中亚热带不同母质发育森林土壤磷组分特征及其影响因素

本研究以福建三明砂岩和花岗岩发育的米槠林土壤和杉木林土壤为对象,分析土壤磷组分、铁铝氧化物、微生物生物量以及磷酸酶活性等指标,研究母质和森林类型对土壤磷组分的影响程度和机制.结果表明:母质和森林类型显著影响土壤不同磷组分含量.总体上,砂岩发育土壤全磷含量、活性无机/有机磷、中等活性无机/有机磷以及惰性磷含量均显著高于花...     

Changes in soil-microbe-exoenzyme C:N:P stoichiometry along an altitudinal gradient in Mt. Datudingzi,Northeast China

海拔变化导致温度、水分、植被等条件的改变会显著影响土壤碳(C_soil)、氮(N_soil)、磷(P_soil)含量及其化学计量特征, 土壤微生物如何通过调整自身生物量和胞外酶化学计量特征进行适应仍不明确。为了研究海拔梯度变化对土壤微生物生物量和胞外酶活性的影响, 探索土壤-微生物-胞外酶C:N:P化学计量特征间的协变性, 该文以黑龙江省雪乡大秃顶子山800、1 100、1 600和1 700 m分布的典型生态系统(针阔混交林、针叶林、岳桦林和草地)为研究对象, 测定其C_soil、N_soil、P_soil含量, 微生物生物量C (C_mic)、N (N_mic)、P (P_mic)含量, 以及微生物获取C (β-1, 4-葡萄糖苷酶, BG), N (几丁质酶, NAG), P (酸性磷酸酶, AP)资源的相关胞外酶活性。结果表明: (1)海拔梯度变化对C_soil和C_mic含量没有显著影响; 不同海拔间土壤和微生物生物量N、P含量存在显著差异。(2) BG和NAG活性随着海拔的升高呈现显著降低趋势, 表明海拔升高导致的温度降低抑制了微生物的活性。(3)海拔对土壤C:N、微生物C:N:P以及胞外酶C:N:P均具有显著影响。胞外酶C:N:P随着微生物与土壤间C:N:P化学计量不平衡性(土壤C:N:P与微生物C:N:P的比值)的增加而逐渐降低。微生物可以通过调整自身生物量以及胞外酶C:N:P适应土壤化学计量特征的变异, 该结果支持了微生物的资源分配理论。     

Microbial biomass and growth kinetics of microorganisms in chernozem soils under different land use modes

The carbon content of microbial biomass and the kinetic characteristics of microbial respiration response to substrate addition have been estimated for chernozem soils under different land use: arable lands used for 10, 46, and 76 years, mowed meadow, natural forest, and forest shelter belt. Microbial biomass and the content of microbial carbon in humus (C_mic /C_org) decreased in the following order: soils under forest cenoses—mowed meadow—10-year arable land—46- and 75-year arable land. The amount of microbial carbon in the long-plowed horizon was 40% of its content in the upper horizon of natural forest. Arable soils were characterized by a lower metabolic diversity of microbial community and by the highest portion of microorganisms able to grow directly on glucose introduced into soil. The effects of different scenarios of carbon sequestration in soil on the amounts and activity of microbial biomass are discussed.     

Microbial biomass and growth kinetics of microorganisms in chernozem soils under different farm land use modes

The carbon content of microbial biomass and the kinetic characteristics of microbial respiration response to substrate introduction have been estimated for chernozem soils of different farm lands: arable lands used for 10, 46, and 76 years, mowed fallow land, non-mowed fallow land, and woodland. Microbial biomass and the content of microbial carbon in humus (Cmic/Corg) decreased in the following order: soils under forest cenoses-mowed fallow land-10-year arable land-46- and 75-year arable land. The amount of microbial carbon in the long-plowed horizon was 40% of its content in the upper horizon of non-mowed fallow land. Arable soils were characterized by a lower metabolic diversity of microbial community and by the highest portion of microorganisms able to grow directly on glucose introduced into soil. The effects of different scenarios of carbon sequestration in soil on the reserves and activity of microbial biomass are discussed.     

