Excessive fertilizer application leads to substantial nutrient loss, low efficiency, and severe environmental issues. Therefore, improving nutrient management is critical for sustaining crop productivity while also reducing environmental burdens. In this study, a field experiment was conducted in the Erhai Lake Basin from 2023 to 2024 to evaluate the effects of four fertilization treatments, namely no fertilization (CK), farmers' practices (FP), optimized fertilization (OPT), and balanced fertilization (BF, fertilization adjusted based on crop nutrient requirements and soil nutrient supply), on crop productivity and nitrogen use efficiency (NUE) in a grain-vegetable rotation system. OPT and BF significantly improved lettuce and corn yields, N uptake, and NUE compared with FP. OPT increased N uptake by 5.50-31.7% compared with FP, whereas BF achieved the highest NUE. OPT reduced inorganic N leaching and runoff by 31.5% and 35.0%, respectively, compared with FP, whereas BF achieved greater reductions of 63.3% and 66.8%, respectively. FP resulted in the highest reactive nitrogen losses and associated environmental impacts. OPT generated the highest production profit, with a net ecosystem economic benefit of 49,552 US$ ha-1 yr-1 , whereas BF showed the highest system coordination degree, indicating the best overall performance across productivity, economic return, and environmental sustainability. These results demonstrate that optimized nutrient management, particularly BF, can maintain crop productivity while markedly reducing environmental N losses, thereby providing strong support for sustainable subtropical grain-vegetable production.

Soil organic carbon (SOC) sequestration is vital for food security and climate mitigation. However, its long-term response to fertilisation remains unclear. Using the 180-year Broadbalk Experiment (the world's longest-running fertilisation trial; Rothamsted, UK), combined with 14C labelling and metagenomics, we identified fundamentally distinct mechanisms of SOC accumulation: a microbially mediated dual pathway under organic fertilisation versus a resource-limited pathway under inorganic fertilisation. Sustained organic inputs matched inorganic fertilisers in maintaining crop yields while increasing total SOC by 160% (relative to a no-fertilisation control), far exceeding the 26% gain under inorganic fertilisation. Mechanistically, the continuous supply of labile organic matter provided an energetic surplus, allowing copiotrophic microbial communities with high carbon use efficiency to reduce investment in energy-intensive enzyme synthesis. This metabolic efficiency facilitated a dual-pathway expansion, elevating dynamic particulate organic carbon (POC) from 1.4 to 7.5 g kg-1, while microbial assimilation and necromass accumulation concurrently increased mineral-associated organic carbon (MAOC) from 6.8 to 21.5 g kg-1. Conversely, inorganic fertilisation induced an oligotrophic 'mining' strategy, in which microorganisms upregulated the degradation of complex organic matter under carbon-limited conditions, restricting sustained SOC accumulation primarily to the MAOC pool. A global meta-analysis of field experiments (0-120 years) corroborated these temporal trajectories across diverse soil types, showing that SOC under organic fertilisation increases in a time-dependent manner, reaching a 77% gain after 80 years (three-fold greater than under inorganic inputs). Overall, organic fertilisation enhances total SOC via POC and MAOC accumulation, whereas inorganic fertilisation mainly increases MAOC. Long-term SOC persistence depends not only on carbon inputs, but also on microbial community traits and necromass dynamics, suggesting that aligning nutrient inputs with these biological mechanisms is critical for sustainable carbon sequestration.

Sustainable maize production necessitates scientific application of enhanced-efficiency fertilizers, with a rational blending ratio of controlled-release urea (CRU) to conventional urea being an indispensable strategy, yet the trade-offs across agronomic, environmental, and economic perspectives remain inadequately quantified. To address this challenge, a four-year field experiment was conducted to evaluate the comprehensive impacts of five blending ratios (0%, 30%, 50%, 70%, and 100% of CRU at 225 kg N ha−1, CR0%–CR100%) in film-mulched maize production. This study employed data-mining to establish region-specific emission factors, life cycle assessment (LCA) for environmental impacts, and the analytic hierarchy process (AHP) for multi-objective optimization decision. The findings indicated that the CR70% treatment (70% CRU of total) attained a synergistic “win-win-win” equilibrium. From an agronomic perspective, the CR70% maximized grain yield (16.6 Mg ha−1) exhibited superior performance in comparison to both sole urea (CR0%; +16.1%) and full CRU (CR100%; +5.1%). From an environmental perspective, CR70% substantially reduced total reactive N losses, decreased soil acidification and water eutrophication potentials by 26.9% and 26.8% respectively, and lowered the carbon footprint compared to CR0%. From an ecological perspective, CR70% exhibited the highest net ecosystem carbon benefits (NECB; 37.2 Mg C ha−1), net ecosystem economic benefits (NEEB; 5513 USD ha−1) and emergy sustainability index (1.98), surpassing both CR0% and CR100%. The AHP integrated criteria including yield, carbon and nitrogen footprints, NEEB, NECB, and ESI confirmed CR70% as the optimal strategy in this region. A rational blending ratio of CRU and conventional urea resolves key performance trade-offs, offering a robust, evidence-based strategy for achieving sustainable maize production.

