LIU Xingrong, ZHANG Lianke, DONG Yaogang, SU Xing, WANG Xihong
Debris flow disaster induced by artificial accumulation site in loess area: An instance of Jianshui valley, Lanzhou city
[Background] The artificial accumulation site in the loess area is a new measure for Lanzhou city to expand the urban land space in recent years. It is inevitable to form more artificial landfill slopes at the edge of the site,which may become a potential material to be involved in debris flow.[Methods] This paper took the "4·19"debris flow disaster in Jianshui valley of Lanzhou city as an example. Combined with grain size analysis experiment, SEM image and field infiltration experiment, this paper discussed its characteristics and operation mode,and proposed corresponding treatment suggestions.[Results] 1)Materials with grain size <1 mm in the loess area accounted for 11.4 %-55.2 %,which was conducive to the initiation of debris flow. 2)Compared with two mud level survey sections with a distance of 170 m,the flow of the downstream section increased by 2.5 times,indicating that the loess subsidence caused by infiltration promoted the conversion rate of debris flow material. 3) The infiltration experiment showed that loess accumulation site had strong permeability. It basically reached a stable infiltration state in about 8 min under low water head conditions,and basically reached a stable infiltration state in about 12 min under high water head conditions. It caused soil softening in a short time, affecting the slope stability of artificial landfill site, and thus improved the material conversion rate of debris flow. 4) The flow pattern of debris flow induced by artificial accumulation site in the loess area is complex and changeable,which has the characteristics of wavy flow and intermittent flow.[Conclusions] On this basis,authors propose a prevention model that combines process management and key protection.
SONG Kepeng, LI Yifan, QU Siyi, ZHOU Fan, WANG Bin, WANG Shengping
Ensemble simulation for soil erosion of a typical watershed in the gully region of Loess Plateau on the basis of different algorithms
[Background] The Loess Plateau is one of the most severely eroded areas in the world,and quantification of soil erosion has been an important research work in the Loess Plateau of China.Although there exist many different soil erosion models for simulating soil erosion,few studies have used ensemble models to simulate soil erosion.[Methods] To investigate whether ensemble simulation can effectively improve soil erosion simulation,this study used the techniques of Bates-Granger (BG),equal weight (EW) and Granger-Ramanathan (GR) to integrate three widely used empirical-based soil erosion models,being Morgan-Morgan-Finney (MMF),Revised Universal Soil Loss Equation (RUSLE),and Chinese Soil Loss Equation (CSLE),respectively,for simulating soil erosion and sediment yield of a loess watershed,i.e., Xinshui River watershed.The training period (1991-2000) was for estimating the weight of each model,and the testing period (2001-2005) was for examining the applicability of the various ensemble approaches.The model performance was evaluated in terms of Nash coefficient (NSE),correlation coefficient (R),and root mean square error (RMSE),by against the measured sediment yield at the outlet of the watershed.Uncertainties of the model simulation were also evaluated by means of confidence interval.[Results] 1) The three individual models differed in their performances,with MMF performing the best compared with the other two.2)Ensemble techniques greatly improved the performance of soil erosion simulation,and reduced uncertainties among various modelling tools.Comparing the best ensemble simulation with the best individual model,performances of NSE,R,and RMSE were improved by 23.6 %,15.8 %,and 46.4 %,respectively.3)BG technique provided more accurate predictions than the other methods did, the width of the confidence interval for BG technique smaller than that of the others,indicating a more stable and reliable performance.[Conclusions] The performance of the widely used empirical soil erosion models (e.g.,RUSLE,CSLE) could be further enhanced by using the technique of ensemble simulation combined with uncertainty analysis in their applications.
