Browsing by Author "Rahul Bhadouria"

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A critical review on the research trends and emerging technologies for arsenic decontamination from water
(Elsevier B.V., 2021) Pardeep Singh; Anwesha Borthakur; Rishikesh Singh; Rahul Bhadouria; Vipin Kumar Singh; Pooja Devi
To understand the current research output on arsenic (As) removal and research related to the As contamination, a bibliometric analysis based on Scopus database was carried out. The analysis includes the research covering the leading countries and year wise literature outputs. Bibliometric analysis revealed increasing trend in research published on As removal (more than 1200 articles) using physico-chemical methods during 1995 onwards and United States of America (USA) as leading contributor. Among different research institutions, Chinese Academy of Sciences has contributed maximally to research articles reaching up to 950 and maximum 635 research articles were published in the journal Environmental Science and Technology with respect to As removal using physico-chemical methods. With respect to As removal using biological methods, around 400 research articles were recorded during 1995 onwards and maximum article contribution (1052) was registered for China followed by USA (964). Based on Scopus data 2021, maximum 222 articles on As removal using biological methods were recorded for the journal ‘Chemosphere’. The present review emphasizes on currently available physico-chemical as well as emerging treatment processes for the removal of As, generally occurring as arsenite and arsenate, from drinking water. It has been suggested by various studies that a combination of low-cost physico-chemical treatment methodologies like ion exchange, reverse osmosis, precipitation, filtration and adsorption along with biological methods can be a safe alternative for As removal from drinking water. Overall, the study suggests that there is a strong need for further research on efficient processes involving lab to land approaches for As removal from groundwater in order to reduce the toxicity and contamination of As in drinking water. © 2021 Elsevier B.V.
Agriculture in the era of climate change: Consequences and effects
(Elsevier, 2019) Rahul Bhadouria; Rishikesh Singh; Vipin Kumar Singh; Anwesha Borthakur; Arif Ahamad; Gaurav Kumar; Pardeep Singh
The changing environmental conditions, especially global warming and climate variability, are major concerns and have an adverse impact over the future of agriculture. The changing climate has become a global issue which needs rapid policy development at national and international levels. The melting of massive Himalayan glaciers would considerably change the impact of temperature regimes which is necessary for blossoming of several crop plants. Thus, the current generation needs to find solutions to combat the negative impacts of environmental consequences on agricultural crops. Useful strategies include the conservation of the world’s huge biodiversity together with other natural resources. Modifications in currently used agricultural practices and the search for new plant species tolerant to different abiotic and biotic environmental stresses could help to mitigate the negative impact of climate change. © 2019 Elsevier Inc. All rights reserved.
Combined application of biochar and farmyard manure reduces wheat crop eco-physiological performance in a tropical dryland agro-ecosystem
(Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University, 2020) Rishikesh Singh; Pratap Srivastava; Rahul Bhadouria; Abhinav Yadav; Hema Singh; Akhilesh Singh Raghubanshi
Combined application of biochar and organic fertilizer has been widely recommended for improving soil bio-physical properties. However, detailed exploration of combined application on crop eco-physiological performance is limited. In this study, we explored the agronomic and eco-physiological responses of wheat crop grown under different combinations of rice-husk ash (RHA/biochar), farmyard manure (FYM) and chemical fertilizers in a silty loam soil. Aboveground biomass varied significantly across the treatments and was found higher (11–31%) under chemical fertilizer-applied treatments, but lower (6%) under sole RHA-applied treatment as compared to control. Crop eco-physiological parameters varied significantly (at P < 0.01) with the treatment and crop growth stages. Sole chemical fertilizer- and FYM-applied treatments showed better (5–26% higher), whereas sole RHA- and combined RHA + FYM-applied treatments showed poor (2–15% lower) photosynthetic rate as compared to control. Ear length was moderately correlated (r = 0.53) with aboveground biomass and explained 27% of the variability in it. Transpiration rate, intercellular CO2 concentration and water-use efficiency (WUEp) were identified as the major determinants of photosynthetic rate during vegetative and maturity growth stages. WUEp along with transpiration rate was found to explain 94% of the variability in photosynthetic rate for overall dataset. The findings suggest that combined RHA + FYM amendment may limit crop agronomic and eco-physiological performance due to nutrient immobilization. Therefore, combined application of RHA + FYM with chemical fertilizer application at reduced rate can be suggested for improving crop eco-physiological and agronomic responses under the sustainable agriculture practices in silty loam soils of tropical dryland agro-ecosystems. © 2020, The Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University.
