Soil Restoration Research Articles

Reclamation of chromium-contaminated soil by native Cr(VI)-reducing and PHA-accumulating Bacillus aryabhattai CTSI-07.

Reclamation of chromium-contaminated soil by bacteria is a big confront concerning to soil health restoration, food safety, and environmental protection. Herein, the chromium-resistant Bacillus aryabhattai CTSI-07 (MG757377) showed resistance to 1000 and 300 ppm of Cr(VI) in nutrient rich Luria Bertani (LB) and nutrient-deficient sucrose low phosphate (SLP) medium, respectively. It reduced 96.7% of Cr(VI) from contaminated soil in the presence of 100 ppm of Mg within 96 h under optimized conditions. Furthermore, Cr(VI) reduction by the bacteria was validated by Fourier transform infrared spectroscopic (FTIR) and X-ray diffraction (XRD) analysis. Besides Cr(VI) reduction, the bacterial strain also showed plant growth promoting traits like N2 fixation and indole acetic acid (IAA) production. On the other hand, transmission electron microscopy (TEM) imaging confirmed polyhydroxyalkanoates' (PHAs) granule accumulation and 0.5 g/l of PHAs was extracted from bacterial cell using SLP medium. Infra-red (IR) spectra and proton nuclear magnetic resonance (1H NMR) chemical shift patterns established the PHAs as polyhydroxybutyrate (PHB). Melting (Tm) and thermal degradation (Td) temperature of the PHB were 169 °C and 275 °C, respectively, as evident from thermogravimetry differential thermal analysis (TG-DTA). Atomic force microscopic (AFM) imaging depicted that the PHB film surface was rough and regular. Furthermore, the multi-metal-resistant, plant growth-promoting, and PHB-producing bacteria could reduce 99.82% of Cr(VI) from contaminated soil within 120 days in pot culture. Thus, it can be used for long-term reclamation of chromium-contaminated soil to restore soil health, provide food safety, and environmental protection.

Ecological State of Haplic Chernozem after Pollution by Oil at Different Levels and Remediation by Biochar

One of the most modern and effective methods of soil restoration after pollution is the use of bioremediation. In recent years, special attention has been paid to the use of biochar. However, the ecological state after the introduction of biochar into petroleum-hydrocarbons-contaminated soils at different levels of pollution has been little studied. The work objective was to study the effect of biochar (10% of the soil mass) on the ecological statement of Haplic Chernozem contaminated with different levels of oil, from 0.1 to 50% of the soil mass. To assess the state of Haplic Chernozem after remediation with biochar, indicators of the biological activity of soils were studied. The maximum information content in the case of oil pollution and remediation with biochar was established by the activity of dehydrogenases (r = −0.90) and the total number of bacteria (r = −0.98). When applying biochar, the maximum stimulations of the integral indicator of the biological state (IIBS) relative to the background, by 62, 76, and 72%, were noted in samples with oil at concentrations of 0.5, 25, and 50%, respectively. The results of the study should be used for biodiagnostics and monitoring of the state of oil-contaminated Haplic Chernozem at different levels of contamination after remediation with biochar.

Amelioration of a saline‐alkaline soil using biochar and compost: Impacts on plant growth, soil biological and chemical characteristics

AbstractLand degradation reduces productivity and biodiversity, and requires restoration of both soil condition and vegetation to re‐establish ecosystem services. Organic amendments can improve soil biological and chemical properties, thereby enhancing revegetation success in severely degraded soil. This study investigated the use of compost and biochar to support revegetation and soil restoration. Soil was collected from a severely degraded creek bed in an agricultural farm in south‐western Australia (UWA Farm Ridgefield) and amended with compost (2.5% and 5%) and biochar (5% and 10%), both alone and in all pairwise combinations. Saltbush (Atriplex nummularia) seedlings were grown for 10 weeks in glasshouse conditions. Following harvest, plant growth and soil chemical properties were analysed. DNA was extracted from rhizosphere soil for bacterial diversity profiling with subsequent putative functional genes relating to carbon, nitrogen and phosphorus cycling using an in‐silico approach. Compost improved growth of root and shoot biomass. Both compost and biochar improved the alkaline soil by reducing pH and increasing nitrate, phosphorus and potassium levels. Compost addition also had a significant effect on rhizosphere bacterial community structure, decreasing alpha diversity and altering beta diversity indices. Amendment of soil also changed the relative abundance of putative nutrient cycling genes, with an increase in the potential for denitrification, carbon and phosphorus cycling and a decrease in ammonification potential. Application of this compost‐biochar combination improved plant growth and soil condition by altering both chemical and biological characteristics of the soil, and therefore may provide an effective management strategy for supporting restoration in a degraded landscape.

