The Measurement and Grading of Pressure on Cultivated Land in City-level in Yunnan Province

For a long time pressure on cultivated land receives much concern be- cause of close relationship with food security. In Yunnan provice,natural conditions of mountain area are poor and the overall quality of cultivated land is ：not high. This paper selected state （city） level as research scale,calculated the pressure index on cultivated land of 16 states （cities） in Yunnan provice,revealed the level of tension states （cities） of cultivated land,provided basic basis for determining amount of culti- vated land of provice and states and developing the policy about cultivated land protection.The study indicated that pressure on cultivated land in Dehong belongs to ＂no pressure＂ grade,in Qujing and Baoshan belong to ＂critical pressure ＂grade,in Yuxi and Zhaotong belong to ＂moderate-pressure＂grade,in Kunming and Nujiang be- longs to ＂high-pressure＂ and in the rest 9 states belongs to ＂low-pressure＂grade.

Construction of the Classification and Grading Index System of Cultivated Land Based on the Viewpoint of Sustainable Development

In order to objectively and reasonably evaluate the actual and potential value of cultivated land, both social and ecological values are introduced into the classification and grading index system of cultivated land based on the viewpoint of sustainable development, after considering the natural and economic values of cultivated land. Index system construction of the sustainable utilization of cultivated land should follow the principles of economic viability, social acceptability, and ecological protection. Classification of cultivated land should take into account the soil fertility of cultivated land. Then, grading of cultivated land is carried out from the practical productivity (or potential productivity) of cultivated land. According to the existing classification index system of cultivated land, the soil, natural and environmental factors in plains, mountains and hills are mainly modified in the classification index system of cultivated land. And index systems for the cultivated land classification in plains, mountains and hills are set up. The grading index system of cultivated land is established based on the economic viability (economic value), social acceptability (social value) and protection of cultivated land (ecological value). Quantitative expression of cultivated land grading index is also carried out.

Spatiotemporal Pattern of Cultivated Land Pressure and Its Influencing Factors in the Huaihai Economic Zone, China

Cultivated land pressure represents a direct reflection of grain security. Existing relevant studies rarely approached the spatiotemporal pattern of cultivated land pressure or the spatial heterogeneity of its influencing factors from the level of economic zones.Taking the Huaihai Economic Zone(HEZ), China for case analysis, this study investigated the spatiotemporal pattern of cultivated land pressure in diverse periods from 2000 to 2018 based on a modified cultivated land pressure index and spatial correlation models. On this basis, it explored the influencing factors of the spatial differentiation of cultivated land pressure in the late stage of the study using geographical detector as well as multi-scale geographically weighted regression model. The results indicated that: 1) in the study period, the global cultivated land pressure index of the study area decreased gradually, but cultivated land pressure increased locally in a significant way, especially in the central and southern Shandong Province;2) the spatial pattern of cultivated land pressure manifested global clustering features. Hot and secondary-hot spots presented a narrowing and clustering trend, whereas cold and secondary-cold spots manifested a spreading and clustering trend;3) average slope, the proportion of non-grain crops, population urbanization rate, and multiple cropping index have significant effects on the spatial differentiation of cultivated land pressure. The former three factors were positively correlated with cultivated land pressure, and the last factor was negatively correlated with cultivated land pressure;and 4) the amount of cultivated land has increased in the central and southern Shandong Province through land consolidation which, nonetheless, failed to improve the grain production. In regards to major grain producing areas similar to the HEZ in China, the authors suggest that great importance should be given to the balance of the quality and quantity of cultivated land, the optimization of agricultural production factors and the rational control of non-grain crops, thus providing a powerful guarantee for grain security in China.

