Green manure (GM) boosts sustainable agriculture by enhancing soil fertility and crop yields. However, the dynamics of nitrogen (N) release from different GM residues into soil and their supply patterns to wheat remain unclear. Clarifying residue N mineralization during the growing season and its contribution to soil N fractions and wheat is key to optimizing GM use strategies. An in-situ decomposition experiment using 15N-labeled soybean (SB) and sudangrass (SG) GM was conducted in a wheat field on the Loess Plateau. Soil and wheat samples were collected at different wheat growth stages. We determined GM-N mineralization, wheat N uptake, and yield at maturity. The contribution and recovery rate of residue N to soil total N (STN), particulate organic N (PON), microbial biomass N (MBN), available N (NH4⁺ and NO3⁻), and to the wheat were also measured. Our results showed that the GM-N mineralization rate and amount from SB consistently exceeded those from SG throughout the wheat growth stages. At maturity, compared to the CK, SB and SG treatments increased wheat N uptake by 112% and 47%, and yield by 65.30% and 39.09%, respectively. The contribution of SB-N to wheat was 8.23 times greater than that of SG. During the wheat season, SB exhibited higher soil N distribution and recovery rates than SG. Before green-up, SB showed greater distribution and recovery rates in PON and MBN than SG. However, during jointing and heading stages, SG demonstrated higher recovery rates in PON and MBN than SB. SB residue N was predominantly accumulated in PON and MBN pools in the early growth stage, which may act as transient N reservoirs and potentially contribute to subsequent wheat N uptake. In contrast, SG’s contribution was more consistent with direct N mineralization supplying available N. Correlation analysis revealed a positive relationship between GM-N contributions to soil N fractions and wheat N uptake, which was closely associated with yield formation. Legume residue N is initially retained in PON and MBN pools, and may subsequently contribute to plant N supply during peak wheat demand after green-up, thereby showing greater temporal synchrony. In contrast, the asynchrony of the non-legume residue N supply may be partly explained by intense early-stage microbial N immobilization competition and limited storage in soil organic N. This demonstrates the greater potential of legume GM for enhancing soil fertility and crop yields.

Soil fungi constitute multiple functional communities essential for organic matter decomposition. Cover crops stabilize sustainable crop production by introducing exogenous organic matter to mitigate chemical fertilization-induced soil degradation. But responses of wheat growth to soil characteristics and fungal functionality communities under combined impacts of cover crop and nitrogen fertilization were not obviously elucidated. Herein, the long-term interactive experiments of cover crop and nitrogen fertilization revealed that cover crop increased soil organic carbon by an average of 18% and increased soil mineral-associated organic carbon by 13%, while fertilization increased them by an average of 8% and 7%, respectively. Legume cover crop reduced soil bulk density by 7%-8%, but increased soil water content by 8%-31% among distinct fertilizations. Soil fungal functional communities were mainly composed of the saprotroph communities, their diversity generally had the highest values in the middle fertilization in each cover crop. Meanwhile, cover crop and fertilization singly and interactively had stronger effects on the pathotroph and symbiotroph community compositions, respectively. Stochastic processes governed the saprotroph and pathotroph communities, while deterministic processes intensified along with elevated fertilization. Networks of soil fungal functionality communities were composed of specialized modules consistently containing diversified trophic mode phylotypes. Overall, wheat growth indicated by wheat biomass and grain yield was enhanced by optimal fertilization rate in legume cover crop. Moreover, wheat growth was primarily regulated by the direct effects of pathotroph community composition and the total effects of fertilization and soil characteristics based on partial least squares path modeling. These findings suggest that optimal combinations of cover crop and nitrogen fertilization can benefit crop production through regulating soil characteristics and fungal functionality communities, which likely serves as a valuable reference for cover crop agricultural system to balance the management of cover crop and nitrogen fertilization.

