A Methodology Framework for Regional Land-use Change Studies based on Landsat TM images: A Case Study in Northeast China

Abstract

Land-use change is an important aspect of global environment change. It is, in a sense, the direct result of human activities influencing our physical environment. This paper analyzed the land- use change in Northeast China during 1985–2000 based on Landsat TM images. It divides Northeast China into five land-use zones based on the dynamic degree model of land-use: woodland/grassland-arable land conversion zone, dry land-paddy field conversion zone; urban expansion zone, interlocked zone of farming and pasturing and reclamation and abandon zone. The findings include the obvious increase of cropland area, paddy field and dry land increased by 75 and 276 thousand hm² respectively; urban areas expanded rapidly, areas of town and rural residence increased by 76.8 thousand hm²; areas of forests and grassland decreased sharply with the amounts of 1399 and 1521 thousand hm² respectively; areas of water body and unused land increased by 148 and 514 thousand hm² respectively. This paper also discusses the driving forces in each land-use dynamic zone and finds that some key biophysical factors affect conspicuously the conversion of different land-use types. The relation between land-use conversion and DEM, accumulated temperature (≤10°C) and precipitation was analyzed and represented. The land-use changes In Northeast China resulted from the changing macro social and economic factors and local physical elements. Rapid population growth and management changes can explain the shaping of woodland/grassland-cropland conversion zone. The conversion from dry land to paddy field in the dry land-paddy field conversion zone, apart from the change of physical elements promoting the expansion of paddy field, results from two reasons: one is that the implementation of market economy in China has given farmers the right to decide what and how they plant their crops, the other factor is originated partially from the change of the dietary habit along with the social and economic development. The conversion from paddy field to dry land is caused primarily by the shortfall of irrigation water, which in turn is caused by poor water allocation managed by local governments. The shaping of the reclamation and abandon zone is partially due to the lack of environment protection consciousness among pioneer settlers. The reason for the conversion from grassland to cropland is the relatively higher profits of farming than that of pasturing in the interlocked zone of farming and pasturing. In Northeast China, the rapid expansion of built-up areas results from two factors: the existence of a small number of towns and the huge potential for expansion of the existing towns and cities. The urban land expanded mainly in areas with a gentle topographic relief and low population density.     

Relations between Environmental Right for Citizens and the Right to Use Environmental Resources owned by Company and Enterprise

Abstract

From angles of administrative law and private law, the article analyzes relations between environmental right for citizens and the right to use environmental resources owned by company and enterprise and points out three principles to balancing two relations: A principle of equal protection, a principle that general interest is superior to special interest as well as taking an account for special interest, in specific circumstances, for example, in the circumstance that clashes between environmental and economic interests can not be avoided, policy makers can put an emphasis on more important social interest according after considering weight of each interest. Finally, the article reaches a conclusion that China should establish system of environmental right for citizens from legislative and administrative levels so that a harmonious society can be constructed with guarantee.     

经济增长、市场化改革与土地违法

在当前中国经济快速增长和市场化改革逐步推进的过程中,始终面临着较为严重的土地违法问题;土地违法行为的主体不仅包括企事业单位和令人,更涉及各级地方政府以及农村集体组织.为深入了解经济增长与市场化改革对不同主体土地违法行为的影响,本文进行了初步的理论探讨,并运用全国层面的统计数据开展了相应的实证分析.结果表明,随着经济增长速度的加快,政府和企业的土地违法面积均显著增加;而土地市场化水平的提高则能有效减少土地违法的案件数.进一步地,经济增长和市场化改革对各级政府以及企事业单位、个人和农村集体组织土地违法行为的影响也存在一定的差异.本文的研究也指出,为有效控制土地违法行为的扩大,中国政府仍需采取转变经济增长方式、稳步推进市场化改革、引导企事业单位有序用地和不断完善土地督察制度等措施.     