YANG Dehui, WU Wangyang, GAO Bin, WANG Zhiqin, CHEN Dan
Analysis on characteristics of sand drift potential of the Poyang Lake sandy land from the year of 2005 to 2020
[Background] There are differences in aeolian activities and expansion velocity of sandy land in different parts of the Poyang Lake coast, which greatly affects the ecological environment and sustainable economic development of the Poyang Lake region. Therefore, strengthening the research on the wind regime and sandy environment of the Poyang Lake helps to understand the erosion patterns of the sandy land in Poyang Lake, and provides guidance for the key directions and regions of sand-control work.[Methods] Based on the wind data of seven meteorological stations along Poyang Lake from the year of 2005 to 2020, including Jiujiang, Lushan, Xingzi, Yongxiu, Duchang, Poyang and Nanchang. The value and direction of sand-driving wind and sand drift potential were calculated, and the characteristics of sand wind activity and wind energy environment of sandy land along Poyang Lake were analyzed and evaluated.[Results] 1) The fluctuation of sand-driving wind velocity in almost all stations decreased during 16 years, and presented the largest velocity in the northward directions and the highest sand-driving wind frequency (Fs) in winter versus the lowest in summer. 2) The sand drift potential (DP) showed a downward trend during the past 16 years, and the seasonal variation was larger, with spring and winter being larger than summer and autumn. The spatial heterogeneity of Poyang Lake was significant, and the spatial distribution was higher in the north and lower in the south, and higher in the west and lower in the east. The wind energy environment in the Lushan station was medium, while the other six stations were low. Moreover, The wind energy environment in the Lushan station was medium, while the other six stations were low. The DPs were primarily derived from north-to-northwest wind directions, which accorded to the south-to-southwest directions of resultant drift potential (RDP). 3) There was a significant regional difference in the wind direction variability (Cr), Nanchang and Yongxiu had large variability and single peak wind energy, and the other 5 stations had medium variability and double peak wind energy.[Conclusions] The spatial and temporal variation of drift potential was consistent with the variation of sandy land area. The resultant drift potential and sandy land area increased or decreased at the same time, and the high value area was distributed in the large sandy land area. It is suggested that the northwest of Poyang Lake, Duchang and Yongxiu should be the key areas of desertification control.
ZHANG Guojun, SHEN Ziya, WEI Xiaoyan, REN Zhengyan, XU Zhiyou, MA Wentao, CHENG Jinhua, WANG Xiao
Characteristics of sediment discharge in different underlying surface in the Yanchi area
[Background] The ecological environment of the Yanchi area is fragile, and sand erosion will affect the ecological environment and sustainable development of the region. Changes in wind erosion environments can be detected through a quantitative analysis of the dynamic wind erosion processes. Characteristics of changes in sediment discharge over long time scales affect to varying degrees the planning and implementation of sand management measures in arid regions. Quantitative analyses of sediment discharge and wind speeds on different underlying surfaces in the study area are of reference value for the deployment of wind and sand control projects on different underlying surfaces in the study area.[Methods] The wind speeds and monthly and annual weights of sand accumulation were measured at the Liuyaotou wind erosion experimental station, and the sediment discharge was calculated using the sediment discharge equation. The data was from five types of wind erosion samples (moving dune, semi-fixed dune, fixed dune, shrub-land and barren grassland) at the Liuyaotou wind erosion experimental station from 2010 to 2019. Immediately, sediment discharge concentration (RCD), sediment discharge concentration period (RCP), sediment discharge inter-annual variation coefficient (Sv), and sediment discharge inter-annual extremum ratio (Sw) were calculated. We also fitted the sediment discharge and wind speed by regression analysis to explore the response of sediment discharge to wind speed variation.[Results] 1) The underlying surface affected the magnitude and the uniformity of the sediment discharge, and there were some differences in the concentration and concentration period values of sediment discharge on five kinds of different underlying surfaces. The smallest average value of content and concentration was in shrub-land, indicating that the stable intra-annual variation occurred in the shrub-land. And the corresponding months of the concentration period were in May and June in shrub-land. The maximum annual sediment discharge in fixed dunes shifted forward over the course of the 10-year period. While the annual maximum sediment discharge in barren grassland shifted back in time. 2) Both the research on the inter-annual variation coefficient and the inter-annual extremum ratio indicated a higher degree of inter-annual variability of sediment discharge from the moving dune than from the shrub-land in the study area. The instability of the inter-annual variation coefficient from the moving dune was extremely high, and it was small from shrub-land. 3) The exponential function better reflected the relationship between sediment discharge and wind speed for the semi-fixed dune, for which the R2 was 0.843, while the best fit of sediment discharge and wind speed for the other underlying surfaces was the power function. 4) A cubic function was a good expression of the relationship between the average sediment discharge in each year and the wind speed in each year. The fitting formula was:Q=65.42-93.36V+42.55V2-6.00V3 (R2=0.800). There were two wind speed thresholds (1.74 and 2.99 m/s) that caused the response of the sand transport rate to wind speed to change.[Conclusions] There is an effect of underlying surface type on the variation coefficient and extremum ratio of sediment discharge. Meanwhile, there are critical values where the sediment discharged in response to wind speed. The results of this study could be used in the construction of wind and sand measures in the Yanchi region, providing a scientific basis and technical support for the comprehensive management of the Yanchi wind erosion region.
