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.
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.
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.
We live challenging times on several levels, and in this context the second encyclical, Laudato Si’ (LS), of Pope Francis, published in 2015, has provided a special challenge for academics. As Pope Francis suggested in 2015, societies are challenged to modify the paradigms of life to achieve more sustainable development. LS has quickly become a widely quoted document, even by academics. This paper is the first bibliometric research about LS aiming to analyze this encyclical and explore several works published about LS between 2015 and 2020.To this end, we studied all documents published in the Web of Science Core Collection (238) and Scopus (222) about the topic “Laudato Si” in depth and analyzed them using bibliometric methods. The results show that there are scientific fields focused on studying LS in particular, namely Religious Sciences and the fields of Sustainability and Environment Studies. We also observed a small amount of networking among the authors publishing about LS.
Land-use practice shift in the wetland riparian zone can influence groundwater table (GWT) fluctuations and salts dynamics, potentially leading to soil salinization. The risk of soil salinization linked with high water tables could better manage using high growing capacity and deep-rooted phreatophytic vegetation via ‘biodrainage’ approach. We evaluated the impacts of short rotation willow (SRW) plantation on soil and groundwater salinity linked to shallow GWT fluctuations and compared with adjacent annual crop (AC) and pasture (PA) in a field experiment. Groundwater salinity (ECgw) along with depth to GWT and soil salinity (ECsoil at 0-60 cm depth) were measured along transects within each land-use practice in two prairie pothole region (PPR) wetland sites (A and B). The variations in ECgw were significant (p < 0.05) across land-uses; however, inconsistent between sites. The positive correlation with ECgw, ECsoil, and total dissolved salts (TDS) indicated higher salinity and salt accumulation with increased depth to GWT in both sites. The ECsoil varied significantly (p < 0.05) among land-use practices; however, no consistent land-use patterns were observed between sites. Throughout the experimentation, site B consistently exhibited higher ECsoil (two-fold) than site A. Decreasing inclinations were observed in ECsoil with increasing SRW biomass at both depths (i.e., 0-30 and 30-60 cm) and vice versa. This study refines our knowledge of SRW linked potential hydrological alteration and its implication on salinity, which provides critical context for degraded marginal riparian wetland soil management in the PPR.
Inadequate pasture management causes land degradation and negative impacts on the socio-economic development of agricultural regions. Given the importance for Brazil and the World of pasture-based livestock production, the recognition of pasture degradation is essential. The use of remote sensing satellite systems to detect degraded pastures increased in the recent past, because of their capability to survey large portions of Earth’s surface. A struggle nowadays is to improve detection accuracy and to implement high-resolution surveys at farmland scale using unmanned aerial vehicles (UAVs). The satellite sensors capture reflectance from the visible spectrum and near infrared bands, which allows estimating plant’s vigor vegetation indices. The NDVI is a widely accepted index, but to generate an NDVI map using a UAV a relatively high-cost multispectral sensor is required, while most UAVs are equipped with low-cost RGB cameras. In the present study, a script developed on the Google Earth Engine image-processing platform manipulated images from the Landsat 8 satellite, and compared the performances of NDVI and an improved color index that we coined “Total Brightness Quotient” of red (TBQR), green (TBQG) and blue (TBQB) bands. An efficient detection of pasture degradation using the TBQs would be a good prognosis for the surveys at farm scale where environmental authorities are progressively using UAVs and forcing landowners towards pasture restoration. When compared to NDVI, the TBQG showed a correlation of 0.965 and an accuracy of 88.63%. Thus, the TBQG proved as efficient as the NDVI in the diagnosis of degraded pastures.
Exploring the driving factors of ecosystem services (ESs) trade-offs/synergies is crucial for ecosystem management, especially in ecological conservation red line (ECRL) areas that maintain regional and national ecological security. Soil conservation (SC), water yield (WY) and carbon sequestration (CS) were simulated in the Beijing ECRL areas. Geographical weighted regression was used to explore the trade-offs/synergies, and the geographical detector was applied to quantitatively identify their driving factors. Results show that (1) the SC and CS show marked synergy which characterized more than 80% of each ECRL area; the proportion of the space area of trade-off and synergy between SC and WY, and WY and CS was roughly 3 to 7 and 4 to 6 in each ECRL area, respectively. (2) The synergy of the three pairs of ESs was most sensitive to terrain factors. The precipitation erodibility of soil and its necessity for vegetation make it a determinant of the trade-off between SC and CS; temperature was the determinant in the trade-off between WY and CS, with an explanatory power of 32.8%; potential evapotranspiration was best able to explain the spatial distribution of the trade-off between SC and WY. (3) The interaction between precipitation and other factors had the greatest explanatory power on the spatial relationship between SC and WY. Precipitation and relief amplitude are the main interactive factors respectively affecting the spatial trade-off and synergy between SC and CS. The trade-off and synergy between WY and CS were most sensitive to the interaction between climate factors and terrain factors.
