Total Input Research Articles

Distribusi Nitrogen pada Budidaya Ikan Koi (Cyprinus Rubrosfuscus) dalam Sistem Vertiqua Menggunakan Biofikal Filter Atas

Vertiqua is an innovation in vertical cultivation on limited land and water. Vertiqua continues to be developed to be effective in cultivating fish. This research aims to examine the effectiveness of nitrogen distribution in vertiqua using biofical top filters. The analysis used is quantitative analysis by calculating and testing the data that has been collected. Total nitrogen feed input, total nitrogen wasted, and percentage of nitrogen absorption were calculated using existing formulas. Comparative testing using the T – test on the Mini Tab application was carried out to test the effectiveness of nitrogen absorption. The research results showed that nitrogen absorption in the vertiqua using the top biofical filter was effective, ranging from 198,12 – 200,89 mg/l. Nitrogen absorption in the vertiqua without using a biofical top filter ranges from 42,75 – 43,35 mg/l. The distribution value of effective nitrogen absorption in vertiqua using the top biofical filter is shown by a P value <0,05. Vertiqua with a biofical top filter is also able to reduce nitrogen levels so that fish survival is good.

Unaccounted plastic: Estimating waste generation from marine vessels in Bangladesh

Solid waste mismanagement induces the release of a significant amount of plastic waste into the ocean, particularly in countries with poor solid waste management systems, such as Bangladesh. Nevertheless, the total plastic input of Bangladesh by multiple sources is still unknown. Waste input from land-based sources within 50 km coastline of this country is documented. However, the quantity of plastic entering the oceans from multiple sources, such as marine vessels, is still unknown and not documented. Passengers and goods are transported via marine vessels operating in Bangladesh's Inland Water Transport sector, which has the potential to generate a substantial quantity of plastic debris that remains unaccounted for. This study represented the initial attempt to quantify the amount of debris produced by passenger-carrying marine vessels in riverine systems. The estimated total amount of plastic waste generated per day per route from marine vessels stands at 76.6 kg. The total weight of plastic waste from all pathways was 436.3 kg, resulting in an estimated annual plastic waste generation of 157,068 kg. This yearly input is 0.6 % of Bangladesh's total mismanaged waste input into the Bay of Bengal, which is 0.79 million metric tonnes. The lack of implementation of regulatory measures and ineffective waste management systems can be pointed out as the main reason behind these plastic inputs. This paper identifies the current gaps in waste management practices for riverine plastic waste and is a forerunner to creating a baseline for unified policy formulation for the government.

Dual carbon isotopes (δ13C and Δ14C) were used to reveal the main sources and input fluxes of dissolved inorganic carbon in a karst reservoir in winter

In karst areas, the dissolved inorganic carbon (DIC) concentrations in aquatic systems are typically higher than that in non-karst areas due to intensive carbonate rock weathering. Understanding the sources and input fluxes of DIC in karst reservoirs is crucial for regional carbon cycle studies. This study utilized dual carbon isotopes (δ13CDIC and Δ14CDIC) to estimate the contribution rates and input fluxes of DIC from various sources in Aha Reservoir (AHR), located in southwestern China. Our results indicated that the DIC concentrations (22.33–32.79 mg L−1) and δ13CDIC values (−10.02‰ to −8.55‰) were nearly homogeneous both vertically and laterally in the reservoir (p > 0.05). The Δ14CDIC values (−246.31‰ to −137.86‰) were homogeneous along the vertical profile (p > 0.05), but showed significant horizontal variation (p < 0.05), with values decreasing from −149.57 ± 10.27‰ to −232.85 ± 2.37‰ at the mouths of the inflowing rivers. We found that the inflowing rivers were the primary DIC sources to AHR, contributing 70% of the total input, while groundwater and atmospheric CO2 contributions were relatively minor, at 18% and 12%, respectively. The Jinzhong River (JZR), influenced by industrial and domestic wastewater discharge, contributed the largest DIC input flux at 2.01 t/(km2·mon). In contrast, the Youyu River (YYR), influenced by acidic mine drainage, and the Baiyan River (BYR), influenced by agricultural activities, contributed relatively smaller DIC input fluxes of 1.29 t/(km2·mon) and 1.03 t/(km2·mon), respectively. This study highlights the significant impact of anthropogenic activities on DIC input in AHR, with industrial and domestic wastewater discharges having a greater influence than agricultural activities and acidic mine wastewater inputs. These findings underscore the critical need to manage and mitigate the impacts of human activities on karst reservoir ecosystems.

