Soil microbial response to warming may potentially contribute to the positive priming effect, i.e., accelerating the decomposition of native soil organic carbon (SOC) under the outsourced carbon (C) input. Investigating microbiota that metabolize the outsourced C is essential to deciphering the mechanism of priming effect in response to warming and thus mitigating the SOC loss under warming climate. In this work, we monitored the priming effect at 25 degrees C, 35 degrees C and 45 degrees C over four weeks with weekly addition of 13C-glucose, and subsequently revealed microbial assemblage metabolizing glucose with the DNA stable-isotope probing (DNA-SIP) method. Warming initially inhibited the priming effect, and decreased bacterial alpha-diversity, K/r-strategists ratio (K/r) and recalcitrant C/labile C gene ratio (R/L) in week 1, suggesting that at the onset of the outsourced C input, the increased proportion of r-strategists preferentially utilize the added glucose over SOC to meet their C and energy demands. Yet, in week 4, positive priming effects were intensified by warming with up to 3.8-fold increase at 45 degrees C. Additionally, the primed C was positively correlated with K/r, R/L, and the abundances of chitin degradation genes in week 4. These functions concurred with an increase in the abundance of resource-acquisition strategists such as Streptomyces affiliated to Actinobacteria under warming conditions over time. From week 1 to 4, warming induced a distinctive change in glucose-assimilating bacterial community compositions with a particular decrease in the relative abundance of Actinobacteria while an enriched abundance of Chloroflexi. Taken together, warming-triggered change of priming effect depended on alternation of microbiota and metabolic function over time. These findings provide important insights of how warming mediates microbial metabolic use of fresh C and subsequent SOC mineralization, reflecting the positive feedback between soil C emission and climate warming.

The atmospheric CO₂ growth rate is the observational anchor of the global carbon budget and is often treated as a well-constrained quantity. Here we show that the widely used NOAA marine boundary layer (MBL) growth rate contains a time-varying whole-atmosphere representativeness error linked to network coverage changes. From 1991 to 2024, changes in network coverage and anomalous atmospheric CO₂ growth state explain 73% of the discrepancy between the NOAA MBL estimate and whole-atmosphere growth rates inferred from atmospheric flux inversions. The discrepancy reaches 0.39 ppm yr⁻¹, or 0.83 PgC yr⁻¹, in 2024—a year of record atmospheric growth and the most negative carbon-budget imbalance on record. We compare NOAA MBL against two complementary whole-atmosphere references: data-driven OCO-2/GOSAT satellite growth rates and the median of six in situ atmospheric inversions. The satellite estimate tracks the inversion median, and both depart from NOAA MBL during anomaly years, with an satellite-estimate RMSE of 0.07 ppm yr⁻¹ against inversions, compared with 0.21 ppm yr⁻¹ for NOAA MBL. Part of the apparent carbon-budget imbalance therefore reflects sampling errors in the atmospheric term, and whole-atmosphere growth rates provide a more robust basis for attributing interannual carbon-cycle variability.

Organic cultivation represents an environmentally friendly agricultural practice with the potential to enhance soil microbial diversities and functions. However, the mechanisms by which soil microbial communities regulate microbial metabolic efficiency under organic cultivation remain to be elucidated. Herein, the rice rhizosphere soil samples from three sites in Northeast China were compared for the differences in soil chemical properties, microbial biomass, enzyme activities, and microbial community diversities between organic and conventional rice cultivation at different growth stages. We also analyzed the contributions of these factors to the changes in microbial carbon use efficiency (CUE). Results showed that organic cultivation increased soil pH and available nutrient contents, alleviated microbial carbon and nitrogen limitations, and consequently improved microbial stoichiometric homeostasis and CUE. Conversely, microbial enzyme activities were significantly higher in conventional cultivation than in organic cultivation, especially during the later stages of rice growth. This resource allocation strategy of microorganisms led to a reduction in microbial diversity, biomass, and ultimately, a decrease in microbial CUE. Random forest analysis showed that the content of soil available nitrogen and the threshold element ratio for carbon: nitrogen (TERC:N) were most important predictors of microbial CUE. Additionally, we identified that Geobacteraceae-associated genus, Woesearchaeales-associated genus, Ferruginibacter and Propioniciclava had significant effects on microbial CUE at all three sites. Further, network analysis and partial least squares path model (PLS-PM) revealed that the specific microbial assemblies with high rrn copy number enhance microbial CUE by increasing biosynthesis. This study underscores the potential of organic farming in enhancing soil microbial CUE to mitigate ecosystem carbon losses, providing valuable insights for optimizing land management strategies to achieve soil carbon sequestration and advance sustainable agricultural practices.