Effect of Engineered Nanoparticles on Soil Attributes and Potential in Reclamation of Degraded Lands
(Springer Nature, 2021) Vipin Kumar Singh; Rishikesh Singh; Ajay Kumar; Rahul Bhadouria
Rapid upsurge in the discipline of nanoscience and technology has led to emergence of myriads of nanoparticles. Apart from substantial application in medicine, textile, food science, and environmental technology, nanoparticles have received considerable application and immense opportunities in agricultural practices. Given the inherent potential, nanoparticle based on zinc, iron, manganese, copper, titanium, and mixtures thereof has been successfully employed in agricultural lands. Although negative consequences of nanoparticle application are well recognized, the judicious application of various nanoparticles in agriculture could improve the soil productivity in a better way in contrast to currently used strategies. Therefore, assessment of soil attributes may provide important insight on possible threats of nanoparticles in agro-ecosystem. The modulation in characteristics like pH, moisture content, soil organic matter, nutrient and mineral composition, microbial attributes, fauna and enzymatic activities to a great extent after the introduction of nanoparticle in agroecosystem is documented. Unprecedented rise in agricultural technologies and accelerated application of agrochemicals are the important phenomena responsible for massive degradation of agricultural lands worldwide causing decline in crop productivity. Nanotechnology could provide important platform for efficient restoration of degraded land areas. This chapter has reviewed on application of engineered nanoparticles in (a) improving agricultural productivity, (b) important techniques for nanoparticle quantification, (c) impact on soil characteristics, and (d) potential in management of degraded lands. © 2021, Springer Nature Switzerland AG.
Effects of grass competition on tree seedlings growth under different light and nutrient availability conditions in tropical dry forests in India
(John Wiley and Sons Inc, 2020) Rahul Bhadouria; Pratap Srivastava; Rishikesh Singh; Sachchidanand Tripathi; Pramit Verma; Akhilesh Singh Raghubanshi
The interactive effects of light, nutrient availability and grass competition on seedlings of four tropical dry forest tree species, namely, Indian jujube (Ziziphus mauritiana), arjun (Terminalia arjuna), gum arabic (Acacia nilotica) and catechu (Acacia catechu), were evaluated in an experimental study at Banaras Hindu University, Varanasi, India. Full- and reduced- (20% of the full) sunlight, no-nutrient and nutrient supplementation, and presence of grass and no-grass conditions were taken in a split-plot design to observe the effects on the plant growth and leaf nutrient parameters. We observed a significant interaction between light and nutrient availability on total dry weight and relative growth rate for the tree seedlings of all the species. Seedling growth was lower in presence of grass under full sunlight condition with/without nutrient addition, and also under reduced sunlight condition with nutrient addition. However, leaf-N and -P concentration showed slight increase following nutrient addition across the species and light conditions. All the species responded positively to nutrient addition irrespective of light and grass conditions. Our study further indicates that nutrient addition under reduced light condition in tropical dry forests may be a possible strategy to ameliorate the negative impact of grasses on tree seedling growth. Overall, a better understanding of tree seedling establishment in the presence of grasses is of utmost importance for the development of management plans that may improve the diversity of tree species in tropical dry forests. © 2020 The Ecological Society of Japan
Effects of light availability on leaf attributes and seedling growth of four tree species in tropical dry forest
(Springer, 2020) Sachchidanand Tripathi; Rahul Bhadouria; Pratap Srivastava; Rajkumari S. Devi; Ravikant Chaturvedi; A.S. Raghubanshi
Background: In tropical dry forests, variation in understory light availability due to season and canopy tree density could be a governing factor in establishment and growth of tree seedlings. Species with varying life history traits are expected to respond differentially to such heterogeneity. We investigated the response of seedlings of four tree species in a tropical day forest in relation to spatiotemporal variability of light. We attempt to explore the role of leaf attributes in explaining intra- and inter-specific variations in relative growth rate. Four study sites, each with three contrasting canopy conditions, were selected along a soil moisture gradient. Seedlings of four tree species (viz., Acacia catechu, Bridelia retusa, Lagerstroemia parviflora, and Shorea robusta), varying in life history traits, were monitored for seasonal variations in growth traits across canopy condition and sites for 2 years. Results: We observed