Soil microbial entropy (qMB) is the proportion of soil elements within microbial biomass, reflecting microbial resource support capacity and nutrient use efficiency. Its spatial pattern provides the basis for assessing soil ecological functions. However, existing studies are largely limited to local scales and lack comprehensive, high-resolution national predictions, with insufficient understanding of the multifactor-driven mechanisms and future dynamics under climate change. In this study, we collected microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP) data from 1,288 published studies across China and calculated the corresponding qMBC, qMBN, and qMBP. We compared five machine learning models and selected the random forest model with the best predictive performance to map the spatial distribution of qMB. Subsequently, we explored the main drivers of its spatial variation and projected future trends. The results: (1) The mean values of qMBC, qMBN, and qMBP were 2.93

Grassland ecosystems play a crucial role in the global carbon cycle, yet the spatial patterns and drivers of soil organic carbon density (SOCD) across aridity gradients remain insufficiently understood. Here, we used the Carbon Density Dataset of China's Terrestrial Ecosystems (2010s) and applied random forest models to simulate SOCD at two soil depths (SOCD0-20 cm and SOCD0-100 cm) in arid and humid grasslands. We further quantified the contributions of environmental drivers and projected future SOCD dynamics under Shared Socioeconomic Pathways (SSPs). Results showed that SOCD was lower in arid than in humid regions, but due to their vast extent, arid regions contained larger total soil carbon stocks. The 0-20 cm layer accounted for approximately 50% of the SOCD in the 0-100 cm profile. In arid regions, SOCD0-20 cm was mainly controlled by mean annual temperature and soil moisture, while SOCD0-100 cm depended on clay content and total nitrogen. In humid regions, SOCD0-20 cm was strongly influenced by temperature and NDVI, whereas SOCD0-100 cm was regulated by clay and nitrogen. Under future SSP scenarios, SOCD is projected to decline in arid regions but increase in humid regions, indicating an enhanced carbon sink potential. SOCD0-20 cm showed higher variability and lower stability than SOCD0-100 cm. These findings clarify the spatial heterogeneity and depth-dependent controls of grassland SOCD and provide a scientific basis for region-specific soil carbon management, contributing to China's "dual carbon" goals and sustainable grassland policies.

Against the backdrop of continuously increasing global nitrogen (N) deposition, the changes in photosynthetic carbon (C) allocation patterns of desert plants and their underlying mechanisms affecting soil C sequestration remain poorly understood. This study selected two representative species from desert ecosystems: the non-vascular moss Syntrichia caninervis and the vascular ephemeral plant Erodium oxyrhinchum as research subjects. Three N deposition levels were implemented: 0 (N0), 10.0 (N10), and 30.0 kg N ha−1 a−1 (N30), combined with 13C stable isotope labeling technique, to systematically investigate the effects of N deposition on plant photosynthetic C allocation and soil C sequestration. The experiment demonstrated that: (1) Aboveground 13C content in both species decreased significantly with increasing N input (P < 0.05); (2) N deposition significantly promoted photosynthetic C transfer to soil, with soil 13C allocation increasing from 0.8

During periods with no precipitation, desert ecosystem soils periodically absorb air moisture at night to form non-rainfall water inputs (NRWIs), while substantial carbon dioxide (CO2) emissions are typically observed during midday. However, the intrinsic relationship between these periodic NRWIs and the CO2 release phenomenon remains unclear. In this study, we utilized biological soil crusts and employed in situ observation methods during the summer and fall. We also conducted humidity- and temperature-controlled experiments to investigate the effects and potential mechanisms of NRWIs and temperature variations on daily soil CO2 release. We found that soil accumulated NRWIs and soil respiration rates reached their peak values at dawn and midday, respectively, with a lag of 2-4 h between the two. The accumulated NRWIs increased with the development of the crusts across different cover types, however, there was no significant difference in maximum soil respiration rate observed at noon. Notably, the significant release of CO2 at midday was eliminated when the soil NRWIs were suppressed, demonstrating that the NRWIs were the primary determinant of the substantial CO2 release at midday. Furthermore, the soil sucrase activity, dehydrogenase activity, microbial richness, and the Chao1 index of soil microorganisms were significantly higher at noon than at night, indicating that microbial activity was greater during the day compared with at night. Our results confirm that the significant midday CO2 release in desert ecosystems is like a daily "micro-Birch effect" phenomenon induced by NRWIs. This phenomenon may be due to the transition between dormancy and activation of microorganisms mediated by NRWIs. This study demonstrates that NRWIs induce consistent daily pulses of CO2 in desert ecosystems, representing a previously overlooked microbial-driven pathway. Given the extensive coverage of deserts in global terrestrial ecosystems, this mechanism may have implications for carbon cycling and budget estimates in drylands and potentially at broader scales.