Spatial Pressure Distribution of Cultivated Land and the Analysis of Food Safety in Kunming City,China

The social and economical condition,cultivated land resources and general situation of grain production of research area are introduced.According to relevant data of cultivated land of Kunming City in 2006,taking the minimum per capita cultivated land and index model of cultivated land pressure,and combining with two conditions of per capita grain demand which are 300 kg and 400 kg,the comparative research method was used to calculate and analyze the minimum per capita cultivated land and index model of cultivated land pressure.The results show that when per capita grain demand-Gr is 300 kg,the per capita cultivated land in Kunming City has regional differences,reflects different regular patterns of spatial distribution,and presents obvious and typical radial distribution.Urban area of Kunming has the lowest point and be taken as the center,per capita cultivated land decreases progressively from suburban to the periphery;when per capita grain demand-Gr is 400 kg,under the same consumption level,cultivated land pressures of each county in Kunming City are different,and so are the driven factors;when per capita grain demand-Gr is 300 kg or 400 kg,the indexes of cultivated land pressure in Kunming are all greater than 1,cultivated land pressure is enormous,the indexes of cultivated land pressure of each county(district) have two conditions-greater than 1 and less than 2,and the reasons differ from one another.Combining with the spatial distribution characteristics of the cultivated land and food and the situation of industrial development,the countermeasures and suggestions are put forwarded to make full use of back-up cultivated land,to plan the distribution of industrial structure in each county(district) of Kunming City as a whole,to dispose cultivated land resources reasonably and so on.

Exploration on Temporal-spatial Difference of Cultivated Land Pressure and Influence Factor Analysis: A Case Study of Guangxi

Based on related statistical data during 1980-2014,change rule of Guangxi cultivated land pressure level was studied. Taking each municipal administrative division as evaluation unit,temporal-spatial change trend of cultivated land pressure level was explored by establishing pressure index model of cultivated land,and principal component analysis was used to explore the driving force of cultivated land pressure. Results showed that from 1980 to 2014 in Guangxi,cultivated land pressure was at level one in 12 years,level two in 19 years and level three in 4 years; mean of cultivated land pressure in each city during 2005-2014 was taken as average level of cultivated land pressure in the city,in which cultivated land pressure values of Chongzuo City,Baise City,Laibin City,Liuzhou City,Fangchenggang City,Nanning City,Hechi City and Guigang City were all lower than average level in Guangxi at the same period. Driving factors of cultivated land pressure index mainly contained urbanization rate,Engel coefficient of rural households(ECRH),per capita cultivated land area,total population and rural per capita net income(RPFI).

Changes in cultivated land patterns and driving forces in the Three Gorges Reservoir area, China, from 1992 to 2015

Changes of cultivated land patterns caused by major water conservation projects are rarely reported. We selected the Three Gorges Reservoir area in China to study the change in area and landscape pattern of the cultivated land in the head,central, and tail areas of the reservoir that took place between 1992 and 2015;we then studied the spatial distribution of the cultivated land in the three parts of the reservoir;finally, we studied the driving forces behind the changes in the cultivated land. The results derived are as follows.(1) During the construction of the Three Gorges Project(TGP, 1992–2015), the area of cultivated land around the reservoir decreased by30.23 million ha. This reduction occurred in phases:the most severe change in cultivated land occurred during the later stage of the project(2002–2010);only 0.62 million ha of cultivated land did not change between 1992 and 2015.(2) Spatial pattern analysis showed that the cultivated land in the three parts of the reservoir changed from a northern distribution to a southern distribution;thus, the area of cultivated land in the north decreased over the time period. The area of cultivated land in the head and tail areas decreased by varying degrees, while it increased in the central area over the 23 years, indicating that the change in cultivated land showed regional differences.(3) The TGP, the policy of reverting farmland to forest,and urbanization were the main driving factors for the change of cultivated land, but there were differences in their impacts at different stages.(4) According to the patch dynamics of the land cover change, the degree of change gradually intensified during the early and later stages of the project and then stabilized during the operational period. Our research provides scientific support for the protection of cultivated land resources and food security in the reservoir area and for the coordination of social and economic development, which is of great significance to sustainable development in the reservoir area.

