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1.
Environ Pollut ; 356: 124250, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38810685

RESUMO

Biochar was generally used to reduce the macronutrient releases and to mitigate N2O gas emissions in cropland. This experiment evaluated the trend of major plant nutrient releases using the modified Hyperbola model and the greenhouse gas emissions by incorporating different poultry manure compost biochar with organic resources. The treatments consisted of the control as the organic fertilizer materials, the incorporated poultry manure compost biochar with organic fertilizer materials (PMCBF), and the incorporated plasma-activated poultry manure compost biochar with organic fertilizer materials (PAMBF) under redox conditions. The results showed that the cumulated highest concentrations of NH4-N and NO3-N were 2168.6 mg L-1 and 21.7 mg L-1 in the control, respectively. Compared with the control, the predicted reduction rates of NH4-N release from the PMCBF and PAMBF were 26.2% and 15.4%, respectively. In the control, the cumulated highest concentrations of PO4-P and K in leachate were 681.04 mg L-1 and 120.5 mg L-1, respectively. The predicted reduction rates of PO4-P and K were 55.1% and 15.5%, respectively, under the PAMBF compared to the control. The modified Hyperbola model with cumulated NH4-N, PO4-P, and K-releases under the treatments was a good fit (p < 0.0001). For greenhouse gas (GHG) emissions, the lowest cumulative N2O was 59.59 mg m-2 in the soil incorporated with PMCBF, and its reduction rate was 23.5% compared with the control. The findings of this study will contribute to more profound insights into the potential application of PAMBF and PMCBF as bio-fertilizers adapted to mitigate NH4-N, PO4-P, and K releases and N2O emissions, offering scientific evidence for organic farming strategies.

2.
J Hazard Mater ; 471: 134346, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38653139

RESUMO

Soil, particularly in agricultural regions, has been recognized as one of the significant reservoirs for the emerging contaminant of MPs. Therefore, developing a rapid and efficient method is critical for their identification in soil. Here, we coupled HSI systems [i.e., VNIR (400-1000 nm), InGaAs (800-1600 nm), and MCT (1000-2500 nm)] with machine learning algorithms to distinguish soils spiked with white PE and PA (average size of 50 and 300 µm, respectively). The soil-normalized SWIR spectra unveiled significant spectral differences not only between control soil and pure MPs (i.e., PE 100% and PA 100%) but also among five soil-MPs mixtures (i.e., PE 1.6%, PE 6.9%, PA 5.0%, and PA 11.3%). This was primarily attributable to the 1st-3rd overtones and combination bands of C-H groups in MPs. Feature reductions visually demonstrated the separability of seven sample types by SWIR and the inseparability of five soil-MPs mixtures by VNIR. The detection models achieved higher accuracies using InGaAs (92-100%) and MCT (97-100%) compared to VNIR (44-87%), classifying 7 sample types. Our study indicated the feasibility of InGaAs and MCT HSI systems in detecting PE (as low as 1.6%) and PA (as low as 5.0%) in soil. SYNOPSIS: One of two SWIR HSI systems (i.e., InGaAs and MCT) with a sample imaging surface area of 3.6 mm² per grid cell was sufficient for detecting PE (as low as 1.6%) and PA (as low as 5.0%) in soils without the digestion and separation procedures.

