坝上地区实施退耕还林还草面临的问题与对策

阐述了河北省坝上地区实施退耕还林还草面临的问题，指出实施退耕还林还草工程的关键是区域产业结构调整与农民经济利益提高相结合，合理界定退耕还林还草地或标准、条件、规模、植被恢复标准与指标体系，研究与组装不同退化生态系统类型的退耕还林还草模式，通过实施效果（生态、经济）监测和评价筛选出切实可行的推广模式，并建立起符合市场经济体制要求的土地产权制度、利益分配机制和组织经营形式以及部门间协调统一，并提出发展对策。     

南方红壤丘陵区退耕还林还草工程土壤保持效应评估

以南方红壤丘陵区为研究对象，应用修正通用土壤流失方程，根据2000年、2005年、2010年、2015年土地利用数据，识别出了近15年南方红壤丘陵区退耕还林还草的空间范围，并估算了退耕还林还草实际发生区的土壤保持效应。结果表明，2000—2015年，南方红壤丘陵区退耕还林还草面积约2 052.61 km²。期间土壤保持量增加9.18×10⁸ t，单位面积土壤保持量变化量为447 327.54 t/km²，土壤保持效应整体显著提升，但仍有部分区域出现负效益。此外，对提升土壤保持功能而言，将裸地转换为林地是效果最显著的土地利用变化方式。退耕还林还草的实施提高了区域的土壤保持功能。研究结果对南方红壤丘陵区退耕还林还草工程的实施及管理具有指导意义。     

黄土丘陵区退耕地土壤水分有效性及蓄水性能--以陕西省吴旗县柴沟流域为例

对退耕还林还草区具有代表性的乔木(山杏和刺槐)、灌木、农田的土壤水分有效性和蓄水能力进行了测定和对比研究。结果表明,不同植被类型的土壤有效水含量变化范围为1.92%~15.73%,林地比农田增加约75.31%。0—40 cm土层土壤蓄水量为228.30~251.07 t/hm2,林地比农田增加约8%。刺槐林地的蓄水性能好于山杏。研究成果对于科学地评价退耕还林还草的土壤改良效应具有重要的意义。     

内蒙古中部地区退耕还林还草后植被与土壤性状的变化

北方农牧交错带中部的内蒙古乌盟一带退耕还林还草有10余年的历史.通过野外调查和实验室分析,探讨了不同退耕还林还草模式和年限下植物群落和土壤性质的变化,结果表明:(1)人为控制了苜蓿、沙打旺的种植周期的退耕还草工程使得退耕还草后植物群落完全不同于自然群落的演替过程,退耕年限达到6年后严重退化指示植物才大量消失;(2)退耕还林与退耕还草均起到了阻沙作用.但退耕还草在降低土壤砂含量方面效果相对明显;(3)退耕还林还草所带来的植物物种多样性变化与土壤性状变化存在正相关关系,说明土壤性状的改良与物种多样性的增加可能     

陕西吴起县退耕还林地不同植被水土保持效益分析

在全国退耕还林工程示范县陕西省吴起县退耕还林地内设置了野外径流小区,在对其进行了土壤物理性质、入渗、抗冲实验及实测泥沙资料基础上,分析了退耕还林后不同植被类型的水土保持效益,结果显示:土壤入渗的初渗率、稳渗率、平均入渗率大小顺序为油松荒草地沙棘+油松b沙棘+油松a沙棘;土壤抗冲性能沙棘林地最强,沙棘+油松林地次之,油松林地最弱;土壤产沙量为油松林地最大,沙棘与沙棘+油松林地相对较少;地表径流量为油松林地荒草地沙棘+油松林地b沙棘+油松林地a沙棘林地;退耕还林后,土壤物理性质得到不同的改良。油松林地的土壤容重最高,土壤总孔隙度与土壤毛管孔隙度最低。因此,退耕还林可有效地防治水土流失,而不同植被类型中沙棘纯林的水土保持效益最为显著。     

