Periphyton plays an indispensable role in coastal saline-alkali land, but its function is poorly understood. Soil physical and chemical properties (pH value, salinity, soil organic matter), enzyme activity and microbial diversity (based on 16s rDNA, ITS and functional genes) were measured in periphyton formed on rice-growing coastal saline-alkali soil modified by a new type of soil conditioner. The results showed that the content of organic matter and catalase activity in periphyton were significantly higher than in the unplanted control soil. Soil pH and salinity were decreased in periphyton compared to the unplanted control soil. Based on the relative abundance, bacterial genera Desulfomicrobium, Rhodobacter, cyanobacterium_scsio_T−2, Gemmatimonas, and Salinarimonas as well as fungal genus Fusarium were more abundant in periphyton than the unplanted control soil. In terms of functional genes, the cbbM and cbbL sequencing showed higher abundance of Hydrogenophaga, Rhodovulum, Magnetospira, Leptothrix, and Thiohalorhabdus, whereas the nifH sequencing indicated higher abundance of Cyanobacteria in the periphyton compared to the unplanted soil. The relative abundance and community structure of soil microorganisms were improved by periphyton, thus reducing soil salinity and pH, increasing soil organic matter and enzyme activity. This indicated that the periphyton can improve the conditions and offer a suitable environment for plant growth in coastal saline-alkali soil.

Abrupt changes in climatic factors, exploitation of natural resources, and land degradation contribute to soil erosion. This study provides the first comprehensive analysis of annual soil erosion dynamics in Pakistan for 2005 and 2015 using publically available climatic, topographic, soil type, and land cover geospatial datasets at 1 km spatial resolution. A well-accepted and widely applied Revised Universal Soil Loss Equation (RUSLE) was implemented for the annual soil erosion estimations and mapping by incorporating six factors; rainfall erosivity (R), soil erodibility (K), slope-length (L), slope-steepness (S), cover management (C) and conservation practice (P). We used a cross tabular or change matrix method to assess the annual soil erosion (ton/ha/year) changes (2005-2015) in terms of areas and spatial distriburtions in four soil erosion classes; i.e. Low (<1), Medium (1–5], High (5-20], and Very high (>20). Major findings of this paper indicated that, at the national scale, an estimated annual soil erosion of 1.79 ± 11.52 ton/ha/year (mean ± standard deviation) was observed in 2005, which increased to 2.47 ±18.14 ton/ha/year in 2015. Among seven administrative units of Pakistan, in Azad Jammu & Kashmir, the average soil erosion doubled from 14.44 ± 35.70 ton/ha/year in 2005 to 28.03 ± 68.24 ton/ha/year in 2015. Spatially explicit and temporal annual analysis of soil erosion provided in this study is essential for various purposes, including the soil conservation and management practices, environmental impact assessment studies, among others.

Mapping and monitoring the Trees outside Forests (ToF) is gaining significance in the scientific community as they provide critical ecosystem services such as protecting soil and water resources, wildlife habitat, energy efficiency etc. Also, quantifying ToF can provide useful information on emissions estimation in the Agriculture, Forests, and Other Land Use (AFOLU) category of the Intergovernmental Panel for Climate Change (IPCC). Despite the importance of quantifying ToF, very few studies have attempted to quantify them in India’s natural resource inventory programs. In this study, we focus on Haryana state, India, to map ToF using very high-resolution (VHR) Indian Remote Sensing (IRS) satellite data. Haryana’s landscape is highly interspersed with croplands and ToF, thus providing a challenging environment to test VHR satellite data’s ability to quantify the diversified landscape structure. We specifically used Cartosat-1 panchromatic (2.5m) and Multispectral LISS IV (5.8m) datasets to quantify the vegetation and build a much-needed database on ToF. We used a novel classification scheme based on the geometry, i.e., point, polygon, or polygon formations, to quantify ToF at 1:10,000 scale. Our results suggest ToF with the point, area, and linear block formations of about 2,774,531, 20.51, and 128.83 sq. km, respectively, accounting for ~3.38% of the total study area . Our study highlights the usefulness of VHR satellite data and fused imagery to quantify ToF in highly diverse landscapes, with the case study in Haryana State, India. The results will help address vital ecosystem services from ToF, including greenhouse gas emissions quantification from the AFOLU category.