3.
Polymers (Basel) ; 15(21)2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37959965

RESUMO

The presence of heavy metals with high acute toxicity in wastewater poses a substantial risk to both the environment and human health. To address this issue, we developed a nanocomposite of alginate-encapsulated polypyrrole (PPy) decorated with α-Fe2O3 nanoparticles (Alg@Mag/PPy NCs), fabricated for the removal of mercury(II) from synthetic wastewater. In the adsorption experiments, various parameters were examined to identify the ideal conditions. These parameters included temperature (ranging from 298 to 323 K), initial pH levels (ranging from two to nine), interaction time, amount of adsorbent (from 8 to 80 mg/40 mL), and initial concentrations (from 10 to 200 mg/L). The results of these studies demonstrated that the removal efficiency of mercury(II) was obtained to be 95.58% at the optimum pH of 7 and a temperature of 303 K. The analysis of adsorption kinetics demonstrated that the removal of mercury(II) adhered closely to the pseudo-second-order model. Additionally, it displayed a three-stage intraparticle diffusion model throughout the entire adsorption process. The Langmuir model most accurately represented equilibrium data. The Alg@Mag/PPy NCs exhibited an estimated maximum adsorption capacity of 213.72 mg/g at 303 K, surpassing the capacities of most of the other polymer-based adsorbents previously reported. The thermodynamic analysis indicates that the removal of mercury(II) from the Alg@Mag/PPy NCs was endothermic and spontaneous in nature. In summary, this study suggests that Alg@Mag/PPy NCs could serve as a promising choice for confiscating toxic heavy metal ions from wastewater through adsorption.

4.
Adv Colloid Interface Sci ; 318: 102955, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37467558

RESUMO

The modern eco-friendly materials used in research and innovation today consist of nanocomposites and bio-nanocomposite polymers. Their unique composite properties make them suitable for various industrial, medicinal, and energy applications. Bio-nanocomposite polymers are made of biopolymer matrices that have nanofillers dispersed throughout them. There are several types of fillers that can be added to polymers to enhance their quality, such as cellulose-based fillers, clay nanomaterials, carbon black, talc, carbon quantum dots, and many others. Biopolymer-based nanocomposites are considered a superior alternative to traditional materials as they reduce reliance on fossil fuels and promote the use of renewable resources. This review covers the current state-of-the-art in nanocomposite and bio-nanocomposite materials, focusing on ways to improve their features and the various applications they can be used for. The review article also investigates the utilization of diverse nanocomposites as a viable approach for developing bio-nanocomposites. It delves into the underlying principles that govern the synthesis of these materials and explores their prospective applications in the biomedical field, food packaging, sensing (Immunosensors), and energy storage devices. Lastly, the review discusses the future outlook and current challenges of these materials, with a focus on sustainability.

5.
Sensors (Basel) ; 23(9)2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37177505

RESUMO

By virtue of their wide applications in transportation, healthcare, smart home, and security, development of sensors detecting mechanical stimuli, which are many force types (pressure, shear, bending, tensile, and flexure) is an attractive research direction for promoting the advancement of science and technology. Sensing capabilities of various force types based on structural design, which combine unique structure and materials, have emerged as a highly promising field due to their various industrial applications in wearable devices, artificial skin, and Internet of Things (IoT). In this review, we focus on various sensors detecting one or two mechanical stimuli and their structure, materials, and applications. In addition, for multiforce sensing, sensing mechanism are discussed regarding responses in external stimuli such as piezoresistive, piezoelectric, and capacitance phenomena. Lastly, the prospects and challenges of sensors for multiforce sensing are discussed and summarized, along with research that has emerged.

6.
Pestic Biochem Physiol ; 190: 105332, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36740336

RESUMO

The current study investigated the multifunctional properties of Cadmium Sulphide Nanoparticles synthesized using a green synthesis method (CdS NPs) using a green feedstock, Nopal Cactus fruit extract. The biological activities of the CdS NPs were thoroughly investigated, including their insecticidal, antibacterial, and anticancer activities. The different concentrations (0.005-0.04%) of CdS NPs were fed to the larvae of Spodoptera litura, and their ingestion effects were observed on the different biological, biochemical, and oxidative stress markers. There are significant dose-dependent changes in the biochemical parameters like superoxide dismutase (SOD), Catalase (CAT), Glutathione-S-transferase (GST), and MDA level as a marker of lipid peroxidation in the treated larvae were studied. In the highest concentration (0.04%), significant larval mortality (46.66%), malformation (pupae and adult) (27.78%), inhibition of adult emergence (43.87%), as well as reduced fecundity (25.28%), and fertility (22.74%) as compared to control was observed. CdS NPs have been investigated for antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus bacterial strains. In vitro anticancer activities were carried out to decrease the viability of the Pancreatic cancer cell line. The cells showed 18% and 12% viability at a 200 µg/ml concentration when incubated with CdS NPs for 24 and 48 h, respectively, confirming its potent anticancer property. The lack of cytotoxicity against the (RBC) endorses the biocompatible nature of synthesized CdS NPs. It was observed that green synthesized CdS NPs could be used as a promising insecticidal, antibacterial, and anticancer agent.


