Improving energy efficiency is one of the important ways to solve the energy problem. This paper analyzes trajectories and geographies of energy efficiency in China. More specifically it examines the evolution and regional differences in 1990, 2000 and 2010 through the DEA model of the Total Factor Energy Efficiency (TFEE). And using the Exploratory Spatial Data Analysis (ESDA), the paper then discusses its spatial agglomeration as well as the cold and hot spots, and draws the following conclusions. 1) There is a substantial difference in the energy efficiency among provinces in China, with higher energy efficiency in the eastern region and lower in the western region. 2) Different factors contribute to the difference in energy efficiency among provinces in China. Generally speaking, the provinces can be divided into four main kinds which are energy input slack, human capital input slack, capital input slack as well as energy and human capital input slack. With the rapid growth of China's economy, energy input and human capital input are the most popular factors leading to low efficiency. 3) Spatial autocorrelation analysis demonstrates that there is significant agglomeration of energy efficiency, pure technical efficiency and scale efficiency amongst Chinese provinces. 4) The cold and hot spots in terms of energy efficiency in China have shown regional differences from coastal to inland, and gradual decline from east region to central and west regions. Viewed from the decomposition of energy efficiency, the spatial structure and evolution of energy efficiency and pure technical efficiency are basically identical, while the scale efficiency showed significant difference.
The purpose of this study is to assess the agricultural water utilization in irrigated farmland of China based on water footprint of grain production evaluation. Having collected the data of 459 irrigation districts in 1998, 2005 and 2010, this paper calculates the grain production water footprint (GPWF) in irrigated farmland of China from a regional scale, and it then analyzes the relationship between grain production and agricultural water use by establishing an integrated water-grain rationality assessing indicator (I). The analyzed result shows that GPWF in Northeast and South China is high, while the low values are located around Huang- Huai-Hai Plain. GPWF in the regions of Hainan, Jilin, Liaoning and Heilongjiang exceed 2.400 m3/kg, while no more than 1.000 m3/kg in other six provinces, including Beijing, Shandong, Henan, Shanxi, Shaanxi and Hebei. The national value of GPWF during the study period is 1.336 m3/kg and the shares of blue and green water footprint are 64.1% and 35.9% respectively, and about 35.1% of the water footprint is not used for the crop evapotranspiration (ET). Same with the GPWF, the spatial difference of blue and green water footprint composition is big. Proportion of green water in GPWF as a whole (RG) in Hubei is 58.5%, ranking the highest of all the 31 provinces of China. The RG in Zhejiang, Shandong, Henan and Sichuan is also above 50.0%. RG in other 13 provinces is below the national value and no more than 20.0% in Jilin, Ningxia and Xinjiang. Spatial autocorrelation analysis results show that provinces with resembling water productivity values demonstrate significant aggregation. Local autocorrelation analysis reveals that more than 20 provinces show high- high positive autocorrelation (HH) or low- low positive autocorrelation (LL). General and regional spatial differentiation characteristics among the selected years are insignificant. The value of I is significantly different among provinces, which fluctuates between 0.114 and 0.850 and the variation coefficient is 0.55. Water use in regions located in the middle and lower reaches of the Yellow River is rational while the situation is the opposite for most areas of Northeast and Northwest China. The index I could explain the differences of relationships between grain production and water use in different regions. The 31 provinces are divided into four categories according to the parameters of agriculture water utilization and grain production capability, and the policies in resources management and food security safeguarding of all categories are discussed in this paper. Water footprint and water utilization in some regions could be improved significantly, especially the provinces in Northeast and Northwest China.