Soil CO2 release under winter snow in arid regions significantly impacts the carbon balance. Enzymatic decomposition is believed to be the primary driver of CO2 release, however, continuous snow cover promotes the formation of the hydroxyl radical (•OH). Under snow-covered conditions, whether •OH oxidation constitutes an alternative organic matter decomposition pathway to microbial activity, and how these processes interact, remains poorly understood. In this study, we investigated the differences in the CO2 release rates at various depths in biological soil crusts under snow cover and examined the impacts of microbial activity and •OH oxidation on CO2 release. The findings indicate that snow cover has an insulating effect on soil temperature, and that temperature fluctuations decrease with increasing depth. However, this insulating effect did not significantly alter the relative contribution of different soil layers to CO2 release. The crust layer and the 0-5 cm soil layer are the primary zones of CO2 release, while the 5-10 cm layer contributes less. In addition, prolonged infiltration of snowmelt promotes •OH generation, which may play a significant role in regulating CO2 release during winter. Microbial activity primarily influences CO2 production in the surface layer, whereas CO2 emissions from deeper soil are mainly driven by •OH oxidation. This study highlights that under winter conditions when microbial activity is suppressed, both biotic and abiotic processes contribute to CO2 release across different soil depths. Given that snow cover is widespread in terrestrial ecosystems, •OH-mediated CO2 release from deeper soil may represent a previously overlooked carbon emission pathway.

Phyllosphere microorganisms play a vital role in supporting host plant health and adaptability. Although previous research on the effects of host performance and their phylogenetic associations on phyllosphere microbial communities has predominantly focused on tropical, subtropical, and temperate forestry ecosystems, the responses of these microbial communities to plant phylogeny and functional traits in temperate desert environments remains poorly understood. In this study, we conducted a quantitative analysis of bacterial and fungal community structures in the phyllosphere of 39 plant species from the Gurbantunggut Desert, a typical temperate desert in Central Asia. Variation partitioning analysis revealed that plant phylogeny, leaf physicochemical properties, and leaf morphological characteristics collectively explained the variation in phyllosphere microbial communities. Specifically, these factors accounted for 19.26%, 14.53%, and 2.32% of the variance in bacterial communities, and 11.55%, 8.36%, and 2.19% of the variance in fungal communities, respectively. A significant hierarchical pattern emerged: plant phylogeny > leaf physicochemical properties > leaf morphological characteristics, highlighting the dominant role of plant filtering effects in community assembly. Linear mixed-effects model analysis further confirmed the significant influence of multiple plant attributes, including phylogeny and functional traits, on microbial community structure. Plant-microbe interaction analysis revealed distinct host preferences of microbial taxa across different plant taxonomic levels. Co-evolutionary analysis also indicated a significant phylogenetic association between host plants and their phyllosphere amplicon sequence variants (ASVs). Overall, our findings demonstrate that plant attributes, particularly plant phylogeny and functional traits, are key factors driving the assembly of phyllosphere microbial communities in deserts. This study provides new insights into species coexistence mechanisms in fragile habitats and enhances our understanding of plant-microbe interactions in global desert ecosystem.

