Increased nitrogen (N) and phosphorus (P) availability, due to fertilization and deposition, is expected to influence soil microbial community structure and function. However, little is known about the sensitivity and dependency of soil microbial structure on the levels of N and P, and on the integration of N and P inputs in alpine meadow ecosystems. Here, we implemented a 3-year manipulative fertilization study with four levels (0, 10, 20, and 30 g m−2) of N fertilization, P fertilization, and NP fertilization (N and P fertilization at a ratio of 1:1) in a Tibetan alpine meadow. We examined how greater N and P availability affected bacterial community diversity, community structure in the top- (0–10 cm) and sub-top (10–20 cm) soil, network topological properties, and the potential mechanisms behind them. Although the α and β diversities of bacteria within top- and sub-topsoil were not significantly different from those in the control across N, P, and NP fertilization levels, the integration of NP fertilization significantly changed the relative abundances of more bacterial phyla than the N and P fertilization did separately. Furthermore, the N10 and N20 fertilization treatments strengthened bacterial interactions, whereas P and NP fertilization did not affect the complexity and connectivity of the soil bacterial co-occurrence network. In addition, the mechanism of structuring the bacterial community for separate N and P fertilization differed from that for NP fertilization. The separate application of N and P fertilization affected the bacterial community composition mainly through changes in the total and available P levels in the soil, respectively, whereas NP fertilization shifted the bacterial community composition through decreasing plant species richness. These findings provide a quantification of the response of soil bacterial diversity and composition to different levels of N, P, and NP fertilization. It also suggests that in the Tibetan alpine meadow, soil bacterial communities may alter their fitness according to the relative abundances of oligotrophic/copiotrophic bacterial taxa, rather than through changing their diversity.

Mulching measures can regulate soil properties; however, little is known about the effects metabolic limitations on farmland during the key growth stages of broomcorn millet in multiple regions of the Loess Plateau. We conducted field experiments to compare three techniques: flat planting with no mulching (TP), ridge–furrow mulching system (RF), and plastic film mulching (PFM). Soil extracellular enzymatic stoichiometry and physicochemical properties of three growth periods (jointing, flowering, and maturity) of proso millet (Panicum miliaceum L.) were measured to investigate microbial metabolic limitations and the relationship with soil moisture, temperature, and nutrients in the three regions of the Loess Plateau (Guyuan city, Huining County, and Yulin city). The results show that compared with TP, both PFM and RF techniques increased soil organic carbon (SOC), total nitrogen (TN), ammonium nitrogen ( NH 4 + − N $$ {{\mathrm{NH}}_4}^{+}-\mathrm{N} $$ ), and nitrate nitrogen ( NO 3 − − N $$ {{\mathrm{NO}}_3}^{-}-\mathrm{N} $$ ) during the jointing period, but the levels decreased during the flowering period, and the activities of C-, N-, P-acquiring enzymes were 29.02%, 33.68%, and 19.46% higher when using PFM, and 13.78%, 6.81%, and 6.52% higher when using RF. Meanwhile, RF treatment significantly increased the carbon metabolism limitation during the jointing, flowering, and maturity periods of proso millet in the three regions, and also improved the nitrogen metabolism limitation during the jointing and flowering periods of proso millet in the Huining and Yulin regions. Linear regression analysis showed that pH, SOC, and NH 4 + − N $$ {{\mathrm{NH}}_4}^{+}-\mathrm{N} $$ contents significantly affected carbon limitation, and nitrogen limitation was gradually alleviated with increases in SOC, TN, and NO 3 − − N $$ {{\mathrm{NO}}_3}^{-}-\mathrm{N} $$ contents in proso millet farmland soils. Partial least squares path modeling showed that soil moisture and nutrients differed significantly among the regions, and soil temperature positively regulated the soil nutrients. Mulching significantly improved the carbon limitation owing to increased soil temperature and moisture. These results provide important ideas for nutrient cycling and microbial metabolism of broomcorn millet farmland soil under mulching measures on the Loess Plateau.

