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.

In the extremely arid Gobi environment, it remains unclear whether afforestation with saxaul (Haloxylon ammodendron) is an effective ecological restoration strategy or whether it may trigger ecological risks under severe water limitation. This study examined saxaul shelterbelts of different ages across precipitation gradients (0–50, 50–100, and 100–150 mm·yr⁻¹) in the Alxa Gobi based on 48 plots. It systematically assessed the effects of precipitation on stand growth, soil particle-size distribution, and nutrient dynamics inside and outside plantations, and used partial least squares path modeling (PLS-PM) to analyze the coupling mechanisms among precipitation, soil, and plant growth. The results showed that precipitation was the key factor controlling the survival and growth of saxaul, while planting density further regulated survival rates within different precipitation zones. Plant height, crown width, and basal diameter generally showed better performance in higher-precipitation zones, although differences among plantation ages may have been influenced by variation in initial planting density. Among the three precipitation zones, plants in the 100–150 mm zone exhibited the best growth performance. In low-precipitation areas (≤50 mm), the growth of saxaul was strongly limited, and afforestation disturbance was associated with disruption of the surface gravel layer, soil coarsening, and inadequate nutrient accumulation. In contrast, in medium- and high-precipitation areas (50–150 mm), saxaul plantations established at appropriate densities are more conducive to the accumulation of fine soil particles and nutrient enrichment. Correlation heatmaps and PLS-PM results further showed that precipitation gradient, soil texture, soil fertility, and plant growth were closely coupled. Moreover, the associations between soil and vegetation variables were stronger inside the shelterbelts than outside the shelterbelts, indicating that more pronounced local soil–vegetation feedbacks may have been formed after the establishment of artificial Haloxylon ammodendron stands. Overall, the suitability of saxaul plantations in the Alxa Gobi showed clear precipitation-dependent differentiation, with approximately 50 mm representing a practical lower limit for saxaul plantation establishment. Large-scale saxaul plantations is not recommended in areas with precipitation ≤ 50 mm, where low-disturbance restoration focused on gravel-layer protection should be prioritized; in contrast, areas receiving 50–150 mm precipitation are more suitable for plantation establishment under appropriate density control. These findings provide a scientific basis for sustainable afforestation, regional allocation, and low-disturbance management in extremely arid Gobi regions under the principle of matching vegetation restoration to water availability and site conditions.

Rhus typhina L. is widely recognized as a landscape ornamental plant and its extracts have demonstrated biological activity against multiple weed types. This makes it a promising candidate in sustainable agriculture as a bioherbicide by offering a solution to mitigate the growing problem of herbicide resistance. Therefore, this study was designed in agar culture to analyze the effect of powders of the branch, fallen leaf, and pericarp from Rhus typhina L. against seed germination of Portulaca oleracea L. and evaluate its inhibitory mechanisms based on anatomical structure and the activities of antioxidative enzymes, α-amylase, and β-amylase. The main allelopathic compounds were also identified based on high-performance liquid chromatography–mass spectrometry (LC-MS), and their bioherbicidal effects were evaluated. Brassica napus L. was used as the object for biosafety evaluation. The results showed that the seed germination of Portulaca oleracea L. under treatment with powder extract from Rhus typhina was inhibited by exhhibting swelling and deformation in endosperm cells and chaotically scattered starch granules in seed embryos with a shorter radicle length than the control. During the period of treatment, antioxidative enzymes were quickly activated to scavenge the suddenly surging reactive oxygen species (ROS) as a measure of boosted malonaldehyde (MDA) content. Antioxidative enzyme (POD, SOD, and CAT) activities were also activated to mitigate the oxidative damage. In contrast, both α-amylase and β-amylase activities were significantly suppressed. A total of 16 allelochemicals were identified in the branch, fallen leaf, and pericarp of Rhus typhina L. Among these, gallic acid, methyl gallate, and tyrosol were identified as exhibiting the most significant inhibitory effect during the whole germination process of Portulaca oleracea L., resulting in browned seedlings and stunted radicle length compared with the control, while far weaker inhibitory effects were found against Brassica napus L. In summary, extracts from Rhus typhina L. targeted α-amylase and β-amylase activities rather than antioxidative enzyme activities to inhibit the germination of Portulaca oleracea L. Gallic acid, methyl gallate, and tyrosol were the key compounds that inhibited its germination.

