Artificial shelterbelts in arid and semi-arid regions play a key role in controlling land degradation, regulating wind erosion, and maintaining ecological security. However, their long-term protective effectiveness increasingly depends on accurate degradation diagnosis and targeted management of aging and degraded stands. This study developed a comprehensive health assessment and degradation grading framework for poplar shelterbelts in the Kubuqi Desert, northern China, using an indicator system covering stand structure, community structure, soil conditions, health risks, and external disturbances. Indicator weights were determined using the entropy weight method, and degradation grades were classified by combining the technique for order preference by similarity to ideal solution (TOPSIS) model with the rank-sum ratio (RSR)–Probit method. The results showed that soil conditions and stand structure were the dominant dimensions distinguishing degradation status, with weights of 50.98% and 25.30%, respectively. Grade I, Grade II, Grade III, and Grade IV stands accounted for 21.88%, 25.00%, 34.38%, and 18.75% of the plots, respectively, indicating that lightly and moderately degraded stands were predominant. Degradation grades were also associated with changes in understory cover and surface soil nutrients, especially decreases in soil organic matter and alkali-hydrolyzable nitrogen. Based on these results, grade-specific management strategies were proposed, including conservation and maintenance, density regulation, assisted restoration, and near-natural transformation. This framework provides a practical basis for diagnosing degradation status and guiding the renewal and management of aging shelterbelts in arid sandy regions.

With the intensification of climate change, land use changes, and human activities, the ecosystems of the Ordos Plateau face severe challenges. This study evaluates the current ecological stability of the Ordos Plateau and makes future ecological zoning predictions based on the coupling analysis of landscape ecological risk (LER) and ecosystem service value (ESV). By analyzing the changes in LER and ESV from 2000 to 2023, the study reveals the response characteristics of the region’s ecosystems under climate change and land use changes. The results show that the rational utilization of grasslands and forests has effectively improved land use efficiency, reduced ecological risks, and enhanced ecosystem service value. Ecological restoration projects in the Mu Us Sandy Land and Kubuqi Desert have promoted the transformation of ecologically fragile areas (Zone IV) into optimized management areas (Zone II). However, the Kubuqi Desert remains a core area of ecological fragility. When planning for the future of the Ordos Plateau, it is important to pay attention to the scientific planning of arable land development to prevent further deterioration of the ecological situation. The future scenario prediction based on the intPLUS model indicates that reasonable ecological management policies will contribute to the sustainable development of the region. The research results provide a theoretical framework and practical reference for ecological restoration and management in the Ordos Plateau and similar arid and semi-arid regions.

Heavy metal contamination in seasonally frozen agricultural regions poses potential risks to food security in cold-climate croplands. However, the structural relationship between ecological risk and soil fertility under seasonal freeze-thaw climatic background remains insufficiently evaluated within an integrated soil health framework. In this study, five representative cropland soil types surrounding the Greater Khingan Range were investigated based on 370 soil samples collected from 0 to 40 cm profiles during the non-freezing season. The geo-accumulation index (Igeo), potential ecological risk index (RI), and a principal component-based soil fertility index (SFI) were integrated to construct a weight-adjustable Soil Health Index (SHI). Self-organizing feature mapping (SOFM) and hierarchical cluster analysis (HCA) were applied to identify coordinated variation patterns among heavy metals.Cadmium (Cd) exhibited pronounced enrichment relative to regional background values (40-146 times) and showed significant surface accumulation in the plow layer (0-10 cm), with concentrations 2.98-5.97 times higher than those at 30-40 cm depth. Although sampling was conducted outside the active freeze-thaw period and no direct freeze-thaw monitoring was performed, the observed vertical differentiation patterns are statistically consistent with redistribution processes reported in freeze-thaw-affected soils. Alternative explanations such as long-term surface inputs, tillage mixing, and soil texture effects cannot be excluded.SHI evaluation revealed structural mismatches between fertility and ecological risk, particularly in soils characterized by relatively high fertility but elevated Cd risk. SOFM and HCA consistently grouped Cd and Ni as co-varying elements, whereas Cr and Cu displayed relatively stable patterns indicative of stronger lithogenic control. The findings provide a process-constrained statistical assessment framework for evaluating pollution-fertility interactions in seasonally frozen croplands. The results should be interpreted as pattern-based inference under freeze-thaw background conditions rather than direct mechanistic verification of freeze-thaw effects.