Monitoring the Cultivated Slope Land in the Three Gorges Reservoir Area Based on Remote Sensing and GIS

By means of combining auto-extraction with manual interpretation, the current distribution information about cultivated land is obtained. The distribution information of 1992 is extracted from the dynamic polygons of 2002. The monitoring mini-system of the cultivated slope land is established. In the system, detailed surveys, focused on the resources of cultivated slope land, are carried out. The results indicate that the area of the cultivated slope land is very large. Meanwhile, there are lots of cultivated steep slopes with gradient above 35°. The areas of steep land cultivated had been slowly reduced from 1992 to 2002. At the same time, the pressures of returning farm land to forestry are great in all counties. The conflicts between population growth, insufficient grain supply and stagnant economic development sharpen increasingly. It is inevitable to improve the agricultural structure.

Changes in Land Use and Agricultural Production Structure Before and After the Implementation of Grain for Green Program in Western China–Taking Two Typical Counties as Examples

Soil erosion becomes a serious environmental problem in the world, especially in western China. An effective management practice called the Grain for Green Program(GGP), which was launched in 1999, aims to reduce soil and water loss and alleviate the ecological environment problem in western China. Two typical counties in western China, the Zhongxian(in Chongqing Municipality) and Ansai(in Shaanxi Province) were chosen to evaluate the dynamic changes of land use and agricultural production structure before and after the implementation of the Program in this paper. The results showed that the cultivated land area was reduced by 7.08% from 1989 to 2003. The cultivated land per person was decreased by 8.42% during 1999-2003. Moreover, the stability index of the secondary sector of the economy was increased from 0.91 in the period 1990-1999 to 0.94 in the following ten years. In addition, the stability index of tertiary economic sector increased from 0.88 to 0.92 in Zhongxian county. Meanwhile, the cultivated land area was reduced by 15.48% from 1990 to 1999. The soil erosion modulus was decreased by 33.33% from 1999 to 2006. Also, the stability index of secondary and tertiary economic sectors was 0.86 in the period 1998-2002. However, it decreased by 77% during 2002 to 2007 in Ansai County. These results imply that the Grain for Green Program had different impact on the two regions. Several effective strategies of soil and water conservation have been carried out to ameliorate the sustainable development of ecological environment and economy in these two counties of western China.

Pressure on Cultivated Land in Fengxian County,Jiangsu Province,China

Based on the introduction of the general situation of research region,pressure index model of cultivated land is adopted according to the data of population,cultivated land area,crop sowing area,grain sowing area,and unit grain yield in the Statistical Yearbook of Fengxian County.The change of relevant factors of cultivated land pressure index over time is analyzed,as well as the tension level of cultivated land resources.Research shows that the pressure on cultivated land is relatively great in Fengxian County in the years 1999-2005.Grain supply and demand is still under the unsafe state.There will be more prominent contradiction between supply and demand of cultivated land in Fengxian County in the future,and the grain security will under greater pressure.Several countermeasures are put forward to ease the pressure on cultivated land in Fengxian County,in order to realize the sustainable use of cultivated land resources,to ensure the supply and demand balance of grain and cultivated land,and to stabilize and improve the grain productivity in Fengxian County,such as protecting the current cultivated land resources by the strictest protection system of cultivated land,enhancing the intensity of land development and reclamation,enlarging the area of cultivated land,increasing the agricultural sci-tech input,and improving the grain unit yield.

Analysis of Temporal and Spatial Changes of Cultivated Land in Karst Areas of Southwest Guangxi Based on Landscape Pattern Indices

Affected by topographical conditions,the distribution of cultivated land in karst areas is relatively fragmented.More effective cultivated land protection measures can be taken in a targeted manner by grasping the spatial and temporal distribution characteristics of regional cultivated land.In this study,with the cultivated land of four county-level administrative regions(Debao County,Jingxi City,Daxin County,and Tiancheng County)in typical karst landform areas in southwestern Guangxi as the research object,combining with the spatial analysis function of the GIS software platform,the spatial distribution characteristics and temporal and spatial changes of cultivated land in the study area were investigated from 2009 to 2020 using the quantitative analysis method of landscape pattern indices,revealing the main problems of cultivated land utilization,and the multi-dimensional management ideas of cultivated land protection in karst areas under the background of rural revitalization strategy were proposed.

