Search Results (55)

The study aimed to investigate the effect of soil textural or soil mineral fraction substrates (loam and gravel) from karst desertification areas on the rhizospheric and root-associated bacterial community structure of Dalbergia odorifera (an N-fixing tree), using high-throughput sequencing techniques, based on treatment methods of whole-root and two-chambered split-root systems. Further, this study determined the relative importance of the plant and substrate properties on the rhizospheric, non-rhizospheric and endospheric bacteria composition. The type of substrate exerts a significant influence on both rhizospheric and non-rhizospheric bacterial communities, whereas endophytic communities within the root system are predominantly determined by plant species rather than substrate type. The analysis revealed that endospheric bacterial diversity was considerably lower than that of rhizospheric and non-rhizospheric communities. Cluster analysis indicated that endospheric bacterial samples formed a distinct cluster, while rhizospheric and non-rhizospheric bacteria in the soil substrate grouped into one branch, and those in the gravel substrate formed another branch. In comparison to the gravel treatments, a reduced bacterial abundance was observed in the rhizosphere and non-rhizosphere of nitrogen-fixing plants in soil, potentially due to the interplay of lower nutrient availability and increased porosity in gravel treatments. Proteobacteria, which are involved in the nitrogen cycle, exhibited the highest abundance. In contrast, Acidobacteria, Firmicutes and other bacterial phyla involved in nutrient cycling demonstrated higher abundance, with their presence being more pronounced in extreme environments, such as gravel treatments, compared to soil substrates. These results suggest that nitrogen-fixing plants can respond to extreme environments by increasing bacterial abundance. The findings of this study provide a theoretical basis for the use of D. odorifera for ecosystem recovery and vegetation restoration. Full article

Mixing and matching N₂-fixing leguminous species is a crucial strategy to enhance quality and efficiency in sustainable forestry. Tree leaves and rhizosphere are primary sites for matter and energy exchange, functioning as key assimilation organs that forests provide for ecological services. The introduction of functional species alters soil properties, which, in turn, directly or indirectly shape leaf functional traits, soil microbial dynamics, and their association. However, the correlation between aboveground functional traits and belowground rhizosphere soil microorganisms of dominant tree species in mixed leguminous and non-leguminous forests remains unclear. In this study, the responses and correlations of leaf functional traits and rhizosphere soil microbial communities of Castanopsis hystrix Hook. f. & Thomson ex A. DC. across three forest types were investigated. A pure forest (PF) of C. hystrix was designated as control forest, while a leguminous mixed forest (LMF) consisting of C. hystrix and the leguminous species Acacia mangium Willd. as well as a non-leguminous mixed forest (NMF) comprising C. hystrix and the non-leguminous species Schima superba Gardner & Champ. served as experimental forests. Seven leaf functional trait indices were measured, and the high-throughput sequencing of soil microbial communities was included in the analysis. The results were as follows: Firstly, compared to the pure forest, the specific leaf area (SLA) of C. hystrix significantly decreased in both mixed forest types (p < 0.05). Additionally, in comparison to the pure forest, the leaf area (LA) and leaf organic carbon content (LOC) of C. hystrix significantly reduced (p < 0.05), whereas the leaf total phosphorus content (LTP) significantly increased in the non-leguminous tree species mixed forest (p < 0.01). The leaf dry matter content (LDMC), relative chlorophyll content (RCC), and leaf total nitrogen content (LTN) of C. hystrix exhibited no significant differences among the three forest types (p > 0.05). Secondly, neither the dominant phyla of rhizosphere soil microorganisms nor the bacterial richness and diversity had differences in the mixed forests. However, the richness and diversity of rhizosphere soil fungi significantly increased in the mixed forests, and those in the leguminous mixed forest exhibited more positive effects compared to those in the non-leguminous mixed forest. Finally, redundancy analysis (RDA) showed significant correlations between plant leaf functional traits and rhizosphere soil microorganisms. Specifically, LDMC, SLA, LTN, and LTP of C. hystrix showed significant correlations with differences in the structure of bacterial community (p < 0.05), and LTN was significantly correlated with differences in the structure of the fungal community (p < 0.05). In summary, we found that plant leaf functional traits and the community of rhizosphere soil microorganisms displayed significant differences in the mixed forests, and those mixed with leguminous trees may further enhance the assimilation processes by modifying the utilization of nutrients such as carbon, nitrogen, and phosphorus by plants and microorganisms. Meanwhile, our results support the interaction of physiological and ecological processes between the aboveground and belowground parts of C. hystrix. These findings emphasize the important roles of N₂-fixing leguminous trees and synergy of aboveground–belowground processes in establishing sustainable artificial forests. Full article

