[Objective] This study aimed at investigating the effects of consumption of potassium fertilizer on production and biological characteristics of rape and utilizing efficiency of potassium fertilizer.[Method] Taking 0 ...[Objective] This study aimed at investigating the effects of consumption of potassium fertilizer on production and biological characteristics of rape and utilizing efficiency of potassium fertilizer.[Method] Taking 0 kg/hm2 as control,nine consumptions of potassium fertilizer were designed for the experiment using single factor randomized block design with three replications and field experiment in nine rape-producing areas with different ecological types in Yunnan Province.[Result] Appropriately applying potassium fertilizer in Yunnan Province could improve the rapeseed production,the rape production could achieve 3 983-4 151 kg when applied 150-180 kg/hm2 of K2O,which had increased by 4.7-9.1% compared with the control and attained the peak in K165 treatment.When applied 1 kg of K2O,the rapeseed production could enhance 559 kg,the net profit could reach 1 229 yuan/hm2 and the partial productivity of potassium fertilizer could attain 31.32 kg/kg K2O and 3.7 kg/kg K2O,respectively.Applying potassium fertilizer could promote the growth of rape and increase rapeseed production.[Conclusion] The recommended optimal consumptions of potassium fertilizer with high production and high efficiency for rape in Yunnan Province were ranged between 150 and 180 kg K2O/hm2.However,comprehensively considering production and efficiency factors,the consumption of potassium fertilizer in Yunnan Province was around 73.9 kg/hm2,which should be appropriately increased to around 100.0 kg/hm2 in Longchuan,Yulong,Linxiang and other producing areas with similar conditions.展开更多
The utilization of ironsand for preparing oxidized pellets poses challenges,including slow oxidation and low consolidation strength.The effects and function mechanisms of high-pressure grinding roll(HPGR)pretreatment ...The utilization of ironsand for preparing oxidized pellets poses challenges,including slow oxidation and low consolidation strength.The effects and function mechanisms of high-pressure grinding roll(HPGR)pretreatment on the oxidation and consolidation of ironsand pellets were investigated,and the energy utilization efficiency of HPGR with different roller pressure intensities was evaluated.The results indicate that HPGR pretreatment at 8 MPa improves the ironsand properties,with the specific surface area increasing by 740 cm^(2) g^(-1) and mechanical energy storage increasing by 2.5 kJ mol^(-1),which is conducive to oxidation and crystalline connection of particles.As roller pressure intensity increases to 16 MPa,more mechanical energy of HPGR is applied for crystal activation,with mechanical energy storage further rising by 18.1 kJ mol^(-1).The apparent activation energy for pellet oxidation initially decreases and then increases,reaching a minimum at 12 MPa.Simultaneously,the roasted pellets porosity decreases by 2.8%,while the compressive strength increases by 789 N.At higher roller pressure intensity,the densely connected structure between particles impedes gas diffusion within the pellets,diminishing the beneficial effects of HPGR on pellet oxidation.Moreover,excessive roller pressure intensity decreases the HPGR energy utilization efficiency.The optimal HPGR roller pressure intensity for ironsand is 12 MPa,at which the specific surface area increases by 790 cm^(2) g^(-1),mechanical energy storage increases by 10.6 kJ mol^(-1),the compressive strength of roasted pellets rises to 2816 N,and the appropriate preheating and roasting temperatures decrease by 250 and 125°C,respectively.展开更多
Semitransparent organic photovoltaics(ST-OPVs)for building integration represent a pivotal direction in the development of photovoltaic industry.Solution-processed silver nanowires(AgNWs)are considered promising candi...Semitransparent organic photovoltaics(ST-OPVs)for building integration represent a pivotal direction in the development of photovoltaic industry.Solution-processed silver nanowires(AgNWs)are considered promising candidates for transparent electrodes in semitransparent devices due to their high transparency-conductivity-efficiency merit,large-scale processability,and low cost.In this work,we develop two solution-processed organic–inorganic hybrid electrodes,named AgNWs-PD and AgNWsPC,utilizing AgNWs as the conductive framework and aliphatic amine-functionalized perylene-diimide(PDINN)as the sandwiched material,while AgNWs-PC exhibits significantly improved electrical conductivity and enhanced contact area with the underlying electron transport layer.The optimized device achieves a power conversion efficiency of 9.45%with an open circuit voltage of 0.846 V,a high filling factor of 75.4%,and an average visible transmittance(AVT)of 44.0%,delivering an outstanding light utilization efficiency(LUE)of 4.16%,which is the highest reported value for all solution-processed ST-OPVs.In addition,by coupling a 30-nm tellurium dioxide atop AgNWs-PC,the bifaciality factor of derivative devices improves from 73.7%to 99.4%,while maintaining a high bifacial LUE over 3.7%.Our results emphasize the superiority and effectiveness of PDINN-sandwiched AgNWs electrodes for highperformance and all solution-processed ST-OPVs.展开更多
The effects of micro-ridge-furrow planting(MR)on yield and the efficiency of light,water,and thermal resource use in rapeseed were tested in a three-year field experiment comparing MR to conventional flat planting.MR ...The effects of micro-ridge-furrow planting(MR)on yield and the efficiency of light,water,and thermal resource use in rapeseed were tested in a three-year field experiment comparing MR to conventional flat planting.MR enhanced canopy heterogeneity by altering the leaf angle between plants on ridges and furrows.The heterogeneous canopy environment increased intercepted photosynthetic active radiation,alleviated canopy temperature stress,and optimized canopy humidity,leading to improvements in light-nitrogen matching and net photosynthetic rate.Consequently,dry matter and yield increased by 13.0%and 11.0%,respectively,while radiation,thermal,and precipitation utilization efficiency increased by 12.3%-16.2%.The corresponding improvements in yield and resource use efficiency were attributed to a heterogeneous canopy environment that improved microclimatic conditions.展开更多
With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared...With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared at the seedling stage.P-efficient cultivars showed root morphological adaptation,high P uptake activity,and greater phospholipid degradation under low P stress.Improving root morphological adaptation and reducing lipid-P allocation could allow increasing PUE in rapeseed seedlings.展开更多
Low-affinity nitrate transporter genes have been identified in subfamilies 4-8 of the rice nitrate transporter 1(NRT1)/peptide transporter family(NPF),but the OsNPF3 subfamily responsible for nitrate and phytohormone ...Low-affinity nitrate transporter genes have been identified in subfamilies 4-8 of the rice nitrate transporter 1(NRT1)/peptide transporter family(NPF),but the OsNPF3 subfamily responsible for nitrate and phytohormone transport and rice growth and development remains unknown.In this study,we described OsNPF3.1 as an essential nitrate and phytohormone transporter gene for rice tillering and nitrogen utilization efficiency(NUtE).OsNPF3.1 possesses four major haplotypes of its promoter sequence in 517 cultivars,and its expression is positively associated with tiller number.Its expression was higher in the basal part,culm,and leaf blade than in other parts of the plant,and was strongly induced by nitrate,abscisic acid(ABA)and gibberellin 3(GA_3)in the root and shoot of rice.Electrophysiological experiments demonstrated that OsNPF3.1 is a pH-dependent low-affinity nitrate transporter,with rice protoplast uptake assays showing it to be an ABA and GA_3 transporter.OsNPF3.1 overexpression significantly promoted ABA accumulation in the roots and GA accumulation in the basal part of the plant which inhibited axillary bud outgrowth and rice tillering,especially at high nitrate concentrations.The NUtE of OsNPF3.1-overexpressing plants was enhanced under low and medium nitrate concentrations,whereas the NUtE of OsNPF3.1 clustered regularly interspaced short palindromic repeats(CRISPR)plants was increased under high nitrate concentrations.The results indicate that OsNPF3.1 transports nitrate and phytohormones in different rice tissues under different nitrate concentrations.The altered OsNPF3.1 expression improves NUtE in the OsNPF3.1-overexpressing and CRISPR lines at low and high nitrate concentrations,respectively.展开更多
