不同经营水平下江西森林碳汇贡献力预测分析

森林碳汇作为未来40年内实现碳达峰及碳中和中经济可行、成本较低的重要措施,加强对江西森林碳储量及其贡献力的分析,是制定江西省“双碳”措施的重要依据。本文利用全国森林资源调查数据,采用蓄积量法估算了江西省1996-2016年的森林碳储量,同时利用灰色预测模型GM(1,1)预测了江西森林碳储量。结果表明,江西森林碳储量在过去20多年以来一直在稳步增长,2031年和2061年江西森林碳储量将分别达到3.563亿t和8.154亿t;如果不断提高森林经营管理水平,森林碳储量将会在原有基础上增加30%。因此,森林碳汇对江西省实现碳达峰碳中和的贡献力度将不断加大。如果持续提高森林经营管理水平,到2061年,森林碳汇对碳达峰碳中和的贡献力度将达到76.36%。

A Review and Implication of Land Fallow System Research

Land fallow is of great significance for undertaking land reclamation, safeguarding national food security, promoting environmental improvements and ensuring the sustainable use of land resources. This paper reviews the important achievements in three areas of research on the land fallow system. It reviews and compares the land fallow system in different countries and regions of the world; it examines the response of farmers to the land fallow system and ecological environment; and it looks at the economic effects of the land fallow system. Based on Chi- na＇s rotation system for cultivated land, some relevant policy implications are put forward. Based on the different degrees of land damage, the evaluation system and the subsidy accounting standard for fallow land are formulated, and the compulsory fallow and voluntary participation of the niche fallow are targeting. The land fallow system should improve both the regulatory and the restraint mechanisms, improve the environmental awareness and en- vironmental protection skills of farmers, change the production behaviors of farmers, and encourage farmers to change to high coverage crops to protect the land. In view of the negative effects produced by implementation of the fallow system should take corresponding management and compensation measures.

Research Progress and Discoveries Related to Cultivated Land Abandonment

Using bibliometric methods,this paper analyzes the total amount and keyword composition among 910 studies in the field of farmland abandonment published in the Web of Science database from 1992 to 2019.According to the usage of keywords,existing studies are reviewed from the three aspects of monitoring and mapping,driving forces and influencing factors,and effects assessment and trade-off.The results show that:(1)At present,the extraction and mapping of abandoned farmland data mainly rely on household surveys and remote sensing technology,and combing NDVI time series with spatial information can provide abandoned farmland data with high precision.(2)The driving forces and influencing factors of cultivated land abandonment have been summarized in terms of extent,sources and attributes,respectively.Cultivated land marginalization is the fundamental driving force of cultivated land abandonment,labor migration is the direct driving force,and changes in socio-economic factors are the main driving forces.(3)The environmental effects of cultivated land abandonment are spatially heterogeneous,and temporal-spatial differences,the landscape environment,climate,cultivation and topographic features will all play decisive roles in shaping the ultimate environmental effects.Studies of trade-offs between the impacts of cultivated land abandonment mainly focus on ecosystem service function and value,while the role of spatial background is often ignored.Based on a systematic review of existing literature,this paper suggests that future efforts should carry out large-scale investigations on abandoned cultivated land at the national level,conduct multi-scale research on the driving forces of land abandonment,and conduct trade-off research on the effects of land abandonment based on national conditions.

Land Use and Ecological Civilization: A Collection of Empirical Studies

The goal of ecological civilization construction is to realize the harmonious coexistence of human and nature.Land is the spatial carrier of ecological civilization construction.Land use types or behaviors reflect the level of intensive use of land resources,leading to different ecological environmental effects,thereby affecting the level of regional ecological civilization construction.This issue,"Land Use and Ecological Civilization",discusses the theory and method of land use management in the view of ecological civilization from the aspects of land use efficiency,land use change,land multi-functional trade-off,land ecosystem service and land ecological risk by selecting 14 representative papers,providing practical reference for the formation of the land use mode and behavioral system of ecological civilization.With abundant research levels,this issue covers varied research scales such as village,county and province,various landform types such as plain and hill,and typical land use areas at home and abroad such as East China,Central China,Northwest China,Yangtze River Economic Belt and Japan.Being frontier and practical,the multidisciplinary research methods in this issue include literature research method,fractal theory,qualitative comparative analysis,VAR model,and econometrics,among others.Focusing on the prominent problems in the process of land use,this issue deeply discusses the hot topics such as land ecological efficiency,spatial behavior characteristics,land use structure optimization and ecological risk assessment.This issue not only reviews the current literature on urgent land use issues such as arable land abandonment and land use risk,but also tries to conduct trade-off and synergy analysis on the varied functions of the rural landscape and ecosystem,thus providing a theoretical and empirical basis for solving land use problems from the perspective of ecological civilization.This issue reflects the realistic urgency of guiding land use with the concept of ecological civilization,and provides theoretical guidance and technical support from the aspects of methods and research framework.Finally,this issue proposes five hot topics in the field of land use research from the perspective of ecological civilization in the future,namely,ecological management of land use structure,ecological evolution mechanism of land use process,land ecological use mode,early warning and regulation of land ecological security pattern,ecological management and control of land use behavior.

