The study area is located at the northern edge of the Hobq Desert, within the Duguitala Industrial Park in Hangjin Banner, Ordos City (107°10′ E–111°45′ E, 37°20′ N–39°50′ N) ( Figure 1A ). The region has a temperate continental monsoon climate, with an average annual temperature of 6°–7°C, low precipitation (average annual rainfall of 227 mm), and high evaporation (2,400 mm annually). The desert’s harsh conditions reflect the challenges posed by desertification and land degradation. The soil is primarily sandy, with an average vegetation coverage of less than 5%. The total annual solar radiation in this area is 597.9 KJ/cm² further underscoring its suitability for PV installations aimed at exploring sustainable energy solutions while addressing desertification (Tang et al., 2021).

The experimental plots are located within the third phase of the Yili Ecological PV Zone (100 MW), a fixed PV power station that began operating in 2016. The PV panels are arranged in a fixed east–west direction with a southward tilt of 36°, leaving a 900-cm north–south spacing and 110-cm east–west row spacing between arrays. Each row consists of 12 panels, and each panel contains 34 cells. The dimensions of each panel are 400 cm by 800 cm. The front edge of the panels is 50 cm above the ground, while the rear edge is 300 cm above the ground. The entire PV station is uniformly covered with a red clay substrate.

The experiment was conducted in the third phase of the Yili Ecological PV zone, within a fixed PV power station. This area serves as a specialized experimental zone for vegetation restoration. To optimize the use of space around the solar panels and enhance wind erosion control, A. adsurgens (a sand-binding plant) was planted in 2020 before, behind, and under the PV panels using hole-sowing methods. Given the underlying surface effects and to improve the survival rate of the plants, the area around the panels was leveled and treated with a uniform layer of red loam to ensure consistency in the substrate. The seeds were sown in holes during the post-wind season and before the onset of the rainy season, with a spacing of 0.6 m × 1 m between the plants and covered with 1–2 cm of soil.

To investigate the plant’s growth characteristics and physiological responses, the 2022 growing season (June to August) was selected for the study. Three parallel rows of PV panels from the central region of the PV array were designated as the study area, with CK samples taken from the area outside the PV station without any panels. Three 50-m-long sample lines (sample lines 1, 2, and 3) were laid out in the east–west direction before, behind, and under the panels ( Figure 1B ). Specifically, plants before panels are located in open areas and exposed to direct sunlight (Monthly average 1 hour 38 minutes), while plants under panels are partially shaded and receive less sunlight by the location of the panels (Monthly average 10 hour 33 minutes). Plants behind panels were in shade for most of the day and received limited direct sunlight (Monthly average 9 hour 42 minutes). Sampling quadrats (50 cm × 50 cm) were established along each transect at 10-m intervals. Within each quadrat, 12 morphologically similar and evenly growing A. adsurgens plants were selected, and growth parameters such as plant height, leaf length, leaf width, and leaf thickness were measured monthly. To capture physiological responses, leaf samples from three plants per quadrat were collected and immediately placed in resealable bags and stored in a refrigerated cooler for transport to the laboratory. In the lab, leaves were separated from the midribs, and the appropriate sample mass for each physiological indicator was measured according to the experimental requirements. Field measurements were taken from the 24th to the 28th of each month, and laboratory analyses were completed within 7 days of sample collection. The specific method is shown in Figure 2 .

The artificial squatting timing method was used to observe and record the shading conditions of the before, behind, and under panels from 07:00 to 19:00 hours as the observation period under clear and cloudless weather conditions. Finally, the average value was found based on the shading time of each location in 3 months. According to the observation of the shade time of each position of the PV panels in the experimental sample site, the shade time of the before panels, behind panels, and under panels in June was 2 h 35 min, 9 h 10 min, and 10 h 20 min, respectively; in July, it was 2 h, 9 h 30 min, and 10 h 40 min, respectively; and in August, it was 20 min, 10 h 25 min, and 10 h 40 min, respectively. Therefore, the shading time at different locations of the PV panels showed that under panels > behind panels > before panels > CK (0 min).

