Search Results (315)

Carbon (C) sequestration and nitrogen (N) and phosphorus (P) accumulation in urban forest green spaces are significant for global climate regulation and alleviating nutrient pollution. However, the effects of management and conservation practices across different urban forest vegetation types on soil C, N, and P contents and stoichiometric ratios remain largely unexplored. We selected forest soils from Guangzhou, a major Metropolis in China, as our study area. Soil samples were collected from two urban secondary forests that naturally regenerated after disturbance (108 samples) and six urban forest parks primarily composed of artificially planted woody plant communities (72 samples). We employed mixed linear models and variance partitioning to analyze and compare soil C, N, and P contents and their stoichiometry and its main driving factors beneath suburban forests and urban park vegetation. These results exhibited that soil pH and bulk density in urban parks were higher than those in suburban forests, whereas soil water content, maximum storage capacity, and capillary porosity were higher in urban forests than in urban parks. Soil C, N, and P contents and their stoichiometry (except for N:P ratio) were significantly higher in suburban forests than in urban parks. Multiple analyzes showed that soil pH had the most pronounced negative influence on soil C, N, C:N, C:P, and N:P, but the strongest positive influence on soil P in urban parks. Soil water content had the strongest positive effect on soil C, N, P, C:N, and C:P, while soil N:P was primarily influenced by the positive effect of soil non-capillary porosity in suburban forests. Overall, our study emphasizes that suburban forests outperform urban parks in terms of carbon and nutrient accumulation, and urban green space management should focus particularly on the impact of soil pH and moisture content on soil C, N, and P contents and their stoichiometry. Full article

Eco-enzymatic stoichiometry provides a basis for understanding soil ecosystem functions, with implications for land management and ecological protection. Long-term climatic factors and human interferences have caused significant land-use transformations in the Qinghai–Tibet Plateau region, affecting various ecological functions, such as soil nutrient cycling and chemical element balance. It is currently unclear how large-scale land-use conversion affects soil ecological stoichiometry. In this study, 763 soil samples were collected across three land-use types: farmland, grassland, and forest land. In addition, changes in soil physicochemical properties and enzyme activity and stoichiometry were determined. The soil available phosphorus (SAP) and total phosphorus (TP) concentrations were the highest in farmland soil. Bulk density, pH, SAP, TP, and NO₃⁻-N were lower in forest soil, whereas NH₄⁺-N, available nitrogen, soil organic carbon (SOC), available potassium, and the soil nutrient ratio increased. Land-use conversion promoted soil β-1,4-glucosidase, N-acetyl-β-glucosaminidase, and alkaline phosphatase activities, mostly in forest soil. The eco-enzymatic C:N ratio was higher in farmland soils but grassland soils had a higher enzymatic C:P and N:P. Soil microorganisms were limited by P nutrients in all land-use patterns. C limitation was the highest in farmland soil. The redundancy analysis indicated that the ecological stoichiometry in farmland was influenced by TN, whereas grass and forest soils were influenced by SOC. Overall, the conversion of cropland or grassland to complex land-use types can effectively enhance soil nutrients, enzyme activities, and ecosystem functions, providing valuable insights for ecological restoration and sustainable land management in alpine regions. Full article

Integrated rice–crayfish (Oryza sativa–Procambarus clarkii) co-culture (RC) systems have gained prominence due to their economic benefits and ecological sustainability; however, the interactions between soil properties and microbial communities in such systems remain poorly understood. This study evaluated the effects of the RC systems on soil physicochemical characteristics and microbial dynamics in paddy fields of southern Henan Province, China, over the 2023 growing season and subsequent fallow period. Using a randomized complete design, rice monoculture (RM, as the control) and RC treatments were compared across replicated plots. Soil and water samples were collected post-harvest and pre-transplanting to assess soil properties, extracellular enzyme activity, and microbial community structure. Results showed that RC significantly enhanced soil moisture by up to 30.2%, increased soil porosity by 9.6%, and nearly tripled soil organic carbon compared to RM. The RC system consistently elevated nitrogen (N), phosphorus (P), and potassium (K) throughout both the rice growth and fallow stages, indicating improved nutrient availability and retention. Elevated extracellular enzyme activities linked to carbon, N, and P cycling were observed under RC, with enzymatic stoichiometry revealing increased microbial nutrient limitation intensity and a shift toward P limitation. Microbial community composition was significantly altered under RC, showing increased biomass, a higher fungi-to-bacteria ratio, and greater relative abundance of Gram-positive bacteria, reflecting enhanced soil biodiversity and ecosystem resilience. Further analyses using the Mantel test and Random Forest identified extracellular enzyme activities, PLFAs, soil moisture, and bulk density as major factors shaping microbial communities. Redundancy analysis (RDA) confirmed that total potassium (TK), vector length (VL), soil pH, and total nitrogen (TN) were the strongest environmental predictors of microbial variation, jointly explaining 74.57% of the total variation. Our findings indicated that RC improves soil physicochemical conditions and microbial function, thereby supporting sustainable nutrient cycling and offering a promising, environmentally sound strategy for enhancing productivity and soil health in rice-based agro-ecosystems. Full article