High-Resolution Soil Moisture Measurements in Rational Fertilization and Irrigation Methods as Part of the Sustainable use and Management of Soil Under Climate Change - DIY Solutions

Current climate changes, including drought, represent one of the most severe and extreme natural phenomena, directly affecting the environment, economy and society, and increasingly leading to soil degradation. In drought-stricken areas, losses in agricultural production are driving up food prices. The world's demand for water will continue to grow further in the coming decades. In view of the presented facts, there is a tremendous need for a systemic approach to saving water in the process of soil reclamation and conducting multidisciplinary research in this field. The problem of fertilization is linked to reasonable irrigation. These processes ought to be synchronized and run simultaneously, under the control by the system. This paper presents a prototype measurement probe as an element of a measurement network and the results of tests of its application in under use. The purpose of this research was testing a cheap DIY to solution identify the availability of water resources in the soil layer where the major plant root mass is found, i.e., to a depth of up to 110 cm, and to rationalize the management and improve the efficiency of water use during irrigation, as well as to monitor the migration of water in the soil in the era of climate change. The conducted tests have yielded concrete conclusions - current climate change is already resulting in unusual situations, including the different behaviour of water migrating through the soil. Considering that a wide variety of soils and geological systems are present, it is extremely important to understand these mechanisms in great detail, which makes the created solution feasible. Such a detailed analysis of water migration in soil under use can very successfully support, for example, a low-cost precision irrigation (preventing drought), or fertilization, indicating periods when and where to introduce nutrients after rainfall so that they naturally reach the depth of the largest root mass as quickly as possible. The DIY solution can be crucial in Third World countries by conducting at least single, cheap soil moisture measurements, and in many other places affected by the problem of water deficit, it can be an alternative to extend existing monitoring systems.

Forty years of soil research funded by the European Commission: Trends and future. A systematic review of research projects

AbstractThe European Green Deal with its high ambition has set the European Union (EU) on a promising path towards greater soil protection. The EU Soil Strategy 2030, the Biodiversity Strategy 2030, the Farm to Fork Strategy, the Zero Pollution, the Nature Restoration Law and the European Climate Law, among others, include actions to protect our soils. Research and Innovation (R&I) will play a key role in developing new knowledge and tools enabling the transition to healthy soils. The main aim of this paper is to analyse past and near‐future trends in EU's funding for R&I on soil‐related issues. For this purpose, a review of EU‐funded soil projects was conducted based on the data available in the Community Research and Development Information Service and the official portal for European data. Our analysis shows that over the past 40 years, the EU has invested significantly in developing integrated knowledge about the relationships between soil functions and ecosystem services and how human‐induced pressures affect soil health. Following the adoption of the EU Soil Thematic Strategy in 2006, there was an increase in research funding for soil‐related research. Furthermore, our analysis also illustrates an interesting interplay of permanent and changing soil themes. The Horizon Europe Mission ‘A Soil Deal for Europe’, which aims to establish a network of 100 living labs and lighthouses to lead the transition towards healthy soils and safeguard human and planetary health by 2030, provides a further incentive for soil research. Together with the EU Soil Strategy 2030 and the new proposal for a Directive on Soil Monitoring and Resilience (Soil Monitoring Law), and the EU Soil Observatory (EUSO), the three instruments set up the political framework, concrete measures, and a monitoring system needed for the protection, restoration and sustainable use of soils.