A novel cryogenic-thermochemical approach for clean hydrogen production from industrial flue gas streams with carbon capture and storage

The present work aims to develop a novel integrated energy system for clean hydrogen production from the industrial flue gas stream. The particular system incorporates a cryogenic distillation unit for H2S and CO2 separation and a thermochemical cycle for hydrogen production. The industrial flue gaseous mixture is considered a major feedstock for the present system. H2S is retrieved from the waste gaseous stream and fed to the two-step sulfur looping thermochemical cycle to perform clean hydrogen production. In this way, clean hydrogen production, elemental sulfur production, carbon capture, and storage are achieved. The entire integrated energy system is simulated in the Aspen Plus process simulator and is investigated thermodynamically in terms of energy and exergy performances. Various parametric studies are conducted to assess the significance of operating parameters on the system performance. The H2S and CO2 removal rates from the waste feed stream are found to be 85.55 % and 84.62 %. The H2S conversion into hydrogen is determined to be 66.67 %. The energy and exergy efficiencies of the two-step thermochemical cycle are found to be 53.93 % and 23.69 %, respectively. The parametric studies show that the hydrogen production rates of 3.63 kmol/h, 2.46 kmol/h, and 1.78 kmol/h are achieved at sulfurization temperatures of 200 °C, 300 °C, and 500 °C, respectively. The study further concludes that 44.60 % of the total input exergy is lost due to the presence of irreversibilities within the system. The overall energy and exergy efficiencies of the integrated energy system are found to be 82.99 % and 55.39 %, respectively.

Irrigation increases and stabilizes mosquito populations and increases West Nile virus incidence

Humans have greatly altered earth’s terrestrial water cycle with the majority of fresh water being used for agriculture. Irrigation changes spatial and temporal water availability and alters mosquito abundance and phenology. Previous studies evaluating the effect of irrigation on mosquito abundance and mosquito-borne disease have shown inconsistent results and little is known about the effect of irrigation on variability in mosquito abundance. We examined the effect of irrigation, climate and land cover on mosquito abundance and human West Nile virus (WNV) disease cases across California. Irrigation made up nearly a third of total water inputs, and exceeded precipitation in some regions. Abundance of two key vectors of several arboviruses, including WNV, Culex tarsalis and the Culex pipiens complex, increased 17–21-fold with irrigation. Irrigation reduced seasonal variability in C. tarsalis abundance by 36.1%. Human WNV incidence increased with irrigation, which explained more than a third (34.2%) of the variation in WNV incidence among California counties. These results suggest that irrigation can increase and decouple mosquito populations from natural precipitation variability, resulting in sustained and increased disease burdens. Shifts in precipitation due to climate change are likely to result in increased irrigation in many arid regions which could increase mosquito populations and disease.

A benthic source of isotopically heavy Ni from continental margins and implications for global ocean Ni isotope mass balance

