of stemflow rates was similar (P<0.05). However, the canopy interception rates showed an opposite pattern (P<0.05). LAI, leaf width, leaf length/width ratio and contact angle were significantly correlated with canopy interception (P<0.05), and LAI, phylliform and leaf wettability were the most important factors affecting canopy interception of shrubs. [Conclusions] The broad-leaved shrubs tend to form a "funnel-shaped" stemflow water accumulation system, which contributed to the storage of soil water, while the coniferous shrubs favor canopy interception due to higher LAI, special leaf shape and high wettability of leaf surface, and had a stronger ability to regulate the storm flood before the canopy is water-saturated.
LI Qingfeng, GUO Xiaoping, WAN Yajun, XUE Xinyue, SU Ruidong
Evaluation on the ecological restoration engineering modes of waste dump in the coal mine of desert area
[Background] Extensive mining in the Northwest arid desert area has caused serious ecological environment destruction. The ecological restoration of waste dump is very difficult. At present, the ecological restoration modes of waste dump restoration engineering is single and the matching measures are incomplete. Besides there is a shortage of ecological restoration modes which are suitable for the application of different site types in the Northwest arid desert area with well restoration effect. The purpose of this study is to systematically evaluate ecological restoration modes and pick out suitable ecological restoration modes for different site types. Besides we will make suggestions for each mode based on soil carbon storage; soil total nitrogen storage and C/N. [Methods] We investigated the vegetation growth status and soil physical and chemical properties of 14 restored waste dumps in Wuhai city. We selected 13 indices from vegetation restoration, soil modification and economic cost to construct evaluation system by the combination of component analysis and entropy weight. The evaluation system was then used to screen suitable ecological restoration modes. [Results] 1)The ecological restoration modes that are suitable for different site types consisted of interception and drainage measures and slope protection measures,i.e., gravel capping, Salix pammophila checkerboard, blanket covering, brick square/arch sash, dense mesh covering, ecological bag interception and drainage, dry masonry interception ditch, pipe drainage, and sowing. 2) Blanket covering+ecological bag drainage+sowing mode was suitable for both of medium layer steep shady-sunny slopes; medium layer turned-sharply shady-sunny slopes and medium layer steep shady slopes. 3) The recovery effect of the brick square/arch sash was slightly different, resulting from the difference of layout size and construction quality. [Conculsions] 1)The shady slope is more conducive to vegetation restoration, resulting from lower vegetation transpiration and less soil water consumption. 2) Compared with blanket covering mode, brick square/arch sash mode is more beneficial to organic carbon and nitrogen accumulation in the soil and reduce soil erosion. We screened 14 suitable ecological restoration modes for 9 site types from 23 modes which we investigated in the 14 waste dumps.
DONG Lei, GUAN Chenbo, CHU Dongtao, ZHANG Nian, WANG Chenyi
Preparation of water-retaining coated slow-release urea and fertilizer release characteristics
[Background] The low utilization rate of traditional urea fertilizer has caused serious waste of agricultural resources and non-point source pollution, and the shortage of water resources has also become one of the important factors restricting the development of agriculture in China. Therefore, water-retaining coated slow-release (WRCU) urea has become the inevitable trend of optimal application of soil nutrient resources and development of water-saving agriculture. However, the cost of the existing WRCU is too high, which limits its application in agriculture. [Methods] A novel WRCU fertilizer was developed by using the transfer drum coating technique with large particle urea as the inner core carrier, blend (attapulgite∶fly ash=8∶2) as the inner layer, polyacrylic acid resin as the middle layer, and high water absorption resin as the outer layer, to explore the optimal composition ratio of WRCU. The nutrient release rate of WRCU was measured by the Kjeldahl method. Compressive strength of WRCU was measured by universal testing machine. The water retention properties of WRCU were determined by mass difference before and after water absorption from WRCU. Finally, a soil column drenching experiment was used to show the nutrient release characteristics of WRCU in soil media. [Results] The optimal weight ratio of each component in WRCU is: 20% inorganic material (attapulgite∶fly ash=8∶2), 11% polyacrylic acid resin coating amount, 3% superabsorbent resin, the rest is large granule urea. At the same time, the compressive strength of WRCU is 81.59N, the maximum water absorption ratio is 641g/g, total nitrogen dissolution in soil column at 1 day was 12.25%, and the nutrient leaching of total nitrogen and urea nitrogen in 30 day was 81.27% and 47.62%, respectively; while the nutrient leaching of total nitrogen and urea nitrogen by uncoated macroparticles urea within 1d has reached 86.38% and 83.26%. [Conculsions] The WRCU showed good slow-release effect of nutrients and water retention function, and the materials used were easily degradable materials and inexpensive, which made the promotion of WRCU in agriculture possible.
