In this research, enrichment factor (EF) and pollution load index (PLI) were utilized to estimate the features of enrichment and contamination of PTEs in farmland soil. Furthermore, combining the spatial distribution characteristics of potentially toxic elements (PTEs) and positive matrix factorization (PMF) to distinguish and quantify the sources of PTEs in farmland soil, and then the potential ecological risk (PER) and human health risk (HHR) model based on PMF are applied to quantify the ecological and human health risks from different sources. Taking Puning District as an example, four sources of PTEs in farmland soil were quantitatively allocated. For ecological risk, the study area is at moderate ecological hazard level, and industrial activities were the greatest contributor. The mean E_r^i of Hg were 69.82, reaching medium ecological risk level. For human health risks, both adults and children have no evident non-carcinogenic risk in the study area. And natural source was the largest contributor to non-carcinogenic risk, followed by agricultural activities. With regard to carcinogenic risk, tolerable risks of soil PTEs in the study area were limited not only for adults but also for children. Furthermore, compared with adults, the health risks of children, whether non-carcinogenic or carcinogenic, were higher than those of adults, and the trends in health risks for children and adults were similar. A comprehensive scheme combining source contribution and risk assessment is conducive to quantitatively assess ecological risks, health risks and priority pollution sources, thereupon provide effective suggestions for protecting human health and preventing and controlling pollution.

Diversity-stability relationships in grasslands depend on the environment. Climate change and soil degradation potentially alter soil pH and community stability within grassland environments, although it remains unclear how soil acidity and alkalinity affect diversity-stability relationships. We conducted a three-year experiment of acidification and alkalization treatments in an arid grassland in northern China, and found that increasing and decreasing soil pH reduced community species richness, community diversity, community and dominant species asynchrony, and biomass stability. Soil acidification reduced community stability by reducing dominant species stability. Soil alkalization reduced community stability by reducing species asynchrony and dominant species stability. Acidification significantly enhanced the availabilities of soil NO3—N, P, and K, but did not affect the concentrations of soil total C, N, and P. By contrast, alkalization significantly reduced soil total C and N, but did not affect the availabilities of soil N, P, and K. Structural equation model analysis revealed that altered soil pH affected soil nutrients associated with species asynchrony and community stability, which indicated the importance of soil nutrients in driving community stability. Our results suggest that soil pH–mediated community stability is mainly driven by dominant species stability rather than diversity. This study provides novel insights indicating that arid grassland stability would be weakened under changing soil pH, subsequently leading to land degradation and reducing long‐term productivity and sustainability.

Governments and international donors are actively promoting laser-land leveller (LLL) technology to produce environmental benefits (i.e., avoid soil salinity, minimize soil erosion risk, and groundwater security) that could lead to sustainable agricultural production and averting land degradation. We investigate the adoption process of laser-land leveller (LLL) technology in Punjab, Pakistan during the period 1985–2018 using survey data from 504 farming households. A discrete-time duration model is used to investigate factors that could influence the speed of adoption of LLL technology and an endogenous switching regression (ESR) model to evaluate its impact on groundwater usage. It is found that about 70% of the surveyed households had adopted the technology. The key determinants of the speed of adoption include strong legal land entitlements, farm size, and farm location along the watercourse. Information acquired through formal and informal sources and exposure to the technology potentially reduce adoption time. The adoption of LLL reduces groundwater use by about 23% in wheat crop. These results highlight the need for improved institutional arrangements such as extension services, technology exposure, and establishing legal property rights over land to enhance uptake of LLL technology.

Biochar application is currently considered to be an effective soil organic carbon (SOC) management to prevent land degradation by enhancing SOC stock. However, quantitative information on the impact of biochar application on carbon dioxide (CO2) flux and associated microbial responses is still scarce, especially in degraded tropical agroecosystems. Here, we evaluated the impact of land management (control (C), biochar (B; 8.2 Mg C ha−1), farmyard manure (FYM) (M; 1.1 Mg C ha−1 yr−1), and a mixture of both (BM; 8.2 Mg biochar-C ha−1 and 1.1 Mg FYM-C ha−1 yr−1)) on CO2 flux, SOC stock, microbial biomass C (MBC), and metabolic quotient (qCO2) in degraded tropical alkaline cropland of southern India, based on a 27-month field experiment. Cumulative CO2 flux over the experiment was 2.4, 2.7, 4.0, and 3.7 Mg C ha−1 in the C, B, M, and BM treatments, respectively. Biochar application increased soil moisture and SOC stock, though did not affect CO2 flux, MBC, and qCO2, indicating the limited response of microbes to increased soil moisture because of small amount of SOC. Combined application of biochar and FYM did not increase CO2 flux compared with FYM alone, due to little difference of microbial responses between the M and BM treatments. Additionally, SOC increment (8.9 Mg C ha−1) and the rate of C-input retention in soil (0.78) was most significant in the BM treatment. Hence, the combined application of biochar and FYM could be sustainable land management by efficient increase of SOC stock in the tropical degraded cropland.