Assuntos
Inseticidas , Nanopartículas , Animais , Spodoptera , Inseticidas/farmacologia , Inseticidas/química , Antibacterianos/farmacologia , Larva , Ingestão de Alimentos , Extratos Vegetais/farmacologia
7.
Artigo em Inglês | MEDLINE | ID: mdl-36231705

RESUMO

For this experiment, pelletized activated biochar made of rice hullsor palm bark with swine manure compost was prepared to demonstrate the significant benefits of applying activated biochar-manure compost pellet fertilizer (ABMCP) inmitigating volatile organic compounds (VOCs), odor emission, and heavy metal saturation. Morphology and surface area analysis indicated that the activated rice hull biochar-manure compost pellet (ARP) had a significantly lower surface area, porous volume, and Fe content the activated palm biochar-manure compost pellet (APP). However, the ARP presented great potential to mitigate VOCs and odorant emissions. Our results indicated that the ARP reduced total reduced sulfur (TRS) and volatile fatty acids (VFAs) emissions by 69% and 93%, respectively. Heavy metals such as Pb, As, and Cd were not detected in the leachates fromthe ARP, APP, and swine manure compost. These results suggest that ABMCP can be a potential adsorbent to control VOCs and odorant emissions andpromote sustainable swine manure management and agricultural application.


Assuntos
Compostagem , Metais Pesados , Compostos Orgânicos Voláteis , Animais , Cádmio , Carvão Vegetal , Fertilizantes , Chumbo , Esterco , Metais Pesados/análise , Solo , Enxofre , Suínos
8.
Sensors (Basel) ; 22(12)2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35746242

RESUMO

Many modern user interfaces are based on touch, and such sensors are widely used in displays, Internet of Things (IoT) projects, and robotics. From lamps to touchscreens of smartphones, these user interfaces can be found in an array of applications. However, traditional touch sensors are bulky, complicated, inflexible, and difficult-to-wear devices made of stiff materials. The touch screen is gaining further importance with the trend of current IoT technology flexibly and comfortably used on the skin or clothing to affect different aspects of human life. This review presents an updated overview of the recent advances in this area. Exciting advances in various aspects of touch sensing are discussed, with particular focus on materials, manufacturing, enhancements, and applications of flexible wearable sensors. This review further elaborates on the theoretical principles of various types of touch sensors, including resistive, piezoelectric, and capacitive sensors. The traditional and novel hybrid materials and manufacturing technologies of flexible sensors are considered. This review highlights the multidisciplinary applications of flexible touch sensors, such as e-textiles, e-skins, e-control, and e-healthcare. Finally, the obstacles and prospects for future research that are critical to the broader development and adoption of the technology are surveyed.