[Objective] This study was to investigate the effects of different irrigation amount on water consumption and water use efficiency of greenhouse cucumber.[Method]Under the condition of drip irrigation with different w...[Objective] This study was to investigate the effects of different irrigation amount on water consumption and water use efficiency of greenhouse cucumber.[Method]Under the condition of drip irrigation with different water amounts in sunlight greenhouse of the arid areas in Ningxia,the soil water was measured and the water consumption of crop was calculated.[Result]When irrigation amount was 563 mm,the water consumption as a whole gradually increased with the delay of growth period,reached peak during the thriving stage of fruit setting,and then gradually declined;in each treatment,the daily water consumption increased with the increasing of irrigation amount during each growth period.However,the consumption of soil moisture reduced with the significant increase of irrigation.563 mm of irrigation amount could meet the water requirements of cucumber and began to add water to soil,and water utilization efficiency could reach 33.4 kg/m3.[Conclusion]The research had provided theoretical basis for water management in the production process of greenhouse cucumber.展开更多
[Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and ut...[Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and utilization efficiency for mid-season hybrid rice.[Method] By using mid-season rice varieties II-you 7 and Yuxiangyou203 as the experimental materials,field experiment was conducted at seven ecological sites in four provinces or cities in Southwestern China in 2009.A total of four nitrogen application levels were set as follows：by using 75 kg/hm2 of P2O5 and 75 kg/hm2 of K2O as the base fertilizer,extra 0,90,150 and 210 kg/hm2 of nitrogen fertilizer（in which,base fertilizer,base-tillering fertilizer and base-earing fertilizer respectively accounted for 60%,20% and 20%.） was applied,respectively.In the split-plot design,fertilizer was considered as the main factor while rice variety was taken as the secondary factor.A total of eight treatments were set with three replications.[Result] Highly significant differences of grain yield were found among seven locations,two varieties,four nitrogen application levels,interactions of site × variety and site × nitrogen application level,but the interaction of variety ×nitrogen application level had no significant influence on rice yield.There were highly significant effects of site,varieties and nitrogen application level on dry matter production,nitrogen content,nitrogen utilization efficiency.Highly significant negative correlations between uptake efficiency and utilization efficiency for nitrogen were found;and multiple stepwise regression analysis showed that nitrogen uptake-utilization efficiency were significantly influenced by different ecological sites,chemical quality of soil and the levels of nitrogen application.[Conclusion] The research will provide theoretical and practical basis for the highly efficient application of nitrogen in mid-season hybrid rice cultivation.展开更多
Against the backdrop of active global responses to climate change and the accelerated green and low-carbon energy transition,the co-optimization and innovative mechanism design of multimodal energy systems have become...Against the backdrop of active global responses to climate change and the accelerated green and low-carbon energy transition,the co-optimization and innovative mechanism design of multimodal energy systems have become a significant instrument for propelling the energy revolution and ensuring energy security.Under increasingly stringent carbon emission constraints,how to achieve multi-dimensional improvements in energy utilization efficiency,renewable energy accommodation levels,and system economics-through the intelligent coupling of diverse energy carriers such as electricity,heat,natural gas,and hydrogen,and the effective application of market-based instruments like carbon trading and demand response-constitutes a critical scientific and engineering challenge demanding urgent solutions.展开更多
A lab-scale adiabatic reactor has been self-made to characterize the coupled properties of heat and reactions during the co-thermal-processing of coal and biomass with steam or steam/O_(2) gasification agents.Results ...A lab-scale adiabatic reactor has been self-made to characterize the coupled properties of heat and reactions during the co-thermal-processing of coal and biomass with steam or steam/O_(2) gasification agents.Results showed that the synergistic effects caused by heat transfer between corncob and coal at different mixing ratios were heavily determined by coal rank and gasification agent.During steam co-processing,the heat transfer from corncob char to adjacent bituminous coal char promoted the water-gas reaction on coal char and contributed to synergistic effects;the heat transfer from anthracite char to adjacent corncob char reduced the kinetic rate of the water-gas reaction on coal char and contributed to inhibitory effects,and the inhibitory effect caused by heat transfer was greater than the promotion effects of biomass mass transfer.The introduction of O_(2) diminished the impact of inter-particle heat transfer and altered the intensity of synergy,decreasing the values of synergy factor of bituminous coal/corncob blends by 17%and increasing the value of synergy factor of anthracite/corncob blends by 142.5%.This study provides sufficient support for the process conditions selection for the production of syngas with specific H_(2)/CO molar ratios and the desired level of gasification performance.展开更多
Straw return has demonstrated significant potential for enhancing carbon(C)sequestration and nitrogen(N)uptake while concurrently promoting plant productivity.However,the specific transport and distribution of C produ...Straw return has demonstrated significant potential for enhancing carbon(C)sequestration and nitrogen(N)uptake while concurrently promoting plant productivity.However,the specific transport and distribution of C produced by photosynthesis and exogenous N within the rice plant-soil system under straw return remains unclear.A long-term straw return pot trial experiment was conducted in a double cropping rice system,incorporating treatments of inorganic fertilizer application with straw removal(F),straw burning and ash return with reducing inorganic fertilizers(SBR),and straw return with reducing inorganic fertilizers(SR)to investigate C sequestration and exogenous N uptake using ^(13)C pulse and ^(15)N isotope tracer techniques.The SR treatment had significantly higher soil ^(13)C abundance,by 24.4 and 25.4%,respectively,^(13)C concentrations in aboveground plant parts,by 18.4 and 35.8%respectively,and ^(15)N concentrations in rice panicles,by 12.8 and 34.3%than the SBR and F treatments.This enhancement contributed to a higher total organic C concentration and increased rice grain yield in the SR treatment.Furthermore,the SR treatment had significantly higher photosynthetic C,by 9.8%,which was directly transferred to soil C.The SR treatment had a higher distribution of photosynthetic C in the leaves and stems,but a lower distribution in the panicle compared to the SBR treatment.This finding is advantageous for sequestering photosynthetic C into the soil through straw return;conversely,opposite trends were observed in ^(15)N distribution.In addition,rice plants in the SR treatment had increased N uptake from urea and soil N sources,enhancing N recovery by 9.2 and 12.5%,respectively,and reducing soil N residues.Correlation analysis showed that the SR treatment increased the concentrations of ^(13)C in leaves and roots while decreasing the ^(15)N abundance in all rice organs,thereby contributing to an increase in rice yield.The partial least square path model suggested that the increase in rice yield under the SR treatment was primarily linked to ^(13)C accumulation within the rice plant-soil system.The results suggest that straw return increases the sequestration of photosynthetic C and exogenous N in the rice plant-soil system and increases N utilization efficiency,which subsequently improves both rice and soil productivity.展开更多
Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N ferti...Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.展开更多
Based on provincial panel data of water footprint and grey water footprint, and with the help of data envelopment analysis model considering and without considering the unde- sirable output, this paper estimates the w...Based on provincial panel data of water footprint and grey water footprint, and with the help of data envelopment analysis model considering and without considering the unde- sirable output, this paper estimates the water resources utilization efficiency in China from 1997 to 2011. The spatial weighting matrix based on economy-spatial distance function is established to discuss spatial autocorrelation of water resources utilization efficiency. With the help of absolute/3-convergence model, this paper concludes that there exists/%convergence in the water resources utilization efficiency. Under the conditions of considering and without considering the undesirable output, it takes about 52.6 and 5.6 years respectively to achieve the extent of half of convergence. By mean of the spatial Durbin econometric model, this paper studies spatial spillover effects of the provincial water resources utilization efficiency in China. The results are as follows. 1） With considering and without considering the undesir- able output, there is significant spatial correlation in provincial water resource efficiency in China. 2） Under the two cases, the spatial autoregressive coefficients （p） are 0.278 and 0.507 respectively, at 1% significance level. There exist the spatial spillover effects of provin- cial water resources utilization efficiency. 3） With considering the undesirable output, these factors of the education funds, the transportation infrastructure, and the industrial and agri- cultural water consumption proportion have positive impacts. These factors of foreign direct investment, the industry value-added water consumption per ten thousand yuan, per capita water consumption, and the total precipitation have negative impacts. 4） Without considering the undesirable output, the factor of GDP per laborer has a greater positive significant influ- ence on the water resources utilization efficiency. However the facts of industry value-added water consumption in ten thousand yuan and the transportation infrastructure have no sig- nificant influence. 5） Regardless of undesirable output of water resources utilization efficiency the assessment of the present real water resources utilization in China will be distorted and policy-making will be misled. The water efficiency measure considering environmental factors （such as gray water footprint） is more reasonable.展开更多
The efficient use of water resources directly affects environmental, social, and economic development; therefore, it has a significant impact on urban populations. A slacks-based measure for data envelopment analysis ...The efficient use of water resources directly affects environmental, social, and economic development; therefore, it has a significant impact on urban populations. A slacks-based measure for data envelopment analysis （SBM-DEA） has been widely used in energy efficiency and environmental efficiency analyses in recent years. Based on this model, data from 316 cities were examined and a category method was employed involving three different sorting techniques to empirically evaluate the efficiency of urban water re- source utilization in China between 2000 and 2012. The overall efficiency （OE） of urban water resource utilization in China was initially low, but has improved over the past decade. The scale efficiency （SE） was higher than the pure technological efficiency （PTE）; PTE is a major determining factor of OE, and has had an increasingly significant effect. The efficiency of water resource utilization varied ac- cording to the region, urban scale, and economic function. The OE score for the eastern China was higher than for the rest of the region, and the OE score for the western China was higher than for the central China. The OE score for urban water resource utilization has improved with urban expansion, except in the case of small cities. The SE showed an inverted U-shaped＇ trend with increasing urban expansion. The OE of urban water utilization in comprehensive functional cities was greater than in economic specialization cities, and was greater in heavy industry specialization cities than in other specialization cities. This study contributes to the field of urban water resource management by examining variations in efficiency with urban ~ezle展开更多
In order to establish methods for indentification and screening of rice genotypes with high nitrogen （N） efficiency, N absorption efficiency （NAE）, N utilization efficiency （NUE） and N harvest index （NHI） in t...In order to establish methods for indentification and screening of rice genotypes with high nitrogen （N） efficiency, N absorption efficiency （NAE）, N utilization efficiency （NUE） and N harvest index （NHI） in ten rice genotypes were investgated at the elongation, booting, heading and maturity stages under six N levels in a pot experiment with soil-sand mixtures at various ratios. NAE in various rice genotypes firstly increased, peaked under a medium nitrogen rate of 0.177 g/kg and then decreased, but NUE and NHI always decreased with increasing nitrogen levels. NAE in various rice genotypes ever increased with growing process and NUE indicated a descending tendency of elongation stage〉heading stage〉maturity stage〉booting stage. N level influenced rice NAE, NUE and NHI most, followed by genotype, and the both effects were significant at 0.01 level. In addition, the interaction effects of genotype and nitrogen level on rice NAE and NUE were significant at 0.01 level, but not significant on rice NHI. Because the maximum differences of NAE and NUE were found at the elongation stage, it was thought to be the most suitable stage for identification and screening these two paremeters. Therefore, the optimum conditions for identification and screening of rice NAE, NUE and NHI in a pot experiment were the nitrogen rate of 0.157 g/kg at the elongation stage, low nitrogen at the elongation stage, and the nitrogen rate of 0.277 g/kg at the maturity stage, respectively.展开更多
Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to in...Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to investigate the effects of dietary xylooligosaccharides(XOS)and exogenous enzyme(EXE)supplementation on milk production,nutrient digestibility,enteric CH_(4) emissions,energy utilization efficiency of lactating Jersey dairy cows.Forty-eight lactating cows were randomly assigned to one of 4 treatments:(1)control diet(CON),(2)CON with 25 g/d XOS(XOS),(3)CON with 15 g/d EXE(EXE),and(4)CON with 25 g/d XOS and 15 g/d EXE(XOS+EXE).The 60-d experimental period consisted of a 14-d adaptation period and a 46-d sampling period.The enteric CO_(2)and CH_(4) emissions and O2 consumption were measured using two GreenFeed units,which were further used to determine the energy utilization efficiency of cows.Results Compared with CON,cows fed XOS,EXE or XOS+EXE significantly(P<0.05)increased milk yield,true protein and fat concentration,and energy-corrected milk yield(ECM)/DM intake,which could be reflected by the significant improvement(P<0.05)of dietary NDF and ADF digestibility.The results showed that dietary supplementation of XOS,EXE or XOS+EXE significantly(P<0.05)reduced CH_(4) emission,CH_(4)/milk yield,and CH_(4)/ECM.Furthermore,cows fed XOS demonstrated highest(P<0.05)metabolizable energy intake,milk energy output but lowest(P<0.05)of CH_(4) energy output and CH_(4) energy output as a proportion of gross energy intake compared with the remaining treatments.Conclusions Dietary supplementary of XOS,EXE or combination of XOS and EXE contributed to the improvement of lactation performance,nutrient digestibility,and energy utilization efficiency,as well as reduction of enteric CH_(4) emissions of lactating Jersey cows.This promising mitigation method may need further research to validate its long-term effect and mode of action for dairy cows.展开更多
Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 pub...Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha^(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha^(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.展开更多
China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency i...China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency is the basis of determining the idle and inefficient utilization courtyards in order to revitalizing it.This study provided a reference for the optimal use of rural courtyard utilization and revitalization through the quantitative comprehensive evaluation of courtyard utilization efficiency and the classification of courtyard utilization types.Taking Shandong Province in Eastern China as study area,we selected eight surveyed villages by stratified sampling method.According to the scale of the villages,full survey and sample survey were used,while middleaged men who familiar with the courtyards were selected as the respondents.Through a household questionnaire survey and face-to-face interviews from2017 to 2018,578 questionnaires of rural courtyardsin eight villages were obtained.Then based on the functions of rural courtyard and land resource conditions,16 comprehensive factors were formulated,involving land conditions,construction conditions and economic benefits,to build the comprehensive evaluation index system of rural courtyard utilization efficiency.Next the index weight was determined by analytic hierarchy process,and the linear weighted regression model was used to evaluate the utilization efficiency of rural courtyard.Finally,the K-means clustering analysis was used to classify the utilization efficiency of courtyards.The results showed that among the eight villages,the average utilization efficiency of courtyards was moderate(one village was low,five were moderate,and two were high).The proportions of both idle and inefficiently utilized courtyards were high.There were three vital factors leading to the idle and low efficiency of rural courtyards.They were declining rural industries,limited arable land per capita,and more farmer workers.In this case,the utilization efficiency of courtyards should be improved by transferring rural land,developing secondary and tertiary industries,evaluating the development potential of villages,classifying and optimizing courtyard utilization,so as to make full use of idle and inefficient courtyards,increase the income of farmers and collectives and promote the revitalization of rural areas.展开更多
Land spaces function in capacities of urban development,agricultural production,and ecological conservation,among many others.Research of land space utilization efficiency(LSUE)and coupling coordination relationships ...Land spaces function in capacities of urban development,agricultural production,and ecological conservation,among many others.Research of land space utilization efficiency(LSUE)and coupling coordination relationships among its subsystems are significant for sustainable land space development.In this study,taking the Urban Agglomeration in the Middle Reaches of the Yangtze River(UAMRYR)as the study area,we establish a measurement index system to evaluate the LSUE(2000–2018)and analyze its coupling coordination degree by utilizing an improved coupling coordination model.The main results include the following.(1)The average efficiency levels of urban space and agricultural space in the UAMRYR increased 2000–2018,while the average efficiency of ecological space declined.(2)The spatial pattern of the LSUE values varied greatly,with the distributions of high-efficiency and low-efficiency levels significantly different.(3)The coupling degree of LSUE includes three types,i.e.,high-level coupling,break-in,and antagonism.Each coupling degree type was characterized by change over time.(4)The proportion of areas with high coupling coordination and moderate coupling coordination increased from 2000 to 2018,while the proportion of areas with basic coupling coordination,moderate imbalance,and serious imbalance declined during this period.Given that the spatial differentiation of the LSUE and its coupling coordination,it is necessary to implement a differential land space development strategy in the UAMRYR.This study is helpful to promote the efficient utilization and coordinated development of land space utilization systems.展开更多
Improving the efficiency with which natural resources are utilized is an indispensable for achieving sustainable development and carbon neutrality. By analyzing the utilization efficiency of energy, water, and land, w...Improving the efficiency with which natural resources are utilized is an indispensable for achieving sustainable development and carbon neutrality. By analyzing the utilization efficiency of energy, water, and land, we established a comprehensive natural resource utilization efficiency index(NRUEI). We then calculated the 2016 index for 165 cities in China,and investigated what caused it to vary. We found three main results:(1) the NRUEI varied greatly across China and there were significant positive correlations between urban energy utilization efficiency(EUE), water utilization efficiency(WUE) and land utilization efficiency(LUE);(2) the NRUEI showed a significant positive correlation with a city’s population size,economy(Gross Domestic Product(GDP)), and the level of urban social development(GDP per capita);(3) cities in East China have the highest natural resource utilization efficiency,while cities in Northeast China have the lowest. These results indicate that China’s increasing urban development is associated with rising natural resource utilization efficiency and that the city’s endowment of natural resources is an important factor affecting that efficiency. Further, the results showed that the determinants of a city’s NRUEI differed in large and small cities. Lastly, our results suggest that improving EUE is key for improving NRUEI in urban China, and different efficiencies can be improved intertwined. A major takeaway of this study is that there is great potential for improving natural resource utilization efficiency in Chinese cities and we include city-specific suggestions for efficiency improvements.展开更多
基金Supported by the National Science and Technology Support Program(2009BADA8B01)Kunming Comprehensive Experimental Station,National Modern Agricultural Industrial Technology System of Rape(NYCYTX-00564)Yunnan Modern Agricultural Industrial Technology System Construction of Rape~~
文摘[Objective] This study aimed at investigating the effects of consumption of potassium fertilizer on production and biological characteristics of rape and utilizing efficiency of potassium fertilizer.[Method] Taking 0 kg/hm2 as control,nine consumptions of potassium fertilizer were designed for the experiment using single factor randomized block design with three replications and field experiment in nine rape-producing areas with different ecological types in Yunnan Province.[Result] Appropriately applying potassium fertilizer in Yunnan Province could improve the rapeseed production,the rape production could achieve 3 983-4 151 kg when applied 150-180 kg/hm2 of K2O,which had increased by 4.7-9.1% compared with the control and attained the peak in K165 treatment.When applied 1 kg of K2O,the rapeseed production could enhance 559 kg,the net profit could reach 1 229 yuan/hm2 and the partial productivity of potassium fertilizer could attain 31.32 kg/kg K2O and 3.7 kg/kg K2O,respectively.Applying potassium fertilizer could promote the growth of rape and increase rapeseed production.[Conclusion] The recommended optimal consumptions of potassium fertilizer with high production and high efficiency for rape in Yunnan Province were ranged between 150 and 180 kg K2O/hm2.However,comprehensively considering production and efficiency factors,the consumption of potassium fertilizer in Yunnan Province was around 73.9 kg/hm2,which should be appropriately increased to around 100.0 kg/hm2 in Longchuan,Yulong,Linxiang and other producing areas with similar conditions.