Soil salinization has become a global environmental problem with the potential to cause serious land degradation. Thus, improving salt-affected soils and enhancing the nutrient utilization efficiency of saline farmlands through scientific and effective measures are urgent scientific problems. In this study, a 2-year field experiment was conducted to evaluate the effects of different soil amendments and their combinations on the dynamics of soil salinity, soil nutrients, and crop yield in a moderately salinized soil (EC1:5 of 0.78 dS m−1 and total salt content of 3.06 g kg−1). Nine soil treatments were implemented: biochar (B), lignocellulose (L), humic acid (H), fulvic acid (F), biochar + humic acid (B + H), biochar + fulvic acid (B + F), lignocellulose + humic acid (L + H), lignocellulose + fulvic acid (L + F), and control (CK). The results demonstrated that the application of F led to a certain reduction on the contents of soil salt, Na+, and Cl− among the soils amended with a single amendment application. The combined application of B and F or H could increase the soil desalination rate and increase the mineral N and Olsen-P concentrations at a soil depth of 0–20 cm, which improved the grain yield, biological yield, N recovery efficiency (REN), N agronomic efficiency (AEN), N partial factor productivity (PFPN), P agronomic efficiency (AEP), and P partial factor productivity (PFPP). Although the single application of L led to decreases in the grain yield, biological yield, REN, AEN, PFPN, REP, AEP, PFPP, and P physiological efficiency (PEP), the combined application of L and F had superior effects on enhancing the winter wheat grain yield and accumulative nutrient use efficiency. In conclusion, the combined application of B and F or H is recommended to ameliorate salt-affected soils and improve nutrient availability.

In light of the recent pressure from global warming, extreme drought events, and deleterious human activity, the strength and long-term change trends of vegetation in karst regions—in terms of their resistance to external disturbances—have not been studied systematically. Therefore, herein, we quantified the vegetation resilience and its nonlinear change trends in south China karst under different environmental gradients by measuring the lag-1 autocorrelation to time-series Normalized Difference Vegetation Index (1990–2018), clarifying the driving forces of vegetation resilience changes. It was shown that the vegetation resilience change in south China karst was not monotonous. In the first stage (pre-2002), precipitation and warming promoted the increase of regional vegetation resilience (slope = −0.045, p 25°, the vegetation resilience increased most obviously and the resilience of meadows was the largest, which can be the preferred vegetation type for ecological restoration projects. This research provides another perspective to understand karst vegetation ecosystem and the results will facilitate the protection of karst ecosystems.

It is challenging for a single development subject to complete complex scientific research tasks due to the peculiarities of saline–alkali land. Collaborative innovation and cooperation can help break through the common critical technology R&D problems in the development process by sharing information, technology, knowledge, and resources. However, the process of saline–alkali land development in China is slow and the transformation rate of research results is low. Few articles analyze the current situation and driving mechanism of the collaborative innovation network for saline–alkali land development from the perspective of the innovation chain. This paper first constructs an undirected weighted collaborative innovation network from the upstream, midstream, and downstream levels of technological innovation for saline–alkali land development, analyzing the network's structural characteristics and spatial distribution features. Then uses ERGM to explore the internal and external driving mechanism for network formation from network self-organization, subject characteristics, and exogenous environmental factors. The results demonstrate that the distribution of the collaborative innovation network is relatively uniform. However, there are also clusters, and the clusters are mostly centered on universities and scientific research institutions. Both the development subjects and clusters present regional features. Centrality and transitivity are crucial to the internal driving mechanism. In the external driving mechanism, the Matthew effect is modest, and the homogeneity effect is considerable; Organizational and technical proximity play a positive role; Geographical and institutional proximity play a blocking role. This study also provides practical enlightenment for encouraging horizontal and vertical collaborative innovation of sustainable development of saline–alkali land.

