خيارات البحث
النتائج 221 - 230 من 7,214
Numerical Simulation of Soil Temperature With Sand Mulching During the Growing Season of Spring Wheat
2022
Wenju Zhao, Yuhang Liu, Zongli Li | Yu Su
The thermal conditions of soil are important in practical agricultural production. The characteristics of heat flux, moisture content, thermal conductivity, and other soil parameters vary with temperature. This study uses VADOSE/W to create a model of heat transmission between soil and atmosphere, simulating daily changes in soil temperature using sand mulching. By using the published data to verify the model, the results show that the fitting effect is good and the reliability of the model is verified. We also used this model to determine the temporal and spatial distributions of soil temperature, temperature differences, and a temperature gradient for sand mulching and bare soil during the growing season of spring wheat. These results indicated that the sand mulching preserved heat at night. The difference in temperature at each depth and the temperature gradient became negative with the gradual increase in solar altitude. The difference in soil temperature at each depth and the temperature gradient tended to become positive by 22:00. These results indicated that the sand mulch effectively maintained the soil temperature in the morning and night during the growing season and impeded the transfer of heat at mid-day. This study provides a new method for determining the transfer of heat in sand-mulched soil, which can guide the effective regulation of soil temperature.
اظهر المزيد [+] اقل [-]Photosynthetic Microorganisms Consortium as Bioindicators for Heavy Metals
2022
N. A. Khishamuddin, L. S. Wong, M. K. Chai | G. Subramaniam
Heavy metals that are discharged through industrial and agricultural activities cause contamination, especially to the water sources, and bring about negative impacts on the flora and fauna in the ecosystem. The monitoring of heavy metals in the environment requires high technical skills with sophisticated equipment and is also time-consuming. In this study, the potential of using natural photosynthetic microorganism consortiums collected from natural water bodies as bioindicators for the screening of heavy metals was explored. The photosynthetic microorganism consortiums were first cultured in lab, immobilized, and then exposed to different heavy metals (Cd, Cu, Ni and Co) at different concentrations (0.01 mg.L-1, 0.05 mg.L-1, 0.10 mg.L-1, 0.50 mg.L-1, 1.00 mg.L-1 and 5.00 mg.L-1). The fluorometric responses before and after the exposure to heavy metals were measured. The results revealed that consortium cells responded to a wide range of heavy metals within a short period of exposure. The responses showed that the consortium cells can detect the presence of Cd, Cu, Ni, and Co within the range of 0.05-5.00 mg.L-1. The study confirmed that the photosynthetic microorganism consortiums collected from natural water bodies could be used as bioindicators for the screening of heavy metals.
اظهر المزيد [+] اقل [-]Geochemical Characteristics and Geological Significance of Cassiterite in the Dalong Tin Deposit, Baoshan Block, SW China
2022
Chuanyu Zhang, Wanting Li, Haijun Yu, Yingxiang Lu, Jianze Sha | Shusheng Yang
The Dalong tin deposit, located in the Luziyuan polymetallic ore field of the southern Baoshanblock, Southwest China, is composed of lenticular and bedded orebodies hosted in a Cambrianslate-marble sequence. As the only tin deposit in the orefield, the genesis of the Dalong deposit isof great significance to the understanding of regional metallogenic regularity. Based on a systematicfield survey and petrographic observation, EPMA and LA-ICP-MS major/trace element analyses ofcassiterite were carried out in this study. The enrichment of Fe, W, and Ti in cassiterite, as well as thedepletion of Nb, Ta, and Mn, reveal cassiterite’s features in granitic magmatic-hydrothermal deposits.The Dalong deposit can be categorized as a magmatic-hydrothermal vein-type deposit because of itssulfur isotopic properties, and the main sources of ore-forming fluid and minerals are thought to beburied intermediate-acid intrusions in the mining area’s depths.
