Papers by RISHIKESH SINGH
Energy, Ecology and Environment, 2016
The management of soil organic carbon (
Ecological Indicators, 2016
Energy, Ecology and Environment, 2016
Ecological Indicators, 2016
: Comparative study of dye degradation using TiO 2 -activated carbon nanocomposites as catalysts ... more : Comparative study of dye degradation using TiO 2 -activated carbon nanocomposites as catalysts in photocatalytic, sonocatalytic, and photosonocatalytic reactor, Desalination and Water Treatment,
In the present study reduced graphene oxide based composite with TiO2 were used as photocatalyst ... more In the present study reduced graphene oxide based composite with TiO2 were used as photocatalyst for degradation of BTEX compounds in photochemical reactor. Graphene oxide−TiO2 nanocomposites with carbon loadings were synthesized by hydrothermal method. Temperature of reactor was controlled by water flow. The prepared catalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray diffractometry (XRD) and Raman spectroscopy (RS). Degradation of petrochemical waste water was estimated by gas chromatography (GC). The Photo-catalytic efficiencies of the synthesized composites were determined by the degradation of petrochemical waste water (BTEX) under UV irradiation in photochemical reactor. Thus, in photo degradation of petrochemical waste (BTEX compound), a significant enhancement in the degradation rate was observed with graphene oxide-TiO2 nanocomposite, as compared to bare TiO2 and graphene under similar condition. This approach can be further used for degradation of other recalcitrant organic pollutant.
Surplus crop residue generated from different cereal crops and their open burning leading to seve... more Surplus crop residue generated from different cereal crops and their open burning leading to several environmental anomalies are of serious concern, though worldwide but more in developing nations. Residue retention under conservation agriculture strategy is one of the suggested alternatives; however, it is not yet succeeded well in tropical regions due to higher rate of decomposition. Fast release of photo-synthetically locked atmospheric CO 2 to the atmosphere is a major constraint for this strategy. Therefore, instead of earlier complete residue retention or 'slash and burn' approaches, recently 'slash and char' strategy is being promoted for agricultural residue management as well as climate change mitigation in developed countries. However, complete slash and char approach may lead to loss of various ecosystem services provided by crop residue such as soil erosion control and soil physical management. Recently, research is progressing towards biochar-residue integrated approach under conservation agriculture systems. In the present study, we are emphasizing on the judicious use of crop residue and its biochar in integrated manner for agricultural sustainability.
The complex interaction between nitrogen (N) availability and soil organic carbon (SOC) dynamics ... more The complex interaction between nitrogen (N) availability and soil organic carbon (SOC) dynamics in the nutrient-limited dry tropical agroecosystem requires investigation in the changing climatic conditions. Organic amendment shows a direct linkage between nutrient availability and SOC dynamics, and improves SOC by mediating soil physicochemical and biological properties. Therefore, plots under various ages of organic cultivation (viz., organic plots under one (O1), three (O3), five (O5) and ten (O10) years) along with nearby native forest ecosystem (REF) were taken in this study to explore the linkage between the nutrient availability and SOC dynamics. Soil moisture content (SMC), soil temperature, SOC, soil carbon efflux (SCE), microbial biomass carbon (MBC), soil ammonium-N (NH4+-N) and nitrate-N (NO3−-N) were investigated. SMC showed positive (power and linear) while the soil temperature showed polynomial (quadratic) relationship with SCE. Interestingly, the soil temperature and SMC also showed contrasting relationships with the soil ammonium-N:nitrate-N ratio (ANR) in the summer season. Further, the ANR was also observed to indirectly govern SOC by affecting MBC and SCE, particularly in summer. It suggests that the long term organic amendment indirectly sequesters SOC by moderating SCE, through increase in the ANR, possibly by affecting the microbial community associated with nitrification. Therefore, consideration of the ANR in SOC management assessment in the dry tropical agroecosystem, owing to its significant coverage and C-sink potential, may help to mitigate the rapidly increasing, CO2-induced global climate change. It also indicates that the organic amendments may potentially nullify the predicted positive climate change-carbon cycle feedback. Thus, inclusion of the ANR in climate models may better predict the future course of climate.
Lignocellulosic crop residue biomass, in surplus, is of vital importance due to its multifaceted ... more 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 agrochemical...
Ecological Engineering, 2015
Lignocellulosic crop residue biomass, in surplus, is of vital importance due to its multifaceted ... more 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 byproduct 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.
Environmental Monitoring and Assessment, 2015
Multivariate statistical techniques were employed for monitoring of ground-surface water interact... more Multivariate statistical techniques were employed for monitoring of ground-surface water interactions in rivers. The river Varuna is situated in the Indo-Gangetic plain and is a small tributary of river Ganga. The study area was monitored at seven sampling sites for 3 years (2010-12), and eight physio-chemical parameters were taken into account for this study. The data obtained were analysed by multivariate statistical techniques so as to reveal the underlying implicit information regarding proposed interactions for the relevant area. The principal component analysis (PCA) and cluster analysis (CA), and the results of correlations were also studied for all parameters monitored at every site. Methods used in this study are essentially multivariate statistical in nature and facilitate the interpretation of data so as to extract meaningful information from the datasets. The PCA technique was able to compress the data from eight to three parameters and captured about 78.5 % of the total variance by performing varimax rotation over the principal components. The varifactors, as yielded from PCA, were treated by CA which grouped them convincingly into three groups having similar characteristics and source of contamination. Moreover, the loading of variables on significant PCs showed correlations between various ground water and surface water (GW-SW) parameters. The correlation coefficients calculated for various physiochemical parameters for ground and surface water established the correlations between them. Thus, this study presents the utility of multivariate statistical techniques for evaluation of the proposed interactions and effective future monitoring of potential sites.
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Papers by RISHIKESH SINGH