农牧交错区退耕还林地土壤恢复特征的研究——以内蒙古卓资县为例

以卓资县退耕还林地为研究对象,探讨不同退耕还林地土壤理化性质的变化规律及改良作用。初步研究结果表明:退耕还林以后土壤黏粒总体含量均高于耕地,其中表土层增加不显著,亚表层、下层增加较多;在不同的退耕还林地中,表层土壤容重明显高于亚表层和下层的土壤容重;不同退耕还林模式下土壤有机质含量均随土层深度增加而递减,表现出明显的表聚性;不同林地类型之间的全量N、P、K的含量变化差异显著,而不同土层深度的全量P、K的差异不显著;不同退耕林地的速效N、P、K的含量变化幅度较大。总体来看当地实施退耕还林后,对土壤的改良效果明显,有效的改善了当地生态环境。     

不同退耕年限林草地土壤颗粒分形特征研究

选用不同退耕年限林地、草地各3块,对0—60cm土壤进行土壤机械组成及分形维数研究,分析土壤颗粒特征与土壤基本性质之间的相关关系。结果表明:随着退耕年限的增加,土壤粘粒含量与颗粒分形维数有增长趋势,林地较草地变化显著;林、草地中土壤颗粒分形维数随土层加深均降低,林地较草地降低明显;随着年限的增加,土壤基本性质得到改善,饱和含水率、总孔隙度、水稳性团聚体及有机质尤为显著;土壤颗粒分形维数与水稳性团聚体、饱和含水率、总孔隙度、有机质和粘粒含量均存在显著正相关关系。退耕还林还草可改善土壤基本性质,土壤质地有向粘性发展的趋势,土壤分形维数提高,其中以林地最为显著。     

基于土地适宜性评估退耕还林还草工程的效果——以科尔沁左翼后旗吉尔嘎朗镇为例

选取科尔沁沙地典型区域为研究对象,运用遥感数据和GIS空间信息技术,基于土地的自然适宜性,对2000─2007年研究区退耕还林还草工程实施情况做出评价,并指出今后退耕任务和需要注意的问题。研究发现:退耕还林还草工程实施以来,吉尔嘎朗镇耕地明显减少,林地、草地明显增加,草地覆盖度显著提高;从7年间实际退耕还林还草方向、数量和空间分布来看,存在许多不合理的地方,主要是还林还草选择不合理,不宜耕作的土地还有很多没有退耕,实际退耕土地只占应退耕土地的28.63%;还有8 172.00 hm2土地应当逐步实现退耕,其中以退耕还林为主,占73.29%。政策方面,建议发展地区优势产业,积极推动农村富余劳动力转移就业,一方面增加农牧民家庭收入,另一方面减小人口对土地的压力,保证生态退耕工程持续见效。     

退耕生态系统碳储量时空动态变化的研究进展

退耕还林还草作为土地利用方式改变的重要形式之一,对退耕生态系统碳储量产生深远影响。从时间、空间以及退耕还林还草模式等方面综述了退耕还林还草对植被碳库和土壤碳库产生的影响,同时探讨了枯落物和根系周转对土壤碳库动态的效应。现有研究表明,退耕生态系统碳储量对退耕时间、空间和模式有不同程度的响应。最后,提出了退耕生态系统碳储量时空动态研究需解决的关键问题。     

张家口市的防沙治沙

张家口市是北京地区沙尘灾害的主要沙源之一 ,水土流失和土地沙化极为严重。官厅水库上游永定河流域 18年国家水土保持重点防治工程的实施 ,积累了适合本地治理侵蚀、防治风沙的经验。坝上地区应在建设高标准基本农田的基础上实行退耕还林还草 ,坝下地区的防沙治沙应实行工程措施与植物措施相结合 ,防沙治沙应合理开发利用水资源 ,实行节水灌溉。     

Fire severity shapes plant colonization effects on bacterial community structure,microbial biomass,and soil enzyme activity in secondary succession of a burned forest

The increasing frequency and severity of wildfires has led to growing attention to the effects of fire disturbance on soil microbial communities and biogeochemical cycling. While many studies have examined fire impacts on plant communities, and a growing body of research is detailing the effects of fire on soil microbial communities, little attention has been paid to the interaction between plant recolonization and shifts in soil properties and microbial community structure and function. In this study, we examined the effect of a common post-fire colonizer plant species, Corydalis aurea, on soil chemistry, microbial biomass, soil enzyme activity and bacterial community structure one year after a major forest wildfire in Colorado, USA, in severely burned and lightly burned soils. Consistent with past research, we find significant differences in soil edaphic and biotic properties between severe and light burn soils. Further, our work suggests an important interaction between fire severity and plant effects by demonstrating that the recolonization of soils by C. aurea plants only has a significant effect on soil bacterial communities and biogeochemistry in severely burned soils, resulting in increases in percent nitrogen, extractable organic carbon, microbial biomass, β-glucosidase enzyme activity and shifts in bacterial community diversity. This work propounds the important role of plant colonization in succession by demonstrating a clear connection between plant colonization and bacterial community structure as well as the cycling of carbon in a post-fire landscape. This study conveys how the strength of plant–microbe interactions in secondary succession may shift based on an abiotic context, where plant effects are accentuated in harsher abiotic conditions of severe burn soils, with implications for bacterial community structure and enzyme activity.     

