Continuous cropping severely limits the sustainable production of watermelon (Citrullus lanatus L.) by inducing soil degradation, yet the mechanisms of microbial succession and interaction remain unclear. We monitored rhizosphere soils across 11 consecutive cropping seasons in a greenhouse pot experiment to evaluate the impact on bacterial and fungal communities. Available nitrogen, available potassium, total carbon, and total nitrogen declined with cropping duration, whereas available phosphorus showed a hump-shaped pattern. Soil pH reached a minimum in the seventh season, and soil enzyme activities increased markedly from the fifth season. Quantitative Real-time PCR (qPCR) and amplicon sequencing showed sustained rises in bacterial abundance, while fungal abundance initially decreased before recovering. Bacterial Shannon diversity hit a nadir in the fifth season with subsequent partial recovery, whereas fungal diversity continuously declined. Principal coordinate analysis (PCoA) revealed abrupt community shifts in both domains at the fifth season. Co-occurrence networks simplified sharply thereafter, with bacterial network complexity strongly negatively correlated with enriched Bacillus abundance (R² = 0.91). Structural equation modeling indicated that soil chemical changes and reduced fungal diversity were associated with increased Fusarium, whereas Bacillus enrichment did not suppress Fusarium. Sterilized soil bioassays confirmed that biotic factors induced broad-spectrum growth inhibition in both watermelon and tomato, suggesting broader microbial community imbalance. These results identify the fifth season as a critical threshold for Fusarium enrichment and network simplification, highlighting an actionable time window for early interventions to restore microbial functions before dysbiosis becomes entrenched.

Intensive management of Carya cathayensis (C. cathayensis) plantations has been linked to soil degradation and increased disease incidence, yet the underlying shifts in rhizosphere microbial communities remain poorly understood. We compared rhizosphere soils from non-managed forest(NF), reduced-management forest(RF), and intensive-management forest(IF) stands across two towns in Zhejiang, China. With increasing management intensity, soil fertility and enzyme activities declined, bacterial diversity and network stability decreased, whereas fungal diversity tended to increase. Bacterial community assembly was predominantly deterministic and became more so under intensive management, whereas fungal assembly remained largely stochastic. Management intensity did not directly regulate microbial assembly; instead, soil chemical properties and enzyme activities mediated these patterns. Several microbial taxa responded strongly to management intensity and were significantly correlated with community assembly processes. These findings reveal consistent associations between management intensity and rhizosphere microbial patterns across two landscapes, despite potential site-related variation. Reducing management intensity favours microbial network complexity and stability, offering microbiome-based avenues for sustainable C. cathayensis forestry.

Mitigating nitrous oxide (N2O) emissions from cropland soils is a pressing challenge for climate change mitigation. This study evaluated rockwool-based fertigation (RF) in reducing N2O emissions from tea plantations. A 17-month field experiment was conducted comparing RF with conventional surface fertilization (CK), measuring tea plant biomass, new tea shoots yield, new tea shoots quality indices, soil N2O fluxes, physicochemical properties, and nitrogen (N)-cycling functional genes across different soil layers. Results showed that RF treatment significantly increased the aboveground pruning biomass of tea plants, suggesting that RF promotes tea plant growth. The RF treatment showed lower N2O fluxes and cumulative N2O emissions within 90 days post-fertilization across the tea-growing season compared with CK, demonstrating that RF effectively mitigates N2O emissions from tea plantation soils. Random forest analysis further revealed that the RF-induced vertical redistribution of nutrients and N-cycling functional genes was the primary driver of N2O mitigation. Our findings demonstrate that RF is an effective dual-benefit strategy that simultaneously enhances tea plant productivity and mitigates N2O emissions by reshaping soil biogeochemical processes and their spatial distribution.