Livestock exclusion reduces the spillover effects of pastoral agriculture on soil bacterial communities in adjacent forest fragments

Forest-to-pasture conversion is known to cause global losses in plant and animal diversity, yet impacts of livestock management after such conversion on vital microbial communities in adjoining natural ecosystems remain poorly understood. We examined how pastoral land management practices impact soil microorganisms in adjacent native forest fragments, by comparing bacterial communities sampled along 21 transects bisecting pasture–forest boundaries. Our results revealed greater bacterial taxon richness in grazed pasture soils and the reduced dispersal of pasture-associated taxa into adjacent forest soils when land uses were separated by a boundary fence. Relative abundance distributions of forest-associated taxa (i.e., Proteobacteria and Nitrospirae) and a pasture-associated taxon (i.e., Firmicutes) also suggest a greater impact of pastoral land uses on forest fragment soil bacterial communities when no fence is present. Bacterial community richness and composition were most related to changes in soil physicochemical variables commonly associated with agricultural fertilization, including concentrations of Olsen P, total P, total Cd, delta ¹⁵N and the ratio of C:P and N:P. Overall, our findings demonstrate clear, and potentially detrimental effects of agricultural disturbance on bacterial communities in forest soils adjacent to pastoral land. We provide evidence that simple land management decisions, such as livestock exclusion, can mitigate the effects of agriculture on adjacent soil microbial communities.     

酶化学计量揭示5年氮添加加剧毛竹林土壤微生物碳磷限制

土壤胞外酶活性和酶化学计量比能很好地反映土壤养分有效性和微生物对养分的需求变化。然而,氮(N)沉降对亚热带森林土壤微生物养分相对限制情况的影响尚不清楚。通过在亚热带毛竹林进行N添加试验来模拟N沉降,并在试验满5年时进行取样,测定不同处理下土壤养分和与碳(C)、N、磷(P)循环相关的酶活性,利用酶化学计量比及矢量分析探究微生物的养分分配情况。结果表明: N添加显著降低土壤可溶性有机碳、有效磷含量,显著提高有效氮含量。此外,N添加显著降低β-N-乙酰氨基葡糖苷酶(NAG)活性和NAG/微生物生物量碳(MBC),显著提高酸性磷酸酶(ACP)和ACP/MBC。低N和中N处理显著提高酶C/N、矢量长度和矢量角度,但显著降低酶N/P。冗余分析表明,N添加下,土壤有效磷含量的变化是影响土壤酶活性及酶化学计量比变化的主要因子。综上可知,N添加改变了微生物的养分获取策略,即通过减少分配给合成N获取酶的养分来增加合成P获取酶的养分。此外,N添加还加剧了微生物的C、P限制,未来可以施加适量P肥来提高亚热带毛竹林的土壤肥力。     

Soil microbial responses to elevated phosphorus and pH in acidic temperate deciduous forests

Although northern temperate forests are generally not considered phosphorus (P) limited, ecosystem P limitation may occur on highly weathered or strongly acidic soils where bioavailable inorganic P is low. In such environments, soil organisms may compensate by increasing the utilization of organic P via the production of extracellular enzymes to prevent limitation. In this study, we experimentally increased available P and/or pH in several acidic eastern deciduous forests underlain by glaciated and unglaciated soils in eastern Ohio, USA. We hypothesized that where inorganic P is low; soil microbes are able to access organic P by increasing production of phosphatase enzymes, thereby overcoming biogeochemical P limitations. We measured surface soil for: available P pools, N mineralization and nitrification rates, total C and N, enzymes responsible for C, N, and P hydrolysis, and microbial community composition (PLFA). Increasing surface soil pH a whole unit had little effect on microbial community composition, but increased N cycling rates in unglaciated soils. Phosphorus additions suppressed phosphatase activities over 60% in the unglaciated soils but were unchanged in the glaciated soils. All treatments had minimal influence on microbial biomass, but available pools of P strongly correlated with microbial composition. Microbes may be dependent on sources of organic P in some forest ecosystems and from a microbial perspective soil pH might be less important overall than P availability. Although our sampling was conducted less than 1 year after treatment initiation, microbial community composition was strongly influenced by available P pools and these effects may be greater than short-term increases in soil pH.     