Nickel (Ni) is a bio-essential element for phytoplankton in the modern oceans, and yet, the global ocean mass balance of Ni has puzzled scientists for decades. Many estimates of total Ni output flux are larger than the total Ni input flux to the ocean. The measurement of Ni stable isotopes (δ60Ni) in earth materials may inform our understanding of ocean biogeochemistry and redox conditions in both the modern ocean and the geological past. An ocean Ni stable isotope imbalance has also concerned scientists, with a global ocean δ60Ni of +1.4 ‰ which is notably heavier than the major source of Ni to the oceans from rivers. Recent efforts to resolve Ni and δ60Ni imbalances have focused on the role which manganese (Mn) oxides play in marine Ni cycling, both in the water column and in marine sediments. Manganese oxide rich marine sediments can supply isotopically heavy dissolved Ni to porewater fluids and seawater, but the source of the isotopically heavy porewater Ni remains unclear. Here we present porewater trace metal concentrations and δ60Ni from two sites from the continental margin off southern California. Porewater Ni concentrations are up to roughly 100-fold higher than deep seawater concentrations (∼1 μM compared to 10 nM, respectively). Porewater δ60Ni is near 0 ‰ in the subsurface region where Ni concentrations are highest, suggesting dissolution of lithogenic material from sediments. Porewater δ60Ni increases dramatically towards the sediment-water interface with values of up to +2.66 ‰, which to our knowledge are the heaviest Ni isotope compositions ever reported for natural materials. Measurements of porewater and sediment Ni and Mn concentrations suggest that Ni is released to porewaters in the Mn-reducing zone, and then removed by newly precipitated Mn oxides as Mn and Ni move towards the oxygenated zone of sediments. A simple Rayleigh model suggests a Ni isotope fractionation of factor of -0.61 ‰ for Ni sorption onto Mn oxides, while a diffusion-reaction model suggests a Ni isotope fractionation of -1.80 to -0.96 ‰, always with preferential adsorption of lighter Ni isotopes. This flux of Ni toward the sediment-water interface, coupled with preferential removal of lighter Ni isotopes in marine sediments, provides evidence supporting an isotopically heavy benthic source of new Ni to the oceans, which we estimate has a magnitude of 0.65 × 108 to 1.66 × 108 moles/year. We find that a benthic flux such as measured here over just 0.27-2.70 % of the ocean seafloor could mix with the river δ60Ni of +0.8 ‰ to achieve the observed deep ocean δ60Ni of +1.4 ‰. This study reveals the similarities in how rivers and continental margin sediments supply heavy Ni isotopes to the ocean. In both continental rivers and margin sediments, terrigenous Ni is released with an δ60Ni near 0.1 ‰, but lighter isotopes are captured by precipitation onto oxides so that the dissolved flux to the ocean is isotopically heavier than the terrigenous material from which Ni was released, and in the case of margin sediments may be heavier than even bulk seawater δ60Ni. We thus recognize continental margin sediments with active Mn cycling as a ‘new’ source of isotopically heavy dissolved Ni to the ocean.

Experimental study of DC excitation effect on the performance of moving coil linear compressor

In this paper, a novel Multi-loop Moving Coil Linear Compressor (M-MC-LC) is studied, in which the piston is driven by the Co-core Bilateral Reverse Coil (CBRC) in a reciprocating motion within the magnetic array. The DC excitation technique is introduced to address the phenomenon that the piston is axially offset under the influence of gas force. In order to clarify the effect of DC excitation on the performance of the moving-coil linear compressor, the compressor prototype is developed, and the dynamic performance testing test-bed and the refrigeration performance test-bed are built to qualitatively and quantitatively analyze the relevant performance parameters of the compressor from theoretical and experimental aspects. The results show that when the DC excitation accounts for less than 20% of the total input voltage, the pressure ratio increases with the increase of DC excitation; when the percentage is at 22.9%, a sudden drop in the volumetric efficiency of compressor occurs. Mass flow and COP increases first and then decreases with the increase of DC voltage excitation. The study results provide a guideline for the stable and reliable operation of the system and provide a valuable reference for the linear compressor piston offset adjustment.

A new seismic wave input method for canyon sites based on the finite element method-indirect boundary integral equation method