Tropical land carbon fluxes dominate the interannual variability (IAV) of atmospheric CO₂ growth, yet the climate controls and underlying mechanisms remain debated. We use a Bayesian data-assimilation framework that integrates multiple satellite-based carbon and water observations to quantify the relative contributions of key climate drivers to tropical land carbon-flux IAV at the grid-cell scale and their dependence on local hydroclimate. Along a gradient from very wet to very dry climates, the contributions of temperature, radiation, and vapor pressure deficit systematically decline, while the contribution of precipitation increases. In dry and very dry regions (<1500mm/yr), precipitation explains more than 40% of the IAV in gross primary production (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE), but only ~0–20% in very wet regions (>2500mm/yr). Conversely, radiation contributes up to ~40% of GPP IAV and ~20% of ER IAV and NEE IAV under very wet conditions. These hydroclimate dependencies also vary seasonally and during climate extremes. We further show that climate contributions are governed primarily by carbon-flux sensitivities rather than by the magnitude of climate anomalies. Our results imply that dominant climate controls on tropical carbon-flux IAV will shift with future climate, underscoring the need to represent climate-dependent sensitivities in carbon-cycle projections.

Low phosphorus availability is a major barrier to soybean cultivation in tropical and subtropical regions, where phosphate is strongly fixed by highly weathered acidic soils. However, little is known about the genetic basis of soybean adaptation to such low-phosphorus environments. Here, we identify the major quantitative trait locus Superior Phosphate Acquisition 10 (SPA10), which confers enhanced phosphate-acquisition efficiency in low-latitude soils. SPA10 encodes a soybean homolog of SENSITIVE TO PROTON RHIZOTOXICITY 1 (GmSTOP1a), a transcription factor central to low-phosphorus and proton-toxicity responses. A naturally occurring 24-bp insertion in the GmSTOP1a promoter, the haplotype prevalent in high-latitude germplasms, has disrupted a GmAGL12 binding site, attenuating the induction of GmSTOP1a expression under low-phosphorus conditions. By contrast, the promoter haplotype that lacks the 24-bp insertion, which predominates in low-latitude soybean, enables strong GmAGL12-dependent activation of GmSTOP1a and downstream genes involved in organic acid secretion, including several multidrug and toxic compound extrusion transporters. This difference in GmSTOP1a regulation determines the capacity of soybean roots to mobilize fixed phosphorus in acidic soils. Functional validation through CRISPR knockout, overexpression lines, promoter swapping, electrophoretic mobility shift assays, and DNA affinity purification sequencing confirmed that GmSTOP1a is a central regulator of low-phosphorus-responsive transcriptional networks and rhizosphere chemical modification. Field trials showed that overexpression of GmSTOP1a significantly increased seed yield in the absence of P fertilizer, demonstrating its agronomic value in P-deficient soils. Population genetic analysis revealed that the superior haplotype of GmSTOP1a underwent targeted artificial selection during the historical expansion of soybean into low-latitude cultivation zones. Our findings reveal a promoter-based regulatory innovation that has enabled soybean to adapt to acidic, low-phosphorus soils, providing a mechanistic foundation for the breeding of P-efficient cultivars for low-latitude cultivation.

The 2023/24 El Niño strongly reduced land carbon uptake, but the persistence of this anomaly after surface cooling remains uncertain. Here we quantify the July 2024-June 2025 global CO2 budget using low-latency fossil emission estimates, three DGVMs, machine learning ocean flux emulators and OCO-2-constrained atmospheric inversions. The atmospheric CO2 growth rate was 2.62 ± 0.08 ppm yr-1, 6.5% above the 2013-2022 July-to-June mean. DGVMs estimate that the net land sink was 1.32 ± 0.19 GtC yr-1 weaker than the 2015-2022 July-to-June mean, whereas combining bottom-up and top-down constraints gives a smaller deficit of 0.49 GtC yr-1. The annual anomaly is dominated by late-2024 land carbon losses. Early-2025 recovery, however, is method-dependent: DGVMs retain a weak annual land-sink deficit, while all inversions indicate fluxes close to the reference mean and a stronger-than-normal northern sink in late spring 2025. Ocean uptake shows no global weakening. A statistical decomposition links global land flux variability mainly to temperature, with terrestrial water storage contributing more strongly at regional scales. These results identify Northern Hemisphere land-sink recovery as a central uncertainty in low-latency carbon-budget assessments.