DING Lang, HAO Yong, SHAO Yan, LIU Chunyan, LIU Junlin
Analysis of influencing factors on the anti-scourability of tea tree slope
[Background] Among the many geological disasters on slopes, most of them are caused by failure to take timely and appropriate reinforcement measures. In recent years, with the national emphasis on the ecological environment, the topic of vegetation slope protection has gradually risen. In the mountainous area of Yuan'an county, Hubei, due to the large number of newly reclaimed tea (Camellia sinensis) gardens and lack of management, some areas have suffered from serious soil erosion. Therefore, this paper studied the effect of tea tree planting on the anti-scour performance of slope and the main factors affecting the anti-scour performance of tea tree slope, which was of great significance for analyzing the effect of tea tree planting on slope soil and water conservation.[Methods] A slope model was designed based on the regional environment of a tea farm in Yuan'an county, and the artificial climate simulation system environment box (model CABR-MCB) was applied to simulate the rainfall erosion test under the condition of extremely heavy rain. Then the effect of tea tree planting on the erosion resistance of slope was studied by calculating the runoff rate and anti-scour coefficient. Then the factors affecting the anti-scour performance of tea tree slope were analyzed based on the results of water stability aggregate content determination and root fractal scanning. Finally, SPSS software was used to analyze the correlation and significance of each influencing factor against the anti-scour coefficient.[Results] The runoff rate and anti-scour coefficient were calculated according to the erosion test data. The results indicated that the runoff first increased to the peak value, and then fluctuated and tended to be stable. Tea tree slope had the best runoff rate, which was smaller than the native vegetation slope and the plain soil slope (1.224 < 1.280 < 1.398). Compared with the native vegetation slope and the plain soil slope, the anti-scour coefficient of tea tree slope increased by 12.8 % and 53.2 %, respectively. The determination results of water stable aggregate content were as follows:Tea tree slope > native vegetation slope > plain soil slope. The above-ground development (vegetation coverage) of tea tree slope was better than that of native vegetation slope (95 % > 87 %). The development of the underground part of the tea tree slope vegetation was also better than that of the native vegetation slope.[Conclusions] After analysis, tea planting is conducive to improving the scour resistance of slope, which is affected by vegetation coverage, root development, water stability aggregate content, scouring time and scouring depth. The results of this research may provide ideas for solving the problem of soil erosion caused by newly cultivated tea plantations in Yuan'an area.
