Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in t...Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.展开更多
Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)...Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)and future climate change scenarios(different Representative Concentration Pathways(RCPs)in different future time periods)are among the major sources of uncertainty in projecting the impact of climate change on crop grain yield.This study quantified the different sources of uncertainty associated with future climate change impact on wheat grain yield in dryland environments(Shiraz,Hamedan,Sanandaj,Kermanshah and Khorramabad)in eastern and southern Iran.These five representative locations can be categorized into three climate classes:arid cold(Shiraz),semi-arid cold(Hamedan and Sanandaj)and semi-arid cool(Kermanshah and Khorramabad).Accordingly,the downscaled daily outputs of 29 GCMs under two RCPs(RCP4.5 and RCP8.5)in the near future(2030s),middle future(2050s)and far future(2080s)were used as inputs for the Agricultural Production Systems sIMulator(APSIM)-wheat model.Analysis of variance(ANOVA)was employed to quantify the sources of uncertainty in projecting the impact of climate change on wheat grain yield.Years from 1980 to 2009 were regarded as the baseline period.The projection results indicated that wheat grain yield was expected to increase by 12.30%,17.10%,and 17.70%in the near future(2030s),middle future(2050s)and far future(2080s),respectively.The increases differed under different RCPs in different future time periods,ranging from 11.70%(under RCP4.5 in the 2030s)to 20.20%(under RCP8.5 in the 2080s)by averaging all GCMs and locations,implying that future wheat grain yield depended largely upon the rising CO2 concentrations.ANOVA results revealed that more than 97.22% of the variance in future wheat grain yield was explained by locations,followed by scenarios,GCMs,and their interactions.Specifically,at the semi-arid climate locations(Hamedan,Sanandaj,Kermanshah and Khorramabad),most of the variations arose from the scenarios(77.25%),while at the arid climate location(Shiraz),GCMs(54.00%)accounted for the greatest variation.Overall,the ensemble use of a wide range of GCMs should be given priority to narrow the uncertainty when projecting wheat grain yield under changing climate conditions,particularly in dryland environments characterized by large fluctuations in rainfall and temperature.Moreover,the current research suggested some GCMs(e.g.,the IPSL-CM5B-LR,CCSM4,and BNU-ESM)that made moderate effects in projecting the impact of climate change on wheat grain yield to be used to project future climate conditions in similar environments worldwide.展开更多
Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah regi...Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.展开更多
China is a large agricultural and the most populous country, so it is a crucial importance for the food security. The basic situation of food in our country is self-sufficiency, a certain amount of imports and reserve...China is a large agricultural and the most populous country, so it is a crucial importance for the food security. The basic situation of food in our country is self-sufficiency, a certain amount of imports and reserves. The output of grain in our country has increased annually, however, as a result of policy adjustments and other factors like environmental pollution, together with a large population base and the trend of excessively popu- lous growth, the growth of grain output is relatively slow, which will be harmful for our grain security as well as the healthy development of the na- tional economy. In this case, several solutions could be tried, such as improving the level of science and technology, adjusting industrial policies and controlling environmental pollution. Besides, we ought to strongly advocate thrifty behavior to increase income and reduce expenditure.展开更多
Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and...Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB.展开更多
Through an in-depth analysis of the per capita net income of rural residents in Nyingchi City,it was known that the per capita net income of rural residents in Nyingchi City was increasing at high speed in recent 10 y...Through an in-depth analysis of the per capita net income of rural residents in Nyingchi City,it was known that the per capita net income of rural residents in Nyingchi City was increasing at high speed in recent 10 years. However,the wage income,household operating income,and agricultural income gap constitute the major factors influencing the gap of the per capita net income of rural residents in Nyingchi City. Finally,it came up with recommendations including promoting the reasonable flow of labor to the secondary and tertiary industries,increasing the wage income and transfer income of rural residents,accelerating the construction of small towns in rural areas,promoting the development of rural cooperatives,implementing the strategy of " benefiting farmers and strengthening tourism",promoting integration of agriculture and eco-tourism,promoting the development of modern agriculture,and expanding diversified production income of farmers.展开更多