Microbial dormancy is a fundamental ecological strategy that governs soil microbial persistence, functional stability, and the capacity of microbial communities to respond to environmental change. However, how agricultural management practices influence the soil microbial dormancy remains insufficiently understood. To address this knowledge gap, we conducted a long-term field experiment involving three nitrogen fertilization levels and four cover crop treatments to evaluate their effects on soil microbial dormancy. Random forest and variance partitioning analyses were used to identify the key environmental drivers of microbial dormancy. Our results demonstrated that that nitrogen fertilization reduced the soil microbial dormant fraction, with a significant decrease observed under N120 treatment (120 kg N ha−1), where dormancy declined by 7.3

Soil microbial heterotrophic respiration (HR), a crucial carbon flux to the atmosphere, is closely related to microbial community traits. However, community level microbial traits associated with such process remain understudied across forest biomes. Here, we accessed microbial traits influence on HR across a forest climatic gradient in China. We found that microbial HR showed distinct differentiation along an environmental gradient, which were highest in temperate forest Maoer mountain (1067.95 mg C kg−1) and lowest in tropical forest Xishuangbanna (178.83 mg C kg−1). At the community level, microbial HR was tightly related to microbial biomass and composition, and genomic traits. Notably, the HR was positively correlated with guanine-cytosine base pair content, but negatively correlated to the average 16S rRNA copy number and the average genome size of microbes (P < 0.05). Moreover, among the forests, soil organic carbon and alkyl-C/O-alkyl-C ratio were the crucial variables in explaining HR, which attributed to their effects on microbial composition and genomic traits. Overall, microbial genomic traits at the community level play an important role in understanding HR. Our findings elucidate new evidence on the mechanisms driving soil carbon fluxes and enhance predictions of soil carbon responses to future climatic change.

Long-term manure application has the potential to alleviate soil acidification, and increase carbon sequestration and nutrient availability, thus improving cropland fertility. However, the mechanisms behind greenhouse gas N2O emissions from acidic soil mediated by long-term manure application remain poorly understood. Herein, we investigated N2O emission and its linkage with gross N mineralization and nitrification rates, as well as nitrifying and denitrifying microbes in an acidic upland soil subjected to 36-year fertilization treatments, including an unfertilized control (CK), inorganic fertilizer (F), 2x rate of inorganic fertilizer (2F), manure (M), and the combination of inorganic fertilizer and manure (FM) treatments. Compared to the CK treatment (1.34 mu g N kg-1 d-1), fertilization strongly increased N2O emissions by 34-fold on average, with more pronounced increases in the manure-amendment (10.6-169 mu g N kg-1 d-1) than those in the inorganic fertilizer treatments (3.26-5.51 mu g N kg-1 d-1). The manure amendment-stimulated N2O emissions were highly associated with increased soil pH, mean weight diameter of soil aggregates, substrate availability (e.g., particulate organic carbon, NO3-and available phosphorus), gross N mineralization rates, denitrifier abundances and the (nirK+nirS)/nosZ ratio. These findings suggest that the increased N2O emissions primarily resulted from alleviated acidification, increased substrate availability and improved soil structure, thus enhancing microbial N mineralization and favoring N2O-producing denitrifiers over N2O consumers. Moreover, ammonia-oxidizing bacteria (AOB) rather than ammonia-oxidizing archaea (AOA) positively correlated with soil NO3-concentration and N2O emissions, indicating that nitrification indirectly contributed to N2O production by supplying NO3-for denitrification. Collectively, manure amendment potentially stimulates N2O emissions, primarily resulting from alleviated soil acidification and increased substrate availability, thus enhancing N mineralization and denitrifier-mediated N2O production. Our findings suggest that consideration should be given to the greenhouse gas budgets of agricultural ecosystems when applying manure for managing the pH and fertility of acidic soils.

Particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) are two operationally defined fractions frequently used in studies related to soil organic carbon (SOC) dynamics. However, the changes and governing mechanisms of these fractions, particularly along a restoration chronosequence, remain poorly understood. Here, we investigated changes in SOC fractions, soil properties, and microbial communities across a restoration chronosequence (1, 5, 7, 13, and 20 years) of alpine meadows using a space-for-time substitution approach on the Qinghai-Tibet Plateau. We quantified the contributions of biotic and abiotic drivers using Spearman correlation analysis, linear regression and random forest analysis. The results revealed a unimodal pattern in SOC, POC, and MAOC contents, peaking at 7, 5, and 7 years, respectively, with no further increase thereafter. Restoration duration strongly shaped microbial community structure and observed species richness, but had no significant effect on Shannon index and Pielou index. Random forest analysis identified soil water content (SWC) and total nitrogen (TN) as the primary predictors of SOC. The microbial community composition dominated the variation in POC while enzyme activity was the key driver of MAOC. Our findings highlight that soil carbon accumulation during alpine meadow restoration is a nonlinear process with a temporal threshold, and POC and MAOC are regulated by distinct biotic and abiotic mechanisms. This study provides a theoretical basis for understanding carbon sequestration mechanisms during alpine meadow restoration and developing sustainable grassland management strategies.

Urban green spaces (UGS) are vital for mitigating the urban heat island (UHI) effect, yet the specific contribution of tree species diversity to cooling efficiency across different UGS types and seasons remains insufficiently quantified, especially in semi-arid regions. This study integrates multi-temporal Landsat-8 and Sentinel-2 imagery during 2021-2022 with field-based ecological surveys conducted in 2021 to evaluate how tree diversity regulates the cooling performance of urban green spaces in Xi'an, China. Using downscaled 10-m land surface temperature (LST), cooling effects were quantified using temperature-drop amplitude (TDA) and cooling range (CR). Results show that park green spaces exhibit the strongest cooling capacity (annual mean TDA: 1.06 degrees C; CR: 229 m), significantly outperforming community and street green spaces. Tree-species richness, measured by the Patrick index, shows a strong positive association with cooling intensity (TDA; P < 0.001). Multivariate analysis further demonstrates that the cooling benefit of diverse tree communities is mainly via enhance canopy density. Seasonal variation emerges as the dominant control on cooling performance, with peak effects observed in summer and minimal cooling in winter. At the annual scale, water coverage and season are the most influential factors regulating cooling intensity (R-2 = 0.69), followed by vegetation coverage, while impervious and bare surfaces suppress cooling effect. Notably, building density within a 105-m buffer shows a positive contributing to cooling intensity. Overall, the findings demonstrate that beyond expanding green-space area, optimizing tree species composition and land-cover configuration is essential for strengthening UGS cooling performance.

Dormancy, as a microbial survival strategy, plays a crucial role in sustaining microbial diversity. However, the large-scale distribution patterns of microbial dormancy and drivers remain poorly understood. Here, we analyzed 591 soil samples from 197 field sites across China, spanning deserts, croplands, grasslands, and forests, to quantify the proportion of dormant microbial cells (Dormancy%). On average, 95.48% of soil microbial cells were dormant, with the lowest Dormancy% in forests (93.84%) and the highest in deserts (96.81%). This regulation followed a regular mechanism: soil water-holding capacity and beta-1,4-glucosidase activity acted as immediate triggers, while mineral-associated organic carbon, dissolved organic carbon and microbial biomass carbon indirectly governed the process. Overall, this study provides evidence at the China scale for the dominance of dormant microorganisms in terrestrial ecosystems and reveals the environmental regulatory mechanism of dormancy, highlighting its ecological importance for maintaining microbial diversity and ecosystem stability.

Intrinsic water-use efficiency (IWUE), a crucial physiological parameter derived from tree-ring stable carbon isotope ratios (13C/12C), offers vital insights into long-term forest adaptation strategies under changing environmental conditions. In this study, we established chronologies of tree-ring width, basal area increment (BAI), stable carbon isotope (δ¹³C), stable carbon isotope discrimination (Δ¹³C), and IWUE for Pinus tabulaeformis from 1901 to 2023 in the Yanshan Mountain region. Correlation analyses revealed a robust positive relationship between BAI and the self-calibrating Palmer Drought Severity Index (scPDSI). Additionally, a significant negative correlation was observed between the Δ¹³C series and mean maximum temperature. During the study period, the IWUE exhibited an increase of approximate 55.56%. Linear regression analysis revealed that the primary driver of the secular trend in IWUE is the rise in atmospheric CO₂ concentration (Cₐ), accounting for 97% of the observed variance. Additionally, interannual fluctuations in IWUE were primarily influenced by changes in average maximum temperature. The Pinus tabulaeformis ecosystem exhibited a positive response to increased Cₐ leading to enhanced carbon sequestration. However, despite this physiological adaptation, the rise in IWUE was inadequate to counteract the detrimental effects of concurrent climatic warming on radial growth. This observation highlights a notable decoupling between IWUE and tree radial growth amid ongoing regional climate change.