Ecoenzymatic stoichiometry of microbial nutrient acquisition in tropical soils

The relative activities of soil enzymes involved in mineralizing organic carbon (C), nitrogen (N), and phosphorus (P) reveal stoichiometric and energetic constraints on microbial biomass growth. Although tropical forests and grasslands are a major component of the global C cycle, the effects of soil nutrient availability on microbial activity and C dynamics in these ecosystems are poorly understood. To explore potential microbial nutrient limitation in relation to enzyme allocation in low latitude ecosystems, we performed a meta-analysis of acid/alkaline phosphatase (AP), β-1,4-glucosidase (BG), and β-1,4-N-acetyl-glucosaminidase (NAG) activities in tropical soils. We found that BG:AP and NAG:AP ratios in tropical soils are significantly lower than those of temperate ecosystems overall. The lowest BG:AP and NAG:AP ratios were associated with old or acid soils, consistent with greater biological phosphorus demand relative to P availability. Additionally, correlations between enzyme activities and mean annual temperature and precipitation suggest some climatic regulation of microbial enzyme allocation in tropical soils. We used the results of our analysis in conjunction with previously published data on soil and biomass C:N:P stoichiometry to parameterize a biogeochemical equilibrium model that relates microbial growth efficiency to extracellular enzyme activity. The model predicts low microbial growth efficiencies in P-limited soils, indicating that P availability may influence C cycling in the highly weathered soils that underlie many tropical ecosystems. Therefore, we suggest that P availability be included in models that simulate microbial enzyme allocation, biomass growth, and C mineralization.     

滇西并流河谷区土壤酶活性化学计量学特征与环境因子的关系

横断山河谷区具有极高的景观异质性,气候与植被类型多样化程度较高。为探讨土壤C、N、P、S四种生物元素在滇西怒江、澜沧江、金沙江及元江并流河谷区的区域循环特征,在各河谷的森林、草地、农田中分别取浅层(0～10 cm)土样,测定了土壤中C、N、P、S的循环酶,即β-葡萄糖苷酶(BG)、N-乙酰-β-D-氨基葡萄糖苷酶(NAG)、酸性磷酸酶(AP)、硫酸脂酶(SU)活性,分析了土壤酶活性及其化学计量学特征与环境因素之间的关系。结果表明: 不同流域和不同土地类型下AP、NAG活性均有显著差异;4种酶活性之间均呈显著正相关,BG、NAG、SU活性由东南向西北随采样点的海拔升高而逐渐升高;在各流域土壤中,酶活性的生态化学计量比均为AP∶SU > BG∶SU > NAG∶SU > BG∶NAG > BG∶AP > NAG∶AP;与各流域内的林地和草地相比,农田土壤BG∶NAG较高,而NAG∶AP较低(元江流域除外);农田土壤中AP∶SU、BG∶SU、NAG∶SU在元江流域小于草地和林地,在澜沧江流域和金沙江流域则大于林地而小于草地。土壤酶活性及其化学计量学特征受到土壤理化性质、气候及区位的综合影响,其中土壤理化性质的影响最大。农业活动对C∶N∶P相关酶化学计量学特征具有显著影响,降低了土壤中N分解酶与其他酶活性的计量比,表现为增加了BG∶NAG,降低了NAG∶AP,农业活动对其他酶化学计量学特征的影响较小。     

