Ecosystems along the eastern margin of the Qinghai-Tibet Plateau(EQTP)are highly fragile and extremely sensitive to climate change and human disturbances.To quantitatively assess climate-induced ecosystem responses,th...Ecosystems along the eastern margin of the Qinghai-Tibet Plateau(EQTP)are highly fragile and extremely sensitive to climate change and human disturbances.To quantitatively assess climate-induced ecosystem responses,this study proposes a Climate-Induced Productivity Index(CIPI)based on the Super Slack-Based Measure(Super-SBM)model using remote sensing data from 2001 to 2020.The results reveal persistently low CIPI values(0.47-0.53)across major ecosystem types,indicating widespread vulnerability to climatic variability.Among these ecosystems,forests exhibit the highest CIPI(0.55),followed by shrublands(0.54),croplands(0.53),grasslands(0.51),and barelands(0.43).The Theil index analysis further demonstrates significant intra-group disparities,suggesting that extreme climatic events amplify CIPI heterogeneity.Moreover,the dominant environmental drivers differ among ecosystem types:the Palmer Drought Severity Index(PDSI)primarily constrains grassland productivity,solar radiation(SRAD)strongly influences shrub and cropland systems,whereas subsurface factors exert greater control in forested regions.This study provides a quantitative framework for evaluating climate-ecosystem interactions and offers a scientific basis for long-term ecological monitoring and security planning across the EQTP.展开更多
Vegetation in terrestrial ecosystems as a carbon sink is a crucial factor in mitigating global warming and reaching carbon neutrality targets,although the drivers of net ecosystem productivity(NEP)under combined human...Vegetation in terrestrial ecosystems as a carbon sink is a crucial factor in mitigating global warming and reaching carbon neutrality targets,although the drivers of net ecosystem productivity(NEP)under combined human and environmental pressures remain poorly understood.In this study,we analyzed the spatiotemporal evolution of NEP in the Horqin Sandy Land,China from 2000 to 2020,and observed the variation in NEP across different land use types.We further identified and quantified the effects of human activities,topographical features,climatic conditions,and soil properties on NEP through the application of structural equation modeling(SEM)and boosted regression trees(BRT).The results showed that the multi-year average NEP ranged from–137.79 to 461.96 g C/m^(2) in the Horqin Sandy Land,with 88.21%of the area showing a significant increasing trend.Among different land use types,forestland exhibited the highest NEP values,followed by cropland,grassland,impervious land,and unused land.The NEP in carbon sink areas was primarily regulated by potential evapotranspiration(negatively correlated)and precipitation(positively correlated).Slope was identified as the most significant positive determinant in carbon source areas.Forestland exhibited climate–topography interactions driving NEP,whereas cropland and grassland relied on temperature;unused land and impervious land were susceptible to land use/cover change and human footprint.This study has significant implications for maintaining the carbon sink function and promoting ecological engineering programs that aim to enhance the capacity of terrestrial carbon sinks in the semi-arid agro-pastoral ecotone.展开更多
Ports are crucial to the economy of many nations;thus, numerous studies have been conducted on port efficiency and productivity. This study analyses the efficiency and productivity of some major global ports namely, P...Ports are crucial to the economy of many nations;thus, numerous studies have been conducted on port efficiency and productivity. This study analyses the efficiency and productivity of some major global ports namely, Port of Singapore, Rotterdam, Antwerp and Durban. The main objectives of this study are to determine the level of operational efficiency of the mentioned ports, measure and evaluate the ports’ productivity changes and lastly to investigate the factors influencing the productivity changes of the ports studied. To achieve these objectives, Data Envelopment Analysis (DEA-BCC) model was used to determine the technical and operational efficiencies of the ports and Malmquist productivity index was employed to calculate the various productivity levels. The results of the study can guide stakeholders to formulate their operational strategies for port efficiency and productivity. The study also has policy suggestions that are uniquely targeted to Africa’s issues and potential.展开更多
The Qinghai-Tibet Plateau(QTP)has three main grassland types:alpine meadow,alpine steppe,and alpine desert steppe.In this study,we asked how plant productivity and species diversity vary with altitude,longitude and la...The Qinghai-Tibet Plateau(QTP)has three main grassland types:alpine meadow,alpine steppe,and alpine desert steppe.In this study,we asked how plant productivity and species diversity vary with altitude,longitude and latitude in alpine grasslands of the QTP.We then identified the environmental factors that drive these observed patterns of plant productivity and species diversity.We found that although plant productivity and species diversity varied greatly across large-scale longitudinal and latitudinal gradients,these changes were strongest across the longitudinal gradient.This finding indicates that moisture rather than temperature has the greatest impact on plant productivity and species diversity of the alpine grasslands in the QTP.We also found that besides soil and climate factors,partial pressure of carbon dioxide(pCO_(2))also has significant effects on plant productivity,and barometric pressure and partial pressure of oxygen(pO_(2))also have significant effects on species diversity.Furthermore,the relationship between the biomass of grassland-dominant species and species diversity was affected by the spatial scale at which these factors were studied.Our study provides new insights into the interconnections between plant productivity and species diversity and the major factors that influence alpine grasslands.It also provides a scientific basis for the maintenance of plant diversity and ecosystem functions in hypoxic(low-oxygen)regions.展开更多
This paper examines the impact of digital intelligence transformation on new quality productivity in enterprises in Fujian Province.It highlights the challenges these enterprises face,such as limited talent and infras...This paper examines the impact of digital intelligence transformation on new quality productivity in enterprises in Fujian Province.It highlights the challenges these enterprises face,such as limited talent and infrastructure,in adopting technologies like cloud computing,big data,and artificial intelligence.The research finds that digital intelligence can enhance innovation,efficiency,and market adaptability,driving significant improvements in productivity.The study emphasizes the need for organizational changes and government support to overcome barriers and accelerate transformation,offering valuable insights for both academia and industry.展开更多
Bangladesh’s principal grain,rice,is essential to the nation’s agricultural economy and food security.In light of the obstacles and possibilities for increasing domestic output,this study looks at Bangladesh’s food...Bangladesh’s principal grain,rice,is essential to the nation’s agricultural economy and food security.In light of the obstacles and possibilities for increasing domestic output,this study looks at Bangladesh’s food productivity and degree of self-sufficiency in rice production.Even though the nation has made significant progress in rice production,problems including population growth,land degradation,climate change,and poor infrastructure still have an impact on total productivity.To examine the trajectory of Bangladesh’s agricultural sector from 1973 to 2023 through the following economic lenses:agricultural input use,GDP contribution,employment rate,trade trends,critical development indicators,and domestic rice demand and production.The data were chosen based on their accessibility,geographical context,relevance to the study’s aims,and time constraints.According to this study,rice production increased from 9.9 million tons in 1973 to 39.1 million tons in 2023,demonstrating the nation’s continuous efforts to increase agricultural output to satisfy rising market demand.展开更多
The physico-chemical analysis of agricultural soil revealed a textured sandy loam at the surface(0–15 cm),with low organic carbon content(0.42%)and moderate levels of nitrogen(157 kg/ha),phosphorus(15.5 kg/ha),and po...The physico-chemical analysis of agricultural soil revealed a textured sandy loam at the surface(0–15 cm),with low organic carbon content(0.42%)and moderate levels of nitrogen(157 kg/ha),phosphorus(15.5 kg/ha),and potassium(112.6 kg/ha),under neutral pH conditions(pH 7.4).The chickpea variety PG-186 was used to evaluate the impact of nutrient treatments on plant performance and agroecological outcomes.Experimental findings demonstrated a significant influence of various treatments on the growth,yield,and economic returns of chickpea cultivation.The treatment comprising 100%Recommended Dose of Fertilizers(RDF)along with foliar application of 0.6%ZnSO_(4) and 0.9%FeSO_(4) at pre-flowering and pod development stages(T8)resulted in the maximum plant height(15.5 cm,33.7 cm,45.0 cm),dry matter accumulation(27.5 g,245.2 g,1006.7 g/m^(2)),and number of branches per plant(3.47,5.00,and 8.63)at 45,75,and 105 Days After Sowing(DAS),respectively.This treatment also resulted in the highest grain yield(21.00 q/ha)and stover yield(38.67 q/ha),along with a maximum net return of₹95,392/ha and a benefit-to-cost ratio of 2.32.From an ecological standpoint,this study highlights the vital role of balanced and targeted nutrient management in enhancing agroecosystem productivity while maintaining ecological balance.The integration of micronutrient foliar sprays not only boosts nutrient uptake efficiency and plant health but also reduces dependency on excessive chemical fertilizers,thereby mitigating potential negative impacts on soil ecology.Overall,the findings underscore the ecological importance of optimizing nutrient inputs in legume-based cropping systems to foster sustainable agricultural practices that align with ecological resilience,soil health preservation,and environmental stewardship.展开更多