Based on the Theil index and an econometric model, this paper analyzed the spatiotemporal difference and driving forces of six input factors intensity of arable land-use in China. The results showed that: 1) At the national scale, the labor intensity of arable land-use has decreased, while the remaining five input factors intensity showed a rising trend in China, and among them, agricultural fixed assets being of the highest growth rate. 2) At the regional scale, the temporal pattern of six input factors intensity for arable land- use was in common with which at the national scale. In addition to the labor intensity which the central region was of the highest value, intensity of other five input factors were of the highest values in the eastern region, the central region took the second place and the northeast and west regions were of the lowest values. 3) At provincial scale, there was two changing directions in labor intensity, while the intensity of fertilizer, pesticide and agricultural diesel oil decreased in Shanghai, Tianjin, Jiangsu and Shandong where are economically developed. 4) The regional differences of six input factors intensity of arable land- use in China was evident and showed a narrowing trend. The differences of six input factors intensity of arable land-use between four major regions contributed more than differences within the region. 5) Per capita annual net incomes of household operations and proportion of nonagricultural population had a significant positive correlation with inputs of fertilizer, agricultural investment in fixed assets, pesticide and agricultural plastic film. The proportion of nonagricultural industry had a significant positive correlation with fertilizer input. Agricultural policies promoted the inputs of fertilizer and agricultural investment in fixed assets. Finally, we suggest that there is an urgent need to focus on the structure of agricultural investment in fixed assets and its social, economic and ecological effects, as well as ecological impact of heavy application of fertilizer, pesticide and agricultural plastic film. In order to comprehensively promote the arable land- use intensity under the conditions of area constraints, the government should focus on improving per capita annual net incomes of household operations, meanwhile strengthening the agricultural support policies for less developed regions and major grain producing regions.
Land-use change is a major driver behind the loss of ecosystem services. In recent years, a great emphasis has been placed on the responsiveness of ecosystem services value to the land-use change, and the coefficient of sensitivity, as an important indicator, has been widely used for the assessment of this responsiveness. However, the limitation of sensitivity analysis, proposed by Kreuter et al, on this application has been neglected. In this paper, firstly, the reexamination was carried out for the conventional sensitivity analysis, and the concept of cross-sensitivity and its calculation was proposed on this basis, through which it was more intuitive to characterize the responsiveness of ecosystem services value to the mutual transformation between land use types. Secondly, a dynamic analysis was conducted using coefficient of cross- sensitivity for the responsiveness of ecosystem services value to the transformation among land use types in the Keriya Oasis in 1991, 2002 and 2011 respectively, noting the processes of land-use change, to which ecosystem services were increasingly sensitive, to provide a reference for land-use policy. The main conclusions were drawn as follows: 1) The categories of land-use transformations to which the ecosystem services showed sensitive were stable during the three time points 1991, 2002 and 2011, mainly concentrated on the conversions from the land-use types with high ecosystem functionality, i.e. wetland and water body, to the others which are large in size and poor in ecosystem service provision, i.e. desert and low- densitygrass. For example, 1% conversion from wetland to desert caused 4.15% loss in ecosystem service in 1991, and 4.45% loss in 2002; 1% transformation from water body to low-density-grass led to 1.16% and 1.30% loss in ecosystem service in 1991 and 2002. 2) As compared with 1991 and 2011, the cross-sensitivity coefficients generally increased in 2002, mainly due to the decrease in the size of wetlands and water area which exacerbated the ecological vulnerability of the study area, and as a result the value of ecosystem services showed greater sensitivity to such transformations. 3) The coefficient of cross- sensitivity for the transformation from wetlands and water body to arable land had been in a rising trend, and continued close to -1, indicating that the value of ecosystem services became more and more sensitive to the intensifying human activities.
The groundwater renewal ability is the basis for the rational development and utilization of groundwater resources, as well as the important factor to the grain production in Sanjiang Plain. The analyses of the shallow groundwater ages were conducted to study the recharge source of the groundwater and the renewable ability during 10th-17th, September 2009. There are 11 shallow groundwater samples were collected from the less than 60 m deep wells along Heilongjiang River, Songhua River and Wusuli River. The shallow groundwater samples were analyzed for concentrations of tritium (T) and chlorofluorocarbons (CFCs) by Quantulus 1220 and GC-ECD, respectively. The groundwater ages were calculated by the tritium and CFCs contents with piston flow model, respectively. The results show that the tritium content in shallow groundwater ranged from 1.7-61.2 TU. While, the CFC-12 and CFC-113 concentrations ranged from 0.04-1.25 pmol·kg-1 and 0.1-0.71 pmol·kg-1, respectively. The shallow groundwater age ranged from 39-51 years according to the contents of tritium. Meanwhile, the CFC-12 apparent groundwater age ranged from 38.2-61.7 years. The shallow groundwater with age less than 39 years was missing according to the tritium and CFCs data, indicating that the groundwater mainly recharged from the allogenic water in Sanjiang Plain. The percolating water from the water deep circulation recharges the surface water, forms to the wetland, and discharges to river finally. The groundwater table monitoring data shows that the groundwater table was the least in June since the agricultural irrigation. However, the groundwater table increased to the elevation before irrigation in September. The groundwater renewable ability also shows that there is stable recharge source in Sanjiang Plain. Consequently, the groundwater could be explored and utilized appropriately to increase the farmland, and to enhance the sustainable agricultural development in Sanjiang Plain.