Saline-alkali soils are widely distributed in China, affecting plant growth and sustainable development of ecosystems. This study characterized the effects of planting Melia azedarach L. on chemical properties and microbial communities in saline-alkali soils [bare (CK), bulk (BS) and rhizosphere soil (RS)]. Compared with the bare soil, planting Melia azedarach L. lowered salt content and concentrations of extractable Na, K, Ca, Mg and Cl-, but significantly increased organic matter, total nitrogen, total phosphorus, available phosphorus, soil urease activity and alkaline phosphatase activity in the rhizosphere soil. High-throughput sequencing results indicated that bacterial richness and diversity decreased in the order RS>BS>CK. The richness of fungi was ranked RS>CK>BS, and their diversity decreased in the order CK>RS>BS. The three dominant bacterial phyla were Proteobacteria, Actinobacteria and Bacteroidetes, and the three dominant fungal phyla were Ascomycota, Basidiomycota and Glomeromycota. Redundancy analysis indicated that total phosphorus concentration and alkaline phosphatase activity significantly influenced bacterial diversity, whereas soil Ca and Mg concentrations were closely related to the fungal community diversity. In conclusion, planting Melia azedarach L. improved soil properties, increased the diversity and richness of soil microbial communities, and thus ameliorated the saline-alkali soil.

Shrub encroachment (SE) has been occurring and studied worldwide over the last century. What remains to be investigated is how soil and vegetation characteristics vary under canopy of different species of shrubs for restoration goals. Thus, this study aimed to compare the effect of three shrub species (Amygdalus scoparia, Ebenus stellata, and Daphne mezereum) on soil and vegetation characteristics under their canopies in semiarid rangelands in Iran for restoration purposes of degraded areas. Fifteen sites were randomly selected in such three shrub species which were found close to each other in each site. Soil and vegetation characteristics were measured under the three shrubs, comparing with outside the shrub canopies (control). One-way ANOVA and non-metric dimensional scaling were used to clarify the differences of the effects of different shrub species on sub-canopy soil and plants. The results indicated that the effect of different species of shrubs on soil properties was not equal, more pronounced by A. scoparia. Similarly, the highest value of herbaceous Shannon-Wiener diversity index was recorded under A. scoparia (2.07) as compared with D. mezerum (1.76), E. stellata (1.41). The highest and lowest values of Menhinick richness index were observed under A. scoparia (3.43) and E. stellata (1.46), respectively. Compared with two other shrubs, a taller canopy in A. scoparia (3.50m vs. 2.60m and 1.83m) probably led to greater litter input by the shrub. Different effects of different species of shrubs on sub-canopy soil and vegetation should be considered in the restoration projects of degraded semiarid rangelands.

Soil degradation restricts the development of agriculture and the degree of soil degradation is related to land use type. Quick and efficient evaluation of the degree of soil degradation is needed for the timeous implementation of remedial measures to ensure soil sustainability. Earthworm community characteristics are closely related to soil management practices and soil quality and could be used for evaluation purposes. In this Loess Plateau study, the degree of soil degradation under nine different land use types (natural and planted woodland, shrubbery, and grassland, plus cropland, orchard, and abandoned land) was related to the earthworm community characteristics (density, biomass, and the Shannon-Wiener, Species richness, and Pielou’s evenness indices) using a soil degradation index calculated from soil physicochemical properties determined for each land use type. The earthworm community characteristics associated with a low degree of degradation were significantly higher than those associated with a high degradation degree. Compared to the artificially managed land use types, earthworms in the natural ones showed higher biomass, density, and diversity. The earthworm density, biomass, and Shannon-Weiner index were significantly correlated with soil organic matter and total nitrogen content. These findings indicate that earthworm community characteristics can comprehensively characterise the physicochemical properties and biological characteristics of soils under different land use types. Linear correlations showed a significant relationship between the soil degradation index and the earthworm community characteristics, indicating that the latter could be used effectively to evaluate and represent the degree of degradation of soils on the Loess Plateau over a certain degradation range.