东北丘陵区林地转型耕地对土壤编码碱性磷酸酶基因的细菌群落的影响

【目的】通过研究林地转型耕地对土壤编码碱性磷酸酶基因的细菌群落丰度、多样性和结构的影响,为丘陵区耕地长期施肥下农田土壤微生物多样性丧失的影响机制以及未来的退耕还林过程中土壤微生物多样性的提升和土地可持续利用研究提供一些基础数据和技术支撑。【方法】采用实时荧光定量PCR (real-time quantitative PCR,qPCR)和高通量测序技术解析土壤编码碱性磷酸酶基因的细菌群落的丰度、多样性和结构变化,并耦合土壤化学性质分析,明确土壤编码碱性磷酸酶基因的细菌群落丰度和多样性与土壤化学性质的关系以及关键的驱动因子。【结果】林地垦殖为农田后,长期施肥导致土壤酸化,pH从5.58降至4.72,而土壤速效磷则从2.49 mg/kg增至49.3 mg/kg。相应地,耕地土壤编码碱性磷酸酶基因的细菌群落的丰度和Shannon指数均显著低于林地。基于编码碱性磷酸酶的phoD基因(alkaline phosphatase-encoding gene)序列的物种分类表明,丘陵区土壤编码碱性磷酸酶基因的细菌群落的优势门为变形菌门(Proteobacteria)、蓝藻门(Cyanobacteria)、浮霉菌门(Planctomycetes)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)和疣微菌门(Verrucomicrobia),其中林地土壤的蓝藻门的相对丰度显著高于耕地。耕地土壤的慢生根瘤菌属(Bradyrhizobium)和芽孢杆菌属(Bacillus)的相对丰度显著高于林地,而中慢生根瘤菌属(Mesorhizobium)、假单胞菌属(Pseudomonas)、Chlorogloea属、Gemmata属、Phormidesmis属和Pseudolabrys属的相对丰度显著低于林地。土壤编码碱性磷酸酶基因的细菌群落结构因林地转型耕地而发生显著改变。phoD基因丰度和Shannon指数与pH显著正相关,而与总磷、速效磷、硝态氮和铵态氮均显著负相关,其中土壤速效磷是这些影响因素中影响最强烈的,长期施用无机磷肥导致含碱性磷酸酶的土壤细菌群落对有机磷分解的能力退化。【结论】林地转型耕地加之长期施肥改变了土壤pH和速效磷,并在其他理化因子的协同驱动下,导致土壤编码碱性磷酸酶基因的细菌群落丰度、多样性和结构的显著变化。     

Changes in heated and autoclaved forest soils of S.E. Australia. II. Phosphorus and phosphatase activity

The effect of soil heat and autoclaving on labile inorganic P (Bray I), microbial P (P-flush) and on phosphatase activity was studied by heating five forest soils in the laboratory, which simulated the effects of heat during bushfires. Top soil was heated to 60 °C, 120 °C and 250 °C or autoclaved for 30 minutes. Soils were analysed immediately after heating and during seven months of incubation to assess immediate and longer-term effects of heating.Labile inorganic P increased immediately after heating and autoclaving soils, with the highest amount recorded for the 250 °C treatment. Phosphorus associated with microbial biomass decreased with heat, and none or small amounts were detected in soils heated to 250 °C and autoclaved, because high temperatures killed the microbial population. Most of the P released from microbes acted as a source of labile inorganic P in soils low in inorganic P, and some of the released P was fixed by the soil. In one soil high in inorganic labile P and with undetectable amounts of microbial-P, the increase in Bray P on heating could only be assigned to solubilisation of other sources of total P Because high temperatures denature enzymatic proteins, phosphatase activity diminished with the increase in temperature, and no activity was detected in 250 °C and autoclaved soils.Phosphorus released by heating decreased during incubation in three of the five soils studied, approaching values observed in unheated soils. Simultaneously, an increase in microbial P was observed in these heated soils, indicating that the partial recovery of microbial biomass acted as a sink for the decrease in Bray-P measured. Phosphatase activity recovered only partially during incubation of heated soils.     