Understanding the soil and water conservation (SWC) impact of steep-slope agricultural practices (e.g. terraces) has arguably never been more relevant than today, in the face of widespread intensifying rainfall conditions. In northern Italy, a diverse mosaic of terraced and non-terraced cultivation systems have historically developed from local traditions and more recently from the introduction of machinery. Previous studies suggested that each vineyard configuration is characterised by a specific set of soil degradation patterns. However, an extensive analysis of SWC impacts by different vineyard configurations is missing, while this is crucial for providing robust guidelines for future-proof viticulture. Here, we provide a unique extensive comparison of SWC in 50 vineyards, consisting of 10 sites of 5 distinct practices: slope-wise cultivation (SC), contour cultivation (CC), contour terracing (CT), broad-base terracing (BT) and diagonal terracing (DT). A big-data analysis of physical erosion modelling based on high-resolution LiDAR data is performed, while four predefined SWC indicators are systematically analysed and statistically quantified. Regular contour terracing (CT) ranked best across all indicators, reflecting a good combination of flow interception and homogeneous distribution of runoff and sediment under intense rainfall conditions. The least SWC-effective practices (SC, CC, and DT) were related to vineyards optimised for trafficability by access roads or uninterrupted inter-row paths, which create high upstream-downstream connectivity and are thus prone to flow accumulation. The novel large-scale approach of this study offers a robust comparison of SWC impacts under intense rainstorms, which is becoming increasingly relevant for sustainable future management of such landscapes.

Understanding vegetation evaluation is critical for exploring changes in terrestrial ecosystems and identifying upcoming challenges. However, analyses that simultaneously examine abrupt changes in vegetation greenness at the national, regional, biome and pixel scales in China are still rare. Using long-term (1982–2015) satellite time series data in conjunction with the Breaks for Additive Season and Trend (BFAST) technique, we identified breakpoints in the Normalized Difference Vegetation Index (NDVI) in China. Results showed that the annual mean NDVI gradually increased during the 34-year period. 68.8% of the vegetated area exhibited upward trends in NDVI, most of which was distributed in Southeast China and the Loess Plateau. Changes in NDVI trends occurred in 78.7% of the total vegetated areas, while hotspots were concentrated in Northwest and North China. A rapid increase in breakpoints was detected after 1999, mainly concentrated in North and Northwest China, and corresponding to the times and areas with the highest ecological engineering efforts. Positive shifts in NDVI trends were more common and generally distributed on the eastern side of the Hu Huanyong line, while browning (negative) shifts were mainly distributed on the western side and were gradually expanding, indicating a possible tendency towards environmental degradation. Although unstable vegetation areas had higher frequencies of breakpoints, the proportion of stable vegetation experiencing NDVI trend shifts was higher after 2000, probably because human intervention buffered external disturbances in unstable areas. Identifying hotspot areas of shifts in vegetation greenness can provide scientific reference for sustainable land development and carbon neutrality target achievements.

The soil acidity level is a key soil characteristic that determines soil nutrient availability, soil microbial activities and crop growth. However, studies on distribution and extent of soil acidity in Ethiopia are not available. This study was carried out to predict the extent and severity of soil acidity. The study used 88,265 soil pH samples collected from soil laboratories and 21,439 samples compiled from studies. Rainfall, altitude, slope gradient, soil, and land cover were considered to generate spatial autocorrelation and integrated into geospatial analysis to predict the soil pH. The performance of the kriging model was found to be satisfactory with a standard error of 0.77, RMSE of 0.51, and R2 of 0.74. The model estimates showed that 47% and 30.2% of the country’s total area and rainfed areas were acidic (pH<6.5), respectively. Out of the total area of the country, 3.7% is found to be extremely to strongly acidic (pH<5.5), 20.7% is moderately acidic (5.6