Decomposition of forest litter plays a major role in nitrogen (N) dynamics in soil. But to which extent that forest litter affects soil N and how much soil N is derived from the new litter remains unknown. An in-situ soil column experiment with 14-month litter decomposition was conducted to examine the effect of litter retention on soil N dynamics in a typical forest of subtropical China in 2018. Litter removal in the soil column was used as a control treatment, while natural litter or identical amount of 15N labeled litter was added to soil columns as litter retention treatment. The results showed that litter removal caused a continuous decrease in concentration of soil soluble organic nitrogen (SON) in the first 5 months, and then SON began to accumulate and its concentration went up in spring showing obvious seasonal change. Litter retention accelerated the reduction of soil SON concentration in the first 2 months, while maintained a high concentration after that period. Soil NH4+-N derived from litter was nitrified rapidly, and newly formed NO3–N was quickly immobilized or lost. Only 1.8% of soil SON came from litter N and 98.2% from indigenous soil N under the decomposition of labeled litter. Litter provided supplementation N to form new soil SON continuously, however, only a small part of SON was relatively stable, and SON played the role of reserve and regulatory pool. Soil SON and TN were formed after long-term litter accumulation and decomposition.

Benzo[a]pyrene (B[a]P) as a representative polycyclic aromatic hydrocarbons is concerned by global scientists in various fields, but its biological and biochemical actions in soil-wheat systems are still rarely reported. The B[a]P as a ubiquitous soil pollutant possesses varied contents in real environment, and herein was studied in systems of soil and wheat to obtain relative results to reveal their variations in different systems. Its bioavailability (extractability and bioaccumulation) and basic biological toxicity were tested based on three typical soil types (red, black, and brown) in China and spiked amounts (0.1, 1, and 10 mg/kg) with several orders of magnitude. Results showed that B[a]P concentrations in soil-wheat systems extracted by HPCD were insignificantly (p > 0.05) higher than Tenax-TA, and varied with soil types and spiked concentrations. Besides, the root and shoot length were mostly inhibited, in a range of -21.85%-26.35% and -0.48%-54.85%, respectively, by B[a]P in different soil types and increased with its increasing concentration. Comparatively, higher bioconcentration factor and translocation factor values were observed under lower group in red soil-wheat systems, and higher spiked groups in black and brown soil-wheat systems. Moreover, inhibitive effects posed by B[a]P were mainly targeted at wheat shoots in these soils. The simultaneous studies provided a comparable knowledge of B[a]P in ecosystems of different soil types combined with different plant species due to lots of variations, further to serve for contaminated soil remediation and sustainable agricultural management.

Farmlands contamination with heavy metals (HMs) can be considered as a global issue especially in developing countries. The current study investigates the various pollution indices, potential ecological risk index (PERI) and human health risk caused by HMs in some selected regions of Punjab Province, Pakistan. Farmlands soil samples were collected, acid extracted and analyzed via ICP-MS (Agilent 7500c) for selected HMs. All the HMs were found within permissible limits set by worldwide regulatory authorities except Cd which exceeded its limit in 68% agricultural soils of the study area. The CF values for Cd showed high (CF≥6) degree of contamination to considerable contamination (3≤CF≤6). The CD values indicated low (CD≤6) contamination to moderate (6dermal>inhalation. Furthermore, the RI values were observed higher than 1.0×10–4 for Cd (Lahore and Faisalabad regions) and Cr (Multan and Faisalabad regions) in children working in farmlands and likely exposed to high cancer risk. So, minimization of pollutants must be the top priority of the state to reduce contaminants inputs and immobilization in soil through environmental protection laws and regulations