a larger variation in leaf attributes for pioneer species. A. catechu showed highest mean values for leaf dry matter content, leaf nitrogen concentration, leaf phosphorus concentration, net stomatal conductance, net photosynthetic rate, and relative growth rate in high light conditions. S. robusta and B. retusa demonstrated highest mean values for all the leaf attributes (except leaf dry matter content) in low light conditions. However, intermediate values for leaf attributes were observed in L. parviflora which preferred moderate light conditions. Conclusions: Seasonal variations in light availability at the forest floor appear to play an important role in the establishment and growth of tree seedlings in seasonal dry forests. Leaf attributes can be used to explain intra- and inter-specific variation in response to light availability. Leaf attributes in combinations can be used to predict relative growth rate of tree species in tropical dry environment, which apart from soil moisture is also determined by light availability due to seasonal changes and canopy tree density. © 2020, The Author(s).
Engineered Nanoparticles in Smart Agricultural Revolution: An Enticing Domain to Move Carefully
(Springer Nature, 2021) Pratap Srivastava; Rishikesh Singh; Rahul Bhadouria; Dan Bahadur Pal; Pardeep Singh; Sachchidanand Tripathi
Nanotechnology may potentially benefit our agro-ecosystems in multiple ways, primarily via reduction in agricultural inputs without yield penalty and enhanced absorption of nutrients by the plants. In this regard, nano-fertilizers (such as engineered metal oxide or carbon-based nano-materials, nano-coated fertilizers, and nano-sized nutrients), and nano-pesticides (inorganic nano-materials or nano-formulations of active ingredients), might bring targeted as well as controlled release of agrochemicals in order to tap the fullest biological efficacy in already stressed agro-ecosystems, without over-dosages and leach-outs. Therefore, such nano-tools may multiply the agricultural yield, providing protection against various pests and diseases, without polluting our soil and water ecosystems at the same time. Though nanotechnology may provide potential solutions on such critical and persistent issues in agricultural management and activities; however, new environmental and human health hazards from their applications itself may pose unforeseen challenges to the humankind. For example, the biosafety, adversity, unknown fate, and acquired biological reactivity/toxicity of these nano-materials once dispersed in environment after application are still an unknown and threatening area, which needs to be investigated carefully and scientifically, before its open field use in our agro-ecosystems. Among other potential benefits, nano-tools may also be utilized for the rapid disease diagnostic in field crops and monitoring of the packaged food quality and contaminations. Similarly, the quality and health of soils and plants can be regularly monitored in real-time manner with the help of sensors based on highly sensitive nano-materials. However, a responsible regulatory consensus on nanotechnology application in agriculture needs to be developed, based upon profound scientific foundations. This chapter explores the area of nanotechnology in revolutionizing agriculture in a smart way via its known interactions with plants and soil microorganisms so far in the literature. © 2021, Springer Nature Switzerland AG.
Exploring soil responses to various organic amendments under dry tropical agroecosystems
(Elsevier, 2020) Rishikesh Singh; Pratap Srivastava; Pramit Verma; Pardeep Singh; Rahul Bhadouria; Vipin Kumar Singh; Hema Singh; A.S. Raghubanshi
External input-based intensive agriculture practices have resulted in increasing food supply at the cost of considerable deterioration in soil quality and health. In addition, the release of various greenhouse gas emissions has also increased in recent years. For restoring soil health and productivity, and climate change mitigation, various organic amendments have been recommended for application in the soil. Depending upon the climatic variability, the soil responds differently to different amendments. Tropical agroecosystems are one of the extensively cultivated areas, and therefore, several studies dealing with agroecosystem responses have been performed under the present climate change scenario. In this chapter, we have explored the responses of the soil ameliorated with various organic amendments such as organic manure/compost, microbial fertilizers, vermicompost and biochar; and the impact of various amendments on soil physicochemical and biological properties. Moreover, soil respiration and microbial biomass under soils receiving these amendments have also been explored as the key indicators of soil viability. Overall, the chapter would provide a thorough understanding of the soil responses under different organic amendments in the present climate change scenario. © 2020 Elsevier Ltd. All rights reserved.