Mosses may be useful in ecological restoration activities but are excluded from most native plant materials programs. Recent efforts have attempted to propagate mosses in controlled environments for deployment to boost the recovery of degraded field sites. Field re-entry and establishment have proven challenging, possibly because the moss materials are not field-ready. We compared the field establishment rates of mosses of the same species propagated using three methodologies carried out either in greenhouses or outdoors. In an attempt to chemically boost field-readiness, we amended each with either sucrose, an osmoprotectant, or abscisic acid, a stress response phytohormone, or neither. Mosses grown outdoors with only one initial fall irrigation event lost at least 30% less cover than outdoor-grown moss that was irrigated in spring and moss tissue grown in a fog chamber inside of a greenhouse. The addition of abscisic acid also induced a subtle difference, leading to about 10% less cover loss compared to controls. Ultimately, all treatments declined to only trace level moss cover at most after 3 years. From these results, we put forward the working hypothesis that growing methodologies more similar to field conditions and exposing mosses to environmental fluctuations are more likely to produce field-ready moss materials. Abscisic acid addition is promising as a way to delay the mortality of mosses introduced into a desiccating environment. To translate short-term relative differences to long-term success, these practices may need to be combined with techniques that reduce the stress experienced in the field.

Farmland abandonment is a gradual, complex, and fragmented process that varied with time and space. How to identify the abandonment-risk of farmland with a spatial explicit way is a challenge and a key step toward the efficient management and sustainability of regional agriculture. This paper introduced the quantification method of connectivity from landscape ecology, took the rural settlements as the source patches that farmers moved out with materials and energies into the sink patches of farmlands, and during the moving process the least-cost path among settlements means the highest connectivity and the lowest risk of farmland abandonment. Then the new integrated framework for spatially quantifying the abandonment-risk of farmland based on settlement connectivity combined with the least-cost model (namely the FARBSC framework) was put forward and validated at the Honghe Hani Rice Terraces (HHRT) in Southwestern China. The verification and accuracy comparison of the FARBSC framework to the composite indicators and the buffer zone analysis of settlement were all indicated the efficiency of the new method. For the HHRT region, according to the FARBSC framework, the risky, weakly stable, stable, and highly stable zone is occupied 13.5%, 43.3%, 36.7%, and 6.5% of the land, respectively. The FARBSC framework had provided a quick and convenient way to mapping the risk area of farmland abandonment, especially for data-lack remote rural mountainous areas, such rice terrace heritage sites in mountainous Asia. More detailed spatial data can be used to improve its accuracy in future studies.

Metals can accumulate in agricultural soils, presenting a serious threat to human health; therefore, it is important to analyze the quality of these soils to avoid possible harm related to their contamination in the future. Despite the importance of monitoring arable soil quality, few studies have examined the current state of Cu and Cd soil contamination through analysis of historical data and temporal trends in heavy metal content. Therefore, this study was aimed at analyzing the spatial variability of Cu and Cd content (expressed by toxicity indices) and assessing the level of contamination of arable soils in Poland over the last 25 years (1995–2020). The average Cu content in soil throughout the duration of the study was ~10 mg/kg. The average Cd content increased from 0.7 mg/kg (in 1995) to 3.4 mg/kg (in 2020). The evaluation of Cu and Cd soil contamination showed that soils contaminated with Cd and Cu constituted 1.4% and 2.3% of the total monitoring points, respectively. The geoaccumulation index and pollution index ranged for Cu from −5.23 to 3.09 (mean: −2.50) and from 0.02 to 6.40 (mean: 0.20), and for Cd from −5.23 to 6.92 (mean: −1.67) and from 0.01 to 60.58 (mean: 0.44). The soil was practically uncontaminated with Cu and Cd in 98.77%/98.92% and 93.44%/97.92% of cases, respectively. On a national scale, the contents of Cu and Cd in soils depend on soil properties (pH, C, OM, ST, and CM) to a very small extent. An assessment of the spatial distribution of Cu and Cd concentrations in Polish arable soils indicated regional differences related to the degree of industrialization/urbanization. The obtained results show the impact of human activity on the level of heavy metals present in soils.