Planting trees is one of the most effective activities in recovering soil organic carbon (SOC) stocks of degraded areas, but we still lack information on how different tree species can influence soil respiration, one of the main sources of dioxide carbon (CO2) to the atmosphere. This study aimed to explore the influence of different forest species on the autotrophic and heterotrophic components of the total soil respiration in a bauxite mining area under reclamation. We analysed the soil CO2 efflux under five treatments: i) monoculture of clonal Eucalyptus; ii) monoculture of Anadenanthera peregrina (L.); iii) a mixed plantation of 16 native forest species (Nat); iv) a mined area without vegetation cover; and v) a natural forest cover. This design allowed exploring the soil CO2 dynamics in a gradient of recovery, from a degraded area to natural vegetation. Additionally, we measured soil temperature, moisture and soil characteristics. Soil CO2 efflux increased with increasing forest species cover in the rainy months. There was no significant change in CO2 efflux among the tree species. Heterotrophic soil respiration contributed to 64% of total soil CO2 efflux and was associated with litter decomposition. Amongst the abiotic variables, increases in soil moisture had the most influence on CO2 efflux. Therefore, these results help to understand the factors that underpin the loss of SOC and can orient management practices to improve soil organic matter and restore soil quality in degraded areas.

The restoration of surface mining is a key to meet the global ecosystem restoration target. With increased data accessibility and computing tool capabilities, it becomes possible to expand mine restoration monitoring from single mine sites to multiple mine sites on a large scale. This study constructed a new index, Mine Landscape Restoration Index (MLRI), by coupling Land Surface Temperature (LST) and Enhanced Vegetation Index (EVI) to simultaneously monitor the restoration of regional multiple mine sites. We analyze historical and future trends of restoration using Mann-Kendall test, Sen’ slope, and Hurst exponent for MLRI time series. The restoration effects of 46 surface coal mine sites located in the northwestern ecologically fragile region of China from 2000 to 2019 were assessed, based on 3675 Landsat images on Google Earth Engine. The results showed that MLRI was effective in identifying restoration areas and processes in surface mine sites, which was validated by high-resolution images and field investigation of mine samples. The restoration area overall percentage was significantly higher in mines started mining before 2000 than after 2000. According to the restoration effects, we clustered the 46 sites into high, medium, and low restoration area percentage clusters with 13, 11, and 22 mine sites, respectively. Individual clusters have aggregation characteristics within each mine region, but are distributed irregularly across the different six mine regions. This study provides a new approach to monitoring the restoration of surface coal mine sites and inform government managers in developing mine restoration programs and sustainable mining development plans.

Hurricanes are extreme phenomena that affect the coasts of Mexico every year. The economic and biodiversity losses caused by these extreme events are extensive. However, little is known about the effects that these severe weather incidents have on Mexico’s forest conservation and protected areas. A hydrological characterization and regionalization of the storms caused by the rain fields generated by all the hurricanes that touched the Mexican coast from 1966 to 2017 were carried out. Adimensional Huff Curves are proposed to get precipitation hyetograms from which the erosion factor of a storm is obtained; using the Universal Soil Loss Method (USLE). The results made it possible to get the typical precipitation hyetograms in the forests and protected areas, before, during, and after the impact of a hurricane. The proposed hydrological regionalization made it possible to estimate the rainfall intensity in 30 minutes to characterize the start of rain erosion. The method proposed in this research was applied in the 177 Natural Protected Areas (25628239 ha), as well as in the 370 voluntarily designated areas for Conservation (399643 ha), in Mexico. It is concluded that, with the regionalization and the proposed equations, it is possible to get typical hurricane precipitation hyetograms, which would allow us to detail the forest management plans in forests, ecological reserves, and protected areas of Mexico.