Interactive effect of water and nutrient on survival and growth of tree seedlings of four dry tropical tree species under grass competition
(International Society for Tropical Ecology, 2017) Rahul Bhadouria; Rishikesh Singh; Pratap Srivastava; Sachchidanand Tripathi; A.S. Raghubanshi
The increasingly degrading dry tropical forests due to anthropogenic perturbations may further show significant species and individual loss under changing climate condition. It is attributed to the later effect on soil water and nutrient availability, which may variably change the competitive ability, and thus survival of tree species seedlings. Currently, determining the response of tree species seedlings to environmental changes in dry tropical ecosystem is a key challenge. Therefore, understanding of factors, which govern the seedling characteristics, are necessary for maintenance and regeneration of these forests. Here, we aim to examine that how nutrient, water and grass interactively affect the tree seedling survival and growth of four dry tropical species viz., Ziziphus mauritiana and Terminalia arjuna (non-leguminous), and Acacia nilotica and Acacia catechu (leguminous). These four species were subjected to eight different combinations of treatments based on water availability, nutrient supplementation and grass competition. Their responses in terms of survival and growth parameters (i.e. height, circumference, aboveground dry weight, number of leaves, leaf area and relative growth rate) were recorded in each combination. It was observed that water and nutrient interactively affected the seedling growth significantly. Under all treatment combinations, leguminous species exhibited higher survival than non-leguminous species, however, a reverse trend was observed for seedlings growth parameters. Presence of grass had significant negative effect on seedling growth in all treatment combinations; however non-leguminous species showed more pronounced effect than leguminous species. We observed a considerable variation in the seedlings growth response of different tree species to the variation in growth conditions in dry tropical environment. The study provides a mechanistic insight about the change in forest community structure with the environmental changes, which would help in devising some management strategies to conserve and restore the dry tropical forest. © International Society for Tropical Ecology.
Metal-oxidizing microbes and potential application in bioremediation
(Elsevier, 2020) Vipin Kumar Singh; Anand Kumar Chaudhari; Kin Israel R. Notarte; Ajay Kumar; Rishikesh Singh; Rahul Bhadouria
Rapid development of different metal-based industries and mining activities producing huge amount of metal-laden wastes has considerably deteriorated the quality of water and soil around the globe. The application of metal-based fertilizers has further aggravated the environmental contamination multifolds. Most of the metals released into water and soil ultimately find their ways into different plants and animals causing hazardous effects. The variety of microbes dwelling in metal-contaminated water and soil has evolved different oxidative mechanisms to escape the toxicity of metals. Some of the metal-oxidizing microbes derive energy during oxidation and produce metal oxides possessing the characteristic potential to adsorb toxic metal ions. The microbes can oxidize different metals such as iron, manganese, arsenic, and antimony present in their vicinity by cellular biochemical processes and thus offer an environment-friendly option for bioremediation of metal-contaminated water and soil. Very often, the oxidized forms of metals produced by microorganisms are more efficient adsorbent as compared to chemically synthesized metal oxides. Such metal-oxidizing microorganisms developed on filter could be employed for treatment of variety of metal-laden water and wastewater. The present chapter has tried to deal with different metal-oxidizing microbes and their possibility in bioremediation. © 2021 Elsevier Inc.
