Browsing by Author "Pratap Srivastava"

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A new insight into the warming potential of organically amended agro-ecosystems
(Springer Netherlands, 2018) Pratap Srivastava; Rishikesh Singh; Sachchidanand Tripathi; Hema Singh; Akhilesh Singh Raghubanshi; Pradeep Kumar Mishra
Organic fertilization enhances the global warming potential of the soil, which is primarily attributed to higher CO2 emission from the soil. However, long-term studies under organic fertilization to observe its impact on soil’s warming potential with respect to CO2 efflux are limited in the dry tropical ecosystem. Therefore, we observed the changes in soil organic matter (C, N), soil CO2 efflux (SCE), soil moisture, microbial biomass C, and dehydrogenase activity in the plots under 1, 3, 5, and 10 years of organic fertilization, designated as OM1, OM3, OM5, and OM10, respectively. Also, a nearby native forest was taken as a standard reference system (NF) in the present study for comparative purpose. We observed that organic fertilization significantly (P ≤ 0.05) increased soil organic carbon (SOC), soil organic nitrogen (SON), SCE, moisture, microbial biomass C, and dehydrogenase activity, whereas decreased the SOC/SON ratio after 10 years, which also approached closer to NF. However, only the plots under 10 years of organic fertilization showed SCE significantly (P ≤ 0.05) similar to NF. It indicates that long-term organic fertilization is required for the improvement in soil properties. SCE showed a significantly (P ≤ 0.05) higher value (on average, by 61%) in OM10 site as compared to OM1. However, SCE on unit C basis (SCER) showed no change (P > 0.05). This increase in SCE after 10 years of organic fertilization might be attributed to the significant (P ≤ 0.05) increase in SOC, soil moisture, microbial biomass C, and dehydrogenase activity. However, no change in SCER after 10 years shows that organic fertilization has possibly been misinterpreted with respect to their impact on soil’s global warming potential. It might be attributed to the C protective nature of the organic fertilization. Overall, our results contradict with the often publicized higher warming potential of the organically amended systems. This indicates that organic fertilization does not increase the soil’s global warming potential, which is often misrepresented because SCE is not observed with respect to the existing SOC content. © 2017, Springer Science+Business Media B.V.
An urgent need for sustainable thinking in agriculture - An Indian scenario
(Elsevier B.V., 2016) Pratap Srivastava; Rishikesh Singh; Sachchidanand Tripathi; Akhilesh Singh Raghubanshi
This article emphasizes on the present urgent need to think in "Holistic Dimensions" to achieve a sustainable agro-ecosystem. In this respect, the complex network of dynamic interactions in the agro-ecosystem soil at spatiotemporal dimensions holds crucial importance. It reflects the inherent tendency of dynamic ecosystems to achieve a more efficient state successively through improved interactions. The short-sighted and inefficient agro-management during Green Revolution decades has been detrimental to these interactions in agricultural soils, which is widely evident by its boomerang effects (i.e. declining efficiency, productivity and multi-functionality). It jeopardized the internal regulation in our agro-ecosystem's functioning by erosion of efficiency building interactions among biotic and abiotic components. Therefore, a bottom-up as well as top-down approach in the soil management is required to restore and sustain the unaccounted but indispensible ecological subsidies for sustainable agriculture and development, globally. We propose a "commercial ecological agriculture" which should be an amalgamation of sustainable agricultural practices and supported by a progressive co-ordination among all the stakeholders via participatory learning and adaptation with time. It should be least-disturbing, resilience-building, resource (i.e. energy and nutrient) use efficient, site-specific, labor and skill-intensive, low-input, diversified and integrated, and intimately harmonized with nature. It may potentially provide us agricultural sustainability with time in real sense. It would be primarily based on management of interactions indirectly through identification of integrative variables as surrogate, which may help to achieve internal regulation or self-reliance in agroecosystems. Further, it would be helpful to eliminate the widening socio-economic divide and in mitigation of global change in environment (i.e. air, water and soil) and climate. Additionally, it would improve and restore the multifaceted potential of soil, thus quality and productivity, through improved internal regulation on resource-use efficiency. © 2016 Elsevier Ltd. 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.
