Based on remote sensing and geographic information system, the changes of spatial distribution of cropland for the past 10 years in China are studied. The results show that the total area of cropland is increasing while the cropland in the southeastern part of China is decreasing, whereas the cropland in Northeast China and the arid and semiarid areas of China is expanding. The ecological and environmental quality of reclaimed and lost cropland is evaluated. Thirteen patterns of the spatial changes of cropland in China can be classified into 13 areas correspondingly. Each area has its cropland transformation characteristics. In each area, the patterns of the former five years and the latter five years are similar on the whole. But the quantity of changed cropland is different. In some areas, the croplands increase or remain unchanged in the former five years but decrease in the latter five years, and vice versa. The nationwide warming is in better coincidence with the northward shifting of the paddy fields in China; at the same time, the drought in Northwest China causes the coexistence of considerable scale of reclamation and loss of cropland. The economic development induced rapid urbanization process is closely related with the occupancy of vast area of cropland for construction. Although the total food production is stable, the more area of cropland in a province is lost, the more production drop occurs.
Land use change is the results of interactions between physical factors and human activities, and it also leads to changes of soil nutrient. Taking Quzhou county of Hebei province as a case study, this paper analyzed the changes of land use types and the corresponding changes of soil fertilities from 1980 to 1999. The results are as follows: The convert order of land use type is from grassland to farmland, from farmland to irrigable land, from irrigable land to vegetable land; the change extent of organic matter, total-N, and available-P content is different among different land use types in 1980 and 1999, the order of content change in different land use types is irrigable land > farmland > grassland, but the range is from 2% to 18%; the order of content change in different land use types in 1999 is vegetable land > irrigable land > farmland, but the range is 18%-690%; and the change extent of organic matter, total-N and available-P content is different among different land use types from 1980 to 1999, the order of content change in different land use types is vegetable land > irrigable land > farmland > grassland.
The author finds that the character of self-similarity is very clear in Hangzhou when he studies the evolution of urban morphology and structure of urban land use using the theory of fractals. By dint of the box counting method, several maps of urban land use of different years are utilized to extract the basic data, and then the fractal dimensions of urban morphology and seven kinds of land are calculated. It is not difficult to find that most of the standard error σ are less than the criterion δc = 0.04, which was put forward by Benguigui et al. The author finds that the status of fractals of urban morphology and land use structure tend to be better with the elapse of time, which testify the viewpoint of foreign scholars about the evolving city fractals. Another important findings of the paper is that the fractal dimension of every land use is less than that of the total urban morphology, which is only a theoretical deduction before. From the viewpoint of spatial-temporal change, the fractal dimension of Hangzhou's urban morphology tends to be increasing, and in 1996 it is near D = 1.71, a mean value of fractal dimension summarized by Batty et al. As far as different urban land use of Hangzhou is concerned, the fractal dimensions of residential, industrial and external traffic land tended to be increasing from 1980 to 1996, while the fractal dimensions of education and virescence land tended to be decreasing during the same period.
With the help of ARC/INFO software, based on the information from forest resources distribution maps of Luoning County of 1983 and 1999, six indices were used to analyze spatial patterns dynamics of forest landscapes of typical regions in the middle reaches of the Yihe-Luohe basin. These indices included patch number, mean patch area, fragment index, patch extension index etc. The results showed that, (1) there was a rapid increase in the number of patch and total area from 1983 to 1999 in the study area. The fragment degree was becoming serious. (2) The fractal degree of each forest patch type became increasingly great from 1983 to 1999. The mean extension index of Robinia pseudoacacia forest, non-forest, shrub forest, sparse forest and Quercus species forest had increased rapidly, but that of economic forest became zero. (3) The changes of landscape pattern were different in different geomorphic zones. From 1983 to 1999, the vegetation cover area, the gross number and the density of patches, the diversity and evenness of landscapes were all reduced greatly in gullies, but the maximum area and the mean area of patch types were increased.
In this paper, applying landscape ecological theory, according to the principles of system comprehensiveness, regional dominance, dynamic variability, landscape ecology, scientific validity, relative independence, and manipulation, we construct landscape ecological indicators for evaluating sustainable coastal land use from the aspects of landscape productivity, landscape threatening, and landscape stability. On the aspect of landscape productivity, four indexes are chosen, that is, index of per unit area yield of crops, index of per unit area yield of aquatic product, index of per unit area total output value of industry and agriculture, and index of per unit area agricultural mechanical energy; on the aspect of landscape threatening, mostly choosing three indexes are chosen, that is, index of population density, index of land utilization ratio, and index of multiple cropping; on the aspect of landscape stability, four indexes are chosen, that is index of landscape diversity, index of landscape fragmentation, index of landscape contagion, and index of landscape fractal. The results of applying landscape ecological indicators for evaluating sustainable land use to case study in Wudi county, Shandong province, well agree with the fact.
