Browsing by Author "Preeti Verma"

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Assessment of potential health risks due to heavy metals through vegetable consumption in a tropical area irrigated by treated wastewater
(Kluwer Academic Publishers, 2015) Preeti Verma; Madhoolika Agrawal; R. Sagar
Consumption of wastewater-irrigated vegetables is a common practice in developing countries including India. The wastewater irrigation gradually raises the contents of heavy metals in soils and vegetables. The consumption of heavy metal-rich vegetables may cause serious risk to the human health. Therefore, quantification of heavy metals in vegetables collected from wastewater-irrigated field is needed as proportion of farmers using wastewater for irrigation is increasing due to scarcity of water. The aim of the present study was to assess the heavy metal accumulation and the potential human health risks associated with consumption of contaminated vegetables irrigated with waste (WWT) and mixed wastewater (MWWT), grown in an agricultural area of Bhagwanpur, near Banaras Hindu University, Varanasi, India. Seven common vegetables growing at two differentially irrigated areas (WWT and MWWT) were considered for the study. At each site, three samples, each from water, soil and different vegetables, were taken. The samples after digestion were analysed for heavy metal contents using atomic absorption spectrophotometer. Heavy metal contents in soils, vegetables, transfer factor (TF) from soil to vegetables, metal pollution index (MPI) and their health risk in form of target hazard quotients (THQs) were calculated. Results showed significantly higher contents of heavy metals in water, soil and vegetable at WWT than MWWT. The TF value of Cd was notably greater in WWT compared to the MWWT. The values of THQ in children and adults were >1 for Pb and Cd in case of all vegetables at both WWT and MWWT. Among the vegetables, MPI was highest for B. vulgaris followed by B. botrytis, B. capitata, R. sativus, B. nigra, A. sativum and S. tuberosum. THQ for both categories were mostly higher for WWT compared at MWWT, suggesting a greater health risk to local residents from vegetable of the former than latter site. The present study suggests regular monitoring of water quality prior to discharge for irrigation uses and also points out to adopt better wastewater management strategies for proper utilization and disposal of wastewater. © 2015, Springer Science+Business Media New York.
Changes in species composition, diversity and biomass of herbaceous plant traits due to N amendment in a dry tropical environment of India
(Oxford University Press, 2014) Punita Verma; R. Sagar; Hariom Verma; Preeti Verma; Dharmendra K. Singh
Aim: European and North American studies have suggested that nitrogen (N) depositions reduce plant diversity and increase primary productivity due to changes in plant traits. To predict the vegetation response to future global change, experimental validations from other regions are widely needed. We assessed the effects of N treatment by urea fertilization on the diversity and biomass of the herbaceous plant traits (HPTs) in a dry tropical environment of India. Methods: Diversity and biomass of different HPTs were determined on the basis of data collected in year 2010, from 135, 1 m x 1 m plots distributed over 15 locations. The plots were treated with urea fertilizer in different doses (Control, 60kgNha-1 yr-1 and 120kg N ha-1yr-1) since 1st January 2007. The plots were ordinated and data were subjected to appropriate statistical analyses. Important Findings: Correspondence analysis (CA) suggested uniqueness of species composition due to N amendment. Species number and biomass of the trait categories varied due to N fertilization and traits. All studied trait categories (except N-fixers) yielded maximum mean species number at moderate level of N fertilization. Different levels of N fertilization exhibited different species diversity-primary productivity (D-P) relationships. Further, study showed reduction in plant diversity due to increase in biomass at high rates of N addition. Conclusions: Tall, erect, non N-fixers, annuals, grasses HPTs were favoured by N enrichment. N dose above 60kg enhanced the biomass of fast growing, erect, annuals, non N-fixers, nitrophilic HPTs. The changes in traits with N addition, especially the increase in annuals and grasses and decrease in typically N-rich N-fixers, have implications for sustainable cattle production. © The Author 2014. Published by Oxford University Press on behalf of the Institute of Botany, Chinese Academy of Sciences and the Botanical Society of China. All rights reserved.