基金financially supported by the General Program of National Natural Science Foundation of China(No.52174330)Hunan Provincial Innovation Foundation for Postgraduate(No.QL20220069)Postgraduate Innovative Project of Central South University(No.1053320214756).
文摘The utilization of ironsand for preparing oxidized pellets poses challenges,including slow oxidation and low consolidation strength.The effects and function mechanisms of high-pressure grinding roll(HPGR)pretreatment on the oxidation and consolidation of ironsand pellets were investigated,and the energy utilization efficiency of HPGR with different roller pressure intensities was evaluated.The results indicate that HPGR pretreatment at 8 MPa improves the ironsand properties,with the specific surface area increasing by 740 cm^(2) g^(-1) and mechanical energy storage increasing by 2.5 kJ mol^(-1),which is conducive to oxidation and crystalline connection of particles.As roller pressure intensity increases to 16 MPa,more mechanical energy of HPGR is applied for crystal activation,with mechanical energy storage further rising by 18.1 kJ mol^(-1).The apparent activation energy for pellet oxidation initially decreases and then increases,reaching a minimum at 12 MPa.Simultaneously,the roasted pellets porosity decreases by 2.8%,while the compressive strength increases by 789 N.At higher roller pressure intensity,the densely connected structure between particles impedes gas diffusion within the pellets,diminishing the beneficial effects of HPGR on pellet oxidation.Moreover,excessive roller pressure intensity decreases the HPGR energy utilization efficiency.The optimal HPGR roller pressure intensity for ironsand is 12 MPa,at which the specific surface area increases by 790 cm^(2) g^(-1),mechanical energy storage increases by 10.6 kJ mol^(-1),the compressive strength of roasted pellets rises to 2816 N,and the appropriate preheating and roasting temperatures decrease by 250 and 125°C,respectively.
基金financially supported by the National Natural Science Foundation of China(21905137)the Research Grants Council of Hong Kong(15307922,C5037-18G,C4005-22Y)+1 种基金RGC Senior Research Fellowship Scheme(SRFS2223-5S01)the Hong Kong Polytechnic University:Sir Sze-yuen Chung Endowed Professorship Fund(8-8480)。
文摘Semitransparent organic photovoltaics(ST-OPVs)for building integration represent a pivotal direction in the development of photovoltaic industry.Solution-processed silver nanowires(AgNWs)are considered promising candidates for transparent electrodes in semitransparent devices due to their high transparency-conductivity-efficiency merit,large-scale processability,and low cost.In this work,we develop two solution-processed organic–inorganic hybrid electrodes,named AgNWs-PD and AgNWsPC,utilizing AgNWs as the conductive framework and aliphatic amine-functionalized perylene-diimide(PDINN)as the sandwiched material,while AgNWs-PC exhibits significantly improved electrical conductivity and enhanced contact area with the underlying electron transport layer.The optimized device achieves a power conversion efficiency of 9.45%with an open circuit voltage of 0.846 V,a high filling factor of 75.4%,and an average visible transmittance(AVT)of 44.0%,delivering an outstanding light utilization efficiency(LUE)of 4.16%,which is the highest reported value for all solution-processed ST-OPVs.In addition,by coupling a 30-nm tellurium dioxide atop AgNWs-PC,the bifaciality factor of derivative devices improves from 73.7%to 99.4%,while maintaining a high bifacial LUE over 3.7%.Our results emphasize the superiority and effectiveness of PDINN-sandwiched AgNWs electrodes for highperformance and all solution-processed ST-OPVs.
基金supported by the National Key Research and Development Program of China (2021YFD1901200)the Key Research and Development Program of Hubei Province of China (2023BBB028)+1 种基金the Earmarked Fund of Hubei province of Chinathe Fundamental Research Funds for the Central Universities (2662024ZKQD005)
文摘The effects of micro-ridge-furrow planting(MR)on yield and the efficiency of light,water,and thermal resource use in rapeseed were tested in a three-year field experiment comparing MR to conventional flat planting.MR enhanced canopy heterogeneity by altering the leaf angle between plants on ridges and furrows.The heterogeneous canopy environment increased intercepted photosynthetic active radiation,alleviated canopy temperature stress,and optimized canopy humidity,leading to improvements in light-nitrogen matching and net photosynthetic rate.Consequently,dry matter and yield increased by 13.0%and 11.0%,respectively,while radiation,thermal,and precipitation utilization efficiency increased by 12.3%-16.2%.The corresponding improvements in yield and resource use efficiency were attributed to a heterogeneous canopy environment that improved microclimatic conditions.
基金supported by the National Key Research and Development Program of China(2024YFD2301200)National Nature Science Foundation of China(32172662).
文摘With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared at the seedling stage.P-efficient cultivars showed root morphological adaptation,high P uptake activity,and greater phospholipid degradation under low P stress.Improving root morphological adaptation and reducing lipid-P allocation could allow increasing PUE in rapeseed seedlings.