Burundi faces major agricultural constraints, including land fragmentation, soil erosion, limited access to inputs, inadequate infrastructure and demographic pressures that exacerbate food insecurity. In order to addr...Burundi faces major agricultural constraints, including land fragmentation, soil erosion, limited access to inputs, inadequate infrastructure and demographic pressures that exacerbate food insecurity. In order to address the multiple challenges faced by farmers in rural areas, a study on improving agricultural productivity and food security in Burundi through optimized land use and diversified farming practices in agroforestry systems has been carried out. The study area is the communes of Giheta and Rutegama, all located in Burundi’s humid plateau livelihood zone, and involved 164 households grouped in coffee growing cooperatives supervised by the cooperative consortium COCOCA. The study uses a mathematical programming model to determine optimal crop selection based on factors such as production costs, yields and market demand. The findings of the study revealed significant insights into the demographic and socio-economic characteristics of the sampled population. Notably, 98.8% of respondents were engaged in agriculture, confirming the predominantly agricultural nature of Burundi. The results indicated that maize is the most important crop, occupying 33.9% of the average total cultivated area, followed by cassava at 26.5% and bananas at 19.4%. Together, these three crops accounted for a substantial portion of the total cultivated area, highlighting their significance in local agriculture. Beans and potatoes also play a role, occupying 14.4% and smaller areas, respectively. In terms of profitability, the study provides a detailed analysis of profit margins by crop. Bananas emerges as the most profitable crop, with a profit margin of 97.3%, followed closely by cassava at 96.1% and rice at 90.5%. These crops not only offered substantial yields relative to their production costs but also benefited from strong market demand. Other crops, such as beans (71.3%), coffee (70.3%), and vegetables (54.5%), also demonstrated considerable profitability, although they occupied smaller cultivated areas. Conversely, crops like pigeon peas (4.1%), potatoes (7.6%), and sweet potatoes (7.6%) exhibited the lowest profit margins, which may discourage farmers from investing in them unless other incentives, such as ecological benefits or local consumption needs, are present. Regarding the results, we therefore recommend to promote policies supporting agroforestry, improve market access and develop infrastructure to exploit these benefits.展开更多
The restoration of severely fragmented forests requires urgent guidance from succession theory.New theories and methods in plant functional ecology offer novel perspectives on the mechanisms that drive forest successi...The restoration of severely fragmented forests requires urgent guidance from succession theory.New theories and methods in plant functional ecology offer novel perspectives on the mechanisms that drive forest succession and productivity.Here,we established a restoration gradient of seven forest logging periods in temperate forests in China,and conducted systematic surveys on the leaf functional traits of all observed plant species,plant community structure,and soil properties.Inspired by the new concept of two-dimensional plant community traits(i.e.,efficiency and quantity traits)and plant trait networks(PTNs),we explored the adaptation mechanisms of forest communities along a restoration succession and their relationship to productivity.Efficiency and quantity traits initially increased and then stabilized,whereas multi-trait relationships(MR)exhibited fluctuations,with community resource utilization efficiency increasing initially before stabilization.As expected,productivity is poorly explained by either efficiency or quantity traits alone but is substantially better explained by their joint consideration as two-dimensional community traits.Among these,the efficiency and quantity traits of leaf area and leaf dry weight can explain up to 43%of productivity.Furthermore,MR exhibit a time-lag effect on productivity.A structural equation model(SEM)with time-lag analysis showed that efficiency traits,quantity traits,MR,and soil properties explained 64%of the spatial variation in productivity during forest succession.Efficiency and quantity traits directly regulated productivity,whereas soil properties and MR indirectly regulated productivity.Our findings are the first to demonstrate the regulation mechanisms between forest succession and productivity from the framework of efficiency traits-quantity traits-MR,providing theoretical guidance and a reference for ecological restoration,and predicting the spatial variation of forest productivity,especially at small scale.展开更多
Coastal Bangladesh is highly vulnerable to various impacts of climate change,including rising temperatures,unpredictable precipitation,cyclones,droughts,and saltwater intrusion.These factors collectively threaten agri...Coastal Bangladesh is highly vulnerable to various impacts of climate change,including rising temperatures,unpredictable precipitation,cyclones,droughts,and saltwater intrusion.These factors collectively threaten agricultural productivity and food security.This study examines the relationship between farmers’perceptions and observable climatic trends,with a focus on the sustainability of food systems and the promotion of adaptable farming techniques in Bagerhat District,Bangladesh.A mixed-methods strategy was employed,incorporating household surveys(a total of 110 purposively selected farmers),focus group discussions,key informant interviews,and climatic data analysis.The Mann-Kendall test,Sen’s slope estimator,precipitation concentration index(PCI),and standardized rainfall anomaly index(SRAI)were employed to analyze climate trends from 1991 to 2020.The findings showed that more than 70.00%of respondents indicated that summers were becoming warmer,over 50.00%reported that winters were becoming colder,and 63.00%stated that yearly precipitation was decreasing.Farmers reported an increase in flood occurrences and a decline in the predictability of precipitation.Between 2011 and 2019,the output of most rice varieties decreased,with the exception of high-yielding Aman rice and hybrid Boro rice.The results also showed that 60.00%of respondents reported experiencing salinity intrusion,and 57.00%attributed significant yield losses to salinity.Planting salt-tolerant rice varieties(such as BRRI Dhan 67 and Binadhan-10),practicing homestead vegetable cultivation,and moderately integrating shrimp aquaculture were also common adaptive measures.To improve long-term food security in coastal Bangladesh,we suggest growing more salt-tolerant crop varieties,promoting vertical and homestead gardening,enhancing seed systems that are resilient to climate change,and educating farmers on the use of climate-smart farming methods.This study highlights the importance of aligning farmers’perceptions with observed climatic data to design effective adaptation strategies.The findings of this study can guide policy-makers and development practitioners in strengthening climate-resilient agriculture and ensuring long-term food security in coastal Bangladesh.展开更多
The symbiotic relationships between trees and different mycorrhizal fungi affect the biodiversity-ecosystem functioning relationships within forest communities,particularly across different strata from the understorey...The symbiotic relationships between trees and different mycorrhizal fungi affect the biodiversity-ecosystem functioning relationships within forest communities,particularly across different strata from the understorey to the overstorey.However,current research on this relationship has not yet reached a definitive conclusion.In this study,we used regression analyses and structural equation modelling based on a 9-ha mixed broadleaved-Korean pine(Pinus koraiensis)forest plot to explore the effects of different types of mycorrhizal fungi(arbuscular mycorrhizal(AM)and ectomycorrhizal(EM)fungi)on the relationship between tree species diversity and productivity.The study found that the dominance and productivity of AM species increased in the understorey with increasing soil nutrients,whereas the productivity of EM species declined despite increasing diversity.In the overstorey,the productivity of AM species continued to increase with increasing soil nutrients,while that of EM species decreased due to increased competition.As for diversity-productivity relationships(DPRs),in the understorey,both AM and EM tree species demonstrated a positive DPR,suggesting the presence of the niche complementarity effect.In the overstorey,AM species continue to exhibit positive DPR due to their competitive advantage in nutrient-rich environments.In contrast,EM species exhibit negative DPR due to increased competition or less efficient resource use.Additionally,slope influenced forest productivity indirectly by altering the accumulation and distribution of soil nutrients,thereby affecting species distribution and growth conditions.This indirect effect highlights the potential negative impact of slope on soil nutrients within forest ecosystems,as well as its influence on the relationships between biodiversity and ecosystem functions.The study reveals how AM and EM trees influence forest productivity through distinct adaptability and competitive strategies across different forest strata,with a particular emphasis on the strata-dependent effects of mycorrhizal association on DPRs.This finding offers a new perspective on how mycorrhizal types modulate the complex relationships between biodiversity and ecosystem functions across various strata in temperate forests.展开更多