Assuntos
Robótica , Dispositivos Eletrônicos Vestíveis , Humanos
9.
Sci Adv ; 8(12): eabj9220, 2022 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-35333568

RESUMO

Accurate transmission of biosignals without interference of surrounding noises is a key factor for the realization of human-machine interfaces (HMIs). We propose frequency-selective acoustic and haptic sensors for dual-mode HMIs based on triboelectric sensors with hierarchical macrodome/micropore/nanoparticle structure of ferroelectric composites. Our sensor shows a high sensitivity and linearity under a wide range of dynamic pressures and resonance frequency, which enables high acoustic frequency selectivity in a wide frequency range (145 to 9000 Hz), thus rendering noise-independent voice recognition possible. Our frequency-selective multichannel acoustic sensor array combined with an artificial neural network demonstrates over 95% accurate voice recognition for different frequency noises ranging from 100 to 8000 Hz. We demonstrate that our dual-mode sensor with linear response and frequency selectivity over a wide range of dynamic pressures facilitates the differentiation of surface texture and control of an avatar robot using both acoustic and mechanical inputs without interference from surrounding noise.

10.
Sensors (Basel) ; 22(3)2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35161632

RESUMO

Recently, temperature monitoring with practical colorimetric sensors has been highlighted because they can directly visualize the temperature of surfaces without any power sources or electrical transducing systems. Accordingly, several colorimetric sensors that convert the temperature change into visible color alteration through various physical and chemical mechanisms have been proposed. However, the colorimetric temperature sensors that can be used at subzero temperatures and detect a wide range of temperatures have not been sufficiently explored. Here, we present a colorimetric sensory system that can detect and visualize a wide range of temperatures, even at a temperature below 0 °C. This system was developed with easily affordable materials via a simple fabrication method. The sensory system is mainly fabricated using hydroxypropyl cellulose (HPC) and ethylene glycol as the coolant. In this system, HPC can self-assemble into a temperature-responsive cholesteric liquid crystalline mesophase, and ethylene glycol can prevent the mesophase from freezing at low temperatures. The colorimetric sensory system can quantitatively visualize the temperature and show repeatability in the temperature change from -20 to 25 °C. This simple and reliable sensory system has great potential as a temperature-monitoring system for structures exposed to real environments.


Assuntos
Colorimetria , Cristais Líquidos , Celulose/análogos & derivados , Temperatura
11.
Int J Mol Sci ; 23(2)2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-35054803

RESUMO

Self-healing materials have been attracting the attention of the scientists over the past few decades because of their effectiveness in detecting damage and their autonomic healing response. Self-healing materials are an evolving and intriguing field of study that could lead to a substantial increase in the lifespan of materials, improve the reliability of materials, increase product safety, and lower product replacement costs. Within the past few years, various autonomic and non-autonomic self-healing systems have been developed using various approaches for a variety of applications. The inclusion of appropriate functionalities into these materials by various chemistries has enhanced their repair mechanisms activated by crack formation. This review article summarizes various self-healing techniques that are currently being explored and the associated chemistries that are involved in the preparation of self-healing composite materials. This paper further surveys the electronic applications of self-healing materials in the fields of energy harvesting devices, energy storage devices, and sensors. We expect this article to provide the reader with a far deeper understanding of self-healing materials and their healing mechanisms in various electronics applications.


Assuntos
Eletrônica , Polímeros/química , Reação de Cicloadição , Elastômeros/química , Ligação de Hidrogênio
12.
Environ Pollut ; 285: 117457, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34380210

RESUMO

Supplemental activated biochar pellet fertilizers (ABPFs) were evaluated as a method to sequester carbon and reduce greenhouse gas (GHG) emissions, and improve rice production. The evaluated treatments were a control (standard cultivation method, no additives applied), activated rice hull biochar pellets with 40% of N (ARHBP-40%), and activated palm biochar pellets with 40% of N (APBP-40%). The N supplied by the ARHBP-40% and APBP-40% treatments reduced the need for supplemental inorganic nitrogen (N) fertilizer by 60 percent. The ARHBP-40% treatment sequestered as much as 1.23 tonne ha-1 compared to 0.89 tonne ha-1 in the control during the rice-growing season. In terms of greenhouse gas (GHG) emissions, CH4 emissions were not significantly different (p > 0.05) between the control and the ARHBP-40%, while the lowest N2O emissions (0.002 kg ha-1) were observed in the ARHBP-40% during the crop season. Additionally, GHG (CO2-equiv.) emissions from the ARHBP-40% application were reduced by 10 kg ha-1 compared to the control. Plant height in the control was relatively high compared to others, but grain yield was not significantly different among the treatments. The application of the ARHBP-40% can mitigate greenhouse gas emissions and enhance carbon sequestration in crop fields, and ABPFs can increase N use efficiency and contribute to sustainable agriculture.