This study presents the results of two on-farm trials evaluating the efficacy of a nitrogen (N)-fixing inoculant (Methylobacterium symbioticum) applied as a foliar spray to provide N to hazelnut (Corylus avellana L.) and walnut (Juglans regia L.) trees. In the hazelnut trial, a factorial design was employed with soil N application at three levels [0 (N0), 40 (N40), and 80 (N80) kg ha⁻¹] and foliar application of the inoculant (Yes and No). The walnut trial was arranged as a completely randomized design with three treatments: the N-fixing microorganism, a seaweed extract, and a control. Soil N application significantly increased hazelnut yield in 2021 (1.99, 2.49, and 2.65 t ha⁻¹ for N0, N40, and N80, respectively) but not in 2022 (average values ranging from 0.28 to 0.33 t ha⁻¹). The inoculant application did not significantly affect hazelnut yield. In the walnut trial, no significant differences were observed among the treatments in either year. The average yields ranged from 1.72 to 2.38 t ha⁻¹ in 2021 and 0.66 to 0.84 t ha⁻¹ in 2022. Soil N application in hazelnuts tended to increase leaf N concentration and significantly increased kernel N concentration. The inoculant increased leaf N concentration in one of the three sampling dates but did not affect kernel N concentration. In walnuts, the inoculant did not increase leaf N concentration but significantly increased kernel N concentration in one of the two years. The seaweed extract did not influence walnut yield or leaf N concentration. None of the treatments in either trial consistently affected the concentration of other macronutrients and micronutrients in the leaves. Therefore, while the inoculant showed some potential to improve the N nutritional status of the trees, it did not affect the yield. Overall, the results of the inoculant application were not sufficiently compelling, indicating the need for further studies on these species before the commercial product can be confidently recommended to farmers. Full article

The mixing of poplar and robinia in coastal saline land is a useful attempt at difficult site afforestation. Investigating the long–term mixing effects of nitrogen–fixing and non–nitrogen–fixing tree species on the spatial heterogeneity of N and P nutrients and their ecological stoichiometric characteristics in the coastal saline–alkali soil can provide a scientific basis for soil improvement and plantation management in the coastal saline–alkali soil. By replacing time with space, poplar and robinia mixed forests and corresponding pure forests with the ages of 3, 7 and 18 years were selected, and soil profiles of 0–20 cm, 20–40 cm and 40–60 cm were dug up to determine the contents of total nitrogen, hydrolyzed nitrogen, total phosphorus and available phosphorus, the activities of soil urease and phosphatase and the number of soil bacteria, fungi and actinomycetes in rhizosphere soil. The mixture of poplar and robinia and the increase in planting years led to the heterogeneity of soil N and P in a coastal saline–alkali forest, which could significantly increase the contents of soil total nitrogen, hydrolyzed nitrogen, total phosphorus and available phosphorus between soil layers. Compared with the pure forest of poplar and robinia at the same age, the soil urease activity in the 0–20 cm soil layer of an 18a poplar and robinia mixed forest increased by 94.75% and 73.36%, and the soil phosphatase activity increased by 30.36% and 70.27%. The mix of poplar and robinia significantly increased the abundance of soil microorganisms in saline–alkali soil. The number of bacteria, fungi and actinomycetes in the 0–20 cm soil layer of the 18a poplar and robinia mixed forest was the highest, which were 703,200, 31,297 and 1903, respectively. Redundancy analysis showed that there was a significant positive correlation between soil N and P nutrient contents, soil enzyme activities and microbial abundance. The soil depth of N and P nutrient decomposition and transformation in the mixed poplar and robinia plantation was expanded. The soil N and P nutrient contents, enzyme activities and microbial abundance in the 40–60 cm soil layer of the mixed forest were higher than those of the pure forest. With the increase in plantation years, the depth of soil that can be used in the forest land is increasing. The mixture of poplar and robinia plantation is an excellent choice for the construction of coastal saline–alkali land plantation, which has a significant mixed gain for the decomposition and transformation of N and P nutrients and increases the depth of the available soil layer in the forest land in coastal saline–alkali land. However, the coastal saline–alkali land soil N/P is < 14 and is still restricted by nitrogen, so the application of nitrogen fertilizer can be increased during the afforestation process. Full article

