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Vegetation restoration is an effective means to increase the stability of aggregates and the ability of soil to resist erosion. At present, there are few studies on soil aggregate stability in contour trench and fish-scale pit grasslands (FPGs). Therefore, to determine the effects of different treatments on the stability of aggregates in the Loess Plateau, grazing grassland (GG), fencing grassland (FG), contour trench grassland (CG), and FPG were selected to compare distributions of soil aggregates, the soil aggregate stability, and soil erodibility K value. The results showed that <0.25-mm and >5-mm aggregates were the main components. The mass percentage of 5-0.25-mm aggregates in FG was significantly higher than that in GG, CG, or FPG. The proportion of large water-stable aggregates, mean weight diameter, and geometric mean diameter values were significantly higher in GG than in FG, CG, or FPG for topsoil, while FG had the highest WR 0.25 (70.21%) for subsoil. The opposite trends were found for fractal dimension and percentage of aggregate destruction values. The K values for CG and FPG were found to be significantly higher than those for GG and FG. A correlation analysis indicated that soil organic carbon can promote the stability of soil aggregates. A negative correlation was found between the comprehensive score and K values. In summary, FG had positive effects on soil aggregate stability and erodibility. This finding can guide the local government to adopt enclosure measures when implementing ecological restoration of degraded grasslands.

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Desert steppe soil security issues have been the focus of attention. Therefore, to understand the impact of industrial activities on the soil quality of desert grasslands, this experiment investigated the Gaoshawo Industrial Concentration Zone in Yanchi County. Based on the distance and direction from the industrial park, sample plots were established at intervals of 1–2 km. A total of 82 surface soil samples (0–20 cm) representing different pollution sources were collected. The samples were analysed for pH, total nitrogen, total phosphorus, available phosphorus, available potassium, organic matter, copper (Cu), cadmium (Cd), chromium (Cr), lead (Pb), and zinc (Zn). The desert steppe soil quality was analysed based on the integrated fertility index (IFI) and the Nemerow pollution index (PN), followed by the calculation of the comprehensive soil quality index (SQI), which considers the most suitable soil quality indicators through a geostatistical model. The results showed that the IFI was 0.393, indicating that the soil fertility was relatively poor. Excluding the available potassium, the nugget coefficients of the fertility indicators were less than 25% and showed strong spatial autocorrelation. The average values of Cu, Cd, Cr, Pb and Zn were 21.64 ± 3.26, 0.18 ± 0.02, 44.99 ± 21.23, 87.18 ± 25.84, and 86.63 ± 24.98 mg·kg−1, respectively; the nugget coefficients of Cr, Pb and Zn were 30.79–47.35%. Pb was the main element causing heavy metal pollution in the study area. Higher PN values were concentrated north of the highway in the study area, resulting in lower soil quality in the northern region and a trend of decreasing soil quality from south to north. The results of this research showed that the average SQI was 0.351 and the soil quality was extremely low. Thus, industrial activities and transportation activities in the Gaoshawo Industrial Zone significantly impact the desert steppe soil quality index.

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