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The ecological environment in arid areas of Northwest China has undergone considerable changes under the combined effects of climate change and human factors. Therefore, exploring the spatial and temporal evolution of the ecological environment quality is of great significance for the protection and management of the ecological environment in arid areas of Northwest China. This study adopted Yuyang district as the study area. Landsat Thematic Mapper/Operational Land Imager images from 1993 to 2018 were selected as the data source for the retrieval of important surface indicators and the construction of the remote sensing distance ecological index. The spatial distribution, trend, and grade classification of the ecological environment quality were monitored and analyzed. The results showed that (1) the ecological environment quality of Yuyang district from 1993 to 2018 showed an overall upward trend, mainly manifested as a sharp decline in the area of poor ecological environment from 84.81 to 53.36%. (2) The spatiotemporal changes in the ecological environment quality showed a downward trend in the central urban area and an upward trend in the noncentral urban area. (3) In general, rainfall and temperature had limited impact on the ecological environment quality. Urbanization seriously affected the local ecological environment quality and the implementation of the ecological restoration policies, regulations, and measures were the main drivers of the improvement to the ecological environment quality in other surrounding areas.

Grasslands play an irreplaceable role in maintaining carbon balance and stabilizing the entire Earth’s ecosystem. Although the grasslands in Inner Mongolia are sensitive and vulnerable to climate change, a generalized effect of climate change on the grasslands is still unavailable. In this study, we analyzed the effects of annual mean precipitation and annual mean temperature on the normalized difference vegetation index from 1982 to 2010 on the Inner Mongolia Plateau. Our results indicated that the normalized difference vegetation index was mostly affected by precipitation, followed by temperature. Spatially, temperature and precipitation had greater effects on normalized difference vegetation index in dry regions than in wet ones. In time series, the effect of precipitation on normalized difference vegetation index had significantly decreased from 1982 to 2010 (R2 = 0.11, p > 0.05). However, the effect of temperature on normalized difference vegetation index remained stable. The high variation effect of precipitation on normalized difference vegetation index was due to the significant decrease in precipitation from 1980 to 2010. Thus, 35.47% and 0.56% of the dynamic of normalized difference vegetation index from 1982 to 2010 was accounted for by the precipitation and temperature, respectively. Our findings highlighted that grasslands are adaptable to the significant increase in temperature, but are sensitive to the decrease in precipitation on the Inner Mongolia Plateau.

Evapotranspiration (ET) plays a crucial role in hydrological and energy cycles, as well as in the assessments of water resources and irrigation demands. On a regional scale, particularly in the agro-pastoral ecotone, clarification of the distribution of surface ET and its influencing factors is critical for the rational use of water resources, restoration of the ecological environment, and protection of ecological water sources. The SEBAL model was used to invert the regional ET based on Landsat8 images in the agro-pastoral ecotone of northwest China. The results were indirectly verified by monitoring data from meteorological stations. The correlation between ET and surface parameters was analyzed. Thus, the main factors that affect the surface ET were identified. The results show that the SEBAL model determines an accurate inversion, with a correlation coefficient of 0.81 and an average root mean square error of 0.9 mm/d, which is highly suitable for research on water resources. The correlation coefficients of normalized vegetation index, surface temperature, land surface albedo, net radiation flux with daily ET were 0.5830, 0.8425, 0.3428 and 0.9111, respectively. The normalized vegetation index and the net radiation flux positively correlated with the daily ET, while the surface temperature and land surface albedo negatively correlated with the daily ET. The correlation from strong to weak is the net radiation flux > surface temperature > normalized vegetation index > surface albedo. In terms of spatial distribution, the daily ET of water was the highest, followed by woodland, wetland, cropland, built-up land, shrub land, grassland and bare land. However, the SEBAL model overestimates the inversion of daily ET of built-up land.

In order to implement the basic state policy of cherishing and rationally using land and strictly protecting cultivated land, effectively break the bottleneck of strategic resource development and urban development, optimize the land use structure, raise the level of economical and intensive land use, promote the balance between urban and rural areas and the sustainable economic and social development, and realize the overall development and protection of cultivated land. In the pilot project of reclamation and utilization of historical abandoned industrial and mining lands in Shenmu City, management requirements such as total control of resource utilization, two-way regulation of supply and demand and difference are implemented to standardize the reclamation and utilization behavior of abandoned industrial and mining lands. The waste residue covered by the mining area shall be stripped and cleared, the buildings and structures in the mining area shall be dismantled, and all the waste residue and construction waste shall be transported to the designated accumulation point. Then, as needed, it will be cleared into farmland, forests, grasslands and rivers. Results: The reclamation area of the project covers 42 plots, with a total area of 2146.4 mu. The construction scale of the project is 124.8122hm2. Through the reclamation of abandoned industrial and mining land, 22.1038hm2 of new cultivated land was added in the project area, with a rate of 17.71%. The new grassland area was 32.2119hm2. After reclamation, the land utilization rate of the project increased significantly, reaching 93.38%. It promotes the balance of dynamic indexes of cultivated land in Shenmu City, maintains the dynamic balance of total cultivated land in Shaanxi Province, and improves the production and living conditions of local farmers. The project has great ecological benefit, obvious social benefit and certain economic benefit. The unification of social benefit, economic benefit and ecological benefit is realized, which accords with the goal of industrial waste land reclamation.