Microplastics pollution in agricultural soil is increasingly recognized, but the specific situation varies with geography, climate conditions, and farming practices. The karst landscape, a typical geomorphology in China, demands a deeper understanding of microplastics pollution in such areas. This research zeroes in on Guizhou, a province known for its karst formations, by collecting soil samples from the mulched cultivation layer in ten counties and cities. The study employed metallographic microscopy, scanning electron microscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FT-IR) to analyze the presence and distribution of microplastics. Results show that polyethylene is the predominant component of microplastics in the mulched agricultural soils of Guizhou, primarily existing as irregular fragments in black, transparent, and translucent forms, with diameters of 40 ~ 120 μm and rough surfaces marked by significant erosion. The concentration of microplastics varies from 143.28 to 3,283.46 items/kg, averaging 1,150.60 ± 647.86 items/kg. The majority of particles accounting for 64.79% are sized between 10 ~ 100 μm. A highly significant positive correlation (p < 0.001) is found between mulching duration and microplastics concentration, indicating that prolonged mulching increases microplastics accumulation in farmlands. Additionally, crop type, irrigation method, and soil type also influence microplastics concentration. This study highlights the escalating issue of microplastics pollution in China’s karst regions, underscoring the need for attention.

The environmental effects caused by the proliferation of microplastics have received extensive attention. However, at this stage, there is a lack of research on the toxicology of microplastics and their impacts on plants. This study explored the effects of microplastics on the growth and physiological characteristics of tobacco. Using tobacco (Nicotiana tabacum L.) variety Yunyan87 and low-density polyethylene (LDPE, 13 μm particle size), different concentrations, which were 0 mg/L (CK), 10 mg/L (T1), 100 mg/L (T2), and 1000 mg/L (T3), were subjected to hydroponic experiments to study the effects of microplastics on the growth and physiological characteristics of tobacco. The results showed that microplastics had a certain inhibitory effect on the growth of tobacco. Among them, high concentrations of microplastics significantly inhibited the root architecture and growth characteristics. According to the performance observed with different treatments, the content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) increased in the medium and high concentrations. In addition, the changes in catalase (CAT) and peroxidase (POD) activity were not obvious. Experiments showed that microplastics could significantly inhibit the growth and development of tobacco and reduce the accumulation of aerial parts and root biomass.

Ecological restoration, as a vital means of effectively enhancing the carbon sink function of ecosystems, is currently the subject of active research by scientists. Researchers are actively exploring how to scientifically assess the response mechanisms of ecosystem carbon reservoirs during the process of ecological restoration. In this study, CiteSpace 6.1.(R3 and R6) literature visualization software was employed to conduct data mining on 1566 research articles published from 1996 to 2022, focusing on the impact of ecological restoration on ecosystem carbon reservoirs, as recorded in the Web of Science core database. The analysis involved visualizing various aspects, including the countries involved, research institutions, publication output, research hotspots, and cutting-edge research areas. The research indicates that China holds significant influence in the study of the impact of ecological restoration on ecosystem carbon reservoirs. The literature covers a wide range of research directions and encompasses rich content on the subject matter. The current research focuses on ecological restoration, and its impact on the carbon sink function of ecosystems mainly revolves around four key themes: “the carbon sequestration potential of ecological restoration”, “technological approaches to enhancing the carbon sink function of ecological restoration”, “the importance of assessing carbon sink in terrestrial ecosystems”, and “characteristics of carbon sources/sinks in terrestrial ecosystems”. Currently, the development of research findings on the impact of ecological restoration on the carbon reservoirs of ecosystems is progressing rapidly. Novel research theories, methodologies, and scientific techniques are emerging, necessitating the continuous monitoring and investigation of scholarship in this field. It is crucial to integrate ongoing global environmental-change factors, ensuring the continuity of research and observations and, thus, furnishing robust data support for the assessment and computation of ecosystem carbon sinks.

Multifunctional plant growth-promoting rhizobacteria (PGPR) have garnered significant attention in agricultural applications; however, a few have applied them in crop rotation or intercropping fields. To identify PGPR with strong colonization ability and broad spectrum benefit, we screened strains from the local tobacco rhizosphere and evaluated their growth-promoting effects across various crops and farming systems. In this study, strain L8, identified as Bacillus thuringiensis , was selected as a multifunctional PGPR capable of producing indole-3-acetic acid (IAA), solubilizing potassium, and mobilizing both organic and inorganic phosphorus. Compared with the control group, the soil treated with strain L8 in tobacco pot experiments showed significantly higher levels of IAA, available potassium, and available phosphorus. Furthermore, tobacco plants inoculated with L8 exhibited significantly improved growth parameters compared with the uninoculated control. The results indicated that compared with the control, strain L8 increased tobacco fresh weight (by 83.18%), plant height (by 29.32%), relative chlorophyll content (by 14.33%), as well as plant phosphorus (by 23.78%) and potassium (by 30.81%). Interestingly, L8 not only enhanced tobacco growth but also improved tobacco root morphology, significantly increasing root length (1.55-fold), root surface area (1.78-fold), and root volume (2.05-fold) compared with the control. These findings provide valuable insights into utilizing plant growth-promoting bacteria for tobacco production. Moreover, the inoculation strain L8 enriched soil organic matter and nutrient content in both wheat ( Triticum aestivum )-maize ( Zea mays ) rotation and peanut ( Arachis hypogaea )-maize intercropping systems. Furthermore, within the intricate tillage systems of wheat-corn rotation and peanut-corn intercropping, multifunctional PGPR strain L8 can play a crucial role in crop growth promotion, yield increase, and higher soil nutrient availability. IMPORTANCE: These findings aim to study the application of plant growth-promoting rhizobacteria (PGPR) in diverse crops and complex planting systems, showing their adaptability and effectiveness in various agricultural contexts. The study suggests that this strain improves nutrient utilization in the soil, enhances soil health, and plays a significant role in plant growth through the secretion of substances like auxin (IAA). In parallel, we observed that applying this strain improved the production efficiency of wheat, corn, and peanuts within complex farming systems, indicating that this method holds the potential for enhancing both the yield and quality of various crops.

Poly (butylene-adipate-co-terephthalate) (PBAT) biodegradable mulch film has been considered a promising, environmentally friendly, and sustainable alternative to polyethylene. However, its long-term effects on crops and soil remain insufficiently understood. This study aimed to investigate the effects of PBAT mulch film with three application rates (0.05 g/kg, 0.5 g/kg, and 5 g/kg), as well as polyethylene (PE) mulch film (0.05 g/kg), on lettuce (Lactuca sativa L.) growth and soil microbial communities after 4-year pot experiment. The results indicated that the degradation of PBAT biodegradable mulch film in soil was significantly higher than that of PE. The concentrations of chlorophyll a, total chlorophyll, vitamin C, soluble protein, and nitrate in lettuce significantly increased in high application rates of PBAT mulch film. Soil urease (UR) activity increased with the increase of the PBAT application rates, whereas catalase (CAT) activity decreased. Moreover, the application of PBAT biodegradable mulch film significantly altered the composition of soil bacterial and fungal communities. The relative abundances of the bacterial genus Chujaibacter and Pseudolabrys increased with high PBAT application rates. Beneficial fungi such as Amphinema and Trichoderma showed an increasing trend, while pathogenic fungi exhibited the opposite pattern. These trends were also validated with the functional classification of bacteria and fungi. Overall, our findings suggest that PBAT mulch film application exerts significant effects on the soil micro-ecological environment and crop growth.