Current and emerging trends in bioremediation of petrochemical waste: A review
(Taylor and Francis Inc., 2017) Pardeep Singh; Rajat Jain; Neha Srivastava; Anwesha Borthakur; D.B. Pal; Rishikesh Singh; Sughosh Madhav; Pratap Srivastava; Dhanesh Tiwary; Pradeep Kumar Mishra
Various industries release harmful petrochemical contaminants into the environment. To treat these petrochemical contaminants at source, different physical, chemical, and biological methods have been proposed and applied worldwide. However, physical and chemical methods have their own advantages and limitations; in this review, we majorly focused on the biodegradation of petrochemical wastes. First, a background study on the literature available in this field is presented. Second is a review of the toxic effects of petrochemical waste and various physical and chemical processes, followed by elaborate biological processes available for petrochemical waste degradation. Further, different aspects of bioremediation, such as modes, factors, limitations, and future perspectives are critically reviewed and presented. It was found that most of the studies performed on bioremediation of petrochemical waste employed bacteria for the degradation purpose. Some studies also made use of algae, fungi, yeast, genetically modified organisms, biosurfactants, or a consortium of these microbes. Moreover, use of bioremediation is still limited at field scale due to certain limitations, which have been elaborated in this article. Overall, we strongly believe that with bioremediation capturing the attention of environmentalists worldwide, there is still a prevailing need to scale up from lab to land level applications and adaptations. © 2017 Taylor & Francis Group, LLC.
Effect of nanoscale TiO 2 -activated carbon composite on Solanum lycopersicum (L.) and Vigna radiata (L.) seeds germination
(Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University, 2016) Pardeep Singh; Rishikesh Singh; Anwesha Borthakur; Pratap Srivastava; Neha Srivastava; Dhanesh Tiwary; Pradeep Kumar Mishra
The extensive use of nanoparticles under different industrial processes and their release into the environment are of major concerns in the present global scenario. In the present study, the effects of activated carbon-based TiO 2 (AC-TiO 2 ) nano-composite on the seed germination of Solanum lycopersicum (tomato) and Vigna radiata (mungbean) were investigated. The size of nanoparticles used in the study ranged from 30 to 50 nm, and their concentrations were from 0 to 500 mg L −1 . The composites were synthesized by sol–gel method and further characterized by scanning electron microscopy, Energy-dispersive X-rays spectroscopy (EDX), Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction to investigate all the surface structural and chemical properties of AC-TiO 2 nano-composite. The results showed that increase in nano-composite concentration improves the germination rate and reduces germination time up to a certain concentration. Therefore, employing AC-TiO 2 nano-composites in suitable concentration may promote the seed germination and also reduce the germination time in Solanum lycopersicum and Vigna radiata. Further, it may help to understand the interface of TiO 2 nanoparticles with the environment and agriculture before its application to the field. © 2016, Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University and Springer-Verlag Berlin Heidelberg.
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.
Geomorphologic heterogeneity influences dry-season soil CO2 efflux by mediating soil biophysical variables in a tropical river valley
(Birkhauser Verlag AG, 2019) Rishikesh Singh; Ashutosh Kumar Singh; Shivam Singh; Pratap Srivastava; Hema Singh; Akhilesh Singh Raghubanshi
Riparian landscapes are characterized by heterogeneous geomorphological structures such as erosive and depositional habitats, and therefore, may have variable soil biophysical properties. The heterogeneity in geomorphological structures and related biophysical properties would exert spatial variations in the soil CO2 efflux (SCE). However, studies assessing the relative control of biophysical variables on the SCE under such complex landscapes of dry tropical ecosystems are limited. Therefore, we assessed the effect of heterogeneity in geomorphological structures on SCE, and identified the key biophysical variables governing SCE along the riparian landscapes. The SCE, soil organic C (SOC), microbial biomass C (MBC) and pH were found to vary significantly (P < 0.05) along riparian habitats, and SCE was found 73% higher at erosive than depositional habitats. SOC was found as a prominent regulator of SCE which alone explained about 80% of the variability in SCE. Moreover, soil moisture, fine particles, pH and MBC also showed strong control on SCE along riparian landscapes. Stepwise regression analysis revealed that after excluding SOC as a main variable, soil moisture explained 32% of the variability in SCE at overall landscape level whereas fine particles and MBC explained 78% and 23% of the variability in SCE at erosive and depositional habitats, respectively. Overall, results indicate that erosive habitats are the major source of SCE, and variation in biophysical variables is greatly affecting the SCE at these habitats. Therefore, further assessment of interactions of SCE, soil biophysical parameters and their regulatory components such as hydrology, vegetation and anthropogenic activities at micro—(site and land-use) as well as macro—(landscape) scales would help to understand the soil C dynamics along the heterogeneous riparian landscapes under climate change scenarios. © 2019, Springer Nature Switzerland AG.