Effect of nitrogen (N) deposition on soil-N processes: a holistic approach
(Nature Research, 2020) Preeti Verma; R. Sagar
Nitrogen (N) deposition is a serious environmental issue for soil fertility and human wellbeing. Studies on various terrestrial ecosystems yielded fragmented information on soil-N status (microbial biomass- and mineral-N) and dynamics (N-mineralization and -leaching) whereas the holistic view on this issue is relatively unknown. A complete understanding of soil-N status and dynamics in response to N deposition is essential for sustainable management of ecosystem structure and function as needed for human wellbeing. Therefore, we conducted an experiment in the N-limited tropical grassland to explore the question whether N-deposition weakens the soil-N status and dynamics; if yes, then what could be the optimum amount of deposited N and the related controlling mechanism? We undertook a 3-year (2013–2016) experimental N fertilization (control, 30, 60, 90, 120, and 150 kg N ha−1 year−1) study (using urea as a source of N deposition). The data from a total of 72, 1 × 1 m plots (six treatments with 12 replicates) were collected and properly analysed with statistical software. N deposition caused significant differences in the parameters of soil-N status and dynamics. The responses of microbial biomass-N, N-mineralization, and mineral-N to the N deposition were quadratic (maximum values were in N90) whereas N-leaching showed a linear response. Compared to control, N deposition (30–150 kg N) consistently enhanced (29–96%) leaching of N. As a mechanism, acidification induced aluminium toxicity, carbon to nitrogen ratio and litter decomposition governed the soil-N status and dynamics. N deposition over and above 90 kg ha−1 year−1 resulted in a negative feedback to soil N transformation and availability. Hence, N deposition below 90 kg ha−1 year−1 could be a limit for the sustainable functioning of the tropical or similar grasslands. © 2020, The Author(s).
Feedback of litter decay to temporal stability of biomass under N-inputs
(John Wiley and Sons Ltd, 2024) Preeti Verma; R. Sagar; Aakansha Pandey
Nitrogen (N) input affects litter decay and ecosystem functioning. However, the mechanism of litter decay under temporal N-inputs has rarely been observed. Here we show that three-year experimental N-inputs significantly stimulated the rate of litter decay to some extent and then inhibited it with increasing N-inputs. The N-inputs affected the litter's mass loss by directly influencing the temporal stability of aboveground biomass (BS) and diversity while indirectly changing soil pH, C: N ratio, and synergistic interactions of soil, vegetation, and microbial traits. The BS has emerged as a significant regulatory factor for the litter decay of tropical grassland. The outcome of the present study will be helpful in predicting the global feedback of litter decay on the N inputs and the amount of N required for the sustainable functioning of the degraded tropical or similar grasslands. © 2024 John Wiley & Sons Ltd.
Responses of diversity, productivity, and stability to the nitrogen input in a tropical grassland
(Ecological Society of America, 2020) Preeti Verma; R. Sagar
Atmospheric nitrogen (N) deposition is a matter of serious concern for the structure and functioning of global ecosystems, but the effect of N application of species diversity (D), primary productivity (P), and stability (S) of tropical grassland ecosystems is not known. The present study reports the effects of different levels of N application on species composition, and the D, P, S, and their relationships in a tropical grassland. Within the experimental grassland, 72 1 × 1 m plots with 6 N-input levels and with 12 replicates, were established in 2013. For 3 yr, different doses of urea as a source of N were applied to the plots. Data on individuals and biomass of each species were recorded and statistically analyzed. The study revealed that the N applied caused variations in species composition, D, P, and S. Below the 90 kg N dose, D was positively related to P and S while, above this level, the relations were negative due to N-induced responses of species and functional group composition as well as biomass distribution among them. The optimum applied N levels for maximum D (50–60 kg N), P (120 kg N), and a positive relationship of S with D (up to 90 kg N treatment) suggested that the 90-kg N dose could be the maximum dose of N that the grassland can tolerate. Hence, N application should not exceed the 90-kg level for sustainability of the structure and functioning of tropical grassland ecosystems. © 2019 by the Ecological Society of America
Soil physico-chemical properties, herbaceous species diversity and biomass in a nitrogen fertilization experiment
(CESER Publications, 2015) Punita Verma; R. Sagar; Preeti Verma; D.K. Singh; H. Verma
Nitrogen (N) deposition in biosphere due to anthropogenic activities and its consequences on soil and vegetation is a global issue. In this study, we ask: (i) Do N fertilizations affect soil elements, species diversity, biomass and productivity in a herbaceous vegetation? And (ii) Does heterogeneity in soil property enhances the species diversity and biomass in N addition experiment? In this study, 15 sites, each having nine 1x1m plots, were established in this study in the campus of Banaras Hindu University, India. These plots were equally categorized in three groups The plots of group one were kept as control, the plots of group two were treated with 60 kg N ha-1yr-1 and the plots of group three were treated with 120 kg N ha-1yr-1. The plots were continuously treated with urea fertilizer from year 2007. In years 2009 and 2010, for each treatment level, soil physico-chemical properties, herbaceous diversity, biomass and productivity were estimated using standard methods. The data were subjected to proper statistical analyses. Study indicated that continuous N treatment lowered the soil pH and increased the biomass and productivity. Moderate N dose (60 kg N ha-1 yr-1) experienced maximum diversity and heterogeneity in soil property. Further, results also suggested that under the condition of N treatments over several years, the spatial heterogeneity in soil property may support the herbaceous diversity and biomass for proper functioning of the ecosystems. © 2015, CESER Publications.