The influence of excessive phosphorus (P) fertilization on microbially associated organic P mineralization in the rhizosphere of intensively managed vegetable crops remains poorly understood. To clarify the responses of the alkaline phosphatase (ALP) phoD-harboring bacterial communities to P transformation in vegetable systems, a field experiment with pepper was conducted in southwestern China under three P application levels (CK, low P (LP), and high P (HP)). Bulk and rhizosphere soils were sampled across three key pepper growth stages for systematic analysis. Our results demonstrated that ALP activity was 16.7% higher in the rhizosphere than in bulk soil. Under HP treatment, ALP activity significantly increased by 31.7% and 28.2% compared with the CK and LP treatments, respectively. Random forest and correlation analyses revealed that increasing P input shifted keystone phoD-harboring bacteria from the oligotrophic genus Lysobacter to the copiotrophic genus Bradyrhizobium. Compared to CK and LP treatments, the relative abundance of specialists decreased by 15.0% and 9.0% under HP, whereas that of opportunists increased by 13.0% and 6.0%, respectively. Notably, the abundance of opportunists exhibited a positive correlation with both available P (AP) and ALP activity, while specialists showed negative correlations. The decline in specialists abundance was further associated with a simplified co-occrrrence, characterized by decreased modularity, increased average path length and a reduction in the number of keystone taxa. Collectively, these findings illuminate how excessive P input alters the interrelationships among AP, ALP activity, and the phoD-harboring bacterial community, ultimately driving a shift from specialist- to opportunist-dominated ecotypes in the pepper rhizosphere.

Climate change poses significant challenges to urban trees, which exhibit unique physiological responses to urban environments and are often transplanted outside their native ranges. These factors make it essential to refine methods for understanding how urban tree population structure and functioning may shift under future climate conditions. This study presents an integrated framework combining field surveys, climate-niche safety margins, and physiological trait assessments to evaluate the climate resilience of urban woody plants in subtropical regions. Focusing on Chongqing, China, we compiled a comprehensive inventory of 333 urban woody species based on field data and existing records. Analysis of climate-niche safety margins revealed distinct vulnerability patterns across life forms, with all 293 analyzed species projected to exceed their maximum temperature tolerance thresholds under the Shared Socioeconomic Pathway 3-7.0 scenario by 2050. Trees consistently exhibited greater projected temperature sensitivity compared to shrubs, with deciduous trees being the most vulnerable-55 % of species exceeded their mean annual temperature safety margins. Physiological heat tolerance was assessed for 21 woody plant species during a 13-day extreme heat event, revealing substantial interspecific variation. Generalized additive models demonstrated that the 95th percentile of maximum temperature of the warmest month and the 5th percentile of annual precipitation collectively explained 70.96 % of the observed variation in heat tolerance through non-linear relationships. Cross-validation (mean R2 = 0.347) indicated moderate predictive accuracy, while underscoring the limitations of inferring physiological mechanisms solely from climatic correlations. These findings validate the relevance of climate realized niches in predicting heat tolerance and highlight the complexity of species-climate interactions. The proposed framework offers a systematic approach to climate-resilient urban forest management, providing practical guidelines for species selection and risk assessment in subtropical urban environments.