Mycoremediation of agrochemicals
(Elsevier, 2020) Rahul Bhadouria; Somenath Das; Ajay Kumar; Rishikesh Singh; Vipin Kumar Singh
Extensive application of herbicides, pesticides, weedicides along with nitrogen- and phosphate-based fertilizers has deteriorated the physicochemical and biological attributes of agricultural ecosystem, in addition to the resistance emergence in insect pests. Currently, many of the employed agrochemicals are of persistent nature and pose serious hazards to human and environment due to their biomagnifying nature at different trophic levels. The technological advances for the management of agrochemical contaminated soil system may involve different physical and chemical treatment methods. These methods are very much expensive, nonecofriendly, and may sometime lead to generation of even very toxic compounds of more persistent nature than pollutants intended for treatment. Contrary to this, bioremediation based on fungi may offer an easy, sustainable, and ecofriendly technology for restoration of contaminated soil system. In the present chapter, we have tried to discuss different anthropogenically introduced contaminants into soil, their impacts on natural soil characteristics, effect on native microbial community, beneficial soil annelids, arthropods, as well as different fungal genera involved in degradation, strategies based on fungal metabolism for degradation of different chemical contaminants, and limitations associated with application of fungi in agroecosystem to make the soil free from hazardous agrochemicals. © 2020 Elsevier Ltd. All rights reserved.
Nanocatalyst types and their potential impacts in agroecosystems: An overview
(Elsevier, 2019) Rahul Bhadouria; Disha Mishra; Vipin Kumar Singh; Pardeep Singh; Pratap Srivastava; Sachchidanand Tripathi; Rishikesh Singh
Agricultural intensification by the increased inputs of agrochemicals has resulted in several negative environmental consequences. Currently the precise use of agrochemicals is being recommended to improve crop yield and environmental health. Application of various precision agricultural practices is being promoted to attain the agricultural sustainability. Nanotechnology as a modern tool has been considered as a potential tool for the precise application of agrochemicals and efficient utilization by the crop plants in the agroecosystems. In this context, the application of spent nanocatalysts in the agroecosystems has been increased considerably for the management of these spent catalysts. Numbers of studies have shown significant impact of spent nanocatalysts on plant germination and growth behaviors. In this chapter a brief insight has been given on the development and application of novel nanomaterials (NMs) in agriculture and environment along with their fate and behavior. Further, recent developments in plant science regarding nanobiotechnology that focuses on agricultural practices, plant growth, and yield are also emphasized. Moreover an effort has been made to collate the studies dealing with the utilization of spent nanocatalysts and nanomaterials used in various value-added products in the agricultural systems. © 2020 Elsevier Inc. All rights reserved.
Nanofiltration technology for removal of pathogens present in drinking water
(Elsevier, 2020) Rishikesh Singh; Rahul Bhadouria; Pardeep Singh; Ajay Kumar; Shilpi Pandey; Vipin Kumar Singh
Water is one of the most important natural resources supporting the diverse array of life present on earth. Rapid diminution of fresh potable water reserves, contamination of existing ones, and generation of large amount of wastewater due to anthropogenic activities have compelled the scientists to develop methods to treat the contaminated water. Across the globe, millions of people are inaccessible to fresh drinking water. Multiple health issues are linked with the purification of drinking water supplied through different ways including bottled water, tap water, and borewells. The drinking water is most often contaminated with pathogenic microbes including bacteria, viruses, and protozoa beyond the recommended limits causing serious human health hazards. The pathogenic microbes commonly detected in water supplies include those related to dysentery, typhoid fever, vomiting, and cholera. Therefore, removal of human pathogens from drinking water is essential for health security. Numbers of physical and chemical techniques have been developed to make available the pathogen free drinking water. Techniques employing membranes for trapping hazardous biological contaminant are currently gaining momentum worldwide. This chapter deals with the sources of pathogens in drinking water, important waterborne diseases, and different aspects of nanofiltration techniques over other commercially used methods for removal of pathogens. © 2020 Elsevier Ltd. All rights reserved.
