Browsing by Author "Sonu Singh"

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Agroecological responses of heavy metal pollution with special emphasis on soil health and plant performances
(Frontiers Media S.A., 2017) Vaibhav Srivastava; Abhijit Sarkar; Sonu Singh; Pooja Singh; Ademir S.F. de Araujo; Rajeev P. Singh
With modern day urbanization and industrialization, heavy metal (HM) contamination has become a prime concern for today's society. The impacts of metal contamination on agriculture range from the agricultural soil to the produce in our food basket. The heavy metals (HMs) and metalloids, including Cr, Mn, Co, Ni, Cu, Zn, Cd, Sn, Hg, Pb, among others, can result in significant toxic impacts. The intensification of agricultural land use and changes in farming practices along with technological advancement have led to heavy metal pollution in soil. Metals/metalloids concentrations in the soil are increasing at alarming rate and affect plant growth, food safety, and soil microflora. The biological and geological reorganization of heavy metal depends chiefly on green plants and their metabolism. Metal toxicity has direct effects to flora that forms an integral component of ecosystems. Altered biochemical, physiological, and metabolic processes are found in plants growing in regions of high metal pollution. However, metals like Cu, Mn, Co, Zn, and Cr are required in trace amounts by plants for their metabolic activities. The present review aims to catalog major published works related to heavy metal contamination in modern day agriculture, and draw a possible road map toward future research in this domain. © 2017 Srivastava, Sarkar, Singh, Singh, de Araujo and Singh.
An insight to atmospheric pollution- Improper waste management and climate change nexus
(Springer International Publishing, 2017) Bhavisha Sharma; Barkha Vaish; Vaibhav Srivastava; Sonu Singh; Pooja Singh; Rajeev Pratap Singh
Urbanization and industrialization along with expansion of the cities, extract resources indiscriminately in order to provide better access to food security, education, health and employment. However, accompanying this urbanization and industrialization, there is an increase in generation of vast amount of waste. Per capita waste generation is closely related to high quality life style, consumer pattern and economic development. Municipal Solid Waste (MSW) is affected by many drivers (socio-economic, political, environmental, etc.) and its impact differs from country to country. The scenario is worse and complicated in developing countries due to negligence in waste management sector. Improper waste management has emerged as one of the potent source of series of air pollutants that arises concerns over ambient air quality, environmental degradation and public health. Overall waste sector is estimated to contribute around 3-5% of global greenhouse emission. But, this estimate does not include the emission from the uncollected waste that decays anaerobically and is the main cause of methane generation which has not yet been quantified. Therefore, it is imperative to integrate proper waste management technologies especially for developing economies. Thus, this chapter attempts to relate the nexus between improper management of municipal solid waste and climate change and to reduce greenhouse gas emissions through proven technologies and existing policies. © Springer International Publishing AG 2018.
Influence of resource quality of organic inputs on rice-barley dryland agro-ecosystem: Variations in biological productivity, grain yield and efficiency of nitrogen use
(2007) Sonu Singh; Nandita Ghoshal; K.P. Singh
A two-year study was undertaken in a tropical dryland agro-ecosystem to evaluate the effect of the application of soil amendments with contrasting chemical natures on crop productivity, grain yield, N-uptake and N-use efficiencies. The treatments involved the addition of equivalent amounts of N (80 kg N ha-1) through chemical fertilizer and three organic inputs at the beginning of the annual cycle: Sesbania aculeata shoots (high quality, C/N 16), wheat straw (low quality, C/N 82) and Sesbania+wheat straw (high and low quality combined, C/N 47), together with a control treatment. Test crops consisted of an annual sequence of rice and barley, sown in the rainy and winter seasons, respectively. Fertilizer and Sesbania inputs resulted in higher total net productivity (TNP) for the rice crop (47 % and 32 % increases over the control, respectively) than the combined (+28 %) and wheat straw treatments (+10 %). During the succeeding barley crop, maximum TNP was recorded in the Sesbania+wheat straw treatment (+52 %), followed by wheat straw (+43 %), fertilizer (+19 %) and Sesbania (+17 %). The TNP and grain yields of both crops added together were higher in Sesbania+wheat straw and fertilizer treatments compared to a single applications of either Sesbania or wheat straw. The Sesbania+wheat straw and fertilizer treatments resulted in more efficient utilization of N compared to the other treatments. Crop roots played a pivotal role in N-recovery from the soil and their N concentrations differed significantly (p < 0.05) due to the application of soil amendments. Across different treatments, crop root biomass was strongly correlated with crop N-uptake (r = 0.81, n = 10, p < 0.05), recovery efficiency (r = 0.81, n = 8, p < 0.05) and agronomic efficiency (r = 0.81, n = 8, p < 0.05). It is suggested that the combined application of high and low quality resources modulated N release, resulting in relatively higher productivity through the annual cropping cycle. Such combined inputs may prove useful in developing low input, environment friendly soil management practices in tropical dryland agro-ecosystems. © 2007 Cambridge University Press.