土地非农化生态价值损失估算

随着城镇化、工业化的快速推进,我国城乡建设用地快速扩展使农用地保护面临巨大挑战,从经济机制上防止土地过度非农化尤为重要.该文对土地非农化生态价值损失过程机制进行了理论探索,建立了价值损失估算方法,并以江汉平原为例进行案例分析.研究表明:单纯的市场机制没有考虑土地非农化造成的生态价值损失,无法实现土地资源最佳配置,非农化规模偏大;土地非农化生态价值损失巨大,1987-2010年江汉平原因此累计损失73 692.11万元,人均承担49.25元;不同类型土地的生态价值损失强度有所差异,每公顷的自然保留地、水域、林地、草地、耕地非农化价值损失分别为2.459 8万元/a,2.036 7万元/a,1.262 9万元/a,0.524 1万元/a,0.354 8万元/a.文章认为,发展与保护始终是土地资源优化配置必然要面对的难题,土地非农化是社会经济发展过程中的必然现象,也是一个土地生态服务功能不断减少和消亡的过程.土地非农化虽然在一定程度上提高了土地的经济效益和社会效益,但生态效益损失巨大,可能会导致总效益净减.土地过度非农化在很大程度上是由于传统市场体系仅部分考虑了土地的经济、社会功能,而几乎完全没有考虑其生态价值导致的.作为一类负外部性,土地非农化过程中的生态价值损失如果不能得到及时遏制,快速增长的城乡建设用地需求将使农地保护面临巨大威胁,这需要将生态价值纳入土地价值体系,计入征地成本,并在一定程度上提高现行土地价格体系的合理性,防止建设用地的过度扩张,减少生态价值损失.     

Function of Agricultural Land Use and Its Evolvement in Peri-urban Area: A Case Study of Beijing

Abstract

Rapid urbanization in Beijing stimulates the urban land expansion and diminishes available agricultural land. Monofunctional agricultural land use can not meet the demand of the development of the multifunctional agriculture and urbanization any more, so multifunctional agricultural land use is going to be promoted in the city. This article proposes the evolvement of the land use change from 1992 to 2004 and discusses some evolvement views.     

Impacts of the Rising Opportunity Cost of Farm Labor on Agricultural Land Use Structure: Theory and Empirical Evidences

Abstract

Nowadays the rising of opportunity cost of farm labor comes to the forefront of attention in China. In order to understand its impact on agricultural land-use structure, a theoretical framework of household economics is formulated drawn on Low’s model. Under the theoretical framework, the impact of the rising opportunity cost of on-farm on cropping structure is deduced in theory. And then, using statistic and survey data, taking mountain area of southern Ningxia as an example, the theoretical assumes are verified. The results show that the rise of opportunity cost of farm labor leads to less diversified cropping structure.     

The spatial-temporal differentiation of green land use in Beijing–Tianjin–Hebei urban agglomeration

ABSTRACT

As the space carrier of the construction of ecological civilization, land’s green and efficient utilization is an important guarantee for realizing national sustainable development. Based on traditional land evaluation, this paper scientifically defines the green land use, puts land as one of the production factors, and brings energy consumption, environmental pollution, etc. into the input-output system to measure the green land utilization efficiency of the urban construction land of Beijing-Tianjin-Hebei Urban Agglomeration from 2006 to 2016. The study shows that the overall efficiency variation of the urban agglomeration is related with the land and environment policies. Efficiency of 2016 is higher than that of 2006, and energy and environment are the principal factors affecting the green land use. The efficiency of each city is positively correlated with its economic development, negatively correlated with the construction land expansion. Efficiency gaps in different cities are expanding. There is positive correlation with overall weak space between cities, and the partial spatial agglomeration phenomenon appears. Therefore, the green land use efficiency could be improved by improving land utilization efficiency, coordinating economic growth of construction land utilization with environmental protection and taking feasible ways to transregional renovation of the stock ecological land utilization, etc.     