We investigated the soil physicochemical property and arbuscular mycorrhizal fungi (AMF) resilience to the degradation and deforestation of the Chilimo dry evergreen Afromontane forest (CF). Topsoil (1-10cm) physicochemical property, AMF spore abundance (SA), and AMF infectivity were determined across four land uses, viz., natural forest (NF), shrubland (ShL), cropland (CrL), and grazing land (GrL). According to the PERMANOVA and NMDS results, soil physicochemical property was resilient to degradation (NF-ShL conversation) but not deforestation (NF-CrL or NF-GrL conversions) of CF. The one-way ANOVA results indicated that most soil physicochemical variables were significantly (p<0.05) affected by land-use change. Soil organic matter and total nitrogen, in particular, reduced significantly (p<0.05) by up to 48 and 57% due to NF-CrL and NF-GrL conversion respectively. Whereas SA was found to be resilient to both CF degradation and deforestation, AMF infectivity was resilient only to NF-CrL conversion. Generally, our results did not show a similar pattern in soil physicochemical property, SA, and AMF infectivity resilience to degradation and deforestation. However, in the case of NF-GrL conversion, both soil physicochemical property and AMF infectivity exhibited significantly (p<0.05) low resilience. Based on our results, we conclude that soil physicochemical property and AMF are important factors to consider in CF restoration planning. When planting sites are either the croplands or grazing lands, soil amendment could be recommended. AMF inoculation, however, could be recommended when the planting sites are grazing lands. These recommendations may also apply widely to dry evergreen Afromontane forests restoration but additional studies are required.

Rural communities in the drylands of Sub-Saharan Africa (SSA) derive their livelihoods primarily from their natural resource base. Unprecedented changes in these environments over the past few decades are likely to intensify in the future and land users need to develop sustainable adaptation strategies. This study aims to identify land use and land cover (LULC) changes and their drivers in a Sub-Saharan dryland, between 1986 and 2017, by integrating local knowledge and remote sensing analysis. Local knowledge and environmental perception are used as the basis for defining LULC classes and for training and validation of change detection. This study identifies bush encroachment into former pastures as the dominant LULC change with an increase of woodland by 39 % and a decrease of grassland by 74%. This process is perceived as severe degradation by local respondents and is linked to changing management regimes and unreliable rainfall patterns. Deforestation and woodland thinning can be traced back to increased habitation and farming, though the local community also identifies charcoal production as a driving factor. The integration of remote sensing and local knowledge provides a holistic view on LULC change in Pokot Central, Kenya, and offers a solid base for site specific and actor-centred management approaches necessary for sustainable pathways of drylands.

Understanding community restoration state and the corresponding assembly mechanism is helpful to assess the restoration measures and predict community dynamics. We collected plots by shrub cover (low, medium and high) in three Caragana mircophylla shrub-encroached grasslands which were fenced since 1979, 1983, and 2003 (fencing duration) in the northern China, to explore the effect of fencing duration and shrub cover on the community restoration by vegetation investigation and phylogenetic approach. There were significant differences in community composition among different fencing duration or shrub cover treatments. Species richness in the site of fencing since 1979 or in the plots of high shrub cover was relatively higher than that in any other sites or plots. By phylogenetic analysis, functional traits were phylogenetically convergent. Based on the standardized effect sizes of mean pairwise distance (SESMPD) ranged from -1.96 to 1.96 in six out of nine plots, which suggested that stochastic processes dominated community assembly. SESMPD were lower than -1.96 in the rest three plots which indicated that competitive exclusion drove community assembly. These results indicated that the increase of fencing duration or shrub cover could enhance competitive exclusion. The present findings highlighted the importance of shrub in influencing the community composition and community assembly, supporting that shrub-encroached grassland is another stable state in the semi-arid northern China. Therefore, it is essential to distinct shrub-encroached grassland from degraded grasslands when formulating relevant conservation and management measures in the semi-arid regions.

