It is difficult to estimate the effects of vegetation on dust-storm intensity (DSI) since land surface data are often recorded aerially while DSI is recorded as point data by weather stations. Based on combining both types of data, this paper analyzed the relationship between vegetation and DSI, using a panel data-analysis method that examined six years of data from 186 observation stations in China. The multiple regression results showed that the relationship between changes in vegetation and variance in DSI became weaker from the sub-humid temperate zone (SHTZ) to dry temperate zone (DTZ), as the average normalized difference vegetation index decreased in the four zones in the study area. In the SHTZ and DTZ zones, the regression model could account for approximately 24.9% and 8.6% of the DSI variance, respectively. Lastly, this study provides some policy implications for combating dust storms.
Based on the synergetic development of new industrialization, rapid urbanization and agricultural modernization (IUAM), and from the viewpoint of interactive relationships between water resources and regional population, eco-environment, economy and society, the concepts of water resources intensity (WRI), water environment intensity (WEI), water resources relative efficiency (WRRE) and water environment relative efficiency (WERE) are defined with reference to energy intensity, resources efficiency and environment efficiency theory. On the basis of benchmarking theory, the quantitative characterization and evaluation method of “Three Red Lines” (the upper limit of water resources allocation, the baseline of utilization efficiency of water resources and the upper limit of sewage discharge) is proposed. According to these concepts and models, an empirical analysis of the Three Red Lines of water resources on the Chinese mainland between 2003 and 2012 was carried out. The results showed that total water consumption in eastern, central and western parts of China possesses “club convergence” characteristics, which means these areas have similar internal conditions appeared convergence in the development. Inter-provincial differences in water consumption continue to decrease, but the north-south differentiation characteristics in the eastern and central regions were still relatively obvious, while provincial differences in the eastern part were at a minimum and the central region had the largest. Water Resources Efficiency (WRE) of all four sectors in the Southwest rivers and Huaihe River basins were generally high. Industrial WRRE in the Songhua River, Yangtze River and Pearl River basins, agricultural WRRE in the Songhua River, Yellow River and northwestern river basins and domestic WRRE in the Liaohe River, Yangtze River and Pearl River basins were all low. Eco-environmental WRRE in the southeastern rivers and Yangtze River basins were low but showed an upward trend. Other river basins, except for the Northwestern rivers basin, had high eco-environmental WRRE with a downward trend. Western China, especially the northwestern part, had a low relative intensity of the water environment (WERI) and high integrated water environment management (IWEM) performance, but the relative intensities of the water resources (WRRI) were fairly high, and the comprehensive performance of integrated water resources management (IWRM) in these regions was low. In southern China, especially the southeastern part, the IWEM was fairly high, but the overall IWRM was lower.
Inland lakes and alpine glaciers are important water resources on the Tibetan Plateau. Understanding their variation is crucial for accurate evaluation and prediction of changes in water supply and for retrieval and analysis of climatic information. Data from previous research on 35 alpine lakes on the Tibetan Plateau were used to investigate changes in lake water level and area. In terms of temporal changes, the area of the 35 alpine lakes could be divided into five groups: rising, falling-rising, rising-falling, fluctuating, and falling. In terms of spatial changes, the area of alpine lakes in the Himalayan Mountains, the Karakoram Mountains, and the Qaidam Basin tended to decrease; the area of lakes in the Naqu region and the Kunlun Mountains increased; and the area of lakes in the Hoh Xil region and Qilian Mountains fluctuated. Changes in lake water level and area were correlated with regional changes in climate. Reasons for changes in these lakes on the Tibetan Plateau were analyzed, including precipitation and evaporation from meteorological data, glacier meltwater from the Chinese glacier inventories. Several key problems, e.g. challenges of monitoring water balance, limitations to glacial area detection, uncertainties in detecting lake water-level variations and variable region boundaries of lake change types on the Tibetan Plateau were discussed. This research has most indicative significance to regional climate change.
The Pearl River Delta on China’s coast is a region that is seriously threatened by sea level rise and storm surges induced by global climate change, which causes flooding of large areas of farmland and huge agricultural losses. Based on relevant research and experience, a loss evaluation model of farmland yield caused by sea level rise and storm surges was established. In this model, the area of submerged farmland, area of crops, and per unit yield of every type of crop were considered, but the impact of wind, flooding time, changes in land use and plant structure were not considered for long-term prediction. Taking the Pearl River Delta region in Guangdong as the study area, we estimated and analyzed the spatial distribution and loss of farmlands for different scenarios in the years 2030, 2050, and 2100, using a digital elevation model, land-use data, local crop structure, rotation patterns, and yield loss ratios for different submerged heights obtained from field survey and questionnaires. The results show that the proportion of submerged farmlands and losses of agricultural production in the Pearl River Delta region will increase gradually from 2030 to 2100. Yangjiang, Foshan, and Dongguan show obvious increases in submerged farmlands, while Guangzhou and Zhuhai show slow increases. In agricultural losses, vegetables would sustain the largest loss of production, followed by rice and peanuts. The greatest loss of rice crops would occur in Jiangmen, and the loss of vegetable crops would be high in Shanwei and Jiangmen. Although losses of peanut crops are generally lower, Jiangmen, Guangzhou, and Shanwei would experience relatively high losses. Finally, some measures to defend against storm surges are suggested, such as building sea walls and gates in Jiangmen, Huizhou, and Shanwei, enforcing ecological protection to reduce destruction from storm surges, and strengthening disaster warning systems.
