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Soil wind erosion is the main cause of land degradation in arid and semi-arid areas in northern China, which is mainly affected by surface type, climate and so on. Strong soil wind-erosion will not only accelerate regional desertification and influence the quality of human life, but also cause serious ecological and environmental problems. Since the 2000 s, our country has gradually strengthened the control of land desertification and carried out a series of sand control works, which effectively improved the overall ecological environment of the sandy land. But in recent years, there are some common phenomenon that extensive grassland and brushland was turned into cultivated land in the southeast and southwest of Mu Us sandy land. However, in the dry and windy winter or spring, these new reclaimation land is usually so exposed that it is vulnerable to suffer from strong wind erosion. Therefore, it is great significance to study the characteristics of soil wind erosion in new reclaimation land and find out the control methods. Based on the above question, this paper selected the southern part of Mu Us sandy land (38°05′27″-38°13′58″N, 107°24′28″-107°37′30″E) as the research area, as well as set up 5 observation points on different surfaces, which were represented respectively by A, B, C, D and E. Point A was on the brushland, point B was on the middle of the grassland, and other three points were respectively on different parts of the cultivated land. On the day with strong wind activity, 12 groups simultaneous observation of wind and sand were made at these 5 points (A, B, C, D, E), with each observation time at least 20 minutes. After these observations, the material of the sand samplers were weighed with an electronic balance of 1/1 000, and the material of surface and sand samplers on cultivated land were analyzed by Mastersizer2000 Laser Particle Size Analyzer. The results showed that the soil wind erosion intensity increased exponentially after grassland and shrubland were cultivated; on cultivated land, with the increase of height, the sediment transport rate decreases with exponential function within 0-10 cm height and power function within 10-20 cm height. Due to the height of the sand collector used in this paper is 20cm, lower than the height of the sand flow layer. In order to obtain the total sediment transport rate of the surface of the cultivated land, this paper must calculate it through the function simulation obtained from the above result. After calculating the total sediment transport rate, fitting it with the wind speed. We found that the total sediment transport rate has a good power function relationship with the wind speed in the cultivated land with sufficient erodibility particles. Based on the formula of the relationship between wind speed and total sediment transport rate, as well as the wind speed data of the meteorological stations in the region, the wind erosion modulus of the new reclaimation land can be preliminarily calculated. The result shows that the wind erosion modulus of the new reclaimed land is 9 657 t/(km2·a). Through the results obtained in this paper, combined with the former research results, this paper argues that the emergence of new reclaimed land has an important impact on regional desertification, and its area should be used as an important index when evaluating regional desertification. Meanwhile, Controlling cultivated land area, establishing windbreak and sand fixation forest, as well as retaining stubble at a certain height can effectively control soil wind erosion in newly reclaimed land. [ABSTRACT FROM AUTHOR]

Drought is a natural hazard caused by long-term precipitation deficiency and high evaporation resulted from high temperature, which is among the most common disasters around the world. In recent decades, with the intensification of climate change and human activities, drought occurrence is becoming more frequent in China, causing negative impacts on agricultural production, ecological environment and social economy. Therefore, it is significant to explore the impact of drought on vegetation for agricultural production and healthy development of ecological systems. In this paper, the response and sensitivity of vegetation to drought in different climatic zones in China were analyzed, and the effects of different climatic factors, including water balance (precipitation-potential evapotranspiration), annual precipitation, mean temperature and sunshine hours, on the relationship between different vegetation types including forestland, grassland and cultivated land and drought were explored, so as to reveal the response mechanism of ecological vegetation to drought from a macro perspective. Using the self-calibrating Palmer drought severity index (scPDSI) and normalized difference vegetation index (NDVI) data for the period of 1982-2015, the response rule and sensitivity of different types of vegetation to drought were analyzed by applying time-delay correlation method, and the influence of various climate factors on the relationship between vegetation and drought was analyzed by applying linear regression method. The results of the research showed that in northwest China, Inner Mongolia, north China plain and southern Qinghai-Tibet plateau, the correlation of shorter lag time scPDSI (1-3 months) and NDVI was close (Rmax>0.4), which indicated that vegetation growth was more sensitive to drought in these regions and that vegetation biomass were influenced mainly by the spatiotemporal characteristics of the water availability. In the humid areas of south China, including the middle and lower reaches of the Yangtze River and the Pearl River basin, the precipitation is abundant so that the correlation between NDVI and scPDSI was negative, and the response of vegetation was not sensitive to drought. The growth of vegetation is mainly controlled by energy factors such as temperature and sunshine hours. The relationship between vegetation and drought was significantly affected by the average annual water balance, precipitation, sunshine hours and temperature, among which the annual water balance was the main water controlling factor (R²=0.45). It can be concluded that the change of water availability was the key factor behind the change of vegetation vigor. Sunshine hours were the main energy controlling factor. When average annual temperature was less than 5, the effect of ℃ temperature on the correlation between scPDSI and NDVI was also significant. The sensitive areas of drought impact on vegetation were mainly in the northern arid regions, while the southern humid areas had strong resilience and resilience to drought. The sensitivity of different types of vegetation to drought varied greatly, and the order of sensitivity is grassland >forestland>cultivated land. The results can provide a scientific basis for the evaluation of the impact of drought on ecological vegetation in different regions of China, and thus help to guide agricultural and environmental production, protect vulnerable ecosystems and provide implications for sustainable socioeconomic development. [ABSTRACT FROM AUTHOR]