基金supported by the the Guizhou Provincial Excellent Young Talents Project of Science and Technology,China(YQK(2023)002)the Guizhou Provincial Science and Technology Projects,China((2022)Key 008)+2 种基金the Guizhou Provincial Science and Technology Support Plan,China((2022)Key 026)the Key Laboratory of Molecular Breeding for Grain and Oil Crops in Guizhou Province,China((2023)008)the Key Laboratory of Functional Agriculture of Guizhou Provincial Higher Education Institutions,China((2023)007)。
文摘Low-affinity nitrate transporter genes have been identified in subfamilies 4-8 of the rice nitrate transporter 1(NRT1)/peptide transporter family(NPF),but the OsNPF3 subfamily responsible for nitrate and phytohormone transport and rice growth and development remains unknown.In this study,we described OsNPF3.1 as an essential nitrate and phytohormone transporter gene for rice tillering and nitrogen utilization efficiency(NUtE).OsNPF3.1 possesses four major haplotypes of its promoter sequence in 517 cultivars,and its expression is positively associated with tiller number.Its expression was higher in the basal part,culm,and leaf blade than in other parts of the plant,and was strongly induced by nitrate,abscisic acid(ABA)and gibberellin 3(GA_3)in the root and shoot of rice.Electrophysiological experiments demonstrated that OsNPF3.1 is a pH-dependent low-affinity nitrate transporter,with rice protoplast uptake assays showing it to be an ABA and GA_3 transporter.OsNPF3.1 overexpression significantly promoted ABA accumulation in the roots and GA accumulation in the basal part of the plant which inhibited axillary bud outgrowth and rice tillering,especially at high nitrate concentrations.The NUtE of OsNPF3.1-overexpressing plants was enhanced under low and medium nitrate concentrations,whereas the NUtE of OsNPF3.1 clustered regularly interspaced short palindromic repeats(CRISPR)plants was increased under high nitrate concentrations.The results indicate that OsNPF3.1 transports nitrate and phytohormones in different rice tissues under different nitrate concentrations.The altered OsNPF3.1 expression improves NUtE in the OsNPF3.1-overexpressing and CRISPR lines at low and high nitrate concentrations,respectively.
基金Supported by National Key Technology R&D Program of China(2007BAD88B06)~~
文摘[Objective] This study was to investigate the effects of different irrigation amount on water consumption and water use efficiency of greenhouse cucumber.[Method]Under the condition of drip irrigation with different water amounts in sunlight greenhouse of the arid areas in Ningxia,the soil water was measured and the water consumption of crop was calculated.[Result]When irrigation amount was 563 mm,the water consumption as a whole gradually increased with the delay of growth period,reached peak during the thriving stage of fruit setting,and then gradually declined;in each treatment,the daily water consumption increased with the increasing of irrigation amount during each growth period.However,the consumption of soil moisture reduced with the significant increase of irrigation.563 mm of irrigation amount could meet the water requirements of cucumber and began to add water to soil,and water utilization efficiency could reach 33.4 kg/m3.[Conclusion]The research had provided theoretical basis for water management in the production process of greenhouse cucumber.
基金Supported by Construction of Southwestern Rice Innovation System,Science and Technology Project on Food Production (2006BAD02-A05)Agriculture Science Technology Achievement TransformationFund (2006GB2F000256)+2 种基金Sichuan Provincial Foundation for Lead-ers of Disciplines in ScienceProject of Rice Breeding Technology ofSichuanProgram Promoted by Sichuan Financial Administration~~
文摘[Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and utilization efficiency for mid-season hybrid rice.[Method] By using mid-season rice varieties II-you 7 and Yuxiangyou203 as the experimental materials,field experiment was conducted at seven ecological sites in four provinces or cities in Southwestern China in 2009.A total of four nitrogen application levels were set as follows：by using 75 kg/hm2 of P2O5 and 75 kg/hm2 of K2O as the base fertilizer,extra 0,90,150 and 210 kg/hm2 of nitrogen fertilizer（in which,base fertilizer,base-tillering fertilizer and base-earing fertilizer respectively accounted for 60%,20% and 20%.） was applied,respectively.In the split-plot design,fertilizer was considered as the main factor while rice variety was taken as the secondary factor.A total of eight treatments were set with three replications.[Result] Highly significant differences of grain yield were found among seven locations,two varieties,four nitrogen application levels,interactions of site × variety and site × nitrogen application level,but the interaction of variety ×nitrogen application level had no significant influence on rice yield.There were highly significant effects of site,varieties and nitrogen application level on dry matter production,nitrogen content,nitrogen utilization efficiency.Highly significant negative correlations between uptake efficiency and utilization efficiency for nitrogen were found;and multiple stepwise regression analysis showed that nitrogen uptake-utilization efficiency were significantly influenced by different ecological sites,chemical quality of soil and the levels of nitrogen application.[Conclusion] The research will provide theoretical and practical basis for the highly efficient application of nitrogen in mid-season hybrid rice cultivation.
文摘Against the backdrop of active global responses to climate change and the accelerated green and low-carbon energy transition,the co-optimization and innovative mechanism design of multimodal energy systems have become a significant instrument for propelling the energy revolution and ensuring energy security.Under increasingly stringent carbon emission constraints,how to achieve multi-dimensional improvements in energy utilization efficiency,renewable energy accommodation levels,and system economics-through the intelligent coupling of diverse energy carriers such as electricity,heat,natural gas,and hydrogen,and the effective application of market-based instruments like carbon trading and demand response-constitutes a critical scientific and engineering challenge demanding urgent solutions.
基金supported by the National Key Research and Development Program of China(2022YFE0208400)the Shanxi Province Key Research and Development Program Project(202202090301002).
文摘A lab-scale adiabatic reactor has been self-made to characterize the coupled properties of heat and reactions during the co-thermal-processing of coal and biomass with steam or steam/O_(2) gasification agents.Results showed that the synergistic effects caused by heat transfer between corncob and coal at different mixing ratios were heavily determined by coal rank and gasification agent.During steam co-processing,the heat transfer from corncob char to adjacent bituminous coal char promoted the water-gas reaction on coal char and contributed to synergistic effects;the heat transfer from anthracite char to adjacent corncob char reduced the kinetic rate of the water-gas reaction on coal char and contributed to inhibitory effects,and the inhibitory effect caused by heat transfer was greater than the promotion effects of biomass mass transfer.The introduction of O_(2) diminished the impact of inter-particle heat transfer and altered the intensity of synergy,decreasing the values of synergy factor of bituminous coal/corncob blends by 17%and increasing the value of synergy factor of anthracite/corncob blends by 142.5%.This study provides sufficient support for the process conditions selection for the production of syngas with specific H_(2)/CO molar ratios and the desired level of gasification performance.
基金supported by the National Natural Science Foundation of China(32160503)the Earmarked Fund for Jiangxi Agriculture Research System,China(JXARS-01)the National Key R&D Program of China(2023YFD2301303).