Context: Soybean monoculture aggravates soil acidification and increases incidence of soybean root rot, thus seriously restricting soybean production. Although soil amendments are widely adopted to mitigate soil-borne diseases and enhance crop yields, the mechanisms for improving soil health remain unelucidated. Objective: This study employed microbial co-occurrence networks and ecological resistance indices to examine how soil amendments reshape microbial diversity, composition, and stability (bacteria, fungi and archaea), and to elucidate the mechanisms through which they alleviate continuous cropping obstacles in soybean. Methods: Based on a three-year field experiment combined with an in vitro co-culture experiment, no soil amendment (CON), lime (LM), lime with straw (LMSS), lime with cow manure (LMCM), crude chitin (CC), and commercial Si-Ca-K-Mg (CSC) amendments were applied to treat severe continuous cropping obstacles in soybean fields. This study evaluated the potential relationships among soil microbial communities, soybean root rot incidence, and soybean yield in response to different soil amendments. Results and conclusions: Soil amendments effectively decreased the soybean root rot incidence and increased soybean yields, with CC showing superior efficacy, achieving a 70 % reduction in disease incidence and over a 30 % increase in yield. Soil amendments noticeably enriched potentially beneficial species with diseasesuppressive and growth-promoting functions, such as Pantoea BASV4, Bacillus BASV6, Humicola FASV38, Tausonia FASV5, and Mortierella FASV6. Co-occurrence network analysis revealed that amendments enhanced microbial network stability and complexity. Notably, CC induced the most resistant microbial communities, whereas LMSS exhibited lower microbial resistance. Structural equation modeling and correlation analysis identified microbial resistance as a critical factor linking disease suppression and yield enhancement. In vitro coculture experiments confirmed that the rhizosphere bacterial suspensions from amended soils inhibited Fusarium oxysporum hyphal elongation, correlating strongly with the abundance of beneficial bacteria. These results demonstrated that targeted amendment application alleviates continuous cropping barriers by recruiting beneficial microbiota and enhancing community resistance. Implications: This study identifies the optimal amendment to ameliorate continuous cropping barriers, offering a theoretical framework and practical guidance for maintaining soil health and promoting crop production.

The conversion of crops to pastures has the potential to mitigate soil organic carbon (SOC) losses associated with long-term intensive cropping. Despite increasing evidence of pasture-induced SOC accumulation, microbial mechanisms governing the spatial sequestration of SOC within aggregate fractions throughout the soil profile of Mollisols under long-term monoculture remain largely unknown. Given the vigorous and deep rooting system of alfalfa, we investigated how the initial conversion of a > 50-year maize monoculture to alfalfa pasture influences SOC sequestration within aggregate fractions across the soil profile and associated microbial communities over the growing season. Alfalfa establishment significantly increased SOC in the mineral-associated aggregate fraction (P < 0.05), with the most pronounced accumulation at 40–50 cm depth (P < 0.01). Correspondingly, alfalfa cultivation markedly shifted microbial community composition. At the flowering stage, copiotrophic taxa such as Subgroup 10 and nitrogen-cycling groups including Nitrospira were enriched across aggregate fractions. At maturity, oligotrophic taxa including Pseudoxanthomonas, Massilia, and Moraxellaceae became more abundant. Notably, alfalfa-driven shifts in microbial community assembly were consistent across aggregate fractions. These findings demonstrate that conversion from maize to alfalfa promotes SOC accumulation in mineral-associated aggregates of deep soil layers. The enrichment of plant species-specific microbial taxa across aggregates suggests enhanced transformation and stabilization of fresh plant-derived carbon inputs.