Abstract Microbial necromass carbon (MNC) is an important component of the soil carbon sink in alpine meadows on the Qinghai-Tibet Plateau. However, we still know little about how soil properties and the microbial community regulate MNC during ecosystem restoration. This study examined the temporal dynamics of MNC components (bacterial and fungal) and microbial network stability across a 20-year restoration chronosequence (1, 5, 7, 13, and 20 years). The contents of bacterial necromass carbon (BNC), fungal (FNC), and total MNC increased rapidly during the early restoration phase, peaking at 7 years, followed by a decline in later stages. At this peak stage, bacterial network stability reached a relatively high level, in contrast to significantly lower fungal network stability. Random Forest modeling identified soil water content, particulate organic carbon, soil organic carbon, and total nitrogen as dominant abiotic predictors of MNC. Biotically, fungal network stability was a key determinant, showing a significant negative correlation with MNC accumulation. This pattern was linked to the dynamics of ectomycorrhizal fungi. Collectively, these results reveal that MNC sequestration is jointly regulated by soil resource availability and fungal community stability, providing new insights into the microbial mechanisms underlying soil carbon recovery in restored alpine ecosystems.

Management practices, including cover cropping and nitrogen fertilization, are widely recognized to influence agricultural soil multifunctionality (SMF). However, how their effects vary across different management durations, and the underlying mechanisms, remain poorly understood. To address this, we conducted a seven-year field experiment on the Loess Plateau, comparing the effects of cover cropping and nitrogen fertilization on SMF under short-term (4-year) and long-term (7-year) management. Our results show that long-term management significantly enhanced SMF by 57.5% compared to short-term management (p < 0.05). This increase in SMF was associated with a significant reduction in both bacterial and fungal diversity under long-term management (p < 0.05). At the same time, shifts in microbial community composition were observed, including increased relative abundances of keystone taxa such as Ascomycota and Actinobacteria. Collectively, our results suggest that long-term management enhances SMF relative to short-term management despite reduced microbial diversity, indicating that factors beyond diversity, such as shifts in community composition, may contribute to the maintenance of multifunctionality. This insight provides a practical foundation for designing sustainable agricultural soil management strategies aimed at optimizing soil health and ecosystem functioning.

Microbial necromass nitrogen (MNN) is a dominate component of soil organic N, and its management has emerged as a promising strategy for sustaining N reservoir and maintaining soil fertility. However, the effects of fertilization practices on MNN accrual and their driving factors remain unclear at broad geographic scales, limiting the development of effective strategies for sustainable soil N management. Through a large-scale soil survey across 11 long-term fertilization experimental sites spanning diverse soil types and climatic conditions in croplands of eastern China, we found that MNN content significantly increased by 7-85% under chemical fertilization, 37-120% under straw return, and 6-220% under manure application. Fertilization-induced increase in MNN was primarily driven by exogenous N fertilizer inputs and inherent soil clay content. N fertilizer inputs significantly enhanced the availability of soil carbon and N, thus promoting microbial biomass and MNN formation. Conversely, the positive effect of N fertilization on MNN accumulation was weakened with increasing soil clay content, mainly due to the relative limitation of fungal growth and enhanced MNN mineralization in high-clay soils. These findings suggest that increasing N inputs in high-clay soils may constrain MNN accumulation and increase the vulnerability of soil N stabilization, underscoring the need to prioritize organic resource allocation to coarse-textured soils to maximize MNN storage and improve soil fertility.