Biological soil crusts (BSCs) are essential components of drylands, yet the effects of their development on soil multifunctionality (SMF) and the drivers behind these effects remain unclear. We sampled 11 sites in Northwest China's deserts, representing different successional stages of BSC development (i.e. cyanobacterial, lichen and moss crusts) as well as bare sand areas. We assessed the SMF of the crust layer and underlying soil at various depths (0-2, 2-5, 5-10, 10-20 cm) and also explored the influence of climatic factors (mean annual temperature, aridity, and solar radiation), crust characteristics (compressive strength, roughness, and thickness), and soil properties (pH, electrical conductivity, soil water content) on SMF across these layers. The presence of BSCs significantly enhanced soil nutritional status [soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), ammonia (NH4+-N), nitrate (NO3--N), and available phosphorus (AP)] throughout the 0-20 cm soil depth and increased SMF in the top 0-10 cm. These positive effects intensified with as BSCs progressed from cyanobacterial to lichen to moss stages, but decreased with soil depth. In the crust layer, SMF across all BSC types was positively influenced by our climatic factors. However, as BSCs developed, the negative influence of climatic factors (mainly solar radiation) and soil properties (mainly pH) on SMF decreased, while the positive influence of crust characteristics (mainly thickness) increased. The influence of climate, crust, and soil factors on SMF also decreased with increasing soil depth and varied by BSC type. Further, our findings demonstrate that the BSC development can buffer the negative effects of increased soil pH and solar radiation on SMF while enhancing the positive effects of crust properties, particularly thickness. This highlights the importance of preserving and promoting BSC development to enhance surface soil multifunctionality and mitigate the adverse effects of climate change on dryland ecosystem multifunctionality.

Aridity has serious impacts on the pools, fluxes and processes of terrestrial carbon (C) and nitrogen (N) cycles. Drylands, with high aridity, also being particularly sensitive to global shifts, require accurate estimation of soil organic carbon (SOC) and total nitrogen (STN) pools for a comprehensive grasp of dryland C and N dynamics within the global C and N cycle. Hence, SOC and STN of 2895 soil samples combined with 11 selected environmental covariates were collected from 175 sampling sites in the drylands of China, the spatial distributions of SOC density (SOCD) and STN density (STND) were mapped with best-performing random forest model. SOC0- 100cm and STN 0-100cm stocks were 30.84 and 2.02 Pg, respectively. Mean annual precipitation and soil moisture were identified as the primary drivers of SOCD 0-30cm and STND 0-30cm , while mean annual temperature influenced SOCD 30-50cm and STND 30-50cm , and soil clay content affected SOCD 50-100cm and STND 50-100cm . Future warming is projected to reduce both SOCD and STND, whereas increased precipitation is expected to have a positive effect on both variables in drylands. Under future climate scenarios outlined by the Representative Concentration Pathway, declines in both SOCD and STND are anticipated, with STND exhibiting a more pronounced decrease. A 1.5 degrees C increase in temperature had the greatest effect on SOCD, while a 15 % decrease in precipitation had the greatest effect on STND. In conclusion, the spatiotemporal estimations presented in this study serve as a valuable supplement to existing SOC and STN stock measurements, enhancing our understanding of C and N cycling in drylands. Our findings are instrumental for effective C and N sinks management, providing valuable data for informed decision-making. For example, afforestation in drylands can lead to significant increases in soil C and N stocks. However, In the future, further warming may lead to large losses of soil C and N in drylands.