This study examined the concentration-dependent effects of an aqueous extract of Artemisia annua on seed germination and seedling morphological and physiological traits in the invasive plant Solanum rostratum. The extract was also subjected to preliminary chemical profiling using LC–MS/MS. Seed germination was examined in Petri dishes at 50, 100, 150, 200, and 250 g L⁻¹, whereas seedling responses were examined in independent plug cells at 100, 150, 200, 250, and 300 g L⁻¹. Distilled water served as the control in both experiments. Widely targeted LC–MS/MS profiling of the 300 g L⁻¹ extract yielded 9987 putative metabolite annotation entries across ten superclasses, with phenylpropanoids, alkaloids, and terpenoids, constituting the three largest superclasses by number of annotation entries. Seed germination was suppressed at all tested concentrations and completely inhibited at ≥150 g L⁻¹. Seedling responses were concentration-dependent: several morphological indices increased at 100–150 g L⁻¹ while gas-exchange performance declined, whereas morphological inhibition became increasingly evident at ≥200 g L⁻¹. Net photosynthetic rate, stomatal conductance, and transpiration rate declined with increasing extract concentration and were significantly lower under all extract treatments than in the control. Chlorophyll a and chlorophyll b contents initially increased and then decreased, with both peaking at 150 g L⁻¹. Carotenoid content increased across the concentration gradient, whereas intercellular CO₂ concentration exceeded the control only at ≥200 g L⁻¹. Electrolyte leakage and the contents of malondialdehyde, H₂O₂, and proline generally increased with extract concentration, with the highest values observed at 300 g L⁻¹. Catalase activity was significantly lower than that of the control at ≥200 g L⁻¹. At high concentrations, morphological inhibition coincided with reduced photosynthetic performance, changes in antioxidant enzyme activities, and increased indicators of oxidative stress and membrane damage. These findings provide laboratory evidence of the phytotoxic potential of A. annua aqueous extract but do not establish its efficacy or safety under field conditions.

The health of desert plant life is closely linked to the stability of the local ecological equilibrium, where both human actions and shifts in climate serve as primary influences on environmental security. This research examined the temporal and spatial variations in vegetation NDVI and climatic elements within the Kubuqi Desert between 2000 and 2023. It utilized partial correlation analysis, multiple linear regression, and the geodetector method to uncover the underlying drivers of NDVI dynamics. Additionally, the study applied an ARIMA model to forecast the NDVI trajectory for the upcoming five-year period. The findings indicated that: (1) Plant life in the Kubuqi Desert has experienced substantial enhancement, with more than 80.61% of the region demonstrating a highly notable upward trajectory in NDVI; nonetheless, the general vegetation is projected to display slight anti-persistence going forward. (2) Annual precipitation, annual average high temperature, and annual average low temperature all showed an increasing trend. (3) Land transfer mainly occurred among barren land, cultivated land, and grassland, with the conversion from barren land to grassland accounting for 15.49%. (4) Precipitation and high temperature are key factors affecting NDVI distribution, with a 2–3month lag effect on NDVI. (5) Vegetation NDVI will show an increasing trend over the next five years. This study will provide certain data support for vegetation restoration strategies in the Kubuqi Desert.

The Northern Sand Prevention Belt is an important ecological security barrier in China. It is also one of the regions most severely affected by wind-eroded desertification. In this study, to investigate differences in soil properties among different vegetation types in sandy areas, a typical vegetation restoration area in the Horqin Sandy Land was selected. Widely distributed natural forests of Ulmus pumila, Populus plantations and Pinus sylvestris var. mongolica plantations were the study objects, with bare sandy land as the control. Understory herbaceous plant diversity and soil hydrological and physical properties were analysed, and Pearson correlation analysis, principal component analysis and the fuzzy membership function method were employed to comprehensively evaluate the soil water conservation function with respect to different vegetation types. The results showed that soil hydrological and physical properties differed significantly among the vegetation types. The U. pumila forest exhibited relatively low soil bulk density (1.53 g·cm⁻³) and high total porosity (32.42%) in the deep-soil layer (80–100 cm), indicating a strong capacity for deep-soil water storage. The Populus plantation showed the greatest soil improvement in the surface layer, with the highest capillary water-holding capacity and field water-holding capacity, reaching 17.82% and 16.05%, respectively. The P. sylvestris var. mongolica plantation had relatively high deep-soil bulk density (1.60 g·cm⁻³) and a pronounced decline in water-holding capacity. The unvegetated sandy land had the lowest capillary water-holding capacity (15.09%) and very poor water-retention capacity. Understory herbaceous plant diversity was highest in the P. sylvestris var. mongolica plantation and lowest in the U. pumila forest, and herbaceous plant diversity was significantly correlated with soil capillary porosity and capillary water-holding capacity. This comprehensive evaluation indicated that the poplar and P. sylvestris var. mongolica plantations had greater soil water conservation capacity than the natural U. pumila forest and unvegetated sandy land, with the tree–herbaceous vegetation structure exhibiting stronger synergistic characteristics and relatively favourable soil moisture conditions. These findings suggest that greater attention should be given to tree–herbaceous synergistic configurations in vegetation restoration in the Northern Sand Prevention Belt, while tree species selection should be optimised according to local conditions to enhance regional soil water conservation capacity.