Estimation of Land Production and Its Response to Cultivated Land Conversion in North China Plain

Food safety and its related influencing factors in China are the hot research topics currently,and cultivated land conversion is one of the significant factors influencing food safety in China.Taking the North China Plain as the study area,this paper examines the changes of cultivated land area using satellite images,estimates land productivity from 1985 to 2005 using the model of Estimation System for Land Productivity(ESLP),and analyzes the impact of cultivated land conversion on the land production.Compared with the grain yield data from statistical yearbooks,the results indicate that ESLP model is an effective tool for estimating land productivity.Land productivity in the North China Plain showed a slight decreasing trend from 1985 to 2005,spatially,increased from the north to the south gradu-ally,and the net changes varied in different areas.Cultivated land area recorded a marginal decrease of 8.0 × 105 ha,mainly converted to other land uses.Cultivated land conversion had more significant negative impacts on land produc-tion than land productivity did.Land production decreased by about 6.48 × 106 t caused by cultivated land conversion between 1985 and 2005,accounting for 91.9% of the total land production reduction.Although the land productivity increased in Anhui and Jiangsu provinces,it can not offset the overall adverse effects caused by cultivated land con-version.Therefore,there are significant meanings to control the cultivated land conversion and improve the land pro-ductivity for ensuring the land production in the North China Plain.

Welfare effects of rural-urban land conversion on different aged land-lost farmers:exemplified in Wuhan city

Rural-urban land conversion is a universal phenomenon in the rapid process of economic development and urban growth.The welfare of farmers who lost their farmland attracted a widespread concern within the society and academia.However,further research about differentiated policies according to the characteristics of different farmer groups is still need to be conducted.This article divides the land-lost farmers into three age groups:younger than 45,45-65,and more than 65.It proposes a welfare index system including eight functional areas based on different age groups of affected farmers,taking four districts of Wuhan City as case study area.Fuzzy mathematics method is used to derive the aggregated welfare effect index.Our analysis show that the overall welfare levels of land-lost farmers of all age groups declined,but with a varying degree,with the level of welfare in those farmers who are 45-65 years old,younger than 45 years old,and older than 65 years old decreased by 18.7%,16.6%,and 12.7%,respectively.The direction and degree of effects on the functional activity index varies among different groups.Economic conditions,living environment,health,and social participation of all age groups decrease while social security and housing conditions increase.On the other hand,development opportunities,social communication,and leisure have different changing directions in different age stages.These results call for differentiated and tailor-made compensation policies for land-lost farmers,towards improving the welfare levels of all farmers and reduce the disparity among them.

Influences of Different Transport Routes and Road Nodes on Industrial Land Conversion: A Case Study of Changchun City of Jilin Province, China

Nowadays, urban transit system has become one of the major forces underlying urban pace transformation via changing accessibility of related land parcels, which leads to the changes of land value and land use structure. This paper studied the interaction between land use changes and related transport routes, particular about how different transport routes and road nodes influence the conversion of industrial lands to residential and commercial uses respectively. Taking Changchun, an old industrial city in the rust belt of China as a case of study, we explored and compared the influences of different transport routes and road nodes on industrial land conversion. We found that surrounding the studied transport routes, more industrial lands were replaced by residential lands than by commercial lands. Also, apparent differences exist in the corridor effects of different transport routes(i.e., light rail, expressway and trunk road) and road nodes(i.e., expressway nodes and trunk road nodes) while the industrial lands convert to residential and commercial uses. Our research findings help us to illuminate the interactive relationships between transportation and industrial land conversion in old industrial cities which are undergoing social, economic and the related urban transition in Northeast China.

Payment for Environmental Services:The Sloping Land Conversion Program in Ningxia Autonomous Region of China

China＇s Sloping Land Conversion Program has been implemented since 2002. It aims to achieve goals of ecological recovery and poverty alleviation, by retiring steeply sloping land from crop production and freeing surplus agricultural labor for off-farm activities. Given the huge investment that has been poured into it, and its ecological and social impacts, this government-initiated program has attracted significant academic attention and triggered a flood of debate. Since 2004, the debate has concentrated on the sustainability of the program. Although targets have been overachieved in some provinces, concern has still emerged regarding the livelihood of farmers after subsidies stop. The present paper analyzes the implementation of the Sloping Land Conversion Program in Ningxia Autonomous Region, with a focus on the required social capital for sustained participation o f farmers and the development of off-farm economic activities.