Adopting Just and Pope (1978, 1979) style yield functions, this paper proposes a method to analyze the impacts of regional climate change on grain production in China. We find that changes in climate will affect gra...Adopting Just and Pope (1978, 1979) style yield functions, this paper proposes a method to analyze the impacts of regional climate change on grain production in China. We find that changes in climate will affect grain production in North and South China differently. Specifically, it emerges that a 1℃ increase in annual average temperature could reduce national grain output by 1.45% (1.74% reduction in North China and 1.19% reduction in South China), while an increase in total annual precipitation of around 100 mm could increase national grain output by 1.31% (3.0% increase in North China and 0.59% reduction in South China).展开更多
To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp, indica var. Mottaikaruppan) and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfa...To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp, indica var. Mottaikaruppan) and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate (SDS) (1.0 g/L) and Triton-X-100 (1.0 mL/L)], whole rice grains soaked in distilled water for 12 h at 30℃were germinated in the dark at 30℃ for five days. The highest germination rate (77.1%) was obtained on the 5th day. An increase in the content of reducing sugars from 7.3 to 58.1 mg/g DM (dry matter) was observed from the 1st day of germination. Free amino acids and soluble protein contents increased to 3.69 and 5.29 mg/g DM, respectively on the 5^th day of germination. Total protein content decreased from 100.5 to 91.0 g/kg DM during germination. Increases in amylolytic (1.1 to 190.0 U/g DM) and proteolytic (0 to 0.12 U/g DM) activities were observed during germination. Effects of different concentrations of gibberellic acid on the germination of rice grains were evaluated and 0.1 g/L was found to promote germination. When effects of gibberellic acid (0.1 g/L) and surfactants were evaluated individually and together, higher germination rate was observed in the control experiment (grains germinated in distilled water), whereas giberellic acid and surfactants decreased the germination rate. Therefore, the flour obtained from the grains germinated for four days using distilled water to obtain high content of soluble materials and enzyme activities can be used in preparation of bakery items.展开更多
Using a logistic model,this paper empirically investigated farmers’perception of climate change and its determinants based on a field survey of 1 350 rural households across five major grain producing provinces in Ch...Using a logistic model,this paper empirically investigated farmers’perception of climate change and its determinants based on a field survey of 1 350 rural households across five major grain producing provinces in China.The results show:i)There is an apparent difference in perception levels for long-term temperature and precipitation changes.Specifically,57.4%of farmers perceived the long-term temperature change correctly,but only 29.7%of farmers perceived the long-term precipitation change correctly;ii)The factors influencing the farmers’perceptions are almost completely different between precipitation and temperature,the former are mostly agriculture related,while latter are mostly non-agriculture related,except for farm size;and iii)Farmers are not expected to pay more attention to long-term precipitation changes over the crop growing seasons,because less than 30%of farmers can correctly perceive long-term precipitation change.Therefore,to improve the accuracy of farmers’perceptions of climate change,the government is recommended to:i)enhance education and training programs;ii)speed up land transfer and expand household land farm size;iii)develop farmer cooperative organizations;iv)invest more in agricultural infrastructure,specifically in major grain producing regions;and v)improve the agricultural environment and increase farming income.展开更多
The changes in utilization of agricultural land have gradually grown into one of the major factors impacting grain output in China. This study explores the various components of agricultural production in China from t...The changes in utilization of agricultural land have gradually grown into one of the major factors impacting grain output in China. This study explores the various components of agricultural production in China from the land utilization perspective, involving changes in grain production per unit area, multi-cropping index, and adjustment of agricultural structure. Compared with the record values, different research methodologies are used to analyze the po- tential of above three components. The results indicate that grain production potential of 65.68×109kg was unexploited in 2006, in which 45.8×109kg came from the restructuring in agriculture. So we can infer that the reduction of grain production in China could be primarily attributed to agricultural restructuring in recent years. So the productive poten- tial can be fully restored by increasing agricultural investment, or recovering agricultural structure in favorable condi- tions. So we can say that China’s current condition of food security is good.展开更多