Soil respiration response to nitrogen fertilization experiment in tropical grassland
(John Wiley and Sons Inc, 2022) Preeti Verma; R. Sagar
We examined the response of soil respiration (SR) to nitrogen (N) input using a manipulation experiment in a tropical grassland. Studying the influence of N-input on the SR is important under sustainable agricultural strategies and future climate change. The response of SR is expected to vary in each ecosystem; therefore, manipulation experiments in many ecosystems and subsequent synthesis can be a significant strategy for climate change mitigation and adaptation. We hypothesized that the higher levels of N-input suppress the SR by reducing soil-C, species diversity, and biomass of the roots and microbes. For this study, seventy-two 1 × 1–m experimental plots (equally divided into six N-levels; each with 12 replicates) were established in 2013 on the campus of the Banaras Hindu University, India. On monthly basis, six levels of N (0, 30, 60, 90, 120, and 150 kg N ha−1 year−1) were applied to the plots. Soil and vegetation data were collected for 3 years and analyzed using statistical methods. The SR (mg m−2 h−1) ranged between 156 and 197 and significantly varied across the N-inputs. Analysis revealed 85 kg N ha−1 year−1 input is needed for the maximum SR because of higher contents of microbial biomass, soil-C, plant diversity, root biomass, and fast decomposition of the litters. The N-input beyond 85 kg ha−1 year−1 inhibited the SR due to N-induced soil acidification to the microbes and plants. We conclude that the SR of the tropical grassland ecosystem is synergistically governed by the N-input-modulated indirect effects of the soil and vegetation traits. © 2022 The Ecological Society of Japan.
Species diversity and temporal stabilization of root productivity of tropical grassland to nitrogen application
(Elsevier B.V., 2021) Preeti Verma; R. Sagar
Alarming rate of atmospheric nitrogen (N) deposition through massive uses of N-fertilizers has become a major issue for the sustainability of ecosystem structure and function. N manipulative studies in temperate regions have yielded debated responses of species diversity, root primary productivity, temporal stability of root primary productivity to the increasing N-inputs and these structural and functional attributes of the ecosystem may or may not be interlinked. There is a lacuna of such studies from tropical ecosystems and they are totally missing from the tropical grasslands which are receiving very high rate of N-fertilization and are facing unprecedented loss of biodiversity. The objectives of the present study were to explore the responses of diversity, root primary productivity, stability of root primary productivity (sustainable functioning of ecosystem) and their relationships to six levels of N-fertilization. Also, we tried to find out the optimal level of N-fertilization for sustainable functioning of the tropical grassland and to reveal the mechanism behind it. Within the experimental grassland, 72 1 × 1 m plots with 6 N-input levels (0, 30, 60, 90, 120 and 150 Kg N ha−1yr−1) each having 12 replicates, were established in 2013. For three consecutive years starting from 2013 to 2016, urea as a source of N was applied to the plots for simulating N-deposition. Data on individuals and root biomass of each species were seasonally recorded and statistically analysed. The diversity, root primary productivity and its stability significantly varied and quadratically responded to the N-fertilization doses. 90 Kg ha−1yr−1N fertilization yielded maximum primary productivity and its stability, whereas 60 Kg ha−1yr−1N-fertilization resulted in maximum diversity. Thus a moderate level of N application (90 kg ha−1 yr−1) appeared to be an optimum dose for stable functioning of the tropical grassland. Doses of N-fertilization beyond 90 Kg ha−1 yr−1 inhibited the sustainable ecosystem functioning because the substantially high N-fertilization resulted in increased soil acidity which enhanced soil-Al toxicity to the plant roots and loss of diversity. Nevertheless, further longer-term study could be needed for a more robust conclusion. © 2020 Elsevier Ltd
Species diversity-primary productivity relationships in a nitrogen amendment experiment in grasslands at Varanasi, India
(Indian Academy of Sciences, 2015) R. Sagar; Punita Verma; Hariom Verma; Dharmendra K. Singh; Preeti Verma
[No abstract available]
The response of soil organic carbon to nitrogen-induced multiple ecological attributes
(Springer Science and Business Media B.V., 2021) Preeti Verma; R. Sagar