The influence of excessive phosphorus (P) fertilization on microbially associated organic P mineralization in the rhizosphere of intensively managed vegetable crops remains poorly understood. To clarify the responses of the alkaline phosphatase (ALP) phoD-harboring bacterial communities to P transformation in vegetable systems, a field experiment with pepper was conducted in southwestern China under three P application levels (CK, low P (LP), and high P (HP)). Bulk and rhizosphere soils were sampled across three key pepper growth stages for systematic analysis. Our results demonstrated that ALP activity was 16.7% higher in the rhizosphere than in bulk soil. Under HP treatment, ALP activity significantly increased by 31.7% and 28.2% compared with the CK and LP treatments, respectively. Random forest and correlation analyses revealed that increasing P input shifted keystone phoD-harboring bacteria from the oligotrophic genus Lysobacter to the copiotrophic genus Bradyrhizobium. Compared to CK and LP treatments, the relative abundance of specialists decreased by 15.0% and 9.0% under HP, whereas that of opportunists increased by 13.0% and 6.0%, respectively. Notably, the abundance of opportunists exhibited a positive correlation with both available P (AP) and ALP activity, while specialists showed negative correlations. The decline in specialists abundance was further associated with a simplified co-occurrence, characterized by decreased modularity, increased average path length and a reduction in the number of keystone taxa. Collectively, these findings illuminate how excessive P input alters the interrelationships among AP, ALP activity, and the phoD-harboring bacterial community, ultimately driving a shift from specialist-to opportunist-dominated ecotypes in the pepper rhizosphere.

Vegetable production systems are important sources of agricultural ammonia (NH3) emissions. However, the characteristics of NH3 emissions from global vegetable systems and effective mitigation measures remain poorly understood. This study conducted a meta-analysis to elucidate global NH3 emission patterns, drivers, and mitigation options in vegetable production. Additionally, we proposed sustainable integrated nitrogen (N) fertilizer management strategies and evaluated their effectiveness through two field trials. The meta-analysis showed that the global NH3 emission factors for open-field and greenhouse vegetable systems were 6.1% and 2.8%, respectively. The estimated global synthetic N fertilizer-induced NH3 emissions from vegetable systems were 1087 Gg N year−1, which was 46% lower than the estimate based on the Intergovernmental Panel on Climate Change default value. N fertilizer type, application rate, placement method, and soil mineral N concentration were identified as the primary predictors of N fertilizer-induced NH3 emissions. Furthermore, our meta-analysis demonstrated that knowledge-based 4 R nutrient stewardship practices effectively reduced NH3 emissions, particularly through optimized N application rates (−39%), use of slow/controlled release fertilizer (−52%), and subsurface application methods (−69%). Our field trials further demonstrated that integrated N management measures enhanced NH3 mitigation while increasing vegetable yield. This study provides quantitative evidence for developing effective NH3 mitigation strategies and advancing sustainable N management in global vegetable production systems.

Intensive pesticide use can enhance crop yields while posing risks to non-target organisms across ecological compartments. A watershed-scale, process-based framework that dynamically links crop-specific applications of multiple pesticides (including transformation products) with their fate in soil and water is still lacking. This study introduces the MARINA-Pesticides model, that simulates monthly, sub-basin-scale transport of 30 pesticides and three transformation products from 12 crops to river networks, while accounting for their degradation, partitioning, and transport processes in both croplands and rivers. We apply the MARINA-Pesticides model to the Three Gorges Reservoir Area (TGRA) to quantify pesticide residue concentrations in soil and river and to assess associated ecological risks. In 2020, an estimated 903 tonnes of pesticides were applied to croplands across the TGRA, with 3% exported to aquatic systems, 10% remaining in soils and 87% degraded. Among 30 pesticides, chlorpyrifos, imidacloprid, and carbendazim posed ecological risks in the soil. In total, 11.2 tonnes of parent pesticides and 2 tonnes of three transformation products were exported into rivers, predominantly via surface runoff (91%), with the remainder via soil erosion (9%). Riverine pesticide concentrations peaked during the summer season. In summer, chlorpyrifos, imidacloprid, and fenpropathrin posed a high risk to riverine ecosystems. Our conclusions advance the understanding of the multi-pesticide fate and timing in diverse agricultural watersheds, supporting guidance for soil and water-resource protection.