Elevational gradients in temperature, moisture, and vegetation strongly influence soil nutrient content and stoichiometry in mountainous regions. However, exactly how total, microbial, and enzymatic carbon (C), nitrogen (N), and phosphorus (P) stoichiometry vary with elevation in karst peak-cluster depressions remains poorly understood. To address this, we studied soil total, microbial, and enzymatic C:N:P stoichiometry in seasonal rainforests within karst peak-cluster depressions in southwestern China at different elevations (200, 300, 400, and 500 m asl) and depths (0–20 and 20–40 cm). We found that soil organic carbon (SOC), total nitrogen (TN), and the C:P and N:P ratios increased significantly with elevation, whereas total phosphorus (TP) decreased. Microbial phosphorus (MBP) also declined with elevation, while the microbial N:P ratio rose. Activities of nitrogen- (β-N-acetylglucosaminidase and L-leucine aminopeptidase combined) and phosphorus-related enzymes (alkaline phosphatase) increased markedly with elevation, suggesting potential phosphorus limitation for plant growth at higher elevations. Our results suggest that total, microbial, and enzymatic soil stoichiometry are collectively shaped by topography and soil physicochemical properties, with elevation, pH, and exchangeable calcium (ECa) acting as the key drivers. Microbial stoichiometry exhibited positive interactions with soil stoichiometry, while enzymatic stoichiometry did not fully conform to the expectations of resource allocation theory, likely due to the functional specificity of phosphatase. Overall, these findings enhance our understanding of C–N–P biogeochemical coupling in karst ecosystems, highlight potential nutrient limitations, and provide a scientific basis for sustainable forest management in tropical karst regions. Full article

Ochroma lagopus, a fast-growing tropical tree species, faces fertilization challenges due to slope heterogeneity in plantations. This study examined 3-year-old Ochroma lagopus at upper and lower slope positions under five treatments: CK (no fertilizer), F1 (600 g/plant), F2 (800 g/plant), F3 (1000 g/plant), and F4 (1200 g/plant) of secondary macronutrient water-soluble fertilizer. Growth parameters and N-P-K stoichiometry were analyzed. Key results: (1) Height increased continuously with fertilizer dosage at both slopes, while DBH peaked and then declined. (2) At upper slopes (nutrient-poor soil), fertilization elevated leaf P but reduced branch N/K and increased root P/K. At lower slopes (nutrient-rich soil), late-stage leaf N increased significantly, with roots accumulating P/K via a “storage strategy”. Stoichiometric thresholds indicated N-K co-limitation (early-mid stage) shifting to P limitation (late stage) on upper slopes and persistent N-K co-limitation on lower slopes. (3) PCA identified F4 (1200 g/plant) and F1 (600 g/plant) as optimal for upper and lower slopes, respectively. This research provides a theoretical basis for precision fertilization in Ochroma lagopus plantations, emphasizing slope-specific nutrient status and element interactions for dosage optimization. Full article