Increasing concentrations of CO2 and reactive nitrogen (N) in the earth’s atmosphere are seriously threatening the human well-being. Globally, the response of SOC to the N application is inconclusive. Study reports the responses of SOCs to N application, species diversity (D), root primary productivity (RP), temporal stability of RP, soil-pH and soil-Al. Within experimental grassland at Varanasi, India, 72 1 × 1 m plots with 6N-input levels, and with 12 replicates, were established in 2013. For 3 years, different doses of urea as a source of N were applied to the plots. Data on above soil and vegetation variables were recorded and statistically analysed. The D, RP, TS, soil-pH, soil-Al and SOC significantly differed due to N application. Except the TS, each studied variable individually governed the SOC. The N fertilization modulated D, RP and soil-Al synergistically determined the SOC of the tropical grasslands. Below the 104–110 kg N-dose, the SOC showed positive response while above to this dose, it negatively responded. Thus, N application to the tropical grassland should not exceed 104–110 kg N; otherwise, N-induced ecological effects would be harmful to the sustainability of human well-being. © 2020, Springer Nature B.V.
Validation of carbon contents in different traits and components of herbaceous species from tropical grassland
(Ecological Society of India, 2020) Pratibha Chaturvedi; Preeti Verma; R. Sagar; Hariom Verma; Kuldeep Kumar
Because of global climate change events; the quantification of carbon (C) present in different species from diverse ecosystems are urgently needed. Study evaluated the performances of different methods used for the C estimation in different plant components and traits by comparing with harvest method. For this, 117 herbaceous species just-before flowering were harvested from the campus of Banaras Hindu University, Varanasi. Across the components, the mean C contents (g plant-1) varied between 0.33 for roots of procumbent and 7.93 for shoots of native trait categories. On g m-2 basis, it ranged from 29 (roots) to 85 (shoots). Similarly across the components, the mean C: B ratio ranged between 0.41 (roots) and 0.44 (shoots). The linear relationship between C and B had high correlation coefficient, low standard error of estimate together with low discrepancy in extrapolation compared to the other models. Hence, compared to other models, the linear equation could be used in C estimation. Further among all the estimators; at the species, component and functional group levels, the mean C: B (0.43) ratio of the entire herbaceous species resulted as an accurate estimator of the C. Because of its simplicity and low discrepancy, the mean C: B (0.43) ratio seems to be reasonable to estimate the C content based on the known biomass. Stems of perennials, erects, leguminous and native plants had greater C than the others. Thus, the perennial, erect, leguminous and native herbaceous species could be an alternative for reducing the atmospheric C in the tropical grasslands. © 2020 Ecological Society of India. All rights reserved.
Variations in N mineralization and herbaceous species diversity due to sites, seasons, and N treatments in a seasonally dry tropical environment of India
(2013) Punita Verma; Preeti Verma; R. Sagar
Nitrogen (N) is an essential element for plant growth, however enriched N deposition may have seriously impacts on air, water, soil and vegetations. In this reference, we assessed the impacts of N applications on the rates of N-mineralization and their counter effects on the composition and diversity of herbaceous vegetation in a seasonally dry tropical environment of India. For this; 135, 1×1m plots distributed in 15 locations were established at the Banaras Hindu University, India. Since 1st January 2007, within each location, equal numbers of 1×1m plots were treated with three doses of N (0kgNha-1yr-1/control, 60kgNha-1yr-1 and 120kgNha-1yr-1). Soil and vegetation samples were collected in year 2010. The data on soil N mineralization, rainfall and species numbers were collected monthly and the data on Shannon diversity index were collected seasonally. The data were subjected to appropriate statistical analyses. The NMS ordination suggested that the sites, N levels and seasons caused substantial differences in the rate of soil N-mineralization, species composition and diversity of herbaceous species. Results showed that moderate levels of rainfall and N applications (60kgNha-1yr-1) facilitated the accumulation of herbaceous species diversity by accelerating the process of soil N-mineralization due to increased availability of soil-N and decreased C:N ratio of the soil. The study did not support the N-saturation theory for the N-mineralization rates as well as species diversity possibly due to loss of added N through the process of volatization, denitrification and consumed by the nitrophilic species, which warrants in-depth study of microbial dynamics to explore the mechanisms associated with N mineralization in N perturbed ecosystems, particularly from dry tropical environments of India which are nutrient and moisture limited. © 2013 Elsevier B.V.