Organic amendment impact on SOC dynamics in dry tropics: A possible role of relative availability of inorganic-N pools
(Elsevier B.V., 2016) Pratap Srivastava; Rishikesh Singh; Rahul Bhadouria; Sachchidanand Tripathi; Pardeep Singh; Hema Singh; Akhilesh Singh Raghubanshi
Organic amendment in agro-ecosystems positively affects the soil organic C (SOC) dynamics, both alone and in combination with mineral fertilizers. Therefore, it is being widely advocated in recent times for the restoration of SOC. Limited understanding exists on how these agro-management practices affect SOC dynamics in the dry tropical agro-ecosystems. We, therefore, aim to investigate the impact of sole organic and combined (organic + inorganic) amendment on SOC dynamics, taking the precursor native forest as a reference. SOC, soil CO2 efflux, soil physico-chemical, microbial and aggregate characteristics were observed in these systems. Our results demonstrate that organic and combined amended systems behaved distinctly as compared to reference system. However, combined amended system was found more C protective as compared to organic amended system. Further, combined amended system showed higher SOC, soil bulk density, NH4+-N, NH4+-N to NO3−-N ratio, microbial biomass C/N ratio (MBC/MBN), β-glucosidase activity, mineral fractions, and aggregate-associated total C as compared to organic system. However, soil CO2 efflux, pH, moisture content, NO3−-N, MBC, MBN, percent labile C in meso- and micro-aggregate, and labile C stock in micro-aggregate showed an opposite trend. Soil moisture and macro aggregate water stability were found important drivers of SOC dynamics in dry tropical ecosystems. SOC dynamics across the studied agroecosystems was found associated with the shift in MBC, MBC/MBN and β-glucosidase activity. The consequent shift in the relative availability of soil inorganic-N pools (i.e. soil NH4+-N to NO3−-N ratio) was identified crucial in this regard. Its relationship with soil microbial biomass, in addition to bulk density, aggregate size distribution and labile C concentration and stock in meso- and micro-aggregates depicts its possible importance in SOC dynamics. Results suggest that higher soil NH4+-N to NO3−-N ratio in combined amended system may be responsible for its relatively higher C protective nature. It might be attributed to its relationship with labile C in meso- and micro-aggregate fractions; however, micro-aggregate appears to be relatively more important in this regard. © 2016 Elsevier B.V.
Perspectives in desulfurization of coal using microbes
(Elsevier, 2020) Vipin Kumar Singh; Rishikesh Singh; Ajay Kumar; Rahul Bhadouria; Kin Israel Notarte
Coal is one of the most commonly utilized fossil fuel for energy production across the globe leading to higher amount of emission of sulfur dioxide (SO2) in the atmosphere. Combustion of coal containing higher contents of sulfur is a major factor responsible for acid rain and associated environmental degradation. The currently used physicochemical approaches for removal of sulfur from coal are expensive, toxic in nature, and inappropriate for different types of coal. The application of microbial resources for removal of sulfur from coal is an ecofriendly technique and could be successfully employed at industrial scale after laboratory scale process optimization. The process of sulfur removal by microbes is carried out by enzymes and is considerably influenced by different factors, including pH, temperature, nutrient composition, shaking or standing condition, coal types, and most importantly type of microorganisms used. Different bacteria and fungi isolated from coal contaminated site as well as noncontaminated site exhibiting sulfur removal potential can be used as next generation tool for the development of clean coal technology. Furthermore, through the application of modern genetic manipulation techniques, enhanced expression of genes responsible for desulfurization can be performed in order to accelerate the process of sulfur removal from coal. The present chapter is prepared with an aim to discuss the diverse microbial population participating in desulfurization, their efficiency, mechanism of sulfur elimination, role of important environmental factors along with possible applications, and challenges in industrial scale sulfur removal. © 2021 Elsevier Inc.