اظهر المزيد [+] اقل [-]Impressions of Coastal Communities on Climate Change and Livelihood: A Case Study of Coastal Maharashtra, India
2022
Ravi Sharma, Shrishti Jagtap | Prakash Rao
The socio-economic and institutional systems of a developing country like India have a big role in the effects of perception on the choice of adapting capability. The study uses exploratory factor analysis to better understand these implications in a regional context (EFA). Therefore, survey research is carried out in Sindhudurg district of coastal Maharashtra, with 410 respondents, assessing perception. EFA leads to the unpacking of latent constructs evaluating the perception of climate change, which in turn affects adaptive capacity and livelihood resilience. These constructs are biophysical impact cognition, motivation to change, economic diversification, and adaptive skills, which together account for 50% of coastal fishermen’s perception of climate change. Multivariate analysis of variance (MANOVA) revealed differences in the interpretation of these factors among coastal fishermen from various backgrounds (MANOVA). Overall, the research emphasizes the importance of perception in determining adaptive choices and resilience. According to the findings, developing adaptation-friendly infrastructural areas is recommended for society’s resilient functioning.
اظهر المزيد [+] اقل [-]Abrasion and Accretion Analysis in Demak, Indonesia Coastal for Mitigation and Environmental Adaptation
2022
A. Irsadi, N. K. T. Martuti, M. Abdullah | L. N. Hadiyanti
The purpose of this study was to analyze abrasion at the border of Sayung, Demak, Indonesia. Coastal abrasion data were obtained from high-resolution images from 2005-to 2017 by using ArcGIS 10.3, while data on environmental factors that affected abrasion, including tides from 2013-to 2017, was obtained from BMKG. Based on the analysis and calculations, the area of abrasion at the coast of Sayung, Demak was 262.74 hectares spread over four villages, namely Sri Wulan, Bedono, Timbulsloko, and Surodadi. Avifauna in the mangroves will be severely harmed by abrasion. As a result, abrasion prevention and evaluation, as well as the factors that cause abrasion, are required to reduce the impact of abrasion on the specified shore.
اظهر المزيد [+] اقل [-]Study on the Effects of Organophosphate Insecticide Triazophos, Biopesticide Spinosad and a Pyrethroid Insecticide Cypermethrin on Oxidative Stress Biomarkers of Branchiura sowerbyi (Beddard, 1892)
2022
Chandan Sarkar, Arnab Chatterjee, Anandamay Barik | Nimai Chandra Saha
This study aims to evaluate the toxic effects of organophosphate insecticide triazophos, biopesticide spinosad, and a pyrethroid insecticide cypermethrin on benthic Oligochaete worm, Branchiura sowerbyi during 96 h acute exposure. B. sowerbyi were exposed to two different sub-lethal concentrations (10% and 50% of 96h LC50) of triazophos, spinosad, and cypermethrin for 96 h in laboratory conditions. Catalase (CAT) activity of the control and treated worms were evaluated after 24 and 96 h of exposure. Integrated biomarker response (IBR) was applied for comparison between these three toxicants. For all sub-lethal doses i.e. 2.25 mg.L-1 and 0.5 mg.L-1 of test chemical triazophos, 3.07 mg.L-1 and 0.6 mg.L-1 of test chemical spinosad, and 0.38 mg.L-1 and 0.08 mg.L-1 of test chemical cypermethrin, catalase (CAT) activity raised significantly (p<0.05) in the treated worms in compare to the control worms. This study shows that toxicants including Triazophos, spinosad, and cypermethrin cause a large increase in catalase (CAT) activity in Branchiura sowerbyi, which is likely due to the toxicant’s increased ROS creation neutralizing the negative effects. IBR analysis aids in the differentiation of these three compounds’ harmful effects. As per IBR analysis, the rank of the toxicants is Cypermethrin > Triazophos > Spinosad.
اظهر المزيد [+] اقل [-]Water Quality Evaluation and Spatiotemporal Variation Characteristics of Wenyu River Based on Comprehensive Water Quality Identification Index Method
2022
Wang Keke, Men Baohui | Xing Yanling
In recent years, the water environment management of the Wenyu River has yielded positive outcomes. In comparison to earlier, the general water quality has substantially improved. However, some areas’ water quality has not improved as a result of the overall trend of improvement, which has implications for the surrounding areas and the entire water environment. To further explore the water environmental quality of specific river sections, this paper adopts the five monitoring sections of Shahe Gate, Mafang, Lutuan Gate, Xinbao Gate, and the additional sewage outlet in 2019, and the three main water quality indicators of COD, DO, and NH3-N. The water quality of the Wenyu River was evaluated using the comprehensive water quality identification index method, and the characteristics of its temporal and spatial changes were studied using correlation analysis and spatial clustering. The results have shown that the Wenyu River is generally Grade V water during the flood season, and is inferior to Grade V water during the non-flood season. All indicators have a regular time and space distribution and are highly influenced by environmental and human factors. Overall, the water quality of the Wenyu River may essentially reach the water environment function zoning target value. Improvements to the river portions below the Xinbao sluice, as well as the use of rainwater resources, must be prioritized.