The terrace-ditch-pond (TDP) system is a typical structural unit regulating agricultural non-point source pollution. Elucidating nitrate sources, transport pathways, and transformation processes in the system is crucial for formulating effective source control measures. However, how precipitation–driven hydrological connectivity governs nitrate drainage pathways and their relative contributions to downstream nitrate inputs remains poorly understood. This study quantitatively characterized nitrate transport, transformations, and source contributions in the TDP system by integrating hydrological–hydrochemical analyses, Bayesian stable isotope mixing modeling (MixSIAR), and structural equation modeling (SEM). Nitrate composition in the TDP system exhibited significant spatiotemporal heterogeneity. During the low-flow (LF) season, direct drainage from terraces was the main input pathway for pond nitrate (42.2%), with fertilizers being the primary nitrate source (49.0%), highlighting the influence of agricultural fertilization. During the high-flow (HF) season, heavy precipitation enhanced the hydrological connectivity of ditches, making indirect drainage from ditches the main nitrate input pathway (53.2%), with nitrate primarily derived from manure and sewage (40.7%) and soil nitrogen (40.8%). Nitrification predominated in both hydrological conditions, whereas localized denitrification was significantly intensified under high-flow conditions. These findings demonstrate that precipitation-driven hydrological pathways restructure nitrate sources, transport routes, and biogeochemical transformations in the TDP system, offering a robust basis for precise source tracing and season-specific management of agricultural non-point source pollution.

Despite the widely recognized importance of grassland restoration for soil multifunctionality (SMF), its temporal dynamics along the restoration chronosequence and the relative contributions of bacterial and fungal diversity to SMF remain poorly understood, particularly in alpine grasslands. Here, we examined SMF along an alpine grassland restoration chronosequence (1, 5, 7, 13, and 20 years) on the Qinghai-Tibet Plateau. We found that SMF exhibited a pronounced non-linear trajectory, increasing by 39.13% from year 1 to year 7, subsequently declining by 50% and 46.88% at years 13 and 20, respectively, relative to the peak at year 7. Fungal richness varied markedly across the restoration chronosequence, peaking in year 5 with a 16.03% increase relative to year 1, and was positively associated with SMF, whereas bacterial richness showed no significant relationship. Structural equation modeling further confirmed that, along with soil moisture, fungal richness was significantly associated with SMF. Together, our findings highlight fungal diversity as a key driver of SMF during alpine grassland restoration and improve process-based predictions of alpine grassland functioning under ongoing climate change.

Precipitation use efficiency (PUE) and soil water use efficiency (SWUE) are key indicators of the carbon-water cycle in terrestrial ecosystems. Yet in water-limited regions, the spatial patterns and driving mechanisms of this cycle, shaped by precipitation and soil moisture, are still poorly understood. This study used an improved twoleaf model with modified environmental stress factor expressions to simulate gross primary production (GPP) on the Loess Plateau from 2001 to 2023, then calculated PUE and SWUE by integrating precipitation and soil moisture data. To investigate the spatial dynamics and driving mechanisms of these indicators, we used linear regression, Mann-Kendall tests, XGBoost, and residual analysis. The results show that the improved two-leaf model's simulations closely match observations, reducing root mean square error by 21.8%. Both PUE and SWUE have exhibited an increasing trend, with 64.34% of the area showing simultaneous increases, and the multi-year average exhibiting a gradient shift from northwest to southeast. Compared with other vegetation types, cropland shows the highest annual mean PUE and SWUE, with the greatest rate of change occurring in cropland reclamation areas. PUE and SWUE are influenced by multiple factors. Precipitation and the aridity index carry relatively high weights in controlling PUE, whereas soil moisture is the primary environmental determinant of SWUE, and its influence increased markedly from 2001 to 2023. Moreover, human activities have a greater impact on both PUE and SWUE than climate change. These findings provide scientific guidance for vegetation restoration and water-resource management in arid and semi-arid regions.