The glomalin-related soil protein (GRSP) is an important component of soil organic carbon (SOC), which plays an important role in maintaining soil structural stability, soil carbon (C), and nitrogen (N) fixation. However, little is known about the GRSP content in soil and its contribution to soil nutrients in plantations of different tree species. In this study, we determined the soil physicochemical characteristics and GRSP contents in different soil layers of four kinds of plantations, including Acacia mangium (AM), Pinus caribaea (PC), Eucalyptus urophylla (EU), and Magnoliaceae glanca (MG), to address how the plantation types affected the GRSP in different layers of soil in southern China. The results showed that with an increase in soil depth, the GRSP content decreased linearly, and the contribution rate of GRSP to SOC and total nitrogen (TN) in deep soil was 1.08–1.18 times that in surface soil. The tree species significantly affected the vertical distribution of GRSP in soil. Among the four plantations, the conifer species PC had the highest level of GRSP, while the N-fixing species AM had the lowest level. However, SOC, soil capillary porosity (CP), TN, soil water content (SWC), and total phosphorus (TP) were important factors regulating soil GRSP content. Additionally, the regulation effects of soil properties on GRSP were various in surface and deep soil among different plantations. In order to improve soil quality and C sequestration potential, conifer species can be planted appropriately, or conifer species and N-fixing species can be mixed to increase soil nutrient content and enhance soil structure and function in afforestation of southern China. Full article

Mixed forests created by incorporating nitrogen-fixing tree species offer enhanced ecological advantages compared with forests consisting of only one type of tree species. These benefits include habitat rehabilitation and the promotion of biodiversity. Nevertheless, the impact of introducing nitrogen-fixing tree species on ecosystem carbon (C), nitrogen (N), and phosphorus (P) sequestration and storage capacity in the Loess Plateau of China remains inadequately explored. To examine changes in the sequestration and storage capacity of ecosystem C, N, and P, the mixed plantations of P. tabulaeformis and H. rhamnoides (H_rP_t) were selected as the research object, and the pure plantations of H. rhamnoides (H_r) and P. tabulaeformis (P_t) were selected as the control. The results indicated that in comparison to the pure forest, the ecosystem in H_rP_t significantly increased C and N stocks but decreased P stocks. In addition, C, N, and P stocks in the soil layer accounted for more than 60% of the C, N, and P stocks in the pure and mixed forest ecosystems compared with the vegetation layer. Moreover, H_rP_t significantly improved ecosystem C and N sequestration rates relative to the pure forest but decreased P sequestration rates. Furthermore, the soil physicochemical properties can be inferred from the redundancy analysis showing 66.79% and 0.06% in H_r, 44.84% and 0.06% in P_t, as well as 44.28% and 0.04% in H_rP_t, respectively. In conclusion, compared with the pure forest, the introduction of N-fixing tree species was more conducive to the accumulation of C and N. The results offer substantial significance for the scientific guidance of vegetation restoration in degraded landscapes and the stewardship of mixed forests in the Loess Hilly Region, providing essential data for nutrient storage in ecosystems. Full article

Soil N-fixing bacterial (NFB) community may facilitate the successful establishment and invasion of exotic non-nitrogen (N) fixing plants. Invasive plants can negatively affect the NFB community by releasing N during litter decomposition, especially where N input from atmospheric N deposition is high. This study aimed to quantitatively compare the effects of the invasive Rhus typhina L. and native Koelreuteria paniculata Laxm. trees on the litter mass loss, soil physicochemical properties, soil enzyme activities, and the NFB. Following N supplementation at 5 g N m⁻² yr⁻¹ in four forms (including ammonium, nitrate, urea, and mixed N with an equal mixture of the three individual N forms), a litterbag-experiment was conducted indoors to simulate the litter decomposition of the two trees. After four months of decomposition, the litter cumulative mass losses of R. typhina under the control, ammonium chloride, potassium nitrate, urea, and mixed N were 57.93%, 57.38%, 58.69%, 63.66%, and 57.57%, respectively. The litter cumulative mass losses of K. paniculata under the control, ammonium chloride, potassium nitrate, urea, and mixed N were 54.98%, 57.99%, 48.14%, 49.02%, and 56.83%, respectively. The litter cumulative mass losses of equally mixed litter from both trees under the control, ammonium chloride, potassium nitrate, urea, and mixed N were 42.95%, 42.29%, 50.42%, 46.18%, and 43.71%, respectively. There were antagonistic responses to the co-decomposition of the two trees. The litter mass loss of the two trees was mainly associated with the taxonomic richness of NFB. The form of N was not significantly associated with the litter mass loss in either species, the mixing effect intensity of the litter co-decomposition of the two species, and NFB alpha diversity. Litter mass loss of R. typhina was significantly higher than that of K. paniculata under urea. The litter mass loss of the two trees under the control and N in four forms mainly affected the relative abundance of numerous NFB taxa, rather than NFB alpha diversity. Full article