Variations in soil properties, species composition, diversity and biomass of herbaceous species due to ruminant dung residue in a seasonally dry tropical environment of India
(Centro Internacional de Agricultura Tropical (CIAT), 2015) Preeti Verma; R. Sagar; Nitu Giri; Ranjana Patel; Hariom Verma; D.K. Singh; Kuldeep Kumar
Ruminants directly or indirectly influence nutrient cycling and vegetation structure in grassland ecosystems. We assessed the impact of natural cattle dung deposition on soil attributes and the resulting effects on species composition, species diversity and biomass of herbaceous vegetation in a natural grassland in the seasonally dry tropical environ-ment of Banaras Hindu University, India. For this 72 plots of 1 × 1 m [12 locations × 2 treatments (dung residue and control) × 3 replicates] were selected in January 2013 and soil and vegetation samples collected. A total of 74 species belonging to 66 genera and 25 families were recorded. Principal Component Analysis (PCA) ordination revealed that the dung residue (DP) and control (CP) plots were distinctly different in terms of soil attributes and species composi-tion. The k-dominance plot showed greater species diversity in DPs than CPs, with higher soil nutrients and moisture and lower soil pH in DPs than CPs. Similarly, DPs showed more herbaceous species and greater biomass than CPs. This trend can be explained by the positive responses of forbs, erect plants, annuals, large-statured, non-native and non-leguminous species to dung residue, while increased biomass can be partly due to cattle preferentially not grazing areas adjacent to a dung pat. Overall, the study showed that deposition of dung during grazing by cattle stimulates growth of pasture species and increases species diversity. Therefore cattle dung could be used as a sustainable alterna-tive to chemical fertilizers to manage soil pH, species composition and diversity, and forage production in the season-ally dry tropical grasslands of India, which are nutrient- and moisture-limited. © 2015.
Variations of biomass and carbon contents in different traits and components of herbaceous species from tropical grassland
(African Science Publications, 2019) Preeti Verma; R. Sagar; Hariom Verma; Abhishek Rai; Pratibha Chaturvedi; Prem Pratap Singh; Kuldeep Kumar; Sandeep Kumar Singh
Grasslands play a critical role in the global storage of atmospheric carbon (C). Precise estimation of C contents in different plant components is essential to formulate a strategy for mitigating the atmospheric C. Biomass (B) and C of different herbaceous plant components at species, functional group and site levels from tropical grassland locating on the campus of Banaras Hindu University, Varanasi, India were estimated. For this; 117 herbaceous species just-before flowering were harvested. B and C contents for each species and component were measured and statistically analyzed. The measured C (g plant-1) across the components varied from 0.08 to 31.12. On gm–2 basis; it varied between 29 (leaf) and 49 (root). Plant components, species and functional groups in isolation caused significant differences in the measured C. In the present study; the C content of stem was greater than the leaf and root. The perennial, erect, leguminous and native traits had greater C than the others. Therefore, this observation revealed that the perennial, erect, leguminous and native plants could be a better option for reducing the atmospheric CO2 by capturing it and then converting into B through photosynthesis. Further, the fitted regression equation between the root and shoot for B and C could be used for the extrapolation of B and C of the root component based on the shoot component. The conservative field measurement methods may give precise data on B and C but are destructive to grassland, difficult, time-consuming, and costly to cover at large scale. Hence, the present work could be substantial for the estimation of root C based on shoot component. © 2019 African Journal of Biological Sciences. All rights reserved.