我国南方红壤矿区复垦土壤的微生物生态特征研究Ⅰ对土壤微生物活性的影响

通过对浙江哩浦铜矿废弃地土壤微生物、土壤酶活性及生化作用强度研究表明,与对照土壤相比,矿区土壤微生物总数下降68．43％～80．32％,细菌、放线菌数量减少,但真菌变化不明显,各主要生理类群硝化细菌、氨化细菌、固氮菌、纤维素分解菌数量均呈下降趋势,土壤基础呼吸速率下降;土壤脲酶、蔗糖酶、蛋白酶、酸性磷酸酶、过氧化氢酶、多酚氧化酶和脱氢酶酶活性均有不同程度减弱;土壤硝化作用、氨化作用、固氮作用和纤维素分解强度降低,抑制了矿区土壤C、N的周转速率和能量循环,土壤微生物活性减弱是矿区复垦土壤微生物生态的重要特征之一。     

菠萝-甘蔗轮作的土壤生态效应

通过2000～2002年进行菠萝-甘蔗轮作田间试验,研究了菠萝、甘蔗轮作对甘蔗土壤生态的影响。结果表明：菠萝甘蔗轮作田与甘蔗连作田比较,能明显地改善土壤的通气和蓄水性,加速速效性养分的释放;增强土壤酶活性;增加土壤微生物总量(一般好气性细菌、真菌、放线菌);有益的氨化细菌和硝化细菌成倍增加,而无益的厌氧性细菌、反硝化细菌则受到抑制;固氮菌数量小且变化不大。菠萝-甘蔗轮作对甘蔗土壤生态环境的改善其实质在于：菠萝、甘蔗轮作后,由于其作物种类的不同导致土壤结构的改善和土壤微生物种类和数量增多,土壤生物活性增强,并导致土壤速效养分的增加。     

天津东郊盐碱土微生物分布及土壤酶活性

天津东郊盐碱土微生物分布及土壤酶活性靳素英,崔明学,蔺继尚（中国科学院沈阳应用生态研究所,沈阳１１００１５）Ｄｉｓｔｒｉｂｕｔｉｏｎｏｆｍｉｃｒｏｏｒｇａｎｉｓｍｓｉｎｓａｌｉｎｅ－ａｌｋａｌｉｓｏｉｌａｔｃａｓｔｅｒｎｓｕｂｕｒｂｓｏｆＴｉａｎｊｉ...     

Effects of fire on soil respiration,ATP content and enzyme activities in Mediterranean maquis

Question: Do low or high intensity fires affect micro‐organism activity in the upper soil layer of Mediterranean maquis? Location: 600 m from the sea in the Nature Reserve of Castel Volturno (Campania, southern Italy, 40°57’N; 13°55’E). Methods: Soil respiration was measured in situ on intact soil; enzyme activity (cellulase, xylanase, invertase, trehalase and protease) and ATP content were measured on soil samples collected under three species of maquis vegetation: Phillyrea angustifolia L., Myrtus communis L. and Cistus incanus L. Results: Soil microbial respiration showed no significant differences in CO₂ flux in treated and untreated plots, but the ATP content in the soil under C. incanus and M. communis was lower in the treated plots for most of the study period. In the soil under Ph. angustifolia, ATP content was low only for one week after fire. The reduction was more marked in the samples from ‘high fire intensity’ than from ‘low fire intensity’ plots. Soil respiration and ATP content exhibited seasonal variations linked to soil water content. Among the enzyme activity measured in the soil under the three plant covers, only invertase declined in burned plots throughout the study period, particularly in the ‘high fire intensity’ plots. Activity of the enzymes cellulase, xylanase, trehalase and protease had a different sensitivity depending on the respective shrub cover. Conclusions: Impact of fire on soil microbial activity is largely dependent on vegetation mosaic and species identity.     