Microbial biocontrol agents (BCAs) play a critical role in maintaining plant health by antagonizing pathogens. However, most research has focused on direct suppression mechanisms (e.g., antibiosis and competition), while the neutralization of mycotoxin for disease management remains unexplored. Here, we report that a fungal BCA, Trichoderma harzianum (Th), subverts Fusarium verticillioides (Fv) infection via a fusaric acid (FSA) detoxification process in maize. Salicylate hydroxylase was found to detoxify FSA into an almost non-toxic metabolite, 10OH-FSA. This mechanism not only neutralized the pathogenicity of Fv but also mediated interspecies interactions contributing to Fv suppression. Additionally, FSA detoxification exhibited broad applicability in controlling different Fusarium diseases in maize, tomato, and wheat. More profoundly, Th-induced FSA detoxification activity in the rhizosphere could stimulate the growth of other FSA detoxification-capable microbes, amplifying disease suppression through ecological cross-talk. These findings unveil an ecological tactic employed by BCAs to manage soil-borne Fusarium wilt disease.

Continuous chemical fertilization is threatening acid soil sustainable use because of soil acidification aggravation and microbial function destruction, whereas organic fertilization has the potential to overcome these shortcomings. However, the mechanisms underlying sustainable crop production under organic fertilization in acid soils are largely unknown. A multi-omics approach provides the opportunity for a comprehensive and deep understanding of how organic fertilization sustains acid soil productivity. We examined maize yield, mineral nutrition, leaf transcriptome and metabolome, rhizosphere microbiome, and soil fertility in a 25-year acid soil field trial including four fertilization treatments: a control without fertilizer, chemical fertilizer, organic fertilizer, and combined chemical and organic fertilizers. This long-term fertilizer trial revealed that applying organic fertilizer sustained high maize yields over 25 years compared with chemical fertilizer. Organic fertilization improved soil fertility and maize mineral nutrition especially phosphorus by enhancing the cooperation between the rhizosphere microbiome and the maize transcriptome and metabolome. Identified microbial keystone taxa, plant functional genes, and metabolites differing between organic and chemical fertilizers were mostly associated with the phosphorus cycle, suggesting that phosphorus is a major contributor to sustained high productivity resulting from organic fertilization. Organic fertilization sustains high maize yields in acid soils through the cooperation of rhizosphere microbes and plants. Phosphorus is the key contributor to acid soil sustainable use under organic fertilization. These findings have important implications for optimizing fertilization regimes in acid soils, ultimately contributing to food security and agricultural sustainability.

IntroductionFusarium-induced root rot of Carya cathayensis (C. cathayensis) is a typical soil-borne disease that has severely damaged the Carya cathayensis industry in China. Understanding the interaction among soil microbial communities, soil characteristics, and pathogenic bacteria is very important for the ecological prevention and control of Carya cathayensis root rot.MethodsWe used Miseq Illumina high-throughput sequencing technology to study the microbial community in the rhizosphere soil of healthy and diseased C. cathayensis, quantified the abundance of bacteria, fungi, and pathogenic fungi, and combined these with soil chemistry and enzyme activity indicators to analyze the characteristics of healthy and diseased rhizosphere soils.ResultsWe found that the pH, soil organic carbon(SOC), available nitrogen (AN), available phosphorus (AP), available potassium (AK),N-acetyl-β-D-glucosaminidase (NAG) β-glucosidase (BG), fungal gene copy number, bacterial community diversity and network complexity of the diseased soil were significantly lower (p < 0.05), while Fusarium graminearum copies number levels increased (p < 0.05). Additionally, the study found that healthy soils were enriched with beneficial bacteria such as Subgroup_7 (0.08%), MND1 (0.29%), SWB02 (0.08%), and Bradyrhizobium (0.09%), as well as potential pathogen-suppressing fungi such as Mortierella (0.13%), Preussia (0.03%), and Humicol (0.37%), were found to be associated with the growth and development of C. cathayensis.DiscussionIn summary, this research comprehensively reveals the differences in environmental and biological factors between healthy and diseased soils, as well as their correlations. It provides a theoretical basis for optimal soil environmental regulation and the construction of healthy microbial communities. This foundation facilitates the development of multifaceted strategies for the prevention and control of C. cathayensis root rot.