Analysis of the Spatio-temporal Differentiation of Cultivated Land Pressure in the Pearl River-Xijiang Economic Zone and Its Influencing Factors

Cultivated land pressure is often used to reflect the shortage of cultivated land resources. By using the methods of the Cultivated Land Pressure Index, coefficient of variation and cold-hot spot analysis, this paper analyzes the spatial-temporal differentiation pattern and dynamic change processes of cultivated land pressure in the counties of the Pearl River-Xijiang Economic Zone from 2008 to 2017, and measures the factors which influence cultivated land pressure by using Principal Component Analysis. The results show that the cultivated land pressure in the Pearl River-Xijiang Economic Zone has been in a “high pressure” state, and the Cultivated Land Pressure Index has been rising continuously from 2008 to 2017. The coefficient of variation of the Cultivated Land Pressure Index in the Pearl River-Xijiang Economic Zone and various prefecture-level cities is fluctuating and rising, which indicates that the overall spatial differences in the cultivated land pressure in this region are expanding and polarization is obvious. In addition, the area where the municipal district of the provincial capital city is located is the core area of urban development and also the area with the greatest cultivated land pressure. The spatial pattern of cultivated land pressure cold-hot spots in the Pearl River-Xijiang Economic Zone is obviously heterogeneous, in which the Pearl River Economic Zone is the main hot spot gathering area and the Xijiang Economic Zone is the main cold spot gathering area. Farmers’ income, investment in fixed assets, GDP, population and other socio-economic factors are the main factors driving the changes in the cultivated land pressure in the Pearl River-Xijiang Economic Zone. Furthermore, farming production factors, such as the multiple cropping index and grain yield per unit area,will also have an important impact on the changes in the cultivated land pressure.

兰州市耕地多功能时空演变分析

为充分了解兰州市各县区耕地利用状况,本文利用综合评价法及空间分析法对兰州市2008-2017年耕地多功能演变规律进行时空分析。结果表明,(1)从时序上来看,2008-2017年,兰州市耕地多功能主要以粮食生产功能及社会保障功能为主。(2)从空间上来看,各县区所发挥的耕地功能各不相同,其中永登县及榆中县为耕地总功能做出重要贡献。该研究结果可以为政府制定科学、合理的耕地多功能利用布局方案提供理论依据。

黄土丘陵区县域耕地时空格局变化及驱动因素分析——以天水市武山县为例

以黄土丘陵区武山县为研究对象,基于土地利用数据,运用变化轨迹分析法、面积加权平均差椭圆和景观格局指数以及土地利用预测模型,探究1990-2018年武山县耕地格局变化特征,判断各要素对其变化的重要程度。结果显示,(1)3个研究时段武山县耕地面积总体呈减少趋势,耕地重心不同时段存在差异,耕地重心先向西南转移再向东南转移。(2)3个研究时段武山县耕地变化都具有减少补充的基本特征,2000年前速率缓慢,2000年后速率加快,耕地减少面积比补充面积多,耕地减少以城关镇和洛门镇为主。(3)3个研究时段武山县耕地图斑呈现出破碎化现象,破碎化程度加剧。(4)3个研究时段武山县耕地发生变化的主要原因可以归纳为政策影响、自然环境因子影响、空间距离要素的影响,而受地理空间要素影响较小。综上,武山县耕地在28年间变化明显,武山县需要贯彻耕地保护政策和可持续发展理念,合理利用耕地。

