Accurate information on pattern of arable land inputs by crops is important for ensuring national food security in China. The crops were divided into cereal crops, legume crops, oil crops, fiber crops, sugar crops and vegetable crops in this paper. Then total inputs of arable land in China were estimated based on the data pertaining to crops sown area and its cost per unit area, which were respectively gathered from the China Statistical Yearbook and National Farm Product Cost-benefit Survey. Furthermore, the temporal and spatial variations of China’s cultivated land use inputs by crops were analyzed at the provincial level. The results show that: 1) Total inputs of arable land in China grew strongly from 27.67×1010yuan in 1998 to 38.15×1010yuan in 2011, while the growth was mainly attributable to the increase of vegetable crops inputs. Vegetable crops inputs were higher than cereal crops in 1999, and have become the biggest input crops since then. Thus, it is concluded that the pattern of arable land inputs is shifting from cereal crops to vegetable crops. 2) There were marked differences in the arable land inputs and its growth rates from the provincial point of view. Provinces with higher arable land inputs were concentrated in the Huang-Huai-Hai Plain; meanwhile, the lower inputs provinces were mainly located in northwestern China. The increase of arable land inputs in northern and southwestern China was higher than the other regions from 2001 to 2011, with a rate of more than 50%. 3) The proportion of cereal crops inputs to arable land total input in China’s main grain producing regions was higher than the other regions, compared with that the proportion of vegetable crops inputs was comparatively higher in the eastern coastal zone. The increase of cereal crops and vegetable crops inputs in developed regions was largely due to the rise in intensive use, while the increase by cereal crops and vegetable crops inputs in most western provinces was attributable to the enlarging sown area.
Based on the theory of resources field and potency, the obtainable data on coal resources potency, coal task potency and coal resources-task potency of China’s 30 provinces (autonomous regions or municipalities) from 1986 to 2010 are calculated, and the characteristics of their temporal and spatial changes are analyzed in this paper. The result demonstrates that 30 provinces in China can be classified into three types: coal field source zone, coal field collection zone and basic equilibrium zone. And then the basic characteristics of coal resources spatial allocation are concluded, and the rationality of coal resources spatial allocation in China in 2010 is evaluated. Several conclusions are obtained as follows:
Firstly, the coal resources potency began to change before 2000, and the coal resources has tended to centralize in Shanxi and Henan, but shifting from the northeast to the northwest with the elapse of time. Secondly, coal task potency maintains relatively stable, only accompanying with a small scale change, presenting similar spatial distribution with coal resources potency in general. Thirdly, most provinces need to transfer coal from other provinces, coal resources-task field tends to gather in the eastern and southern coastal areas and regions of Shanxi, Shaanxi and Inner Mongolia. At present, "S-shaped" input zone mainly consists of the eastern and southern coastal areas, and the Bohai Rim and "V-shaped" output zone mainly covering Shanxi, Shaanxi and Inner Mongolia have been formed basically. Fourthly, coal spatial allocation types of China’s 30 provinces are identified as field source zone (6 provinces), field collection zone (19 provinces) and basic equilibrium zone (5 provinces). There are significant regional differences in the direction and intensity of coal spatial allocation, phenomena of spatial polarization strengthens the regional function and clarifies the regional division of labour. Fifthly, China’s coal spatial allocation is reasonable in general, but due to irrational allocation in direction and intensity in individual regions, the problems of too much output from source zone and excessive input in collection zone still exist in several regions.