China's grain production cost has risen constantly since 2003. This paper starts from the grain production cost changes of unit area and unit quality,to analyze the reasons for China's grain production cost ch...China's grain production cost has risen constantly since 2003. This paper starts from the grain production cost changes of unit area and unit quality,to analyze the reasons for China's grain production cost change in the last decade. It points out that the direct cause of changes in grain production cost is the steady growth of material and services costs,the fastest growth of labor costs and fast growth of land costs. The indirect cause of grain production high cost is the low efficiency in numerous and dispersive farmer production management,obviously insufficient agricultural infrastructure construction,waste phenomenon grain in production process and low contribution rate of agricultural technology.On this basis,it is recommended to reduce China's grain production cost and improve grain production conditions.展开更多
In a recent paper [2002 Phys. Rev. Lett. 88 174102], Bandt and Pompe propose permutation entropy (PE) as a natural complexity measure for arbitrary time series which may be stationary or nonstationary,deterministic ...In a recent paper [2002 Phys. Rev. Lett. 88 174102], Bandt and Pompe propose permutation entropy (PE) as a natural complexity measure for arbitrary time series which may be stationary or nonstationary,deterministic or stochastic.Their method is based on a comparison of neighbouring values.This paper further develops PE,and proposes the concept of fine-grained PE (FGPE) defined by the order pattern and magnitude of the difference between neighbouring values. This measure excludes the case where vectors with a distinct appearance are mistakenly mapped onto the same permutation type,and consequently FGPE becomes more sensitive to the dynamical change of time series than does PE,according to our simulation and experimental results.展开更多
Analysis of recent changes in the amount and nature of cultivated land and grain potential, and the impacts of these changes on grain security in China's Mainland provides vital information for revising and develo...Analysis of recent changes in the amount and nature of cultivated land and grain potential, and the impacts of these changes on grain security in China's Mainland provides vital information for revising and developing strategies regarding protection of cultivated land and national grain security. This study examined changes in the area of cultivated land and in grain potential in agro-ecological zones using the "change rate" method. Agro-ecological subzones were used as the basic units and agro-ecological zones as the research units. We then studied changes for all of China's Mainland using the "gravity centre model" and analyzed the structural change of cultivated lands in each agro-ecological zone to investigate the changes in detail. The results show that both cultivated land and grain potential in China's Mainland decreased from 1996 to 2007. The structural and quantitative changes in each zone have caused the shift of the gravity centres of cultivated land and grain potential in China's Mainland to the northeast. Unfortunately, it is unlikely that natural and economic resources can keep up with this change. Although a large gap remains between the grain potential and the actual grain yield, the rapid loss of grain potential and the direction of change pose great threats to grain security. To ensure comprehensive grain security in China, it is vital to rethink the regional patterns of grain production according to natural conditions without jeopardising cultivated land protection(quantitative and qualitative), and consider the direction of cultivated land use and reconstruction according to local natural conditions, water and soil resources, and the level of economic development, and then work steadily to improve the grain potential.展开更多
To scientifically respond to the impact of climate change on winter wheat production,spike-grain structure data of winter wheat at Jiangsu Phenometeorological Observatory were taken as the sample. Based on agrometeoro...To scientifically respond to the impact of climate change on winter wheat production,spike-grain structure data of winter wheat at Jiangsu Phenometeorological Observatory were taken as the sample. Based on agrometeorology,statistics and GIS analytical technique,status quo of spike-grain structure of winter wheat in Jiangsu and its climate change tendency were analyzed systemically. The results showed that climate change rate( CTR) of mature spike number( NS) was between-53. 37 and 256. 51 spikes/( m^2·10 a),and mean of whole province was 21.45 spikes/( m^2·10 a). CTR of number of grains per panicle( GNPS) was between-0. 58 and 12. 52 grains/( spike·10 a),and mean of whole province was 2. 39 grains/( spike·10 a). CTR of thousand-grain weight( TSW) was between-1. 65 and 16. 