Straw return has been widely used as a key measure to increase carbon (C) sequestration and sustain crop yields on the North China Plain, however, its effects were limited under long-term application. The mechanisms underlying the transformation of residue-derived C in soil and saturation status of different protected pools following long-term different straw return levels remain unclear. Soil samples were collected from a 41-yr field experiment with varying straw return rates: 0 kg.ha-1 (CK), 2250 kg.ha-1 (S1), 4500 kg.ha-1 (S2), and 9000 kg.ha-1 (S3), and incubated with 13C-labeled straw for 300 days. Soil organic carbon (SOC) and its active fractions in different C pools were measured. After 300 days of incubation, SOC concentration (14.2 %-26.1 %) and active C fractions (32.8 %-220.5 %) increased with an increase in straw application rates. Residue-derived particulate organic C (POC), microbial biomass C (MBC), and dissolved organic C (DOC) concentrations were greater in S3 than in S1 and S2, and these values were greater in S2 than in S1. Furthermore, straw return increased SOC concentration in different protected pools by 4.2 %-36.0 %, but no significant differences were found between S2 and S3 for all protected pools. Residue-derived C was primarily stored in the unprotected pool, accounting for 73.9 %-80.8 %. The residue-derived C concentration in S3 was significantly higher than those in S1 and S2 (except for the microaggregate-protected organic C and occluded silt and clay fractions). All protected pools showed signs of C saturation, but the mechanisms of C saturation differed. The physically protected pool reached C sequestration limit due to microaggregate restrictions. In contrast, the chemically and biochemically protected pools reached a steady-state balance through the mineralization loss of native SOC and the fixation of residue-derived C. Overall, after long-term straw return in North China, surface soils still retain C sequestration potential, but no significant differences in C sequestration were observed between medium and high rates of maize straw return. Integrating straw return with targeted nutrient management or diversified planting is essential to enhance the C sequestration capacity of straw return in the long run.

While manure application is crucial for maintaining soil fertility, it may pose a risk to public health by promoting the spread of antibiotic resistance genes (ARGs). Nevertheless, the long-term effects of fertilization practices on the accumulation and dynamics of ARGs remain poorly understood. We employed metagenomic sequencing to investigate changes in soil ARGs and bacterial communities and to identify factors influencing these dynamics in a 35-year field fertilization experiment. Four treatments were included as chemical nitrogen fertilizer (N), manure (M), chemical nitrogen plus manure (NM), and control with no fertilization (CK). Both M and NM treatments significantly increased the abundance of ARGs and bacterial communities, while also shifting their profiles in the soils. Strong and significant correlations between ARGs and bacterial communities were observed through network analyses. Dominant bacterial phyla (Proteobacteria, Actinobacteria, Firmicutes, Nitrospirae, Gemmatimonadetes, and Acidobacteria) were identified as ARG hosts. Co-occurrence network analysis and random forest models detected several key ARGs, which were classified into two principal mechanisms: antibiotic efflux (mdtP, mtrC, and mexN) and antibiotic target alteration (PmrB, arnA, aminocoumarin resistant cysB, Sser_parE_FLO, Ngon_parC_FLO). Soil organic carbon and total nitrogen were the dominant soil properties influencing ARG abundance. Furthermore, these soil properties indirectly affected ARG abundance by shaping the abundance of bacterial communities. Altogether, our results provide insights into the role of long-term fertilization in regulating ARG distribution in the soils and highlight potential risks associated with the external introduction of manure-derived ARGs from fertilization practices, particularly the potential transfer of resistance genes to plants.

Agricultural terrace-ditch-pond (TDP) systems are common connected drainage units in hilly agricultural regions, where terraces, ditches, and ponds jointly regulate runoff and nutrient transport. Although nitrate sources and catchment-scale runoff export have been widely studied, the relative contributions of direct terrace drainage and indirect ditch drainage to pond nitrate remain insufficiently quantified in TDP systems. To address this gap, a representative TDP system in Guang'an, Sichuan Province, China, was investigated from April to July 2023, and a pathway-level TDP framework was established. Hydrochemical analyses, a Bayesian stable isotope mixing model (MixSIAR), and structural equation modeling (SEM) were integrated to examine coupled changes in nitrate source apportionment, pathway contributions (including concentration-based and load-based contributions), and transformation under contrasting rainfall conditions. During low-flow (LF) conditions, direct terrace drainage was the dominant concentration-based pathway contributing to pond nitrate (42.3%), with fertilizer as the primary nitrate source (49.0%). During high-flow (HF) conditions, indirect ditch drainage became the dominant concentration-based pathway (53.2%), accompanied by increased contributions from manure/sewage and soil nitrogen. This pathway shift was also consistent with CB-SEM results and with load-based results showing higher TN and NO3⁻-N loss loads along the direct terrace drainage during LF but along the ditch pathway during HF. PLS-SEM indicated coordinated responses among precipitation intensity, DIN, and nitrate transport and transformation indicators. Integrated isotope, hydrochemical, and SEM evidence further suggested that increased rainfall may enhance ditch nitrate transport while also being associated with localized transformation signals. This study offers a pathway-level framework for interpreting nitrate source-pathway relationships in TDP systems and may help inform rainfall-responsive management of agricultural drainage networks.