Trenched and diked contours (TDC) are used in hilly arid regions worldwide to reduce runoff and soil erosion. The TDC is based on three parts: ‘runoff contributing area’, trench, and adjacent soil dike on the hillslope contours. Surveys over the Northern Negev indicate the hydrological interrelation between the inter-dike surface and the dike. This study hypothesized that all the TDC parts are hydrologically interrelated. The objective is to analyze the soil's physical properties that influence the interrelation from dike construction until maturation and the influences of these interrelations on soil fertility, salinity, and stability. TDC systems, also known as ‘Shikim’, were constructed by the KKL-JNF (Karen Kayemet L'Israel. The Jewish National Foundation) all over the hills of the Northern Negev, the semiarid region of Israel, from the 1950s until present, which gives the ability to analyze the dynamic of water flows inside the TDC s along their existence. The findings indicate three hydrological interrelations, (i) From the ‘runoff contributing area’ into the trench, which differs between the planted and un-planted types; (ii) From the trench into the dike; (iii) and water migration in the ‘dike’ medium. Along the TDC maturation, the intensity of biological influences on these interrelations increases, leading to increased water mobilization to the trench (planting strip) and into the dike medium. The water migration in the ‘dike’ leads to forming of a soil bed adequate for sustainable agricultural utilization in its' downslope face. The finding of this study will maximize the agricultural utilization of the TDCs and their profitability.

Over the last decades, the establishment of new fast-growing forest plantations has been prospering. Although the European continent has the lowest share worldwide of forest plantations out of its total forest area, the Portuguese reality contrasts this. Since the last century, eucalypt plantations have increased widely in Portugal, and nowadays, it represents 36% of the total country's forests. Consequently, the soils of these plantations are commonly targeted with intensive soil mobilization by heavy machinery before planting, which in the case of sloped areas, frequently results in bench terracing. This study aims to quantify the widespread bench terracing implementation over the last 20 years in the Caramulo Mountains in north central Portugal. To do so, an analysis of satellite imagery was performed with Google Earth Pro, which allowed determining the coverage of forest areas where new terraces have been implemented, and their respective temporal dynamics. These results were then compared with additional spatiotemporal databases on land cover, topography, and bedrock, in order to understand the drivers of terrace implementation. Till date, 15% of the forest area in the mountains of Caramulo is under terraces, and over the last 20 years, the construction rate of new terraced land decreased in time, from 4% between 2000 and 2004 to 2% between 2015 and 2019. Among the two bedrock types existent in the area, terracing was found nearly exclusive over schist bedrock type (97%), while few areas were implemented over granites (3%). Their distribution was found limited above 30° of slope angle while 39% were found implemented below 15° of slope angle, conflicting with literature recommendations. Terracing was also found to be a driver of land cover change in 12% of the newly constructed terraces, whereas 8% were constructed over previous pine plantations and 4% on shrublands. This study allowed identifying several knowledge gaps associated with terracing implementation. Therefore, the authors of this work suggest a multidisciplinary approach when planning new terraces for a better assessment of the benefits and impacts of such land management practices.

Precise assessment of soil organic carbon (SOC) storage requires understanding how vegetation and soil physico-chemical properties differ in SOC fractions. Therefore, we aimed to analyze the dynamics of aggregate-associated, labile organic carbon (LOC) fractions corresponding to depth to clarify the effect of vegetation and soil properties on water stable aggregate (WSA) mineral adsorption in subtropical, red soil with five vegetation restoration regimes. The results showed that the large macro-aggregate fraction dominated the degraded red soil, which had the highest content of dissolved organic carbon (DOC). WSA-associated, easily oxidized organic carbon (EOC) varied from 6.26 to 20.02 g/kg and was not affected by vegetation types. Schima superba pure forest significantly increased DOC (0.38 g/kg on average) and particulate organic carbon (POC, 7.92 g/kg on average), which had the highest biomass. Along with soil depth, WSA-associated POC declined, while exhibiting a growth trend with decreasing particle size, for example, the highest POC was found in <0.053 mm aggregates. The redundancy analysis ordination indicated that soil porosity and total nitrogen (TN) were the main soil parameters that explained the most variance. Meanwhile, the vegetation biomass, except for litter, were all significantly positively correlated with <0.053 mm aggregates. Leaf biomass played the most important role on DOC in macro-aggregates with a 53.42% contribution. For aggregate-related POC, the largest contribution was from the interactions between branch biomass and pH (47.78%) followed by TN (35.1%) of micro-aggregate-related POC. Leaf biomass, <0.053 mm aggregates, and TN can be used as indicators to evaluate the impact of vegetation restoration on WSA-associated SOC fractions. Broad-leaved forest or in combination with indigenous coniferous species was a better choice for SOC sequestration improvement in the study area for managing C supply, process, and flux in subtropical terrestrial ecosystems.