The seismic input is the basis for the seismic safety analysis of dams, but current seismic input methods have not reasonably considered the influence of canyon scattering effects on the dynamic response of dams. In this paper, the total motion field of the canyon is deconstructed into the free field of a uniform half space and the scattering field of the canyon and they are obtained separately. The indirect boundary integral equation method (IBIEM) is used to determine the scattering field of the canyon, which is superimposed with the free field to obtain the seismic ground motion field (total motion field) of the canyon. The accuracy of the total motion field of the canyon is verified through reference solutions. In the finite element analysis of seismic ground motion field in the canyon, the total motion field at the truncation boundary of the canyon foundation is transformed into the equivalent seismic input loads and the interior of the canyon are simulated using the finite element method (FEM). Then, based on the wave input for the free field combined with the viscoelastic artificial boundary, a new wave input method for the total motion field combined with the viscoelastic artificial boundary is established. The seismic wave input method based on the finite element-indirect boundary integral equation method is applied to numerically determine the seismic response of a trapezoidal canyon. The differences in the seismic response of the canyon under free-field input and total motion field input are discussed. The results show that there is a certain deviation between the displacement and waveform obtained from the free-field input and the solutions obtained from the indirect boundary integral equation method. There is a large error for a large angle of incidence, and the errors increase with increasing seismic wave frequency. When the incident angle is 60°, the maximum error in the frequency domain reaches 92.3 %, and the maximum error in the time domain reaches 250 %. The displacement amplitude and waveform of the canyon obtained from the total motion field input showed agreement with the results of the indirect boundary integral equation method. The wave input method established in this paper has high calculation accuracy and reasonably considers the scattering effect of canyons, which provides a basis for more accurate predictions of the seismic response of dams on canyon foundations.

The Carbon Footprint and Influencing Factors of the Main Grain Crops in the North China Plain

The North China Plain (NCP) serves as a critical grain-producing region in China, playing a pivotal role in ensuring the nation’s food security. A comprehensive analysis of the carbon footprint (CF) related to the cultivation of major grain crops within this region and the proposal of strategies to reduce emissions through low-carbon production methods are crucial for advancing sustainable agricultural practices in China. This study employed the lifecycle assessment (LCA) method to estimate the CF of wheat, maize, and rice crops over a period from 2013 to 2022, based on statistical data collected from five key provinces and cities in the NCP: Beijing, Tianjin, Hebei, Shandong, and Henan. Additionally, the Logarithmic Mean Divisia Index (LMDI) model was utilized to analyze the influencing factors. The results indicated that the carbon footprints per unit area (CFA) of maize, wheat, and rice increased between 2013 and 2022. Rice had the highest carbon footprint per unit yield (CFY), averaging 1.1 kg CO2-eq kg−1, with significant fluctuations over time. In contrast, the CFY of wheat and maize remained relatively stable from 2013 to 2022. Fertilizers contributed the most to CF composition, accounting for 48.8%, 48.0%, and 25.9% of the total carbon inputs for wheat, maize, and rice, respectively. The electricity used for irrigation in rice production was 31.8%, which was much higher than that of wheat (6.8%) and maize (7.1%). The LMDI model showed that the labor effect was a common suppressing factor for the carbon emissions of maize, wheat, and rice in the NCP, while the agricultural structure effect and the economic development effect were common driving factors. By improving the efficiency of fertilizer and pesticide utilization, cultivating new varieties, increasing the mechanical operation efficiency, the irrigation efficiency, and policy support, the CF of grain crop production in the NCP can be effectively reduced. These efforts will contribute to the sustainable development of agricultural practices in the NCP and support China’s efforts to achieve its “double carbon” target.

Mechanical behavior and energy characteristics of red sandstone with different seawater immersion heights under biaxial compression

Rock structures engineered during undersea mining are typically subjected to varying water distributions due to the motion of seawater, which considerably influences their stability. Hence, it is essential to understand the influence of seawater distribution on the mechanical behavior and energy characteristics of rocks. In this study, biaxial compression tests were conducted on red sandstone at various seawater immersion heights, and acoustic emission signals during compression were monitored. The results illustrate that the mechanical properties of the red sandstone deteriorate significantly upon seawater immersion. With an increase in seawater immersion height, the peak strength and elastic modulus of the rock specimens decreased exponentially. When the seawater immersion height was varied from 0 to 1/4 H under lateral stresses of 5, 10, 15, and 20 MPa, the peak strength decreased by 18.94%, 20.29%, 17.47%, and 14.87%, respectively, and the elastic modulus decreased by 4.6%, 8.1%, 11.7%, and 10.9%, respectively. Brittleness also decreased gradually. During compression, the acoustic emission (AE) and accumulated AE counts exhibited a stationary phenomenon, first increasing slowly and then suddenly. However, the AE counts decrease with increasing seawater immersion height. Meanwhile, with increasing seawater immersion height, the proportion of tensile cracks gradually increased and that of shear cracks gradually decreased. As the seawater immersion height increased, both the peak total input strain energy and peak total elastic strain energy decreased, whereas the peak total dissipated strain energy exhibited the opposite trend.