Climate change poses unprecedented challenges to agricultural sustainability, with profound implications for environmental quality and crop productivity. However, integrated assessments quantifying the specific contributions of climatic drivers versus management practices to agricultural ammonia (NH3) emissions and crop yields remain limited in China, constraining precision air pollution control and threatening national food security. This study employed the DNDC model to simulate fertilizer-related NH3 emissions and crop yields of China's three major crops (rice, maize, and wheat) under current and three representative shared socioeconomic pathways (SSP) representative concentration pathways scenarios (SSP1-1.9, SSP3-7.0, and SSP5-8.5) for 2030, 2050, and 2060, while explicitly partitioning the relative importance of climate change versus nitrogen management variations to agricultural outcomes. Results indicate that fertilizer-related NH3 emissions totaled 3.00 Tg N yr-1 in 2019, with a combined crop yield of 618.76 Tg. By 2060, fertilizer-related NH3 emissions were projected to increase by 2.0%, 12.0%, and 84.3% under SSP1-1.9, SSP3-7.0, and SSP5-8.5, respectively, while crop yields would decrease by 16.7%, 16.1%, and 5.8%. Under SSP1-1.9, the relative importance of climate change for fertilizer-related NH3 emissions (RIe) maintained approximately 50% throughout 2030-2060, suggesting balanced offsetting effects between climate change and the projected nitrogen fertilizer reduction. Conversely, the relative importance of climate change for crop yields (RIy) reached 91% by 2060, demonstrating that crop yield losses were predominantly driven by climatic stresses rather than the fertilizer input adjustment. Under SSP5-8.5, substantial increases in nitrogen fertilization reduced the relative importance of climate change, with RIe and RIy values dropping to 17% and 59% in 2060, respectively. This pattern demonstrates that enhanced fertilization could not fully offset crop yields losses, while 84% of fertilizer-related NH3 emissions increases resulted from intensified fertilizer use. This study provides critical insights for precision emission reduction in agricultural-atmospheric systems and supports China's dual goals of food security and carbon neutrality.

Sustainable intensification of agriculture is dependent on higher fertiliser inputs and balanced nutrient management to increase crop productivity while simultaneously maintaining soil health. Since the long-term use of higher doses of inorganic fertilisers can negatively affect soil ecosystem stability, manure inputs may be a viable alternative that also alters microbial phosphorus (P) metabolism. Using metagenomics and genome binning, we evaluated the shifts in microbial communities and P-cycling genes in a Mollisol after substitution of mineral fertilisers with manure additions. Soil samples were collected at different depths (0-10, 10-20, 20-30, and 30-40 cm) from a field that had undergone 30 years of mineral fertiliser application before transitioning to the following four treatments, each of which was applied for 12 years: no fertilisers (CK), continued mineral fertilisers (CF), CF with 15 Mg ha-1 of cattle manure per year (FM1), and CF with 30 Mg ha-1 of cattle manure per year (FM2). In comparison with CF, CK decreased the concentrations of most P fractions, whereas manure addition had positive effects on P fractions. Different fertilisers yielded distinct P-related microbial communities and networks across various soil depths. At the functional gene level, manure application increased the relative abundance of inorganic P solubilisation genes, particularly in the 0-10 cm and 30-40 cm layers, while reducing the abundance of P-starvation-response genes across all layers. Both mineral fertilisers and manure enhanced the abundance of organic P mineralisation genes in the 10-20 cm and 30-40 cm layers. The abundance of the gcd gene showed a positive relationship with inorganic P solubilisation in the surface layer, whereas those of the ppk1, ppa, and ppx genes were positively correlated with inorganic P solubilisation in the subsoil layers. The construction of metagenome-assembled genomes (MAGs) showed that deeper soil layers offer greater potential for harbouring novel and undescribed microbial lineages and functional genes involved in the P cycle. Overall, supplementation of mineral fertilisers with manure additions significantly affected not only the P fractions but also the P metabolic capacities of the soil microbiome, influencing the soil P cycle in fertilised ecosystems.

The Japan Aerospace Exploration Agency (JAXA) has developed a novel partial column CO2 (XCO2) dataset from Japan’s Greenhouse Gases Observing Satellite (GOSAT) that partitions XCO2 into contributions from the lower troposphere (surface to ~4 km a.g.l.) and upper troposphere (~4 km to ~12 km a.g.l.). Evaluating this two-layer product is essential for its application in studies of atmospheric CO2 distributions and surface fluxes. Here, we assess the JAXA/GOSAT two-layer XCO2 using aircraft measurements from ACT-America, ATom, NOAA aircraft profiling network, and other available datasets, along with global model ensembles from the OCO-2 Model Intercomparison Project (MIP). GOSAT XCO2 generally agrees well with aircraft measurements in zonal means for both tropospheric layers, demonstrating its ability to capture large-scale vertical CO2 structures. A notable low bias of up to 10 ppm is identified in northern high latitudes (50°–80°N). Over northern midlatitudes, particularly North America where aircraft coverage is most extensive, GOSAT shows better agreement with observations in lower-tropospheric XCO2 than the OCO-2 MIP simulations, suggesting potential biases in model surface fluxes and/or transport. Significant differences between GOSAT and OCO-2 MIP are found in both layers over the Amazon (2–10 ppm), southern China (0–8 ppm), India (5–8 ppm), tropical Africa (2–10 ppm), and the Arctic (>10 ppm). However, limited aircraft data in these regions constrain independent validation. Our findings demonstrate that the GOSAT two-layer XCO2 provides a valuable constraint for identifying possible biases in CO2 fluxes and vertical mixing in current global models and has potential to improve surface CO2 flux inversions.