39 g/( 1 000 grains·10 a),and mean of whole province was 2. 86 g/( 1 000 grains·10 a). For the means of NS,GNPS,and TSW in whole province,they all showed the increasing trend with climate change,and they were just unbalanced among regions. Climate change induced the variation of meteorological conditions during growth period of winter wheat in Jiangsu. The variation of unity yield( UY) caused by this kind of change trend only accounted for-4. 32%-17. 23% of that in normal climate years,and mean of whole province was 6. 4%. That is to say,comprehensive impact of meteorological condition was favorable for improving the yield of winter wheat with climate change. Therefore,coordination level of winter wheat growth and real-time meteorological conditions could be regulated by breeding the varieties with wide climate suitability,regulating sowing date and density according to local production and management level,rational fertilization and applying growth regulator,to mitigate the adverse effects of climate change on winter wheat production,and reach high yield and quality.展开更多
Mu Us Sandy Land(MUSL) of China, as a typical eco-fragile and farming-pastoral transitional region, shows great vulnerability to disturbances from cultivation activity. In this region, the conflict between cultivation...Mu Us Sandy Land(MUSL) of China, as a typical eco-fragile and farming-pastoral transitional region, shows great vulnerability to disturbances from cultivation activity. In this region, the conflict between cultivation activity and environmental protection has not attracted great importance until the implementation of China's Grain-for-Green Policy(CGGP) since2000. Here, using Landsat5 TM/Landsat7 ETM+ images from 1990, 2000, and 2010, we monitor the cultivation activity and land-use/cover changes(LUCC) resulting from cultivation activity in the MUSL region. Based on the data from images, we developed a series of databases of cultivated activity-induced LUCC and use them to discuss comparatively the spatio-temporal evolution trends of cultivation activity before and after CGGP implementation. These results provide evidence for managers to evaluate the implementation effectiveness of governmental policy and the influence of cultivation activity on the ecological environment of the MUSL region.展开更多
基金supported by National Natural Science Foundation of China (52070194,52073309)Natural Science Foundation of Hunan Province (2022JJ20069)。
文摘Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.
基金funded by the Deputy of Research Affairs, Lorestan University, Iran (Contract No. 1400-6-02-518-1402)
文摘Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)and future climate change scenarios(different Representative Concentration Pathways(RCPs)in different future time periods)are among the major sources of uncertainty in projecting the impact of climate change on crop grain yield.This study quantified the different sources of uncertainty associated with future climate change impact on wheat grain yield in dryland environments(Shiraz,Hamedan,Sanandaj,Kermanshah and Khorramabad)in eastern and southern Iran.These five representative locations can be categorized into three climate classes:arid cold(Shiraz),semi-arid cold(Hamedan and Sanandaj)and semi-arid cool(Kermanshah and Khorramabad).Accordingly,the downscaled daily outputs of 29 GCMs under two RCPs(RCP4.5 and RCP8.5)in the near future(2030s),middle future(2050s)and far future(2080s)were used as inputs for the Agricultural Production Systems sIMulator(APSIM)-wheat model.Analysis of variance(ANOVA)was employed to quantify the sources of uncertainty in projecting the impact of climate change on wheat grain yield.Years from 1980 to 2009 were regarded as the baseline period.The projection results indicated that wheat grain yield was expected to increase by 12.30%,17.10%,and 17.70%in the near future(2030s),middle future(2050s)and far future(2080s),respectively.The increases differed under different RCPs in different future time periods,ranging from 11.70%(under RCP4.5 in the 2030s)to 20.20%(under RCP8.5 in the 2080s)by averaging all GCMs and locations,implying that future wheat grain yield depended largely upon the rising CO2 concentrations.ANOVA results revealed that more than 97.22% of the variance in future wheat grain yield was explained by locations,followed by scenarios,GCMs,and their interactions.Specifically,at the semi-arid climate locations(Hamedan,Sanandaj,Kermanshah and Khorramabad),most of the variations arose from the scenarios(77.25%),while at the arid climate location(Shiraz),GCMs(54.00%)accounted for the greatest variation.Overall,the ensemble use of a wide range of GCMs should be given priority to narrow the uncertainty when projecting wheat grain yield under changing climate conditions,particularly in dryland environments characterized by large fluctuations in rainfall and temperature.Moreover,the current research suggested some GCMs(e.g.,the IPSL-CM5B-LR,CCSM4,and BNU-ESM)that made moderate effects in projecting the impact of climate change on wheat grain yield to be used to project future climate conditions in similar environments worldwide.