The main influencing factors of carbon emission performance include economic structure, energy consumption structure, regional division of work and technical level of high-carbon industry. Although these indicators are in a certain degree of influence on CO2 emissions per unit of GDP, it is difficult to measure the contribution of each indicator. In this paper, we selected the four main indicators mentioned, according to the entropy method to measure the weight of each indicator, applying multi-indicators cluster analysis methods under the index system, and dividing the whole country into 7 typical areas. The analysis result shows: the characteristic of the regional division of work, which has the largest weight of 0.4567, is the main factor resulting in regional differences in China’s provincial carbon emissions performance, then the energy structure and the technical characteristics of high carbon industry take the second place. The indicator of economic structure, with a weight of 0.0971, has a limited contribution to explain the regional differences at the provincial level of carbon emissions. In northern regions, the high share of high-carbon production market and low technical level results in low carbon emission performance. Especially in North China, the high proportion of coal in the energy consumption has a negative effect on carbon emission performance; in southeast coastal areas, due to its advanced technology, the negative effect from high share of high-carbon production has been offset to some degree; although the share of high-carbon production in central and western China is much lower than in the eastern regions at present, yet the technical level is low. The carbon emission performance decreased with a backward technical level. There are differences among the historical development of provinces; natural resource endowment and regional division of work, complying with the macroeconomic development of objective laws and economic location theory, in addition to a small number of developed areas, the other regions in China are difficult to change their economic and energy structure in a short period of time. The low-carbon policies should be focused on improving the technical level of high-carbon industries.
Water scarcity is the most severe constraint to socio-economic development in arid regions. It calls for water demand management to control rapid increase of water demand and to alleviate conflicts between water demand and supply. There are two kinds of water demand management policies, i.e., price control which is based on market mechanism and quota control which is based on administrative management. This paper assumes that the water structure changed along with the upgrading of industrial structure under the zero growth of total water requirement and examines the effectiveness of price control and quota control measure for reducing water demand based on a distributed water-economic model (GBEM). The results show that quota control measure is more effective than price control in curbing water demand. The current price of irrigation water is too low compared with shadow price of water resource so that farmers will not respond to water price change unless water price was raised at the level of shadow price of water resource. To save same amount of irrigation water, farm income under water price control will loss much more than that under quota control. The farm income loss under water price control consists of increased irrigation cost and change of cropping system. The farmer income loss under quota control is caused by decrease of sown areas. Both of the two kinds of policy instruments need to consider benefit compensation to farmers. The two kinds of water demand management policies have less impact on food security. However, cash crops production will change while water demand management policies are implemented. The crops which need more irrigation water will decrease if water price is raised, while quota control measure is implemented, cropping system will shift from the crops with low water efficiency to the crops with high water efficiency.
Bay-type city is a recognization of cities in terms of spatial development morphology, it is also a kind of goal-directed promoting urban development. Recognization of bay-type city and ecological construction of waterfront space are of great importance to the development of cities. Based on the scarcity of gulf resources, this article specifies the significance to the optimization of city space and maintenance and improvement of urban ecological system by defining the bay-type cities as well as waterfront areas, and analyzing the characteristics of their space structure. Due to the fact that location advantage plays an important role in the determination of urban characteristics, urban scale, industrial structure, development trend and strategies, the author brings forward the development orientation of bay-style cities on the basis of their dominance, and also determines their strategic goal and general development direction by analyzing the location advantage. Accordingly, optimization of ecological pattern is adjusted and controlled, which is the emphasis and key point to realize the ecologicalization of urban structure, and also the foundation to construct the basic ecological framework and the earth utilization framework. Based on the region component of urban ecology system and function difference, the basic ecological frameworks of ecological caring section in Maluan Bay, ecological rebuilding section and ecological transition section have been established, which accounts 22%, 70% and 8% of the 69 km2 key area respectively. On the basis of expanding waterfront space of bay-type cities, this article aims to construct a urban function group of great variety and equilibrium layout by balanced calculation of earth utilization in ecological rebuilding section and division of function areas, eventually to realize the dynamic integration of functions in different areas.