The dynamic variation of vegetation net primary productivity (NPP) is a critical barometer for the carbon sequestration capacity of an ecosystem, thereby governing the sustainable development of terrestrial ecosystems. However, altough cities are an integral part of the terrestrial landscape, case-based research specifically examining their NPP and its influencing factors remains notably limited. This research quantifies the spatiotemporal dynamics of the vegetation NPP of Xi'an between 2013 and 2022 useing the Carnegie-Ames-Stanford approach and multisource remote sensing data. Linear trend analysis, random forest regression, and Shapley additive explanations interpretation are integrated to systematically examine the spatiotemporal variations and driving mechanisms of NPP. Results show a 5.48 g C center dot m(-2)center dot yr(-1) annual average increase in NPP over the past decade, with a total accumulation of 83.22 Tg C. The spatial pattern of accumulated NPP exhibits a progressive outward increase from the urban core. NPP increases in urban core areas(1.82 g C center dot m(-2)center dot a(-1)) but decreases in urban expansion areas. Correlation analysis indicates that the proportion of areas whose NPP is driven by multiple climatic factors(31.09 %) substantially exceedes the proportion of areas whose NPP is driven by a single factor (19.13 %). Solar radiation is the dominant climatic driver, and an temperature increases corresponded to NPP declines. The effect of human activities on NPP demonstrates clear threshold effects and nonlinear characteristics. From the urban core to rural areas, the driving mechanism shows the following gradient evolution: landscape configuration-*socioeconomic factors-*human-environment interaction-*natural constraints. The study findings establish a valuable foundation for the management of urban vegetation and ecological planning, thereby informing efforts to harmonize urban expansion with environmental conservation.

Microplastics (MPs) are generally considered biologically inert and do not participate in element cycling in soil because microorganisms in nature lack enzyme systems that can effectively cut off these artificially synthesized polymer chains. However, an increasing number of studies have confirmed that MPs entering the soil can interfere with the stability of the microbial community structure and affect the nutrient cycling processes driven by microorganisms in the soil, thereby affecting greenhouse gas emissions and plant growth. Our understanding concerning the effects of MPs on element cycling, enzyme activity, and microbial gene expression remains unclear. The present review focuses mainly on the effects of MPs on carbon (C), nitrogen (N), and phosphorus (P) cycling on soil and plant responses and introduces related advancements, challenges, limitations, and future directions. MPs can significantly affect soil C, N and P cycles and functional microorganisms in soil and correspondingly alter enzyme activities and gene expression related to greenhouse gas emissions (CH4 and N2O), depending on the interactions between the characteristics of the MPs themselves and the soil environment (e.g., moisture status, redox potential, and the microbial community). Despite the rapid development of life cycle assessment, carbon footprint and sustainable development goals related to MPs, this is still a challenging frontier field, reflected mainly in data gaps and standardization, indistinction of the carrier effect, and incompletion of the impact assessment model. Currently, several controversies remain concerning whether the same MPs have varying effects across different soil types; findings from short-term laboratory experiments often conflict with long-term field data, and MPs ultimately enhance or suppress plant absorption of N and P. This review proposes several valuable suggestions for future research, including long-term field experiments, multifactor interactions, molecular ecology techniques, standardized research methods, and coregulatory effects of viruses and hosts, which will narrow the knowledge gap concerning MPs-mediated element cycles in soil.