The widespread utilization of straw return was a popular practice straw disposal for highly intensive agriculture in China, which has brought about some negative impacts such as less time for straw complete biodegradation, aggravation of greenhouse gas evolution, and lower efficient of carbon accumulation. It was urgent to find an eco-friendly N-rich organic fertilizer instead of mineral N as activator to solve the above problems and lead a carbon accumulation in long tern management. Besides, microbial necromass was considered as a crucial contributor to persistent soil carbon (C) and nitrogen (N) pool. How organic fertilizer activators influence microbial residue under different amount of crop residues input remained unclear. Thus, soils incorporating moderate and high rate of rice straw residue with additions of half and full of organic activators (fish protein hydrolysates vs. manure) were incubated for measuring carbon dioxide (CO2) and nitrous oxide (N2O) emission, microbial community and necromass. It was found that soil CO2 emission was rapidest during the first 13 days of straw decomposition but remained lowest in the treatments of 50% mineral N substituted by fish protein hydrolysate. There were that 81%-89% of total CO2 release and 59%-65% of total N2O emission occurred within 60 days of incubation period, and bacterial community and nitrate positively affected soil CO2 and N2O release respectively. Straw incorporation amount and organic activator application interactively influenced soil CO2 emission but not affected soil N2O emission. After 360 days of incubation, the difference of bacterial necromass was noticeable but fungal necromass remained almost unaltered across all treatments. All treatments showed generally comparable contribution of microbial necromass N to the total N pool. The treatment of 50% mineral N substituted by fish protein hydrolysate under high rate of straw input (HSF50) promoted the highest proportion of microbial necromass C in soil organic C because of alleviating N limitation for microorganisms. Finally, HSF50 was recommended as an eco-friendly strategy for enhancing microbial necromass C and N storage and climate benefits in agroecosystems.

Intensive management is known to markedly alter soil carbon (C) storage and turnover in Moso bamboo forests compared with extensive management. However, the effects of intensive management on soil respiration (RS) components remain unclear. This study aimed to evaluate the changes in different RS components (root, mycorrhizal, and free-living microorganism respiration) in Moso bamboo forests under extensive and intensive management practices. A 1-year in-situ microcosm experiment was conducted to quantify the RS components in Moso bamboo forests under the two management practices using mesh screens of varying sizes. The results showed that the total RS and its components exhibited similar seasonal variability between the two management practices. Compared with extensive management, intensive management significantly increased cumulative respiration from mycorrhizal fungi by 36.73%, while decreased cumulative respiration from free-living soil microorganisms by 8.97%. Moreover, the abundance of arbuscular mycorrhizal fungi (AMF) increased by 43.38%, but bacterial and fungal abundances decreased by 21.65% and 33.30%, respectively, under intensive management. Both management practices significantly changed the bacterial community composition, which could be mainly explained by soil pH and available potassium. Mycorrhizal fungi and intensive management affected the interrelationships between bacterial members. Structural equation modeling indicated that intensive management changed the cumulative RS by elevating AMF abundance and lowering bacterial abundance. We concluded that intensive management reduced the microbial respiration-derived C loss, but increased mycorrhizal respiration-derived C loss.

Both microbes and plants contribute to soil organic carbon (SOC) formation and retention, but their roles in controlling SOC dynamics in forest soils under Moso bamboo ( Phyllostachys edulis ) expansion remain unclear. Here, amino sugars and lignin monomers were measured to represent microbial necromass and plant‐derived components, respectively. The observed decline in both amino sugars and lignin monomers during Moso bamboo expansion indicates a reduction in microbial necromass and recalcitrant plant contributions to SOC composition. This could be attributed to a limitation of microbial substrates and proliferation caused by the reduced litter inputs resulting from the expansion. The proportion of microbial necromass contributing to the SOC pool increased, but that of lignin monomers decreased, as SOC content decreased with Moso bamboo expansion. This suggests that the decrease of SOC during bamboo expansion was mainly due to the reduction of lignin, while the increased contribution of microbial‐derived carbon to SOC may serve to improve SOC stability. Our study sheds light on the altered SOC source inputs resulting from Moso bamboo expansion and emphasizes the need for sustainable forestry management practices that differentiate between microbial‐ and plant‐derived carbon pools.