The capacity of carbon sequestration of limestone soils in karst areas is unclear and needs to be studied, and there are few reports on the effect of calcium ions content on the migration and transformation of soil dissolved organic matter (DOM). In this paper, the leaching process of DOM from four-layered soil samples of two limestone soil profiles was systematically studied by soil column experiment with different Ca2+ concentration runoff. The results show that the elution of DOM can be divided into two stages, a rapid release and dilution stage and a nearly stable DOM release stage. After the elution, the average DOC loss rates are 61.9%, 75.5%, 70.9% and 49.1% for four samples, H1, H2, S1, and S2, respectively. When the Ca2+ concentration of eluent increases, the following phenomena occur: 1) The DOC loss rate decreased, which was reduced by 0.6-7.5% in this study. 2) The elution rate decreased and the desorption activation energy increased. 3) The molecular weight and the aromaticity of effluent DOM increased and decreased respectively. 4) The humic-like components were eluted less. The results demonstrate the higher Ca2+ concentration reduces the elution of soil DOM, improves the aromaticity of retained soil organic matter (SOM), and may inhibit SOM utilization and degradation by microorganisms. This study helps to understand better the transport and fate of SOM in karst regions, and provides theoretical support for soil planning management and carbon sink increase in karst areas.

Soil erosion is an important problem in the loess landscapes of Europe, resulting in a lowering of soil quality and landscape changes. As a result of soil erosion, SOC is redistributed and stored in SOC pools within the landscape. Understanding the SOC dynamics is important because changes in the SOC stocks may have large impacts on global climate change. Closed depressions (CDs) in loess landscapes collect colluvial sediments resulting from soil erosion and constitute sediment stores enabling the calculation of soil erosion phases and rates. CDs are also SOC pools enabling assessing of SOC erosion and storage in loess landscapes over long periods. Colluvial sediments and fossil soils, infilling five representative CDs in the Polish loess areas used for agriculture during several millennia, were documented. The mean SOC content in CDs were calculated, the area of CDs at the regional scale were mapped. Between 11.66 and 31.78 Mg of SOC are stored in each CD. The SOC within CDs represents a significant SOC storage in the landscape of the studied region and can reach values between 178.96 and 206.73 Mg·ha-1(mean 192.85 Mg·ha-1), the SOC content in the soil cover of the surrounding eroded slopes and plateaus is 102.38 Mg·ha-1. This study indicates that CDs are a key morphological features for a better understanding of the spatial distribution of SOC in agricultural used loess landscapes of eastern Poland. SOC storage in CDs needs to be taken into account when calculating total soil carbon storage at the regional scale.

High rates of erosion and runoff production on road infrastructure have been documented, indicating that unpaved roads might be significant sources of sediment in catchments. In this paper, the production of surface sediments from unpaved rural roads at different scales is assessed. The study took place in northeastern Brazil, in a semiarid area of the Caatinga biome, vulnerable to desertification. Sediment production data from road surface segments were monitored for two years (2013-2014) under conditions of natural precipitation. By using hydrosedimentological modeling and Geographic Information System (GIS), the sediment budget was calculated at the meso-scale basin (aprox. 930 km²), in order to identify the relative contribution of roads to the sediment balance. Universal Soil Loss Equation (USLE) associated with Maner’s sediment delivery ratio (SDR) equation, proved to be an adequate approach for predicting sediment yield on the road segment scale; the best results were obtained for the road without traffic, due to the non-interference in this segment of external factors, such as traffic and maintenance activities, not explicitly considered in the model formulation. The modeling procedure showed that the roads, which occupy only 0.7% of the catchment surface, were responsible for approximately 7% of soil loss in the area. Furthermore, sediment connectivity might be enhanced by roads, which cross the river network and, therefore, deliver more directly the sediment generated at hillslopes. This is particularly important in the studied environment, where sediment connectivity is low due to limited runoff and the existence of a dense network of surface water reservoir

Pesticide pollution has gradually caused land degradation. In order to avoid this problem, it is recommended to use enantiomeric pesticides that have less impact on the soil. The degradation of CYF enantiomers and the effect on soil functions are closely related to microorganisms. (+)-CYF enantiomer is degradable preferred and further discovered that related microorganism that degrades enantiomers. CYF enantiomers alter the bacteria structure and decreased the bacteria abundance. The combination of high-throughput and quantitative PCR results showed that the diversity of the (+)-CYF treatment was significantly lower than that of the (-)-CYF (-30.41 to 44.60) treatment and the (+)-CYF treatment (-27.80 to 56.70%) was more capable of causing the decrease in the number of soil microorganisms. In addition, (+)-CYF severely interferes with nitrogen cycling-related functions. Furthermore, the soil microbial structure was changed to its original level by enantiomers posed. In the study of nitrogen cycle function, we found that both enantiomers can restrain the abundance of nitrogen cycle-related genes, especially the (+)-CYF treatment decreased more. CCA showed that g-Massilia and g-Arthrobacter are closely related to nitrogen fixation genes and nitrification genes and degradation of the two enantiomers of CYF by g-Arthrobacter is closely related. The biological effects of cyflumetofen enantiomers remain unclear. Bioassay results show that enantiomers have similar virulence to Tetranychus cinnabarinus. Therefore, while achieving the prevention and control effect, the use of a single isomer (+)-CYF has a higher potential risk to the soil ecosystem.