CONTEXT: As healthier diets drive global vegetable production, synergistic optimizing water-fertilizer management has become pivotal to balance its production with environmental sustainability. However, a comprehensive analysis of the food-energy-water-carbon (FEWC) nexus associated with these practices remained limited. OBJECTIVE: We aimed to develop a novel integrated soil-water-fertilizer synergy (ISWFS) framework tailored Southern China for vegetable production. We also sought to establish a comprehensive FEWC nexus assessment system to quantitatively evaluate its sustainability performance. This work addresses the existing research gap in systematic FEWC nexus analysis for open-field vegetable drip fertigation systems. METHODS: This study proposed ISWFS framework which innovatively combines integrated soil-crop system management with water and fertilizer synergetic strategies using drip fertigation techniques, and compared it with conventional management (FP + TI: farmers' fertilization practice with traditional irrigation) and other optimized practices (OPT+TI: optimized fertilization with traditional irrigation; OPT+DI: optimized fertilization with drip irrigation). A two-year field experiment and life cycle assessment (LCA) were used to evaluate their outcomes across the FEWC nexus. RESULTS AND CONCLUSION: Our results found that OPT+TI reduced fertilizer inputs by 44.1-48.1% and environmental impacts by 33.7-54.5% without yield loss compared to FP + TI. OPT+DI practice further improved water use efficiency (WUE) 31.0% and partial factor productivity of nitrogen fertilizer (PFPN) 41.5%, leading to greater pepper yield compared to OPT+TI. Notably, ISWFS delivered the most synergy benefits, increasing yield, WUE and PFPN by 18.1%, 39.1% and 47.0% over OPT+TI, respectively. It simultaneously reduced net greenhouse gas (GHG) emissions by 51.5%, reactive nitrogen losses by 72.3%, water footprint by 61.7%, and energy input by 42.1%, leading to the highest integrated FEWC nexus index of 0.87. This study confirms that ISWFS is a scalable sustainable intensification model that holistically addresses the FEWC nexus by reconciling climate mitigation with farm profitability. SIGNIFICANCE: These findings provide a context-specific, intelligent and systematic decision-support framework for open-field vegetable systems. The established FEWC nexus assessment system offers a new methodological reference for global sustainable vegetable production.

Reducing anthropogenic nitrous oxide emissions from agricultural lands is critical to combating climate change. Nitrification inhibitors and synthetic microbial consortia have already demonstrated potential in decreasing soil nitrification-derived nitrous oxide emissions. However, targeted interventions addressing denitrification sources while balancing agricultural sustainability remain challenging. Here, we identify triazole compounds as cytochrome P450 inhibitors capable of reducing soil denitrification-derived nitrous oxide emissions by 85-100% in laboratory settings. Extending our findings to in-situ paddy fields, we observe that triazoles (at 0.05% of fertilizer nitrogen) reduce nitrous oxide emissions by 33-54%. These potential inhibitors specifically target the NAD(P)H and nitric oxide binding sites of P450Nor, strongly inhibiting fungal nitrous oxide emissions. Occupancy of the heme-iron(III) site within the P450Nor active pocket enhances this selectivity, which is critical for effective inhibition. Given the projected increase in agricultural nitrous oxide emissions, our findings offer insights into the development of denitrification inhibitors and highlight triazole as a promising solution for nitrous oxide mitigation in agricultural ecosystems. A key gap in agricultural climate mitigation is the lack of interventions that specifically target denitrification. This study identifies that triazole compounds act as cytochrome P450 inhibitors, effectively reducing N₂O emissions from denitrification.

Recycling organic phosphorus (P) sources may reduce dependence on synthetic P fertilizers in sustainable agriculture. However, the overall lack of understanding of the impact of organic P management practices on crop yields and the environment limits further optimization of organic P strategies. Herein, we first executed a global meta-analysis of over 860 paired observations to validate potential indicators for delineating risk zones for organic P fertilizer management. Then, a combination of machine learning tools and global datasets was used to further identify the risk zones for organic P management practices. Finally, an optimal organic P management strategy was developed considering the total P inputs, types of organic P sources, organic P proportions, and organic P management risk zones. Results indicated that the P activation coefficient (PAC) can be used as a potential indicator for delineating risk zones for organic P management. Hypothesis-oriented path analysis suggests that P inputs under low-soil-PAC conditions drive the preferential allocation of P to the occluded and moderately labile P pools and that organic P fertilizer application can positively affect labile P. P inputs under high-soil-PAC conditions have a more balanced effect on various P fractions of soil, and P inputs through organic fertilizers are primarily stored in the organic P pool. Current organic P management practices do not benefit food production in case of low-soil-PAC cropland and may increase the risk of P runoff in case of high-soil-PAC cropland. A combination of optimal organic P management with risk zones achieved a 13.3 % reduction in global P runoff and a 10.7 % increment in global food production compared with the use of synthetic P fertilizers alone. Our study provides a solution for enhancing the efficient use of organic P resources to create more productive, clean, and sustainable food production systems.