亚热带毛竹扩张对杉木林土壤微生物残体碳积累的影响及机制尚不清楚.以毛竹向杉木林扩张带(包括杉木林、杉木-毛竹混交林和毛竹林)的凋落物(O层)和不同发生层土壤(A层、B层和BC层)为研究对象,通过分析凋落物和土壤样品中的氨基糖含量来表征微生物残体碳累积效应,并进一步评价微生物在土壤有机碳(SOC)形成过程中的作用.结果表明:毛竹扩张使杉木林凋落物数量和碳含量显著降低,但是凋落物中真菌残体碳(MRC-f)、细菌残体碳(MRC-b)和微生物残体碳(MRC)含量均显著增加;毛竹扩张显著提高了杉木林SOC、MRC-f、MRC-b和MRC含量,而且在毛竹扩张初期(杉木林演替为杉木-毛竹混交林)MRC-f、MRC-b和MRC在SOC中的比例也显著增加,说明毛竹扩张增强杉木林土壤MRC累积效应的同时,也提高了微生物对有机碳的贡献.而毛竹扩张后期MRC-f、MRC-b和MRC占SOC比例并没有显著变化,意味着毛竹扩张后期MRC和植物源残体碳对SOC含量的提升均有贡献,且两者贡献的相对比例保持不变.土壤MRC含量随着剖面深度的加深逐渐下降,而MRC占SOC比值却随着土壤深度的增加而逐渐升高,说明深层土壤中微生物对有机碳贡献高于表层土壤.研究结果对于理解微生物在亚热带森林SOC形成过程中的作用,科学评估毛竹扩张对亚热带森林生态系统及气候变化的影响,并采取合理的营林措施提升亚热带森林土壤碳汇功能具有重要理论意义.

Rhizome rot is one of the main disease in the cultivation of Polygonatum cyrtonema, and it is also a global disease which seriously occurs on the perennial medicinal plants such as Panax notoginseng and P. ginseng. There is no effective control method at present. To identify the effects of three biocontrol microbes(Penicillium oxalicum QZ8, Trichoderma asperellum QZ2, and Brevibacillus amyloliquefaciens WK1) on the pathogens causing rhizome rot of P. cyrtonema, this study verified six suspected pathogens for their pathogenicity on P. cyrtonema. The result showed that Fusarium sp. HJ4, Colletotrichum sp. HJ4-1, and Phomopsis sp. HJ15 were the pathogens of rhizome rot of P. cyrtonema, and it was found for the first time that Phomopsis sp. could cause rhizome rot P. cyrtonema. Furthermore, the inhibitory effects of biocontrol microbes and their secondary metabolites on three pathogens were determined by confrontation culture. The results showed that the three tested biocontrol microbes significantly inhibited the growth of three pathogens. Moreover, the secondary metabolites of T. asperellum QZ2 and B. amyloliquefaciens WK1 showed significant inhibition against the three pathogens(P<0.05), and the effect of B. amyloliquefaciens WK1 sterile filtrate was significantly higher than that of high tempe-rature sterilized filtrate(P<0.05). B. amyloliquefaciens WK1 produced antibacterial metabolites to inhibit the growth of pathogens, and the growth inhibition rate of its sterile filtrate against three pathogens ranged from 87.84% to 93.14%. T. asperellum QZ2 inhibited the growth of pathogens through competition and antagonism, and P. oxalicum QZ8 exerted the inhibitory effect through competition. The research provides new ideas for the prevention and treatment of rhizome rot of P. cyrtonema and provides a basis for the di-sease control in other crops.