Water resources management is fundamental for rural communities in drylands, where water harvesting technologies (WHT) can be used for intercepting surface runoff and storing water in soils. The so-called “Marab” WHT was initially developed by Middle Eastern agro-pastoralists that reside or commute in semi-arid and arid rangelands. The Marab WHT is a macro-catchment measure consisting of earth dams and stone spillways along the contours of a lowland depression or floodplain. Dependent on the local context (i.e., climate, soil, management, etc.), the established Marabs show highly variable effectiveness and little scientific evidence is supporting the scaling out of the technology. This study aims at filling the knowledge gap on the Marab performance in different environments by simulating its hydro-agrological effects for different soils and climatic conditions using the AquaCrop model. A case study performed for a Jordanian Marab over three seasons (2019–2022) confirms its huge improvement potential for barley production. Through Marab-based farming, barley production reached 8.37 t ha−1 on average, versus highly variable 0.34 t ha−1 without the WHT. The simulation-based assessment of soil textures identified that silty soils have the largest potential for producing up to 9.25 t ha−1 barley, compared to 6.60 t ha−1 produced in clay soils. Assessing different climate scenarios, a slight increase in daily average temperatures (+0.5°C) led to a considerable production decline of 4%–8%, while a significant reduction of precipitation (−20%) decreased biomass production by a similar rate (4%–10%). This underlines the robustness of the “Marab” WHT to rainfall amount variation. However, simulations also highlight the sensitivity of timing and frequency of flood events: removing the last and the first flood event reduced biomass production by approximately 50% and 80%, respectively, while the barley fails to develop if both events were suppressed.

The local saline water resource has been widely used for soil water and salt managements in saline-alkali area. The soil desalinization is strongly affected by the infiltration mode, and the melting saline ice infiltration can obtain soil salt leaching effectively. In this work, four melting sections (S1, S2, S3, and S4) were divided artificially according to the changes in meltwater from 5 (W5), 10 (W10), and 15 g L−1 (W15) ice. Various saline water samples of the above four sections with different salinities and volumes were prepared and infiltrated successively into soil columns that were packed with the coastal saline soils. The infiltration parameters, distribution patterns of soil moisture, salt, and sodium adsorption ratio (SAR), and soil desalinization in different sections were investigated and analyzed. Results showed that the infiltration of higher salinity water in the initial section increased the infiltration rates of slightly saline and fresh water in the last section. A greater infiltration rate, cumulative infiltration, and infiltration depth were ranked as W5 80% of the total leached salt loads occurred in the S2 section for all treatments. Lower levels of soil salt contents and SAR developed within the later infiltration sections. Ultimately, the 30 cm desalinization layer was obtained among all treatments, and the treatments corresponding to the saline ice with higher salinity acquired lower salt contents and SAR values. These results indicate that the successive infiltration of water with various salinity levels, characterized by meltwater from saline ice, accelerated the infiltration process, and resulted in an obvious soil desalinization effect on the coastal saline soil.

Various earth observation (EO) data and related spatial technologies are employed to monitor land degradation (LD) and its impacts on the drylands. However, a comprehensive framework that integrates multiple data sources and metrics to generate a consistent output still needs to be explored. Furthermore, the lack of consistency and the limited reliabilities of existing approaches make it challenging to identify proper countermeasures (avoid, reduce, reverse LD) and support decisions to combat LD in line with the Land Degradation Neutrality (LDN) Framework. The “Multi-Layered Land Degradation Tracer (ML-LDT)” is a framework that addresses the above research gaps. It is based on a comprehensive framework that integrates data extraction, LD monitoring, and forecasting capacities and consists of three functional layers, that is, a base data processor, monitoring/modeling components, and a forecasting layer employing machine learning (ML) algorithms. ML-LDT has a state-of-art capacity to model wind erosion together with sand and dust storms (SDS), making it particularly suited to the arid lands most prone to these processes. It is implemented over cloud processors with open-source components based on industry standards. Therefore, the routines are easily adaptable to user requirements in LDN planning. We evaluated the ML-LDT framework in the Indian Thar Desert and Inner Mongolian drylands. The results showed the overall robustness of the procedures and that ML-based models provide good insights to forecast future LD/SDS patterns that can be used to simulate LDN scenarios and targets. We validated the forecasting results against LD maps and remote sensing observations.