Context: Potassium (K) is essential for crop productivity, yet China's heavy reliance on imported potash threatens national food security. While crop residue return is a key strategy for recycling K, residue-derived K inputs remain poorly quantified. Existing estimates are highly uncertain because they rely on static average parameters (harvest index and K concentrations), neglect regional and yield-related variability, and lack quantitative data on crop residue return rates. Objective: This study developed a regionalized, yield-dependent statistical modelling framework to accurately quantify crop residue production and K accumulation, and evaluated K recycling and soil K balance across China's major maize, wheat, and rice systems. Methods: Here, 20,756 observations from the literature and field trials were synthesized to derive regionalized parameters for grain and residue K concentrations and to develop harvest index-based regionalized linear mixedeffects models for predicting residue yields of the three major cereal crops. Additionally, a nationwide survey of 5805 farmers was conducted to quantify crop- and region-specific residue return rates. Results: The harvest index of maize and rice has increased markedly over recent decades. A critical physiological finding was the occurrence of luxury K uptake, whereby crops absorb K in excess of target yield-related requirements, often leading to greater K accumulation in crop residues rather than in the grains. By 2020, total residue production reached 620 Mt, while residue K accumulation amounted to 10.7 Mt, which is 35.4% above previous estimates. Driven by the confluence of yield-induced luxury uptake and expanded residue retention, residue K return nearly doubled from 5.49 Mt in 2010-9.25 Mt in 2020. This influx clearly outpaced the growth in mineral K fertilizer input (2.89-4.53 Mt), effectively pivoting China's cereal crop soil K balance from a -2.23 Mt deficit to a 1.2 Mt surplus. Additionally, residue return provided a significant carbon sequestration benefit of 46.7 Mt C annually. Conclusions: K supply from residue return in China's major cereal systems has been substantially underestimated. Large amounts of K stored in cereal crop residues are increasingly recycled to croplands through residue return. The switch from a soil K deficit to a modest national K surplus indicates requires re-evaluating and optimizing current K fertilizer recommendation schemes, including reducing K input from fertilizer and manure in cropping regions with a large K surplus.

Optimizing nitrogen (N) management is key to high-yield, high-quality, and environmentally sustainable vegetable production. However, the long-term sustainability of integrated N management strategies considering agronomic performance, environmental impacts, and economic outcomes remains insufficiently evaluated, particularly in subtropical vegetable systems. This study combined two consecutive four-year field experiments with a multi-objective sustainability assessment framework integrating life cycle assessment (LCA) to systematically evaluate representative N management strategies in subtropical open-field pepper production. Experiment 1 assessed five N application rates, and Experiment 2, using the optimized rate, evaluated four N sources: conventional urea (CU), organic–inorganic fertilizer (OIF), stabilized fertilizer with nitrification inhibitor (NI), and controlled-release urea (CRU). In Experiment 1, the conventional N practice (FNP) with the highest N rate was the least sustainable, characterized by low N use efficiency, high environmental burdens, high social costs (including ecosystem and human health damages), and poor fruit quality. In contrast, the optimized N strategy (OPT) reduced N input while maintaining yields, improving N use efficiency and fruit quality, and decreasing environmental burdens by 43–59% and social costs by 46%. Experiment 2 further demonstrated that, compared with CU, the OIF, NI, and CRU further enhanced sustainability. Notably, NI and CRU enhanced pepper yield by 9–11%, N use efficiency by 9–17%, and improved fruit quality traits. These treatments also reduced environmental burdens by 14–52% and social costs by 31–40%, and increased net ecosystem economic benefits by 8–16%. Overall, integrating optimized N application rates with enhanced-efficiency fertilizers offers a promising strategy to achieve high yield, better quality, lower environmental burdens, and greater economic benefits in subtropical vegetable production. This study provides long-term field evidence and a comprehensive assessment framework for identifying sustainable N management strategies and supporting region-specific fertilizer management decisions.