产销平衡区粮食安全测度与时空特征研究——以云南省为例

[目的]衡量与评估粮食产销平衡区云南省的粮食安全状况,为云南省乃至全国的粮食安全科学探索与地方政府决策提供参考依据。[方法]采用质量系数优化后的耕地压力指数模型对2003—2018年云南省的粮食安全进行定量分析。[结果]从时间上看,云南省粮食安全水平总体上呈上升趋势。从数量上看,16个州(市)中,10个州(市)粮食处于安全状态,占62.50%;6个州(市)粮食安全处于不安全状态,占37.50%。从空间上看,曲靖、大理、保山、红河、文山5州(市)为中度安全,德宏、普洱、临沧、昭通、楚雄5州(市)为低度安全,丽江、昆明2市为低度不安全,西双版纳、玉溪2州(市)为中度不安全,迪庆、怒江为高度不安全,无高度安全地区;粮食安全区域主要集中在云南省东部,其次为西部,粮食不安全区域按不安全程度从高到低依次为东北部、南部及部分中部。[结论]云南省粮食安全形势整体处于不安全状态,但不安全程度较低,属于低度不安全。

基于景观指数的关中地区耕地细碎化程度的时空变迁及其驱动因素

[目的]优化陕西耕地细碎化治理,协调粮食需求增长与环境约束之间的矛盾,维护地区粮食安全和促进农业现代化发展。[方法]以关中地区为研究区,以土地利用数据和其他自然经济数据为基础,运用洛伦兹曲线、变异系数法、景观指数、空间自相关等方法构建耕地细碎化评价模型以探索关中地区耕地细碎化(Cultivated Land Fragmentation,简称CLF)的时空变迁,并利用地理探测器对区内CLF进行了驱动力分析。[结果](1)关中地区耕地资源空间分布相对均衡,耕地专业化程度保持较高水平。(2)关中地区的CLF程度变化时空差异显著,CLF程度整体呈现下降态势,但部分地区CLF程度呈增减并存趋势,整体呈现东低西高的态势。(3)关中地区CLF时空分化受多种因素影响,社会经济因素的综合影响明显强于自然因素,其中海拔高度、人口密度、人均耕地面积和地区总产值GDP为主要影响因素;因子间的交互作用效应强于单因子,以双因子增强和非线性增强为主。[结论]关中地区耕地细碎化问题在20年间得到了一定程度的改善,但呈现出较大的地区差异,应进一步在社会经济因素方面对耕地细碎化现象加强综合治理,以推动关中地区农业机械化、现代化发展。

基于土地利用现状的耕地种植属性空间分布特征研究

耕地是人类赖以生存的基本资源,耕地保护是事关国计民生的战略问题。为充分掌握耕地种植现状,及时为耕地保护提供数据参考,本文以寿光市为例,基于年度变更调查土地利用现状数据,采用核密度分析法、最近邻指数法、标准差椭圆法等方法对耕地进行统计分析,综合评估耕地及其种植属性空间分布特征,从而为后续耕地保护提供数据参考,进一步促进耕地资源可持续发展。

湖南省郴州市东河流域耕地土壤重金属污染风险评价及健康风险评估

为了解湖南省郴州市东河流域耕地土壤重金属污染情况,本文分别运用潜在生态危害指数法和健康风险评价模型,对东河流域耕地土壤重金属污染生态风险和健康风险进行了分析和评估。研究结果表明,东河流域耕地土壤Cd、Pb、As、Cu、Zn含量平均值超湖南省土壤背景值,Cd、Pb和As累积程度显著。重金属污染总体属于很强污染,研究区土壤重金属潜在生态风险危害已形成,其中Cd污染程度最高,是东河流域耕地土壤中重金属潜在生态危害的主要贡献因子。健康风险评估显示6种重金属对成人和儿童不会造成非致癌风险,对人体基本上不会造成健康危害。Pb对成人和儿童可能有潜在的致癌风险,总致癌风险指数处于不可接受范围内。因此,Cd、As、Pb是东河流域耕地重金属污染防治的重点。