Robust information on the spatial distribution of global carbon fluxes is required to project the future trajectory of carbon-climate feedback effects and atmospheric CO2 concentrations. Estimates of the latitudinal partitioning of carbon fluxes from top-down atmospheric CO2 inverse models currently diverge widely, because of methodological limitations or systematic biases in models or observations. We use airborne CO2 observations from the NASA Atmospheric Tomography Mission to evaluate and refine inverse model estimates from the Orbiting Carbon Observatory version 10 Model Intercomparison Project of total CO2 exchange for the two-year period of June 2016-May 2018. Applying emergent concentration-flux relationships as constraints reduces zonal total flux uncertainties by 46 to 56% relative to the full v10 MIP ensemble and by 17 to 28% relative to the subset excluding satellite observations over ocean. Subtracting independent estimates of fossil-fuel emissions and air-sea gas exchange results in residual land fluxes with a large northern extratropical sink, a small southern extratropical sink, and a small tropical source. The airborne-derived tropical land source disagrees with a large tropical land sink from process-based terrestrial models combined with estimates of land use emissions and river fluxes, representing an important challenge for our understanding of the global carbon cycle. The large implied northern extratropical sink can be explained either by underestimated land uptake by process models or a combination of process model bias and overestimated fossil fuel emissions.

Abstract Amplified warming has altered the phenology and structure of high‐latitude forests, yet their carbon uptake responses to environmental variations remain uncertain. Using satellite observations of solar‐induced chlorophyll fluorescence (SIF), we quantify interannual variations in growing‐season (GS) productivity of these forests and their climatic drivers. GS productivity is largely controlled by early‐ and peak‐season temperatures: warmer springs enhance carbon uptake and, despite moderate legacy declines later in the season, overall productivity increases in warmer years in most regions. Pronounced heterogeneity is observed among plant functional types—deciduous needleleaf forests (DNF) show weaker temperature sensitivity and stronger water dependence than other forests. In DNF, temperature effects weaken or reverse under dry conditions and persist after accounting for canopy structural effects, indicating strong water constraints on physiological responses. These results underscore the heterogeneous climate sensitivities of high‐latitude forests and highlight SIF as a powerful tool for monitoring their productivity and responses to climate.

Soil acidification from long-term synthetic fertilizer use threatens agricultural sustainability. This study investigated the potential mechanisms by which long-term cattle manure application mitigates fertilizer-induced acidification in a high-organic-matter Mollisol. Soils were sampled from a decade-long field experiment with four treatments: no fertilizer (NoF), synthetic fertilizer alone (CF), and CF supplemented with 15 (CFM) or 30 Mg ha−1 (CFM2) of cattle manure. Samples collected in 2021 and 2022 from 0 to 40 cm depth were analyzed for soil pH, pH buffering capacity (pHBC), exchangeable H+ and Al3+, cation exchange capacity (CEC), exchangeable base cations, and responses to simulated acidification. Continuous synthetic fertilization decreased soil pH and pHBC, increased exchangeable Al3+, and depleted exchangeable base cations in the 0–20 cm plow layer. In the 0–10 cm layer, CFM2 raised soil pH to near-neutral conditions, 1.91 pH units higher than CF in 2022. Exchangeable Al3+ decreased from approximately 0.19 cmol kg−1 under CF to 0.09 and 0.04 cmol kg−1 under CFM and CFM2, respectively. NoF did not restore soil pH to its initial level. Cattle manure co-application increased soil pH, pHBC, CEC, and exchangeable K+, Ca2+, and Mg2+ in a dose-dependent manner. Under simulated acidification, soil resistance followed CFM2 > CFM > NoF > CF. The initial exchangeable base-cation pool under CFM2 was approximately 20% greater than CF, thereby providing a larger proton-neutralizing reservoir. These benefits were primarily confined to the 0–20 cm plow layer. Overall, cattle manure effectively mitigated synthetic fertilizer-induced acidification by rebuilding exchangeable base-cation pools and enhancing soil buffering capacity.