The characteristics of soil carbon pools across various ecosystems remain uncertain under different Shared Socioeconomic Pathways (SSPs) in China. Here, we conducted a meta-analysis of existing data and integrated machine-learning models to project spatiotemporal changes in soil organic carbon density (SOCD) by 2050 and 2100 under three Coupled Model Intercomparison Project Phase 6 (CMIP6) climate scenarios. For China's terrestrial ecosystems, national average SOCD was 4.08 kg C m2 in the 0-20 cm soil layer and 9.42 kg C m2 in the 0-100 cm layer, with corresponding carbon stocks of 39.18 Pg C and 90.46 Pg C, respectively. Wetlands exhibited the highest SOCD but contributed minimally to total carbon stock due to their limited area, while forests and grasslands served as the dominant carbon reservoirs, particularly in deeper soils. Spatially, SOCD was highest in northeastern China and the eastern Qinghai-Tibet Plateau, and lowest in northwestern arid regions. Climate was the most critical determinant of SOCD in both soil depth, although its explanatory power was relatively weaker for deep SOCD, where soil factors gained prominence. Human activities significantly reduced surface SOCD in forests and grasslands. Future climate change would exacerbate the decline of surface SOCD, particularly in wetlands, posing substantial challenges to achieving the 4 per mil initiative goals.

Soil microbial biomass (SMB) and stoichiometric ratios of carbon and nutrients in microorganisms are crucial to predict biogeochemical and nutrient cycling in terrestrial ecosystems, particularly under global change. Using SMB data from 1,288 studies in China, we mapped the distribution of microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP) and their stoichiometric ratios using the random forest model. The stocks of MBC, MBN, and MBP in the topsoil (0–30 cm) were (mean with 25% and 75% quantiles), , and Tg, respectively; the corresponding stocks in the subsoil (30–100 cm) were Tg C, Tg N, and Tg P, respectively. The mean MBC/MBN, MBC/MBP, and MBN/MBP ratios in the topsoil were estimated to be 10, 29, and 3.9, respectively, and the corresponding ratios in the subsoil were 8.6, 19, and 2.5, respectively. Soil physico‐chemical properties (pH and moisture) are the main direct drivers of SMB and their stoichiometric ratios, while climate (temperature) indirectly affects SMB. Climate indirectly affects SMB by altering soil moisture and substrate availability, the physico‐chemical properties directly shape SMB content through habitat and resource constraints. The Coupled Model Intercomparison Project Phase 6 demonstrated that SMB stocks will increase until 2,100. Under the Shared Socioeconomic Pathway 5–8.5, SMB stocks increased, especially in the topsoil. Our study clarified SMB stocks and microbial stoichiometric ratios for soils up to 1.0 m depth and revealed the main drivers. We assessed SMB density and microbial stoichiometric ratios, compiled databases across climatic regions, and provided recommendations for regional C, N, and P management.

The drying-rewetting of soil can increase the release of greenhouse gases over a short time period and is one of the key pathways for greenhouse gas emissions in many terrestrial ecosystems, particularly in drylands. The mechanisms underlying this pulse of greenhouse gas emissions remain nearly unknown. Here, we conducted simulated soil rewetting experiments using typical cover of dryland soils (bareland, cyanobacteria/lichen-covered soil, and moss-covered soil). The 13C, 15N, and 18O labeling techniques allowed to explore the intrinsic mechanisms of rapid carbon (C) and nitrogen (N) release from the soils following rewetting. We found that the hydroxyl radical (˙OH) was produced after soil rewetting via the rapid activation of microorganisms. The carbon dioxide (CO2) and nitrous oxide (N2O) production strongly decreased after ˙OH removal, whereas the methane (CH4) production was not affected. The synergistic action between ˙OH oxidation and microbial enzymatic reactions increased CO2 production. The ˙OH also stimulated the oxidation of NH4 + to NO3 - and dominated the N2O production. Our results confirm the role of ˙OH in the production of greenhouse gases and indicate that microbially mediated ˙OH oxidation mechanisms are an overlooked key pathway for the emission of greenhouse gases during the soil rewetting. In the context of climate change, the extreme weather-induced drying-rewetting cycles in soils are becoming more frequent, making greenhouse gas emissions via the ˙OH oxidation pathway increasingly important.