Irrigation using micro-nano bubbles water (MNBW), an innovative micro-nano technology, has been increasingly used in agriculture. Nonetheless, a comprehensive analysis quantifying the effects of MNBW on crop yield across diverse soil conditions, agronomic practices, and crop varieties is still lacking. We conducted a global meta-analysis of 2,398 data pairs from 35 peer-reviewed articles to quantify the effects of MNBW on crop yield, quality, water use efficiency (WUE), plant growth and development, and soil physicochemical and microbial properties under different soil conditions and agronomic management practices. MNBW significantly increased crop yield, Vitamin C (Vc) content, and WUE by 13.55

Nitrogen (N) fertilization influences soil organic carbon (SOC) formation by regulating plant inputs and microbial activity; however, the relative contributions of plant- versus microbial-derived carbon (C) to SOC accumulation remain unclear, largely due to site-specific variations in soil properties and the complex transformation pathways governing C stabilization. Here, we used amino sugars and lignin phenols as molecular tracers to quantify microbial necromass- and lignin-derived C contributions to SOC under N fertilization across four long-term maize field experiments in Quzhou and Changwu (alkaline, low-fertility soils) and Lishu and Yaan (acidic, high-fertility soils). Although N fertilization increased SOC across all sites, the dominant pathways for C accumulation differed in contrasting soils. In alkaline, low-fertility soils, SOC accumulation was primarily associated with greater lignin-derived C, regulated by soil geochemical properties and aggregate protection rather than increased plant inputs. In acidic, high-fertility soils, microbial necromass contributed more to SOC accumulation and was associated with greater lignin oxidation, reduced oxidase activity, and elevated oxalate-extractable Fe/Al oxides. These divergent mechanisms explain variability in SOC responses to N fertilization and emphasize the need for soil-specific nutrient management strategies to maximize C retention in croplands.

The rhizosphere microbiome plays a crucial role in determining plant performance and fitness. Nevertheless, regulatory mechanisms linking host genetic variation, root gene regulation and microbiome assembly-and their collective influence on plant nutritional traits-remain poorly understood. Here we generated and integrated 1,341 paired datasets, including root transcriptomes, rhizosphere bacterial 16S rRNA profiles and root ionomes, across 175 resequenced Brassica napus ecotypes grown at two contrasting field sites. We identified 203 highly heritable bacterial amplicon sequence variants (ASVs), many of which were significantly associated with root nitrogen (N) levels. Host transcriptome-wide gene expression and these microbial features together explained up to 45% of natural variation in N uptake while genome-wide association analyses revealed host loci regulating ASV abundance, many of which were under the control of eQTL hotspots linked to carbon and N metabolism. Isolate-level inoculation, whole-genome sequencing, metabolite profiling and confocal imaging demonstrated that the dominant, genetically regulated bacterial genus Sphingopyxis modulates auxin biosynthesis and promotes lateral root development to enhance N acquisition under stress. This study therefore identifies Sphingopyxis as a functionally relevant taxon with potential for microbiome-assisted breeding of nutrient-efficient crops.

Phosphorus (P) deficiency is a major constraint on crop productivity, yet the microbial functions contributing to heterosis (hybrid vigor, the superior F1 performance versus inbred parents) under P limitation remain largely unknown. Here, we investigated rhizosphere microbiome assembly across 93 maize hybrid-inbred triplets grown under contrasting P conditions. Integrating plant performance, phosphorus accumulation, and the microbial abundance identified Sphingobium as a bacterial taxon consistently enriched in hybrid rhizospheres under P deficiency. A hybrid-enriched Sphingobium isolate (W6) preferentially promoted hybrid growth under low-P conditions, enhancing lateral root development, phosphorus acquisition, and biomass heterosis. Inhibition of auxin transport by N-1-naphthylphthalamic acid (NPA) abolished the W6-mediated growth promotion, whereas DR5::GUS assays and transcriptomic analyses revealed enhanced auxin responses following W6 inoculation. Genome analysis further identified the indole-3-pyruvate pathway as the predominant route for auxin biosynthesis in W6. Together, our findings demonstrate that a hybrid-enriched rhizobacterial function promoting auxin-dependent root architectural plasticity, rather than phosphorus mobilization alone, contributes to maize heterosis under phosphorus deficiency, providing mechanistic insight into how host–microbiome interactions improve crop adaptation to nutrient-limited environments.

