反哺模式的选择与现代化进程的“缓冲带”——当代中国农民阶层分化的相关政策效应分析

改革开放以来,中国农民经历了一个持续的阶层分化过程。一方面,农业人口的比重大幅下降,但绝对数量仍很大。分化后依然极为庞大的农民数量,决定了财政直补模式不可能保证农民收入的持续较快增长,以增加农村公共产品供给为主的间接反哺模式成为可行的策略选择。另一方面,这一过程又是很不彻底的,以农民工为代表的、从农民中分化出的阶层与母体并未彻底地割断和分离。这在产生一系列弊端的同时,亦在客观上为中国现代化进程的平稳推进留下一个意义重大的"缓冲带"。

资本充足率监管压力下资本与风险的调整——基于美国商业银行数据的实证分析

基于1998-2007年美国商业银行数据,利用局部调整联立方程组模型可对资本充足率监管压力下资本与风险的调整关系进行实证分析,重点考察在于资本"缓冲带"与表外规模对资本和风险的影响,实证结果表明:资本充足率监管对不同银行实行"差别待遇",为资本充足银行提供了监管套利的可能,因而没有达到理想的监管目标;表外业务对资本和风险水平的调整存在显著影响,尤其会扩大银行的风险轮廓。

当代中国农民阶层分化的政策效应分析

改革开放以来,中国农民经历了一个持续的大分化过程。一方面,农业人口的比重大幅下降,但绝对数量仍然很大。分化后依然极为庞大的农民数量,决定了财政直补模式不可能保证农民收入的持续较快增长。另一方面,这一过程又是很不彻底的,以农民工为代表的、从农民中分化出的阶层与母体并未彻底地割断和分离。这在产生一系列弊端的同时,亦在客观上为中国现代化进程的平稳推进留下一个意义重大的"缓冲带"。

Forest resources variation along with the main rivers in typical forest re-gion of Changbai Mountain

The restoration of the riparian vegetation disturbed by human activities is one of the hotspots of watershed ecology. Through interpreting the images of Remote Sensing in 1985 and 1999, the basic information of forest resources of Lushuihe Forest Bureau, which is a typical forest area of Changbai Mountain, was obtained with support of GIS. By dividing Land covers of Lushuihe area into 10 types (water body, residential land, stump land, farming land, wetland, mature conifer forest, midlife conifer forest, mature broadleaf forest, midlife broadleaf forest, and man-made young forest) and dividing the riparian zone into four buffers (in turn, 1000, 2000, 3000, 4000 m away from the river), the changes of riparian forest resources during 1985-1999 were analyzed. The results showed that the deforestation intension has obviously decreased and the whole environment has been evidently improved, but the riparian ecosystem was still flimsy. In buffer 1, 2, 3, the area of midlife conifer forest increased largely, but the areas of other types of land covers all decreased. Midlife conifer forest had a comparatively good status in the three buffers. In buffer 4, midlife conifer forest, mature conifer forest, and mature broadleaf forest formed a forest-age rank that is helpful to stabilize the forest ecosystem and exert its functions. Area percentage of wetland decreased in buffer 1, buffer 2, and buffer 3, even in buffer 4 in which forest ecosystem rehabilitated comparatively well, so protecting and rehabilitating wetland is a very difficult task.

Spatial Distribution and Fluorescence Properties of Soil Dissolved Organic Carbon Across a Riparian Buffer Wetland in Chongming Island,China

The migration of soil dissolved organic carbon(DOC) from terrestrial to aquatic environments has important impacts on the adjacent water quality and the transport of organic and inorganic contaminants.However,few studies have investigated the sources and properties of DOC in riparian zones.A total of 34 soil samples were collected across four riparian buffer zones(Zones A-D) on Chongming Island,China.The vertical distributions of soil organic carbon(SOC) and DOC,fluorescence excitation-emission matrix(EEM) spectra of DOC and the optical indices,including fluorescence index(FI),index of recent autochthonous contribution(BIX),and humification index(HIX),were measured across the riparian environment to investigate the sources and fluorescence properties of DOC.The results showed that SOC stored in the surface soil(0-30 cm) accounted for 40%of the total soil profile SOC.The DOC accumulated in Zones A-C,which accounted for 5%of the SOC.The fluorescence EEM spectra of DOC showed that DOC contained humic-like and protein-like substances,which were mainly derived from recent plant debris by microbes.A large amount of humic-like substances were sorbed to minerals in the surface soil(0-30 cm).In addition,the riparian topography and soil physico-chemical properties(pH,EC and moisture) dictated the transformation and transport of DOC.The results suggested that EEMs could reveal the source of DOC in riparian soil systems,and that optical indices were complementary tools that revealed the characteristics of soil DOC and provided supplemental evidence about DOC sources.

Applications of Remote Sensing and GIS to the Assessment of Riparian Zones for Environmental Restoration in Agricultural Watersheds

Geographical design of riparian buffers with long-term vegetation cover for environmental restoration in agricultural watersheds needs to assess how much farmland is located in the buffers of a concerned watershed. Traditionally, this assessment was done by field surveying and manual mapping, which was a time-consuming and costly process for a large region. In this paper, remote sensing （RS） and geographical information system （GIS） as cost-effective techniques were used to develop a catchments-based approach for identifying critical sites of agricultural riparian buffer restoration. The method was explained through a case study of watershed with ll catchments and results showed that only four of the catchments were eligible in terms of higher priority for riparian buffer restoration. This research has methodological contributions to the spatial assessment of farming intensities in catchments-based riparian buffers across a watershed and to the geographical designs of variable buffering scenarios within catchments. The former makes the catchments-based management strategy possible, and the latter provides alternative restoration scenarios to meet different management purposes, both of which have direct implementations to the environmental restoration of riparian buffers in the real world. This study, thus, highlights the great potential of RS and GIS applications to the planning and management of riparian buffer restoration in agricultural watersheds.