XIAO Yan, WEI Hui, MA Zhanlong, LENG Nuan, DENG Yusong
Effect of electrolytes addition on the stability of lateritic red soil aggregates in the south subtropical region
[Background] The southern subtropical region is an important agricultural production area in China. In this region, soil erosion and land degradation become seriously due to agricultural production, climatic conditions and other reasons. Soil quality can be influenced by exogenous electrolyte entering the soil during agricultural production and life. Aggregates are the basic units of soil structure and play an important role in maintaining soil fertility and soil structure. In this study, we investigated the effect of exogenous electrolytes on the stability of lateritic red soil aggregate developed from granite and sand shale in the southern subtropical region.[Methods] Sand shale lateritic red soil was collected from Wuming, Nanning, Guangxi and granite lateritic red soil from Longxu, Wuzhou, Guangxi. The selected study areas in both places are hilly terrain. The soil was collected from both sites in its original state and then air dried in the laboratory. The dry sieving method sieved out >3.00-5.00 mm aggregates. The aggregates of >3.00-5.00 mm of lateritic red soil developed from sand shale and granite parent material in the south subtropics were treated by three methods of Le Bissonnais method with 0, 0.05, 0.10, 0.20, 0.50 and 1.00 mol/L NaCl, KCl, MgCl2 and CaCl2 solutions as media.[Results] 1) The mean weight diameter (MWD) under fast-wetting treatments (FW), slow-wetting treatments (SW), and pre-wetting shock treatments (WS) showed a decreasing trend with the increase of electrolyte concentration. MWD values decreased faster before 0.10 mol/L and slowed down thereafter. 2) The particle size content of the aggregates changed with the increase of electrolyte solution concentration. When electrolyte solution concentration increased, the content of the >3.00-5.00 mm decreased. In three wetting treatments, the particle size content of granite lateritic red soil aggregates largely decreased with the decreasing of particle size, whereas the size order of the sand shale lateritic red soil aggregates was not consistent among treatments. 3) In static conditions, aggregate stability (AS) changed dramatically within the first 2 min of submersion in the solution, and the AS in pure water was greater than that in the electrolyte solution. 4) The stability of the 2 aggregates under different treatments was different. The stability of granite lateritic red soil aggregates was higher under dissipation and non-uniform expansion, and the opposite under mechanical crushing. The relative mechanical crushing index of both aggregates was smaller than relative shaking index, indicating that both aggregates were more sensitive to dissipative effects.[Conclusions] This study shows that electrolyte addition can reduce the stability of aggregates and change the aggregates particle size content. The stability of the aggregates can be changed significantly within a short time when submerged in solution. These results provide reference for soil improvement, soil conservation and sustainable utilization of cultivated land in the southern subtropical region.
LI Yunpeng, LI Hongjun, YAO Jialin, TAO Shuangcheng, YANG Hongfu
Vegetation restoration effects on the highway shopes of the cold and dry areas in Northwest China under four protection forms
[Background] With the rapid development of highway construction, the highway networks gradually develops from plain to mountainous area and from southeast to northwest of China. In process of highway construction, slope protection and vegetation restoration in the northwest region bring many difficulties to the builders. Masonry protection can remain slope stable, but it brings damage to the ecological environment. Reasonable use of slope protection can improve the effect of vegetation restoration better in the construction of highway.[Methods] According to the characteristics of environment and geology and geomorphology in cold and dry areas, four methods such as planting grass in three-dimensional web, honeycomb cell, planting grass via sowing seeds and planting grass via ecological bag were selected to explore the influences of different protective forms on soil environment construction and plant life. Basic physical properties of soil, plant composition, root growth were used to compare the effects of different forms of protection on vegetation restoration in slope.[Results] Four vegetation restoration methods had ensured plant growth on several levels, but the effects of vegetation restoration on soil environment and plant growth were different. Method of honeycomb cell and planting grass in three-dimensional web could improve the soil conditions and ensure the plant growth well, which remained soil moisture not less than 22 % and vegetation coverage not less than 85 %. Followed by planting grass via sowing seeds and planting grass via ecological bag, which remained soil moisture not less than 18 % and vegetation coverage not less than 65 %. Planting grass in three-dimensional web and planting grass via sowing seeds were beneficial to the growth of plant roots, which showed higher root growth depth (14.7 cm in average) than other methods. Honeycomb cell had the maximum root number of 179 and root area ratio of 0.023 2 within 5 cm soil depth.[Conclusions] For the vegetation restoration of highway slope in cold and dry area, honeycomb cell was recommended for slope vegetation restoration. While method of planting grass via ecological bag could be adopted for the slope with stable demand when carried out slope protection.