Herbaceous species diversity and soil attributes along a forest-savanna-grassland continuum in a dry tropical region
(Elsevier B.V., 2017) Rishikesh Singh; R. Sagar; Pratap Srivastava; Pardeep Singh; J.S. Singh
Dry tropical vegetation is under major pressure of degradation due to various anthropogenic interferences and is characterized by the patches of forest, savanna and grassland systems. These adjacent systems may represent a gradient of various ecological attributes which can be better understood by studying these in a continuum approach to recognise changes at grassroots level. The herbaceous vegetation, a dynamic layer of an ecosystem, acts as an indicator of the environmental changes. The present study is designed to assess the herbaceous plant diversity and soil attributes along the dry deciduous forest-savanna-grassland continuum. A total of nine sites equally distributed in forest, savanna and grassland systems of Vindhyan region were selected. Soil moisture, water holding capacity, carbon, nitrogen, phosphorus and species richness, evenness, diversity and plant biomass were measured at each site. The results showed significant changes in soil attributes and herbaceous species composition, diversity and biomass along the continuum. Forest exhibited higher soil moisture, carbon and nitrogen contents than the savanna and grassland, while the herbaceous species diversity and biomass were higher in grassland vegetation. Savanna revealed intermediate levels of soil water availability, soil nutrients, community composition and species diversity of the herbs. The results showed that the herbaceous diversity was maximum in the grassland followed by savanna and forest. Moreover, a change in community composition and plant functional attributes was also observed. Evolvulus nummularius-Justicia simplex, Justicia simplex-Evolvulus nummularius and Cynodon dactylon-Cyperus compressus communities characterised the forest, savanna and grassland vegetation, respectively. Fabaceae was the most dominant family having the highest number of species in grassland followed by savanna and forest vegetation. Correlation analysis revealed a significant interaction between soil water and nutrient availability with vegetation parameters. Overall, heterogeneity of soil attributes maintaining the community structure and species diversity are essential components for understanding the ecology of herbaceous vegetation in dry tropical ecosystems. The findings of this study may contribute to the holistic understanding and development of ecological management tools for such a continuum. © 2017 Elsevier B.V.
Human overpopulation and food security: Challenges for the agriculture sustainability
(IGI Global, 2019) Rishikesh Singh; Pratap Srivastava; Pardeep Singh; Shweta Upadhyay; Akhilesh Singh Raghubanshi
World population is rapidly growing and expected to reach in between 8.5 to 12 billion by 2100. More than 75% of the population is expected to inhabit in the African and Asian countries having most of the developing nations. The overpopulation leads to a state of food insecurity that induced the evolution of resource-exhaustive agriculture causing irreparable environmental damages. Now the challenge is to feed more with less environmental damages. Adoption of technologically-sound, traditional knowledge inclusive, socio-economically sensible recommended agricultural practices can be the basis for achieving future dietary demands. However, before wider recommendation, their environmental impact assessment at various sustainability issues is necessitated for a holistic understanding of the future agriculture. The challenges of overpopulation and food security can only be managed by identifying the core areas of research and development under different agricultural sectors. The present chapter will provide a brief dimension on some of these key issues. © 2019, IGI Global.
Human overpopulation and food security: Challenges for the agriculture sustainability
(IGI Global, 2016) Rishikesh Singh; Pardeep Singh; Pratap Srivastava; Shweta Upadhyay; Akhilesh Singh Raghubanshi
World population is rapidly growing and expected to reach in between 8.5 to 12 billion by 2100. More than 75% of the population is expected to inhabit in the African and Asian countries having most of the developing nations. The overpopulation leads to a state of food insecurity that induced the evolution of resource-exhaustive agriculture causing irreparable environmental damages. Now the challenge is to feed more with less environmental damages. Adoption of technologically-sound, traditional knowledge inclusive, socio-economically sensible recommended agricultural practices can be the basis for achieving future dietary demands. However, before wider recommendation, their environmental impact assessment at various sustainability issues is necessitated for a holistic understanding of the future agriculture. The challenges of overpopulation and food security can only be managed by identifying the core areas of research and development under different agricultural sectors. The present chapter will provide a brief dimension on some of these key issues.