The capacity of soil and water conservation measures, defined as the maximum quantity of suitable soil and water conservation measures contained in a region, were determined for the Loess Plateau based on zones suitable for establishing terraced fields, forestland and grassland with the support of geographic information system (GIS) software. The minimum possible soil erosion modulus and actual soil erosion modulus in 2010 were calculated using the revised universal soil loss equation (RUSLE), and the ratio of the minimum possible soil erosion modulus under the capacity of soil and water conservation measures to the actual soil erosion modulus was defined as the soil erosion control degree. The control potential of soil erosion and water loss in the Loess Plateau was studied using this concept. Results showed that the actual soil erosion modulus was 3355 t?km-2?a-1, the minimum possible soil erosion modulus was 1921 t?km-2?a-1, and the soil erosion control degree was 0.57 (medium level) in the Loess Plateau in 2010. In terms of zoning, the control degree was relatively high in the river valley-plain area, soil-rocky mountainous area, and windy-sandy area, but relatively low in the soil-rocky hilly-forested area, hilly-gully area and plateau-gully area. The rate of erosion areas with a soil erosion modulus of less than 1000 t?km-2?a-1 increased from 50.48% to 57.71%, forest and grass coverage rose from 56.74% to 69.15%, rate of terraced fields increased from 4.36% to 19.03%, and per capita grain available rose from 418 kg?a-1 to 459 kg?a-1 under the capacity of soil and water conservation measures compared with actual conditions. These research results are of some guiding significance for soil and water loss control in the Loess Plateau.
Wind erosion is a major contributor to land degradation and desertification. According to the Global Assessment of Human Induced Soil Degradation, the dryland territories of Mongolia are significantly affected by wind erosion. We used the wind erosion equation model in an ArcGIS environment to evaluate wind erosion across Mongolia. The individual factors of the wind erosion equation were parameterized using the following datasets: (a) monthly climatic data from 45 meteorological stations; (b) 16-day composites of MODIS Normalized Difference Vegetation Index data; (c) a SRTM DEM with a 90 m spatial resolution; and (d) the soil map of Mongolia. The results revealed the significant influence of aridity on wind erosion. The desert and semi-desert ecosystems were more vulnerable to wind erosion, hence more affected. The map of wind erosion revealed three major wind erosion regions where the maximum soil loss of 15-27 t/(hm2?a) was observed. In general, the wind erosion potentials for the entire country of Mongolia are 15-27 t/(hm2?a) in the deserts and semi-deserts, 10-15 t/(hm2?a) in the dry steppes and 5-10 t/(hm2?a) in the steppe regions.
Although there has been rapid rural-urban migration in rural China since the 1980s, the total grain production of China saw a continuous increase. As of today, the relationship between labor migration and grain output growth remains partial and contradictory. The main aim of this empirical study is to examine some specific measures adopted by peasants to deal with labor shortage and maintain grain output growth. Using tracking survey, participatory rural appraisal methods, and land plot investigation, we investigate 274 households and 1405 arable land plots in four villages in two stages in Jinchuan county, southwestern China. The results show that continuous emigration of labor from the four villages caused the abandonment of a small amount of land, decreased labor intensity, and reduced multiple cropping index, shifting from “corn-wheat” multiple cropping pattern to the “corn” cropping pattern, which means labor shortage in some households. At the same time, owing to surplus labor in the villages, the peasants utilize a series of means to offset the negative impacts of labor migration on grain output, such as cropland transfer, labor exchange in the busy seasons, and the substitution of capital and technology for labor. The econometric analysis also shows that labor migration boosts grain production. This study provides a reasonable explanation of grain output growth under rural-urban migration.
The development of grass-feeding livestock breeding is the key to promoting the transition from grain-consumption type animal husbandry to grain-saving type animal husbandry in China, and to solving the problem of competition for grain between people and livestock. From the perspective of economic geography, this paper first defines the conversion standard for the breeding quantity of livestock, and then uses exploratory spatial data analysis technology and econometric models and methods to systematically investigate the sequential variation process, geographical aggregation characteristics, and influencing factors of grass-feeding livestock breeding in China. The study results show the following: 1) The breeding quantity of grass-feeding livestock in China has an obvious overall growth trend, but there is an obvious difference among the livestock species. During the period 1978-2012, the breeding quantity of grass-feeding livestock in China grew by 92.5%; and the breeding quantity within the same period was beef cattle > sheep > dairy cow. 2) On the county scale, the number of increasing areas of the breeding quantity of grass-feeding livestock is larger than the number of decreasing areas, and the growth rate of breeding quantity of grass-feeding livestock in northern China is higher than that in southern China, which initially forms the pattern of “hot in the north and cold in the south”. 3) The spatial Durbin model shows that the per capita output of grain, proportion of productive land area, urban per capita disposable income, agricultural mechanization level, agricultural labor productivity and policy factor have positive effects on the development of grass-feeding livestock breeding, while the per capita GDP, urbanization level and proportion of non-agricultural income have obvious negative effects on it. 4) Grass-feeding livestock breeding in China can be divided into six major types of areas, and each type of area should be regulated and controlled in terms of their respective focus of attention according to regional conditions and situation of agricultural production.