Wind erosion is the main form of soil erosion in arid and semi-arid areas. It leads to soil loss and land degradation, which aggravates ecosystem vulnerability and threatens regional sustainable development. The assessment of wind erosion and the study of its driving factors can reduce soil wind erosion and provide decision-making assistance to solve environmental problems. Southern Africa is affected by severe soil erosion, which has brought a series of development problems, such as food crises and poverty. This study used meteorological and remote sensing data, and the revised wind erosion equation model to explore the temporal and spatial dynamics of soil erosion in southern Africa from 1991 to 2015. The impact of climate dynamics on soil wind erosion was also analyzed. The results showed that wind erosion fluctuated during the study period, and it first showed a downward trend and then stabilized at a relatively low level after 2010. Soil wind erosion across 66.65% of the study area significantly decreased (p < 0.05) and near-surface wind speed was the most important factor. The change in wind speed had a positive impact on soil wind erosion across 68.18% of the area. Temperature and precipitation were significantly related to soil wind erosion over 18.96% and 24.63% of the area, respectively. Both can also indirectly affect soil wind erosion through their effects on vegetation cover. This study will help decision-makers to evaluate areas that are at high-risk from soil erosion in southern Africa and enable them to effectively protect fragile ecosystems.

Soil salinization seriously affects the movement of water in soil which then affects soil stability and sustainability in industrial and agricultural development. Fly ash, one of the most discarded solid wastes from coal-fired power plants, has been widely used as a recycled resource in recent years. The basic components of soda soil have been investigated through laboratory experiments. Soda soil samples with different amounts of fly ash are tested to study the changes in the characteristics of the material due to changes in water content and evaporation rate during drying. Changes in fractal and crack intensity factor are calculated based on digital image processing technology. The results show that the residual water content of soda soil increases from 8.55% to 16.22% with increases in the fly ash content. Fly ash can improve the water retention capability of soda soil, with a rate of increase of 89.68%. The average length of the surface cracks gradually decreases with increase in fly ash content, which indicates that fly ash can effectively inhibit the development of surface cracking in soil. The rate of cracking is an important measure for characterizing the development of cracks by measuring the area of the cracks. The crack area gradually decreases with increase in the fly ash content with different rates of cracking. The rate of cracking with a fly ash content of 10% is relatively slow, which indicates that 10% fly ash can effectively reduce cracking in soda soil thus resulting in a high residual water content.

Forward and reverse successions of karst rocky desertification (KRD) occur simultaneously, and are linked to human activity, thus presenting a mutual feedback loop. Previous studies have focused on the unilateral human-driven mechanism of KRD or the impact of KRD on social-economic activities. These lack quantitative measurement and in-depth understanding of interactions involved. Therefore, this study builds and applies a novel model for measuring the coupling relationship and degree between KRD and social-economic activity in the Guizhou karst region of China. Results show an overall improvement but local deteriorations in KRD from 2000 to 2011; conversely, social-economic activity intensities increased during that time period. With their spatio-temporal variations, positive and negative human–desertification coupling relationships with an increased coupling degree are found. Different coupling relationship types between KRD and social-economic development, including urbanization, economic development and household income, are shown. KRD is found to be high positively coupled with specific human behavior intensities such as population movement, steep slope cultivation and ecological restoration. An inverted U-shaped curve is observed in the coupling index of KRD and urbanization within different development levels. Negative coupling at a low urbanization level indicates the limitation of the karst physical environment on social-economic development. Positive coupling with increasing urbanization implies a conflict between environment protection and social-economic development. A return to negative coupling in several counties with high urbanization levels indicates a win-win for ecology and economy. The effectiveness of the proposed coupling model is demonstrated, informing differentiated strategies for combating KRD and improving social-economic development.