JIN Pingwei, HUANG Jun, JIANG Xuebing, KANG Qing, YANG Shengquan, LIN Liping, YANG Ping, LUO Zhicheng, LI Le, KOU Xinyue, LIU Bin
Automatic recognition and classification of construction projects' disturbed patches based on deep learning
[Background] The supervision and management of soil erosion caused by construction projects is an important legal responsibility and social management function of the water administrative department. Satellite remote sensing imagery is an important method. As the basic data of supervision and management work, the disturbance patch boundary data of construction projects is currently mainly obtained by manual visual interpretation, which has low work efficiency and large cost investment. [Methods] Based on the deep learning principle, a convolutional neural network was constructed to realize automatic identification of disturbance zone, so as to achieve the goal of automatic production of disturbance patch boundary data of construction projects. The remote sensing image of China's high-resolution No. 1 satellite with a resolution of 2 meters was used in this study. The constructed convolutional neural network contained 13 convolutional layers, 5 max-pooling layers, 1 global average pooling layer, 3 fully connected layers and 2 dropout layers. The activation functions in the middle and classification layer were RELU and Softmax, respectively. The training and testing samples were 5131 and 22923, and the proportion of positive samples in the training and testing sample sets were 15.38% and 4.69%, respectively. [Results] The results showed that the optimizer, learning rate and batch size have a significant impact on the model training accuracy. The optimizer and learning rate have a negligible impact on the training time, and the batch size has a significant impact on it. In this study, the Adagrad optimizer, a 10-4 learning rate, and a 16 batch size were the optimal choices to obtain the best trained model with accuracy and loss of 0.9526 and 0.1670, respectively. The testing sample is used to validate the model, and the results showed, the average overall accuracy of the model is 97.52%, the average precision and recall of positive samples (classified samples of interest) are 72.44% and 83.90%, respectively, and the average F1 score is 77.73%. In general, the model recognition and classification results are basically consistent with the actual situation. [Conclusions] This study provides a new method for the production of disturbance patch boundary data of construction projects, which greatly improves work efficiency, reduces input costs, and enhances the efficiency of soil and water conservation supervision and management. In the follow-up, the production of model training sample data should be strengthened, and the model parameters should be further revised to improve the accuracy of model application.
ZHOU Lingfeng, CHEN Suyi, DAI Jinjun, LIU Jundong, XU Lizhen, TIAN Zhujun, ZHAN Zhaohui, ZHAO Wendi, CHEN Jinhui, TU Zhihua
Hydrological effects of litters and soil of seven Magnoliaceae ornamental plants
[Background] Magnoliaceae plants resources is rich in China, which have widely been used in making landscape to demonstrate gardens and cultural connotation by making full use of its aesthetic functions such as posture, culture and good views, and which was introduced in Hainan Tianxiang Magnolia Plant Conservation Research Center in Danzhou county of Hainan province, but lack of understanding the ecological service functions such as soil and water conservation of Magnoliaceae plants in this region. It is of great significance for rational introduction based on the water-holding capacity of each Magnoliaceae plants to render the Magnoliaceae plants configuration more reasonable in garden application. [Methods] Seven common Magnoliaceae plants (Michelia shiluensis, Michelia crassipes, Michelia foveolata, Michelia maudiae, Michelia odora, Manglietiastrum sinicum, Manglietia lucida) in Hainan were selected as the research objects, and the water-holding function of litter layer and soil layer of different Magnoliaceae plants were determined by quantitatively research with immersion method and cutting-ring method. [Results] 1) The litter volume of the seven plants was about 5.24-25.11t/hm2, which followed the order of M.shiluensis>M.crassipes>M.foveolata>M.sinicum>M.maudiae>M.odora>M.lucida. The decomposition degree of dead branches and leaves of Manglietia lucida was high. 2) The maximum water-holding capacity of litter layer varied from 14.32 to 25.45t/hm2. The modified interception amount was 15.88-53.85t/hm2, which followed the order of M.shiluensis>M.crassipes>M.foveolata>M.sinicum>M.odora>M.lucida>M.maudiae. The water-holding function of M.shiluensis and M.crassipes litter layer was good. 3) Semi-decomposed litter could be saturated in 8 h and undecomposed litter reached saturation in 10h, the water-holding capacity had logarithmic relationship with soaking time (R2>0.92); the absorption rate changed the most within the first 2h of soaking and there was a power function relationship between water absorption rate and soaking time (R2>0.94). 4) The mean soil bulk density of different plants varied from 1.22g/cm3 to 1.55g/cm3, and the total porosity varied from 40.03% to 49.89%. The saturate soil water holding capacity was about 400.34-498.95t/hm2, and the effective soil water-holding capacity was about 26.23-70.33t/hm2. The water-holding capacity of the soil layer was in the order of M.foveolata>M.crassipes>M.lucida>M.shiluensis>M.odora>M.sinicum>M.maudiae. A significant power function relation between infiltration rate and infiltration fitting time was found (R2>0.90). [Conclusions] The water conservation capacity of soil layer is higher than that of litter layer, which is the main part for hydrological effect of forest land. The water conservation capacity of M.shiluensis, M.crassipes and M.foveolata is better than those of other Magnoliaceae plants, which suggested to give priority to the mixed planting of M.shiluensis, M.crassipes and M.foveolata in the application of landscape.