The cognition and awareness of water deficit which is computed as the difference between precipitation and potential evaporation has an important role to understand the supplydemand situation and rational utilization of water resources. Based on the daily precipitation, mean temperature, maximum and minimum temperature, wind speed, sunshine hours, average related humidity data of 27 meteorological stations in the Hengduan Mountains region during the period of 1961-2012 and using the methods of climate tendency rate, Penman- Monteith model, Inverse Distance Weighted interpolation, the temporal-spatial variations of water deficit and the relationship between the water deficit and PDO, AO and ENSO by the cross wavelet and wavelet coherence techniques were analyzed in terms of summer monsoon in the Hengduan Mountains region. The results are as follows: 1) The annual mean value of water deficit changed and increased obviously in fluctuation and the increasing rate was 5.87 mm/10 a in the summer monsoon during the recent 52 years. The amount of water deficit was positive in the summer monsoon over the study area. 2) The mean value of water deficit existed obvious differences in the space and presented decreasing trends from south to north. However, the changing trends increased gradually from south to north. The water deficit had increasing trends at rate of 7.96 mm/10 a, 7.54 mm/10 a and 2.16 mm/10 a in the northern, central and southern over the study area, respectively. 3) The relationship between the water deficit and elevation indicated that precipitation extreme events decreased with the altitude. Furthermore, the relationship between the water deficit and PDO, AO and ENSO presented significant periodic variations with water deficit. In general, the increase of water deficit will relieve the contradiction between water supply and demand, decrease climate drought and improve ecological environment in the Hengduan Mountains region.
The sustainable resources use is the core of development and its main component. As the background of the "nature-economy-society" trinity complex system, this paper, based on the perspective of the comprehensive resources utilization efficiency, put forward Resources Welfare Index (RWI) with the combination of Human Development Index (HDI) and Ecological Footprint Index (EFI). RWI means the level of welfare brought about by the unit resource to fully reflect the comprehensive efficiency level of the resources utilization to develop economy at the same time feedback to society. This paper used 24 countries as the research sample including the G20 countries and analyzed the changes of HDI, EFI and RWI from 1996 to 2008 to evaluate sustainable situation of resources utilization. We concluded that the sustainable utilization of the resources of the 24 countries could be roughly divided into three categories. The first category, benign development, the growth rate of RWI was positive, social welfare improved and resource consumption reduced; the second category, inferior benign positive development, the growth rate of RWI was positive, social welfare and resource consumption both improved, but the former growth rate is higher than the latter, and the third category, inferior malignant positive development, the growth rate of RWI was negative, social welfare and resource consumption both improved, but the former growth rate is lower than the latter.
There are various types of ecosystems and complex landform in alpine area of southwest China, which make it an ideal place to research regional response to global changes in climate. A process-based biogeochemical model CEVSA (Carbon Exchange between Vegetation, Soil, and the Atmosphere) was used to estimate temporal and spatial variations of soil organic carbon (SOC) in alpine area of southwest China during 1954-2010. The results showed: 1) The mean values of SOC density were 14.16 kg C·m-2 during1954-2010 in alpine area of southwest China. In spatial distribution, SOC density increased from southeast to northwest and was significantly negatively correlated with annual mean temperature(r=-0.447, P<0.01), but had no significant correlation with annual total precipitation. 2) Total SOC storage ranged from 6.95 to 7.64 Pg C and showed a statistically significant increasing trend with a growth rate of 0.013 Pg C (P<0.05) during 1954-2010. 3) The increasing trend of SOC density was highly significant (P<0.01) in herbaceous cover (closed-open), evergreen needle-leaved tree cover and evergreen broad-leaved tree cover which was the three main vegetation types. SOC density of herbaceous cover (closed- open) and evergreen needle- leaved tree cover in the study area were both correlated positively with annual mean temperature (r=0.527, P<0.01; r=0.501, P<0.01) but SOC density of evergreen broad-leaved tree cover had no correlation with annual mean temperature. There were no significant correlation between SOC density and annual total precipitation in all of the three vegetation types. 4) The growth of soil organic carbon (SOC) storage may slow down or reverse by ongoing climate change, for that HR was more sensitive to temperature than LT which acted as the carbon input of soil ecosystem.