Phytoremediation of organic pollutants: Current status and future directions
(Elsevier, 2019) Sachchidanand Tripathi; Vipin Kumar Singh; Pratap Srivastava; Rishikesh Singh; Rajkumari Sanayaima Devi; Arun Kumar; Rahul Bhadouria
Phytoremediation is the technology based on plants for extraction, sequestration, and/or degradation of environmental contaminants. The process of phytoremediation is a green and nondestructive suitable alternative to widely practiced physicochemical approaches. Plant-based contaminant removal could be directly inside the plant or outside the plant body (explanta). The process of phytoremediation involves different biochemical and physiological mechanisms facilitated by absorption, accumulation, sequestration, transport, and degradation. Furthermore, plants are equipped with the property of metabolizing hazardous organic contaminants into nontoxic or comparatively less toxic forms. Numbers of organic contaminants including polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and halogenated hydrocarbons have been targeted for effective remediation by utilization of diverse plant groups. Currently, many experimental investigations have been conducted to develop genetically modified plants and endophytic bacterial strains harboring genes of interest displaying efficient contaminant degradation ability. Although the phytoremediation strategy for cleaning the organic contaminant seems promising with reference to the process cost, assessment, maintenance of soil biological activity, and carbon capture efficiency, the field-scale application has limited success because of changing environmental conditions, slow growth rate, and adaptability under given natural environment. Some of the limitations associated with phytoremediation could be managed through genetic engineering approaches; however, regulatory issues regarding their release under field conditions and very low public acceptance make the process unsuccessful at field scale. Essentially, extensive laboratory investigations are still needed to deploy the phytoremediation strategies for effective contaminant removal. The successful utilization of recombinant DNA technology together with the existing information on plant physiology, rhizosphere microbiology, and root exudates chemistry could be instrumental in gaining deep insights into the process of environmental contaminant removal. © 2020 Elsevier Inc. All rights reserved.
Preface
(Springer Nature, 2021) Pardeep Singh; Rishikesh Singh; Pramit Verma; Rahul Bhadouria; Ajay Kumar; Mahima Kaushik
[No abstract available]
Relative availability of inorganic N-pools shifts under land use change: An unexplored variable in soil carbon dynamics
(Elsevier B.V., 2016) Pratap Srivastava; Praveen Kumar Singh; Rishikesh Singh; Rahul Bhadouria; Dharmendra Kumar Singh; Shivam Singh; Talat Afreen; Sacchidanand Tripathi; Pardeep Singh; Hema Singh; Akhilesh Singh Raghubanshi
Land use change (LUC) may detrimentally affect the soil organic carbon (SOC) within different soil fractions; directly supplemented by significant contribution to soil CO2 efflux (SCE). To understand the governing mechanism, experimental data were collected for SOC and SCE along with soil physico-chemical, microbial and aggregate characteristics across adjacent secondary forest (SF)-grassland (GL)-cropland (CL) sequence in dry tropical ecosystems. A significant change in SOC and SCE was observed from SF to GL and CL systems, respectively; though moderately from GL to CL system. Respective decrease in SOC (31 and 42%); soil ammonium-N to nitrate-N ratio (ANR; 96 and 86%), microbial biomass C (MBC; 30 and 50%), nitrogen (MBN; 6 and 33%) and MBC/MBN ratio (25 and 24%); whereas increase in SCE (43 and 57%) and soil nitrate-N availability (340 and 592%) was observed from SF to GL and CL systems. Moreover, aggregate physical distribution shifted toward smaller size fractions; whereas aggregate-associated total C and KMnO4-labile-C concentration and carbon management index (CMI) across aggregate-size fractions decreased linearly with the land use sequence. SOC was majorly governed by macro-aggregate water stability (WASmacro) and MBC; whereas SCE by CMI of macro-aggregate (CMImacro) fraction. Furthermore, the ANR showed positive correlation with microbial (i.e. MBC and MBC/MBN ratio) and macro-aggregate physical (i.e. WASmacro) and chemical stability (i.e. CMImacro). It indicates that a shift in the microbial community with the land use may affect the relative availability of inorganic N pools and associated aggregate characteristics. Thus, our results indicate that a shift in ANR with LUC may be an unexplored and crucial indicator of soil C dynamics mediating quantitative and qualitative changes in microbial and aggregate characteristics in dry tropical ecosystems. Further, a critical emphasis is needed on the relationship of SOC dynamics with ANR for future studies at various spatiotemporal scales worldwide to recognize its potential role as ecological indicator of SOC dynamics. Also, its inclusion under climatic models may help to better predict the future climate. © 2016 Elsevier Ltd. All rights reserved.