Effects of different vegetation types on the surface soil properties of mine waste site
[Background] In order to explore the suitable vegetation types for improving the soil quality of open-pit abandoned land, four forest-grass composite types of Cynodon dactylon (G), Ziziphus jujuba + C. dactylon (SG), Z. jujuba + Vitex negundo + C. dactylon (SJG), and Ailanthus altissima + Ulmus pumila + Z. jujuba + C. dactylon (CYSG) were used as the dominant plants in Jinshan mining area of Dongping county, Tai'an city.[Methods] Based on the 4 typical shrub-grass communities with the bare land in the same section as a control, and 3 soil samples of 0-20 cm soil layer using 5-point method were collected in eachplot. Physical parameters such as soil bulk, porosity, moisture content and soil nutrient indexes such as organic carbon, available nitrogen, total phosphorus and total potassium were determined. Correlation analysis was conducted to explore the interaction among soil factors in different vegetation type. Principal component analysis was conducted and fuzzy mathematical affiliation function method was used to evaluate the potential effects of different vegetation types on soil improvement.[Results] 1) Vegetation cover significantly improveed soil quality, and different vegetation types had different effects on soil quality. 2) Vegetation coverage significantly improved the soil physicochemical properties and increased the soil porosity and moisture content in the abandoned land of the open pit mine, with the highest soil saturated water-holding capacity was measured in the SJG model, which was 65.99 % higher compared to the bare land. 3) Soil organic carbon, total phosphorus, available phosphorus, total potassium, available potassium and available nitrogen content significantly increased. Soil organic carbon and available nitrogen increased by 546.22 % and 652.97 %, respectively, in the SJG model compared to bare ground. Soil total phosphorus and available phosphorus content increased by 140.95 % and 493.44 %, respectively, in the CYSG model compared to bare ground. Soil total potassium and available potassium content were the highest in SJG model and CYSG model.[Conclusions] The mixed forest-grass model was better than the bare ground and single vegetation restoration model in improving the soil moisture and physical and soil nutrients of abandoned mine land. The comprehensive improvement effect of different vegetation types on the abandoned land of open pit mine in Jinshan mine area of Dongping County was SJG>CYSG>SG>G.
Comparative analysis of soil chemical properties under cotton continuously-cropping and cotton-Jiashi melon rotated-cropping modes
[Background] Jiashi county in Xinjiang is a typical cotton-growing area and is also famous for its fruit product of Jiashi melon. This paper aims to explore the rotated-cropping mode of these two agricultural products to investigate how it affects soil chemical properties and compare it to the cotton continuously-cropping mode, and also to provides theoretical support for optimizing agricultural production and planting mode.[Methods] Soil chemical properties index under cotton continuously-cropping (abbreviated as continuously-cropping) and cotton-Jiashi melon rotated-cropping (abbreviated as rotated-cropping) were compared and analyzed based on field soil sampling. The soil samples were collected from two kinds of cropping soil in the surface (0-20 cm), middle (20-40 cm), and bottom (40-60 cm) layers. Soil chemical indices were measured through indoor index analysis, and the distribution characteristics of soil organic matter, total salinity, pH, and salt base ions between the two cropping modes were compared based on t-test and homogeneity test. The variation trend of soil chemical properties and nutrients was explored.[Results] 1) The soil organic matter content distribution characteristics under the two cropping modes differed in the study area. The average organic matter content in the different layers of the rotated-cropping soil showed as middle > surface > bottom layer. In the continuously-cropping soil, the average organic matter content showed as surface > middle > bottom layer. 2) The organic matter contents in both modes showed a decreasing trend with the increase of cropping years. Among them, there was a low organic matter content in the continuously-cropping soil, and the variation was small. There was a high organic matter content in the rotated-cropping soil, but the variation was considerable. 3) With the increase of planting years, the total salt content in the soil surface and middle layers of the rotated-cropping showed a decreasing trend, while the continuously-cropping soil showed an increasing trend.[Conclusions] The results indicate that the organic matter content in the soil surface and middle layer increases in the rotated-cropping mode, and the content shows a decreasing trend with the increase of years. There is little difference in soil salt ion content between the two cropping modes, but the total salt content of the rotated-cropping soil was higher than that of the continuously-cropping soil. The results provide a scientific reference for optimizing the soil organic matter and the content of each salt base ion through the Jiashi melon and cotton rotated-cropping pattern.