In this study, we used a biogeochemical model that has been validated at regional and global scales to estimate the temporal and spatial variations of China's terrestrial NPP (Net Primary Productivity) and its responses to interannual climate variability in the period of 1981-1998. The results show that the average annual total NPP is about 3.09 Gt C/yr and average NPP is about 342 g C/m2. NPP exhibited an increasing trend during the study period by 0.32%/yr. In some ENSO years (e.g. 1982, 1986, and 1997) NPP decreased significantly, but the relationship between the ENSO cycle and NPP is complex due to the complex effects of monsoons and regional climatic variability. For example, in the ENSO years of 1993 and 1994, NPP did not show a clear decreasing trend, even increased with 0.12 Gt in 1994. At the national level, the precipitation is the key factor controlling the NPP variations and a weak correlation exists between NPP and temperature, but regional responses are different. Northeast China (R2 = 0.85,P < 0.01), Northwest China (R2 = 0.97, P < 0.01), Inner Mongolia (R22 = 0.97, P < 0.01), and North China (R2 = 0.96, P < 0.01) have significant correlation with precipitation. In South China, the middle and lower reaches of the Yangtze River, and Central China, the correlation is weak.
With the beginning of strategic structure adjustment of national economy in 1997, the agricultural structure adjustment is placed on the important schedule in China. On the whole each province or autonomous region can focus on the all-side adjustment of quality-structure and varieties of agricultural products, agricultural industrial structure and regional structure at different scales. Comparative typical modes may reduce to modern urban agriculture, high-quality and special use agriculture, agricultural mode driven by supporting industries, agricultural mode guided by the market, agricultural mode led and supported by the government and agricultural mode independently managed by the farmers. They are on behalf of the feasible direction of the adjustment of China's agricultural structure. The increasing ratio of distinctive agriculture is 3.1% in 1997-2000. With thorough development of strategic adjustment of agricultural structure, superior regions of farm produce and distribution, industrial straps and new patterns of agricultural bases have formed. But due to the difference of comparative superiorities, the effects of the agricultural structure adjustment are quite different. On the whole, the north excels the south, the Yellow River drainage area excels the Yangtze River drainage area, and traditional agricultural areas excel other agricultural areas. The regulation of regional policies exerts especially important function on the agricultural structure adjustment. In recent years, "decreasing foodstuff crops production, enlarging distinctive economic crops production", have become a highlight of the adjustments of agricultural structure among the regions. From 1997 to 2000, foodstuff crops seeding areas and foodstuff yield in China respectively dropped 3.97% and 6.47%. And there are 22 provinces and municipalities in China whose foodstuff yields drop visibly. The agricultural structure adjustment focuses on boosting high-quality, mass-production and regional distinctiveness of the products, but we can not attend to one thing and lose another. Loosening the vigilantness of food security necessarily leads to the big drop of food security in China and we have to attach high importance to it.
High-tech park is a new industrial spatial form, which is different from traditional industrial form. These parks have particular sites, generally settled in the suburbs of the city to avoid industrialized area and to attach the urbanized area cheek by jowl. High-tech employees and knowledge industries get together in those parks. Their innovation space is limited, however, their innovation ability is strong. Their favourable eco-environment is useful to waken personnel's inspiration. Therefore, the dynamic concordated relationships between high-tech park and the city are often going on. Population, resource, ecology, environment, economy and society constitute six aspects of relationships between high-tech park and the city. According to people's satisfactory degree for any aspect, this paper constructs an index to measure the relationship. In order to develop the high-tech park harmoniously, this paper takes Shenzhen silicon peak software park as an example, provides four means to regulate it, that is, based on GIS, making systems analysis of park natural and ecological condition; through layout, reasonably distributing the park function zones and deciding its spatial structure; through landscape design, strengthening the sightseeing effect and improving its life amenity; and through the market economy means, upgrading the area economic, ecological and social benefits.