Despite the promise to increase control and fight against deforestation, the new Brazilian Forest Code (BFC) allowed more flexible dimensioning and land use rules in areas of private rural properties intended for native vegetation protection, namely the Legal Reserve (LR) and Areas of Permanent Preservation (APP). Following a decade of BFC implementation, the promise was somewhat flawed, while oversight and monitoring of private rural properties were not as expected. Considering this worrying scenario, the objective of this study was to quantify and map the forest balance of private rural properties listed in the Environmental Rural Registry of Rio das Velhas hydrographic basin (Minas Gerais, 2002), to assess compliance with the BCF and detect potentially illegal deforestation. The total deforested area in 6216 (28.7%) registered private rural properties reached approximately 119,800 ha after 2008, 61,500 ha of which were suppressed without surplus forest of LR. Besides, nearly half of the private rural properties presented forest deficits in the APPs. In a vast majority of cases, the deforestation was potentially illegal, but only a small number of private rural property owners was made responsible for that. The deforested areas were concentrated in small sectors within the rural properties, which would facilitate the control of illegal native vegetation suppression if oversight and law enforcement had been effective. Our results are an alert and a subside to public institutions and rural property owners while developing and executing plans, programs, and projects focused on environmental regularization of rural properties, with the ultimate goal of preventing further land degradation in the basin.

Many coal mining areas overlapped with agricultural land in the world. However, surface subsidence and waterlogging brought on by coal mining inexorably harm the agricultural land. Soil moisture can reflect the variation of mining impact significantly according to the geographic features of the high underground water table, which shows significant spatial gradient variation within the subsidence basin. Previous studies have used site survey and unmanned aerial vehicle (UAV), which are not applicable to large-scale assessments of the ecological impacts and defining the scale of impacts. Here, we used the Google Earth Engine (GEE) platform and an optical trapezoid model (OPTRAM) to estimate the soil moisture distribution around 50 mining subsidence waterbody samples in eastern China. Based on the spatial variation in soil moisture, the impact boundary of coal mining was determined using buffer analysis and trend fitting. The results showed that: (1) The OPTRAM can well reflect the soil moisture distribution which shows a good correlation between estimated and measured values, with R = 0.83 and RMSE = 0.054. (2) The spatial trend fitting of soil moisture is suitable for evaluating mining impact, and the impact distances are in the range of 96–762 m, 80% of which are located at 128–436 m. We also find that 28% of subsidence waterbody buffer basins were heavily influenced by human activities, and the coal mining impact boundaries cannot be effectively identified. The study provides a new idea to quantify the ecological and agricultural impact boundary of coal mining, which could be applied to other similar regions across the globe.

Soil dissolved organic matter (DOM) plays a critical role in regulating the cycling of terrestrial biogeochemistry. However, the influence mechanisms of nitrogen (N) addition on soil DOM concentration are not well understood at the regional scale. We performed a meta-analysis of 1004 paired observations from 115 literature to explore how N addition affected the soil DOM concentration, including dissolved organic carbon (DOC) and nitrogen (DON), in China. Overall, N addition markedly stimulated the soil DOC and DON concentrations by 5.2% and 33.1%, respectively. This implied that the stimulation by increased N availability than the suppression by decreased soil pH played a more important role in the soil DOM concentration under N addition. The N addition level showed a significantly positive correlation with the soil DOC and DON concentrations under N addition. The N addition influence on soil DOC concentration was decreased along with the increase in initial soil total nitrogen (TN). This demonstrated the microbial N mining theory in the low N soils and the stoichiometric decomposition theory in the high N soils at the regional scale. The mean annual precipitation (MAP) potentially facilitated the leaching out of soil DON and displayed a negative impact on the soil DON concentration under N addition. The increased soil depth and initial soil pH depressed the soil DOC concentration whereas stimulated the soil DON concentration under N addition. This indicated that DOC mostly accumulated in the top soil and DON largely leached to the deep soil. And the initial soil pH with high value perhaps promoted the uptake of DOC for microbes and the solubility of DON, and thus resulted in the opposite influences on the soil DOC and DON concentrations. Our study provided a mechanistic understanding on N addition influence on the C and N dynamics of terrestrial ecosystem at the regional scale.