Restoration has now emerged as a global priority, with international initiatives such as the “UN Decade on Ecosystem Restoration (2021-2030)”. To fulfil the large-scale global restoration ambitions, an essential step is the monitoring of vegetation recovery after restoration interventions. The aim of this study was to evaluate the utility of remotely-sensed vegetation indices, Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), to monitor the rate of forest regeneration across a tropical forest restoration project area in Kibale National Park, Uganda. As a result, we observed non-linear patterns in NDVI and EVI across the first 25 years of recovery. Both NDVI and EVI increase for the first 10 years of forest regeneration. This “greening” phase could be used as the indicator of successful onset of forest recovery. In particular, the decline of elephant grass, which suppresses the natural regeneration of trees in our area, can be detected as an increase in NDVI. Primary forests differed from the 25-year-old regenerating forests based on the unique combination of low mean and low seasonal variation in EVI. Our results, therefore, suggest that the long-term success of forest restoration could be monitored by evaluating how closely the combination of mean, and degree of seasonal variation in EVI, resembles that observed in the primary forest.
Land degradation is one of the major global environmental issues that need serious attention. The land itself is a complex system regulating myriads of processes and perturbation in anyone these would certainly lead to the stimulation of land degradation. Among these, fly ash (FA) dumping is one of the common-practices, which has been adopted to overcome land-use disruption and other health hazards. However, this practice has become a driving factor for FA-induced land degradation. Therefore, in purview to tackle this issue, the present article is aimed to identify and suggest plausible sustainable practices to restore and manage FA contaminated sites. It preliminarily deals with the systematic exploration and identification of FA-based and associated contaminated lands via geospatial technology with a brief focus on monitoring its different contaminant profiles in the FA and soil systems. Moreover, the article emphasizes identifying the potential local plant species in the FA-contaminated regions to understand the local people’s demands. Following this, it would suggest the major sustainable approaches to expedite the restoration of FA contaminated lands along with the key highlights of their bottlenecks, while the ground implementation. Nevertheless, the article aimed to unravel the recommended prospects to address those bottlenecks to develop an efficient restoration enterprise during the Decade on Ecosystem Restoration (2021-2030).
Fly ash (FA) is the 80% of coal burnt by-product of thermal power plants (TPPs), its disposal in landfills causes environmental and health issues. The amount of FA production is increasing continuously to fulfil the worldwide energy for demand, which possibly never find a practically safe method for FA dumping. Its fine particle size disperses in the air and causes air pollution and water pollution is resulted due to slurry erosion from FA dumps and contamination by leachate. Health issues and environmental concerns due to fly ash landfills/dumpsites can be prohibited by covering with phytoaccumulator plant species. Limitations of plant growth in FA includes alkaline pH, contain metals such as Cr, Cd, As, Hg and Pd, toxic level of B, pozzolanic properties of FA and lack of microbial activity. Generally, the phytoremediation process is slow therefore, to accelerate the phytoremediation process FA require organic amendments and bio-fertilizers. This article focuses on the role of naturally occurring plants in stabilization of FA dumpsite and physiochemical changes in FA. This review summarises the different holistic approaches of rehabilitations of FA landfills and also compiles how to convert FA landfills into useful landfills for bioenergy productions. Utilization of organic matter and industrial waste has been proved to provide essential nutrients for plant establishment and heavy metal accumulation. The outcomes of this learning are beneficial for classifying site-specific ecological restoration of FA landfills through holistic approach.
Araucaria araucana is an iconic long-lived endangered tree species exclusively distributed in Southern Chile and Argentina. Araucaria forest ecosystems provide a myriad of ecosystem benefits to local aboriginal Mapuche-Pehuenche communities. Among the main current threats for Araucaria forests are the increasing frequency and severity of wildfires and overgrazing. This study evaluates the effect of uncontrolled livestock grazing on soil quality indicators linked to critical functions relevant to forest regeneration and ecosystem service provision. We also aim to determine a set of soil quality indicators that are sensitive enough to grazing pressure, so they are useful as early indicators of degradation or the effectiveness of restoration practices. This study evaluated twenty soil quality indicators in two contiguous degraded forest areas with contrasting grazing pressure. We observed a substantial shift in forest structure, a reduction in tree coverage on the overgrazed sites. Overgrazing has produced significant deterioration of most soil physical, chemical, and biological quality indicators making soil conditions less suitable for seed germination and sapling establishment. We also observed an alteration in C, N, and P biogeochemical pools. Besides, soil physical indicators alterations suggest changes in these soils' hydrological behavior, potentially reducing water storage, availability, and increasing runoff. We show that uncontrolled grazing in native protected areas degrades soils and forest health, restricting forest regeneration and potentially accelerating erosive processes. Our results emphasized the need for an improved conservation plan for these forests that systematically evaluates and monitors livestock grazing and all its direct and indirect effects, including soil quality.