Impact of rice-husk ash on the soil biophysical and agronomic parameters of wheat crop under a dry tropical ecosystem
(Elsevier B.V., 2019) Rishikesh Singh; Pratap Srivastava; Pardeep Singh; Archana Kumari Sharma; Hema Singh; Akhilesh Singh Raghubanshi
Several alternative amendments like organic manure and biochar have been proposed for revitalizing the degrading soil viability and fertility for sustainable agriculture, globally. However, detailed field-scale studies focussing on the soil and agronomic parameters of crops under these amendments are limited in dry tropical ecosystems. Therefore, we studied the impact of various soil amendments viz., rice-husk ash (RHA) and farm-yard manure (FYM) along with mineral fertilizer on soil biophysical and agronomic parameters of wheat crop. We specifically explored the impact of the amendments on soil CO2 efflux (SCE, under different growth stages) and the harvest index of wheat crop, which are considered as the key indicators of soil viability and agronomic efficiency, respectively. SCE, soil moisture, soil temperature, soil N, microbial biomass and soil pH were found significantly varying under different treatments (P < 0.05). SCE was found maximum under sole FYM applied and minimum under mineral fertilizer applied treatments, whereas RHA application lowered the SCE as compared to sole FYM application. Moreover, SCE showed variation with plant growth stages, and found maximum during stem elongation followed by heading stage whereas minimum during ripening stage. Soil moisture was found to have considerable regulation for the overall variation in SCE (r2 = 0.17; P = 0.04). In contrast to the soil properties, agronomic parameters (except harvest index) were found higher under mineral fertilizer applied treatments followed by sole FYM and combined FYM + RHA treatments, whereas sole RHA applied treatment showed minimum values. However, significant variations were observed only for harvest index, aboveground dry matter, grain and straw yields (P < 0.05). Further, harvest index was found highest under sole and combined FYM and RHA applied treatments whereas lowest in mineral fertilizer applied treatments. Soil C/N ratio (r2 = 0.16; P = 0.04) and panicle length (r2 = 0.18; P = 0.03), respectively as soil and agronomic parameters, have been found to have considerable control over harvest index. The findings revealed that soil viability is higher under sole FYM and combined FYM + RHA treatments whereas mineral fertilization enhances agronomic performance. Based on the studied two indicators, we conclude that both soil and agronomic sustainability can be maintained by using a combination of organic (FYM and RHA) fertilization with reduced inputs from mineral fertilizers. However, it further needs exploration for various soil and plant eco-physiological parameters of different crops at field level for wider adaptation in the dry tropical region. © 2018 Elsevier Ltd
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.
Multifaceted application of crop residue biochar as a tool for sustainable agriculture: An ecological perspective
(Elsevier B.V., 2015) Rishikesh Singh; J. Nagendra Babu; Rabindra Kumar; Pratap Srivastava; Pardeep Singh; Akhilesh Singh Raghubanshi
Lignocellulosic crop residue biomass, in surplus, is of vital importance due to its multifaceted utilization potential on- and off-site to agricultural systems; therefore, its management is essential for sustainable agriculture. The malpractice of open crop residue burning leading to the brown cloud phenomenon and contributing significantly to atmospheric heterogeneity through enhanced gaseous and particulate emissions is of greater off-late concern. Available traditional crop residue management (CRM) technologies have not achieved wider adaptation; therefore, recently thermochemical conversion has been foreseen as an interesting tool for potential CRM under changing climate scenario. Biochar, a by-product of thermochemical processes, has been evaluated as a potential soil ameliorant and C sequestration agent. As soil ameliorant, it improves soil basic properties directly along with subdued release of greenhouse gases from agroecosystems, provides adsorption surface to agrochemicals and improves essential nutrient dynamics. Since the potential benefits of biochar in soil are governed by initial pyrolysis conditions and soil types; therefore, its wider utilization potential as suitable tool in sustainable agriculture and climate change mitigation needs to be critically analyzed before its specific recommendation to an agroecosystem. The present review provides a critical insight on current research on various aspects, particularly ecological, of crop residue biochar starting from the feedstock sources, pyrolysis conditions and changes after application. Additionally, a brief account is given on the agronomic relevance and major constraints of biochar amendment as an ecological engineering tool for sustainable agriculture. After reviewing various aspects of crop residue as feedstock, we recommend its use as a blend, rather than sole use, along with several other lignocellulosic materials under pyrolysis process as well as ameliorating agent. © 2015 Elsevier B.V.
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.
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.
Photocatalytic degradation of Acid Red dye stuff in the presence of activated carbon-TiO2 composite and its kinetic enumeration
(Elsevier Ltd, 2016) Pardeep Singh; M.C. Vishnu; Karan Kumar Sharma; Anwesha Borthakur; Pratap Srivastava; D.B. Pal; Dhanesh Tiwary; Pradeep Kumar Mishra
The present paper deals with photocatalytic degradation of effluents from dye industries which have known toxic impacts on flora and fauna. Nano composite of titanium dioxide having activated carbon (TiO2/AC) base was synthesized using sol-gel method. The synthesized catalyst was then characterized by Fourier Transform-Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), X-ray Diffractometry (XRD) and Brunauer Emmet Teller (BET) surface area analyzer. A synthetic solution of AR-131 dye was subjected to photocatalytic degradation using TiO2/AC nano composite as catalyst. The degradation mechanisms of dye (AR-131) via photo-catalysis were found to follow a first order kinetics mechanism (vis. Langmuir- Hinshelwood Model). Toxicity of spent catalysts was further investigated in seed germination of Vigna radiata. Enhanced seed germination along with elongation of root and shoot was noticed up to the concentration of 500 ppm confirming its non toxicity. © 2016 Elsevier Ltd.
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.