In this study, we examined the effects of different mass ratios of aged refuse on Tagetes patula and rhizosphere microbes. The results showed that chlorophyll content and activities of superoxide dismutase, catalase, and peroxidase in leaf tissue increased significantly in plants cultivated in soil:aged refuse mixtures compared with ordinary soil, whereas levels of malondialdehyde and protein carbonyl decreased significantly in soil:aged refuse mixtures. Microbial community analysis revealed that aged refuse is rich in a variety of rhizosphere microbes that contribute to pollutant degradation, although microbial diversity was found to be relatively low. Bacterial genera such as Ferruginibacter, Hymenobacter, unclassified_Gemmataceae, Longimicrobium, Tychonema CCAP 1459-11B, Gemmatirosa, and Rubellimicrobium tended to be enriched to a greater extent in ordinary soil compared with soil:aged refuse mixtures. Correspondingly, bacterial genera such as Emticicia, Caedibacter, Anaerosalibacter, Tumebacillus, Patulibacter, Oceanotoga, Dyadobacter, Chloroflexus, and Acidobacteria bacterium SCN 69-37, Polycyclovorans, tended to be enriched in mixtures with a higher proportion of aged refuse. Functional prediction analysis revealed that rhizosphere microbe functions changed markedly following the addition of aged refuse. These findings indicate that aged refuse may represent a source of environmental stress for plants and modifies the dominant bacterial composition of rhizosphere microbes. The combination of organic or inorganic pollutants, plant physiological stress responses, and rhizosphere microbial community composition may have potential cooperative or dynamic equilibrium relationships. With respect to identifying potential approaches to recycling aged refuse, it will be necessary to focus on selecting optimal mass ratios of aged refuse and ordinary soil to control contaminant exposure.

Revegetation programs aim to avoid land degradation, control soil erosion, reduce floods, and improve ecological conditions. China has planted billions of trees over the past 20 years. However, little is known about the effectiveness of this artificial revegetation, and its consequences on China’s national conservation policies and changes in biophysical factors at the county level. Here we use satellite time series data and develop a new metric, the revegetation index (RVI), that quickly monitors revegetation and its long-term changes. We found that the amount of regions where the Grain to Green Program (GTGP) successfully was implemented only about 55.8% of the areas of GTGP implementation. Surprisingly, we provide observational evidence that the implementation of the GTGP can decrease soil erosion and drought, and increase water availability, but revegetation in the Yangtze River Basin (YRB) in China has a limited impact on soil erosion, water and drought. In particular, for revegetation between 1999 and 2016, indicating that previous an assessment by the government revealed as official statistics may have overestimated the effects of the ecological restoration practices.

Cadmium (Cd) pollution in soil pose a grave threat to human health. Combining various approaches to reduce Cd accumulation in crops is an active area of research to remediate farmlands with medium-high levels of Cd contamination. The Mercapto-functionalized palygorskite (PGS-SH) and zinc (Zn) application alone or in combination was investigated to explore reduction of Cd uptake in B. chinensis L and transformation of Cd in soil. The sole application of Zn or PGS-SH increased the biomass of B. chinensis L. and decreased the concentration of Cd in plants, but more improvements were observed from the combined application of Zn and PGS-SH. Low concentration of exogenous Zn (50 mg/kg) significantly increased the soil respiration rate (SRR) and the soil dehydrogenase activity (sDHA), while promoted B. chinensis L. growth while inhibiting Cd uptake. However, excessive exogenous Zn (≥ 200 mg/kg) significantly inhibited B. chinensis L. growth and soil microbial activity. The combined application of PGS-SH and Zn had the highest sDHA (145.59%) and lowest transport factor (TF) (27.59%) compared with the CK. The combination of PGS-SH and Zn fertilizer is a safe and effective means for remediating Cd-contaminated soil and restoring microbial activity.