长期不同施肥措施下塿土细菌群落结构变化及其主要影响因素

? 【目的】 ?研究不同施肥处理下土壤细菌群落的特征，为建立促进土壤生态系统稳定和健康的养分管理制度提供依据。? 【方法】 ?陕西省杨凌示范区“国家黄土肥力与肥料效益监测基地”的28年长期定位试验始于1990年秋，种植制度为冬小麦–夏休闲，无灌溉。本研究选取定位试验中不施肥 (CK)、施用氮磷钾肥 (N、P₂O₅、K₂O分别为135、108、67.5 kg/hm2，NPK) 和有机无机肥配施 (70% N来自牛粪，MNPK) 3个处理。于2018年6月小麦收获后采集0—20 cm耕层土样，测定养分含量、含水量、微生物量碳含量、微生物量氮含量及目标土壤微生物。以1%琼脂糖凝胶电泳法检测土壤中DNA，根据97%相似度对序列进行OTU聚类、α多样性分析 (包括Shannon、ACE和Chao1等指数)，使用CANOCO 4.5软件对土壤细菌门水平群落结构、细菌相对丰度等与土壤理化性质进行冗余分析。? 【结果】 ?与CK相比，NPK和MNPK处理显著提高了土壤有机碳、全氮、微生物量碳、微生物量氮、硝态氮和铵态氮含量，显著降低了土壤pH值。不同处理细菌基因拷贝数为每克干土6.69 × 109～16.46 × 109，与CK相比，NPK和MNPK处理细菌数量分别提高了77%和146%。MNPK处理的土壤细菌Shannon多样性指数显著高于CK和NPK处理，而Simpson指数显著低于CK和NPK处理，NPK与CK处理间两个指数无显著差异。3个处理的细菌丰富度指数 (Chao1指数和ACE指数) 和均匀度指数均没有显著差异。在门水平上，共获得35个细菌类群，其中，放线菌门 (Actinobacteria)、变形菌门 (Proteobacteria)、酸杆菌门 (Acidobacteria) 和绿弯菌门 (Chloroflexi) 为主要优势菌门 (相对丰度 > 10%)，占到全部菌门的80.1%～81.7%。与CK相比，MNPK处理显著降低了放线菌门 (F = 5.845，P < 0.05) 的相对丰度，增加了拟杆菌门 (F = 4.461，P < 0.05) 的相对丰度，3个处理间其他菌门均无显著差异。冗余分析结果显示，CK与NPK、MNPK处理的土壤细菌群落结构具有明显差异，且MNPK处理对土壤细菌群落组成的影响更大。土壤理化性质对细菌菌群影响表现为:土壤硝态氮 > 可溶性有机碳 > pH > 铵态氮 > 有机碳 > 土壤含水量，这些理化因子均是影响微生物生长的关键因子。? 【结论】 ?关中土区旱作雨养条件下，化肥平衡施用和有机无机肥配施均显著提高了土壤中细菌数量、多样性和丰富度，有机无机肥配施还改变了细菌群落结构，特别是降低了放线菌门、增加了拟杆菌门的丰度，更有利于土壤生态系统的稳定和健康。     

Does microbial habitat or community structure drive the functional stability of microbes to stresses following re-vegetation of a severely degraded soil?