Microbes-assisted remediation of metal polluted soils
(Elsevier, 2019) Bhavisha Sharma; Pooja Singh; Puneet Singh Chauhan; Sonu Singh; Rajeev Pratap Singh
The rapid increase in urbanization and industrial growth has led to the exploitation and pollution of valuable natural resources like soil and water. Soil pollution due to the toxic heavy metals, hazardous chemicals, and consequential contamination of groundwater, sediments, surface water, and food chain is one of the major environmental concerns of the modern era. Metal contamination of soil occurs due to the release of metals in the environment from several anthropogenic activities such as agriculture, disposal of urban and industrial wastes, mining, smelting, and various other industrial operations. Metals when present in higher concentration show phytotoxicity in plants and cause serious health issues in human beings due to their carcinogenic and mutagenic nature. Since metal pollution has serious implications for food safety, health, and environment, bioremediation of metal-contaminated soils using microorganisms can be explored as a promising approach toward a sustainable and eco-friendly mitigation of this problem. Microbes remediate heavy metals through different mechanisms such as redox reaction, bioprecipitation, extracellular complexation, and intracellular accumulation. Bioremediation, being a low cost, green, and environment-friendly option as compared to the conventional physicochemical remediation methods can play a pivotal role in the development of future remediation technologies. This chapter aims to highlight the current status, challenges, and opportunities in the bioremediation of heavy metals from contaminated soils. © 2019 Elsevier B.V. All rights reserved.
Preventing Microplastic Pollution in Surface Waters: Legal Frameworks and Strategic Actions
(John Wiley and Sons Inc, 2025) Monika Mahajan; Ajay Kumar Singh; Rajeev Pratap Singh; Pankaj Kumar Gupta; Sonu Singh; Mayank Pratap
Microplastic contamination of surface water is another looming environmental issue driven by fast industrialization, urbanization, and the rampant use of plastics. Microplastics are plastic particles smaller than 5 mm in size, and there are a variety of origins, including broken pieces of plastic waste, synthetic fibers, or industrial effluents. They are one of the pollutants that pose significant threats to aquatic ecosystems and human well-being because they carry toxic substances, disrupt aquatic food webs, and degrade water quality. This situation led India to formulate a series of regulatory frameworks for the reduction of plastic pollution. Other important policies are the 2016 Plastic Waste Management Rules, with a focus on recyclability and reduction of plastic waste at the source level, and the 2022 countrywide single-use plastic ban, which targets the spread of high-volume plastics that lead to microplastic pollution. India also works with international groups like the Global Partnership on Marine Litter and has integrated EPR into its plastic waste management to make it more long-lasting. In some states, incomplete or nonexistent waste management infrastructure and a lack of specific legislation on microplastics combine to raise concerns about enforcement. This review discusses the source and implications of microplastic contamination in the surface water, evaluates the effectiveness of the current legal regime, and highlights what could be done to strengthen the legislation and reduce microplastic contamination. Strengthened surveillance, state-of-the-art wastewater treatment technology, and awareness programs are essential before such elements can prevent the entry of microplastic contaminants and protect water bodies. © 2025 Wiley Periodicals LLC.
