The goal of this study was to investigate the soil particle-size distribution (PSD) and pore structure characteristics in the Kubuqi Desert in order to provide basic data for gaining insights into the soil-modifying properties of the local vegetation. Based on laser diffraction analysis, we measured the soil PSD and calculated the single and multi-fractal dimensions of the soils under typical artificial forest and natural grassland vegetation. The diameters, volumes and surface areas of the soil pores were determined via nitrogen adsorption experiments. The relationships between the fractal characteristics and pore structure parameters of the soil were investigated via redundancy analysis and stepwise regression. The clay content was less than 2.0%, and the sand content was greater than 75.0%. There was variability in the PSD and fractal dimension, which was mainly observed for the 0–20 cm, 20–80 cm, and 80–100 cm soil layers. In the 0–80 cm, the fine particle content, single fractal dimension (D), entropy dimension (D₁), ratio of D₁ to the capacity dimension (D₁/D₀), and correlation dimension (D₂) were smaller for the forest soils than for the grassland soils. The fine particle (clay and silt) content of the 80–100 cm soil layer was approximately 37.8% higher for the Salix psammophila-8a than for the Salix psammophila-3a, and it was approximately 161.4% higher for the Populus popular-35a than for the Pinus sylvestris var. mongolica-8a. The silt content, D₁, D₁/D₀, and D₂ were significantly positively correlated with the specific surface area (SSA), total pore volume (TPV), and average pore diameter (APD) of the nanopores (p &lt; 0.05, 0.01, or 0.001), and they were significantly negatively correlated with the percentage of the micropore volume (PMV) (p < 0.05 or 0.01). In the Kubuqi Desert, the fine particle content and fractal dimensions of the soil layer below the root zone of shrub and arbor vegetation increased with increasing stand age, but the trend was reversed in the shallower soil layers. The variability of the soil PSD characteristics was strongly correlated with the variability of the nanopore parameters on the microscopic scale, suggesting that the total pore volume, average pore diameter, and percentage of the micropore volume may be potential indicators of the soil structure and quality.

Water shortages are the main factor restricting the survival and construction of shelterbelts in sandy areas. Comprehensive analysis of the water balance characteristics of forest stands is crucial for scientifically understanding and regulating the water supply of shelterbelts in sandy areas and formulating appropriate vegetation cultivation and restoration strategies. We simultaneously monitored outer-forest precipitation, canopy interception, stemflow, throughfall, forest transpiration, understory evapotranspiration, and soil moisture content changes in the Salix forest in the Kubuqi Desert during the main growing season (June–October) of 2022. The results showed that the total evapotranspiration of the forest was 185.62 mm, and the components and their proportions of precipitation during the same period were as follows: forest floor evapotranspiration, 94.43 mm (35.88%); stand transpiration, 68.34 mm (25.97%); and canopy interception, 22.85 mm (8.68%). Based on the water balance of the 0–60 cm soil layer and by integrating the changes in soil water storage and the influence of external water transport, the net runoff of the forestland was calculated to be approximately 77.58 mm; that is, the water balance requirements for growth were met. In the future, appropriate irrigation and supplementation can be carried out in June and July to ensure healthier growth in the shelterbelt, and plant photosynthesis and internal physiology can be further studied for cultivation in other desert areas.

The Chinese pearleaf crabapple tree, belonging to the Rosaceae family and with the scientific name Malus asiatica, bears fruits that serve as both food and medicine. The Horqin Right Wing Front Banner is a critical node for ecological security in the northern border regions of China, exerting significant influence on ecological health in China. Additionally, the resources in this region are limited, and residents have historically relied solely on maize cultivation for sustenance. Therefore, local measures combining ecological conservation and economic development have been implemented in vigorously promoting the Chinese pearleaf crabapple industry. Hence, it is necessary to study the ecological suitability of the local Chinese pearleaf crabapple. In this study, 15 evaluation indicators are employed for this purpose, with the analytic hierarchy process (AHP) used to calculate single-factor weights. Additionally, GIS is utilized to establish membership functions for achieving dimensionless evaluation indicators, as well as a weighted index and model used to compute comprehensive suitability scores. Using the natural breakpoint method, the overall scores were categorized into five groups: most suitable, more suitable, barely suitable, unsuitable, and not applicable. The validation of zoning results includes verification of existing planting locations and conducting principal component analysis of the characteristics and yield of Chinese pearleaf crabapple to ensure the accuracy of the zoning. It is found that the validation results are generally consistent with the zoning results. The results indicate that the most suitable, more suitable, suitable, barely suitable, and unsuitable represent 16.49%, 32.07%, 30.36%, 14.52%, and 6.55% of the total zoning area, respectively. These findings can be applied to land use planning and in expanding the planting area of Chinese pearleaf crabapple.