This special issue is the second published after the Global Symposium on Soil Erosion (GSER, 15-17 May 2019, Rome, Italy) and includes contributions dealing with the 2nd theme of the GSER: Policies and practices in action to address soil erosion. While there is a good scientific understanding of the physical measures that can be used to prevent or mitigate soil erosion, the main constraints to progress often relate to policy development and or implementation as well as socio-economic aspects that provide limitations to implementation of sustainable soil management (SSM) practices including those directed to control erosion. There are no right or wrong answers to which policy or approach is most effective. Some combination of approaches needs to be adopted that work in the particular political, cultural, and socio-economic environment under consideration. The papers included in this special issue provide examples, from the national to local level, that could be adapted, or used, to improve uptake and implementation of SSM practices to prevent or reduce soil erosion. Regardless of what policy or plan is developed there has to be effective interaction with the local farmers and land managers as they are key to implementing any actions that will make a practical difference on the ground. Effective policies cannot be developed or implemented without bringing the land managers “on board” and the needs and limitations of the local farmers must be thoroughly understood and considered in any policy or plan development.

Ecosystem degradation is a process during which different ecosystem components interact and affect each other. The microbial community, as a component of the ecosystem whose members often display high reproduction rates, is more readily able to respond to environmental stress at the compositional and functional levels, thus potentially threatening other ecosystem components. However, very little research has been carried out on how microbial community degradation affects other ecosystem components, which hampers the comprehensive understanding of ecosystems as a whole. In this study, we investigated the variation in a soil microbial community through the extinction gradient of an ectomycorrhizal species (Tricholomas matsutake) and explored the relationship between microbial community degradation and ectomycorrhizal species extinction. The result showed that during degradation, the microbial community switched from an interactive state to a stress tolerance state, during which the interactivity of the microbial community decreased, and the reduced community interactions with T.matsutake marginalized it from a large central interactive module to a small peripheral module, eventually leading to its extinction. This study highlights the mechanisms of T.matsutake extinction due to the loss of soil microbial community interactivity, offering valuable information about soil microbial community degradation and the plant ectomycorrhizal species conservation.

Solar energy is increasingly used to produce electricity in Europe, but the environmental impact of constructing and running solar parks (SP) is not yet well studied. Solar park construction requires partial vegetation removal and soil leveling. Additionally, solar panels may alter soil microclimate and functioning. In our study of three French Mediterranean solar parks, we analyzed 1) effects of solar park construction on soil quality by comparing solar park soils with those of semi-natural land cover types (pinewood and shrubland) and abandoned croplands (abandoned vineyards); 2) the effect of solar panels on soil microclimate, CO2 effluxes and vegetation. We measured 21 soil properties of physical, chemical, and microbiological soil quality in one solar park and its surroundings to calculate integrated indicators of soil quality. We surveyed soil temperature and moisture, CO2 effluxes and vegetation below and outside solar panels of three solar parks. Soil aggregate stability was reduced by SP construction resulting in a degradation of soil physical quality. Soil chemical quality and a general indicator of soil quality were lower in anthropogenic (SP and abandoned vineyards) than in semi-natural (pinewood and shrubland) land cover types. However, differences between abandoned vineyards representing the pre-construction land cover type and solar parks were not significant. Solar panels reduced the soil temperature by 10% and soil CO2 effluxes by 50% but did not affect early successional plant communities. Long-term monitoring is needed to evaluate the effects of solar panels on vegetation.

The present paper attempts to study the causative physicochemical properties of the soils, which effectively portray its dispersive and deteriorating conditions, which have led to the formation of badlands in the Mandakini River watershed Chitrakoot area, India. Following investigations were made on the soil samples collected from the field: i) grain size distribution ii) various physicochemical properties and nutrient content of the soil. The clay minerals were detected and identified with the X-ray diffraction (XRD), Fourier transform infrared (FTIR), and High-Resolution Scanning Electron Microscopy (HRSEM). The spatial maps of all these parameters were prepared in a GIS environment, and overlay analysis was performed. The results show that the soil has a silt loam texture with high bulk density. The low values of plastic limit, liquid limit, and plasticity index show the non-cohesive nature of the soils. Higher bulk density has decreased the porosity as well as permeability in the soils. This impact on porosity and permeability has reduced the favourable conditions for vegetation, and the soils contain low organic matter. Apart from the bulk density, the presence of calcrete and illitic clay mineral (low in content) has also reduced the permeability of the soils, further increasing runoff. The overlay analysis based on the liquid limit, plasticity index, bulk density, and drainage frequency shows that the area is thoroughly affected by badland processes. Three zones were categorized as severe, very severe, and extremely severe depending upon their conditions gully channel processes.