Soil Contaminants and Their Removal through Surfactant-Enhanced Soil Remediation: A Comprehensive Review

This review provides a comprehensive analysis of the effectiveness of surfactants in enhancing the remediation of contaminated soils. The study examines recent and older research on the use of effluent treatment techniques combined with synthetic surface-active agents, bio-surfactants, and various categories of surfactants for soil reclamation purposes. The main purpose of this review is to evaluate the effectiveness of surfactants in enhancing the remediation of contaminated soils. The research question is to explore the mechanisms through which surfactants enhance soil remediation and to assess the potential benefits and limitations of surfactant-based remediation methods. This review was conducted through an extensive literature search of relevant articles published in scientific databases. The articles were selected based on their relevance to the topic and their methodological rigor. Types of possible soil pollutants and the requirements of specific surfactants were discussed. Structural relationships between pollutant and surfactants were described thoroughly. Extensive study revealed that surfactants have shown great potential in enhancing the remediation of contaminated soils. Surfactants can improve the solubility and mobility of hydrophobic contaminants and facilitate their removal from soil. However, the effectiveness of surfactant-based remediation methods depends on several factors, including the type of contaminant, the soil properties, and the surfactant concentration and type. Surfactant-enhanced soil remediation can be an effective and sustainable method for addressing soil contamination. However, the optimal conditions for using surfactants depend on the specific site characteristics and contaminant properties, and further research is needed to optimize the use of surfactants in soil remediation.

Environmental Sustainability through Soil Conservation: An Imperative for Future Generations

Environmental sustainability is a critical concern for the well-being of future generations. Within the realm of sustainability, soil conservation plays a crucial role in preserving Earth's vital resource and maintaining the balance of ecosystems and agricultural productivity. This review explores the importance of environmental sustainability and the significance of soil conservation in achieving this objective. It examines the detrimental impacts of soil degradation on ecosystems and agriculture, emphasizing the need for effective conservation strategies. Various strategies for soil conservation and sustainable land management are discussed, including erosion control, soil restoration, agroforestry, and precision agriculture. The review also highlights the benefits and challenges associated with implementing soil conservation measures. By embracing these strategies, we can ensure the long-term health and productivity of our planet's soil, securing a sustainable future for generations to come.

Restoration of soils contaminated with PAHs by the mixture of zeolite composites mixed with exogenous organic matter and mineral salts

The major cause of soil degradation (contamination, erosion, compaction) is closely linked to agriculture, i.e., unsustainable agriculture practices, which are reflected in the depletion of the soil organic carbon pool, loss in soil biodiversity, and reduction of C sink capacity in soils. Therefore, the agricultural practice of applying carbon-rich materials into the soil is an attractive solution for climate change mitigation and soil ecosystem sustainability. The paper aimed to evaluate the effectiveness of the addition of organic-mineral mixtures to the mineral salts (NPK), including the exogenous organic matter (lignite) mixed with zeolite-carbon (NaX-C) or zeolite-vermiculite (NaX-Ver) composites in the restoration of soils contaminated with PAHs. The addition of zeolite composites to fertilizer resulted in a significant reduction in soil PAH levels and a corresponding reduction in plant tissue content, without compromising yields, compared to the control and separate application of NPK. A Significant correlation between PAHs and pHH2O, pHKCl, EC and dehydrogenase activity (DhA) was found in soils. The addition of zeolite composites with lignite significantly reduced the content of PAHs in straws, especially following the application of NaX-C. However, in the case of grains, the highest percentage reduction in comparison to NPK was observed for the highest dose of NaX-Ver.

Legal aspects of state land monitoring in the context of carrying out cadastral activities