Given the significant regulatory effect of stumping on carbon exchange processes in the vegetation–soil system, this study conducted a one-year continuous observation of soil respiration in Salix psammophila stands starting six months after stumping, aiming to reveal the changes in soil respiration characteristics and their main driving factors before and after stumping. In 2023, a stumping experiment was established in Dalate Banner, Ordos, and soil respiration in stumped Salix psammophila plantations was continuously monitored from 2023 to 2024. The relationships between soil respiration, soil temperature, and soil moisture were analyzed using fitting models, and the effects of stumping on soil physicochemical properties were further assessed. Results showed that soil respiration exhibited a unimodal diurnal pattern, reaching the annual minimum in winter (December 2023) and the maximum in midsummer (August 2024). Stumping significantly reduced soil respiration rates across diurnal, seasonal, and annual scales. This reduction was attributed both to direct effects, through decreased vegetation carbon input and altered root distribution, and to indirect effects, via changes in soil temperature and moisture. Model fitting indicated that the dual-factor model incorporating soil temperature and moisture explained variations in soil respiration more effectively than single-factor models, with the bivariate nonlinear model providing the best fit. In addition, stumping improved the vertical distribution of soil nutrients by enhancing the accumulation of organic matter and organic carbon in the middle soil layer and increasing total nitrogen content in the surface soil. Soil pH showed only slight variations across treatments and depths, remaining consistently within the strongly alkaline range (9.37–9.56).

Salix psammophila, classified under the Salicaceae family, is a deciduous, densely branched, and erect shrub. As a leading pioneer tree species in windbreak and sand stabilization, it has played a crucial role in combating desertification in northwestern China. However, different genetic sources of Salix psammophila exhibit significant variations in their effectiveness for windbreak and sand stabilization. Therefore, it is essential to establish a rapid and reliable method for identifying different Salix psammophila varieties. Visible and near-infrared (Vis-NIR) spectroscopy is currently a reliable non-destructive solution for origin traceability. This study introduced a novel feature selection strategy, called qualitative percentile weighted sampling (QPWS), based on the principle of the long tail effect for Vis-NIR spectroscopy. The core idea of QPWS combines weighted sampling and percentage wavelength selection to identify key wavelengths. By employing a multi-threaded parallel execution of multiple QPWS instances, we aimed to search for the optimal feature bands to address the instability issues that can arise during the feature selection process. To address the problem of reduced prediction performance in one-dimensional convolutional neural network (1D-CNN) models after feature selection, we have introduced convolutional autoencoders (CAEs) to reduce the dimensions of wavelengths that are discarded during feature selection. Subsequently, these reduced dimensions are fused with the selected wavelengths, thereby enhancing the model’s performance. With our completed model, we selected outstanding models for model fusion and established a decision system for Salix psammophila. It is worth noting that all 1D-CNN models in this study were developed using Bayesian optimization methods. In comparison with principal component analysis (PCA) and full spectrum methods, QPWS exhibits superior predictive performance in the field of machine learning. In the realm of deep learning, the fusion of data combining QPWS with CAE demonstrated even greater potential with an improvement of average accuracy of approximately 2.13% when compared to QPWS alone and a 228% increase in operational speed compared to a model with full spectra. These results indicated that the combination of CAE with QPWS can be an effective tool for identifying the origin of Salix psammophila.

To conduct ecological restoration in the Kubuqi sandy land and to select suitable superior Salix psammophila provenances, four provenances were selected from Dalate Banner, Ordos (DLT), Wushen Banner, Ordos (WSQ), Yulin, Shaanxi (YL), and Yanchi, Ningxia (YC). All cuttings were interplanted and established at an experimental site, and stumping was conducted five years after establishment. Six months after stumping, 11 parameters, including growth characteristics, gas exchange parameters, and photosynthetic pigments, were systematically measured. There were significant differences in plant height and branch number among Salix psammophila from different provenances, while there was no significance in the number of branches among different provenances. The daily variation in net photosynthetic rate (Pn) was significantly different among various Salix psammophila from different provenances, with highest in that from WSQ. The daily variations in stomatal conductance (Gs) and transpiration rate (Tr) from various provenances are relatively consistent, showing a unimodal trend. In terms of pigment content, the WSQ provenance exhibited the highest chlorophyll a content, while the YC provenance showed the highest carotenoid content. The variation coefficients of each parameters ranged 2.607–40.619%, with the highest for branch number, while the lowest for intercellular CO₂ concentration. Cluster analysis divided the Salix psammophila from four provenances into two groups, with DLT and YL being one group, and WSQ and YC being the other one. The results of entropy weight TOPSIS showed that the comprehensive ranking of various provenances was: WSQ > YC > YL > DLT, indicating the physiological properties of WSQ being superior to others, indicating its relatively high ecological adaptability in the semi-arid environment of the Kubuqi sandy land, and it can be used as a preferred provenance for ecological restoration and promotion applications.