Replacing partial chemical fertilizers with organic fertilizer can increase organic carbon input, change soil nutrient stoichiometry and microbial metabolism, and then affect soil organic carbon (SOC) storage. A 6-year field experiment was used to explore the mechanism of SOC storage under different ratios of manure substitution in northeast China, with treatments including chemical fertilizer application alone (nitrogen, phosphorus, and potassium, NPK) and replacing 1/4 (1/4M), 2/4 (2/4M), 3/4 (3/4M), and 4/4 (4/4M) of chemical fertilizer N with manure N. Soil nutrients, enzymatic activity, and SOC fractions were analyzed to evaluate the effect of different manure substitution ratios on SOC storage. A high ratio of manure substitution (>1/4) significantly increased soil total N, total P, total K, and available nutrients (NO₃⁻-N, available P, and available K), and the 4/4M greatly decreased the C/N ratio compared to the NPK. Manure incorporation increased microbial biomass carbon (MBC) by 18.3–53.0%. Treatments with 50%, 75%, and 100% manure substitution (2/4M, 3/4M, and 4/4M) enhanced bacterial necromass carbon (BNC), fungal necromass carbon (FNC), and total microbial necromass carbon (MNC) by 31.9–63.5%, 25.5–107.1%, and 27.4–94.2%, respectively, compared to the NPK treatment. Notably, the increase in FNC was greater than that of BNC as the manure substitution ratio increased. The increasing manure substitution significantly enhanced particulate organic C (POC) and total SOC but did not affect mineral-associated organic C (MAOC). High soil N and P supplies decreased leucine aminopeptidases (LAPs) and alkaline phosphatase activities but increased the activity ratio of β-glucosidase (BG)/(N-acetyl-glucosaminidase (NAG) + LAP). Treatments with 25% manure substitution (1/4M) maintained maize and soybean yield, but with increasing manure rate, the maize yield decreased gradually. Overall, the high ratio of manure substitution enhanced SOC storage via increasing POC and MNC, and decreasing the decomposition potential of manure C and soil C resulting from low N- and P-requiring enzyme activities under high nutrient supplies. This study provides empirical evidence that the rational substitution of chemical fertilizers with manure is an effective measure to improve the availability of nutrients, and its effect on increasing crop yields still needs to be continuously observed, which is still a beneficial choice for enhancing black soil fertility. Full article

Cadmium and petroleum are the main pollutants in coastal wetland ecosystems that affect plant nutrient balance and growth. Scholars have discovered how saline plants adapt to single stresses. How plant ecology and physiology correspond to complex cadmium and petroleum pollution, especially regarding the pollution impacts on carbon (C), nitrogen (N), and phosphorus (P) stoichiometry and biomass allocation in coastal wetland plants, remains unclear, limiting their application in regard to pollution remediation. This study focuses on Suaeda salsa, a popular species used in vegetation restoration in the Yellow River Delta’s coastal wetlands. Through the use of pot experiments, the dynamic changes in plant–soil ecological stoichiometry and biomass allocation were systematically investigated in response to individual and combined cadmium (0, 5, and 10 mg kg⁻¹) and petroleum (0, 6, and 12 g kg⁻¹) treatments. Compared with the control (CK), petroleum stress significantly increased the total nitrogen (TN) and plant total phosphorus (TP) contents, but did not substantially impact the total carbon (TC) content, resulting in 19.7% and 26.6% decreases in the plant C/N and C/P ratios, respectively. The soil organic carbon (SOC) content increased significantly under petroleum stress, whereas the TN and TP contents did not notably change, considerably increasing the soil C/N and C/P ratios, which were 1.5 times and 1.3 times greater than those of the CK, respectively. Cadmium stress alone or with petroleum stress did not significantly affect the C, N, or P stoichiometry or biomass allocation in S. salsa. The soil C/N/P stoichiometry redundancy analysis revealed that the contribution rates (especially the soil C/P and C/N ratios) to the total biomass and its allocation in S. salsa (64.5%) were greater than those of the control group plants (35.5%). The correlation analysis revealed that the total growth biomass of S. salsa was negatively correlated with the soil carbon content, C/N ratio, and C/P ratio, but positively correlated with the plant C/N and C/P ratios. The aboveground biomass proportion in S. salsa was significantly negatively correlated with the soil N/P ratio. The belowground biomass proportion exhibited the opposite trend. Petroleum pollution was the main factor driving S. salsa stoichiometry and growth changes, increasing the soil C/N and C/P ratios, reducing the nitrogen and phosphorus nutrient absorption capacities in plant roots, limiting plant nitrogen and phosphorus nutrients, and inhibiting biomass accumulation. Appropriate N and P supplementation alleviated plant growth inhibition due to petroleum pollution stress, which was conducive to improving vegetation ecological restoration in the Yellow River Delta. Full article