CHENG Hui, ZHONG Xiaojian, LI Zhiguang, WU Juan, LU Shunfa
Assessment on the role and capacity of carbon sink in managed Benggang
[Background] Benggang management is an important soil and water conservation measure in the southern red soil region, it plays a crucial role in maintaining ecosystem stability and improving the environment. However, research on the impact of Benggang management on carbon sink is still relatively limited. Thus, the objective of this study is to assess the carbon sink capability of Benggang management in terms of protecting soil and carbon, mitigating erosion and carbon emission, and promoting vegetation and carbon sequestration, as well as the differences in carbon sink capacity among different management models.[Methods] We selected one un-managed Benggang (UB), one Benggang with a comprehensively managed (MB) and three Benggangs with a land cultivation and afforestation Bengang managed (AB) as the research objects in Anxi county, Fujian province. Soil samples were collected at intervals of 0-10, 10-20 and 20-40 cm from different depths in all selected Benggangs. SOC (soil organic carbon) was determined using a carbon-nitrogen analyzer. Soil bulk density was measured using the ring knife method. Data on tree species, diameter at breast height, and tree height were obtained through field surveys and sampling methods. The tree biomass was quantified using biomass equations and harvesting methods.[Results] 1) Benggang management effectively protect soil and carbon, mitigate erosion and carbon emission, and promote vegetation and carbon sequestration. The carbon conservation, carbon emission reduction, and carbon sequestration capacity of MB are 32.00 t/hm2, 23.47 t/hm2 CO2 and 35.86 t/hm2 CO2, respectively. Those of AB are 3.97-9.42 t/hm2 C, 2.91-6.91 t/hm2 CO2 and 73.77-727.98 t/hm2 CO2, respectively. Based on this calculation, the managed Benggangs may increase carbon sequestration by 399.73×104 t CO2 in Anxi county. 2) The carbon sequestration effect of AB primarily relies on the enhancement of vegetation carbon stocks, accounting for 51.24 %-97.35 % of the total carbon sequestration, while for MB, it mainly relies on the enhancement of soil carbon stocks, accounting for 72.39 % of the total carbon sequestration. 3) The carbon sequestration capacity of AB is higher than that of MB. The main reason for the difference between the two methods is the afforestation and management practices employed. 4) After approximately 10 years of Benggang management, the soil carbon density of the managed areas is currently lower than that of degraded following vegetation restoration in the southern red soil region. This suggests that there is considerable potential for improvement in the soil carbon density of Benggang management.[Conclusions] Benggang management serves as a measure to prevent water and soil erosion and promote soil carbon conservation, and to reduce carbon emission, and carbon sequestration in the red soil hilly areas of southern China. The findings may provide scientific support for the selection of future Benggang management models and the assessment of their carbon sequestration capacity.