Assuntos
Gases de Efeito Estufa , Oryza , Agricultura , Sequestro de Carbono , Carvão Vegetal , Fertilizantes/análise , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise , Solo
13.
Sensors (Basel) ; 21(14)2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34300493

RESUMO

Highly sensitive and flexible composite sensors with pressure and temperature sensing abilities are of great importance in human motion monitoring, robotic skins, and automobile seats when checking the boarding status. Several studies have been conducted to improve the temperature-pressure sensitivity; however, they require a complex fabrication process for micro-nanostructures, which are material-dependent. Therefore, there is a need to develop the structural designs to improve the sensing abilities. Herein, we demonstrate a flexible composite with an enhanced pressure and temperature sensing performance. Its structural design consists of a multilayered composite construction with an elastic modulus gradient. Controlled stress concentration and distribution induced by a micropatterned structure between the layers improves its pressure and temperature sensing performance. The proposed composite sensor can monitor a wide range of pressure and temperature stimuli and also has potential applications as an automotive seat sensor for simultaneous human temperature detection and occupant weight sensing.


Assuntos
Nanoestruturas , Dispositivos Eletrônicos Vestíveis , Humanos , Monitorização Fisiológica , Temperatura , Sensação Térmica
14.
Chemosphere ; 270: 128625, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33077185

RESUMO

Biochar as a soil amendment has been proposed for enhancing carbon sequestration and manure-borne hormone contaminant remediation. However, little is known about the ecological risk of biochar application in the soil with hormone contamination. This study investigated the influence of biochar in three manure-impacted soils contaminated with estrogen hormones, natural estrogen 17ß-estradiol and synthesized estrogen 17α-ethinylestradiol in a microcosm experiment. Specifically, microbial respiration was periodically determined during microcosm incubation while microbial community phospholipid fatty acids and activities of nutrient (C, N, P, S) cycling related enzymes (ß-glucosidase, urease, phosphodiesterase, arylsulfatase) were characterized after the incubation. Results showed that the manure-impacted soils with high SOC generally had greater total microbial biomass, ratios of fungi/bacteria and Gram-positive bacteria/Gram-negative bacteria, and phosphodiesterase activity, but lower urease activity. Additionally, hormones stimulated microbial respiration and biomass, while had little impact on activity of the enzymes. On the other hand, biochar showed negative priming effect by significantly decreasing total microbial biomass by 8.7%-26.4%, CO2 production by 16.6%-33.5%, and glucosidase activity by 27.1%-41.0% in the three soils. Biochar significantly increased the activity of phosphodiesterase, showed no impact on arylsulfatase, while decreased the activity of urease. Overall, the study suggests that when used in hormone remediation in manure-impact soils, biochar could improve phosphodiesterase activity, but may decrease soil microbial activity and the activity of soil glucosidase and urease.


Assuntos
Microbiota , Solo , Carvão Vegetal , Estrogênios , Esterco , Respiração , Microbiologia do Solo
15.
ACS Appl Mater Interfaces ; 12(16): 18813-18822, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32233452

RESUMO

The development of a flexible electronic skin (e-skin) highly sensitive to multimodal vibrations and a specialized sensing ability is of great interest for a plethora of applications, such as tactile sensors for robots, seismology, healthcare, and wearable electronics. Here, we present an e-skin design characterized by a bioinspired, microhexagonal structure coated with single-walled carbon nanotubes (SWCNTs) using an ultrasonic spray method. We have demonstrated the outstanding performances of the device in terms of the capability to detect both static and dynamic mechanical stimuli including pressure, shear displacement, and bending using the principles of piezoresistivity. Because of the hexagonal microcolumnar array, whose contact area changes according to the mechanical stimuli applied, the interlock-optimized geometry shows an enhanced sensitivity. This produces an improved ability to discriminate the different mechanical stimuli that might be applied. Moreover, we show that our e-skins can detect, discriminate, and monitor various intensities of different external and internal vibrations, which is a useful asset for various applications, such as seismology, smart phones, wearable human skins (voice monitoring), etc.