In the article a scientific study was conducted and, based on it, conclusions were formulated regarding the legal nature and features of state land monitoring in the context of cadastral activity, specific features of its components such as land monitoring, soil monitoring, land relations monitoring and land market monitoring were identified, and proposals were substantiated regarding the improvement of legislation in this area, in particular in the conditions of martial law in Ukraine.It is proposed to use the term «state land monitoring» in the science of land law of Ukraine. Implementation of state land monitoring is one of the important functions of state regulation of land relations. The author proposes to understand state land monitoring as a complex system of observation, analysis, collection, preservation, generalization and publication of information about the condition of lands and soils, about changes in indicators of the qualitative condition of soils and their fertility, about the ownership, use and disposal of land plots, in particular about the price (value) of land plots, real rights to them and the amount of the payment for land, which is carried out with the aim of timely detection of changes in the condition of lands and soils, their evaluation, prevention and elimination of the consequences of negative processes, as well as ensuring transparency of land relations and public access to information about the condition these relations. State land monitoring includes: land monitoring; soil monitoring; monitoring of land relations; land market monitoring.The military aggression of the Russian Federation against Ukraine caused extreme damage to the environment, including the soil. The article proposes to develop and approve a special procedure for monitoring lands, agro-landscapes and soils affected by the armed aggression of the Russian Federation against Ukraine. The collected, summarized and analyzed information based on the results of the indicated monitoring will be the basis for making decisions regarding the specifics of conservation or reclamation of such lands depending on the type of pollution and the approval of the National Program for the Restoration of Lands and Soils of Ukraine in the post-war period.

Organic Amendments promote saline-alkali soil desalinization and enhance maize growth.

Secondary soil salinization in arid and semi-arid regions is a serious problem that severely hampers local agricultural productivity and poses a threat to the long-term sustainability of food production. the utilization of organic soil amendments presents a promising approach to mitigate yield losses and promote sustainable agricultural production in saline-alkali soil. In this study, we established four distinct treatments, chemical fertilizer (CK), humic acid with chemical fertilizer (HA), carboxymethyl cellulose with chemical fertilizer (CMC), and amino acid with chemical fertilizer (AA), to elucidate their respective impacts on the reclamation of saline soil and the growth of maize. The findings of our study reveal notable variations in desalination rates within the 0-40 cm soil layer due to the application of distinct soil amendments, ranging from 11.66% to 37.17%. Moreover, application of amendments significantly increased the percentage of soil macro-aggregates as compared to the CK treatment. Furthermore, HA and AA treatments significantly augmented soil nutrient content (HA: 48.07%; AA: 39.50%), net photosynthetic rate (HA: 12.68%; AA: 13.94%), intercellular CO2 concentration (HA: 57.20%; AA: 35.93%) and maize yield (HA:18.32%; AA:16.81%). Correlation analysis and structural equation modeling unveiled diverse mechanisms of yield enhancement for HA, CMC, and AA treatments. HA enhanced yield by increasing organic matter and promoting soil aggregate formation, CMC improved soil water content and facilitated salt leaching due to its excellent water-holding properties, while AA increased yield by elevating soil organic matter and effective nitrogen content. Among the array of soil amendment materials scrutinized, HA treatment emerged as the most promising agent for enhancing soil conditions and is thus recommended as the preferred choice for treating local saline soils.

Sustaining soil health and tomato production through organic inputs and bacterial inoculations in alluvial soils detoxifying plant contaminants

The demand for organic tomatoes is gaining momentum globally, especially for their nutritional quality, shelf-life, and yield sustainability. Similarly, the restoration of metal-contaminated soils and maintenance of soil health is getting momentum through the application of organic inputs and microbial inoculations in soils. The present study evaluates different concentrated organic inputs and biofertilizers with a minimal dosage (14.3% of the recommended dose of fertilizers or RDF) under a field experiment conducted at the Agricultural Farm of Amity Institute of Organic Agriculture, Amity University, Noida, Uttar Pradesh, India. Organic treatments included mustard cake, goat manure, poultry manure, farmyard manure (FYM), neem cake, and biofertilizers (Azotobacter and phosphate solubilizing bacteria, or PSB). FYM (15 t ha−1) and vermicompost (VC 3.0 t ha−1) (T5), and the optimized inputs (containing the dual inoculation of Azotobacter and PSB, a mixture of organic inputs, and 14.3% RDF (T11) significantly improved plant height, number of branches/leaves/fruits, carotenoids, lycopene, fruit weight, yield, ascorbate peroxidase, total antioxidants, superoxide dismutase, total soluble solids (TSS), Vitamin C, and shelf-life in tomatoes. Organic inputs and inoculation of Azotobacter and PSB significantly reduced the concentration of Cd, Cr, and Pb from soils. The authors conclude that (a) the combined application of FYM and VC, and (b) the optimized mixture of bulky and concentrated organic inputs, 14.3% RDF, and the dual inoculation can improve the nutritional quality, minimize heavy metals (Cd, Cr, and Pb), and overall, sustain tomato production in the hot semi-arid alluvial sandy loam soils. The optimized organic inputs with dual microbial inoculations harness the climatic conditions in tropical regions to facilitate better color and ripening, and other quality parameters leading to higher lycopene contents in tomatoes.