Selecting an appropriate planting density is an effective way to improve crop water productivity(WPC).However, there is a lack of research on the balance between evapotranspiration(ET) partitioning, water consumption,...Selecting an appropriate planting density is an effective way to improve crop water productivity(WPC).However, there is a lack of research on the balance between evapotranspiration(ET) partitioning, water consumption, and grain production under different summer maize planting densities. To close this knowledge gap, a two-year field experiment was conducted in the North China Plain(NCP) to reveal the effects of different planting densities(HD: 100,000 plants ha^(-1);MD: 78,000 plants ha^(-1);LD:56,000 plants ha^(-1)) on ET partitioning, grain yield, and water productivity of summer maize. The water-heat-carbon-nitrogen simulator(WHCNS) model was employed to calculate ET partitioning and perform scenario simulation after calibration and validation. The results showed that compared to the LD treatment, ET of the summer maize and grain yield in the MD and HD treatments significantly increased. Model simulations showed that the ratio of evaporation to ET ranged from 25.6% to 30.7%and reduced as increasing planting densities. Increasing planting density enhanced total transpiration of summer maize more than 20 mm, comparing to LD treatment, and the most significant differences between various planting densities appeared at the mid-growth stage(August 1 to 31). Scenario simulations indicated that grain yield and WPCof summer maize were consistently higher in wet and normal years compared to drought years, exhibiting a trend of initially increasing and then decreasing with increasing planting density. The highest grain yield and WPCof summer maize were observed at a planting density of approximately 80,000 plants ha^(-1). The results provide theoretical support for selecting a summer maize planting density and effectively utilizing agricultural water in the NCP.展开更多
Grassland is a key component of the ecosystem in the Qinghai Lake Basin,China.Understanding the effects of climate change and human activities on grassland productivity significantly improves ecological conservation a...Grassland is a key component of the ecosystem in the Qinghai Lake Basin,China.Understanding the effects of climate change and human activities on grassland productivity significantly improves ecological conservation and promotes sustainable vegetation growth in this area.Based on the net primary productivity(NPP)products of MOD17A3HGF(a moderate-resolution imaging spectroradiometer(MODIS)product that provides annual NPP at 500 m resolution)and meteorological data,we analyzed the spatial and temporal evolution of grassland NPP and its interaction with climate factors in the Qinghai Lake Basin from 2001 to 2022 via partial correlation and trend analysis methods.We also used the deflecting trend residual method and scenario analysis method to quantitatively assess the relative contributions of climatic factors and human activities to grassland NPP.The results revealed that:(1)during the past 22 a,grassland NPP increased considerably,with a gradient change from the northwest to the southeast of the study area;(2)sunshine duration,precipitation,and temperature positively influenced grassland NPP,with sunshine duration exerting a stronger effect on grassland NPP than precipitation and temperature;and(3)98.47%of the grassland in the study area was restored,with an average contribution of 65.00%from human activities and 35.00%from climatic alterations.Compared with climate change,human-induced factors had a greater effect on grassland NPP in this area.The results of the study not only provide important scientific support for ecological restoration and sustainable development of the basin but also offer new ideas for research on similar ecologically fragile areas.展开更多
Nitrification,the process by which ammonia is oxidized to nitrite(ammonia oxidation,AO)and subsequently to nitrate(nitrite oxidation,NO),plays a critical role in the nitrogen cycle by linking the oxidized and reduced ...Nitrification,the process by which ammonia is oxidized to nitrite(ammonia oxidation,AO)and subsequently to nitrate(nitrite oxidation,NO),plays a critical role in the nitrogen cycle by linking the oxidized and reduced forms of nitrogen.This process consumes dissolved oxygen,releases protons,and produces the potent greenhouse gas nitrous oxide(N2O),rendering it highly relevant to various environmental challenges,especially in coastal seas with high anthropogenic nitrogen input.Despite its importance,research has predominantly focused on AO,with fewer studies simultaneously investigating ammonia oxidation rates(AOR)and nitrite oxidation rates(NOR).This study measured AOR and NOR using the 15N tracer technique in the Changjiang(Yangtze)River Estuary(CRE)during the summer of 2022,a season when bottom-water hypoxia occurred frequently.Overall,our findings showed that AOR exceeded NOR across different estuarine conditions.Specifically,higher ammonium and total suspended matter(TSM)concentrations significantly boosted AOR.Notably,despite lower TSM levels compared to previous studies,AOR remained high,suggesting that smaller particles may offer more surface area for ammonia-oxidizing microorganisms.In addition,surface productivity,indicated by the concentration of chlorophyll a(Chl a),was positively correlated with bottom-water nitrification and oxygen consumption.This suggested that increased surface productivity could enhance deep-water microbial nitrification,intensifying oxygen demand and promoting hypoxia,particularly during summer stratification when vertical oxygen replenishment was limited.These findings underscored the complex coupling between particle dynamics,primary production,and microbial nitrogen transformations,and offered important insights for hypoxia mitigation and estuarine ecosystem management.展开更多
Integrating sprinkler with deficit irrigation system is a new approach to improve crop water productivity and ensure water and food security in arid areas of India.This study undertook a field experiment of sprinkler-...Integrating sprinkler with deficit irrigation system is a new approach to improve crop water productivity and ensure water and food security in arid areas of India.This study undertook a field experiment of sprinkler-irrigated cumin(variety GC-4)with a mini-lysimeter setup at an experimental research farm in Jodhpur,India during 2019-2022.Four irrigation treatments T_(1),T_(2),T_(3),and T4 were designed at irrigation water/cumulative pan evaporation(IW/CPE)of 1.0,0.8,0.6,and 0.4,respectively,with three replications.Daily actual crop evapotranspiration(ETc)was recorded and weekly soil moisture was monitored over the crop growth period.Quantities of applied water and drainage from mini-lysimeters were also measured at every irrigation event.Yield of cumin was recorded at crop maturity.Furthermore,change in farmer's net income from 1-hm2 land was computed based on the cost of applying irrigation water and considering yield variations among the treatments.Results indicated the highest mean seasonal actual ETc(371.7 mm)and cumin yield(952.47 kg/hm2)under T_(1)(with full irrigation).Under T_(2),T_(3),and T4,the seasonal actual ETc decreased by 10.4%,27.6%,and 41.3%,respectively,while yield declined by 5.0%,28.4%,and 50.8%,respectively,as compared to the values under T_(1).Furthermore,crop water productivity of 0.272(±0.068)kg/m3 under T_(2)was found relatively higher in comparison to other irrigation treatments,indicating that T_(2)can achieve improved water productivity of cumin in arid areas at an optimum level of deficit irrigation.The results of cost-economics indicated that positive change in farmer's net income from 1-hm2 land was 108.82 USD under T_(2),while T_(3)and T4 showed net losses of 5.33 and 209.67 USD,respectively.Moreover,value of yield response factor and ratio of relative yield reductions to relative ETc deficits were found to be less than 1.00 under T_(2)(0.48),and more than 1.00 under T_(3)(1.07)and T4(1.23).This finding further supports that T_(2)shows the optimized level of deficit irrigation that saves 20.0%of water with sacrificing 5.0%yield in the arid areas of India.Findings of this study provide useful strategies to save irrigation water,bring additional area under irrigation,and improve crop water productivity in India and other similar arid areas in the world.展开更多