Carbon (C), nitrogen (N), and phosphorus (P) act as pivotal regulators of biogeochemical cycles, steering organic matter decomposition and carbon sequestration in terrestrial ecosystems through the stoichiometric properties of photosynthetic organs. Deciphering their multi-scale spatiotemporal dynamics is central to unraveling plant nutrient strategies and their coupling mechanisms with global element cycling. In the current study, we modeled biogeochemical parameters (C/N/P contents, stoichiometry, and pools) in plant aboveground parts by using the growing mean temperature, total precipitation, total radiation, and maximum normalized difference vegetation index (NDVImax) across nine models (i.e., random forest model, generalized boosting regression model, multiple linear regression model, artificial neural network model, generalized linear regression model, conditional inference tree model, extreme gradient boosting model, support vector machine model, and recursive regression tree) in Xizang grasslands. The results showed that the random forest model had the highest predictive accuracy for nitrogen content, C:P, and N:P ratios under both grazing and fencing conditions (training R² ≥ 0.61, validation R² ≥ 0.95). Additionally, the random forest model had the highest predictive accuracy for C:N ratios under fencing conditions (training R² = 0.84, validation R² = 1.00), as well as for C pool and P content and pool under grazing conditions (training R² ≥ 0.62, validation R² ≥ 0.90). Therefore, the random forest algorithm based on climate data and/or the NDVImax demonstrated superior predictive performance in modeling these biogeochemical parameters. Full article

The transformation of degraded stands represents an essential strategy for enhancing stand productivity and optimizing site adaptability. This study examined four typical monoculture forest stands transformed from underperforming Platycladus orientalis (PO) forests in the limestone area of Xuzhou, China: Acer pictum subsp. mono (AP), Pistacia chinensis (PC), Ligustrum lucidum (LL), and Firmiana simplex (FS). The contents of carbon (C), nitrogen (N), and phosphorus (P), along with the C:N:P stoichiometric ratios, were analyzed in plants (leaves and fine roots), litter, and soil. The relationships among these components and their main influencing factors were explored. The results indicated that FS leaves contained higher levels of N and P, whereas LL litter presented significantly elevated C:N and N:P ratios in comparison with those of the other forest stands (p < 0.05). With the exception of FS, leaves displayed lower P than fine roots, which presented pronounced P enrichment. The soil C, N, and P contents decreased with depth, with both the forest stand and depth significantly impacting the soil stoichiometry (p < 0.01). Redundancy analysis identified available potassium, total nitrogen, and microbial biomass carbon in the soil as key factors influencing the stoichiometric characteristics of the leaf–fine root–litter continuum. Collectively, the leaf N:P ratios (>16) and low soil P contents indicate that plantation growth was primarily constrained by P limitation. In response, AP, PC, and LL allocate more P to fine roots to adapt to the environment. Full article

Phosphorus (P) is a pivotal element in plant energy metabolism and growth, and P limitation is widespread among plants in nature. However, our understanding of how epiphytes allocate P and adapt to P-deficient environments remains limited. We selected an obligate epiphyte Pyrrosia sheareri from a subtropical forest as our research subject. We compared its carbon (C)–nitrogen (N)–P ecological stoichiometry, P fractions, and morphological and physiological traits under the two habitats (trunk-epiphytic and rock-epiphytic). We also constructed a plant trait network method (PTN) that includes 62 traits to explore the co-variation characteristics of plant traits across the whole plant and identify the hub traits. We found that the following: (1) Habitat type significantly affects plant P concentration, with trunk-epiphytic plants having higher P concentration than rock-epiphytic plants. Pyrrosia sheareri may be more strongly limited by P according to the results of C-N-P ecological stoichiometry. (2) Epiphytic habitats significantly affect plant P fractions but do not influence the relative allocation of P fractions. (3) Compared with rock-epiphytic plants, trunk-epiphytic plants adopt a root resource-acquisition strategy rather than relying on leaves. (4) P-related indicators link ecological stoichiometry with morphological and physiological traits and are hub traits in PTN. Overall, P. plays a key functional role in the environmental acclimatization of Pyrrosia sheareri, highlighting the morphological and physiological adaptability of epiphytes to various habitats in terms of P availability, allocation, and storage. Full article

Soil amendments such as limestone and gypsum can influence microbial carbon use efficiency (CUE) by altering nutrient stoichiometry, particularly nitrogen (N) and phosphorus (P). However, their effects beyond the topsoil, especially under no-till systems, remain unclear. This study assessed microbial CUE through substrate use efficiency (SUE) following glucose addition as a factor influencing carbon (C) sequestration potential. Two experiments were conducted in tropical soil. The first evaluated the addition of ¹⁴C-glucose (G) to soil treated with lime, lime + gypsum, and a control, with or without the addition of N. The second compared limestone + gypsum and control treatments, incorporating G with N and P. Soil microbial respiration (CO₂ emission) was measured after 14 and 42 days. In the surface soil (0–10 cm), CUE increased with limestone or limestone + gypsum when N was applied. In the subsoil (40–60 cm), these amendments enhanced CUE compared to untreated soil in the absence of N. Treatments with G+N+P or G+P improved CUE in the surface soil. At the same time, G+N+P increased CUE in the subsoil regardless of acidity alleviation. Differences in ¹⁴CO₂ evolution indicated higher microbial CUE with acidity correction. Balanced N and P applications significantly enhanced CUE, highlighting the importance of both soil acidity correction and nutrient availability for microbial carbon processing. Full article