Laser powder bed fusion sintering mechanism of phenolic resin investigated by ReaxFF molecular dynamics simulations

ABSTRACT This study presents an innovative approach utilising molecular dynamics simulations to elucidate the polymerisation and neck formation mechanisms of phenolic resin during laser powder bed fusion (L-PBF). By developing system and dual-particle models and employing infrared thermal imaging, we established a heat source model for phenolic resin under varying parameters. Our molecular dynamics simulations, using the ReaxFF reactive force field, indicate that high-power lasers significantly enhance cross-linking, achieving a peak polymerisation degree of 78.9% at 30W and 35W power levels. Conversely, increased scanning speed slows product degradation, reducing the polymerisation degree. The interplay of laser power and scanning speed influences polymerisation, with total input energy and heating rate impacting polymerisation and molecular size. Additionally, we investigated neck formation, revealing that small vortices evolve into larger ones during sintering, promoting neck formation. Optical microscopy confirmed diverse neck shapes under different conditions. Quantitative data showed that at a scanning speed of 1000 mm/s, the polymerisation degree reached 93%, with only 2 molecules remaining post-simulation. At 30W power, the largest individual molecule observed was C849H703O117. This research offers crucial insights for selective laser sintering processes, emphasising the importance of high energy input and optimal heating rates for well-formed necks.

Species Richness Net Primary Productivity and the Water Balance Problem.

Species energy theory suggests that, because of limitations on reproduction efficiency, a minimum density of plant individuals per viable species exists and that this minimum correlates the total number of plant individuals N with the number of species S. The simplest assumption is that the mean energy input per individual plant is independent of the number of individuals, making N, and thus S as well, proportional to the total energy input into the system. The primary energy input to a plant-dominated ecosystem is estimated as its Net Primary Productivity (NPP). Thus, species energy theory draws a direct correspondence from NPP to S. Although investigations have verified a strong connection between S and NPP, strong influences of other factors, such as topography, ecological processes such as competition, and historical contingencies, are also at play. The lack of a simple model of NPP expressed in terms of the principal climate variables, precipitation P, and potential evapotranspiration, PET, introduces unnecessary uncertainty to the understanding of species richness across scales. Recent research combines percolation theory with the principle of ecological optimality to derive an expression for NPP(P, PET). Consistent with assuming S is proportional to NPP, we show here that the new expression for NPP(P, PET) predicts the number of plant species S in an ecosystem as a function of P and PET. As already demonstrated elsewhere, the results are consistent with some additional variation due to non-climatic inputs. We suggest that it may be easier to infer specific deviations from species energy predictions with increased accuracy and generality of the prediction of NPP(P, PET).

Free arc heating effect in double-layers hybrid arc source

Keyhole welding process is easily achieved with plasma arc heat source, but the welding speed for a stable keyhole is hard to increase because of the low-level heat input. Higher welding current will increase the heat input, but the induced heavy arc pressure acts to damage the keyhole stability. The narrow window of welding current creates limited usable range of heat input. Double-layers hybrid arc heat source is developed by compositing an outer layer of free arc into the center plasma arc jet. Set the plasma arc current level to create enough arc pressure to open a keyhole, the outer layer arc is used to control additional heat power into the weld pool but has little effect to influence the arc pressure. The free arc heating effect in the hybrid arc is figured out: (1) much faster welding speed can be achieved, it increases from 3 mm/s to 4.75 mm/s after additional 80 A/80 A free arcs are used, and (2) the increase of welding speed is highly related to the total heat input in the hybrid arc and is unrelated to the free arc number; (3) the calculated efficiency factor is selected as 0.75 for the added free arc. The developed hybrid arc is proved to be a robust method to increase the manufacturing efficiency.