文摘Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.
文摘China is a large agricultural and the most populous country, so it is a crucial importance for the food security. The basic situation of food in our country is self-sufficiency, a certain amount of imports and reserves. The output of grain in our country has increased annually, however, as a result of policy adjustments and other factors like environmental pollution, together with a large population base and the trend of excessively popu- lous growth, the growth of grain output is relatively slow, which will be harmful for our grain security as well as the healthy development of the na- tional economy. In this case, several solutions could be tried, such as improving the level of science and technology, adjusting industrial policies and controlling environmental pollution. Besides, we ought to strongly advocate thrifty behavior to increase income and reduce expenditure.
基金partly funded by the National Key Research and Development Program of China(NK2023190801)the National Foreign Experts Program of China(G2023041024L)the Key Scientific Research Program of Shaanxi Provincial Education Department,China(21JT028)。
文摘Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB.
文摘Through an in-depth analysis of the per capita net income of rural residents in Nyingchi City,it was known that the per capita net income of rural residents in Nyingchi City was increasing at high speed in recent 10 years. However,the wage income,household operating income,and agricultural income gap constitute the major factors influencing the gap of the per capita net income of rural residents in Nyingchi City. Finally,it came up with recommendations including promoting the reasonable flow of labor to the secondary and tertiary industries,increasing the wage income and transfer income of rural residents,accelerating the construction of small towns in rural areas,promoting the development of rural cooperatives,implementing the strategy of " benefiting farmers and strengthening tourism",promoting integration of agriculture and eco-tourism,promoting the development of modern agriculture,and expanding diversified production income of farmers.
文摘Adopting Just and Pope (1978, 1979) style yield functions, this paper proposes a method to analyze the impacts of regional climate change on grain production in China. We find that changes in climate will affect grain production in North and South China differently. Specifically, it emerges that a 1℃ increase in annual average temperature could reduce national grain output by 1.45% (1.74% reduction in North China and 1.19% reduction in South China), while an increase in total annual precipitation of around 100 mm could increase national grain output by 1.31% (3.0% increase in North China and 0.59% reduction in South China).
文摘To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp, indica var. Mottaikaruppan) and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate (SDS) (1.0 g/L) and Triton-X-100 (1.0 mL/L)], whole rice grains soaked in distilled water for 12 h at 30℃were germinated in the dark at 30℃ for five days. The highest germination rate (77.1%) was obtained on the 5th day. An increase in the content of reducing sugars from 7.3 to 58.1 mg/g DM (dry matter) was observed from the 1st day of germination. Free amino acids and soluble protein contents increased to 3.69 and 5.29 mg/g DM, respectively on the 5^th day of germination. Total protein content decreased from 100.5 to 91.0 g/kg DM during germination. Increases in amylolytic (1.1 to 190.0 U/g DM) and proteolytic (0 to 0.12 U/g DM) activities were observed during germination. Effects of different concentrations of gibberellic acid on the germination of rice grains were evaluated and 0.1 g/L was found to promote germination. When effects of gibberellic acid (0.1 g/L) and surfactants were evaluated individually and together, higher germination rate was observed in the control experiment (grains germinated in distilled water), whereas giberellic acid and surfactants decreased the germination rate. Therefore, the flour obtained from the grains germinated for four days using distilled water to obtain high content of soluble materials and enzyme activities can be used in preparation of bakery items.