南水北调丹江口库区土壤中微塑料分布特征及风险评估

为探究丹江口库区土壤中微塑料赋存特征及影响因素,通过对果园、旱地、水田和湿地进行土壤样品采集,利用密度分选、显微镜观察和拉曼光谱仪测定等方法对土壤中微塑料进行鉴定.结果表明,研究区采集的64个样本均有微塑料检出,丰度范围为645~15161 n·kg^-1.空间分布上,库尾高于库中和库首,且表层土壤（0~20 cm）中微塑料的丰度明显低于下层土壤（20~40 cm）.微塑料主要类型为聚丙烯（26.4%）和聚酰胺（20.2%）,粒径主要集中在50~500 μm之间（75%）,常见形状为碎片状（66.2%）.相关性分析显示,土壤微塑料丰度与土地利用、距水面和住宅的距离、人口密度和土壤性状密切相关.从微塑料污染风险来看,72.1%区域微塑料聚合物污染指数处于Ⅲ级和Ⅳ级,丹江口库区存在一定的微塑料污染风险.研究结果可为微塑料风险评估提供支撑.     

土地利用方式对土壤团聚体稳定性和有机碳含量的影响

探究不同土地利用方式下土壤团聚体的粒径分布、稳定性及有机碳在各粒径团聚体中的分布规律,以期为重庆地区土壤结构的改善及土壤有机碳库的维持及提高提供依据.以重庆市北碚区6种土地利用方式(针阔叶混交林、竹林、果园、旱地、水田和荒草地)为研究对象,采用湿筛法对土壤进行粒径分组,对比分析了6种土地利用方式处理下土壤团聚体和团聚体有机碳在0～20、20～40、40～60和60～100 cm土壤剖面中的分布规律.结果表明,不同土地利用方式下,土壤的结构和肥力水平存在显著的差异.在0～100 cm土层土壤的各粒径团聚体中,6种土地利用方式的团聚体粒径均以 0. 25 mm为主;其中,竹林 0. 25 mm团聚体含量最高,其次是荒草地,旱地与果园含量最低.不同土地利用方式下0. 25～2 mm的粒径团聚体主要分布在0～20 cm土层(28. 78%～50. 08%),而0. 053～0. 25 mm和0. 053 mm的粒径团聚体主要集中在40～60cm土层.在整个土壤深度内,竹林和荒草地的土壤团聚体MWD和GMD均高于其他土地利用方式,即二者的土壤团聚体稳定性较强.土壤团聚体稳定性与土壤团聚体有机碳呈极显著正相关(r=0. 569,P 0. 01),在0～100 cm土层中,土壤0. 25～2 mm和0. 053 mm粒径的有机碳含量较高,其中0. 25～2 mm的最高,平均含量为56. 54 g·kg~(-1).除旱地土壤各粒径团聚体有机碳含量在20～40 cm土层内最高,其他土地利用方式下土壤各粒径团聚体内有机碳含量均随土壤深度的增加而降低,表现出显著的表层富集现象.总体上,6种土地利用方式下,竹林和荒草地在各土层中的土壤团聚体稳定性较好,且在各土层中,竹林土壤各粒径团聚体有机碳含量最高.     

Residential Demand for Water in the Chicago Metropolitan Area1

Mieno, Taro and John B. Braden, 2011. Residential Demand for Water in the Chicago Metropolitan Area. Journal of the American Water Resources Association (JAWRA) 47(4):713‐723. DOI: 10.1111/j.1752‐1688.2011.00536.x Abstract: This paper provides the first contemporary analysis of residential water demand in humid Northeastern Illinois, in the vicinity of Chicago, and explores seasonal and income‐based differentials in the responsiveness of water use to water prices. Using a panel of system‐level data for eight water systems and controlling for seasons, weather, incomes, and community characteristics, the analysis yields low estimates of price elasticity of demand for water in line with other studies. Furthermore, price response is greater in summer and less in higher income communities. We suggest that use of seasonal pricing can help mitigate equity issues arising from differential income elasticities while taking advantage of the greater price responsiveness of summertime water use.