Distinct adaptive strategies and microbial interactions of soil viruses under different metal(loid) contaminations

Viruses, as the most abundant organisms, significantly influence ecological function and microbial survival in soils, yet little was known about how viruses and virus-microbe interactions respond to environmental stresses induced by metal(loid) contaminations. Here, we conducted the metagenomic analysis to investigate the adaptative mechanisms of soil viruses under different metal(loid) contamination levels. By capturing a catalogue of 23,066 viruses, we found that viral communities exhibited the increased richness, diversity, and the temperate to lytic ratio in facing the highest metal(loid) contaminations. Meanwhile, viruses displayed obvious lineage-specific infection modes to distinct dominant hosts under different pollution levels. Viral functions linking to the inhibition of transcription and the enhancement of DNA repairment as well as multiple resistance not only contributed to coping with elevated multiple metal(loid) stresses, but also facilitated the adaptation and functioning of viral hosts. Moreover, the harmonious coexistence of viruses and resistant/pathogenic bacteria under the heaviest contaminations potentially exacerbated disseminating resistance and pathogenicity, while viruses under the lightest contaminations might be natural predators of resistant/pathogenic bacteria through lysing host cells. Overall, this study highlights the ecological importance of viral adaptation and the interactions between viruses and resistant/pathogenic bacteria in contaminated environments, contributing to developing virus-based approaches to soil restoration.

The Impact Of Asphalt Material And Soil Salinity On Crop Growth Of Sunflower

The sunflower represents a significant economic annual plant (oilproducing and edible). Even though the sunflower is categorized as one of the most salt-tolerant plant types and is treated as a significant plant in saline soil reclamation, the rate of its photosynthetic and growth are adversely influenced by high levels of salt in the soil, significantly when the groundwater level rises on the soil surface, which in turn causes the raising of soil salinity. Therefore, there is a critical need to control salt accumulation to increase sunflower crop yields. An evaluation of the impact of asphalt material, soil salinity, groundwater table depth, and soluble ions on the growth of sunflower crops is presented in this paper. Several treatments were used in this study: asphalt material, bitumen material, and controlling treatment. The experiments were conducted, calibrated, and validated during the season of spring 2019. The results show a considerable reduction in soil salinity and groundwater table depth regarding the asphalt material control aspect, thus increasing the growth properties of the sunflower crops. Keywords: Growth of Sunflower, Asphalt and Bitumen Materials, Soil Salinity, Soluble Ions, Groundwater Table Depth.

Amelioration of saline‐alkali land by cultivating Melia azedarach and characterization of underlying mechanisms via metabolome analysis

AbstractSoil salinization is a serious problem leading to ecological degradation. Melia azedarach is highly salt‐tolerant, and its application to saline‐alkali land is a promising strategy for restoring degraded lands. However, most studies only focus on the salt‐reducing effect of herbs on saline‐alkali land, and there are few studies on the metabolic adaptation mechanism of trees in the process of soil restoration in coastal saline‐alkali land. In this study, we analyzed the soil properties and metabolome of M. azedarach roots grown in low‐ (<3 g/kg; L), medium‐ (5 ~ 8 g/kg; M), and high‐ (>10 g/kg; H) salinity soils to explore the amelioration effect and adaptation mechanism of M. azedarach to soils with differential salinity. Cultivation of M. azedarach was associated with a decrease in the concentration of Na+ and increases in organic matter content and alkaline phosphatase and urease activities in the rhizosphere soil. The metabolome analysis revealed that a total of 382 (ESI+) and 277 (ESI−) differential metabolites (DEMs) were detected. The number of DEMs in roots rose with increased soil salinity, such as sugars and flavonoids in H versus L, and amino acids in M versus L. The most up‐regulated DEMs were 13‐S‐hydroxyoctadecadienoic acid, 2′‐Deoxyuridine, and 20‐hydroxyleukotriene B4. Combined analysis of soil properties and M. azedarach DEMs indicated that alkaline phosphatase activity was positively correlated with traumatic acid concentration. Taken together, these results indicate that M. azedarach has the potential to reduce soil salinity and enhance soil enzyme activity, and it can adapt to salt stress by regulating metabolites like sugars, amino acids, and flavonoids. This study provides a basis for understanding the mechanism underlying the adaptation of M. azedarach to saline‐alkali soil and its amelioration.