Different fertilization regimes strongly influence carbon cycling processes; however, the functional responses of microbial communities driving these processes remain poorly characterized. Here, metagenomic sequencing combined with binning approaches was applied to investigate the shifts in microbial composition and function related to soil carbon cycling in a 40-year fertilization experiment with six regimes in black soil. Fertilization altered the microbial assembly process, with chemical fertilization (CF) leading to a shift in community assembly toward deterministic processes through intensified heterogeneous selection compared to unfertilized control (NoF). Chemical fertilization plus straw application (CFS) significantly increased the abundance of genes related to recalcitrant carbon degradation (celF, chi, pel, and GE). Manure fertilization (M) increased the abundance of hcA associated with carbon fixation. While straw application (S) demonstrated no substantial impact on the functional gene profiles. The taxon-function co-occurrence network reveals that distinct key taxa exhibit convergent functional roles in carbon decomposition and transformation, whereas treatment-specialized taxa emerge as functional specialists, contrasting with these generalists. Both the carbon-cycling taxonomic groups and functional genes were governed by a shared suite of environmental factors (pH, Microbial biomass carbon, and Microbial biomass nitrogen), suggesting a consistent response of carbon-cycling functional genes and microbial taxa to environmental change. In addition, six metagenome-assembled genomes (MAGs) were found to harbor conserved carbon fixation genes (accA, icd, maeB), indicating their potential as biomarkers of soil carbon sequestration capacity. This study elucidates how long-term fertilization reshapes microbial carbon-cycling process, providing a genomic framework to guide sustainable soil management.

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesise datasets and methodologies to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (E-FOS) are based on energy and cement production data. Emissions from land-use change (E-LUC) are estimated by bookkeeping models based on land-use data. The global atmospheric CO2 growth rate (G(ATM)) is computed from changes in concentration measured at surface stations. The global net uptake of CO2 by the ocean (S-OCEAN) is estimated with global ocean biogeochemistry models and observation-based fCO(2)-products. The global net uptake of CO2 by the land (S-LAND) is estimated with dynamic global vegetation models. Additional lines of evidence are provided by atmospheric inversions, atmospheric oxygen measurements, ocean interior observation-based estimates, and Earth System Models. This year, we introduced corrections on the E-LUC, S-OCEAN and S-LAND estimates. The sum of all sources and sinks results in the carbon budget imbalance (B-IM), a measure of imperfect data and incomplete understanding of the contemporary carbon cycle. All uncertainties are reported as +/- 1 sigma. For the year 2024, E-FOS increased by 1.1 % relative to 2023, with fossil emissions at 10.3 +/- 0.5 GtC yr(-1) (including the cement carbonation sink, 0.2 GtC yr(-1)), E-LUC was 1.3 +/- 0.7 GtC yr(-1), for total anthropogenic CO2 emissions of 11.6 +/- 0.9 GtC yr(-1) (42.4 +/- 3.2 GtCO(2) yr(-1)). Also, for 2024, G(ATM) was 7.9 +/- 0.2 GtC yr(-1) (3.73 +/- 0.1 ppm yr(-1)), 2.2 GtC above the 2023 growth rate. S-OCEAN was 3.4 +/- 0.4 GtC yr(-1) and S-LAND was 1.9 +/- 1.1 GtC yr(-1), leaving a large negative B-IM (-1.7 GtC yr(-1)), suggesting that the total sink or G(ATM) is strongly overestimated in 2024. The global atmospheric CO2 concentration averaged over 2024 reached 422.8 +/- 0.1 ppm. Preliminary data for 2025 suggest an increase in E-FOS relative to 2024 of +1.0 % (0.2 % to 1.7 %) globally, and atmospheric CO2 concentration increasing by 2.1 ppm reaching 425.6 ppm, 53 % above the pre-industrial level (around 278 ppm in 1750). Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959-2024, with a near-zero overall budget imbalance, although discrepancies of up to around 1 GtC yr(-1) persist for the representation of annual to decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows: (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the mean ocean sink.