The drylands of China cover approximately 6.6x106 km2 and are home to approximately 5.8x108 people, providing important ecosystem services for human survival and development. However, dryland ecosystems are extremely fragile and sensitive to external environmental changes. Land use and land cover (LULC) changes significantly impact soil structure and function, thus affecting the soil multifunctionality (SMF). However, the effect of LULC changes on the SMF in the drylands of China has rarely been reported. In this study, we investigated the characteristics of the SMF changes based on soil data in the 1980s from the National Tibetan Plateau Data Center. We explored the drivers of the SMF changes under different LULC types (including forest, grassland, shrubland, and desert) and used structural equation modeling to explore the main driver of the SMF changes. The results showed that the SMF under the four LULC types decreased in the following descending order: forest, grassland, shrubland, and desert. The main driver of the SMF changes under different LULC types was mean annual temperature (MAT). In addition to MAT, pH in forest, soil moisture (SM) and soil biodiversity index in grassland, SM in shrubland, and aridity index in desert are crucial factors for the SMF changes. Therefore, the SMF in the drylands of China is regulated mainly by MAT and pH, and comprehensive assessments of the SMF in drylands need to be performed regarding LULC changes. The results are beneficial for evaluating the SMF among different LULC types and predicting the SMF under global climate change.

Soil elemental stoichiometry can characterize soil nutrient storage, supply capacity, and limitation. C:N:P stoichiometry is considered an important indicator of soil nutrient status during soil development. Drylands are critical terrestrial environments and are considered to be the largest biome on Earth. Our study aimed to investigate the C:N:P stoichiometric characteristics and drivers of surface soil in the drylands of China. Our study was conducted based on soil nutrient data derived from the National Tibetan Plateau Data Center and environmental data. We used structural equation modeling, variation partitioning analysis, redundancy analysis, and other methods to investigate whether there are spatial patterns and interrelationships among soil C, N, P, and C:N:P in the drylands of China and to analyze the drivers influencing the changes in C, N, P, and C:N:P. Similarly, C, N, and P density of the surface soil in the drylands of China were low (3.44, 0.14 and 0.10 kg/m2, respectively). Highly significant non-linear relationships were observed between all the nutrients and their corresponding stoichiometric ratios, except for C and P, which exhibited significant linear relationships. Aridity and plant (vegetation) were the main drivers of soil C and N density in drylands, while the main driver of P density was aridity; the soil environment contributed most to the relative changes in C, N, P, and C:N:P. In conclusion, the soil C, N, and P densities in the drylands of China were low. Plant, climate, and soil together explained 47.5–81.3

Biological soil crusts(BSCs)are the main active groundcover community in arid regions.BSCs can significantly affect the material cycle and energy exchange,improve the physical,chemical,and biological prop-erties of surface soil,and influence the soil multifunctionality(SMF).Moss crust is an important type of BSCs.This study investigates the SMF variability of moss crust-covered and bare sand in the deserts of northwestern ar-id regions,and explored the main drivers of the variability.We analyzed eight crucial ecosystem function indica-tors.SMF was calculated by applying the mean method and factor analysis approach.We used the ordinary least square and structural equation modeling to explore the drivers of SMF changes.The results show that:(1)soil monofunctionality and SMF under moss crust cover were higher than those in bare sand(P<0.05).(2)The drivers of the SMF change in bare sand and under moss crust cover were very different.The main drivers of SMF in bare sand were aridity and soil water content,whereas the driver of SMF under moss crust cover was soil sand content(Sand).(3)The mean annual temperature had the largest indirect effect on changes in SMF for both soil in bare sand and under moss crust cover.Therefore,the development of moss crust significantly increased SMF and,in addition,modulated the relevant drivers of SMF.Our results are important for a deep understanding of the differ-ences and drivers of SMF in desert soil with bare sand and under moss crust cover.