Functional and biotechnological potential of microbiome associated with soils colonised by cyanobacteria in drylands

Drylands are areas under continuous degradation and desertification frequently covered by cyanobacterial biocrusts. Several studies have indicated that soil microorganisms contribute to nutrient cycling. Nevertheless, little is still known about how those could potentially be participating according to their taxonomic groups. In addition, biocrust-associated communities still remain largely unexplored at taxonomic and functional levels and, therefore, biotechnologically underexploited in comparison with other terrestrial ecosystems. This work aimed at revealing the ecological and biotechnological potential of soil communities using a shotgun sequencing approach in cyanobacterial-colonised biocrusts in the Tabernas Desert regarding the cycles of carbon, nitrogen, phosphorus, iron, sulfur, and potassium. The abundance and successful adaptation of major groups Rubrobacter and Conexibacter was explained by the presence of metabolic diversity regarding glycolytic and CO2 fixation pathways but also by exhibiting a rich pool of hydrolytic enzymes. Besides, Rubrobacter representatives might potentially be driving sulfate mineralisation. Others, such as Caulobacter representatives, were also suggested to have a potential key role in K+ uptake. Furthermore, iron uptake was found to potentially be mediated via synthesis and release of siderophores, mostly derived from pseudomonads. Importantly, this work revealed a meaningful biotechnological niche in which the recovery of novel isolates is a very desirable step forward for the industry and a step forward in unwrapping the potential role of those microorganisms in soil restoration as well as in the functioning of arid soils as CO2 sinks.

Soilization utilization of solid waste: Ecological regulation of phosphorus tailings-based soil with physicochemical improvement and Bacillus_cereus-addition

Extraction and utilization of effective phosphorus from solid waste have been an important approach for alleviating phosphorus resource shortage. The extraction of available phosphorus by microbial method with low cost, mild conditions and simple process has been drawing attention from the majority of research scholars. However, relevant studies on special microbial communities for effective phosphorus extraction from solid waste are less. In this work，a functional Bacillus_cereus strain screened from phosphate tailings, phosphate ore and forest rhizosphere soil was inoculated into phosphate tailings (PT), modified phosphate tailings (IS) and highland red soil (SS). Compared with SS, the water-holding properties, fertility, leaching toxicity and microbial community diversity of PT and IS with and without bacteria were analyzed. PT+, SS+ and IS+ (after adding bacteria to PT, SS and IS) showed moderately alkaline pH, and the available phosphorus content enhanced by 31.73%, 20.05% and 39.41% respectively. The leaching toxicity phosphate of PT+ and IS + decreased by 4.89 mg/kg and 2.61 mg/kg respectively, while that of SS + increased by 5.45 mg/kg, indicating differences in the phosphorus solubilization mechanism of Bacillus_cereus for different soils. Furthermore, the modification and bacteria treatment improved the relative abundance of Pedobacter, Alcaligenaceae and Pseudomonas, thus enhancing the phosphorus solubility of the PT bacterial community. This work may achieve efficient utilization and ecological restoration of phosphorus tailings-based soil and contribute to long-term sustainable agricultural development.