文摘Straw return has demonstrated significant potential for enhancing carbon(C)sequestration and nitrogen(N)uptake while concurrently promoting plant productivity.However,the specific transport and distribution of C produced by photosynthesis and exogenous N within the rice plant-soil system under straw return remains unclear.A long-term straw return pot trial experiment was conducted in a double cropping rice system,incorporating treatments of inorganic fertilizer application with straw removal(F),straw burning and ash return with reducing inorganic fertilizers(SBR),and straw return with reducing inorganic fertilizers(SR)to investigate C sequestration and exogenous N uptake using ^(13)C pulse and ^(15)N isotope tracer techniques.The SR treatment had significantly higher soil ^(13)C abundance,by 24.4 and 25.4%,respectively,^(13)C concentrations in aboveground plant parts,by 18.4 and 35.8%respectively,and ^(15)N concentrations in rice panicles,by 12.8 and 34.3%than the SBR and F treatments.This enhancement contributed to a higher total organic C concentration and increased rice grain yield in the SR treatment.Furthermore,the SR treatment had significantly higher photosynthetic C,by 9.8%,which was directly transferred to soil C.The SR treatment had a higher distribution of photosynthetic C in the leaves and stems,but a lower distribution in the panicle compared to the SBR treatment.This finding is advantageous for sequestering photosynthetic C into the soil through straw return;conversely,opposite trends were observed in ^(15)N distribution.In addition,rice plants in the SR treatment had increased N uptake from urea and soil N sources,enhancing N recovery by 9.2 and 12.5%,respectively,and reducing soil N residues.Correlation analysis showed that the SR treatment increased the concentrations of ^(13)C in leaves and roots while decreasing the ^(15)N abundance in all rice organs,thereby contributing to an increase in rice yield.The partial least square path model suggested that the increase in rice yield under the SR treatment was primarily linked to ^(13)C accumulation within the rice plant-soil system.The results suggest that straw return increases the sequestration of photosynthetic C and exogenous N in the rice plant-soil system and increases N utilization efficiency,which subsequently improves both rice and soil productivity.
基金Project supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX2-413-3)National Natural Science Foundation of China (No.30390080)National Basic Research Program of China (No.2005CB121108)
文摘Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.
基金National Social Science Foundation of China, No. 11BJY063 Program for New Century Excellent Talents in University, No.NECT-13-0844
文摘Based on provincial panel data of water footprint and grey water footprint, and with the help of data envelopment analysis model considering and without considering the unde- sirable output, this paper estimates the water resources utilization efficiency in China from 1997 to 2011. The spatial weighting matrix based on economy-spatial distance function is established to discuss spatial autocorrelation of water resources utilization efficiency. With the help of absolute/3-convergence model, this paper concludes that there exists/%convergence in the water resources utilization efficiency. Under the conditions of considering and without considering the undesirable output, it takes about 52.6 and 5.6 years respectively to achieve the extent of half of convergence. By mean of the spatial Durbin econometric model, this paper studies spatial spillover effects of the provincial water resources utilization efficiency in China. The results are as follows. 1） With considering and without considering the undesir- able output, there is significant spatial correlation in provincial water resource efficiency in China. 2） Under the two cases, the spatial autoregressive coefficients （p） are 0.278 and 0.507 respectively, at 1% significance level. There exist the spatial spillover effects of provin- cial water resources utilization efficiency. 3） With considering the undesirable output, these factors of the education funds, the transportation infrastructure, and the industrial and agri- cultural water consumption proportion have positive impacts. These factors of foreign direct investment, the industry value-added water consumption per ten thousand yuan, per capita water consumption, and the total precipitation have negative impacts. 4） Without considering the undesirable output, the factor of GDP per laborer has a greater positive significant influ- ence on the water resources utilization efficiency. However the facts of industry value-added water consumption in ten thousand yuan and the transportation infrastructure have no sig- nificant influence. 5） Regardless of undesirable output of water resources utilization efficiency the assessment of the present real water resources utilization in China will be distorted and policy-making will be misled. The water efficiency measure considering environmental factors （such as gray water footprint） is more reasonable.
基金Key Research Program of Chinese Academy of Sciences(No.KZZD-EW-06-03-03)
文摘The efficient use of water resources directly affects environmental, social, and economic development; therefore, it has a significant impact on urban populations. A slacks-based measure for data envelopment analysis （SBM-DEA） has been widely used in energy efficiency and environmental efficiency analyses in recent years. Based on this model, data from 316 cities were examined and a category method was employed involving three different sorting techniques to empirically evaluate the efficiency of urban water re- source utilization in China between 2000 and 2012. The overall efficiency （OE） of urban water resource utilization in China was initially low, but has improved over the past decade. The scale efficiency （SE） was higher than the pure technological efficiency （PTE）; PTE is a major determining factor of OE, and has had an increasingly significant effect. The efficiency of water resource utilization varied ac- cording to the region, urban scale, and economic function. The OE score for the eastern China was higher than for the rest of the region, and the OE score for the western China was higher than for the central China. The OE score for urban water resource utilization has improved with urban expansion, except in the case of small cities. The SE showed an inverted U-shaped＇ trend with increasing urban expansion. The OE of urban water utilization in comprehensive functional cities was greater than in economic specialization cities, and was greater in heavy industry specialization cities than in other specialization cities. This study contributes to the field of urban water resource management by examining variations in efficiency with urban ~ezle
基金supported by the National High-Tech Research&Development program(Grant No.2003AA206030)the National Natural Science Foundation of China(Grant No.30030090)
文摘In order to establish methods for indentification and screening of rice genotypes with high nitrogen （N） efficiency, N absorption efficiency （NAE）, N utilization efficiency （NUE） and N harvest index （NHI） in ten rice genotypes were investgated at the elongation, booting, heading and maturity stages under six N levels in a pot experiment with soil-sand mixtures at various ratios. NAE in various rice genotypes firstly increased, peaked under a medium nitrogen rate of 0.177 g/kg and then decreased, but NUE and NHI always decreased with increasing nitrogen levels. NAE in various rice genotypes ever increased with growing process and NUE indicated a descending tendency of elongation stage〉heading stage〉maturity stage〉booting stage. N level influenced rice NAE, NUE and NHI most, followed by genotype, and the both effects were significant at 0.01 level. In addition, the interaction effects of genotype and nitrogen level on rice NAE and NUE were significant at 0.01 level, but not significant on rice NHI. Because the maximum differences of NAE and NUE were found at the elongation stage, it was thought to be the most suitable stage for identification and screening these two paremeters. Therefore, the optimum conditions for identification and screening of rice NAE, NUE and NHI in a pot experiment were the nitrogen rate of 0.157 g/kg at the elongation stage, low nitrogen at the elongation stage, and the nitrogen rate of 0.277 g/kg at the maturity stage, respectively.
基金the Key Program for International S&T Cooperation Projects of China(2022YFE0130100)Central Public-interest Scientific Institution Basal Research Fund of Chinese Academy of Agricultural Sciences(Y2022GH12).
