The application of biochar to improve the quality of saline soils has attracted widespread attention. However, the impact of saline soil amendments with biochar prepared at different pyrolysis temperatures remains unclear. Therefore, we conducted a two-year (2022–2023) field experiment in the Hetao Irrigation District, China, to evaluate the effects of the biochar pyrolysis temperature (C1: 300 °C, C2: 500 °C, and C3: 700 °C) and application rate (T1: 10 t/ha and T2: 20 t/ha) on the soil quality and maize yield. The results indicated that (1) all biochar treatments significantly decreased the soil bulk density and increased the soil porosity; (2) treatment C3T1 significantly increased the soil moisture content and decreased soil salinity. The C3T2 treatment significantly increased the soil’s organic carbon content, and the soil’s available phosphorus content was greatest in the C1T2 treatment. (3) The maize yield increased linearly with the soil quality index (SQI), which was attributed mainly to improvements in the soil water–salt conditions and increases in the soil organic carbon content. In summary, biochar produced at high pyrolysis temperatures, when applied at a low application rate (C3T1), can result in high corn yields and improve saline soil quality.

We aimed to explore the mineralization characteristics of soil organic carbon(SOC) under different plant species in semi-arid grassland and provide basic soil carbon cycling data. Leymus chinensis, Stipa krylovii Roshev, Artemisia frigida, and Agrophorn cristam (L.) Gaertn were selected as the plant species. Incubation experiment were conducted on SOC mineralization in soil aggregates with particle sizes of > 2, 1–2, 0.25–1, and < 0.25 mm. The cumulative SOC mineralization amount in L. chinensis with a particle size > 2 mm was the highest, exceeding that of A. cristam (L.) Gaertn by approximately 136.14%. S. krylovii Roshev (70.73%), L. chinensis (58.05%), and A. frigida (33.73%) exhibited pronounced promotion effects on mineralization. The potential SOC mineralization of S. krylovii Roshev was the greatest among all species at the same soil particle size. The potential SOC mineralization was highest at a particle size of > 2 mm for all plant types. All plant types increased the SOC mineralization rate and cumulative mineralization in soils with large particle sizes, the mineralization reaction occurred more strongly. Organic carbon cumulative SOC mineralization rapidly increased in all tests during the first 20 days and gradually slowed thereafter.

Considering the importance of soil moisture in hydrological processes, it is crucial to understand the water distribution and time stability of different aerial shrub soils. There are few studies on the soil moisture of aerial vegetation in the northeastern margin of the Tengger Desert. Based on long-term monitoring data from the aerial seeding area in the northeastern margin of the Tengger Desert, the distribution characteristics of soil moisture and the temporal stability of soil moisture were studied. From June to October 2022, the soil moisture monitoring instrument WatchDog was used to monitor the long-term soil moisture changes (0–200 cm) in the four aerial afforestation plots of Hedysarum scoparium, mixed forest land (Hedysarum scoparium dominant species), mixed forest land (Calligonum mongolicum dominant species), and Calligonum mongolicum. The Spearman rank correlation coefficient was used to study the temporal stability of soil moisture in the four plots. Rainfall data were collected through small weather stations. The results show that the average soil water storage of four kinds of aerial shrub land in the study area was the highest in August, and the average soil water storage of different forest lands was different. The soil water content of the surface layer (0–30 cm) fluctuated the most in different months. The variation in soil water content in the shallow layer (30–100 cm) was smaller than that in the surface layer. The fluctuation of soil water content in the middle layer (100–150 cm) and deep layer (150–200 cm) was relatively stable. There was no strong variability in soil moisture content, and the temporal variation coefficient of surface soil moisture was the highest (31.44–39.8%), which showed moderate variability. The temporal variation coefficient of soil moisture in the shallow, middle and deep layers of all kinds of plots was significantly reduced, and the soil moisture stability of different aerial shrub land was the same. Spearman rank correlation analysis showed that the spatial pattern of soil water content in the surface layer (0–30 cm) and deep layer (150–200 cm) was more stable over time, that is, the temporal stability of soil water content was higher, and the temporal stability of soil water content in the middle and shallow layers of different types of shrub land was different. The research results help us to understand the soil hydrological process in the aerial seeding afforestation area in the northeastern margin of Tengger Desert, rationally arrange soil moisture monitoring points, efficiently manage and utilize water resources in the aerial seeding area, and provide a theoretical basis for local vegetation restoration and the optimization of the ecological environment.

Caragana tibetica is a common species in the shrub-encroached desert grasslands of Inner Mongolia, China. Studying its distribution and factors can improve our grasp of shrub-encroached grassland dynamics and aid in regional biodiversity conservation. This study examined eight C. tibetica communities using point pattern analysis to assess the spatial distribution pattern (SDP) and the influencing factors of C. tibetica scrubs. We also propose a new index, i.e., the degree of deviation index (DoDI), to quantify the SDP of scrubs. The results revealed the following: (1) The shrubland of C. tibetica in the study area showed aggregated distribution on the scale of 0–30 m. On the scale of 30–50 m, the degree of aggregation gradually weakened and random distribution appeared. (2) There was not a significant correlation between SDP and environmental factors; however, DoDI showed that habitat heterogeneity had a certain impact on C. tibetica in the study area. Our research indicates that spatial heterogeneity contributes to the SDP of shrub plants in the shrub-encroached grasslands of the Inner Mongolia Plateau, and the use of DoDI enhances the ability to quantify and isolate the role of spatial heterogeneity. This study helps to deepen the understanding of the mechanisms of shrub encroachment formation in grasslands.

Grazing-induced grassland degradation has attracted increasing attention worldwide, with arid desert regions being particularly affected due to their low precipitation and fragile ecosystems. The vegetation degradation caused by grazing in these regions is especially severe. Grazing exclusion has been widely implemented as a management strategy to rehabilitate degraded grasslands; however, its effects on the successional recovery of desert vegetation, particularly herbaceous species, remain insufficiently understood. In this study, we conducted a grazing exclusion experiment in the desert region of western Inner Mongolia, monitoring continuously from 2022 to 2024, to examine the effects of short-term (1–3 years) and medium-term (6–9 years) grazing exclusion on the biodiversity and biomass of herbaceous plants. In addition, we evaluated changes among different plant functional groups (i.e., perennial tall grass, perennial short grass, perennial forb and annual-biennial plant). The main findings of this study were as follows: (1) With increasing period of grazing exclusion, the alpha diversity of herbaceous plant communities first decreased but then increased. Grazing exclusion resulted in a more even distribution of species without altering total species richness. (2) Grazing exclusion promoted an increase in aboveground biomass, although biomass fluctuated across years because of the influences of annual and biennial species. (3) As the duration of exclusion increased, the proportion of perennial species, especially perennial grasses, increased. Notably, perennial tall grasses were observed only in plots that had been excluded from grazing for more than 6 years. Grazing exclusion, in conjunction with climatic factors, serves as the primary driver of the succession of dominant herbaceous plant species, promoting a transition from annual and biennial species to short perennial grasses and eventually to tall perennial grasses. The presence of tall perennial grasses contributed to the relative stability of the plant community under changing environmental conditions. This study enhances our understanding of the response of desert vegetation to grazing exclusion and provides insights into the successional processes that occur in arid grasslands.