The precise regulation of nitrogen supply after anthesis for maize can be achieved by blending urea and controlled-release urea (CCU) one-off application. However, the dynamic optimization governing source-sink allocation and patterns underlying synergistic carbon–nitrogen regulation remain poorly understood. We investigated the physiological and molecular mechanisms associated with carbon and nitrogen metabolism in maize under various controlled-release urea and conventional urea treatments. The experiment included five fertilization treatments: CK (no nitrogen) and four treatments at 180 kg N ha−1: U (all Urea-N), C1 (CRU-N: Urea-N = 1:2), C2 (CRU-N: Urea-N = 2:1), and C3 (all CRU-N). Physiological traits were measured, and integrated leaf transcriptomic and metabolomic analyses were conducted. Compared with urea treatment, CCU (C2 treatment) boosted maize yield by up to 18.3–22.8

Organic substitution for chemical phosphorus (P) fertilizers in acidic soils has yielded controversial results regarding soil P availability, primarily due to insufficient understanding of microbial mediation mechanisms. Based on a 13-year field trial in an acidic tea plantation, we investigated how varying rates of organic P substitution (0%, 38%, 65%, and 100%) alter P bioavailability and the associated microbial processes. Long-term organic substitution significantly enhanced microbial P transformation capacity, with 100% substitution increasing alkaline phosphatase (ALP) activity by 126% and elevating the abundances of P-cycling genes (bpp, phoD, ppx, pqqC, and phnK) by 1.1—1.2 fold compared to chemical fertilization. Microcosm experiments demonstrated that soil microbes under organic substitution mineralized recalcitrant organic P 2.3 times more efficiently. High-throughput sequencing revealed that organic substitution increased the diversity and altered the composition of phoD-harboring microbial communities. Network analysis and correlation studies identified Methylobacterium and Bradyrhizobium as keystone taxa driving P mineralization, with Methylobacterium abundance strongly correlating with tea shoot P concentration. Partial least squares path modeling confirmed that organic substitution indirectly enhanced plant P uptake primarily through reshaping keystone microbial taxa rather than through direct physicochemical effects. This study highlights a potential ecological link between organic P substitution, phoD-harboring microbiome restructuring, and P bioavailability in acidic tea plantation soil, providing baseline insights for microbiome-targeted strategies to improve P use efficiency in similar agroecosystems.

Introduction This study aimed to investigate the effects of nitrification inhibitors (NIs), specifically DMPP (Dimethyl pyrazole phosphate) and DMPFA (Dimethyl pyrazole fulvic acid), and plant growth-promoting microorganisms (PGPM) on nutrient uptake, allocation, and plant growth in maize under low phosphorus (P) availability. The research questions explored whether NIs enhance P, manganese (Mn), and zinc (Zn) uptake through rhizosphere acidification, alter nutrient partitioning between roots and shoots, and whether DMPFA-PGPM combinations synergistically improve plant growth and nutrient acquisition. Methods Two rhizobox experiments were conducted using silt loam soil with low P content (8.7 mg kg(-1) P-CAL, pH 6.4).Results In the first experiment, maize was subjected to ten treatments, including ammonium (NH4 +) and nitrate (NO3 -) with or without DMPP, DMPFA, and rock phosphate (RP), compared to controls. The second experiment tested five treatments, including NH(4 + )with DMPFA, fulvic acid, and Bacillus atrophaeus (ABi05) as PGPM. Measurements included rhizosphere pH, acid/alkaline phosphatase activity, root exudates, phytohormones, root morphology, plant biomass, and nutrient (P, Mn, Zn, Fe, Ca, Mg, K) concentrations in shoots and roots. Nutrient use efficiencies (PUE, PFPp, NRE) were calculated, and data were analyzed using one-way ANOVA with Fisher's LSD test (p<0.05). In the first experiment, DMPP+RP and DMPFA+RP treatments increased biomass by 31.8% and 38.5%, respectively, compared to the negative control, with total root length rising by up to 169.5% in the positive control (NO3 -+soluble P). Shoot Fe content was 60% higher in NI treatments, with Mn and Zn shoot concentrations increasing by up to 40.4% and 32.8%, respectively, in DMPFA treatments. The rhizosphere pH dropped by 0.5 units in NI treatments, thereby enhancing acid phosphatase activity. In the second experiment, DMPFA and DMPFA+ABi05 increased shoot biomass by 47.5% and 50.7%, respectively, and shoot P content by 45.1% and 62.7%. PUE was 56.2% higher with DMPFA+ABi05, and zeatin concentrations rose by 79.1% compared to controls. Conclusion DMP-based NIs significantly enhance P, Mn, and Zn uptake in maize by acidifying the rhizosphere and increasing nutrient solubility. NIs shift mainly Fe and Mn allocation toward shoots, improving nutrient mobilization. The synergistic effect of DMPFA and PGPM (ABi05) further boosts PUE and Zeatin.