Impacts of Cultivated Land Conversion on Environmental Sustainability and Grain Self-sufficiency in China

Using provincial data, the present paper examines the impact of cultivated land conversion on agriculture and the environment. It is found that the grain production center is gradually moving towards more fragile and water scarce areas, putting more pressure on the environment. Land conversion caused large losses in ecosystem service values in the 1990s, but large scale ecological restoration programs have been implemented since 2000 to compensate for such losses. The ecological restoration programs are concentrated in regions with relatively low land productivity, whereas cultivated land conversion usually takes place in areas with relatively high land productivity. Newly-cultivated land, especially that in areas marginally suit for agricultural production, is likely to have much lower productivity levels than the original cultivated land. Because the stock of potentially cultivable land is almost exhausted, China＇s grain self-suffiency policy can only be maintained by preserving the available stock of arable land and increasing its productivity in a sustainable way.

Practical Application of Participatory Approach in Land Conversion Project Planning: A Case in Quxian County, Sichuan Province

Application of participatory approaches in governmental forestry projects is a bran-new forestry design method. The purpose is to plan the utilization of land correctly, and to determine planting sites, planting species, participating households and management models, based on the projects' requirements and the farmers' demands. Participatory approaches are now practiced in some of the counties in Land Conversion Project. The paper presents the significance and necessity of practicing community mechanis...

Mutual Conversion of Land Use between Urban and Rural Area in the Process of Urbanization: A Case Study of Shandong Province

Urbanization is one of the driving forces for the land use change in type and structure, and its prominent effect is to convert rural land to urban land. This paper takes Shan-dong Province as an example to analyze the current situation of the mutual conversion between the urban and rural areas from the aspects of the structure of land use, the decreasing tendency of the cultivated land, the changes of land use in urban and rural residential areas. It points out that cultivated land is converted to residential area land, industrial and/or mining area land. The relationship between the urban area land and the cultivated land is more direct; meanwhile, the changes of rural residential area lag behind obviously. The decrease of the cultivated land and the decline of soil quality will be the two difficult problems in the process of urbanization.

Analysis on the Influencing Factors and Control Measures of "Non-Grain Conversion" of Cultivated Land in Agricultural Land Transfer

Through the method of literature analysis,this paper analyzes the present situation of the"non-grain conversion"of cultivated land in the transfer of agricultural land in China,summarizes the influencing factors and consequences of the phenomenon of"non-grain conversion"of cultivated land in the transfer of agricultural land,and finally puts forward some measures.The study found that costs and benefits are the fundamental factors affecting the"non-grain conversion"of cultivated land in agricultural land transfer,and other main factors include government and policy guidance,industrial and commercial capital to the countryside,labor transfer and so on.The"non-grain conversion"of cultivated land in the transfer of agricultural land is a serious threat to China s food security,leading to the decline of the quality of agricultural land and the destruction of the ecological environment,as well as the risk of breach of contract in"industrial and commercial capital to the countryside".Based on the understanding of the influencing factors of non-grain conversion,this paper puts forward the following measures:strengthening the control of the use of cultivated land in agricultural land transfer;implementing accurate subsidies for grain cultivation and ensuring the benefit of grain growers;adopting grain planting incentive mechanism to increase grain enthusiasm;strengthening media publicity and education to enhance food security awareness.The improvement of the current situation of the"non-grain conversion"of cultivated land in the transfer of agricultural land will be of great significance to the protection of agricultural land and food security in China.

Importance and Countermeasures of Curbing the Conversion of Agricultural Land to Non-agricultural Land under the Background of the Rural Revitalization Strategy

Farmland is the most basic element for farmers’survival and development,and has a social security function.The conversion of agricultural land to non-agricultural land has gradually become the primary factor in the reduction of agricultural land in various regions of China,seriously endangering China’s food security.Under the background of the rural revitalization strategy,the emergence of the conversion of agricultural land to non-agricultural land and the inevitability of its development were analyzed from both the acceleration of urbanization and the increase in land demand by using the literature research method.The importance of curbing the conversion of agricultural land to non-agricultural land to achieve the grand goal of strong agriculture,beautiful rural areas,and rich farmers was clarified,and then countermeasures and suggestions to curb the conversion of agricultural land to non-agricultural land were put forward,which is of great significance to promoting the effective implementation of China’s rural revitalization strategy.