鄱阳湖生态经济区建设用地扩张对耕地景观破碎化的影响

为分析鄱阳湖生态经济区耕地景观与建设用地扩张之间的关系,利用形态学空间格局分析法研究2000-2020年耕地景观破碎化的形态学特点,同时运用外溢效应分析、景观格局指数分析、地理加权回归等模型方法,探究建设用地扩张对耕地景观破碎化的影响。结果表明:2000-2020年间耕地景观破碎化程度加强,核心区面积减少强度由1.33%提高到6.27%,并表现出由平原地区向山地丘陵区加强的地域性差异,且建设用地扩张会导致耕地景观破碎化;建设用地占用耕地的面积由268.60 km2增加到1 003.26 km2,主要发生在路网成熟的地区;建设用地扩张对耕地的外溢效应逐渐增强,在路网成熟地区更显著;建设用地扩张对耕地景观破碎化有较强的正向影响,道路建设对这种影响有强化作用,同时,耕地景观破碎化表现出随道路缓冲距离的减小而加强的阶梯性差异。研究表明,耕地景观破碎化程度受地形和建设用地扩张的影响显著,耕地景观破碎化现象主要发生在地势起伏大或建设用地密集、路网成熟的地区。

陕西省生态环境对耕地利用生态效率的响应

[目的]揭示陕西省耕地利用生态效率、生态环境质量的时空分布特征,阐明生态环境质量对于耕地利用生态效率的响应方式,进而为陕西省农业高质量发展提供科学支撑。[方法]以陕西省为研究区域,基于遥感数据,计算了遥感生态指数以表征陕西省生态环境质量;利用SBM模型测度陕西省耕地利用生态效率;采用地理加权回归模型探究了生态环境对耕地利用生态效率的响应。[结果](1)2005年、2010年、2015年和2019年陕西省耕地利用生态效率总体上处于中等水平,有88%以上的地区属于低效率、较低效率和中等效率等级;(2)2005年、2010年、2015年和2019年陕西省生态环境质量在不断提高,黄土丘陵沟壑区和毛乌素沙地等地区生态环境质量有明显改善,空间格局总体上保持“南高北低”不变;(3)陕西省耕地利用生态效率和生态环境存在显著的正相关,相关关系空间分布具有不均衡性。[结论]陕西省生态环境与耕地利用生态效率的协同发展模式并不稳定,还需进一步探索与巩固。

中国耕地补充与撂荒的空间关系识别及其失衡归因

研究目的:探究耕地补充与耕地撂荒的空间匹配关系,为耕地保护和开发提供科学依据。研究方法:遥感监测、空间自相关分析、空间失衡指数、地理探测器和增强回归树模型。研究结果:(1)近20年中国耕地年均补充263.22×10^(4) hm^(2),年均补充率为1.39%,集中分布于西北、东北和西南地区。耕地年均撂荒226.68×10^(4) hm^(2),年均撂荒率为1.19%,主要分布于黄河中游和西南地区。(2)耕地补充和耕地撂荒之间以轻度失衡和不失衡为主,但极度失衡和重度失衡的单元数量逐年增加。至2020年,中度、重度和极度失衡的单元占16.87%,主要分布在西北、黄河中游、西南和南部沿海地区。(3)高—高集聚和低—低集聚是耕地补充和撂荒失衡的主要空间集聚模式。其中,高—高集聚区集中在西北、黄河中游、西南和南部沿海地区,低—低集聚区集中在东北、长江中游、西南和北部沿海地区。(4)坡度和年平均降水量为耕地补充与撂荒空间失衡主要的自然资源驱动因子,非农从业人数、农业机械总动力是主要的社会经济驱动因子。研究结论:耕地补充和撂荒之间空间失衡具有复杂性且受当地自然条件和经济社会因素的交互影响,未来应基于不同的情景和目标综合确定最优的利用模式,为高质量耕地保护提供科学依据。