Soil quality (SQ) pertains to the intricate and ongoing capacity of soil to function as a thriving ecosystem that supports the growth of plants and animals. However, there is a limited understanding of SQ assessment in mixed forest plantations. Therefore, we formulated and tested the hypothesis that the inclusion of a nitrogen-fixing tree species (such as Acacia mangium) improves SQ indicators in mixed treatments involving Eucalyptus trees. To evaluate the changes in SQ, we conducted a field experiment that employed the Soil Management Assessment Framework (SMAF) tool to analyze pure and mixed plantations of Eucalyptus grandis and A. mangium. Soil samples were collected at a depth of 0–20 cm from different treatments, including pure E. grandis without nitrogen fertilization (E), pure A. mangium (A), pure E. grandis with nitrogen fertilization (E + N), and mixed E. grandis and A. mangium (E + A). Sampling took place at 27 and 39 months after planting. We selected seven indicators of SQ: two biological indicators (soil microbial biomass carbon and β-glucosidase enzyme activity), four chemical indicators (soil organic carbon, pH, available phosphorus, and potassium), and one physical indicator (bulk density). By applying the SMAF tool, we determined the SQ scores for each indicator. The results revealed that E + A stands exhibited higher SMAF scores than pure stands, particularly in terms of pH (0.49 and 0.52 at 27 and 39 months, respectively) and phosphorus levels (0.84 and 0.82, at 27 and 39 months), respectively. Forest management practices and the sampling period had the most pronounced impact on biological and chemical indicators. Notably, significant positive correlations were observed between SMAF scores and pH, available phosphorus content, enzymes, soil organic carbon, and microbial biomass in both sampling periods. This study effectively provided novel information that introducing a nitrogen-fixing tree species in combination with eucalyptus trees enhances SQ, as indicated by the SMAF tool, which could reduce the need for external inputs (e.g., mineral fertilizers) by the farmers. Future studies should analyze the effects of A. mangium not only with other E. grandis varieties but also with other forestry essences. Full article

The aim of this incubation experiment was to evaluate the effect of Tenebrio molitor L. frass on selected chemical and microbiological properties of acid peat. The optimal rate of mealworm frass in the substrate for growing ornamental trees and shrubs was determined. Acid peat was fertilized with frass or urea at five nitrogen (N) rates: 0, 50, 100, 200, and 400 mg dm⁻³. Mineral N content and electrical conductivity increased, and calcium content decreased in peat with increasing N rates. Similarly to urea, frass increased the ammonification rate at the beginning of incubation and the nitrification rate from the second week of incubation. Higher frass rates increased the abundance of plant-available nutrients (N, P, Mg, K, and Na) in acid peat. Frass undesirably decreased the counts of bacteria with antagonistic activity against soil-borne plant pathogens. Regarding the abundance of functional genes, the optimal N rate was 100 mg dm⁻³, which promoted the growth of N-fixing and chitinolytic bacteria. Higher N rates promoted the development of aerobic spore-forming bacteria, which produce antibiotics that can be used as biocontrol agents. Moderate fertilizer rates contributed to N accumulation in bacterial biomass. These preliminary findings, which indicate that insect frass can partially replace mineral fertilizers, are promising and can be used in pot and field experiments testing various plant species. Full article

The genus Acacia is a crucial source of industrial papermaking and timber, possessing significant economic value. Due to their nitrogen-fixing ability, rapid growth, and high tolerance to stress, Acacia species have become integral to short-term industrial timber forests, particularly in southern China and various other regions worldwide. Nevertheless, comparative genomic analyses of Acacia species remain limited, impeding the development of molecular markers for identifying and distinguishing between distinct Acacia species as well as distinguishing their wood counterparts from other tree species. To address this gap, we generated plastomic sequences from eight species commonly cultivated in Chinese plantation forests and compared them with existing data. Our findings revealed a generally conserved structure and gene content within the plastid genomes of Acacia. Notably, the dN/dS ratio of genes from distinct functional groups varied, particularly between ribosomal proteins and photosynthesis genes. Furthermore, phylogenetic analyses and sequence comparisons suggest that the introduction of Acacia to China may have been less diverse than previously thought or that interspecies introgression has occurred more frequently than previously documented. This study offers a valuable starting point for future research in this area and for improving timber quality through marker-assisted breeding. Full article