اظهر المزيد [+] اقل [-]Assessment of Growth Promoting Ability of Three Cyanobacterial Isolates Under Sewage Water Irrigation
2022
Lalita Rana | Rajesh Dhankhar
Heavy metal pollution from the increased use of sewage effluent for irrigation is posing a hazard to agricultural ecosystems. Thus, a reliable and simple method of reducing the impact of heavy metals on plant growth is required. In the present study, cyanobacterial species were isolated from the sewage water irrigated soil of Rohtak city, Haryana, India, and characterized by various biochemical parameters. The cyanobacterial filtrates were then used to analyze their effects on the growth performance of rice seedlings under various concentrations of sewage wastewater. The results revealed a statistically significant increase in biomass, photosynthetic pigments, nitrate reductase activity, plumule, and radical length of rice seedlings by application of cyanobacterial filtrates. The antioxidant system (peroxidase enzyme and catalase enzyme activity) was also found to be stimulated. As compared to introduced species, the extracts of isolated species had a more favorable, statistically significant effect on rice seedlings. Our study indicated that these isolates have a high tolerance against heavy metals and are potentially useful as biofertilizers for the crops in sewage water irrigated agroecosystems.
اظهر المزيد [+] اقل [-]Traffic Noise Pollution Assessment in Major Road Junctions of Imphal City, Manipur (India)
2022
Ramtharmawi Nungate | Wazir Alam
Noise pollution assessment was carried out in selected traffic junctions of Imphal city of Manipur, India,using noise parameters and indices such as L10, L50, L90, Leq for the different periods of the day, i.e.,morning, noon, and evening hours. The study of equivalent noise level (Leq), noise parameters, andvarious noise indices have enabled the evaluation of the overall traffic noise environment of the city.The noise indices such as traffic noise index (TNI), noise climate (NC), traffic noise pollution level (LNP),noise exposure index (NEI) along with day time (LD), night time (LN) average, and day-night (Ldn) noiselevels were assessed for the selected traffic junctions. Moreover, spatial noise mapping was carriedout using the geostatistical interpolation technique to evaluate the changes of traffic noise scenariosduring the different time zones of the day. The Leq values in a few traffic junctions exceeded the requirednoise standards. The study shows equivalent noise levels ranging between 52.2-69.9 dB(A) duringthe morning (7-10 am), 52.4 -69.3 dB(A) during noon (12 noon-2 pm), and 54.6-71.1 dB(A) during theevening (4-7 pm) hours, respectively.
اظهر المزيد [+] اقل [-]Analyzing the Efficacy of Salvinia molesta Mitchell as Phytoremediation Agent for Lead (Pb)
2022
F. Rachmadiarti, G. Trimulyono | W. H. Utomo
Heavy metals, especially Pb (lead), are generally toxic to living things. Pb can contaminate organisms in the water through the food chain. The purpose of this study is to enhance water quality by using Salvinia molesta to phytoremediate Pb-polluted water. This study aims to evaluate the ability of S. molesta as a Pb phytoremediator. We evaluated total protein, free amino acids produced by the plant, and plant growth (dry biomass). S. molesta was grown in a hydroponic system exposed to Pb at dosages of 0, 5, 10, and 15 ppm for 7 and 14 days. Pb level was analyzed using Atomic Absorption Spectrophotometer and amino acids were analyzed using High-Pressure Liquid Chromatography. Data were statistically analyzed using analysis of variance (ANOVA) followed by Tukey’s test (α < 0.05). Results showed a significant change in Pb content in the roots and leaves of Pb-exposed S. molesta Mitch compared to control. In Pb-exposed plants, total protein and amino acids, especially cysteine, were lowered. S. molesta could be used as a Pb phytoremediator due to its high potential to survive Pb exposure and its ability to absorb Pb.
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