A tape measure was used to determine the plant height of A. adsurgens, from the base of the stem to the distance between leaves in their upright position. Leaf length and width were measured using an electronic caliper with a precision of 0.01 mm. Leaf thickness was determined by measuring the combined thickness of the front, middle, and rear sections of the leaf, and the average value was calculated, excluding the central vein. The leaf was placed on a black cardboard with a known fixed area (used as a reference) and photographed from a fixed height. Photoshop software was used to process the image and calculate the location of a single leaf. The scanned leaves were then dried in an oven at 85°C until constant weight was achieved, and the dry weight of the leaf was determined using a balance with a precision of 0.001 g. The leaf area was calculated using the following formula:

where S_single__leaf represents the area of a single leaf (cm²), N_leaf is the number of pixels that correspond to the leaf area in the image, N_reference is the number of pixels corresponding to the reference object in the same image. S_reference is the area of the reference object (cm²). SLA represents the specific leaf area (cm²/g), and W_{single_leaf} is the dry weight of a single leaf (g).

Before analyses, the Shapiro–Wilk normality test and Levene’s test were used to test the normality and homogeneity of variance of the variables, respectively. If the assumptions were met, one-way analysis of variance (ANOVA), LSD multiple comparison tests, and correlation analyses were used for multiple comparisons. All statistics were performed using SPSS software (v.20.0, SPSS Inc., Chicago, USA). Significant differences were indicated with letter markers. A membership function method was used to comprehensively evaluate the A. adsurgens plants at different locations. All graphical representations were generated using Origin 2024 software (OriginLab, USA).

As shown in Table 1 , during the growing season (June–August), the plant height, leaf length, and leaf width of A. adsurgens growing before, behind, and under the fixed PV panels were greater than those of the CK. The growth was most pronounced in the under panels, with increases of 49.67%, 58.43%, and 21.84%, respectively, by the end of the observation period. In contrast, leaf thickness followed the CK > before panels > behind panels > under panels. Moreover, the SLA was highest in under panels, reaching a peak of 221.86 cm²·g⁻¹ in August, indicating the most muscular photosynthetic capacity in this area. In summary, the A. adsurgens plants surrounding the PV panels adapted to the shaded environment by adjusting their height and leaf morphology to enhance light capture compensating for reduced photosynthesis. On the other hand, the CK adapted by developing shorter, thicker, and smaller leaves to improve water retention and reduce transpiration. These adaptive changes are closely related to microclimate variations and promote the growth and development of A. adsurgens around the PV panels.

During the growing season, the N and CP content of A. adsurgens located before, behind, and under PV panels were significantly higher than those in the CK, with increases of 51.40%, 87.30%, and 85.81%, respectively ( Figure 3 ). In June, the P content was highest in plants growing under panels. However, in July and August, the under panels had the highest P content, reaching 0.16% and 0.19%, respectively. Throughout the growing season, the N:P of A. adsurgens exceeded 14 indicating that its growth was not limited by N, and the presence of PV panels did not negatively impact nitrogen accumulation. The N:P in the before, behind, and under panels’ plants were all greater than 16, suggesting that A. adsurgens growth in these locations was limited by P. In July, the N:P in the CK ranged between 14 and 16, which showed that its growth was co-limited by both N and P. Thus, planting A. adsurgens around PV panels can prevent N limitation and improve its N absorption capacity.

Principal component analysis (PCA) showed that within the 95% confidence interval, the influence of different locations around the PV panels on the growth and physiological indices of A. adsurgens exhibited significant differences. PC1 and PC2 explained 60.8% of the variation in plant growth and physiology highlighting the critical impact of PV panel interference on growth and physiological characteristics (Figure 7A). Specifically, leaf length, SLA, P content, and POD activity were positively correlated (p < 0.05) (Figure 7). Conversely, leaf thickness was negatively correlated with SLA and P content (p < 0.05) indicating that A. adsurgens adopts adaptive strategies to adjust to different light conditions. In addition, SS were negatively correlated with Chl content (p < 0.05), while Chl a/b was negatively correlated MDA content (p < 0.05) (Figure 7B). Finally, a comprehensive evaluation of the growth and physiological status of A. adsurgens was conducted using a membership function analysis of 19 physiological indicators. The average membership function value for each indicator at a given location was used as a quantitative measure of plant growth, with higher values indicating better growth conditions. As shown in Table 3 , the ranked growth status of A. adsurgens in different locations around the PV panels is as follows: under panels > before panels > behind panels > CK.