Effect of High-Intensity Focused Ultrasound on Different Types of Adenomyosis Based on Magnetic Resonance Imaging Classification.

We aimed to analyze the effect of high-intensity focused ultrasound (HIFU) on different types of adenomyosis (AM) based on magnetic resonance imaging (MRI) classification. A total of 206 AM patients who underwent HIFU between January 2017 and December 2021 were included in this retrospective study. The size and location of AM were evaluated based on T2-weighted imaging (T2WI) of MRI. Patients were divided into internal (subtype I), external (subtype II), intramural (subtype III), and full-thickness (subtype IV) AM groups. All patients underwent an MRI examination before and one day after HIFU. After ultrasound-guided HIFU ablation, the parameters of ultrasonic energy input during HIFU treatment among different groups were recorded and compared. The adverse reactions and complications among different groups were compared. The lesion volume in the subtype IV group was significantly larger than the subtype II and III groups (P < .05). The HIFU irradiation time, treatment time, and total energy input in the subtype IV group were significantly higher than the subtype I and III groups (P < .05). The number of cases of abdominal pain and vaginal fluid in the treatment area in the subtype IV group was significantly higher than in the subtype II group. Although HIFU has different treatment strategies and parameters for different subtypes of AM, it can achieve a satisfactory ablation rate, which is safe and effective.

Innovative coupled cooling strategy for enhanced battery thermal management: Synergistic optimization of jet impingement and immersion cooling

This study introduces an innovative, synergistically optimized coupled cooling design that enhances lithium-ion battery thermal management for electric vehicles, merging jet impingement with immersion cooling techniques. Utilizing Computational Fluid Dynamics (CFD) numerical simulation, distributed iterative optimization is conducted. Initially, the inlet and outlet configurations are determined. Subsequently, the number of jet pipes and the flow distribution are optimized. Finally, the diameters of the jet pipes are refined. This process aims to enhance heat transfer efficiency and reduce total input cost. The results indicate that a design with three inlets and one outlet, using an inlet flow rate of 0.075 kg/s alongside the flow rate of 0.025 kg/s, achieves optimal thermal performance for the batteries. This configuration reduces the maximum battery temperature and average temperature by 17.61% and 15.05%, respectively. Furthermore, an excessive or insufficient number of jet pipes is detrimental to cooling within the battery. Relying solely on mainstream inlet or jet pipe coolant for refrigeration is far less effective than proportionally distributing flow between the two. Selecting 6 jet pipes and a distribution ratio of 2꞉1 can reduce the maximum temperature by 10.10%. In contrast to adjusting jet pipe diameters, optimizing flow distribution exerts a more significant influence on battery cooling efficiency. Ultimately, the optimized solution, compared to the original design (with a flow rate of 0.025 kg/s), reduces the maximum temperature and average temperature by 26.41% and 10.61%, respectively. These improvements demonstrate the effectiveness of coupling jet impingement and immersion methods in battery thermal management, offering valuable insights for the future development of EVs battery cooling technologies.

Aggravating Pollution of Emerging Aryl Organophosphate Esters in Urban Estuarine Sediments of South China.

Emerging aryl organophosphate esters (aryl-OPEs) have been employed as substitutes for organohalogen flame retardants in recent years; however, their environmental occurrence and associated impacts in urban estuarine sediments have not been adequately investigated, impeding regulatory decision-making. Herein, field-based investigations and modeling based on surface sediment and sediment core analysis were employed to uncover the historical pollution and current environmental impacts of aryl-OPEs in the Pearl River Estuary, South China. Our results revealed a substantial increase in aryl-OPE emission, particularly emerging aryl-OPEs, through sediment transport to the estuary since the 2000s. The emerging aryl-OPEs comprised 83% of the total annual input in the past decade, with an average annual input of 155,000 g. Additionally, the emerging-to-traditional aryl-OPE concentration ratios increased with decreasing distance from the shore, peaking in the highly urbanized riverine outlets. These findings indicate that inventories of emerging aryl-OPEs are likely increasing in estuarine sediments and their emissions are surpassing those of traditional aryl-OPEs. Our risk-based priority screening approach indicates that some emerging aryl-OPEs, particularly bisphenol A bis(diphenyl phosphate), can pose a higher environmental risk than traditional aryl-OPEs in estuarine sediments. Overall, our study highlights the importance of recognizing the environmental impacts of emerging aryl-OPEs.