甲烷(CH4)和氧化亚氮(N2O)等温室气体通量具有高度时空变化特点,通过野外站点直接测量耗时且费力.为弥补监测方面不足,解析变化环境下反硝化-分解模型(DNDC)模拟值和样地原位观测值之间的对应关系,探讨模型在温室气体预测方面的潜力具有意义.本文选择古尔班通古特沙漠,对氮沉降影响下荒漠土壤CH4和N2O通量进行了模拟估计,并与实测数据进行了对比分析.结果表明:DNDC模型可较好地模拟荒漠土壤N2O通量的变化,模拟值与实测值显著相关(P＜0.001);而模型对荒漠土壤CH4吸收量的变化模拟效果不显著,但模拟的年累计吸收量与真实值较为符合.DNDC模型敏感性试验分析表明,随着年平均气温、土壤有机碳(SOC)含量和施氮量的增加,土壤N2O排放量和CH4的吸收量显著增加;年降水量对土壤N2O和CH4通量变化影响不显著;土壤容重与土壤N2O排放量和CH4吸收量显著负相关;土壤质地对两种温室气体排放的影响显著,其中砂壤土影响最大.多元回归分析表明温度是荒漠土壤N2O和CH4的通量变化最重要影响因素.因此,在全球变化背景下,尽管模型目前运用于荒漠区还存在一些问题,但在将来荒漠区温室气体通量的变化估算方面仍具有很强的应用价值.

This study was conducted to analyze the variation of soil multifunctionality (SMF) along elevation and the driving factors in the Altun Shan. Soil samples (0–10 cm) were collected from 15 sites (H01 to H15) at every 200 m elevation interval, covering a total range from 900 m to 3500 m above mean sea level. We investigated climate factors (mean annual temperature, MAT; mean annual precipitation, MAP), soil environment (soil water content, electrical conductance, and pH), vegetation factors, and elevation to determine which of them are the main driving factors of the spatial variability of SMF in the Altun Shan. We explored the best-fit model of SMF along the changes in elevation using a structural equation model, performed variance partitioning analysis (VPA) on SMF with the “varpart” function to explain the relative contribution of various environmental factors to SMF changes, and used a random forest model for relative importance analysis. The results showed that SMF in the Altun Shan significantly increased with elevation in a linear trend. The main driver of changes in SMF was found to be MAP. Although the rise in elevation did not have a significant direct effect on changes in SMF, it could indirectly affect SMF by significantly influencing MAP, pH, MAT, and normalized difference vegetation index (NDVI). When considering climate, soil environment, and vegetation factors together, they explained 76% of the variation in SMF. The largest contribution to the variation in SMF was attributed to the independent effect of climate (0.31) and its interactive effect with soil (0.30). The relative importance of MAP on SMF changes was found to be the greatest. It is indicated that changes in SMF are caused by the combined effect of multiple environmental conditions. These findings are essential for understanding the spatial variability and drivers of SMF in dryland mountain ecosystems, especially concerning the function of mountain ecosystems in the context of global climatic changes.

Background Considerable attention has been given to how different aspects of biodiversity sustain ecosystem functions. Herbs are a critical component of the plant community of dryland ecosystems, but the importance of different life form groups of herbs is often overlooked in experiments on biodiversity-ecosystem multifunctionality. Hence, little is known about how the multiple attributes of diversity of different life form groups of herbs affect changes to the multifunctionality of ecosystems. Methods We investigated geographic patterns of herb diversity and ecosystem multifunctionality along a precipitation gradient of 2100 km in Northwest China, and assessed the taxonomic, phylogenetic and functional attributes of different life form groups of herbs on the multifunctionality. Results We found that subordinate (richness effect) species of annual herbs and dominant (mass ratio effect) species of perennial herbs were crucial for driving multifunctionality. Most importantly, the multiple attributes (taxonomic, phylogenetic and functional) of herb diversity enhanced the multifunctionality. The functional diversity of herbs provided greater explanatory power than did taxonomic and phylogenetic diversity. In addition, the multiple attribute diversity of perennial herbs contributed more than annual herbs to multifunctionality. Conclusions Our findings provide insights into previously neglected mechanisms by which the diversity of different life form groups of herbs affect ecosystem multifunctionality. These results provide a comprehensive understanding of the relationship between biodiversity and multifunctionality, and will ultimately contribute to multifunctional conservation and restoration programs in dryland ecosystems.