Retrospective study for the role of vegetation on the gravity erosion on the Loess Plateau
[Background] Gravity erosion, mass failure on steep slope triggered by self-weight, is an important process controlling the sedimentary structures and growth patterns of the steep slope, and the gravity erosion is also one of the major sources causing large amount of soil loss to the lower reaches. Under the national strategy to promote the high-quality development in the Yellow River Basin, the relationship between the vegetation and gravity erosion in the ecological management on the Loess Plateau has received more and more attentions from China. [Methods] Using a comprehensive and selective citation of the references around the world together with an in-depth discussion, this paper discussesd the occurrence mechanisms and research methods of the gravity erosion, as well as the effects of vegetation on soil loss caused by gravity erosion in the small watersheds of the Loess Plateau under the ecological management. The existing problems and future research highlights were also pointed out based on the above analysis. [Results] In previous studies, a variety of techniques have been used to estimate the gravity erosion on the Loess Plateau, each with intrinsic limitations and uncertainties. Presently, various methods, including onsite monitoring, onsite survey, field experiment and laboratory experiment, have been used to obtain the original data of gravity erosion on the gully sidewall covered with plants for analyzing the effects of vegetation on gravity erosion. A laboratory or field experiment may show the role of vegetation during the dynamic process of gravity erosion and the experiment is an effective way to study the micro-mechanism of gravity erosion. In contrast, the data of gravity erosion on a large scale can quickly obtained via remote sensing monitoring and the method may provide a reference for macro decision-making on soil and water conservation. Furthermore, the first-hand data observed via onsite monitoring or investigation from the real watershed may be used to testify the realizability of the result from the field or laboratory experiments. The previous studies show that soil erosion from the gully sidewall has not been obviously alleviated due to the serious gravity erosion although the ecological management has been greatly developed and the vegetation have been well restored in the small watersheds of the Loess Plateau. [Conclusions] The contribution of gravity erosion to sediment yield under the influence of vegetation and the complex relationship between the vegetation and gravity erosion need to be further explored. In the near future, to propose a new method is necessary in order to obtain the distribution information and development mechanism of gravity erosion and to evaluate the role of vegetation in conserving soil and water in the small watersheds on the Loess Plateau, China. Only has the mechanism of the gravity erosion been thoroughly understood, and then the theoretical framework can be constructed to study the gravity erosion in the area.
ZHANG Jiaqiong, YIN Minfeng, LIU Ying, DANG Zhen, BAI Ruru, SHANG Yueting, YANG Mingyi
Influence of fingerprinting properties and estimation models on sediment source discrimination via composite fingerprinting approach
[Background] The composite fingerprinting approach has been developed as one of the most important methods in sediment and contaminant source study, change tracing in erosional environment, and integrated management improvement of watersheds. Fingerprints and contribution estimation models are key aspects affecting the accuracy of sediment source identification, which further influence the tracing reliability of correlated contaminant source and erosional environment change, as well as the development of watershed management strategies. Thus, it is significant to understanding the impact of fingerprints and estimation models on sediment source. [Methods] This study summarizes research progress on the screening methods of fingerprints, selection of estimation models, and correction of key factors in models to clarify their impacts on the accurate identification of sediment sources using the composite fingerprinting approach. [Results] The selection of an optimal composite fingerprinting group or multiple composite fingerprinting groups had a significant impact on sediment source identification, which was also the case for the selection of different types of models. This was because fingerprints not only linked soil in source areas and deposited sediment, but also provided the basis for the selection of estimation models. Studies conducted in the same region suggested that sediment contribution from the same source varied up to 18.0% and 14.2%, respectively, when adopting different composite fingerprints selection methods and contribution estimation models. Thus, future research must enhance system study of the approach, and focus on solving the issue that previous studies lacked reliable validation of sediment source estimation using the composite fingerprinting approach through other reliable methods. It is urgent to obtain reliable and precise sediment source quantification data through scientific experiments using multiple techniques. Based on these precise verification data, further studies should first check and confirm the primary uncertainty sources affecting sediment source discrimination; second, select better fingerprints screening method; and third, improve contribution estimation models and algorithms of the key factors. [Conclusions] The ultimate objective is to improve the composite fingerprinting approach, and establish a normative methodology for the accurate quantification of sediment sources to serve the reasonable design of soil water conservation measures.