Drought significantly constrains vegetation growth and reduces terrestrial carbon sinks.Currently,the spatiotemporal patterns and mechanisms of the differential impacts of soil and meteorological droughts on vegetatio...Drought significantly constrains vegetation growth and reduces terrestrial carbon sinks.Currently,the spatiotemporal patterns and mechanisms of the differential impacts of soil and meteorological droughts on vegetation productivity remain inadequately understood.In this study,we analyzed soil moisture(SM),vapor pressure deficit(VPD),and gross primary productivity(GPP)to investigate their spatiotemporal patterns and the combined effects on GPP over China.The results revealed that:(1)Soil drought and meteorological drought generally exhibited temporally synchronous trends across China.(2)GPP was predominantly affected by the combined and synchronous effects of both SM and VPD,although their effects displayed directional variability differences in certain regions.(3)SM demonstrated a greater relative importance on GPP than VPD across more than half of the regions in China,whereas deciduous broadleaf forests were the only vegetation type primarily affected by VPD.(4)Under the lag effects,both SM and VPD exhibited bidirectional Granger causality with GPP,with the interaction between VPD and GPP proving more pronounced than that of SM.Our research provides valuable insights into the mechanisms through which SM and VPD influence GPP,contributing to improved predictions vegetation productivity and implementing ecological restoration.展开更多
In the new era,the impact of emerging productive forces has permeated every sector of industry.As the core production factor of these forces,data plays a pivotal role in industrial transformation and social developmen...In the new era,the impact of emerging productive forces has permeated every sector of industry.As the core production factor of these forces,data plays a pivotal role in industrial transformation and social development.Consequently,many domestic universities have introduced majors or courses related to big data.Among these,the Big Data Management and Applications major stands out for its interdisciplinary approach and emphasis on practical skills.However,as an emerging field,it has not yet accumulated a robust foundation in teaching theory and practice.Current instructional practices face issues such as unclear training objectives,inconsistent teaching methods and course content,insufficient integration of practical components,and a shortage of qualified faculty-factors that hinder both the development of the major and the overall quality of education.Taking the statistics course within the Big Data Management and Applications major as an example,this paper examines the challenges faced by statistics education in the context of emerging productive forces and proposes corresponding improvement measures.By introducing innovative teaching concepts and strategies,the teaching system for professional courses is optimized,and authentic classroom scenarios are recreated through illustrative examples.Questionnaire surveys and statistical analyses of data collected before and after the teaching reforms indicate that the curriculum changes effectively enhance instructional outcomes,promote the development of the major,and improve the quality of talent cultivation.展开更多
With the rapid development of new quality productivity and the in-depth advancement of digital transformation,vocational college libraries,as important supporting institutions for teaching and research,are facing the ...With the rapid development of new quality productivity and the in-depth advancement of digital transformation,vocational college libraries,as important supporting institutions for teaching and research,are facing the dual challenges of service model transformation and capacity improvement.Based on the changes in the demand for digital academic services under the background of new quality productivity,this paper systematically analyzes the current situation and problems of the digital academic service capabilities of librarians in vocational colleges,constructs a capability model including four dimensions:cognitive attitude,knowledge reserve,skill application,and communication and sharing,and proposes capability improvement strategies from aspects such as organizational incentives,professional training,service innovation,and technical support.Research shows that librarians in vocational colleges need to comprehensively enhance their digital academic service capabilities through paths such as concept renewal,skill strengthening,service transformation,and environment optimization,in order to adapt to the demands of educational reform in the era of new quality productivity.展开更多
This study aimed to model and identify the most productive cutting methods of tree plantations by comparing a forward felling technique(C)with sideways techniques outside(A and D)or inside cutting edge(B and E).Drone ...This study aimed to model and identify the most productive cutting methods of tree plantations by comparing a forward felling technique(C)with sideways techniques outside(A and D)or inside cutting edge(B and E).Drone video material of each tree was analyzed by comparing time distribution of work phases.The relation between this input data and harvester production data was analyzed by regression models.A quadratic model predicted productiv-ity precisely(R^(2)=0.95)and explained the effective-hour productivity in cutting cycle with dummy variables of har-vesting conditions.The productivity was explained by tree size and cutting cycle time,while effects of operator and harvester were eliminated by statistical analysis.In loblolly pine(Pinus taeda L.)plantations on flat terrain,cutting method B was 4.8 m3/E0h(effective working hour)more productive than method A,and 6.7 m^(3)/E0h than method C.In Sydney blue gum(Eucalyptus saligna Sm.)plantations,cutting method E was 1.8 m^(3)/E0h more productive than cut-ting method D on sloping terrain.Of the time-cycle vari-ables,time consumption of the“moving of tree”changed significantly between the cutting methods,of which the ones that used the sideways felling technique inside cutting edge were most efficient.This quadratic modeling structure can be recommended for precise studies in similar harvesting conditions.展开更多
The net primary productivity(NPP)of forest ecosystems plays a crucial role in regulating the terrestrial carbon cycle under global climate change.While the temporal effect driven by ecosystem processes on NPP variatio...The net primary productivity(NPP)of forest ecosystems plays a crucial role in regulating the terrestrial carbon cycle under global climate change.While the temporal effect driven by ecosystem processes on NPP variations is well-documented,spatial variations(from local to regional scales)remain inadequately understood.To evaluate the scale-dependent effects of productivity,predictions from the Biome-BGC model were compared with moderate-resolution imaging spectroradiometer(MODIS)and biometric NPP data in a large temperate forest region at both local and regional levels.Linear mixed-effect models and variance partitioning analysis were used to quantify the effects of environmental heterogeneity and trait variation on simulated NPP at varying spatial scales.Results show that NPP had considerable predictability at the local scale,with a coefficient of determination(R^(2))of 0.37,but this predictability declined significantly to 0.02 at the regional scale.Environmental heterogeneity and photosynthetic traits collectively explained 94.8%of the local variation in NPP,which decreased to 86.7%regionally due to the reduced common effects among these variables.Locally,the leaf area index(LAI)predominated(34.6%),while at regional scales,the stomatal conductance and maximum carboxylation rate were more influential(41.1%).Our study suggests that environmental heterogeneity drives the photosynthetic processes that mediate NPP variations across spatial scales.Incorporating heterogeneous local conditions and trait variations into analyses could enhance future research on the relationship between climate and carbon cycles at larger scales.展开更多
基金National Key R&D Program of China,No.2022YFF1302401National Natural Science Foundation of China,No.42271007。
文摘Ecosystems along the eastern margin of the Qinghai-Tibet Plateau(EQTP)are highly fragile and extremely sensitive to climate change and human disturbances.To quantitatively assess climate-induced ecosystem responses,this study proposes a Climate-Induced Productivity Index(CIPI)based on the Super Slack-Based Measure(Super-SBM)model using remote sensing data from 2001 to 2020.The results reveal persistently low CIPI values(0.47-0.53)across major ecosystem types,indicating widespread vulnerability to climatic variability.Among these ecosystems,forests exhibit the highest CIPI(0.55),followed by shrublands(0.54),croplands(0.53),grasslands(0.51),and barelands(0.43).The Theil index analysis further demonstrates significant intra-group disparities,suggesting that extreme climatic events amplify CIPI heterogeneity.Moreover,the dominant environmental drivers differ among ecosystem types:the Palmer Drought Severity Index(PDSI)primarily constrains grassland productivity,solar radiation(SRAD)strongly influences shrub and cropland systems,whereas subsurface factors exert greater control in forested regions.This study provides a quantitative framework for evaluating climate-ecosystem interactions and offers a scientific basis for long-term ecological monitoring and security planning across the EQTP.