Changes in phosphorus fractions caused by increased microbial activity in forest soil in a short-term incubation study

The effects of adding larch (Larix kaempferi) leaf litter and nitrogen (N) on microbial activity and phosphorus (P) fractions in forest soil were examined in a short-term (28-d) laboratory incubation study. The soil was analyzed using a modified Hedley sequential extraction procedure and an acid phosphatase assay. The addition of larch litter and N increased the acid phosphatase activity and decreased the labile P (H₂O-P + NaHCO₃-P) concentration. Compared with addition of larch litter only, addition of both inputs decreased the proportion of inorganic P (Pi) and increased that of organic P (Po) in the NaOH fraction, bound to aluminum and iron oxides. The results of nutrient (carbon, N, or P) addition indicated that acid phosphatase was synthesized to acquire P. This study suggests that, in this forest soil, P in the H₂O-P + NaHCO₃-P and in the NaOH-Pi fractions was available for soil microorganisms to decompose leaf litter and that increase in microbial activity eventually translated in an increase in the proportion of Po found in the NaOH fraction in this forest soil.     

Differences in Arbuscular Mycorrhizal Fungal Community Composition in Soils of Three Land Use Types in Subtropical Hilly Area of Southern China

Land use type is key factor in restoring the degraded soils due to its impact on soil chemical properties and microbial community. In this study, the influences of land use type on arbuscular mycorrhizal fungal (AMF) community and soil chemical properties were assessed in a long-run experimental station in subtropical hilly area of southern China. Soil samples were collected from forest land, orchard and vegetable field. Soil chemical properties were analyzed, and PCR-DGGE was performed to explore the AMF community structure. Cloning and sequencing of DGGE bands were conducted to monitor AMF community composition. Results indicate that the contents of total P, available P and available K were the highest while the contents of soil organic matter, total N, total K and available N were the lowest in vegetable field soils, with forest land soils vice versa. According to DGGE profiling, AMF community in forest soils was more closely related to that in orchard soils than that in vegetable field soils. Sequencing indicated that 45 out of 53 excised bands were AMF and 64.4% of AMF belonged to Glomeraceae, including some “generalists” present in all soils and some “specialists” present only in soils of particular land use. Category principle component analysis demonstrated that total N, soil organic matter and available P were the most important factors affecting AMF community, and some AMF phylotypes were closely associated with particular soil chemical properties. Our data suggest that AMF communities are different with different land use types.     

不同环境条件下土壤微生物对模拟大气氮沉降的响应

研究了林内及林缘两个生境中,在有苔藓覆盖和无苔藓覆盖条件下,人工加氮对土壤理化性质及土壤微生物群落的影响。结果显示加氮使土壤pH下降,有效态氮和有效态磷的含量上升,但不同生境及有无苔藓植物覆盖在一定程度上影响土壤理化性质及其对加氮的反应。苔藓植物覆盖可以缓解加氮引起的土壤酸化及有效氮含量上升压力,促进有效态磷含量上升。不同生境中,土壤微生物对氮沉降的响应亦不同。低氮使林缘生境土壤微生物的胁迫程度减小,中高氮使其胁迫程度上升,而任何加氮均增加林内生境中土壤微生物的胁迫程度。两个生境中,苔藓植物覆盖均可以缓解过量氮沉降对土壤微生物造成的压力,降低过量氮沉降对土壤微生物的伤害,提高土壤微生物的代谢活性。     

土壤酶计量揭示了武夷山黄山松林土壤微生物沿海拔梯度的碳磷限制变化

了解土壤胞外酶活性和酶计量的变化对评估山地生态系统土壤养分有效性和微生物的营养限制状况具有重要意义.然而,亚热带山地森林土壤微生物的营养限制状况对海拔梯度变化的响应及其驱动因素尚不清楚.本研究以武夷山不同海拔(1200～2000 m)黄山松林为对象,测定了土壤基本性质、微生物生物量以及与碳(C)、氮(N)、磷(P)循环...     