In 2024,the atmospheric CO2 growth rate based on the globally averaged ma-rine boundary layer(MBL)observa-tions from the National Oceanic and Atmospheric Administration(NOAA)network reached 3.73±0.08 ppm yr-1,marking a record high since contin-uous measurements began in 1959(Fig.1a)[1].The whole-atmosphere growth rate derived from independent OCO-2 satellite observations for 2024 was 3.20±0.1 ppm yr-1 using the Growth Rates from Satellite Observa-tions data-driven approach(GRESO)from Ref.[2],the highest value of the OCO-2 record since 2015.The whole-atmosphere growth rate derived from our flux inversion models assimilating OCO-2 observations mainly over land for 2024 was 3.23±0.12 ppm yr-1,thus unsurprisingly being almost equal to GRESO and less than the MBL sta-tions but still a record high in the OCO-2 inversions record since 2015.

Abstract The Amazon rainforest is a critical regulator of the global carbon cycle, yet its resilience to compound climate extremes remains uncertain. The severe drought–heat event of 2023, marked by record temperatures and hydrological stress, offers an opportunity to examine the vulnerability of Amazon carbon sink under extreme conditions. In this issue, Botía et al. (2026, https://doi.org/10.1029/2025AV001658) presents a comprehensive, multi‐constraint assessment of the impact of 2023 drought‐heat extremes on the Amazon carbon cycle. Their synthesis suggests that the Amazon acted as a weak net carbon source in 2023, primarily due to suppressed plant growth during the drought‐affected second half of the year. The study also reveals discrepancies between local flux measurements, basin‐scale inversions, and dynamical global vegetation model (DGVM) simulations, highlighting persistent challenges related to scale dependence, model structure, and representation of drought processes in DGVMs. Together, these findings underscore both the growing vulnerability of the Amazon carbon sink and the urgent need for sustained, integrated observing and modeling systems to constrain its response to future climate extremes.

Microbial community structure plays a critical role in regulating soil organic carbon (SOC) mineralization in agricultural systems. However, the interrelationships between microbial life-history strategies and SOC mineralization under different tillage practices in erosion-prone landscapes remain insufficiently understood. This study explored the microbial mechanisms underlying SOC mineralization across three tillage systems, conventional tillage with straw removal (CT), conventional tillage with straw incorporation (CTS), and no-tillage with straw mulch (NTS), on a hillslope in Northeast China's black soil region. Cumulative SOC mineralization (1132.8-3044.5 kg C ha(-1)) varied significantly with slope positions and tillage practice (p < 0.05), with upper and lower positions exhibiting 50.2 % and 34.5 % higher values than the middle position, respectively. Compared to CT, CTS increased SOC mineralization by 68.5 %. Although NTS also exhibited higher mineralization than CT, it promoted SOC storage as confirmed by positive C balance. Microbial life-history strategies emerged as stronger predictors of SOC mineralization than microbial diversity alone. Bacterial communities displayed distinct shifts in response to erosion and deposition, transitioning from r-strategists in nutrient-rich upper and lower positions to K-strategists in the nutrient-depleted middle area. In contrast, fungal communities responded primarily to tillage practice, with the abundant input of fresh straw favoring r-strategist fungi (e. g., Ascomycota) as key drivers of SOC mineralization and accumulation, rather than K-strategists. Our findings provide mechanistic insights into microbe-mediated C cycling in agricultural systems and support the implementation of conservation tillage practices to enhance SOC sequestration in erosion-vulnerable landscapes.

The synergistic mechanisms by which potassium high-efficiency (KHE) vegetable soybeans coordinate root exudation and microbial recruitment to enhance potasium absorption under low-K stress remain unclear. Integrating hydroponic and pot experiments, this study analyzed root organic acid exudation, soil potassium availability, microbiome structure, and isolated K-solubilizing bacteria using KHE and K low-efficiency (KLE) varieties. Results showed that under low-K stress, KHE plants exhibited a resilient exudation profile, notably surging malonic acid secretion. This trait mechanistically explains the effective soil K activation in pot experiments, indicated by significant rhizosphere acidification positively correlating with total K depletion. Concurrently, the KHE variety maintained a stable rhizosphere microbiome, characterized by the selective enrichment of specific bacterial (Paenibacillus, Rhodanobacter) and fungal (Penicillium, Aspergillus, Chaetomium) genera. To validate this, we isolated Paenibacillus strains BK1 and BK2 from the KHE rhizosphere. BK2 demonstrated potash feldspar activation (5.7