Forest transition theory posits that socioeconomic development in a country or region may cause its forestland to shift from net loss to net gain. However, forest transition may also occur under various policies, resulting in forest gains in some regions but deforestation in other regions. We used the telecoupling framework to address this crucially important issue that has rarely been examined. Using time series satellite images and statistical yearbook data from 2000 to 2020, this study seeks to understand land use change patterns, the corresponding regional spillover effects, and driving forces behind such patterns in Zhejiang Province, China. The results show that large-scale continuous deforestation has taken place since 2000, causing a total loss of forestland by 186,014 ha. In parallel with this forest loss and a slight decrease in arable land, urban construction land has soared by 169.45%. We found that developed municipalities such as Hangzhou witnessed increases in urban land at the expense of large-scale deforestation in underdeveloped municipalities such as Lishui. We believe that this cross-region land change pattern may arise from the Balance of Arable Land System (BALS) policy that seeks to achieve a goal of no net loss of cropland. Whatever land use policy—such as the BALS policy—must strike a good balance between competitive land uses that have different objectives such as residents’ living, ecology, and production. In addition to enriching the forest transition theory, this study provides a solid basis for future land use decisions in developing regions or countries.
A four-year field experiment was carried out to evaluate an integrated use of saline water for the saline soil reclamation in Hebei Province of North China. A landscape shrub (Caryopteris × clandonensis ‘Worcester Gold’) was cultivated using drip irrigation scheduled by rootzone soil matric potential control at five levels of water salinity (ECi): 0.8, 3.1, 4.7, 6.3, and 7.8 dS·m−1. Soil matric potential control was applied using a threshold of −5, −10, −15, and −20 kPa in the first, second, third, and fourth year, respectively. After four growing seasons, the saline soil (initial ECe value of 27.8 dS·m−1) was reclaimed to slightly saline soil for 0–1 m depth (4.1–7.2 dS·m−1) under drip irrigation with saline water of ECi < 7.8 dS·m−1. The salt leaching efficiency of root zone soil was highest in the first year and lowered year-by-year. The plants strongly responded to the different soil water and salinity regime. Significant decreases in survival rate, plant growth, and shoot dry weight in response to increasing ECi were found. To achieve a relative survival rate of >50%, the threshold salinity of irrigation water for ‘Worcester Gold’ cultivation was 7.8, 7.0, 5.6, and 5.3 dS·m–1, for the first, second, third, and fourth growing season, respectively. It is recommended to use an inter-seasonal evolving matric potential threshold of −10 kPa for dry season of the third year, −15 kPa for rainy season of the third year and dry season of the fourth year, and −20 kPa for rainy season of the fourth year.
Sustainable agronomic practices are tried all over the world to promote safe and eco-friendly crop production. Therefore, in the present study, the effect of seed endophytic bacteria and its consortia on soil biochemical property, soil nutrient, and yield of chickpea (Cicer arietinum L.) under field and pot conditions are investigated. Both the experimental results proved a significant increase in total soil organic carbon (OC), electric conductivity (EC), organic matter (OM), soil nutrient like available N, P and K content and important soil enzymes like dehydrogenase (DHA), beta glucosidase, alkaline phosphate, and urease was observed under the Enterobacter hormaechei BHUJPCS-15 (T1), Enterobacter cloacae BHUJPCS-21 (T2) and combined T3 (consortia of T1 and T2) treatments. Similarly, a significant increase in the grain yield (27-45% and 57-73%) in microbial treatment was found in pot and field experiments, respectively than control. In addition, whereas the higher plant biomass (14-38% and 42-78%) was recorded in the treated plant over the control plant. Similarly, the plant photosynthetic pigment (Chl a, b, total Chl) were also increased in the microbial treated plant than the control untreated chickpea plant. Our present study highlights the significance of sustainable agronomic practices for improving the soil quality and agricultural yield while reducing adverse impacts of chemicals by the use of seed endophytic microbes and their consortia.