Metagenomics and proteomics profiling of extracellular polymeric substances from municipal waste sludge and their application for soil and water bioremediation

This study assessed the components of anaerobically digested sludge, activated sludge, and microbial and extracellular polymeric substance (EPS) enzymes to identify the mechanisms underlying nitrogen removal and soil regeneration. 16S rRNA gene amplicon-based sequencing was used to determine the microbial community composition and the related National Center for Biotechnology Information (NCBI) protein database was used to construct a conventional library from the observed community. EPS components were identified using gel-free proteomic (Liquid Chromatography with tandem mass spectrometry-LC/MS/MS) methods. Alginate-like EPS from aerobically activated sludge have strong potential for soil aggregation and water-holding capacity, whereas total EPS from anaerobic sludge have significant potential for ammonia removal under salt stress. Fourier transform infrared spectroscopy (FTIR) revealed that both EPS may contain proteins, carbohydrates, humic compounds, uronic acid, and DNA and determined the presence of O–H, N–H, C–N, CO, and C–H functional groups. These results demonstrate that the overall enzyme activity may be inactivated at 30 g L-1 of salinity. An annotation found in Kyoto Encyclopedia of Genes and Genomes (KEGG)- KEGG Automatic Annotation Server (KAAS) revealed that the top two metabolic activities in the EPS generated from the anaerobic sludge were methane and nitrogen metabolism. Therefore, we focused on the nitrogen metabolism reference map 00910. EPS from the anaerobically digested sludge exhibited nitrate reductase, nitrite reductase, and dehydrogenase activities. Assimilatory nitrate reduction, denitrification, nitrification, and anammox removed ammonia biochemically. The influence of microbial extracellular metabolites on water-holding capacity and soil aggregation was also investigated. The KAAS-KEGG annotation server was used to identify the main enzymes in the activated sludge-derived alginate-like extracellular EPS (ALE-EPS) samples. These include hydrolases, oxidoreductases, lyases, ligases, and transporters, which contribute to soil fertility and stability. This study improves our understanding of the overall microbial community structure and the associated biochemical processes, which are related to distinct functional genes or enzymes involved in nitrogen removal and soil aggregation. In contrast to conventional methods, microbial association with proteomics can be used to investigate ecological relationships, establishments, key player species, and microbial responses to environmental changes. Linking the metagenome to off-gel proteomics and bioinformatics solves the problem of analyzing metabolic pathways in complex environmental samples in a cost-effective manner.

Effects of saline water on soil properties and red radish growth in saline soil as a function of co-applying wood chips biochar with chemical fertilizers

BackgroundCurrently, using unconventional water sources in agriculture has become necessary to face overpopulation worldwide. Therefore, a pot experiment was carried out to evaluate the effects of irrigation with saline water in the presence of co-applied wood chips biochar (WCB) with chemical fertilizers on physicochemical properties and nutrient availability as well as growth parameters, and yield of red radish (Raphanus sativus L.) grown in the saline sandy soil.MethodsThe WCB was added to the saline sandy soil at levels of 0 (control), 2.5, and 5% w/w. Then, this soil was cultivated by red radish plants and irrigated with saline water (5 dS m− 1). This experiment was performed in a randomized complete block design with three replicates.ResultsCompared with the control treatment, WCB treatments increased significantly soil water holding capacity by 34.8% and 73.2% for levels of 2.5 and 5%, respectively. Soil pH decreased significantly in all WCB treatments. The relative increase in the total available nitrogen over the control was 30.1 and 103.5% for 2.5 and 5% wood chips biochar, respectively. Compared to the control, applying WCB at 2.5% led to an increase in the fresh root weight of red radish plants by 142.7%, while 5% caused a decrease in the fresh root weight of red radish plants by 29.4%.ConclusionRecently, WCB represents an interesting approach to the rehabilitation of saline soils and the management of using saline water sources. It is recommended that combined application of WCB at a level of 2.5% with chemical fertilizers in order to improve red radish growth and nutrient retention in the saline sandy soil which preserves the ecosystem as well as increases productivity leading to the reduction of costs.