Background Multiple components of biodiversity are excellent predictors of precipitation-induced changes in ecosystem function. However, the importance of differing scales (alpha versus beta) is usually overlooked in biodiversity–ecosystem multifunctionality studies. Consequently, little is known about how precipitation regulates the relationship between multifunctionality and multiple components of alpha and beta diversity. Aims We investigated geographic patterns of herbaceous plant diversity and ecosystem multifunctionality along a precipitation gradient spanning more than 2010 km in Northwest China. Methods We assessed the effects of herbaceous species, phylogenetic, and functional components at different scales on multifunctionality in drylands. Results The alpha diversity of species and functional beta diversity were key components explaining the variation in multifunctionality. As the main environmental factor, MAP (mean annual precipitation) affected multifunctionality by changing the mediating variables (i.e., species alpha and functional beta diversity). More importantly, a certain precipitation threshold was detected for the relationship of multifunctionality to species alpha and functional beta diversity. MAPs of approximately 158 mm and 140 mm modulated this relationship (shifting it from uncorrelated to significantly correlated). Conclusions Our findings provide insights into previously neglected mechanisms by which diversity in herbaceous layers at different scales affects ecosystem multifunctionality. It is highlighted that MAP regulates the relationship between diversity and multifunctionality in dryland ecosystems at different scales. Further, diversity may have substantial consequences for multifunctionality where MAP is higher. These empirical results provide a comprehensive understanding of the biodiversity–multifunctionality relationship in the context of precipitation, ultimately contributing to conservation and restoration programs for multifunctionality in drylands.

The drylands of China account for about 10.8

Aims:This study was conducted to analyze the soil multifunctionality (SMF) pattern and their driving factors of the Junggar Desert.We tested that whether climate factors (temperature, precipitation and Aridity), soil environment (soilwater content, soil temperature and pH) and vegetation factors would be the main driving factors of the spatial variability of SMF in the Junggar Desert.Methods: The data of the sampling were collected from 79 sample sites of the Junggar Desert.The SMF indices were calculated by mean method and factor analysis method.The spatial characteristics of SMF in the Junggar Desert were obtained by using Kriging interpolation method in ArcGIS.Correlation analysis between single soil function and SMF was performed in R language software, and the best-fit model was used to fit the environmental factors and SMF of the 79 sample sites.The best-fit model was selected applied on the R 2 and the AIC value of the model.Structural equation model (SEM) analysis was performed using the "Lavaan" package in R language.Direct and indirect effects of different variables on SMF were identified, and the driving factors of spatial variability of the SMF in the Junggar Desert were determined.Results: Overall, the SMF in the Junggar Desert showed large heterogeneity in spatial distribution, with an increasing trend of SMF from west to east, and trend of increasing first and then decreasing from south to north of the desert.The best-fit model showed that SMF had a significant quadratic function with MAP (mean annual precipitation) and MAT (mean annual temperature), and showed a decreasing first and then increasing trend of with the increase in MAP and MAT.The SMF had a significant primary function with pH and EVI (enhanced vegetation index).Specially, SMF had a trend of significant decreasing along with the increase in pH, and a significant increasing trend along with the increase in EVI.The SMF and Aridity (drought) showed both quadratic and linear (R 2 was the same for both) relationship, with SMF decreasing with the increase in Aridity.The results of structural equation modeling (SEM) indicated that, SWC was the most important driver of SMF change, followed by EVI.Soil pH, SWC (soil water content), MAT, Aridity and EVI had significant direct effects on SMF in the desert area, with SWC and EVI having significant positive effects and the others having negative effects.MAP, Lon (longitude), Lat (latitude) and Alt (altitude) had indirect effects on SMF by affecting factors such as MAT. Conclusion:The results of this study indicate that the changes in SMF are caused by the combined effect of multiple environmental conditions.The results are important for the in-depth understanding of the spatial pattern and driving factors of the SMF in the Junggar Desert, which will be beneficial for the assessment of the effects of environmental changes on the multifunctionality and for the ecosystem managements of the desert ecosystems.