基金supported by the National Social Science Fund of China (14BGL093)the International Development Research Center (107093-001)+4 种基金the Specialized Research Fund for the Jointed Doctoral Program of Higher Education of China (20124105110006)the National Natural Science Foundation of China (71403082)the 2017 Annual Scientific and Technological Innovation of Henan Province Talent (Humanities and Social Sciences) Support Program, China (2017-cxrc-002)the Young Backbone Teachers Scheme of Henan Colleges and Universities, China (2015GGJS-085)the Henan Province Philosophy and Social Science Planning Project, China (2017BJJ033)
文摘Using a logistic model,this paper empirically investigated farmers’perception of climate change and its determinants based on a field survey of 1 350 rural households across five major grain producing provinces in China.The results show:i)There is an apparent difference in perception levels for long-term temperature and precipitation changes.Specifically,57.4%of farmers perceived the long-term temperature change correctly,but only 29.7%of farmers perceived the long-term precipitation change correctly;ii)The factors influencing the farmers’perceptions are almost completely different between precipitation and temperature,the former are mostly agriculture related,while latter are mostly non-agriculture related,except for farm size;and iii)Farmers are not expected to pay more attention to long-term precipitation changes over the crop growing seasons,because less than 30%of farmers can correctly perceive long-term precipitation change.Therefore,to improve the accuracy of farmers’perceptions of climate change,the government is recommended to:i)enhance education and training programs;ii)speed up land transfer and expand household land farm size;iii)develop farmer cooperative organizations;iv)invest more in agricultural infrastructure,specifically in major grain producing regions;and v)improve the agricultural environment and increase farming income.
基金Under the auspices of National Key Technologies R&D Program of China (No. 2006BAB15B02)National Natural Science Foundation of China (No. 40671009)
文摘The changes in utilization of agricultural land have gradually grown into one of the major factors impacting grain output in China. This study explores the various components of agricultural production in China from the land utilization perspective, involving changes in grain production per unit area, multi-cropping index, and adjustment of agricultural structure. Compared with the record values, different research methodologies are used to analyze the po- tential of above three components. The results indicate that grain production potential of 65.68×109kg was unexploited in 2006, in which 45.8×109kg came from the restructuring in agriculture. So we can infer that the reduction of grain production in China could be primarily attributed to agricultural restructuring in recent years. So the productive poten- tial can be fully restored by increasing agricultural investment, or recovering agricultural structure in favorable condi- tions. So we can say that China’s current condition of food security is good.
基金Supported by The Humanities and Social Sciences Planning Fund,the Ministry of Education(10YJAZH088)Humanities and Social Sciences General Project,Tianjin Municipal Education Commission(20142404)
文摘China's grain production cost has risen constantly since 2003. This paper starts from the grain production cost changes of unit area and unit quality,to analyze the reasons for China's grain production cost change in the last decade. It points out that the direct cause of changes in grain production cost is the steady growth of material and services costs,the fastest growth of labor costs and fast growth of land costs. The indirect cause of grain production high cost is the low efficiency in numerous and dispersive farmer production management,obviously insufficient agricultural infrastructure construction,waste phenomenon grain in production process and low contribution rate of agricultural technology.On this basis,it is recommended to reduce China's grain production cost and improve grain production conditions.
基金Project supported by the National High Technology Research and Development Program of China (Grant No 2007AA04Z238)the Qingdao Foundation for Development of Science and Technology,China (Grant No 06-2-2-10-JCH)
文摘In a recent paper [2002 Phys. Rev. Lett. 88 174102], Bandt and Pompe propose permutation entropy (PE) as a natural complexity measure for arbitrary time series which may be stationary or nonstationary,deterministic or stochastic.Their method is based on a comparison of neighbouring values.This paper further develops PE,and proposes the concept of fine-grained PE (FGPE) defined by the order pattern and magnitude of the difference between neighbouring values. This measure excludes the case where vectors with a distinct appearance are mistakenly mapped onto the same permutation type,and consequently FGPE becomes more sensitive to the dynamical change of time series than does PE,according to our simulation and experimental results.