Reclamation of degraded land through forestry practices
(Nova Science Publishers, Inc., 2012) Rajeev Pratap Singh; Sonu Singh; Anita Singh; Puneet Singh Chauhan
During the past few decades, global population is increasing at an exponential rate. As a consequence of that, more productive areas are needed to fulfill the increasing demand of food, fiber, livelihood and other important ecosystem services. On the contrary, due to various measures, degradation of effective and productive landmasses has been seriously increased, and become a burning issue at presently worldwide. Different socio-economic challenges (e.g. population burst, uncontrolled urbanization, improper resource management etc.) and environmental challenges (e.g. climate change, soil erosion etc.) are constantly imposing threats to land quality. The only way to survive under these increasing multidimensional challenges to restore the degraded land mass through sustainable practices. Several studies have proven that proper agro-forestry practices can check soil erosion to some extent; increase soil fertility; reduce salinity, alkalinity, acidity and desertification, etc. This chapter mainly demonstrates the significant causes and types of land degradation for possible sustainable restoration strategies using forestry practices and their potential benefits effects on environment. © 2012 Nova Science Publishers, Inc. All rights reserved.
Soil carbon dioxide flux, carbon sequestration and crop productivity in a tropical dryland agroecosystem: Influence of organic inputs of varying resource quality
(2009) K.P. Singh; Nandita Ghoshal; Sonu Singh
In view of the significance of agricultural soils in affecting global C balance, the impact of manipulation of the quality of exogenous inputs on soil CO2-C flux was studied in rice-barley annual rotation tropical dryland agroecosystem. Chemical fertilizer, Sesbania shoot (high quality resources), wheat straw (low quality resource) and Sesbania + wheat straw (high + low quality), all carrying equivalent recommended dose of N, were added to soil. A distinct seasonal variation in CO2-C flux was recorded in all treatments, flux being higher during rice period, and much reduced during barley and summer fallow periods. During rice period the mean CO2-C flux was greater in wheat straw (161% increase over control) and Sesbania + wheat straw (+129%) treatments; however, during barley and summer fallow periods differences among treatments were small. CO2-C flux was more influenced by seasonal variations in water-filled pore space compared to soil temperature. In contrast, the role of microbial biomass and live crop roots in regulating soil CO2-C flux was highly limited. Wheat straw input showed smaller microbial biomass with a tendency of rapid turnover rate resulting in highest cumulative CO2-C flux. The Sesbania input exhibited larger microbial biomass with slower turnover rate, leading to lower cumulative CO2-C flux. Addition of Sesbania to wheat straw showed higher cumulative CO2-C flux yet supported highest microbial biomass with lowest turnover rate indicating stabilization of microbial biomass. Although single application of wheat straw or Sesbania showed comparable net change in soil C (18% and 15% relative to control, respectively) and crop productivity (32% and 38%), yet they differed significantly in soil C balance (374 and -3 g C m-2 y-1 respectively), a response influenced by the recalcitrant and labile nature of the inputs. Combining the two inputs resulted in significant increment in net change in soil C (33% over control) and crop yield (49%) in addition to high C balance (152 g C m-2 y-1). It is suggested that appropriate mixing of high and low quality inputs may contribute to improved crop productivity and soil fertility in terms of soil C sequestration. © 2009 Elsevier B.V. All rights reserved.
Soil physicochemical properties in a grassland and agroecosystem receiving varying organic inputs
(2009) Sonu Singh; Ritu Mishra; Alka Singh; Nandita Ghoshal; K.P. Singh
The application of organic amendments in agroecosystems has been widely recommended, but the impact of their C/N ratio on the stabilization and sequestration of soil organic carbon (SOC) is often unaccounted for. The influence of the C/N ratio of amendments on soil physicochemical properties in a rice (Oryza sativa var. NDR97)-barley [Hordeum vulgare var. Lakhan) rotation tropical dryland agroecosystem was compared with an undisturbed grassland. Chemical fertilizer in the form of urea and three organic inputs (Sesbania aculeata shoot, low C/N ratio; air-dried straw of wheat [Triticum aestivum var. Malviya 533), high C/N ratio; and S. aculeata shoot+wheat straw, high and low C/N ratio combined) carrying an equivalent amount of N, were added to plots of the agroecosystem once during each annual cycle. Soil water-holding capacity (WHC), porosity, SOC, total N, and aggregate stability were improved in the wheat straw and S. aculeata shoot+wheat straw treatments, reaching levels comparable with the grassland. Soil WHC, porosity, and SOC influenced the productivity of the grassland and the agroecosystem. The grassland recorded highest SOC (53% higher relative to control) followed by the wheat straw (+47%), S. aculeata shoot+wheat straw (+37%) and soil total N was greatest in the S. aculeata shoot+wheat straw treatment (+37.5%). Aggregate stability and macroaggregate distribution were also higher in the wheat straw and S. aculeata shoot+wheat straw treatments, however, the microaggregate and silt + clay fractions showed a reverse trend. Management practices with a higher residue-C return in the agroecosystem resulted in increased aggregate stability and aggregate-associated SOC, with C storage attaining levels similar to the natural system. © Soil Science Society of America.