Re-vegetation of eroded soil restores organic carbon concentrations and improves the physical stability of the soil, which may then extend the range of microhabitats and influence soil microbial activity and functional stability through its effects on soil bacterial community structure. The objectives of this study were (i) to evaluate the restorative effect of re-vegetation on soil physical stability, microbial activity and bacterial community structure; (ii) to examine the effects of soil physical microhabitats on bacterial community structure and diversity and on soil microbial functional stability. Soil samples were collected from an 18-year-old eroded bare soil restored with either Cinnamomum camphora (“Eroded Cc”) or Lespedeza bicolour (“Eroded Lb”). An uneroded soil planted with Pinus massoniana (“Uneroded Pm”) and an eroded bare soil served as references. The effect of microhabitats was assessed by physical destruction with a wet shaking treatment. Soil bacterial community structure and diversity were measured using a terminal restriction fragment length polymorphism (T-RFLP) approach, while soil microbiological stability (resistance and resilience) was determined by measuring short-term (28 days) decomposition rate of added barley (Hordeum vulgare) powder following copper and heat perturbations. The results demonstrated that re-vegetation treatment affected the recovery of physical and biological stability, microbial decomposition and the bacterial community structure. Although the restored soils overshot the Uneroded Pm sample in physical stability, they had lower microbial decomposition and less resilience to copper and heat perturbations than the Uneroded Pm samples. Soil physical destruction by shaking had the same effect on soil physical stability, but different effects on soil microbial functional stability. There were significant effects of vegetation treatment and perturbation type, and interactive effects among vegetation treatment, shaking and perturbation type on bacterial community structure. The destruction of aggregate structure increased resilience of the Eroded Lb sample and also altered its bacterial community structure. Both copper and heat perturbations resulted in significantly different community structure from the unperturbed controls, with a larger effect of copper than heat perturbation. Bacterial diversity (Shannon index) increased following the perturbations, with a more profound effect in the Uneroded Pm sample than in the restored soils. The interactive effects of vegetation treatment and shaking on microbial community and stability suggest that soil aggregation may contribute to the generation of bacterial community structure and mediation of biological stability via the protection afforded by soil organic carbon. Differential effects of re-vegetation treatment suggest that the long-term effects are mediated through changes in the quality and quantity of C inputs to soil.     

甘蔗宿根矮化病感病与非感病株根际土壤生物学性状及细菌群落结构特征

[目的]比较甘蔗宿根矮化病(ratoon stunting disease,RSD)感病植株与非感病植株根际土壤的生物学性状及细菌群落结构特征,旨在为构建甘蔗健康的根际微环境,筛选高效RSD生防细菌提供参考。[方法]通过田间调查和实验室鉴定,以甘蔗RSD感病植株为试材,非感病植株为对照,采集甘蔗RSD感病植株和非感病植株的根际土壤,并基于传统和现代高通量测序技术,分析了甘蔗RSD感病植株和非感病植株根际土壤的生物学性状和细菌群落结构特征。[结果]与甘蔗RSD非感病植株相比,感病植株根际土壤中指示土壤肥力与健康状况的生物学性状指标β-葡糖苷酶、磷酸酶和氨肽酶活性,以及微生物生物量碳、氮、磷显著降低;同时,指示细菌丰富度的Chao1指数和指示细菌多样性的Shannon指数显著下降。门分类水平与非感病甘蔗植株相比,RSD感病植株根际土壤中Proteobacteria(变形杆菌门)、Actinobacteria(放线菌门)、Gemmatimonadetes(芽单胞菌门)和Nitrospirae(硝化螺旋菌门)等优势门类细菌占比呈倍级降低,但Chloroflexi(绿弯菌门)、Acidobacteria(酸杆菌门)、Firmicutes(厚壁菌门)、Cyanobacteria(蓝细菌门)、Planctomycetes(浮霉菌门)、Bacteroidetes(拟杆菌门)等优势门类细菌占比呈倍级增加;在属分类水平,与非感病甘蔗植株相比,RSD感病植株根际土壤中Xanthobacteraceae(黄色杆菌属)、Acidothermus、Gaiellales、Roseiflexus(玫瑰菌属)、Micromonosporaceae(小单孢菌属)和Nitrospira(硝化螺旋菌属)细菌占比呈倍级降低,但Acidobacteria(嗜酸菌属)细菌及部分未知菌属却呈倍级提高。[结论]甘蔗RSD感病植株根际微环境中指示土壤肥力的生物学指标显著降低,细菌丰富度和多样性显著下降,部分优势细菌门属占比发生剧变可能是导致甘蔗RSD发生的重要原因。     