Many rivers are tightly coupled and intersected with aeolian sand dunes, whose geomorphological evolution involves not only fluvial processes but also aeolian processes that pose a new challenge to fluvial geomorphological studies. However, due to few field studies, our overall understanding of the desert channel geomorphic process is limited. In this paper, we present an outstanding example of desert river channel evolution regulated by aeolian–fluvial interactions in the Ulan Buh Desert of the Yellow River, based on a long time series data set (1966–2019) of channel cross-sections. The results indicate that the lateral addition of aeolian sand, the water–sediment relationship and human interference have a significant role at different periods of channel evolution. Before 1986, higher discharge, lower sediment content and greater intensity of aeolian activity caused aeolian–fluvial interactions and a relative scouring and silting balance in the channel, with little human activity. From 1986 to 2000, an increase in large reservoir operation, vegetation coverage and floodplain farming, coupled with water–sediment relationship variation, caused rapid deposition and shrinkage of the river channel. From 2000 to 2014, the channel kept a slight scouring state. With Haibowan reservoir operation beginning in 2014, the talweg experienced rapid scouring and undercut rebound. However, an expanding and stable floodplain accelerated sedimentation on the floodplain and weakened river lateral erosion, indicating that the channel has shown a shrinkage trend. Meanwhile, wavelet analysis results indicate that human interferences and aeolian activities have no significant role in the periodical characteristics of the channel’s longitudinal erosion and deposition. Therefore, on the whole, increasing human interferences and decreasing wind dynamics have driven this desert wandering channel to be stable, and to gradually form a new balance between erosion and sedimentation.

Monoculture and legume–grass mixed cropping are the two most common planting methods, with mixed cropping generally demonstrating higher hay yield and superior nutritional quality compared to monoculture. However, research on legume–grass mixed cropping for establishing cultivated pastures in typical sand-fixing vegetation areas of the Mu Us Sandy Land remains scarce. These knowledge gaps have hindered the synergistic integration of forage production and ecological restoration in the region. This study conducted mixed cropping trials in the sand-fixing vegetation zone of the Mu Us Sandy Land using Dahurian wildrye (Elymus dahuricus), Mongolian wheatgrass (Agropyron mongolicum), and Standing milkvetch (Astragalus adsurgens) to investigate the effects of species combinations and planting ratios on forage productivity and nutritional quality, aiming to determine the optimal planting strategy. Results showed that in the first establishment year, the yield of all mixed cropping systems significantly exceeded that of monocultured Dahurian wildrye and Mongolian wheatgrass. All mixed cropping combinations exhibited land equivalent ratios (LER) and relative yield totals (RYT) below 1, indicating varying degrees of interspecific competition during the first year, with grass species generally demonstrating stronger competitive abilities than legumes. Mixed-cropped forages showed higher crude protein, crude fat, and crude ash content compared to monocultures, alongside lower neutral detergent fiber (NDF) and acid detergent fiber (ADF) levels, suggesting improved relative feed value (RFV). Among the combinations, E₅A₅ and E₆A₄ (5:5 and 6:4 ratio of Dahurian wildrye to Standing milkvetch) achieved higher RFV, with RFV gradually declining as the legume proportion decreased. In conclusion, both monoculture and legume–grass mixed cropping are viable in the Mu Us Sandy Land’s sand-fixing vegetation areas and the E₅A₅ combination (5:5 ratio of Dahurian wildrye to Standing milkvetch) as having the highest overall score, demonstrating that this mixed cropping ratio optimally balances yield and nutritional quality, making it the recommended planting protocol for the region. This mixed cropping system offers a theoretical foundation for efficiently establishing artificial pastures in the Mu Us Sandy Land, supporting regional pastoral industry development and desertification mitigation.