Thoughts on the measurement, monitoring and evaluation of carbon sink in soil and water conservation under the perspective of “carbon neutralization and carbon peak”
[Background] Soil and water conservation measures possess a strong carbon sequestration capacity. Through methods such as trapping sediment, conserving soil, nurturing vegetation, they regulate surface runoff, thereby reducing carbon emissions caused by soil erosion. This is beneficial for consolidating and increasing the capacity of the ecosystem's carbon reservoir. The measurement, monitoring and assessment of carbon sinks via soil and water conservation is not only a prerequisite for integrating carbon sequestration from these projects into carbon trading markets or for voluntary emission reduction, and represents a crucial measure in supporting the "carbon peak, carbon neutralization" strategy. These measures may provide a theoretical basis for comprehensive soil and water conservation management policy in the future.[Methods] We collected numerous literature retrieval with the keywords of "soil and water conservation" "carbon sink" and "measurement, monitoring and assessment" in the Web of Science, ScienceDirect,Springer and China National Knowledge Infrastructure (CNKI) databases. Representative literatures were selected for integration in the previous studies by the end of 2022. Specifically, we summarized the development potential of carbon sinks based on relevant policies and research findings under the "carbon peak and carbon neutralization" strategy. We clarified the concept, application, evaluation, and certification system of measuring soil and water conservation carbon sinks.[Results] 1) Carbon sequestration measurement and monitoring in soil and water conservation involve the investigation and monitoring of the net carbon sink quantity within a certain area. This is done by surveying and monitoring changes in carbon storage, greenhouse gas emissions within the boundaries, and the relevant data required for leakage. These data are then archived and used to construct empirical models for simulation and estimation. The main methodologies include field surveys, micrometeorological methods, remote sensing techniques, among others. 2) The quantification and monitoring of carbon sequestration in soil and water conservation are inherent requirements for serving the "dual carbon strategy." They serve as essential foundations for soil and water conservation planning and contribute to the intrinsic driving force for enhancing ecological service functions, which are vital for implementing the "two-carbon" strategy, water conservation planning, endogenous power, and various application scenarios such as carbon trading, ecological enrichment, and investment mechanisms. 3) Strengthening the construction of soil and water conservation carbon sink assessment, classification management, and certification system is crucial. Improving carbon sink investigation and monitoring technology and methods will provide theoretical and technical support for accurately assessing soil and water conservation carbon sinks, ultimately contributing to the goal of carbon neutrality.[Conclusions] Overall, this study points out that the measurement and monitoring system for soil and water conservation holds substantial long-term development potential. This includes improving the development methodology, establishing assessment indices, continuously exploring the growth potential of soil and water conservation carbon sinks, enhancing the diversity of soil and water conservation measures, expanding investment channels, improving the trading mechanism, and promoting the participation of soil and water conservation carbon sinks in carbon market trading.
HAO Haoxin, LÜ Fengling, YAN Fengling, GUO Zhonglu
A plant functional trait-based framework for ecological restoration of eroded land
[Background] Vegetation restoration is the main eco-engineering measure for controlling soil erosion and restoring degraded soils. Recently, scientists have proposed that biological measures for soil and water conservation in China should be oriented to enhance ecological function and should combine the specific ecological problems and social economic factors to set the ecosystem service as the major goal of the ecological restoration. To achieve those goals, managers and engineers require clear framework and tools.[Methods] Here, we introduced a trait-based approach as a powerful tool to understand the mechanism of soil erosion controlled by vegetation restoration. A literature review was conducted to investigate how plant respond to erosion stresses and how plant influence soil function on plant trait level.[Results] Based on the literature review, two key hypothesizes for applying the trait-based response-and-effect framework to control soil erosion were verified. 1) The intraspecific and interspecific variations in plant functional traits were significant heterogeneity. However, those variations were not entirely random, but rather influenced by environmental gradients. 2) Plant traits significantly affect soil ecological processes. With this context, we proposed a trait-based response-and-effect framework for ecological restoration on eroded land. That is, plant traits should be selected according to target restored ecosystem service (e.g., soil conservation, hydrological regulation and carbon storage). Firstly, the environmental stress factors of soil erosion and species interactions of the restored site should be clearly identified. Secondly, selected traits should not only affect the target ecosystem functions, but also not influenced by the environmental stress caused by erosional degradation (or inter-species interaction) or have stress tolerance. Furthermore, we summarized the erosion stress as drought, nutrient limitation, physical disturbance.[Conclusions] We believe that this framework could extend the current research ideas and practices of soil and water conservation vegetation measures, and have important practical implications for improving biological measures of soil and water conservation.