喀斯特生态系统中乔木和灌木林根际土壤微生物生物量及其多样性的比较

我国喀斯特区域面积分布较广,而喀斯特生态系统的退化已成为当前西南地区面临的严重的生态问题。本研究选取贵州中部两种不同植被类型的生态系统—乔木林和灌木林,以乔木林中的白栎、园果化香和灌木林中的火棘、竹叶椒等主要优势树种为对象,研究不同的植物树种对根际土壤微生物生物量及其细菌群落结构的影响。结果显示:乔木林系统中根际土壤微生物生物量碳、氮显著性高于灌木林,植物的根际效应在乔木林中表现更为显著;同时乔木林中的优势树种通过根系分泌物的作用显著提高根际土壤细菌多样性指数,而灌木林中优势树种的根际土壤微生物量及多样性均未表现出明显的根际效应。因此,植被的演替通过改变土壤微生物的特性影响植物-微生物-土壤之间的物质和能量循环,进一步影响喀斯特生态系统的稳定和健康功能。     

Long-term effect of plastic film mulching and fertilization on bacterial communities in a brown soil revealed by high through-put sequencing

The objective of this study was to access the effect of long-term fertilization and film mulching application on soil properties and bacterial community structure. We used 16S rRNA gene to investigate soil bacterial community composition by high through-put sequencing. The results demonstrated that predominant groups in the bacterial community were: Proteobacteria, Bacteroidetes, Actinobacteria, Acidobacteria, Firmicutes, Planctomycetes, Gemmatimonadetes, Verrucomicrobia, Chloroflexi and Cyanobacteria. Long-term fertilization of combined manure and nitrogen application caused significant decrease in soil bacterial diversity and richness compared to non-fertilization control, though manure fertilization alone played a significant role in restoring bacterial diversity. Film mulching and manure fertilization significantly increased the relative abundances of soil bacterial groups mentioned above. Furthermore, film mulching played significant role in shaping the bacterial community structure regardless of fertilization. Redundancy analysis (RDA) showed that soil moisture content, pH, total N and soil organic C had significant (P < 0.05) influence on dominant bacterial groups. Altogether, plastic film mulching and manure application prevented loss of soil bacterial diversity and abundance during long-term fertilization. These findings showed the detrimental use of combined manure and nitrogen fertilization to soil microbes and the useful application of manure fertilization coupled with film mulching to soil biodiversity in long-term fertilization experiments.     

不同植物秸秆腐解特性与土壤微生物功能多样性研究

采用网袋法探讨不同秸秆在3个长期试验地的腐解特征,结合Biolog微平板技术,对不同长期试验地土壤微生物群落多样性进行了研究。结果表明,随着腐解时间的增加,秸秆腐解的变化趋势为烘干秸秆新鲜秸秆。葡萄园土壤微生物活性高,稳定性好,其次为桃园和农田。农田土壤微生物活性低、稳定性差,不同处理的秸秆在腐解过程中残留率变化较大,而果园土壤微生物活性相对较高、稳定性好,不同处理的秸秆在腐解过程中残留率变化较小。土壤碱解氮、速效磷和土壤温度与土壤微生物群落的三大指数呈极显著相关,且不同秸秆处理的腐解残留率与土壤微生物群落的优势度呈显著负相关,微生物群落在一定程度上影响了秸秆分解的速率。     

不同恢复方式下盐渍化弃耕地土壤生物学活性的变化

以干旱区新疆玛纳斯河流域冲积扇缘定点定位试验地为研究对象, 研究灌溉处理、人工草地处理和补植处理对盐渍化弃耕地土壤微生物量、酶活性及土壤呼吸速率的影响。结果表明, 不同恢复方式均明显增加了土壤微生物数量和土壤微生物量碳、氮及土壤酶活性。不同处理土壤微生物量碳、氮分别比原始弃耕地高17.80%、26.38%、5.33%和7.89%、12.75%、21.93%; 不同处理土壤微生物数量分别是原始弃耕地的4.72倍、6.04倍和4.56倍; 不同处理土壤蔗糖酶活性分别比原始弃耕地高3.4倍、3.2倍和7.7倍, 多酚氧化酶活性比原始弃耕地高1.7倍、1.2倍和1.5倍, 脲酶活性比原始弃耕地高11.1%、52.3%和37.1%; 灌溉处理土壤过氧化氢酶活性最高, 是原始弃耕地的1.53倍, 土壤呼吸速率变化表现为人工草地处理>灌溉处理>补植处理>原始弃耕地, 其中, 人工草地处理土壤呼吸速率比弃耕地高52.25%。相关分析表明, 微生物量碳与微生物C/N和微生物数量之间均呈显著正相关关系(P<0.05); 土壤呼吸速率与土壤脲酶、微生物数量和微生物量碳的相关性达到显著水平(P<0.05), 与土壤微生物量氮呈负相关关系, 但相关性不显著; 土壤蔗糖酶与其他3种酶以及微生物量氮呈显著正相关关系, 土壤脲酶与微生物数量呈显著正相关关系, 多酚氧化酶与过氧化氢酶相关性达到显著水平(P<0.05)。本研究表明干旱区盐渍化弃耕地采用灌溉与人工草地处理有利于土壤养分积累, 可在一定程度上改善土壤质量。     