Riparian land uses affect the dry season soil CO2 efflux under dry tropical ecosystems
(Elsevier B.V., 2017) Rishikesh Singh; Hema Singh; Shivam Singh; Talat Afreen; Shweta Upadhyay; Ashutosh Kumar Singh; Pratap Srivastava; Rahul Bhadouria; A.S. Raghubanshi
Riparian ecosystems are amongst the most vulnerable ecosystems of the world. The natural gradients and increasing human perturbations under these ecosystems can be explored for understanding the soil carbon (C) dynamics, especially soil carbon dioxide (CO2) efflux. However, studies on soil CO2 efflux and its governing variables under different land uses of dry tropical riparian ecosystems are limited. Therefore, the present study aimed (1) to assess the impact of riparian land use on soil CO2 efflux, and (2) to identify the key drivers of soil CO2 efflux along the river Ganga, Varanasi, India. The riparian land uses taken in this study were moist sandy flat (MSF), uncultivated sandy land (USL) and cultivated sandy land (CSL) depending upon their slope and distance from river body to upland, respectively. Soil CO2 efflux and other soil biophysical properties were measured at 54 locations distributed in six sites having these land uses, in dry season of 2014–15. Soil biophysical properties considered in this study were soil organic C, soil moisture, bulk density, porosity, fine particles, microbial biomass C and soil pH. Riparian land uses were found to have significant impact over soil CO2 efflux with a respective increase of 222, 424 and 63%, for MSF to USL, MSF to CSL, and USL to CSL land use transitions (P < 0.01), respectively. Similarly, the regulators of soil CO2 efflux varied with the land uses. It showed strong positive correlation with soil organic C (r = 0.81), fine particles (r = 0.64) and porosity (r = 0.61), whereas negative correlation with soil moisture (r = 0.61) and bulk density (r = 0.62) for overall dataset. However, soil organic C, fine particles, microbial biomass C and soil pH at MSF; soil organic C and microbial biomass C at USL; and soil moisture, porosity and microbial biomass C at CSL land uses were observed to regulate soil CO2 efflux. The findings revealed that riparian land uses have significant control over soil CO2 efflux and its biophysical regulators which have relative control over it. Soil organic C, soil moisture, fine particles, porosity and microbial biomass C were identified as prevalent regulators of soil CO2 efflux under dry seasons. Overall, the results indicate that the biophysical variables in addition to human interferences (CSL land use) have pronounced regulation over soil CO2 efflux in dry tropical riparian ecosystems. © 2017 Elsevier B.V.
Seed priming: state of the art and new perspectives in the era of climate change
(Elsevier, 2020) Vipin Kumar Singh; Rishikesh Singh; Sachchidanand Tripathi; Rajkumari Sanayaima Devi; Pratap Srivastava; Pardeep Singh; Arun Kumar; Rahul Bhadouria
The changing climatic and weather conditions have affected the global food supply, especially cereal crops. Worldwide agricultural production is considerably affected by climate change and pressure induced by the ever-increasing human population and their food demand. The production in agriculture is also affected by the insufficient availability of quality seeds and affordable cost for farmers. Interestingly, genetically engineered stress-tolerant genotypes could play an important role in improving ever-increasing food demand under changing climatic conditions. Generally, plant genetic resources are used for the development of genetically engineered stress-tolerant diverse varieties. New and improved varieties of crops with a wider range of adaptation under changing climatic conditions may be a good move toward combating food scarcity for the increasing population and climate change. Seed industry and seed priming (treatment) have played a vital role in increasing agricultural productivity. The adverse effects of climate change on seed productivity and agriculture industry can be minimized by improved genotype, breeding, genetic diversity, seed priming (treatment), seed certification, seed marketing, etc. There is an urgent need to enhance seed productivity and search for suitable geographic regions for enhancing quality seed production. For the certification of seed, international procedures must be adopted for all the geographical areas of the world. This will also help in ease in the availability of quality seeds to farmers and public participation in plant breeding for the seed industry. Seed biopriming is one of the vital technologies in the management of biotic as well as abiotic stresses and guarantees uniform stand establishment under a stressed environment. Therefore research programs encompassing the identification of quality plant genetic resources, genetic manipulations of novel biocontrol agents (fungal and bacterial strains), and other beneficial applications need to be devised. © 2020 Elsevier Ltd. All rights reserved.