有机物添加下太岳山油松林土壤微生物元素组成的稳态分析

在山西太岳山地区,向油松林土壤中分别添加生物炭、玉米秸秆、蒙古栎叶、油松叶、木屑等5种有机物,测定各处理的土壤养分、酶及微生物生物量等指标,研究外源有机物添加下土壤酶化学计量特征及微生物元素组成的内稳性。结果表明: 添加木屑显著增加了土壤N(17.1%)、P(37.6%)含量,显著增加了微生物生物量碳(118.0%)、氮(41.0%)、磷(176.6%)。C、N、P获取酶(β-1,4-葡萄糖苷酶、β-1,4-N-乙酰氨基葡萄糖苷酶、亮氨酸氨基肽酶、酸性磷酸酶)活性总体上随添加有机物C/N值(生物炭<蒙古栎叶<油松叶<玉米秸秆<木屑)的增加而增加,其化学计量变化受土壤养分状态及微生物生物量的调控。酶活性相对比例及矢量特性表明,研究区微生物生长受到P的限制,且添加有机物没有缓解P的制约作用。微生物生物量碳、氮及化学计量比C∶N、C:P、N∶P属于绝对稳态型,而微生物生物量磷处于非稳态。微生物通过改变酶的分配策略保持微生物体元素及比例的相对稳定,仅有微生物生物量磷对土壤养分变化表现出不稳定性,可能因为P是研究区微生物生长的限制性元素。     

Do soil aggregates really protect encapsulated organic matter against microbial decomposition?

Soil aggregates can provide an effective protection of organic matter against microbial decomposition as reported by several macroaggregate disruption studies. However, research on the role of aggregation for carbon mineralization was mainly focused on arable soils. In the present study we aim to clarify the impact of aggregation on organic matter protection by measuring carbon mineralization in terms of microbial respiration rates of intact macroaggregates (2–4 and 4–8 mm) and corresponding crushed aggregates from seven topsoil horizons from both arable and forest sites. For two arable and one forest soil we found a significantly (P < 0.001) lower carbon mineralization from intact aggregates as compared to the corresponding crushed material. The portion of aggregate protected carbon reached up to 30% for a grassland soil. For the other arable and forest soils no significant effect of aggregation was found. Similarly, no clear trend could be found for the protective capacity of different size fractions. We conclude that protection by aggregation is effective primarily for soils with a large pool of labile organic matter regardless of their usage as arable land or forest.     

子午岭人工林土壤微生物生物量及酶活性

数十年来,黄土高原的生态恢复取得了显著的效益,不仅遏制了当地的土壤流失,改善了土壤质量,同时也减少了向黄河的输沙量.但是,区域森林物种和群落演替还远未得到充分发展.子午岭林区及其高度发达的森林群落,作为先进的生态区,可以将实践经验和知识借鉴到中国黄土高原的其他地区,有助于确定最有效的人工林树种,以便今后更好地进行生态恢复.为了系统地了解典型的当地树种对土壤性质的潜在影响,本研究以黄土高原子午岭天然次生林区生长状况较好的人工林(刺槐、油松和侧柏)为研究对象,并以子午岭林区顶极群落辽东栎天然林为对照,这4种林型具有较一致的树龄(25年)、立地条件等.采用传统方法测定4种乔木林0～20 cm土壤理化性质、土壤酶活性(蔗糖酶、脲酶和碱性磷酸酶)和土壤微生物生物量碳、氮.结果表明: 1)土壤蔗糖酶活性为16.94～64.49 mg·g^-1·24 h^-1,脲酶活性为0.15～0.26 mg·g^-1·24 h^-1,碱性磷酸酶为0.65～1.23 mg·g^-1·24 h^-1,且侧柏土壤的3种酶活性均显著高于刺槐和油松土壤.从3种酶活性几何平均值来看,侧柏土壤酶活性甚至高于辽东栎;2)土壤微生物生物量碳、氮变化范围分别为247.37～529.84 mg·kg^-1、41.48～77.91 mg·kg^-1,均为侧柏>油松>刺槐,且侧柏显著高于油松和刺槐.辽东栎土壤微生物生物量碳高于侧柏,而微生物生物量氮低于侧柏,但差异均不显著;3)油松土壤溶解性碳、氮含量较高,甚至高于土壤微生物生物量碳、氮,说明油松土壤中溶解性有机物是较微生物生物量更主要的活性养分;4)土壤微生物生物量碳、氮与土壤有机碳和全氮含量呈显著正相关性,刺槐和油松土壤蔗糖酶、脲酶和碱性磷酸酶活性分别与土壤有机碳、全氮和全磷含量呈显著正相关;5)主成分分析结果表明,植被类型对土壤微生物生物量碳和氮、有机碳、全氮、碳磷比、氮磷比、脲酶影响较大,土壤微生物生物量碳、氮、碳磷比、氮磷比和氮与磷呈负相关,土壤溶解性碳、氮与碳氮比呈负相关.表明侧柏是较油松和刺槐更适用于南部森林带的造林树种.     