Litters are the important component of forest ecosystem and play a key role in plant growth and ecosystem nutrient cycle. The Tibetan Plateau is a unique geographical cell on earth with an average elevation above 4000 m a.s.l., where forest has been known for exclusive tree species with special distribution law and rare highly productivities. Dark conifer forests make up 48% of forest areas and its stock volumes also make up 61% of total volumes in Tibet. Picea likiangensis var. linzhiensis which has been distributed in Linzhi and Shannan region of Tibet is one of the dominant tree species in these dark conifer forests. To understand the nutrient return through the litter in the primary Picea likiangensis var. linzhiensis forests which were located in Nanyigou area of the Tibet, ten 1 m×1 m litter traps made of nylon mesh (1 mm mesh size) were arranged randomly in the 50 m×50 m fixed sample plots which were located at the more than 20 m away from the forest edge area. The litter was collected at monthly intervals from January to December. Meanwhile six 1 m×1 m samples were arranged randomly in the 20 m×20 m sample plots which were located near the fixed sample, the whole litter was collected from the un-decomposed layer, semi-decomposed layer and decomposed layer, respectively. The results showed the annual litter in the Picea likiangensis forests were 3.40 t·hm-2, the leaf litter and the branch litter constituted 24.29% and 26.07% of the total annual litter, respectively. During the whole observation year, the concentrations of N, P, K and Mg in the litter were lower than in the living organisms. The total annual nutrient returns of N, P, K, Ca and Mg were 82.14 kg·hm-2. Among them Ca return was higher than those other four nutrient elements. The thickness of litter layer reached to 5.0 cm and the standing stock was 40.65 t·hm-2. The average annual decomposition rate of litter layer was 0.08 t·hm-2. The total amount of five nutrient elements was 937.65 kg·hm-2, of which decomposed layer was 57.28%. In this study, we found the standing stock of Picea likiangensis var. linzhiensis forests in Tibet was far lower than those of the forests in Tianshan Mountains, but was higher than those of Abies forests in Ermeishan Mountain. However, the litter from Picea likiangensis var. linzhiensis was very difficult to be decomposed because the thickness of decomposed layer was only 24% of the whole litter layer. This study also proposed shrub played an important role in improving the fertility in primary forests.
With continuing population growth and rapid economic development,coupled with increasingly serious water pollution,growing shortage of available water resources,water crisis shows up in many regions.Evaluation of the regional water shortage is the basis for the study of water resources risk. Previous studies, with the use of a single evaluation method, resulting in differences in evaluation results. In this paper, the circulating correction model derived from a single evaluation method generated a combination correction of the evaluation results. Comprehensive evaluation index system constructed indicates water shortage in Yunnan Province as well as aspects of water economics,construction control,water supply,water usage and water environment. The use of fuzzy matter-element, fuzzy pattern recognition, and other single evaluation method, finally, gains a combination of three evaluation methods, namely, average method, Boarda method and Compeland method for the different evaluation results.The Kendall test and Spearman test methods were carried out for pre-and post-conformance tests to ensure reliability of the model cycle correction in this paper. The establishment of the degree of shortage of water resources evaluation model based on the circulating correction mode and application, gives the present status of Yunnan Province including 16 cities in terms of degree of water shortage as well as the lack of water type in 2010, and corresponding countermeasures are put forward.
Based on meteorological and hydrological data of the Kuye River on the Loess Plateau from 1956 to 2005, the paper studied the variation tendency, the abrupt and periodic changes of annual streamflow using the nonparametric test, R/S analysis, wavelet analysis and frequency analysis. The empirical equation which shows the relationship between rainfall and runoff was established to estimate the impact of human activities on the runoff variation. The results showed that the annual streamflow in the river basin declined markedly with 0.11×108 m3/a. The change points occurred in 1979 and 1996. The frequency analysis showed that, compared to period 1 from 1959 to 1979, the runoff reducing extent at 5%, 50% and 95% in period 3 from 1997 to 2005 was greater than that in period 2 from 1980 to 1996. The main periods are 9 a, 18 a and 32 a. Compared to period 1, the contribution rates of climate change and human activities were 58.62% and 41.38%, respectively in period 2. In period 3, the contribution rate of human impact increased to 78.25% of streamflow change, in which the impact of coal mining being 52.27%. The human activities were the main driving force for the decrease of runoff; however, the influence of climate change cannot be ignored. Their impacts should be taken into consideration when carrying out comprehensive improvement of soil and water conservation and rational use of water resource.