Effects of land use changes for ecological restoration on soil moisture on the Chinese Loess Plateau:a meta-analytical approach

Soil moisture is an important resource for plant growth on the arid and semi-arid Loess Plateau of China where the‘‘Grain for Green’’project was launched in 1999,but there has been no systematic evaluation of soil moisture from the effects of ecological restoration at a regional scale.We systematically assessed 63 published studies during 2000-2015,including 2050 observations at 68 sites on the Loess Plateau with the aim of determining soil moisture changes and the factors influencing those changes.We found that,after land use conversion,soil moisture decreased by 17%in the upper 100 cm soil layer and that tree plantations and shrub lands appeared to cause soil moisture depletion which became increasingly serious with soil depth.The decrease of soil moisture was significantly influenced by the planting species in all restoration types(tree plantations,shrub lands,and grasslands).We also found that tree plantations and grasslands converted from farmlands consumed more soil moisture than from wasteland(including bare land,abandoned land and wild grasslands).Artificial restoration led to significant soil moisture reduction,but natural restoration had little effect on soil moisture.Therefore,natural restoration should be an alternative restoration practice on the Loess Plateau.These results will provide helpful information for artificial afforestation and planning ecological restoration campaigns for policy makers on water-limited regions.

Land-Use Change on Soil C and N Stocks in the Humid Savannah Agro-Ecological Zone of Ghana

Land-use conversion and unsustainable farming practices are degrading native forest ecosystems of Ghana’s humid savannah agro-ecological zone. This study assessed the impact of land-use change on soil C and N stocks in different land-use systems and soil types. A total of eighty (80) composite soil samples at two depths (0 - 20 cm and 20 - 50 cm) were sampled from five land use types (Forest, Woodland savannah, Grassland, Fallow and Cropland) for laboratory analyses. Particle size distribution, bulk density, pH, SOC and TN were determined using standard procedures. Results of the study indicated that C and N stocks were significantly lower in croplands (p < 0.05) compared to other land-use systems. There were significant interactions (p < 0.05) within land-use systems, soil types, and soil depth for soil C and N stocks. Acrisol and associated soils had the highest C and N stocks. A strong positive significant correlation (p < 0.05) was observed between C and N stocks with an R2 value of 0.85 and 0.93 for the 0 - 20 and 20 - 50 cm depth, respectively. Soil C and N stocks in the study area were estimated to be 34.56 kg/m2 and 4.63 kg/m2 for soil types and 26.89 kg/m2 and 3.39 kg/m2 for land use types, respectively for the 0 to 50 cm soil depth. Our findings indicated that the conversion of native forest to arable land has significantly reduced soil C and N stocks in the top 50 cm (0.50 m) soil layer by 50.77% and 47.77%, respectively. Therefore, we conclude that land-use change, soil type, and soil depth influenced soil C and N stocks of land-use systems in the humid savannah agro-ecological zone of Ghana.

Conversion of Andean montane forest to exotic forest plantation modifies soil physicochemical properties in the buffer zone of Ecuador's Podocarpus National Park

Background:Andean montane forests(AMF)are biodiversity hotspots that provide fundamental hydrological services as well as carbon storage and sequestration.In recent decades,southern Ecuador AMFs have been seriously threatened by increased logging and conversion to forest plantations with exotic species.In this context,our main objective was to evaluate the effects of AMF conversion to forest plantations on soil physicochemical properties in the buffer zone(Bz)of the Podocarpus National Park(PNP),in southern Ecuador.For this purpose,random samples were taken at a depth of 0-10 cm in four plots in each contrast zone and analyzed for bulk density,porosity,textural class,leaf litter depth,soil pH,as well as the contents of organic matter(SOM),soil organic carbon(SOC),total nitrogen,and available phosphorus and potassium.Results:The results indicate that the conversion of AMFs produces an increase in bulk density and a decrease in SOM,SOC,and total nitrogen contents,thus modifying soil properties,which could result in a decrease in water regulation capacity and produce an increased risk of soil erosion.This accelerates degradation processes,as well as threatens shortages of the drinking water supply.Conclusions:This study can help decision-makers to implement soil management plans in the Bz of the PNP,based on the implementation of new regulations,where the conservation of AMF is promoted.In addition,it is recommended to apply environmental restoration strategies in the anthropized areas of the AMF,as well as in the areas with exotic eucalyptus and pine plantations.