The root, stem, and leaves are critical organs for photosynthesis and respiration, and environmental conditions are primary factors influencing plant growth (Desalme et al., 2011; Yin et al., 2021; Lv et al., 2023). This study demonstrates that the height, leaf length, and leaf width of A. adsurgens near the PV panels were 1.10 to 1.99, 1.01 to 2.40, and 1.03 to 1.47 times greater, respectively, compared to those of the control group ( Table 1 ). This suggests that the environmental modifications induced by the PV arrays facilitated plant growth. Notably, A. adsurgens exhibited the most pronounced growth in under panels. By reducing sunlight exposure and solar radiation, the PV panels altered the red to far-red light ratio affecting the plant’s photoreceptor response and promoting increased plant height and leaf size for more efficient light capture. Furthermore, growth disparities between the before and behind the panels suggest that, although the area behind panels experiences longer shading periods, the light and microclimate conditions before panels are more conducive to plant growth. These findings are consistent with those of Yue et al. (2021a), who reported that PV panels provide a cooling and humidifying effect in summer, particularly in arid regions, thereby enhancing the vegetation growth environment. The growth characteristics of A. adsurgens in this study highlight its strong adaptability to heterogeneous light conditions.

N and P are indispensable nutrients for plant growth, while CP is an important indicator of plant quality (Kumar et al., 2021). This study revealed that the N and CP contents of A. adsurgens around the PV panels were higher than those in CK, and the P content under panels was significantly increased ( Figure 3 ). This was possible because increased blue-violet light prompted the conversion of carbon metabolism to N metabolism, while shade reduced photosynthetic products, thereby promoting N accumulation. The N:P is often used as a measure of plant growth limitation. Koerselman and Meuleman (1996) suggested that plant growth and development are mainly limited by N when the N:P is less than 14, P when the ratio is greater than 16, and both when the ratio is between 14 and 16. The N:P around the PV panels were all greater than 16, which shows that planting A. adsurgens in PV plants can effectively avoid the N limitation on their growth. Additionally, the shading effect of the PV panels increased Chl b content in A. adsurgens enhancing its ability to utilize light energy in low-light conditions. The increase in Chl content was also linked to soil moisture (Liu et al., 2018) aligning with this study’s finding that shading duration under the PV panels was the longest, and Chl content was higher than that in CK ( Table 2 ). During the summer months (June to August), temperatures in the study area increased peaking in July. Changes in soil moisture often lag behind temperature fluctuations, and plants are more sensitive to soil moisture than temperature (Sun et al., 2018). As a result, A. adsurgens increased its osmotic adjustment capability in late August to enhance water retention in response to declining soil moisture. Moreover, the SS and SP contents of A. adsurgens near the PV panels were higher than those in CK indicating that the plant’s accumulated intracellular solutes improved water retention and adapted to reduced soil moisture ( Figure 4 ). Elevated MDA levels indicated that plants under the panels may experience environmental stress ( Figure 5 ). Still, increased SOD and POD activities reflected the strong antioxidant capacity of A. adsurgens further confirming its resilience to the conditions under the PV panels ( Figure 6 ).

This study underscores the ecological potential of A. adsurgens in different locations within a PV power station and concluded that, due to the shading effect from PV panels, A. adsurgens shows the highest tolerance under panels, followed by the areas before and behind panels, with the CK showing the lowest tolerance ( Table 3 ). Based on this, the following optimization strategies were recommended to maximize the application of plants in ecological restoration within PV stations: 1. Optimization of the ecological layout before panels: Given the favorable light conditions in this area, it is recommended to plant low-growing, drought-resistant, and wind erosion-resistant species to minimize shading impacts on PV panel efficiency while enhancing the station’s wind erosion control. 2. Enhance fertilization management: During the growth period of A. adsurgens, increase the application of P fertilizer and adjust the N:P ratio to alleviate P limitation and improve plant growth efficiency. Fertilizer application should be adjusted based on soil conditions, with careful attention to avoid overfertilization, which could lead to nutrient imbalances or soil salinization. Water management should also be coordinated to prevent fertilizer runoff. 3. Regular monitoring and dynamic adjustments: It is recommended to deploy environmental monitoring sensors to track soil moisture, temperature, and other relevant data in real time and periodically assess plant growth conditions. Based on the monitoring results, adjustments should be made to irrigation volumes, fertilization strategies, and planting density to ensure the healthy growth of vegetation. This optimization measures fully exploit the significant ecological potential of A. adsurgens in PV power stations effectively promoting the harmonious coexistence of PV energy generation and ecological environmental protection.