The relation between mutualistic mycorrhiza and endophytic plant-fungus associations and their effect on host plants

Aim. A review of the literature to establish the mechanisms of the main mutualistic interactions that are important for the potential application of symbiotic fungi as biofertilizers, bioprotectors and bioregulators for more sustainable and so-called greening agriculture, soil restoration and understanding the role of microsymbionts in natural ecosystems. Methods. Comparative analysis of scientific literature. Results. Root mycorrhization is a potent factor of plant growth intensification, metabolic processes activation and macro-organism development improvement. Mycorrhiza formation is notable for angiosperms and gymnosperms, yet many representatives of bryophytes, ferns, and mosses also reveal (other) close symbiotic relations with fungi. Mycorrhizal fungi account for about 10 % of identified fungal species, including essentially all of the Glomeromycota and substantial fractions of the Ascomycota and Basidiomycota. De- pending on the fungal structures and microsymbiont position in tissues or cells of the macrosymbiont, arbuscular, ericoid, arbutoid, monotropoid, orchid mycorrhiza and so-called ectendomycorrhiza, and ectomycorrhiza are distinguished. This review gives an overview of the signalling interaction between partners and the bidirectional mechanism of nutrient exchange or other mutual benefits. Conclusions. Microscopic saprophytic fungi, capable of penetrating plant roots and playing a critical role in plant adaptation to abiotic and biotic stressors, are of special interest in mutualistic symbioses. In addition, while forming mutualistic symbioses with plants, the saprophytic fungi promote bio- mass increase and enhance the food traits of plants. The type of interaction depends on both micro- and macrosymbiot; it may in some cases and for some organisms fluctuate from mutualistic, commensalistic to antagonistic, even parasitic interactions, demonstrating different stages of mutualism evolution and co-habitation and/or evolution of plants and fungi. A better understanding of the diverse roles of symbiotic microorganisms in ecosystems will improve the ways of their application in agriculture.

Unexpected consequences of afforestation in degraded drylands: Divergent impacts on soil and vegetation

Forestry has long been considered an effective means of restoring degraded drylands worldwide. Often, afforestation in such lands relies on the establishment of runoff harvesting systems that are formed as contour bench terraces on hillslopes, increasing water availability for the planted trees and shrubs. The construction of terraces requires intensive earthworks by heavy machinery. This study assessed the long-term (>10 yrs) effects of forestry-related land-use change on soil properties and herbaceous vegetation in 16-year-old and 12-year-old afforestation sites (established in 2005 and 2009), and in nearby control (“natural”) areas in the semi-arid northern Negev, Israel. Mean herbaceous vegetation height in the 2005 afforestation sites (12.1 cm) was significantly (P = 0.0009) and 23% greater than in the control areas (9.8 cm), whereas in the 2009 afforestation sites (6.2 cm) it was 37% lesser than in the control areas. Mean herbaceous vegetation aboveground biomass was similar in the 2005 afforestation (0.39 Mg ha−1) and control areas (0.38 Mg ha−1), and almost significantly (P = 0.0510) and twofold greater than in the 2009 afforestation sites (0.19 Mg ha−1). The effect of hillslope aspect on these variables was substantial; their mean values were higher in the northern (mesic) hillslopes than in the southern (xeric) hillslopes. Soil samples were obtained from depths of 0–5 and 5–10 cm and physio-chemo-biological properties were assessed in the laboratory. The overall soil quality – as calculated by two soil quality indices (SQIs), including the generalized SQI (SQIgen) and the minimum dataset SQI (SQIMDS) – was significantly (P < 0.0001 for both indices) and 13–22% greater in the control areas (0.52 and 0.61, respectively) than that in the afforestation treatments (0.44–0.46 and 0.50–0.51, respectively). These results are generally attributed to the removal of soil's A-horizon during earthworks, and the exposure of the underlying B-horizon. The similar SQI values of both hillslope aspects, as well as of both soil depths, indicate the generally degraded state of the entire region. In conclusion, while contour bench terracing may facilitate the recovery of herbacaeous vegetation to some extent, the effectiveness of this practice for soil restoration is questionable. Overall, insights of this study demonstrate a caveat that converting natural drylands to forestry systems may not yield sufficient ecological benefits, and therefore should be implemented with caution.