Synchronizing nitrogen availability through application of organic inputs of varying resource quality in a tropical dryland agroecosystem
(2007) Sonu Singh; Nandita Ghoshal; K.P. Singh
A 2-year field experiment was conducted to evaluate the impact of management practices involving manipulation of quantity and quality of exogenous inputs on soil N-mineralization rate, N availability and microbial biomass in a rice-barley rotation in a tropical dryland agroecosystem. At the beginning of each annual cycle an equivalent amount of N was added through chemical fertilizer and three organic inputs: Sesbania shoot (high quality resource, C/N 16, lignin/N 3.2, polyphenol + lignin/N 4.2), wheat straw (low quality resource, C/N 82, lignin/N 34.8, polyphenol + lignin/N 36.8) and Sesbania + wheat straw (high and low quality resources mixed). The N-mineralization rate was dominated by ammonification in this dryland agroecosystem. N-mineralization exhibited a distinct seasonal pattern, decreasing from the rice period through the summer fallow period, except in Sesbania + wheat straw and wheat straw treatments which showed a slight increase during the early stages of barley period. The rate of N-mineralization showed a significant relationship with soil moisture and microbial biomass N. During the rice period, N-mineralization rate and available-N was highest in the fertilizer treatment followed by Sesbania > Sesbania + wheat straw > wheat straw. During the barley period, highest N-mineralization rate and available-N was observed in Sesbania + wheat straw followed by wheat straw > Sesbania > fertilizer. Adding Sesbania + wheat straw resulted in consistently higher levels of microbial biomass N, N-mineralization rate and available-N through the annual cycle compared to single application of Sesbania and wheat straw, indicating synergy between the two inputs, favoring more efficient utilization of N. It is suggested that mixed application of high and low quality resources can modulate N release, resulting in relatively higher synchronization which can help in minimizing N loss from agroecosystem. © 2007.
Variations in soil microbial biomass and crop roots due to differing resource quality inputs in a tropical dryland agroecosystem
(2007) Sonu Singh; Nandita Ghoshal; K.P. Singh
The influence of exogenous organic inputs on soil microbial biomass dynamics and crop root biomass was studied through two annual cycles in rice-barley rotation in a tropical dryland agroecosystem. The treatments involved addition of equivalent amount of N (80 kg N ha-1) through chemical fertilizer and three organic inputs at the beginning of each annual cycle: Sesbania shoot (high-quality resource, C:N 16, lignin:N 3.2, polyphenol+lignin:N 4.2), wheat straw (low-quality resource, C:N 82, lignin:N 34.8, polyphenol+lignin:N 36.8) and Sesbania+wheat straw (high-and low-quality resources combined), besides control. The decomposition rates of various inputs and crop roots were determined in field conditions by mass loss method. Sesbania (decay constant, k=0.028) decomposed much faster than wheat straw (k=0.0025); decomposition rate of Sesbania+wheat straw was twice as fast compared to wheat straw. On average, soil microbial biomass levels were: rice period, Sesbania≥Sesbania+wheat straw>wheat straw≥fertilizer; barley period, Sesbania+wheat straw>Sesbania≥wheat straw≥fertilizer; summer fallow, Sesbania+wheat straw>Sesbania>wheat straw≥fertilizer. Soil microbial biomass increased through rice and barley crop periods to summer fallow; however, in Sesbania shoot application a strong peak was obtained during rice crop period. In both crops soil microbial biomass C and N decreased distinctly from seedling to grain-forming stages, and then increased to the maximum at crop maturity. Crop roots, however, showed reverse trend through the cropping period, suggesting strong competition between microbial biomass and crop roots for available nutrients. It is concluded that both resource quality and crop roots had distinct effect on soil microbial biomass and combined application of Sesbania shoot and wheat straw was most effective in sustained build up of microbial biomass through the annual cycle. © 2006 Elsevier Ltd. All rights reserved.