Beijing is an international metropolis with serious shortage of water resources. Water scarcity in addition to serious water pollution has made water a major constraint for future socio-economic development and ecological security. In this study, we use grey water footprint as an indicator to quantify the effects of water pollution on the amount of freshwater resources from agricultural, industrial and domestic sectors in Beijing during 1995-2009. These effects are presented as the volume of water that is needed to dilute the water pollutants. The results show that: 1) Grey water footprint of Beijing in 2009 is 4.95 billion m3/a, about 2.3 times that of the total amount of water resources in the same year; 2) domestic sector has the largest grey water footprint, followed by agricultural. Industrial sector has the smallest grey water footprint; 3) the grey water footprint of Beijing has declined year by year. Since 1995, the grey water footprints of agricultural, industrial and domestic sectors have decreased by 45%, 93% and 62%, respectively; and 4) although the grey water footprint of Beijing has dropped gradually, the ratio of water bodies reaching water quality standard has shown a decreasing trend. The grey water footprint is much higher than the amount of water resources, leading to accumulation of pollutants in the water bodies. It is not possible to dilute such a large amount of pollutants emitted into natural water bodies only by relying on the self-purification capacity of water bodies. So the residual grey water footprint has a positive sign and the accumulation of residual grey water footprint has increased year by year. As a result, water quality continues to deteriorate. The growth of the accumulation of residual grey water footprint explains the reasons why the quality of water becomes worse even with decreasing grey water footprint. The grey water footprint should be controlled in order to improve the aquatic environment in the Beijing city.
By using the observed wave data from September 2006 to August 2011, the wave energy resource was analyzed. In order to analyze the wave energy resources reasonably, the value of wave energy density, frequency of effective SWH (Significant Wave Height) and wave energy storage were exhibited. Results show that: 1) Wave energy density in most of Taiwan Island waters is above 3 kW/m, areas with relative high values are located in Keelung, Penghu, Hualian, surrounding waters of Dawu, especially Dawu waters, even up to 7.15 kW/m. Wave energy density in January and October is much larger than that in April and July. 2) Wave period in west waters of Taiwan Island is 4.5-5.5 s, about 6.0 s in east waters of Taiwan, Keelung waters and Eluanbi waters. 3) Frequency of effective SWH is large totally, and the frequency in January and October is much larger than that in April and July. 4) Wave energy storage around Taiwan Island waters is above 2×104 kWh·m-1. 5) Rich areas of wave energy around Taiwan Island waters are mainly located in Keelung waters, Hualian waters, Dawu area and Penghu waters, and indigent area is Kaohsiung waters.
Based on the precipitation data from 34 stations in Sichuan-Chongqing area and the monthly sea surface temperature (SST) reanalysis data of the NOAA/ESRL from 1960 to 2006, the relationship between the summer precipitation in the Sichuan-Chongqing region and SST of the Indian Ocean are studied by the methods of the empirical orthogonal function, point correlation, synthesis analysis and singular value decomposition analysis. The results of EOF for the summer standardized anomaly precipitation field shows that the first three modalities are steady and the first mode accounted for 27.8% of the total variance. The spatial distribution of precipitation presents the same type of the whole area. The analysis of point correlation shows that summer precipitation in the Sichuan-Chongqing region and the equatorial Indian Ocean region (10°N-16°S, 57-77°E) (hereinafter referred to as a key area) were significantly correlated. Synthetic analysis shows that when the SST of equatorial Indian Ocean anomalies was warmer (colder) than the normal, summer precipitation of the Sichuan-Chongqing region increased (decreased). SVD decomposition results show that summer precipitation in the Sichuan-Chongqing region and SST of the Indian Ocean was significantly correlated to the specific performance that SST of the Indian Ocean was in the same phase change with summer precipitation in eastern basin and western plateau of Sichuan Province, and the central basin was anti-phase change.