Assuntos
Nanotubos de Carbono/química , Ultrassom/métodos , Dispositivos Eletrônicos Vestíveis , Eletrônica , Desenho de Equipamento , Humanos , Fenômenos Mecânicos , Smartphone , Voz/fisiologia
16.
ACS Omega ; 5(6): 2630-2639, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32095686

RESUMO

In this study, we investigated the gauge factor and compressive modulus of hybrid nanocomposites of exfoliated graphite nanoplatelets (xGnP) and multiwalled carbon nanotubes (MWCNTs) in a polydimethylsiloxane matrix under compressive strain. Mechanical and electrical tests were conducted to investigate the effects of nanofiller wt %, the xGnP size, and xGnP:MWCNT ratio on the compressive modulus and sensitivity of the sensors. It was found that nanofiller wt %, the xGnP size, and xGnP:MWCNT ratio significantly affect the electromechanical properties of the sensor. The compressive modulus increased with an increase in the nanofiller wt % and a decrease in the xGnP size and xGnP:MWCNT ratio. However, the gauge factor decreases with a decrease in the nanofiller wt % and xGnP size and an increase in the xGnP:MWCNT ratio. Therefore, by investigating the piezoresistive effects of various factors for sensing performance, such as wt %, xGnP size, and xGnP:MWCNT ratio, the concept of one- and two-dimensional hybrid fillers provides an effective way to tune both mechanical properties and sensitivity of nanocomposites by tailoring the network structure of fillers.

17.
Sci Total Environ ; 686: 959-967, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31200312

RESUMO

Animal manure application in agricultural land has caused the release of steroid estrogens in the soil environment and further movement to aquatic systems. The objective of this study was to investigate the effects of biochar addition on sorption-desorption and dissipation behaviors of 17α­ethinylestradiol (EE2) in two different textured soils. A Commerce sandy loam and a Shakey clay were selected and subjected to sterilization. Soil samples with and without sterilization were reacted with a series of EE2 solutions of different concentrations for sorption followed by desorption and quantification using HPLC-MS/MS. Long-term dissipation of EE2 in the same soils was also evaluated over a 30-d incubation. Biochar amendment increased the maximum EE2 sorption capacity but decreased its water desorption in both sandy loam and clay soils. On other hand, biochar addition increased the Koc in the clay soil which had low EE2 sorption efficiency but decreased Koc in the sandy loam which had high EE2 sorption efficiency. Biochar did significantly increase both desorbable and non-extractable fractions of EE2, while it reduced the bioavailability of EE2 to microbial degradation. The dissipation of EE2 in non-sterilized soils fit to the first-order kinetic model, whereas it was better described by zero-order kinetic for sterilized soil. Biochar increased the half-life of EE2 dissipation in non-sterilized Commerce sandy loam soil by 48% (from 3.63 to 5.37 d) and in non-sterilized Sharkey clay soil by 67% (from 2.28 to 3.81 d). Overall, this study demonstrated positive impacts of biochar on the retention of estrogen hormones in soils.