During the 1950s and 1960s, the forest had been greatly reduced and degraded, as a long-term over-logging on a large scale, and then, there were many different patterns of plantations and secondary forest. In this paper, in order to assess the effect of land use change on soil organic carbon (SOC) and soil microbial biomass carbon (SMBC), soil samples were taken from primeval Abies spp. forest, Picea spp. forest, Picea spp.+ Betula albo-sinensis mixed forest, shrub forest, converted cropland to Picea spp. forest, grassland, at the same time, slope farmland was set as CK, and their SOC, SMBC contents of different seasons in soil surface (0- 15 cm) and subsurface (15-30 cm) were determined. The results showed that the contents of SOC and SMBC in soil surface were significantly higher than subsurface (P<0.05) under each land use pattern; the content of SOC was the highest in winter, the second highest in summer, the lowest in autumn, but the dynamics of SMBC were opposite to the varies of SOC. The effect of land use on SOC and SMBC contents were very significant, the contents of SOC and SMBC under CK were the lowest in each season. In soil surface, the annual mean content of SOC under CK was only 23.55%, 29.44%, 33.12%, 43.94%, 58.13% and 67.63% of primeval Abies spp. forest, shrub forest, grassland, Picea spp.+ Betula albo-sinensis mixed forest, converted cropland to Picea spp. forest and Picea spp. forest, in soil subsurface the percentages were 18.02%, 27.30%, 32.93%, 40.74%, 55.26% and 58.10%; and the annual mean content of SMBC under CK was only 20.50%, 23.23%, 30.63%, 36.48%, 46.22% and 59.07% of primeval Abies spp. forest, shrub forest, grassland, Picea spp. forest, Picea spp.+ Betula albo-sinensis mixed forest and converted cropland to Picea spp. forest, in soil subsurface the percentages were 25.66%, 35.65%, 40.23%, 43.63%, 55.34% and 66.71%. With the effect of land use, the seasonal dynamics of qSMB were the same as the SMBC content and the opposite to the SOC content, but the order were not obvious.
In this paper, Total Organic Carbon (TOC) content of surficial sediments and its temporal and spatial distribution in Yancheng coastal wetland were comparatively investigated, which was aimed to explore the effects of different seasons, vegetation coverage and soil characteristics on the TOC in coastal wetland. The result indicated that TOC ranged from 0.69 to 10.34 g/kg, with an average of 4.55 g/kg. The seasonal characteristics of TOC showed that the peak of TOC in the entire flats appeared in winter, that is the non-growing season of vegetation, except for the mud flat, the highest TOC turned out to be in autumn (0.86±0.11 g/kg), the seasonal variations of TOC differed significantly in Artemisia schrenkiana flat (0.565) which was influenced by the presence and growth stages of vegetations. For the spatial changes of TOC, it exhibited a tendency that Spartina alterniflora flat (10.34 ± 2.42 g/kg) >Phragmites australis flat (3.90±1.11 g/kg) >Artemisia schrenkiana flat (3.28±1.86 g/kg) > mud flat (0.69±0.16 g/kg). TOC showed significant spatial heterogeneity, with the minimum value appeared in mud flat (0.06) and maximum was observed in Phragmites australis flat (0.14). What's more, surficial sedments TOC content has significant correlation with total nitrogen (TN), water- filled pore space (WFPS), mean grain size, sorting coefficient and C/N ratio. This study shows that the invasion of exotic species, such as Spartina alterniflora might effectively enhance soil carbon sequestration potential of the coastal wetlands ecosystem due to its higher enrichment capability of organic carbon and greater biomass compared to thoses of other vegetation types. The main reason of high correlation between TOC and TN is that they have the same way of source and consumption, while, WPFS, mean grain size and C/N play an important role in determining TOC content through affecting microorganism activity.
This article, using the computational model of sunshine duration based on DEM in rugged terrains and taking Guangxi Bama County as the example, with the aid of GIS technology, modeled the of monthly sunshine duration and validated the result. Validation determined that the simulated data were in agreement with the measured data from the meteorological station, with a determined coefficient of 0.996. Discussing the characteristics of spatial and temporal distribution of sunshine duration in karst area, it explored the change rules of sunshine duration in different time scales and analyzed the influence of terrain factors such as slope, aspect, relief degree of land surface and surface roughness etc. to sunshine duration. This method could provide essential data of climate, which is significant to the analysis of microclimate and agricultural climate resources distribution in karst area.