Taking the Yangtze River Delta as an example, this paper constructs an evaluation index system to assess the suitability of scenic spots location from the influencing factors. This valuation index system includes four aspects: the degree of relying on cities, the degree of dominance in transport nodes, the degree of supporting by society, and the degree of influence on existing scenic spots. Through analysis, we get some conclusions as follows. The degree of relying on cities presents a circle structure which takes prefecture-level cites as the center. The degree of dominance in transport nodes presents a circle structure which takes airports as the center. The degree of supporting by society presents a circle structure which takes Taihu Lake as the center. The high value regions of the degree of influence on existing scenic spots mainly distribute in the north of the Yangtze River Delta, and sporadically distribute in the south. As a whole, the degree of influence on existing scenic spots shows a pattern which is low in the internal and high in the external. The high value regions of suitability of scenic spots location mainly distribute in two regions: one is in the two banks of the Yangtze River Delta; the other is in the Hangzhou Bay coast. The low value regions mainly distribute in the outer Yangtze River Delta, especially in the south, southwest and Zhoushan Islands.
Rangeland on northern Tibetan Plateau is an important base for livestock production, and also plays a vital role in the ecological safety shelter zone in China. However, a series of ecological, economic and social problems were derived from the degradation of rangeland in the northern Tibetan which in return has not only directly threatened the ecological safety shelter zone in China and the animal husbandry production, but also resulted in negative effects on the regional sustainable development of rangeland ecosystem. Taking the Nagqu region in northern Tibet as a case, this study, applying complex ecosystem field theory, established an evaluation index system and models of rangeland sustainable development based on the ecological, productive and livelihood functions of rangeland ecosystem. The variation of sustainable development of rangeland ecosystem during 1985 to 2008 was analyzed, and sustainability was quantitatively evaluated in the Nagqu region of northern Tibet. The evaluation results showed that the development location of rangeland ecosystem exceeded its maximum carrying capacity, and that development potential, harmonious degree and the sustainable development degree of alpine rangeland ecosystem was very low, indicating that rangelands ecosystem was in an unsustainable development situation in the Nagqu region of northern Tibet.
Based on the element analysis of lacustrine sediments and surface soils in Chaiwopu Lake watershed, Xinjiang, the geochemical characteristics and potential ecological effects of the heavy metals are discussed with the methods of mathematical statistics. Associated with the principal component analysis (PCA) and correlation analysis of element contents from Chaiwopu Lake sediment core, the change of element content including Al, K, Na, Be, Ba, Ti, Ca, Mg and Sr was controlled by the regional chemical weathering intensity. The correlations are significant positive between the heavy metals (Fe, Mn, Zn, Cu, Cr, Ni, Pb and Cr), the organic matter content and the content of clay fraction. Before 1950 with the background of weak human activity, the heavy metals are controlled by the watershed hydrodynamics. In the period of last 50 years with strong human activities, the anthropogenic sources resulted in high loadings of heavy metals. With the constrained incremental sum of squares cluster analysis (CONISS) and cluster analysis of element contents of surface soils and lacustrine sediments, the geochemical composition characteristics were analyzed, which showed that the element contents recorded the impacts of human activity and natural environmental change. Finally, the potential ecological risk assessment of heavy metals (Cu, Cr, Zn and Pb) was evaluated. The results showed Cu and Pb were the more harmful heavy metal species in the studied areas, but the potential ecological risk of the whole heavy metals was slight.