Impact of crop rotation and tillage operations on mitigating greenhouse gas emissions and evaluation of sustainability index in rice- wheat-green gram cropping system of north Bihar

In North Bihar (NB), the conventional rice-wheat cropping system has led to soil, water, and environmental degradation, alongside low profitability, threatening sustainability. To address these concerns, a thorough field research was conducted over the course of three years to assess different methods of tillage and crop establishment in a rice, wheat, and greengram cycle. The experiment involved five scenarios with different combinations of crop rotation, tillage techniques, seeding procedures, fertilizer use, and irrigation strategies. Uncertainty analysis showed no significant change in mean and variance estimation among seven scenario replications at 5% significance level. Compared to traditional farming (SN-1), managing DSR-rice (SN-5) increased profitability by 17.56%, improved energy use efficiency (EUE) by 32.16%, and reduced irrigation by 24.76% and global warming potential (GWP) by 23.46%. Similarly, substituting zero tillage wheat (ZTW) SN-5 resulted in comparable profitability gains (18.25%) and significant improvements in irrigation (10 %), EUE (+48.65%), and GWP (−20 %) compared to SN-1. Green gram ZT also showed increased profitability (17.35%), with notable improvements in EUE (+38.31%) and GWP (−12.92%) compared to SN-1. Principal component and correlation analyses revealed relationships between total energy inputs, yields, economic returns, and sustainability indices, highlighting the benefits of crop rotation and tillage practices in optimizing resource use. The study suggests that compared to conventional systems, significant improvements in productivity, profitability, energy-use efficiency, and environmental mitigation can be achieved with Crop Rotation and Tillage Operations techniques.

Assessment of the migration characteristics and source-oriented health risks of heavy metals in the soil and groundwater of a legacy contaminated by the chlor-alkali industry in central China.

The chlor-alkali industry (CAI) is crucial for global chemical production; however, its operation has led to widespread heavy metal (HM) contamination at numerous sites, which has not been thoroughly investigated. This study analysed 122 soil and groundwater samples from a typical CAI site in Kaifeng, China. Our aim was to assess the ecological and health risks, identify the sources, and examine the migration characteristics of HMs at this site using Monte Carlo simulation, absolute principal component score-multiple linear regression (APCS-MLR), and the potential environmental risk index (Ei). Our findings revealed that the exceedance rates for Cd, Pb, Hg, and Ni were 71.96%, 45.79%, 49.59%, and 65.42%, respectively. Mercury (Hg) displayed the greatest coefficient of variation across all the soil layers, indicating a significant anthropogenic influence. Cd and Hg were identified as having high and extremely high potential environmental risk levels, respectively. The spatial distributions of the improved Nemerow index (INI), total ecological risk (Ri), and HM content varied considerably, with the most contaminated areas typically associated with the storage of raw and auxiliary materials. Surface aggregation and significant vertical transport were noted for HMs; As and Ni showed substantial accumulation in subsoil layers, severely contaminating the groundwater. Self-organizing maps categorized the samples into two different groups, showing strong positive correlations between Cd, Pb, and Hg. The APCS-MLR model suggested that industrial emissions were the main contributors, accounting for 60.3% of the total HM input. Elevated hazard quotient values for Hg posed significant noncarcinogenic risks, whereas acceptable levels of carcinogenic risk were observed for both adults (96.60%) and children (97.83%). This study significantly enhances historical CAI pollution data and offers valuable insights into ongoing environmental and health challenges.