基金funded by the National Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07101-002)the Discipline Construction Program of ZHANG Huayong,Distinguished Professor of School of Life Sciences,Shandong University(61200082363001).
文摘Vegetation in terrestrial ecosystems as a carbon sink is a crucial factor in mitigating global warming and reaching carbon neutrality targets,although the drivers of net ecosystem productivity(NEP)under combined human and environmental pressures remain poorly understood.In this study,we analyzed the spatiotemporal evolution of NEP in the Horqin Sandy Land,China from 2000 to 2020,and observed the variation in NEP across different land use types.We further identified and quantified the effects of human activities,topographical features,climatic conditions,and soil properties on NEP through the application of structural equation modeling(SEM)and boosted regression trees(BRT).The results showed that the multi-year average NEP ranged from–137.79 to 461.96 g C/m^(2) in the Horqin Sandy Land,with 88.21%of the area showing a significant increasing trend.Among different land use types,forestland exhibited the highest NEP values,followed by cropland,grassland,impervious land,and unused land.The NEP in carbon sink areas was primarily regulated by potential evapotranspiration(negatively correlated)and precipitation(positively correlated).Slope was identified as the most significant positive determinant in carbon source areas.Forestland exhibited climate–topography interactions driving NEP,whereas cropland and grassland relied on temperature;unused land and impervious land were susceptible to land use/cover change and human footprint.This study has significant implications for maintaining the carbon sink function and promoting ecological engineering programs that aim to enhance the capacity of terrestrial carbon sinks in the semi-arid agro-pastoral ecotone.
文摘Ports are crucial to the economy of many nations;thus, numerous studies have been conducted on port efficiency and productivity. This study analyses the efficiency and productivity of some major global ports namely, Port of Singapore, Rotterdam, Antwerp and Durban. The main objectives of this study are to determine the level of operational efficiency of the mentioned ports, measure and evaluate the ports’ productivity changes and lastly to investigate the factors influencing the productivity changes of the ports studied. To achieve these objectives, Data Envelopment Analysis (DEA-BCC) model was used to determine the technical and operational efficiencies of the ports and Malmquist productivity index was employed to calculate the various productivity levels. The results of the study can guide stakeholders to formulate their operational strategies for port efficiency and productivity. The study also has policy suggestions that are uniquely targeted to Africa’s issues and potential.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP),Grant No.2019QZKK0606.
文摘The Qinghai-Tibet Plateau(QTP)has three main grassland types:alpine meadow,alpine steppe,and alpine desert steppe.In this study,we asked how plant productivity and species diversity vary with altitude,longitude and latitude in alpine grasslands of the QTP.We then identified the environmental factors that drive these observed patterns of plant productivity and species diversity.We found that although plant productivity and species diversity varied greatly across large-scale longitudinal and latitudinal gradients,these changes were strongest across the longitudinal gradient.This finding indicates that moisture rather than temperature has the greatest impact on plant productivity and species diversity of the alpine grasslands in the QTP.We also found that besides soil and climate factors,partial pressure of carbon dioxide(pCO_(2))also has significant effects on plant productivity,and barometric pressure and partial pressure of oxygen(pO_(2))also have significant effects on species diversity.Furthermore,the relationship between the biomass of grassland-dominant species and species diversity was affected by the spatial scale at which these factors were studied.Our study provides new insights into the interconnections between plant productivity and species diversity and the major factors that influence alpine grasslands.It also provides a scientific basis for the maintenance of plant diversity and ecosystem functions in hypoxic(low-oxygen)regions.
基金Innovation and Entrepreneurship Training Program of Minjiang University,“Research on the Impact of Digital Intelligence Empowerment on the New Quality Productivity of Specialized and Innovative Enterprises and the Realization Path”(Project No.:202410395029)。
文摘This paper examines the impact of digital intelligence transformation on new quality productivity in enterprises in Fujian Province.It highlights the challenges these enterprises face,such as limited talent and infrastructure,in adopting technologies like cloud computing,big data,and artificial intelligence.The research finds that digital intelligence can enhance innovation,efficiency,and market adaptability,driving significant improvements in productivity.The study emphasizes the need for organizational changes and government support to overcome barriers and accelerate transformation,offering valuable insights for both academia and industry.
文摘Bangladesh’s principal grain,rice,is essential to the nation’s agricultural economy and food security.In light of the obstacles and possibilities for increasing domestic output,this study looks at Bangladesh’s food productivity and degree of self-sufficiency in rice production.Even though the nation has made significant progress in rice production,problems including population growth,land degradation,climate change,and poor infrastructure still have an impact on total productivity.To examine the trajectory of Bangladesh’s agricultural sector from 1973 to 2023 through the following economic lenses:agricultural input use,GDP contribution,employment rate,trade trends,critical development indicators,and domestic rice demand and production.The data were chosen based on their accessibility,geographical context,relevance to the study’s aims,and time constraints.According to this study,rice production increased from 9.9 million tons in 1973 to 39.1 million tons in 2023,demonstrating the nation’s continuous efforts to increase agricultural output to satisfy rising market demand.