Evolution Characteristics of Urban Land Use Efficiency under Environmental Constraints in China

In the context of high-quality economic development and coordinated regional development,this paper measures the urban land use efficiency of 275 prefecture-level cities in China from 2003 to 2016,taking into account the unexpected output(environmental pollution),and explores the temporal and spatial evolution of urban land use efficiency through kernel density estimation and spatial autocorrelation analysis.The results show that:(1)From 2003 to 2016,China’s urban land use efficiency showed an overall fluctuating growth,but it remained at a low level.The mean value of urban land use efficiency has been gradually decreasing in east,west and central regions.(2)In the whole country and the eastern,central and western regions,the regional differences have been increasing,and the efficiency values of the whole country and the east have become polarized.(3)Urban land use efficiency shows a weak spatial positive correlation,but the degree of spatial agglomeration is increasing.High-high agglomeration areas are mostly distributed in the southeastern coastal areas,and extend into the central region,while most of the high-low polarized areas are the capital cities of the central and western regions.The low-high depressed areas are scattered around the high-value accumulation areas,some of which have turned into high-high agglomeration areas during the study period,while the low-low homogeneous areas are mainly distributed in the central,western and northeastern regions.Therefore,it is proposed that strengthening the utilization of urban stock land,strengthening the regional cooperation mechanism,and formulating policies which improve the efficiency of land use are effective ways to promote the intensive and economical use of urban land,as well as regional coordinated development.

Factors Influencing Farmland Abandonment at the Village Scale:Qualitative Comparative Analysis(QCA)

As a global issue,farmland abandonment is considered to be one of the most crucial fields in the study of land use change.The clarification of its driving factors plays a vital role in improving the efficiency of rural cultivated land use and ensuring national food security.This paper aims to study the factors influencing farmland abandonment in 49 villages of Ganzhou City by adopting the Qualitative Comparative Analysis(QCA).The results show that:(1)Farmland abandonment is the outcome of synergism among many factors,among which the low–level of agricultural mechanization is definitely a necessary condition in Ganzhou,and it contributes a material effect to the abandonment.(2)The path leading to farmland abandonment is not unique to the study area,and can be attributed to five different combinations.These combinations can be enumerated as:A1(a combination of convenient transportation,complete agricultural facilities,low-level agricultural mechanization,low-level land circulation,and no industrial policy support),A2(a combination of complete agricultural facilities,low-level agricultural mechanization,low-level land circulation,sufficient agricultural labor,and no industrial policy support),A3(a combination of convenient transportation,complete agricultural facilities,low-level agricultural mechanization,sufficient agricultural labor,and no industrial policy support),A4(a combination of convenient transportation,low-level agricultural mechanization,low-level land circulation,sufficient agricultural labor,and industrial policy support),and A5(a combination of inconvenient transportation,complete agricultural facilities,low-level agricultural mechanization,high-level land circulation,sufficient agricultural labor,and industrial policy support).(3)In the above-mentioned combinations,the core conditions and peripheral conditions conjointly impact on farmland abandonment.Finally,corresponding policy implications are proposed in order to further reveal the mechanism of farmland abandonment.These recommendations provide new ideas and methods for policy makers to use in making decisions and will promote the effective use of farmland.

Impact of Agricultural Labor Transfer on Agricultural Nonpoint Source Pollution: A Case Study of Jiangxi, China

A large proportion of the rural labor force in China will continue to transfer to non-agricultural sectors in the near future, which will inevitably lead to the transformation of the agricultural production mode and the structure of the farmers’ livelihood. The Chinese government is making great efforts to govern agricultural nonpoint source pollution(ANSP), and farmers’ environmental behavior is a key factor that must be considered in the formulation of agricultural environmental policies. Based on a set of micro survey data on farmers in the study area and econometric methods, this study investigates the impact of agricultural labor transfer on ANSP by considering the substitution effect of agricultural factors and the effect of agricultural economies of scale. The results show that the increase of the agricultural labor force will not be conducive to reducing ANSP, while the income increase brought by agricultural labor transfer will improve the input structure of agricultural factors and have a positive impact on ANSP reduction. Government departments should provide subsidies or incentive measures to help agricultural social service organizations to expand their coverage and increase the frequency of socialized agricultural services, in order to guide farmers in the use of environment-friendly agricultural technology to reduce the ANSP caused by agricultural factors at the source. Furthermore, it is necessary to facilitate the development of small-sized agricultural machinery suitable for small-area land cultivation.