Comparison to contingent valuation method, choice models can provide a wealth of information on the willingness of respondents to make trade-offs between the individual attributes and their likely responses to different product circumstances. The need for an assessment of the non-market benefits of preservation of Ejina Banner's ecosystem is clear. In this paper, we take it as a case to analyze the value of individual environmental attribute and aggregate changes of preservation ecosystem service. Obtaining accurate benefit estimates using CM requires detailed descriptions of the alternative use of resource. In our experiment, the results of focus group sessions indicated that the framing goals and the issue of interest can be described with five key attributes: water rates, oasis area, water quality, animal type and animal number. The attribute levels have been selected by the preservation and developing goal. The fractional factor and the blocking of the orthogonal experimental design were used to combine various attribute levels and presented to respondents as choice sets. As a line with contingent valuation method, we used a 12-page paper with maps depicting the reason why Ejina Banner's ecosystem needed preservation, by which means the ecosystem services could be restored from their current level and some choice problems. We designed the questionnaire along with the survey booklet distributing to 1000 households in the Heihe drainage basin from July to August, 2002. At the same time, a multi nominal logit model was employed to estimate the welfare of protecting Ejina Banner's ecosystem. Results from 1000 replies indicate that the estimation of willingness to pay for a change in one of the choice attributes, and aggregate value of various scenarios have been calculated according to the estimated indirect utility function. Finally, we put forward some suggestions on how to apply the choice models in developing countries, and believe future efforts can be made to apply CM efficiently accompanied with benefit-cost analysis.
In order to derive the regional dual-nuclei structure by the method of building mathematical model, this paper redefines regional accessibility and establishes the formula to calculate it. Our research indicates that the present formula of accessibility measures materially the centrality of one point in a special region. So the present regional accessibility is only the regional internal accessibility. Based on this, this paper divides the regional accessibility into two parts as regional external accessibility and regional internal accessibility. The method to measure regional external accessibility is discussed in detail. The present method fails to measure regional external accessibility because it is impossible to get the value of the regional external accessibility of the gate point. We hypothesize a virtual point located outside the region to resolve the problem. Using the new concept of regional accessibility, this paper derivates the mechanism of the model of dual-nuclei structure and parameters of its existence under the hypothetical background of homogeneous plain. It is also verified that river basin is the best background for dual-nuclei structure to appear. Other spatial structure models can be derived by varying the parameters, because regional dual-nuclei structure is merely one of the spatial structure models.
Globalization and regional integration are two crucial factors determining the regional structure of the world economy. While accelerating the development of the world economy, economic globalization is also deepening the unbalance of economic development among different countries. In order to meet the globalization, many countries adopt regional economic cooperation as a key strategy. Based on the theoretical consideration on the regional integration of the world economy, this contribution analyzes some important driving factors of the economic integration across the Taiwan Straits in view of the situation of regional integration of the world economy and the internal conditions for the economic integration across the Straits. This paper also points out that economic development level across the Straits and industrial and export structure of each side across the Straits can be compliments for each other, and the economic integration across the Straits is also a crucial move to press ahead the reunification of the motherland.
The main purpose of this paper is to study the formation mechanism, evolution model of the coastal container port system at theoretical and empirical levels. Firstly, a theoretical analysis about the formation mechanism of the coastal container port system in view of combination of institutional economics and economic geography is given, in which the competition and cooperation on overlapping hinterland or carrier among the interrelated container ports in a region are equally stressed. On one hand, with the formation of competition, the interrelated ports are divided into hierarchies of the scale and functional structure. On the other hand, with the emergence of cooperation, the interrelated ports merge into an organic whole. Secondly, in the light of the development of landlocked connection and the change of maritime space, the authors put forward a four-phase model that illustrates the dynamic development process of the coastal container port system and the rationale behind such development. According to this model, there are new dimensions of port structure, port operation, port hierarchies, and hinterland delineations at various phases. Thirdly, based on the empirical study of China's experience, the paper holds that there have been three development stages of the coastal container port system of China, that is, the birth of container ports (1972-1978), the initial development of container port system (1979-1995), and the fundamental formation of container port system (since 1996).
According to 96 data of the maximum inscribed circle diameter of Rhizocarpon geographicum lichen on the ancient bridges and buttress, toriis, tombstones, folk house, foundations and the wall of grottoes entrances in the Huashan Grottoes area, the carving time of the grottoes is likely 515-370 aBP, that is, in the middle and late Ming Dynasty (1477-1632 AD). The lithological comparisons of the grottoes and the surrounding around ancient architectures, historical materials record, and the ages of ancient China relics in the grottoes are researched. All of the above evidences can prove the lichenometric dating result. The lichenometric dating was measured on the grottoes entrances (inner grottoes has no sunlight, so the lichen can not grow), therefore, it can be inferred that the excavation to the inner grottoes can be possibly dated back to the Qing Dynasty.