Moso bamboo (Phyllostachys Pubescens) expansion into adjacent forests has been widely reported to affect plant diversity and its association with mycorrhizal fungi in subtropical China, which will likely have significant impacts on soil respiration. However, there is still limited information on how Moso bamboo expansion changes soil respiration components and their linkage with microbial community composition and activity. Based on a mesh exclusion method, soil respirations derived from roots, arbuscular mycorrhizal (AM) mycelium, and free-living microbes were investigated in a pure Moso bamboo forest (expanded), an adjacent broadleaved forest (non-expanded), and a mixed bamboo-broadleaved forest (expanding). Our results showed that bamboo expansion decreased the cumulative CO2 effluxes from total soil respiration, root respiration and soil heterotrophic respiration (by 19.01%, 30.34%, and 29.92% on average), whereas increased those from AM mycelium (by 78.67% in comparison with the broadleaved forests). Bamboo expansion significantly decreased soil organic carbon (C) content, bacterial and fungal abundances, and enzyme activities involved in C, N and P cycling whereas enhanced the interactive relationships among bacterial communities. In contrast, the ingrowth of AM mycelium increased the activities of β-glucosidase and N-acetyl-β-glucosaminidase and decreased the interactive relationships among bacterial communities. Changes in soil heterotrophic respiration and AM mycelium respiration had positive correlations with soil enzyme activities and fungal abundances. In summary, our findings suggest that bamboo expansion decreased soil heterotrophic respiration by decreasing soil microbial activity but increased the contribution of AM mycelial respiration to soil C efflux, which may potentially increase soil C loss from AM mycelial pathway.

Moso bamboo (Phyllostachys edulis) invasion into adjacent broadleaf forests has been widely observed across subtropical China, and has induced negative effects on aboveground biodiversity. However, how bamboo invasion influences soil microbial community structure and assembly process remains largely unknown. We investigated the changes in diversity, structure and assembly processes of bacterial and fungal communities in an evergreen broadleaf forest following Moso bamboo invasion. Soil samples were collected from three forests (a pure Moso bamboo forest, an adjacent mixed bamboo-broadleaf forest, and a non-invaded broadleaf forest) along twelve invasion transects. Our results showed that bamboo invasion increased soil pH and decreased the contents of soil organic carbon (SOC), dissolved organic carbon (DOC), total and available nitrogen and phosphorus nutrients. Bamboo invasion significantly increased the diversity indices (i.e., OTU richness and Shannon index) of both bacteria and fungi and changed their community compositions (P < 0.05). Bamboo invasion significantly decreased the relative abundance of Actinobacteria and Basidiomycota whereas increased those of Ascomycota and Mortierellomycota. The co-occurrence network analysis displayed more connected and complex relationships of both bacterial and fungal communities in bamboo forest. Bamboo invasion increased the community-level habitat niche breadths of both bacterial and fungal communities due to increased abundances of generalists. The stochastic process of bacterial and fungal community assembly weakened and the deterministic process enhanced generally as a result of bamboo invasion. The migration rate of bacterial communities (0.615) was higher than that of fungal communities (0.037), indicating that dispersal limitation less affect bacteria taxa. Random forest model demonstrated that DOC content, followed by mineral N, were the most important factors mediating the bacterial and fungal community assembly. Taken together, our results suggest that bamboo invasion strongly altered the assembly of bacterial and fungal communities by regulating the deterministic-stochastic balance, which deepens our understanding of the role of bamboo invasions on ecological processes.