The enhancing effect of N₂-fixing bacterial strains in the presence of mineral N doses on maize plants in pots and field trials was investigated. The OT-H1 of 10 isolates maintained the total nitrogen, nitrogenase activities, IAA production, and detection of NH₃ in their cultures. In addition, they highly promoted the germination of maize grains in plastic bags compared to the remainder. Therefore, OT-H1 was subjected for identification and selected for further tests. Based on their morphological, cultural, and biochemical traits, they belonged to the genera Azotobacter. The genomic sequences of 16S rRNA were, thus, used to confirm the identification of the genera. Accordingly, the indexes of tree and similarity for the related bacterial species indicated that genera were exactly closely linked to Azotoacter salinestris strain OR512393. In pot (35 days) and field (120 days) trials, the efficiencies of both A. salinestris and Azospirillum oryzea SWERI 111 (sole/dual) with 100, 75, 50, and 25% mineral N doses were evaluated with completely randomized experimental design and three repetitions. Results indicated that N₂-fixing bacteria in the presence of mineral N treatment showed pronounced effects compared to controls. A high value of maize plants was also noticed through increasing the concentration of mineral N and peaked at a dose of 100%. Differences among N₂-fixing bacteria were insignificant and were observed for A. oryzea with different mineral N doses. Thus, the utilization of A. oryzea and A. salinestris in their dual mix in the presence of 75 followed by 50% mineral N was found to be the superior treatments, causing the enhancement of vegetative growth and grain yield parameters of maize plants. Additionally, proline and the enzyme activities of both polyphenol oxidase (PPO) and peroxidase (PO) of maize leaves were induced, and high protein contents of maize grains were accumulated due to the superior treatments. The utilization of such N₂-fixing bacteria was, therefore, found to be effective at improving soil fertility and to be an environmentally safe strategy instead, or at least with low doses, of chemical fertilizers. Full article

The extracellular enzyme activity (EEA) and enzymatic stoichiometry (EES) of soil are useful indicators of shifts in soil nutrition and microbial resource requirements. Nevertheless, it is uncertain how the limitation of soil microbial nutrients is altered by a Eucalyptus plantation mixed with a N₂-fixing tree species. Our study examined the microbial nutrient limitation in two plantations: a pure Eucalyptus plantation (PP) and a mixed plantation (Eucalyptus and Erythrophleum fordii, MP) in rhizosphere and non-rhizosphere soils, beginning with two indicators, soil EEA and EES. In this study, the soil EEA was considerably (p < 0.05) greater in the MP contrasted to the PP, and the enzyme C:N:P ratios of the PP (1.12:1:1.10) and MP (1.07:1:1.08) both diverged from the global average EEA (1:1:1), and the deviation degree of the PP was greater. The results of the vector analysis demonstrated that the vector angle (VA) and vector length (VL) were considerably (p < 0.05) smaller in the MP contrasted to the PP. In comparison to the PP, the MP had a considerably (p < 0.05) poorer carbon quality index (CQI). Additionally, both microbial and soil properties have a considerable impact on soil EEA and EES, according to variance partitioning analysis (VPA) and redundancy analysis (RDA). In summary, our results show that the restriction of microorganisms on C and P in rhizosphere soils is usually weaker than that in non-rhizosphere soils and that the addition of N₂-fixing tree species to Eucalyptus plantations can lessen but not completely remove the restriction of soil microorganisms on C and P. Future management practices involving mixed plantations with N₂-fixing trees species could help decrease microbial nutrient limitation and promote sustainable plantations. Full article