The Qaidam Basin is one of the areas where the deserts of the Qinghai-Xizang Plateau are mainly distributed. These deserts are mainly found in the southern margin and southeastern part of the Qaidam Basin, and areas around the three lakes, that is, east Taijinaier lake, west Taijinaier lake, and Dabuxun lake. The extensively distributed desert and loess recorded the environmental evolution history in this region. According to the environmental records and TL-date from stratigraphy of different types of loess, eolian sand sections in southeastern margin of the Qaidam Basin, we studied the processes of desert evolution in the concerned area since the last glacial epoch. The extensive desert which appeared 21-15 kaBP indicated that the desert was intensified in the last maximum glacial epoch. The eolian sand, loess, and paleosol layers of 15-10 kaBP are overlapped in sections, which indicated that the positive and reverse changes from the occurrence of the shifting sand to the spread and the fixation have taken place many times. Since 10 kaBP the desert had experienced fluctuating evolution process of reduction and expansion along with the global environmental changes and sand-drifting still continued at present day. The modern sand-drifting activities are another episode of desert evolution process since the last maximum glacial epoch, and the subsequent activities of drifting sand of the last maximum glacial epoch in the Qaidam Basin.
The evaluation of water quality recoverability is the basis for the realization of sustainable usage of water resources. In this research project, the criteria and method for the assessment of water quality recoverability have been set up based on the analyses of mechanism of water quality recovery. Water quality recoverability in the mainstream of the Yellow River has been evaluated through the analyses of pollutant discharge and the three main pollutant concentrations including BOD, NH4+-N and volatile phenol in river water. The results show that the water quality recoverability is weak in the mainstream of the Yellow River except that it is moderate in the section of Tongguan-Sanmenxia. The contribution of physical dilution to the water quality recoverability is relatively small; and water quality recoverability is remarkably and positively correlated to the silt content in river water and positively correlated to water temperature to some extent. The weak recoverability of water quality in the mainstream of the Yellow River manifests that the environmental function is also weak. Yet the pollutant discharge to the mainstream of the Yellow River is beyond the water quality recoverability, which leads to the deterioration of water quality and exerts negative effects on sustainable utilization of water resources.
Based on the data observed from 1989 to 1998 in Ziwuling, the change of soil erosion and soil physico-mechanical properties was studied after forestland reclamation. When the man-induced factors changed the eco-environment by reclaiming forestlands, the intensity of man-made soil erosion in reclaimed lands was 1000 times more than that of the natural erosion to forestlands. From the analysis of soil physical mechanics properties, the clay content and physical clay content decreased 2.74% and 3.01% respectively, and the > 0.25 mm water stable aggregate content also decreased 58.7%, the soil unit weight increased and the soil shear strength decreased, all of which were easier to cause soil erosion. The results of the correlation analysis showed that > the 0.25 mm water stable aggregate content was the maximum affecting factor to soil erosion, the partial correlated coefficient was 0.9728, and then were soil coarse grain and soil shear strength, the partial correlated coefficients were 0.8879 and 0.6020 respectively. The relation between the >0.25 mm water stable aggregate content, the soil sheer strength and the soil erosion intensity were analyzed.
Geostatistics has proven to be useful for characterizing and mapping spatial variability of soil properties. Provided with the development of GIS and GPS, in this paper, the spatial characteristic of Ni contents in soils of Beijing was studied using geostatistics. Some 349 samples of surface soils were collected from suburbs of Beijing. Spatial structure was described with variogram. The results show that well-defined structure with nonzero nugget effect, distinct sills and ranges and can be fitted with exponential model (R2 = 0.75, p < 0.01), which is mostly influenced by parent materials. The relative range will reach 8 km. The spatial distribution of Ni contents shows that Ni contents of soils are high in southeast district and low in northwest district, which is influenced strongly by anthropogenic factors (metal smelting and petroleum industry) functioned by natural conditions of wind and river. Variogram analysis shows that the spatial structure of Ni has geometric anisotropy whose ratio is 1.3. The major axis is in NE-SW direction in which there is the longest range. In this study, using background value as standard, Ni pollution was not found in soils of Beijing.