The formulation of sampling unit size is essential in spatial sampling schemes for estimating crop sown area. Reasonable sampling unit size plays an important role for reducing sampling cost and improving population extrapolation accuracy. The experiment on optimizing sampling unit size was conducted to improve the efficiency of spatial sampling for winter wheat sown acreage estimation. Henan Province was selected as a study area and square grids as sampling units. Following the principle that sampled units are independent each other, sampling unit size is preliminarily selected through analyzing the relationships between different sampling unit sizes and corresponding global spatial autocorrelation index (Moran’s I) of all population units in the sampling frame. Furthermore, in order to find the optimal sampling unit size, eight kinds of sampling frames are constructed using the preliminarily selected sampling unit sizes and stratified sampling method. The stratification symbol is the ratio of winter wheat sown area accounting for that of a sampling unit, which is used to draw samples, and then extrapolate population value as well as estimate sampling errors. The experimental results demonstrate that, sampling fraction increases with the increase of sampling unit size; both the relative errors and coefficients of variation (CV) of population extrapolation are small at eight sampling unit size levels (relative errors vary from 3.82% to 5.75%, CV vary from 3.76% to 4.69%). It is found that the efficiency of stratified sampling method used to estimate the population of winter wheat sown area is the maximum, when the sampling unit size is 20000 m×20000 m.
The vegetation cover (VC) and corresponding vegetation canopy reflectance curves were collected in "Remotely sensed loading integrated testing site of non-driving aircraft (North testing site)"of Peking University, and the VC estimation models were developed and compared with each other based on the correlation between the conversion types (wavelet energy coefficient, principal component and vegetation index) of hyper-spectral curves and VC value. The result indicates: The hyper-spectral vegetation index-based model (R2>0.8, RMSE≤0.0188) is the best one of the three conversion types-based models, and EVI-based model is the best one among the other vegetation index-based models; the higher correlation coefficients existed between the second and the fourth single wavelet energy coefficient retrieved from 8-scale wavelet transformation and VC value (R2=0.811 and 0.813; RMSE=0.0199 and 0.0198, respectively); the multi-regression model established between multiple single wavelet energy coefficients and VC works better than the model based on the principal component analysis, the R2 and RMSE were improved by 0.058 and 0.03, respectively; the VC spatial distribution map through combining EVI-based model and TM-EVI indicates that the higher VC is distributed in the northern (75%) and southern (55%) parts of the study site and the lower VC (15%-55%) is distributed in the middle part. The spatial distribution is consistent with the land use/cover characteristics.
The paper built a dynamic simulation model of human-natural evolution by using dynamic model to have an empirical study on the law of human-natural system in Gannan based on the human-natural relationship, which described the potential situation of the evolution of human-natural relationship in Gannan and provided a theoretical basis for coordinating the human-natural relationship to change direction to sustainable development. The results indicate that the human-natural relationship of Gannan was in the maladjusted state and the human-natural system presents an unsustainable evolutionary trend in the future,economic development can only be lasted about 35 years. From the evolvement of the human-natural relation, according to the conditions of Gannan area, some ideas of optimizing the human-natural relationship are put forward. Accelerating the transformation of economic development is the inevitable choice to coordinate the Gannan’s human-natural relationship to move towards the sustainable development, reduce the dependence of economic growth on natural resources and the pressures on the environment can effectively delay the speed of exhaustion of resources, which has the positive impetus function to the human-natural system moving towards the sustainable development. Speeding up technical progress and increased environmental protection investment has a significant role to the coordination of the Gannan’s human-natural relationship. Gannan’s efforts to develop the economy must be accompanied by equally vigorous efforts to control the population, and improve its quality, which ultimately to coordinate the human-natural relationship of Gannan.
Carbon sequestration is research hot for addressing climate change and global system change. In this paper, combined with the concept of carbon sequestration and carbon sink, we make a comparative analysis on various carbon sequestration pathways for carbon dioxide capture and sealing, impact factor of carbon sequestration, and ecosystem service function. The results indicate that carbon sequestration by terrestrial ecosystem is the most safe and effective process; terrestrial ecosystem carbon sequestration impact on human and ecosystem health is less than geological and ocean carbon sequestration; ocean carbon sequestration easily leads to ocean acidification and irreversible damage to marine ecosystem; as it is difficult to predict the crustal movement, the geological carbon sequestration exist many unpredictable risks. Therefore, the utility of natural capacity of carbon sequestration by ecosystem and the development of green carbon sequestration technologies is the best choice to reduce the ecological risks of artificial carbon sequestration and CO2 emissions into the atmosphere.