Assuntos
Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Etinilestradiol/química , Poluentes do Solo/química , Argila/química , Solo/química , Poluentes do Solo/análise
18.
Sci Total Environ ; 624: 744-752, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29272843

RESUMO

The use of hairy vetch as a winter cover crop for cotton production in Northwest Louisiana has contributed to sustaining cotton production as well as improving soil quality. To test the efficacy of hairy vetch (HV) cultivation as a natural N supplement for cotton production, a long-term field experiment lasting 27years was evaluated using the Denitrification-Decomposition (DNDC) model. Different N fertilization practices, including 0kgNha-1 (PL_1), HV alone (PL_2), 44.8kgNha-1 (PL_3), and 67.3kgNha-1 (PL_4), were compared to evaluate nitrogen (N) response to cotton yield. Measured crop yield from each treatment was used to calibrate and validate the model. The DNDC model was employed to test the effects of N application scenarios on cotton yields and HV incorporation on N balance under irrigated and non-irrigated conditions. In model calibration, statistical indices for the model performance on cotton seed yield showed that PL_1 had a normalized root mean square error (NRMSE) value of 24.5%, a model efficiency (ME) value of 0.51, and a correlation coefficient (r) of 0.87 (P<0.01). The DNDC model was validated with PL_2, PL_3, and PL_4. PL_2, PL_3 and PL_4 had a NRMSE of 18.6%, 16.4% and 15.8% respectively, ME value of 0.19, 0.47 and 0.52 respectively, and an r of 0.75, 0.83 and 0.85 (P<0.05) respectively. Estimates of soil organic carbon (SOC) for HV treatment showed double the SOC content during a 27-year long-term experiment, while both treatments of 44.8kgNha-1 and 67.3kgNha-1 showed similar levels of SOC of a 25% increase compared to the control. Based on the scenario analysis, sustainable cotton yields do not require N fertilizer application under HV cultivated fields, and no yield differences were observed between irrigated and non-irrigated conditions.


Assuntos
Agricultura , Gossypium/crescimento & desenvolvimento , Solo/química , Vicia/crescimento & desenvolvimento , Carbono , Produtos Agrícolas/crescimento & desenvolvimento , Desnitrificação , Fertilizantes , Louisiana , Modelos Teóricos , Nitrogênio
19.
Environ Monit Assess ; 189(11): 547, 2017 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-28994015

RESUMO

Drought is a critical issue, and it has a pressing, negative impact on agriculture, ecosystems, livelihoods, food security, and sustainability. The problem has been studied globally, but its regional or even local dimension is sometimes overlooked. Local-level drought assessment is necessary for developing adaptation and mitigation strategies for that particular region. Keeping this in understanding, an attempt was made to create a detailed assessment of drought characteristics at the local scale in Bangladesh. Standardized precipitation evapotranspiration (SPEI) is a new drought index that mainly considers the rainfall and evapotranspiration data set. Globally, SPEI has become a useful drought index, but its local scale application is not common. SPEIbase (0.5° grid data) for 110 years (1901-2011) was utilized to overcome the lack of long-term climate data in Bangladesh. Available weather data (1955-2011) from Bangladesh Meteorology Department (BMD) were analyzed to calculate SPEIweather station using the SPEI calculator. The drivers for climate change-induced droughts were characterized by residual temperature and residual rainfall data from different BMD stations. Grid data (SPEIbase) of 26 stations of BMD were used for drought mapping. The findings revealed that the frequency and intensity of drought are higher in the northwestern part of the country which makes it vulnerable to both extreme and severe droughts. Based on the results, the SPEI-based drought intensity and frequency analyses were carried out, emphasizing Rangpur (northwest region) as a hot spot, to get an insight of drought assessment in Bangladesh. The findings of this study revealed that SPEI could be a valuable tool to understand the evolution and evaluation of the drought induced by climate change in the country. The study also justified the immediate need for drought risk reduction strategies that should lead to relevant policy formulations and agricultural innovations for developing drought adaptation, mitigation, and resilience mechanisms in Bangladesh.


Assuntos
Secas , Monitoramento Ambiental , Agricultura , Bangladesh , Mudança Climática , Ecossistema , Meteorologia , Chuva , Padrões de Referência , Temperatura
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