This work was aimed at the characterization of residual generated biomass from pruned tree species present in the Andean areas of Ecuador as a source of energy, both in plantations and in urban areas, as a response to the change in the energy matrix proposed by the Ecuadorian government. From the proximate analysis (volatiles, ashes, and fixed carbon content), elemental analysis (C, H, N, S, O, and Cl), structural analysis (cellulose, lignin, and hemicellulose content), and higher heating value, the studied species were pine (Pinus radiata), cypress (Cupressus macrocarpa), eucalyptus (Eucalyptus globulus), poplar (Populus sp.), arupo (Chionanthus pubescens), alder (Alnus Acuminata), caper spurge (Euphorbia laurifolia), and lime (Sambucus nigra L.) trees. We evaluated the influence of the presence of leaves in the biomass. From this characterization, we developed a method based on obtaining the main components for the identification of the biomass’s species. If the origin of the biomass was unknown, this method enabled us to identify the species, with all its characteristics. If the origin of the biomass was unknown, this innovative method enabled the identification of the species from the lignocellulosic biomass, with all of its characteristics. Finally, we developed regression models that relate the higher heating value to the elemental, proximate, and structural composition. Full article

Intercropping perennial legumes with trees can reduce Nitrogen (N) losses, due to the high amount of N accumulated in stable forms in the soil and permanent soil cover during the whole year. Although N cycling improvement in mature agroforestry systems (AFS) was well documented, there is a lack of knowledge regarding systems in transition to AF. In this work, we studied the association of two perennial forage crops, namely ryegrass (Lolium multiflorum Lam.) and sulla (Hedysarum coronarium L.), with 1-year old poplars, to evaluate: (i) the agronomic performance of sulla and ryegrass with vs. without intercropped poplar trees; (ii) the N-fixing ability of sulla in association with trees; (iii) the N transfer effect from sulla and growth promoting effect on poplar; and finally (iv) the nitrate leaching reduction due to the presence of poplar trees associated to forage crops. The layout was arranged in a two-factor randomized complete blocks design (RCB) with three replicates. The first factor tested (crop species) implied two different swards, namely sulla and ryegrass. The second factor (cropping system) included two different systems: PAST i.e., a pastoral system without trees, and SIPAST, i.e., a silvo-pastoral system with one poplar tree row beside the sward. Sulla resulted more productive than ryegrass when associated with trees (+35%). No clear trend was observed about the tree influence on N-fixation in sulla, but the amount of N fixed resulted higher in in sulla grown in the SIPAST near the trees (+35%). Poplar plants, even in the first year after planting, resulted effective yet in reducing the nitrate flux from the crops towards ditches. Further investigations are needed to study other swards in young AF and better understand the N dynamics; in particular, it could be worth to assess the nutrient flux in the soil solution. Full article

Mixed-species plantations of trees with N-fixing species have the potential of promoting forest productivity and soil fertility. However, few studies in the literature have addressed the advantages of mixed-species plantations of leguminous trees over monocultures of leguminous trees based on in situ inventories over a long time period. Here, we monitored the dynamics of tree community composition, vegetation biomass, soil nutrients, and soil microbial phospholipid fatty acids (PLFAs), in an Acacia mangium monoculture plantation during 33 years of development and compared it with a mixed-species plantation of A. mangium associated with 56 native species which were underplanted 14 years after the initial establishment. Leaf N and phosphorus (P) concentrations of three main species in the overstory and understory of the A. mangium monoculture were measured. Our results showed that the soil organic carbon (SOC), total nitrogen (TN), and available phosphorus (AP) concentrations significantly increased over time during the approximately thirty years of A. mangium monoculture plantation, while the disadvantages were associated with new species regeneration and the increment of vegetation biomass. In the A. mangium monoculture plantation, leaf N concentration of A. mangium,Rhodomyrtus tomentosa, and Dicranopteris dichotoma continuously increased from 21 to 31 years, while the leaf P concentration of A. mangium and R. tomentosa decreased. The mixed-species plantations of A. mangium with native tree species had lower SOC and soil TN concentrations, more new tree species recruitment in the understory, and faster vegetation biomass increment than the A. mangium monoculture. However, the PLFAs of soil microbial groups were slightly different between the two types of plantations. We conclude that improved soil N nutrient condition by A. mangium monoculture benefits N absorption by A. mangium, R. tomentosa, and D. tomentosa, while low soil AP limits P absorption by A. mangium and R. tomentosa. Meanwhile, transforming the A. mangium monoculture into a mixed-species plantation via the introduction of multiple native species into the A. mangium monoculture decreases SOC and TN concentrations but the advantages include improving forest regeneration and maintaining forest growth in a long-term sequence. These findings provide useful and practical suggestions for managing forest monocultures of A. mangium in subtropical regions. Full article