[目的]连作障碍给农业生产造成巨大的经济损失,而不同植物耐受连作障碍能力存在差异,特别是禾本科Poaceae植物很少有连作障碍的研究报道.为此,从植物角度出发,分析不同植物(科)连作3季后7种土壤酶活性的变化规律,旨在探究不同植物耐连作障碍的机制.[方法]分别选择豆科Fabaceae、葫芦科Cucurbitaceae、茄科Solanaceae每科各2种以及5种禾本科植物模拟连作的盆栽试验,分别采集第1季和第3季植物收获后的根区土壤,分析土壤pH,有效氮、磷,碳、氮、磷循环相关酶活性.[结果]不同植物3季连作后土壤pH呈下降趋势,第1季和第3季玉米Zea mays pH始终最高,而西瓜Citrullus lanatus最低.土壤有效氮、磷质量分数明显增加,大部分植物土壤第3季时有效氮、磷质量分数均在500 mg·kg?1以上.第1季植物土壤酶活性没有呈现差异规律,第3季非禾本科植物土壤α-葡萄糖苷酶(AG)高于禾本植物,而纤维二糖水解酶(CB)正好相反.不同科植物之间、甚至同科的2种植物之间土壤酶变化规律并不一致.比较明确的规律是:第1季和第3季,黍亚科Panicinae植物(玉米和高粱Sorghum bicolor)土壤酸性磷酸酶(PHOS)活性均最高,第3季禾本科植物土壤β-木糖苷酶(XYL)活性显著高于(P<0.05)非禾本科植物,而早熟禾亚科Pooideae植物(二穗短柄草Brachypodium distachyon、小麦Triticum aestivum、黑麦草Lolium perenne)土壤又普遍高于黍亚科植物.土壤酶总体呈动态增加趋势,其中CB、PHOS和亮氨酸氨基肽酶(LAP)活性分别为早熟禾亚科、葫芦科和黍亚科增幅最大;同属禾本科的黍亚科和早熟禾亚科植物土壤PHOS活性分别呈下降和上升的相反趋势.[结论]禾本科植物土壤PHOS和XYL活性较高,其他酶活性并没有表现出明显的同科变化规律.

"双万计划"实施背景下,浙江农林大学"土壤学"课程积极面对课程内容结构与经济社会发展需求的联系不够紧密、课程内容更新滞后于土壤学学科的发展、课程教学方式与学生的期待存在差距等挑战,围绕"教学团队与科研团队一体化建设、科学研究与教学资源一体化建设、一流课程与制度保障一体化建设",加强新时代背景下的课程内涵建设,在明确"建设一流的教学团队、优化课程教学内容体系、建立科学的教学管理制度"等课程建设与改革目标的基础上,对课程升级提质路径进行了探索.首先,从组织、目标、考核一体化入手,开展教学团队与科研团队一体化建设.其次,通过将最新研究成果编入教材、将科研成果或项目与实验项 目相结合并引入实践基地、以科研项 目支持本科生创新等,开展科学研究与教学资源一体化建设.最后,通过出台教学团队与科研团队一体化建设的管理制度、科学研究与教学资源一体化建设的激励制度、鼓励教师积极投入教学的奖励制度等,开展一流课程与制度保障一体化建设.经过实践探索,"土壤学"课程建设与改革取得了明显成效:及时更新了课程教学内容,丰富了课程实践教学内容和形式,提升了学生的科研创新能力;特别是创新了"土壤学"课程升级提质的路径,优化了课程推陈致新的立体多维模式,建立了教学与科研一体化的良性循环机制.

[目的]探讨毛竹林长期有机无机肥配施对土壤固碳和固氮微生物群落结构的影响,以期为我国竹林土壤肥力维持和提高提供理论依据.[方法]采集毛竹林集约经营6年(IM6)、10年(IM10)、15年(IM15)、20年(IM20)的表层(0～20 cm)和亚表层(20～40 cm)土壤,以立地条件相同且未施肥毛竹林为对照(CK),采用荧光定量PCR(qPCR)、末端限制性片段长度多态分析(T-RFLP)和克隆文库,进行冗余分析(RDA).[结果]1)不同经营年限土壤pH值稳定在5.0～5.5,土壤有机碳(SOC)、全氮(TN)、碱解氮(AN)和速效钾(AP)含量波动较大,但与CK相比,经营20后土壤养分含量均显著上升(P<0.05).2)与CK相比,表层土壤固碳基因cbbL丰度在IM6时显著降低(P<0.05),IM20时土壤cbbL基因丰度恢复至CK水平;而各经营年限的土壤固氮基因nifH丰度显著低于CK(P<0.05)并持续下降.固碳和固氮微生物Shannon指数和均匀度指数在IM10显著下降(P<0.05),IM20时显著提高(P<0.05).毛竹林各经营年限固碳微生物群落结构与CK差异显著,而固氮微生物的IM20群落结构与CK相似.3)系统发育分析表明,固碳微生物的优势菌群主要是变形菌门的慢生根瘤菌、百分红螺菌、运动硫黄球菌、美叶葡萄球菌、菊苣中根瘤菌、Starkeya novella;固氮微生物优势菌群主要是根瘤菌.4)固碳微生物群落结构与土壤AP和NH4+-N含量以及 δ13 C变化显著相关,固氮微生物群落结构与土壤AP、AK、SOC、NO3--N、C:N和AN变化显著相关(P<0.05).[结论]毛竹林长期配施有机无机肥,提高了土壤养分含量,且未造成土壤酸化,对改善土壤养分具有积极作用,土壤养分变化是驱动毛竹林土壤中固碳和固氮微生物丰度、多样性和群落结构变化的重要原因.