Comprehensive Evaluation of Farm Household Livelihood Assets in a Western Mountainous Area of China: A Case Study in Zunyi City

As the foundation of farm household structure,livelihood asset status is the basis for farmers to gain opportunities,adopt livelihood strategies,resist livelihood risk,and engage in positive livelihood achievements.Quantifying farm household assets identifies future development trends that are fundamentally necessary to predict farm household vulnerability and strategy,as well as understanding farmers’current living situations.Using Zunyi City in China’s western mountainous area as a case study,we conducted stratified sampling and participatory rural investigation appraisal to collect data on the attributes of farm households’livelihood assets and livelihood strategies to establish an index evaluation system and enable evaluation and analysis of farm households with different livelihood strategies.Our research indicates that due to structural differences,total livelihood assets of farm households with different livelihood strategies are similar.Rural households have an abundance of natural and material assets and deficiencies in human,financial and social assets.Non-rural households and part-time households are abundant in human,financial and social assets and deficient in natural and material assets.

Spatial Behavior Characteristics of Land Use based on Fractal Theory:Taking Poyang Lake Area as an Example

Landscape morphology can reflect the spatial behavior of land use.Using the Poyang Lake area as an example,the landscape pattern characteristics in 1995,2000,2015,and 2018 are determined by calculating the fractal dimension,fractal stability,patch density,patch shape fragmentation,and landscape isolation,and fractal theory is used to analyze the spatial behavior of land use.The results show that building land was the land use type which consistently had the highest fractal dimension,but the fractal dimension of building land shows a downward trend,indicating that the spatial form of building land gradually developed in an orderly direction under the action of land use spatial behavior.Paddy,dryland,and forested land were the land use types which always had the lowest fractal dimension,and they are in unstable states.The calculation results of patch density,patch shape fragmentation index,and landscape isolation index supported the conclusions of the fractal analysis.One recommendation for realizing the rational layout of the land is to reduce the fractal dimension of building land through scientific and reasonable planning and to guide the orderly development of building land.For natural landscapes such as forested land,shrub forest land,high-coverage grassland,and water area,their fractal dimensions should be increased to reduce human interference and maintain their stability.Finally,the results of this study suggest that the fractal dimension should be introduced into the National Spatial Planning,and used as an index for evaluating the rationality of the regional land use pattern.

Impact of Wheat Price Changes on Farmers’Willingness to Participate in Fallow

After operating for four years,the fallow project in the groundwater funnel area of the North China Plain has produced an initial water-saving effect.However,groundwater funnel remediation is a long-term process,and grain price changes over time may affect farmers’willingness to participate in fallow.Based on the estimation by the Cobb-Douglas production function,the relationship between farmers’satisfaction with fallow compensation and planting income is analyzed based on survey data collected from farming households in Hebei,a typical province located in the groundwater funnel area.Using this data,the impact of wheat price changes on farmers’willingness to participate in fallow is simulated.The results indicate wheat price changes affect farmers’expected planting income and consequently their willingness to fallow;88%of farmers would be unwilling to participate in fallow with a 0.1 yuan per 500 g increase in the wheat price,whereas 71.4%of farmers would be willing to participate in fallow with a 0.2 yuan per 500 g decrease in the price.Finally,some policy implications are proposed,such as the recommendation that the fallow compensation should be adjusted according to the wheat price multiplied by the average wheat yield of the three years before fallow in the North China Plain.

Sustainable Livelihood Security in the Poyang Lake Eco-economic Zone:Ecologically Secure,Economically Efficient or Socially Equitable?

Sustainable Livelihood Security(SLS)remains a rarely considered yet important issue for rural sustainability and natural resource management.Particularly in China,rural SLS research in a typical area is urgently needed,but insufficient under the background of National Rural Revitalization and Ten-year Fishing Ban of Yangtze River.Focusing on the policy-targeted inland lake area,we proposed a Livelihood Security Analysis(LSA)framework by establishing an adaptive indicator system and integrating multiple econometrical and geographical methods.This study aims to evaluate the SLS in Poyang Lake Eco-economic Zone comprehensively from the three aspects of ecology,economy and society,analyze their spatial patterns,identify the main constraints,and finally give specific suggestions for improving rural sustainability management.The results showed that rural SLS in the inland great lake area tended to be vulnerable mainly due to the lagging economic efficiency and unbalanced social equality,and mediated by regional ecological characteristics.The overall SLS and Ecological Security Index(ESI)were higher in the north and lower in the south,while Economic Efficiency Index(EEI)and Social Equality Index(SEI)were at the middle level and circularly distributed around Nanchang City.The dominating factors which have greatly shaped the spatial pattern of SLS include rural per capita electricity consumption,fishery breeding area,population dependency ratio,urbanization rate,and fishery population.The obstacle degree is ranked as economic system>social system>ecological system.An outdated economy and incomplete social services are the main constraints,characterized by weak electricity consumption,limited beds in hospitals,low urbanization rate,deficient agricultural machinery power,and a small agricultural output value.Therefore,one urgent need is to activate the rural economy by reinforcing rural electric power facilities and promoting agricultural mechanization.In addition,transforming the peasants/fishermen to the non-agricultural sector should be accelerated,which will help to reduce ecological pressure,boost urban-rural integration and narrow the income gap.