Microbial community PLFA and PHB responses to ecosystem restoration in tallgrass prairie soils

Native North American prairie grasslands are renowned for the richness of their soils, having excellent soil structure and very high organic content and microbial biomass. In this study, surface soils from three prairie restorations of varying ages and plant community compositions were compared with a nearby undisturbed native prairie remnant and a cropped agricultural field in terms of soil physical, chemical and microbial properties. Soil moisture, organic matter, total carbon, total nitrogen, total sulfur, C:N, water-holding capacity and microbial biomass (total PLFA) were significantly greater (p<0.05) in the virgin prairie remnant as well as the two long-term (21 and 24 year) prairie restorations, compared with the agricultural field and the restoration that was begun more recently (7 years prior to sampling). Soil bulk density was significantly greater (p<0.05) in the agricultural and recently restored sites. In most cases, the soil quality indicators and microbial community structures in the restoration sites were intermediate between those of the virgin prairie and the agricultural sites. Levels of poly-β-hydroxybutyrate (PHB) and PLFA indicators of nutritional stress were significantly greater (p<0.05) in the agricultural and recent restoration sites than in the long-term restorations or the native prairie. Samples could be assigned to the correct site by discriminant analysis of the PLFA data, with the exception that the two long-term restoration sites overlapped. Redundancy analysis showed that prairie age (p<0.005) was the most important environmental factor in determining the PLFA microbial community composition, with C:N (p<0.015) also being significant. These findings demonstrate that prairie restorations can lead to improved quality of surface soils. We predict that the conversion of farmland into prairie will shift the soil quality, microbial community biomass and microbial community composition in the direction of native prairies, but with the restoration methods tested it may take many decades to approach the levels found in a virgin prairie throughout the soil profile.     

Leaf litter is the main driver for changes in bacterial community structures in the rhizosphere of ash and beech

The rhizosphere and the surrounding soil harbor an enormous microbial diversity and a specific community structure, generated by the interaction between plant roots and soil bacteria. The aim of this study was to address the influences of tree species, tree species diversity and leaf litter on soil bacterial diversity and community composition. Therefore, mesocosm experiments using beech, ash, lime, maple and hornbeam were established in 2006, and sampled in October 2008 and June 2009. Mesocosms were planted with one, three or five different tree species and treated with or without litter overlay.Cluster analysis of DGGE-derived patterns revealed a clustering of 2008 sampled litter treatments in two separated clusters. The corresponding treatments sampled in 2009 showed separation in one cluster. PCA analysis based on the relative abundance of active proteobacterial classes and other phyla in beech and ash single-tree species mesocosm indicated an effect of sampling time and leaf litter on active bacterial community composition. The abundance of next-generation sequencing-derived sequences assigned to the Betaproteobacteria was higher in the litter treatments, indicating a higher activity, under these conditions. The Deltaproteobacteria, Nitrospira and Gemmatimonadetes showed an opposite trend and were more active in the mesocosms without litter. The abundance of alphaproteobacterial sequences was higher in mesocosms sampled in 2009 (P = 0.014), whereas the Acidobacteria were more active in 2008 (P = 0.014). At the family level, we found significant differences of the litter vs. non-litter treated group. Additionally, an impact of beech and ash as tree species on soil bacterial diversity was confirmed by the Shannon and Simpson indices. Our results suggest that leaf litter decomposition in pH-stable soils affect the soil bacterial composition, while tree species influence the soil bacterial diversity.