Despite extensive research on how climate and environmental factors influence leaf stoichiometry at national and global scales, experimental evidence on their effects at the community level remains limited, particularly in extremely arid regions. Herein, we investigated the leaf stoichiometry including carbon (C), nitrogen (N), and phosphorus (P) along a fine-scale riparian gradient (50–1250 m from the riverbank) in an extremely arid Populus euphratica forest in northwest China. Our results show that the community-averaged leaf total carbon (TC), total nitrogen (TN), and total phosphorus (TP) contents were 442.58 mg/g, 21.69 mg/g, and 1.18 mg/g, respectively. The community-averaged C:N, C:P, and N:P ratios were 20.74, 379.97, and 18.43, respectively. Compared to findings from other studies, the P. euphratica community exhibited lower leaf TC and TP contents but higher TN content and N:P ratios. A high N:P ratio (mean = 18.43, N:P > 16) suggests that the P. euphratica community is more susceptible to phosphorus limitation. Along the riparian gradient, community-averaged leaf TC, C:N, and C:P increased significantly, reaching their maximum (479.49 mg/g, 27.12, and 478.06, respectively) at 1250 m from the riverbank. Conversely, leaf TN and TP contents, as well as N:P, decreased significantly with increasing distance from the river, reaching their minimum values (17.49 mg/g, 0.99 mg/g, and 17.17, respectively) at 1100–1250 m. Soil available phosphorus, soil water content, soil bulk density, and soil electrical conductivity significantly influenced the leaf stoichiometry of the P. euphratica community, collectively explaining 61.78% of the total variation. Among these factors, soil water content had the most pronounced effect, surpassing soil available phosphorus, bulk density, and electrical conductivity in shaping leaf stoichiometric characteristics. Our findings indicate that at fine spatial scales, the distribution of leaf nutrients and stoichiometry seem to be predominantly influenced by local-scale factors such as soil water content, soil nutrient levels, and salt stress; P. euphratica forests would be experiencing more negative impacts in leaf nutrients and stoichiometry due to increased droughts or salt stress. Full article

The purpose of this study was to evaluate the effects of different nitrogen (N), phosphorus (P), and potassium (K) fertilization ratios on the carbon (C), N, and P contents and their ecological stoichiometric characteristics in the leaf–soil–microbial system of Sapindus saponaria and elucidate their relationship with yield. A “3414” experimental design was employed in a 6-year-old Sapindus saponaria woodland located in Fujian Province of China. Fourteen N–P–K fertilization treatments with three replicates were established. Leaf, soil, and microbial samples were collected and analyzed for C, N, and P contents. Redundancy Analysis (RDA), Partial Least Squares Path Modeling (PLS–PM), and the entropy-weighted technique of ranking preferences by similarity to optimal solutions (TOPSIS) were utilized to assess the relationships among variables and determine optimal fertilization strategies. It was found through research that different fertilization treatment methods have a significant impact on both the soil nutrient content and the C, N, and P contents of soil microorganisms. Compared with the control group, soil organic C, total N, and total P, and microbial C, N, and P contents increased by 14.25% to 52.61%, 3.90% to 39.84%, 9.52% to 150%, 6.65% to 47.45%, 11.84% to 46.50%, and 14.91% to 201.98%, respectively. Results from Redundancy Analysis (RDA) indicated that soil organic C, total N, and total P exerted a significant influence on the leaf nutrients. PLS-PM demonstrated that fertilization indirectly affected leaf nutrient accumulation and yield by altering soil properties, with soil total phosphorus and leaf phosphorus being key determinants of yield. Additionally, soil microbial entropy impacted yield by regulating microbial biomass stoichiometric ratios. The entropy-weighted TOPSIS model identified the N₂P₂K₂ treatment (600 kg/ha N, 500 kg/ha P, and 400 kg/ha K) as the most effective fertilization strategy. Optimizing N–P–K fertilization ratios significantly enhances leaf nutrient content and soil microbial biomass C, N, and P, thereby increasing Sapindus saponaria yield. This research clarifies the underlying mechanisms through which fertilization exerts an impact on the C–N–P stoichiometry within the leaf–soil–microbial system. Moreover, it furnishes a scientific foundation for the optimization of fertilization management strategies in Sapindus saponaria plantations. Full article