Addressing nonresponse bias in forest inventory change estimation using response homogeneity classifications

Estimating amounts of change in forest resources over time is a key function of most national forest inventories(NFI). As this information is used broadly for many management and policy purposes, it is imperative that accurate estimations are made from the survey sample. Robust sampling designs are often used to help ensure representation of the population, but often the full sample is unrealized due to hazardous conditions or possibly lack of land access permission. Potentially, bias may be imparted to the sample if the nonresponse is nonrandom with respect to forest characteristics, which becomes more difficult to assess for change estimation methods that require measurements of the same sample plots at two points in time, i.e., remeasurement. To examine potential nonresponse bias in change estimates, two synthetic populations were constructed: 1) a typical NFI population consisting of both forest and nonforest plots, and 2) a population that mimics a large catastrophic disturbance event within a forested population. Comparisons of estimates under various nonresponse scenarios were made using a standard implementation of post-stratified estimation as well as an alternative approach that groups plots having similar response probabilities(response homogeneity). When using the post-stratified estimators, the amount of change was overestimated for the NFI population and was underestimated for the disturbance population, whereas the response homogeneity approach produced nearly unbiased estimates under the assumption of equal response probability within groups. These outcomes suggest that formal strategies may be needed to obtain accurate change estimates in the presence of nonrandom nonresponse.

东北地区农业结构转型时期土地利用变化的成因与效应

During the last decade of the 20th century, extensive conversion inagricultural land use took place in Northeast China. The goal of this study is to ascertain itsspatial distribution and regional differentiation, determine its causes, and analyze itsenvironmental impact. Especially we attempt to elucidate how institutional constraints havefacilitated the change at a time of agrarian restructuring when newly emerging free market washybridized with the former planned economy. Information on six categories of land use was mappedfrom interpretation of Landsat TM images recorded in 1990, 1995 and 2000. Most of land use changestook place during the first half of the decade, coinciding with abrupt and chaotic changes ingovernment directives. Farmland was changed mainly to woodland, water body and built-up areas whilewoodland and grassland were converted chiefly to farmland. Spatially, the change from farmland towoodland was restricted to the west of the study area. The change from grassland to farmland tookplace in the grazing and farming interlocked west. These chaotic and occasionally conflictingchanges were largely caused by lack of stability and consistency in agricultural land use policiespromulgated. They have exerted adverse impacts on the local environment, including land degradation,increased flooding, and modified climate regime.

Cultivated land change in the Belt and Road Initiative region

The Belt and Road Initiative （BRI）-a development strategy proposed by China - provides unprecedented opportunities for multi-dimensional communication and cooperation across Asia, Africa and Europe. In this study, we analyse the spatio-temporal changes in cul- tivated land in the BRI countries （64 in total） to better understand the land use status of China along with its periphery for targeting specific collaboration. We apply FAd statistics and GlobeLand30 （the world＇s finest land cover data at a 30-m resolution）, and develop three indicator groups （namely quantity, conversion, and utilization degree） for the analysis. The results show that cultivated land area in the BRI region increased 3.73x10^4 km2 between 2000 and 2010. The increased cultivated land was mainly found in Central and Eastern Europe and Southeast Asia, while the decreased cultivated land was mostly concentrated in China. Russia ranks first with an increase of 1.59x10^4 km2 cultivated land area, followed by Hungary （0.66x10^4 km2） and India （0.57x10^4 km2）. China decreased 1.95x10^4 km2 cultivated land area, followed by Bangladesh （-0.22x10^4 km2） and Thailand （-0.22x10^4 km2）. Cultivated land was mainly transferred to/from forest, grassland, artificial surfaces and bare land, and transfer types in different regions have different characteristics： while large amount of culti- vated land in China was converted to artificial surfaces, considerable forest was converted to cultivated land in Southeast Asia. The increase of multi-cropping index dominated the region except the Central and Eastern Europe, while the increase of fragmentation index was prevailing in the region except for a few South Asian countries. Our results indicate that the negative consequence of cultivated land loss in China might be underestimated by the domestic-focused studies, as none of its close neighbours experienced such obvious cultivated land losses. Nevertheless, the increased cultivated land area in Southeast Asia and the extensive cultivated land use in Ukraine and Russia imply that the regional food production would be greatly improved if China＇ ＂Go Out policy＂ would help those countries to intensify their cultivated land use.