Ecological security is a vital component of regional security and significantly influences regional sustainable development. The assessment of ecological security is the cornerstone of relative research to coordinate ecological protection and economic developments. However, a framework that enables systematic assessment of the ecological security still needs further exploration. A framework that includes ecosystem organization (O), quality (Q), and services (S) was proposed to evaluate the ecological security in southeast Qinghai-Tibet Plateau (QTP) in this study. Results showed that: (1) From 2000 to 2020, ecosystem organization in the study area showed an improving trend, with 61.33% of counties experiencing an increase in O value; (2) The ecosystem quality showed an increasing trend, with the proportion of increased areas amounting to 54.46%, and the significantly increased area occupied 3.38% of the study area; (3) The total trend of ecosystem services decreased, among them, habitat provision and soil conservation both presented an increasing trend, while water yield performed a decreased trend; (4) The ecological security in the southeast of QTP has been improved, which increased in north of the study area and decreased in south part. Overall, our study provided a novel view to characterize the physical status of the natural environment and enriched the methodology of ecological security assessment. More attention should be received by the different roles of ecosystem organization, quality, and services in ecological security in future studies, which is helpful to reflect the current situation and changing trends of regional ecological security more reasonably and comprehensively.

Management practices are expected to influence the capacity of forests to mitigate climate change. However, the long-term effects of afforestation on soil carbon accumulation in response to contrasting management regimes remain poorly understood. Here, we combined organic matter fractionation with a nine-year-long organic fertilization experiment to investigate the influences of largely accepted practices such as biochar (BC) and biogas-slurry (BS) inputs on the accumulation of soil particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) in three soil horizon depths (0–25, 25–50, and 50–75 cm, respectively). Our results suggested that both BS and BC significantly enhanced the POC and total soil organic carbon (SOC) content but overall did not significantly influence MAOC. Moreover, the POC and MAOC was more responsive to BS than BC. Further, our analyses revealed that the effects of BC on POC and MAOC were indirectly regulated by changes in the SOC: total nitrogen (TN) ratio, while BS influenced POC and MAOC by regulating TN. However, the responses of MAOC to the infiltration of organic fertilizers into the mineral soil should not be ignored, especially under high BC levels. Our work revealed that management practices are critical for supporting the long-term capacity of new forests to accumulate soil carbon, thereby facilitating the provision of nature-based solutions in response to climate change.

Assessment of mine rehabilitation strategies including soil cover treatments rely mainly on soil physico-chemical properties or plant performance indices, while much less is known about the response of biological soil properties. This field study evaluated the response of soil mesofauna (Collembola and Acari) in soil cover treatments (mainly subsoil and subsoil) on mine tailings, with or without organic amendments. The field experiment was conducted in large (1 m3) units rehabilitated in 2014, and mesofauna in soil cores was assessed 7 years later. The richness of Collembola and Acari as well as the density of Acari increased with organic amendments. Collembola community composition changed with the addition of soil cover and organic amendments. The density and community composition of Acari were strongly positively associated with organic carbon. The density of Euedaphic Collembola decreased, whereas Hemiedaphic and Epedaphic forms increased with soil cover. The contribution of generalist and metal-tolerant species explained the high density of Euedaphic life forms in tailings. Species-specific traits for Collembola and Acari could play an essential role in explaining the response of populations to treatments, such as affinity for C-enriched habitats, food preferences, and sensitivity to heavy metals. Overall, it is recommended to use a multiple diversity indices approach, to collect data on the density and assemblage of mesofauna species to investigate the response of mesofauna communities to soil cover treatments. Mine tailings rehabilitation strategies should focus on improving the nutrient content of soil covers, since it benefits diversity and density of soil fauna.