Assessment of soil-groundwater nitrogen cycling processes in the agricultural region through flux model, stable isotope

The nitrogen cycle in the soil-groundwater system of agricultural land is a crucial process within the global nitrogen cycle. Human activities have significantly intensified this cycling process in agricultural fields, consequently leading to substantial accumulation of nitrogen in the soil-groundwater system and giving rise to numerous ecological health issues. Quantitative assessment of soil-groundwater nitrogen cycling processes can facilitate the optimization of nitrogen management strategies in agricultural fields and the prevention and management of groundwater nitrogen pollution. However, accurately quantifying the intricate soil-groundwater nitrogen cycling dynamics in agro-irrigation areas characterized by diverse nitrogen sources and complex hydrogeological conditions poses a significant challenge. The Songhua River Basin in the Sanjiang Plain was selected as the study area for this investigation. We utilized the INCA-N model to simulate annual nitrogen fluxes in the soil-groundwater system of an agricultural watershed, and employed stable isotope and water chemistry methods to identify sources of groundwater nitrogen contamination and transformation processes. Ultimately, we conducted a comprehensive assessment of nitrogen cycling within the soil-groundwater system of the agricultural watershed. The findings revealed that atmospheric deposition, nitrogen fixation, and fertilization constituted the primary mechanisms of soil nitrogen input. Plant uptake, riverine nitrogen transport, and denitrification were identified as the three principal processes responsible for soil-groundwater nitrogen export. The results obtained from the MIXSIAR model demonstrate a substantial contribution of nitrogen fertiliser and soil nitrogen to groundwater nitrate, followed by faeces and sewage. Additionally, the annual input fluxes of nitrogen simulated by INCA-N reveal that fertiliser application is the primary contributor, which aligns to some extent with the findings of the MIXSIAR model. Soil nitrogen can serve as a relatively stable source of groundwater nitrate, while anthropogenic activities such as fertilizer application, manure deposition, and sewage discharge are likely to be the primary drivers of groundwater nitrate pollution. By quantifying the N input and output fluxes, it was determined that approximately 58% of the total annual nitrogen input has the potential to accumulate within the soil-groundwater system. The effective utilization of legacy nitrogen can contribute to the reduction of soil-groundwater nitrogen fluxes, while maintaining crop yields and mitigating greenhouse gas emissions. This study aims to optimize nitrogen management practices in agricultural areas and provide valuable insights for water conservation strategies.

Alternate wetting and drying: a water-saving technology for sustainable rice production in Burkina Faso?

With emerging water scarcity and rising fertilizer prices, optimising future water use while maintaining yield and nutrient efficiency in irrigated rice is crucial. Alternate wetting and moderate soil drying irrigation (i.e., re-irrigation when the water level reaches 15 cm below the soil surface) has proven to be an efficient water-saving technology in semi-arid zones of West Africa, reducing water inputs without yield penalty. Alternate wetting and severe soil drying (AWD30), by re-irrigating fields only when the water table reaches 30 cm below the soil surface, may further reduce water inputs compared to farmers’ irrigation practices (FP). However, acute soil drying may impair fertilizer use efficiency and reduce the bio-availability of some key nutrients. This study assessed the potentials and risks associated with AWD30 for smallholder rice farmers in the semi-arid zones of West Africa. We conducted 30 on-farm field trials over three seasons (wet and dry seasons of 2019, and dry season of 2020), in Kou Valley, Burkina Faso. We assessed yield, water productivity, nutrient uptake, and use efficiency under AWD30 and FP. In FP, farmers maintained their fields submerged as frequently as possible according to the scheme-dependent water provision schedule. With AWD30, irrigation frequency was reduced by 30%, however, soils were seldom completely dried due to a shallow groundwater table. Compared to FP, AWD30 reduced irrigation water input by 37% with no significant effects on grain yields (average of 4.5 Mg ha−1), thus increasing average water productivity by 39%. Both irrigation management practices provided comparable crop uptake of N, P, and K, and use efficiencies of applied N and P. However, the N content in straw and the P concentration in grain generally increased with total water input (rain + irrigation). We conclude that at locations with a shallow groundwater table, AWD30 can effectively save irrigation water without significantly reducing the grain yield and the use efficiency of applied mineral nutrients.