长期施肥对土壤微生物量及土壤酶活性的影响

 该文以北京国家褐潮土土壤肥力与肥料效益长期监测基地的长期肥料定位试验为平台,研究了长期不同施肥制度对土壤的生物学特性及其土壤酶的影响。主要研究结果：长期撂荒土壤(15年)的有机质和全氮(TN)的含量、微生物量碳(SMB-C)和氮(SMB-N)、土壤的蔗糖酶、磷酸酶和脲酶活性以及SMB-C/SOC(土壤有机碳)和SMB-N/TN比值都高于种植作物的农田土壤;而其代谢商和容重值低于农田土壤。长期施肥的农田(NPK、NPKM 、NPKS和NPKF),其土壤养分含量、微生物量碳和氮以及土壤蔗糖酶、磷酸酶和脲酶活性均高于不施肥的农田(CK);而小麦(Triticum aestivum)-玉米(Zea mays)→小麦-大豆(Glycine max)复种轮作(NPKF)的农田又高于长期复种连作(NPK)的农田;在施肥处理中(NPK、NPKM、NPKS和NPKF),长期化肥与有机肥配合施用的处理(NPKM )的土壤上述指标高于其它施肥处理(NPK、NPKS和NPKF),但其土壤的代谢商、pH值和容重值较低。     

海拔梯度变化对武夷山黄山松林土壤磷组分和有效性的影响

土壤磷（P）是植物生长必需的养分元素,也是亚热带森林生产力的主要限制元素。目前,关于不同海拔土壤P组分和P有效性的变化规律尚无统一定论,其原因主要是忽略了植被类型变化导致的P组分和P有效性对海拔的响应更为复杂。因此,以武夷山不同海拔黄山松林为研究对象,通过测定土壤环境因素、理化性质、微生物生物量（SMB）、酸性磷酸单酯酶（ACP）和磷酸双酯酶（PD）活性以及土壤P组分,探究土壤P组分和P有效性的变化及其影响因素。结果表明,随海拔降低,速效P含量显著增加,而易分解P、中等易分解P、难利用P和总磷含量显著减少。冗余分析结果表明,微生物生物量磷和微生物生物量氮是影响土壤P组分和P有效性变化的关键因素。研究表明,随海拔降低,黄山松林土壤微生物通过提高ACP、PD活性和降低SMB含量的能量分配策略,促进更多较难分解P组分的矿化,从而提高速效P含量,以满足微生物对P的需求。因此,在低海拔地区,微生物通过能量分配策略获取更多有效P,可能有利于提高武夷山黄山松林土壤速效P的供应,但从长期来看,可能使P矿化速率提高和P损耗增加,导致P库的储备不足,不利于土壤P素养分的可持续供应。