A large-scale re-vegetation supported by the Grain for Green Project (GGP) has greatly changed local eco-hydrological systems, with an impact on soil moisture conditions for the Chinese Loess Plateau. It is important to know how, exactly, re-vegetation influences soil moisture conditions, which not only crucially constrain growth and distribution of vegetation, and hence, further re-vegetation, but also determine the degree of soil desiccation and, thus, erosion risk in the region. In this study, three eco-environmental factors, which are Soil Water Index (SWI), the Normalized Difference Vegetation Index (NDVI), and precipitation, were used to investigate the response of soil moisture in the one-meter layer of top soil to the re-vegetation during the GGP. SWI was estimated based on the backscatter coefficient produced by the European Remote Sensing Satellite (ERS-1/2) and Meteorological Operational satellite program (MetOp), while NDVI was derived from SPOT imageries. Two separate periods, which are 1998–2000 and 2008–2010, were selected to examine the spatiotemporal pattern of the chosen eco-environmental factors. It has been shown that the amount of precipitation in 1998–2000 was close to that of 2008–2010 (the difference being 13.10 mm). From 1998–2000 to 2008–2010, the average annual NDVI increased for 80.99%, while the SWI decreased for 72.64% of the area on the Loess Plateau. The average NDVI over the Loess Plateau increased rapidly by 17.76% after the 10-year GGP project. However, the average SWI decreased by 4.37% for two-thirds of the area. More specifically, 57.65% of the area on the Loess Plateau experienced an increased NDVI and decreased SWI, 23.34% of the area had an increased NDVI and SWI. NDVI and SWI decreased simultaneously for 14.99% of the area, and the decreased NDVI and increased SWI occurred at the same time for 4.02% of the area. These results indicate that re-vegetation, human activities, and climate change have impacts on soil moisture. However, re-vegetation, which consumes a large quantity of soil water, may be the major factor for soil moisture change in most areas of the Loess Plateau. It is, therefore, suggested that Soil Moisture Content (SMC) should be kept in mind when carrying out re-vegetation in China’s arid and semi-arid regions.

With the random discharging of industrial and agricultural wastewater, a large amount of cadmium (Cd) has accumulated in the soil, which seriously affects the growth of crops and people’s food safety. In this study, alfalfa was used as the material for studying the effects of the inoculation of Piriformospora indica (P. indica) on photosynthesis, osmoregulatory substances, and antioxidant enzymes of alfalfa seedlings at different Cd concentrations (0, 5, 10, 30, 50, and 100 mg/L) through hydroponic experiments. The results showed that with the increase in Cd concentration, the chlorophyll content, net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) of alfalfa all decreased gradually, while the intercellular CO₂ concentration (Ci) decreased at first and then increased. However, compared with non-inoculated control plants, the inoculation of P. indica improved the photosynthesis (41.97%) of alfalfa under Cd stress, increased the chlorophyll content (43.70%), and significantly increased the contents of proline (29.86%), soluble proteins (38.54%), and antioxidant enzyme activities. It was concluded that P. indica alleviates the negative effects of Cd on alfalfa plants to some extent. This is because P. indica can resist Cd stress and improve plant growth in cadmium-contaminated agricultural soil by alleviating membrane peroxidation damage, regulating osmotic regulatory substances, and enhancing enzyme activity to improve the antioxidant defense system. Thus, P. indica can be considered a biological fertilizer for improving plant growth and physiology in soils contaminated with cadmium.

This paper proposes a spatiotemporal fusion-based evapotranspiration inversion model (OL-SS) for grassland areas on the GEE platform. The model uses the OL processing strategy, with Landsat imagery being used as fine-resolution images and MCD43A4 imagery as coarse-resolution images, combined with GEE’s spatiotemporal fusion technology to generate 30 m resolution images. It then estimates the daily evapotranspiration of grasslands using the constant evaporation ratio method. The model was validated in the Xilin Gol League, Inner Mongolia, for grassland evapotranspiration inversion during the summer of 2015. The results show the following: 1. the OL-SS model can efficiently generate good spatiotemporal fusion results, but the fusion effect is poorer in some images due to cloud cover; 2. compared with the measured data from flux stations in grassland areas, the evapotranspiration inversion results show a good fit. The model demonstrates strong performance in grassland evapotranspiration monitoring and is suitable for the rapid estimation of daily evapotranspiration in certain grassland regions.

The degradation of sandy land in Inner Mongolia presents a substantial threat to regional ecological security and the sustainable development of agriculture and animal husbandry. Planting alfalfa serves as a crucial recovery strategy; however, the inadequate capacity to retain water and nutrients impedes this process. The current reliance on a singular microbial remediation method has demonstrated limited effectiveness in addressing the challenges posed by sandy soil. While traditional sand-fixing agents can improve soil nutrients, they lack biological activity. Furthermore, the synergistic mechanisms between these approaches and their ecological impacts within a single season remain poorly understood. This study involved a pot experiment utilizing wind-sand soil as the substrate to evaluate the soil physicochemical properties, enzyme activities, and microbial community structure associated with the stress resistance of alfalfa. The results indicated that the medium concentration of sand-fixing agent (1:75) exhibited optimal water retention performance, thereby creating a conducive growth microenvironment for Trichoderma longibrachiatum and mitigating fluctuations in surface temperature and humidity. The combined treatment significantly improved the alpha diversity of soil microorganisms, thereby improving the stability and stress resistance of the system. Through the synergistic approach of “sand fixation and water retention–nutrient activation–improved stress resistance”, the microenvironment of sandy land was effectively improved, promoting alfalfa growth. This method offers “environmentally friendly and synergistic” technical support for the efficient cultivation and ecological restoration of alfalfa in sandy regions, while also contributing to the high-quality development of grassland animal husbandry.