Soil extracellular enzyme activities among aggregate fractions are critical to short-term microbial activity and long–term carbon dynamics in forest ecosystems, but little is known regarding the effects of forest types on the soil enzyme activities in different soil aggregate fractions. Three typical subtropical forest types (Broadleaved forest, Moso bamboo forest and Chinese fir forest) were selected, and undisturbed soil samples (0–15 cm) were collected. We investigated the effects of forest types on aggregate stability (mean weight diameter, geometric mean diameter and fractal dimension), aggregate–associated organic carbon (OC) and the functionality of five enzymes (cellobiohydrolase, β-glucosidase, β-xylosidase, N–acetylglucosaminidase, leucine aminopeptidase) of different aggregate fractions (>2 mm, 0.25–2 mm, 0.053–0.25 mm and <0.053 mm). The results showed that the proportion of macro-aggregates, aggregate stability and macro–aggregates associated–carbon content and storage were higher in broadleaved and Moso bamboo forests than in Chinese fir forests, indicating that forest types influence the distribution of total soil OC among aggregate fraction classes and would delay the loss of OC in broadleaved and Moso bamboo forests. We also found that the extracellular enzymes were higher in aggregates of broadleaved forests and Moso bamboo forests. SEM (structural equation model) analysis also supported significantly positive relationships between litter quantity and aggregate enzyme activity, and indirect impact of litter quantity and litter C/N ratio together with soil organic carbon (SOC) and soil aggregate organic C content (SAOCC) on aggregate enzyme activity. The results of this study indicate that forest types showed large impact on aggregate-associated OC and enzyme activities, and the litter input of different forest types is the main control on enzyme activity among different aggregate fractions, and thus may play an important role in adjusting the sink capacity and stability of SOC.

The special eco-physiological characteristics of moso bamboo (Phyllostachys edulis) facilitate their fast invasion in nature ecosystems. The widespread expansion of moso bamboo causes degradation of adjacent forest ecosystem and change of landscape, as well as soil properties and microbial community composition. However, how moso bamboo expansion affects soil microbial composition is far from fully understood. Herein, we selected four moso bamboo expansion transects with three forest types at the Anji Lingfeng temple forest farm, Zhejiang Province, including evergreen broadleaved forest (BLF), mixed P. edulis and broadleaved forest (MEF) and P. edulis forest (PEF). We examined the effects of moso bamboo expansion on soil properties and soil microbial phospholipid fatty acids (PLFAs). Our results showed that soil pH was higher in moso bamboo forest than in MEF and BLF by 0.37 and 0.32 unit. In contrast, soil organic carbon, ammonium, and nitrate contents significantly decreased. Biomass of soil microbial groups displayed a decreasing trend except arbuscular mycorrhizal fungi, and the microbial richness index (SR) and diversity index (H) decreased significantly. In summary, moso bamboo expansion affected soil nutrient and carbon inputs, which was an important factor affecting soil microbial community structure. Results of redundancy analysis showed that changes of soil organic carbon and ammonium content were the main factors driving soil microbial community.