文摘The physico-chemical analysis of agricultural soil revealed a textured sandy loam at the surface(0–15 cm),with low organic carbon content(0.42%)and moderate levels of nitrogen(157 kg/ha),phosphorus(15.5 kg/ha),and potassium(112.6 kg/ha),under neutral pH conditions(pH 7.4).The chickpea variety PG-186 was used to evaluate the impact of nutrient treatments on plant performance and agroecological outcomes.Experimental findings demonstrated a significant influence of various treatments on the growth,yield,and economic returns of chickpea cultivation.The treatment comprising 100%Recommended Dose of Fertilizers(RDF)along with foliar application of 0.6%ZnSO_(4) and 0.9%FeSO_(4) at pre-flowering and pod development stages(T8)resulted in the maximum plant height(15.5 cm,33.7 cm,45.0 cm),dry matter accumulation(27.5 g,245.2 g,1006.7 g/m^(2)),and number of branches per plant(3.47,5.00,and 8.63)at 45,75,and 105 Days After Sowing(DAS),respectively.This treatment also resulted in the highest grain yield(21.00 q/ha)and stover yield(38.67 q/ha),along with a maximum net return of₹95,392/ha and a benefit-to-cost ratio of 2.32.From an ecological standpoint,this study highlights the vital role of balanced and targeted nutrient management in enhancing agroecosystem productivity while maintaining ecological balance.The integration of micronutrient foliar sprays not only boosts nutrient uptake efficiency and plant health but also reduces dependency on excessive chemical fertilizers,thereby mitigating potential negative impacts on soil ecology.Overall,the findings underscore the ecological importance of optimizing nutrient inputs in legume-based cropping systems to foster sustainable agricultural practices that align with ecological resilience,soil health preservation,and environmental stewardship.
文摘Burundi faces major agricultural constraints, including land fragmentation, soil erosion, limited access to inputs, inadequate infrastructure and demographic pressures that exacerbate food insecurity. In order to address the multiple challenges faced by farmers in rural areas, a study on improving agricultural productivity and food security in Burundi through optimized land use and diversified farming practices in agroforestry systems has been carried out. The study area is the communes of Giheta and Rutegama, all located in Burundi’s humid plateau livelihood zone, and involved 164 households grouped in coffee growing cooperatives supervised by the cooperative consortium COCOCA. The study uses a mathematical programming model to determine optimal crop selection based on factors such as production costs, yields and market demand. The findings of the study revealed significant insights into the demographic and socio-economic characteristics of the sampled population. Notably, 98.8% of respondents were engaged in agriculture, confirming the predominantly agricultural nature of Burundi. The results indicated that maize is the most important crop, occupying 33.9% of the average total cultivated area, followed by cassava at 26.5% and bananas at 19.4%. Together, these three crops accounted for a substantial portion of the total cultivated area, highlighting their significance in local agriculture. Beans and potatoes also play a role, occupying 14.4% and smaller areas, respectively. In terms of profitability, the study provides a detailed analysis of profit margins by crop. Bananas emerges as the most profitable crop, with a profit margin of 97.3%, followed closely by cassava at 96.1% and rice at 90.5%. These crops not only offered substantial yields relative to their production costs but also benefited from strong market demand. Other crops, such as beans (71.3%), coffee (70.3%), and vegetables (54.5%), also demonstrated considerable profitability, although they occupied smaller cultivated areas. Conversely, crops like pigeon peas (4.1%), potatoes (7.6%), and sweet potatoes (7.6%) exhibited the lowest profit margins, which may discourage farmers from investing in them unless other incentives, such as ecological benefits or local consumption needs, are present. Regarding the results, we therefore recommend to promote policies supporting agroforestry, improve market access and develop infrastructure to exploit these benefits.
基金supported by the National Natural Science Foundation of China(32301362,42301544,32430067)。
文摘The restoration of severely fragmented forests requires urgent guidance from succession theory.New theories and methods in plant functional ecology offer novel perspectives on the mechanisms that drive forest succession and productivity.Here,we established a restoration gradient of seven forest logging periods in temperate forests in China,and conducted systematic surveys on the leaf functional traits of all observed plant species,plant community structure,and soil properties.Inspired by the new concept of two-dimensional plant community traits(i.e.,efficiency and quantity traits)and plant trait networks(PTNs),we explored the adaptation mechanisms of forest communities along a restoration succession and their relationship to productivity.Efficiency and quantity traits initially increased and then stabilized,whereas multi-trait relationships(MR)exhibited fluctuations,with community resource utilization efficiency increasing initially before stabilization.As expected,productivity is poorly explained by either efficiency or quantity traits alone but is substantially better explained by their joint consideration as two-dimensional community traits.Among these,the efficiency and quantity traits of leaf area and leaf dry weight can explain up to 43%of productivity.Furthermore,MR exhibit a time-lag effect on productivity.A structural equation model(SEM)with time-lag analysis showed that efficiency traits,quantity traits,MR,and soil properties explained 64%of the spatial variation in productivity during forest succession.Efficiency and quantity traits directly regulated productivity,whereas soil properties and MR indirectly regulated productivity.Our findings are the first to demonstrate the regulation mechanisms between forest succession and productivity from the framework of efficiency traits-quantity traits-MR,providing theoretical guidance and a reference for ecological restoration,and predicting the spatial variation of forest productivity,especially at small scale.
基金supported by the Research Grant of Military Institute of Science and Technology,Bangladesh。
文摘Coastal Bangladesh is highly vulnerable to various impacts of climate change,including rising temperatures,unpredictable precipitation,cyclones,droughts,and saltwater intrusion.These factors collectively threaten agricultural productivity and food security.This study examines the relationship between farmers’perceptions and observable climatic trends,with a focus on the sustainability of food systems and the promotion of adaptable farming techniques in Bagerhat District,Bangladesh.A mixed-methods strategy was employed,incorporating household surveys(a total of 110 purposively selected farmers),focus group discussions,key informant interviews,and climatic data analysis.The Mann-Kendall test,Sen’s slope estimator,precipitation concentration index(PCI),and standardized rainfall anomaly index(SRAI)were employed to analyze climate trends from 1991 to 2020.The findings showed that more than 70.00%of respondents indicated that summers were becoming warmer,over 50.00%reported that winters were becoming colder,and 63.00%stated that yearly precipitation was decreasing.Farmers reported an increase in flood occurrences and a decline in the predictability of precipitation.Between 2011 and 2019,the output of most rice varieties decreased,with the exception of high-yielding Aman rice and hybrid Boro rice.The results also showed that 60.00%of respondents reported experiencing salinity intrusion,and 57.00%attributed significant yield losses to salinity.Planting salt-tolerant rice varieties(such as BRRI Dhan 67 and Binadhan-10),practicing homestead vegetable cultivation,and moderately integrating shrimp aquaculture were also common adaptive measures.To improve long-term food security in coastal Bangladesh,we suggest growing more salt-tolerant crop varieties,promoting vertical and homestead gardening,enhancing seed systems that are resilient to climate change,and educating farmers on the use of climate-smart farming methods.This study highlights the importance of aligning farmers’perceptions with observed climatic data to design effective adaptation strategies.The findings of this study can guide policy-makers and development practitioners in strengthening climate-resilient agriculture and ensuring long-term food security in coastal Bangladesh.
基金financially supported by the Natural Science Foundation of Heilongjiang Province of China(No.TD2023C006)the Fundamental Research Funds for the Central Universities(No.2572022DS13).