文摘Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to investigate the effects of dietary xylooligosaccharides(XOS)and exogenous enzyme(EXE)supplementation on milk production,nutrient digestibility,enteric CH_(4) emissions,energy utilization efficiency of lactating Jersey dairy cows.Forty-eight lactating cows were randomly assigned to one of 4 treatments:(1)control diet(CON),(2)CON with 25 g/d XOS(XOS),(3)CON with 15 g/d EXE(EXE),and(4)CON with 25 g/d XOS and 15 g/d EXE(XOS+EXE).The 60-d experimental period consisted of a 14-d adaptation period and a 46-d sampling period.The enteric CO_(2)and CH_(4) emissions and O2 consumption were measured using two GreenFeed units,which were further used to determine the energy utilization efficiency of cows.Results Compared with CON,cows fed XOS,EXE or XOS+EXE significantly(P<0.05)increased milk yield,true protein and fat concentration,and energy-corrected milk yield(ECM)/DM intake,which could be reflected by the significant improvement(P<0.05)of dietary NDF and ADF digestibility.The results showed that dietary supplementation of XOS,EXE or XOS+EXE significantly(P<0.05)reduced CH_(4) emission,CH_(4)/milk yield,and CH_(4)/ECM.Furthermore,cows fed XOS demonstrated highest(P<0.05)metabolizable energy intake,milk energy output but lowest(P<0.05)of CH_(4) energy output and CH_(4) energy output as a proportion of gross energy intake compared with the remaining treatments.Conclusions Dietary supplementary of XOS,EXE or combination of XOS and EXE contributed to the improvement of lactation performance,nutrient digestibility,and energy utilization efficiency,as well as reduction of enteric CH_(4) emissions of lactating Jersey cows.This promising mitigation method may need further research to validate its long-term effect and mode of action for dairy cows.
基金supported by the National Key Research and Development Program of China(2016YFD0300100)the Innovation Program of Chinese Academy of Agricultural Sciencesthe Elite Youth Program of the Chinese Academy of Agricultural Science。
文摘Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha^(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha^(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.
文摘China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency is the basis of determining the idle and inefficient utilization courtyards in order to revitalizing it.This study provided a reference for the optimal use of rural courtyard utilization and revitalization through the quantitative comprehensive evaluation of courtyard utilization efficiency and the classification of courtyard utilization types.Taking Shandong Province in Eastern China as study area,we selected eight surveyed villages by stratified sampling method.According to the scale of the villages,full survey and sample survey were used,while middleaged men who familiar with the courtyards were selected as the respondents.Through a household questionnaire survey and face-to-face interviews from2017 to 2018,578 questionnaires of rural courtyardsin eight villages were obtained.Then based on the functions of rural courtyard and land resource conditions,16 comprehensive factors were formulated,involving land conditions,construction conditions and economic benefits,to build the comprehensive evaluation index system of rural courtyard utilization efficiency.Next the index weight was determined by analytic hierarchy process,and the linear weighted regression model was used to evaluate the utilization efficiency of rural courtyard.Finally,the K-means clustering analysis was used to classify the utilization efficiency of courtyards.The results showed that among the eight villages,the average utilization efficiency of courtyards was moderate(one village was low,five were moderate,and two were high).The proportions of both idle and inefficiently utilized courtyards were high.There were three vital factors leading to the idle and low efficiency of rural courtyards.They were declining rural industries,limited arable land per capita,and more farmer workers.In this case,the utilization efficiency of courtyards should be improved by transferring rural land,developing secondary and tertiary industries,evaluating the development potential of villages,classifying and optimizing courtyard utilization,so as to make full use of idle and inefficient courtyards,increase the income of farmers and collectives and promote the revitalization of rural areas.
基金National Natural Science Foundation of China,No.42171249,No.42201270National Social Science Foundation of China,No.20BJY119Jiangsu Social Science Foundation,No.18GLC016。
文摘Land spaces function in capacities of urban development,agricultural production,and ecological conservation,among many others.Research of land space utilization efficiency(LSUE)and coupling coordination relationships among its subsystems are significant for sustainable land space development.In this study,taking the Urban Agglomeration in the Middle Reaches of the Yangtze River(UAMRYR)as the study area,we establish a measurement index system to evaluate the LSUE(2000–2018)and analyze its coupling coordination degree by utilizing an improved coupling coordination model.The main results include the following.(1)The average efficiency levels of urban space and agricultural space in the UAMRYR increased 2000–2018,while the average efficiency of ecological space declined.(2)The spatial pattern of the LSUE values varied greatly,with the distributions of high-efficiency and low-efficiency levels significantly different.(3)The coupling degree of LSUE includes three types,i.e.,high-level coupling,break-in,and antagonism.Each coupling degree type was characterized by change over time.(4)The proportion of areas with high coupling coordination and moderate coupling coordination increased from 2000 to 2018,while the proportion of areas with basic coupling coordination,moderate imbalance,and serious imbalance declined during this period.Given that the spatial differentiation of the LSUE and its coupling coordination,it is necessary to implement a differential land space development strategy in the UAMRYR.This study is helpful to promote the efficient utilization and coordinated development of land space utilization systems.
基金supported by the National Natural Science Foundation of China (Nos. 42101290 and 71533005)the Special Project on National Science and Technology Basic Resources Investigation of China (No. 2021FY100703)。
文摘Improving the efficiency with which natural resources are utilized is an indispensable for achieving sustainable development and carbon neutrality. By analyzing the utilization efficiency of energy, water, and land, we established a comprehensive natural resource utilization efficiency index(NRUEI). We then calculated the 2016 index for 165 cities in China,and investigated what caused it to vary. We found three main results:(1) the NRUEI varied greatly across China and there were significant positive correlations between urban energy utilization efficiency(EUE), water utilization efficiency(WUE) and land utilization efficiency(LUE);(2) the NRUEI showed a significant positive correlation with a city’s population size,economy(Gross Domestic Product(GDP)), and the level of urban social development(GDP per capita);(3) cities in East China have the highest natural resource utilization efficiency,while cities in Northeast China have the lowest. These results indicate that China’s increasing urban development is associated with rising natural resource utilization efficiency and that the city’s endowment of natural resources is an important factor affecting that efficiency. Further, the results showed that the determinants of a city’s NRUEI differed in large and small cities. Lastly, our results suggest that improving EUE is key for improving NRUEI in urban China, and different efficiencies can be improved intertwined. A major takeaway of this study is that there is great potential for improving natural resource utilization efficiency in Chinese cities and we include city-specific suggestions for efficiency improvements.