文摘Analysis of recent changes in the amount and nature of cultivated land and grain potential, and the impacts of these changes on grain security in China's Mainland provides vital information for revising and developing strategies regarding protection of cultivated land and national grain security. This study examined changes in the area of cultivated land and in grain potential in agro-ecological zones using the "change rate" method. Agro-ecological subzones were used as the basic units and agro-ecological zones as the research units. We then studied changes for all of China's Mainland using the "gravity centre model" and analyzed the structural change of cultivated lands in each agro-ecological zone to investigate the changes in detail. The results show that both cultivated land and grain potential in China's Mainland decreased from 1996 to 2007. The structural and quantitative changes in each zone have caused the shift of the gravity centres of cultivated land and grain potential in China's Mainland to the northeast. Unfortunately, it is unlikely that natural and economic resources can keep up with this change. Although a large gap remains between the grain potential and the actual grain yield, the rapid loss of grain potential and the direction of change pose great threats to grain security. To ensure comprehensive grain security in China, it is vital to rethink the regional patterns of grain production according to natural conditions without jeopardising cultivated land protection(quantitative and qualitative), and consider the direction of cultivated land use and reconstruction according to local natural conditions, water and soil resources, and the level of economic development, and then work steadily to improve the grain potential.
基金Supported by Key Business Projects of Jiangsu Meteorological Bureau in 2016(20161122)
文摘To scientifically respond to the impact of climate change on winter wheat production,spike-grain structure data of winter wheat at Jiangsu Phenometeorological Observatory were taken as the sample. Based on agrometeorology,statistics and GIS analytical technique,status quo of spike-grain structure of winter wheat in Jiangsu and its climate change tendency were analyzed systemically. The results showed that climate change rate( CTR) of mature spike number( NS) was between-53. 37 and 256. 51 spikes/( m^2·10 a),and mean of whole province was 21.45 spikes/( m^2·10 a). CTR of number of grains per panicle( GNPS) was between-0. 58 and 12. 52 grains/( spike·10 a),and mean of whole province was 2. 39 grains/( spike·10 a). CTR of thousand-grain weight( TSW) was between-1. 65 and 16. 39 g/( 1 000 grains·10 a),and mean of whole province was 2. 86 g/( 1 000 grains·10 a). For the means of NS,GNPS,and TSW in whole province,they all showed the increasing trend with climate change,and they were just unbalanced among regions. Climate change induced the variation of meteorological conditions during growth period of winter wheat in Jiangsu. The variation of unity yield( UY) caused by this kind of change trend only accounted for-4. 32%-17. 23% of that in normal climate years,and mean of whole province was 6. 4%. That is to say,comprehensive impact of meteorological condition was favorable for improving the yield of winter wheat with climate change. Therefore,coordination level of winter wheat growth and real-time meteorological conditions could be regulated by breeding the varieties with wide climate suitability,regulating sowing date and density according to local production and management level,rational fertilization and applying growth regulator,to mitigate the adverse effects of climate change on winter wheat production,and reach high yield and quality.
基金funded by the China National Key Basic Research Programme (2013CB429901)the National Natural Science Foundation of China (General Programme: 41171400)+1 种基金Youth Innovation Promotion Association, CAS (2016158)the National Key Research and Development Program of China (2016YFC0503706)
文摘Mu Us Sandy Land(MUSL) of China, as a typical eco-fragile and farming-pastoral transitional region, shows great vulnerability to disturbances from cultivation activity. In this region, the conflict between cultivation activity and environmental protection has not attracted great importance until the implementation of China's Grain-for-Green Policy(CGGP) since2000. Here, using Landsat5 TM/Landsat7 ETM+ images from 1990, 2000, and 2010, we monitor the cultivation activity and land-use/cover changes(LUCC) resulting from cultivation activity in the MUSL region. Based on the data from images, we developed a series of databases of cultivated activity-induced LUCC and use them to discuss comparatively the spatio-temporal evolution trends of cultivation activity before and after CGGP implementation. These results provide evidence for managers to evaluate the implementation effectiveness of governmental policy and the influence of cultivation activity on the ecological environment of the MUSL region.