文摘The symbiotic relationships between trees and different mycorrhizal fungi affect the biodiversity-ecosystem functioning relationships within forest communities,particularly across different strata from the understorey to the overstorey.However,current research on this relationship has not yet reached a definitive conclusion.In this study,we used regression analyses and structural equation modelling based on a 9-ha mixed broadleaved-Korean pine(Pinus koraiensis)forest plot to explore the effects of different types of mycorrhizal fungi(arbuscular mycorrhizal(AM)and ectomycorrhizal(EM)fungi)on the relationship between tree species diversity and productivity.The study found that the dominance and productivity of AM species increased in the understorey with increasing soil nutrients,whereas the productivity of EM species declined despite increasing diversity.In the overstorey,the productivity of AM species continued to increase with increasing soil nutrients,while that of EM species decreased due to increased competition.As for diversity-productivity relationships(DPRs),in the understorey,both AM and EM tree species demonstrated a positive DPR,suggesting the presence of the niche complementarity effect.In the overstorey,AM species continue to exhibit positive DPR due to their competitive advantage in nutrient-rich environments.In contrast,EM species exhibit negative DPR due to increased competition or less efficient resource use.Additionally,slope influenced forest productivity indirectly by altering the accumulation and distribution of soil nutrients,thereby affecting species distribution and growth conditions.This indirect effect highlights the potential negative impact of slope on soil nutrients within forest ecosystems,as well as its influence on the relationships between biodiversity and ecosystem functions.The study reveals how AM and EM trees influence forest productivity through distinct adaptability and competitive strategies across different forest strata,with a particular emphasis on the strata-dependent effects of mycorrhizal association on DPRs.This finding offers a new perspective on how mycorrhizal types modulate the complex relationships between biodiversity and ecosystem functions across various strata in temperate forests.
基金supported in part by the Key R&D Program of Shandong Province,China (2023CXGC010703)the National Key Research and Development Program of China (2022YFD2300905-01)the Natural Science Foundation of Shandong Province,China (ZR2021MC123)。
文摘Selecting an appropriate planting density is an effective way to improve crop water productivity(WPC).However, there is a lack of research on the balance between evapotranspiration(ET) partitioning, water consumption, and grain production under different summer maize planting densities. To close this knowledge gap, a two-year field experiment was conducted in the North China Plain(NCP) to reveal the effects of different planting densities(HD: 100,000 plants ha^(-1);MD: 78,000 plants ha^(-1);LD:56,000 plants ha^(-1)) on ET partitioning, grain yield, and water productivity of summer maize. The water-heat-carbon-nitrogen simulator(WHCNS) model was employed to calculate ET partitioning and perform scenario simulation after calibration and validation. The results showed that compared to the LD treatment, ET of the summer maize and grain yield in the MD and HD treatments significantly increased. Model simulations showed that the ratio of evaporation to ET ranged from 25.6% to 30.7%and reduced as increasing planting densities. Increasing planting density enhanced total transpiration of summer maize more than 20 mm, comparing to LD treatment, and the most significant differences between various planting densities appeared at the mid-growth stage(August 1 to 31). Scenario simulations indicated that grain yield and WPCof summer maize were consistently higher in wet and normal years compared to drought years, exhibiting a trend of initially increasing and then decreasing with increasing planting density. The highest grain yield and WPCof summer maize were observed at a planting density of approximately 80,000 plants ha^(-1). The results provide theoretical support for selecting a summer maize planting density and effectively utilizing agricultural water in the NCP.
基金financially supported by the Lanzhou Youth Science and Technology Talent Innovation Project(2023-QN-2)the Gansu Haizhi Plan Project(GSHZJH 12-2025-04)+1 种基金the National Key Research and Development Program of China(2019YFC0507404)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20100101)。
文摘Grassland is a key component of the ecosystem in the Qinghai Lake Basin,China.Understanding the effects of climate change and human activities on grassland productivity significantly improves ecological conservation and promotes sustainable vegetation growth in this area.Based on the net primary productivity(NPP)products of MOD17A3HGF(a moderate-resolution imaging spectroradiometer(MODIS)product that provides annual NPP at 500 m resolution)and meteorological data,we analyzed the spatial and temporal evolution of grassland NPP and its interaction with climate factors in the Qinghai Lake Basin from 2001 to 2022 via partial correlation and trend analysis methods.We also used the deflecting trend residual method and scenario analysis method to quantitatively assess the relative contributions of climatic factors and human activities to grassland NPP.The results revealed that:(1)during the past 22 a,grassland NPP increased considerably,with a gradient change from the northwest to the southeast of the study area;(2)sunshine duration,precipitation,and temperature positively influenced grassland NPP,with sunshine duration exerting a stronger effect on grassland NPP than precipitation and temperature;and(3)98.47%of the grassland in the study area was restored,with an average contribution of 65.00%from human activities and 35.00%from climatic alterations.Compared with climate change,human-induced factors had a greater effect on grassland NPP in this area.The results of the study not only provide important scientific support for ecological restoration and sustainable development of the basin but also offer new ideas for research on similar ecologically fragile areas.
基金The Hainan Provincial Natural Science Foundation of China under contract No.423RC438the Major Science and Technology Plan of Hainan Province under contract No.ZDKJ2021008+1 种基金the National Natural Science Foundation of China under contract Nos 42406041,92251306,42266002,41806062,and 42476032the Open Research Fund of Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention under contract No.GPKLMD2023004.
文摘Nitrification,the process by which ammonia is oxidized to nitrite(ammonia oxidation,AO)and subsequently to nitrate(nitrite oxidation,NO),plays a critical role in the nitrogen cycle by linking the oxidized and reduced forms of nitrogen.This process consumes dissolved oxygen,releases protons,and produces the potent greenhouse gas nitrous oxide(N2O),rendering it highly relevant to various environmental challenges,especially in coastal seas with high anthropogenic nitrogen input.Despite its importance,research has predominantly focused on AO,with fewer studies simultaneously investigating ammonia oxidation rates(AOR)and nitrite oxidation rates(NOR).This study measured AOR and NOR using the 15N tracer technique in the Changjiang(Yangtze)River Estuary(CRE)during the summer of 2022,a season when bottom-water hypoxia occurred frequently.Overall,our findings showed that AOR exceeded NOR across different estuarine conditions.Specifically,higher ammonium and total suspended matter(TSM)concentrations significantly boosted AOR.Notably,despite lower TSM levels compared to previous studies,AOR remained high,suggesting that smaller particles may offer more surface area for ammonia-oxidizing microorganisms.In addition,surface productivity,indicated by the concentration of chlorophyll a(Chl a),was positively correlated with bottom-water nitrification and oxygen consumption.This suggested that increased surface productivity could enhance deep-water microbial nitrification,intensifying oxygen demand and promoting hypoxia,particularly during summer stratification when vertical oxygen replenishment was limited.These findings underscored the complex coupling between particle dynamics,primary production,and microbial nitrogen transformations,and offered important insights for hypoxia mitigation and estuarine ecosystem management.