Crop rotation systems profoundly influence soil phosphorus (P) dynamics through physicochemical and microbial interactions. The mechanisms regulating P availability under various rotational practices remain poorly understood. This five-year field experiment investigated the effects of four rotation systems (WM: wheat–maize; WP: wheat–peanut; WS: wheat–soybean; MV: maize–hairy vetch) on soil P fractions, phosphatase activities, P-cycling gene abundance, and their interactions with soil properties. The WM rotation substantially reduced soil pH (6.29) while increasing labile P fractions (Ca₂-P) and moderately labile P (Al-P, Fe-P, and Ca₈-P), which was attributed to enhanced acid phosphatase activity. The WP rotation elevated soil pH (8.13) but reduced P availability due to calcium–P immobilization. The MV rotation stimulated microbial P cycling, exhibiting the highest phoD (2.01 × 10⁶ copies g⁻¹) and phnK (33,140 copies g⁻¹) gene abundance, which was linked to green manure-induced microbial activation. Redundancy analysis identified soil pH, total nitrogen, and stoichiometric ratios (C/N and N/P) as key shared drivers of P fractions and enzymatic activity. Partial least squares path modeling (PLS–PM) indicated that crop rotation directly regulated P availability through pH modulation (r = −0.559 ***) and the C/N ratio (r = 0.343 ***) while indirectly regulating P fractions through phosphatase activity. Lower C/N ratios (<10) across all rotation regimes amplified the carbon limitation in the process of P transformation, indicating that exogenous carbon inputs and appropriate stoichiometry in the soil should be optimized. The results of this study inform the selection of suitable crop rotation patterns for sustainable agriculture. Full article

Mongolian pine (Pinus sylvestris var. Mongolia) has been widely utilized as a key species for afforestation projects within the Three-North Shelterbelt of Liaoning Province in China. Its impressive ecological resilience has made it a favorite choice for this endeavor. However, as the stands mature and climate conditions shift, some areas are experiencing premature decline or even mortality. Ecological stoichiometry is capable of uncovering the supply and equilibrium of plant and soil nutrients within ecosystems and is extensively utilized in the identification of limiting elements. Therefore, studying its ecological stoichiometry and internal stability dynamics is of crucial significance for clarifying the nutrient cycling process in the Mongolian pine region and alleviating the decline situation. The eastern and northwestern regions of Liaoning differ significantly in precipitation and soil nutrient availability. This study examines Mongolian pine plantations in both regions, analyzing the carbon (C), nitrogen (N), and phosphorus (P) content in plant tissues, soil, microbial biomass, and stoichiometric ratio under distinct environmental conditions. In order to provide a theoretical basis for alleviating the decline of artificial poplar forests and healthy management. Results indicate that (1) leaf C, N, and P contents in the eastern Liaoning region averaged 496.67, 15.19, and 1.66 g·kg⁻¹, respectively, whereas those in northwestern Liaoning were 514.16, 14.82, and 1.23 g·kg⁻¹, respectively. Soil C, N, and P concentrations exhibited notable regional differences, with eastern Liaoning recording 34.54, 2.62, and 0.48 g·kg⁻¹, compared to significantly lower values in northwestern Liaoning (7.74, 0.77, and 0.21 g·kg⁻¹). Similarly, microbial biomass C, N, and P were higher in eastern Liaoning (18.63, 5.09, and 7.72 mg·kg⁻¹) than in northwestern Liaoning (10.18, 3.46, and 4.38 mg·kg⁻¹). (2) The stoichiometric ratio of soil in the Mongolian pine plantations is higher than that in northwestern Liaoning, but the stoichiometric ratio of plants shows the opposite trend. Specifically, microbial carbon-to-nitrogen (MBC/MBN) ratios are higher in eastern Liaoning, whereas microbial carbon-to-phosphorus (MBC/MBP) and nitrogen-to-phosphorus (MBN/MBP) ratios are greater in northwestern Liaoning. Correlation analysis of plant–soil–microbe stoichiometry indicates that plant growth in both regions is co-limited by nitrogen, with Mongolian pine exhibiting strong internal stability. Full article