Spatially explicit estimation of soil organic carbon stock of an estuarine mangrove wetland of eastern India using elemental analysis and very-fine resolution satellite data

Background:This study estimated the total soil organic C(SOC)stock of the wetland influence zone of Bichitrapur mangroves in eastern India in a spatially explicit manner.Both spatial and vertical distribution of SOC densities with respect to land use/land cover(LULC)pattern were assessed.Subsequently,some site-specific management strate-gies were forwarded towards enhancement of C sequestration potential.Methods:The changing patterns of LULC within the wetland influence zone of the site were analyzed using Landsat TM(30 m)and Pleiades-1A(2 m)imageries from 1988 to 2018.Point-specific SOC measurement was done using samples taken from four core-depth intervals(viz.D1:0–20 cm,D2:20–40 cm,D3:40–70 cm,D4:70–100 cm)at 89 locations belonging to different LULC categories.Spatial interpolation was applied on this point-based data to produce SOC density and stock models as a whole and at all core-depths.Relationships between SOC density,core-depth and present LULC were evaluated through multivariate statistical analyses.Results:The LULC transformations during last three decades suggested the gradual growth of mangrove plantations as well as agricultural and aquacultural activities.Most amount of SOC was concentrated in D1(37.17%)followed by D3(26.51%),while D4 had the lowest(10.87%).The highest mean SOC density was observed in the dense mangrove patches(248.92 Mg ha^(−1))and the lowest mean was in the Casuarina plantations(2.78 Mg ha^(−1)).Here,Spline method emerged as the best-fit interpolation technique to model SOC data(R^(2)=0.74)and estimated total SOC stock of the entire wetland influence zone as 169,569.40 Mg and the grand mean as 125.56 Mg ha^(−1).Overall,LULC was inferred as a major determinant of SOC dynamics with a statistically significant effect(p<0.001),whereas no such inference could be drawn for soil core-depth.Conclusions:The C sequestration potential of sites such as the present one could be increased with appropriate zone-wise plantation strategies,restriction on the land conversion to aquaculture and promotion of ecotourism.Peri-odic monitoring through integration of geospatial techniques and elemental analyses would be immensely beneficial in this regard.

Does the ecological concept of disturbance have utility in urban social-ecological-technological systems?

The ecological concept of disturbance has scarcely been applied in urban systems except in the erroneous but commonplace assumption that urbanization itself is a disturbance and cities are therefore perennially disturbed systems.We evaluate the usefulness of the concept in urban ecology by exploring how a recent conceptual framework for disturbance(Peters et al.2011,Ecosphere,2,art 81)applies to these social-ecological-technological systems(SETS).Case studies,especially from the Long-Term Ecological Research sites of Baltimore and Phoenix,are presented to show the applicability of the framework for disturbances to different elements of these systems at different scales.We find that the framework is easily adapted to urban SETS and that incorporating social and technological drivers and responders can contribute additional insights to disturbance research beyond urban systems.

Occurrence factors of large vacant lots in central districts and their utilization by local governments in Japan

In Japan, focal cities experience a number of probtems retated to deterioration of residentiat environment, quality of public service, and vitalization of commercial rand. SpecificaLLy, the presence of Large vacant tots behind sizable stores, office buildings, hospitals, and factories devitatize urban activity and its Landscape. Many local cities are seeking to actuatize a sustainable compact city with an integrated poputation, commerce, traffic and other pubLic services in ways that promote a tow carbon and energy-conserving society. Against the backdrop of these issues, this study examines the occurrence of large vacant lots and their utilization by tocat governments in Japan based on a questionnaire and fietd survey. It highlights severat cases in which a Large vacant tot is used to forward the development of a compact city by a tocat government.