文摘Integrating sprinkler with deficit irrigation system is a new approach to improve crop water productivity and ensure water and food security in arid areas of India.This study undertook a field experiment of sprinkler-irrigated cumin(variety GC-4)with a mini-lysimeter setup at an experimental research farm in Jodhpur,India during 2019-2022.Four irrigation treatments T_(1),T_(2),T_(3),and T4 were designed at irrigation water/cumulative pan evaporation(IW/CPE)of 1.0,0.8,0.6,and 0.4,respectively,with three replications.Daily actual crop evapotranspiration(ETc)was recorded and weekly soil moisture was monitored over the crop growth period.Quantities of applied water and drainage from mini-lysimeters were also measured at every irrigation event.Yield of cumin was recorded at crop maturity.Furthermore,change in farmer's net income from 1-hm2 land was computed based on the cost of applying irrigation water and considering yield variations among the treatments.Results indicated the highest mean seasonal actual ETc(371.7 mm)and cumin yield(952.47 kg/hm2)under T_(1)(with full irrigation).Under T_(2),T_(3),and T4,the seasonal actual ETc decreased by 10.4%,27.6%,and 41.3%,respectively,while yield declined by 5.0%,28.4%,and 50.8%,respectively,as compared to the values under T_(1).Furthermore,crop water productivity of 0.272(±0.068)kg/m3 under T_(2)was found relatively higher in comparison to other irrigation treatments,indicating that T_(2)can achieve improved water productivity of cumin in arid areas at an optimum level of deficit irrigation.The results of cost-economics indicated that positive change in farmer's net income from 1-hm2 land was 108.82 USD under T_(2),while T_(3)and T4 showed net losses of 5.33 and 209.67 USD,respectively.Moreover,value of yield response factor and ratio of relative yield reductions to relative ETc deficits were found to be less than 1.00 under T_(2)(0.48),and more than 1.00 under T_(3)(1.07)and T4(1.23).This finding further supports that T_(2)shows the optimized level of deficit irrigation that saves 20.0%of water with sacrificing 5.0%yield in the arid areas of India.Findings of this study provide useful strategies to save irrigation water,bring additional area under irrigation,and improve crop water productivity in India and other similar arid areas in the world.
基金National Key Research and Development Program,No.2021xjkk0303。
文摘Drought significantly constrains vegetation growth and reduces terrestrial carbon sinks.Currently,the spatiotemporal patterns and mechanisms of the differential impacts of soil and meteorological droughts on vegetation productivity remain inadequately understood.In this study,we analyzed soil moisture(SM),vapor pressure deficit(VPD),and gross primary productivity(GPP)to investigate their spatiotemporal patterns and the combined effects on GPP over China.The results revealed that:(1)Soil drought and meteorological drought generally exhibited temporally synchronous trends across China.(2)GPP was predominantly affected by the combined and synchronous effects of both SM and VPD,although their effects displayed directional variability differences in certain regions.(3)SM demonstrated a greater relative importance on GPP than VPD across more than half of the regions in China,whereas deciduous broadleaf forests were the only vegetation type primarily affected by VPD.(4)Under the lag effects,both SM and VPD exhibited bidirectional Granger causality with GPP,with the interaction between VPD and GPP proving more pronounced than that of SM.Our research provides valuable insights into the mechanisms through which SM and VPD influence GPP,contributing to improved predictions vegetation productivity and implementing ecological restoration.
文摘In the new era,the impact of emerging productive forces has permeated every sector of industry.As the core production factor of these forces,data plays a pivotal role in industrial transformation and social development.Consequently,many domestic universities have introduced majors or courses related to big data.Among these,the Big Data Management and Applications major stands out for its interdisciplinary approach and emphasis on practical skills.However,as an emerging field,it has not yet accumulated a robust foundation in teaching theory and practice.Current instructional practices face issues such as unclear training objectives,inconsistent teaching methods and course content,insufficient integration of practical components,and a shortage of qualified faculty-factors that hinder both the development of the major and the overall quality of education.Taking the statistics course within the Big Data Management and Applications major as an example,this paper examines the challenges faced by statistics education in the context of emerging productive forces and proposes corresponding improvement measures.By introducing innovative teaching concepts and strategies,the teaching system for professional courses is optimized,and authentic classroom scenarios are recreated through illustrative examples.Questionnaire surveys and statistical analyses of data collected before and after the teaching reforms indicate that the curriculum changes effectively enhance instructional outcomes,promote the development of the major,and improve the quality of talent cultivation.
基金China Transportation Education Research Society Educational Science Research Topic“Research on Improving the Quality of Part-time Teachers in Transportation Vocational Colleges under the Background of New Quality Productivity”(JT2024YB245)。
文摘With the rapid development of new quality productivity and the in-depth advancement of digital transformation,vocational college libraries,as important supporting institutions for teaching and research,are facing the dual challenges of service model transformation and capacity improvement.Based on the changes in the demand for digital academic services under the background of new quality productivity,this paper systematically analyzes the current situation and problems of the digital academic service capabilities of librarians in vocational colleges,constructs a capability model including four dimensions:cognitive attitude,knowledge reserve,skill application,and communication and sharing,and proposes capability improvement strategies from aspects such as organizational incentives,professional training,service innovation,and technical support.Research shows that librarians in vocational colleges need to comprehensively enhance their digital academic service capabilities through paths such as concept renewal,skill strengthening,service transformation,and environment optimization,in order to adapt to the demands of educational reform in the era of new quality productivity.
文摘This study aimed to model and identify the most productive cutting methods of tree plantations by comparing a forward felling technique(C)with sideways techniques outside(A and D)or inside cutting edge(B and E).Drone video material of each tree was analyzed by comparing time distribution of work phases.The relation between this input data and harvester production data was analyzed by regression models.A quadratic model predicted productiv-ity precisely(R^(2)=0.95)and explained the effective-hour productivity in cutting cycle with dummy variables of har-vesting conditions.The productivity was explained by tree size and cutting cycle time,while effects of operator and harvester were eliminated by statistical analysis.In loblolly pine(Pinus taeda L.)plantations on flat terrain,cutting method B was 4.8 m3/E0h(effective working hour)more productive than method A,and 6.7 m^(3)/E0h than method C.In Sydney blue gum(Eucalyptus saligna Sm.)plantations,cutting method E was 1.8 m^(3)/E0h more productive than cut-ting method D on sloping terrain.Of the time-cycle vari-ables,time consumption of the“moving of tree”changed significantly between the cutting methods,of which the ones that used the sideways felling technique inside cutting edge were most efficient.This quadratic modeling structure can be recommended for precise studies in similar harvesting conditions.
基金supported by the National Key R&D Program of China(No.2023YFF1304001-01)the Science and Technology Project of the Department of Transportation of Heilongjiang Province(No.HJK2023B024-3)the Program of National Natural Science Foundation of China(No.32371870).
文摘The net primary productivity(NPP)of forest ecosystems plays a crucial role in regulating the terrestrial carbon cycle under global climate change.While the temporal effect driven by ecosystem processes on NPP variations is well-documented,spatial variations(from local to regional scales)remain inadequately understood.To evaluate the scale-dependent effects of productivity,predictions from the Biome-BGC model were compared with moderate-resolution imaging spectroradiometer(MODIS)and biometric NPP data in a large temperate forest region at both local and regional levels.Linear mixed-effect models and variance partitioning analysis were used to quantify the effects of environmental heterogeneity and trait variation on simulated NPP at varying spatial scales.Results show that NPP had considerable predictability at the local scale,with a coefficient of determination(R^(2))of 0.37,but this predictability declined significantly to 0.02 at the regional scale.Environmental heterogeneity and photosynthetic traits collectively explained 94.8%of the local variation in NPP,which decreased to 86.7%regionally due to the reduced common effects among these variables.Locally,the leaf area index(LAI)predominated(34.6%),while at regional scales,the stomatal conductance and maximum carboxylation rate were more influential(41.1%).Our study suggests that environmental heterogeneity drives the photosynthetic processes that mediate NPP variations across spatial scales.Incorporating heterogeneous local conditions and trait variations into analyses could enhance future research on the relationship between climate and carbon cycles at larger scales.