Comparison of crop productivity and soil microbial activity among different fertilization patterns in red upland and paddy soils

Soil enzyme activity and microorganism community can be changed through different long-term fertilization patterns. However, the effect of different fertilization practices on soil microorganisms might differ among crop systems. The objective of the study was to reveal the change of soil enzyme activity and soil microorganism community in different fertilizations both in upland and paddy soils. Therefore, based on long-term fertilization experiments in upland soil started in 1986 and adjacent paddy soil experiment commenced in 1981, with both consisting of 4 treatments: Control (no fertilization), N (only nitrogen fertilizer), NPK (nitrogen, phosphate and potassium fertilizers) and NPKM (nitrogen, phosphate and potassium fertilizers plus organic manure), grain yield, soil fertility, activities of soil urease, catalase, acid phosphatase, microorganism community (the number of bacteria, fungus and actinomycete) were analyzed. The result showed that: the highest grain yield was attained under the application of chemical fertilizers plus manure, as compared with Control, NPKM significantly increased the grain yield by 908.63% in corn and 118.80% in rice (p < 0.05). Meanwhile, NPKM treatment increased significantly soil organic matter and nutrient contents in upland and paddy soils. Interestingly, there was no significant difference in soil pH among all the treatments of paddy soil, but in upland, NPKM increased pH in comparison to Control by 23.06% (1.15 units of pH). Compared with Control, soil urease, catalase activities, bacteria and actinomycete numbers of NPKM were increased by 321.39%, 129.64%, 229.79%, 85.81% in upland soil, and 25.11%, 251.12%, 292.83%, 196.34% in paddy soil. However, in paddy soil, the soil acid phosphatase activity of Control, NPK and NPKM treatments were higher than upland soil by 34.87%, 44.81%, 52.73% and 30.11%. Then, the soil fungus and actinomycete numbers of paddy soil were lower than upland soil by 20.20% and 88.29%. Therefore, it indicated that long-term application of chemical and organic fertilizers delivered highest productivity in both experiment but the effect of fertilizer practices differed between land uses.     

施肥对日光温室黄瓜生长和土壤生物学特性的影响

采用田间试验研究了施肥对黄土高原日光温室黄瓜生长发育和产量,以及对土壤微生物区系和土壤酶活性的影响。结果表明,施用有机肥和沼肥明显促进了黄瓜生长发育,提高了黄瓜产量,叶面施肥可以降低无机化肥和有机肥用量,施肥对日光温室土壤生物学特性有明显影响,施用有机肥和叶面施肥增加了土壤细菌数量;施用无机化肥和沼肥增加了真菌的数量,施用有机肥降低了真菌的数量;施肥增加了放线菌的数量．同时施肥提高了土壤脲酶、磷酸酶、蔗糖酶活性,但对过氧化氢酶影响较小．施用有机肥提高了脲酶和磷酸酶活性,施用化肥和沼肥对土壤脲酶和土壤磷酸酶活性影响差异不大。     

Effect of exposure to atmospheric pollution on microbial activity in soil

Summary Surface samples of a brown earth soil, showing signs of podzolization were transferred from an unpolluted woodland site and exposed to heavy atmospheric pollution for a period of one year. Although exposure resulted in a decrease in soil pH from 4.2 to 3.7, no significant changes in microbial numbers; nitrification rate; respiration rate; solubilization of insoluble phosphate; or the activity of a range of soil enzymes occurred. The rate of ammonification was, however, higher in the exposed than the control soil.Microbial activity in the unpolluted soil was not, therefore, substantially impaired by exposure to heavy atmospheric pollution, despite the fact that the pH of the soil was reduced.     

化感水稻根际微生物类群及酶活性变化

以化感水稻PI312777（PI）和非化感水稻Lemont（LE）为材料,分别测定不同水稻叶龄期（3～7叶期）根际微生物区系变化及根际土壤酶活性.结果表明,化感水稻明显影响土壤根际微生物类群及相关酶活性.化感水稻PI根际细菌、放线菌、固氮菌的数量高于非化感水稻LE,增幅分别在11.2%～28.3%、40%～78.6%和111.5%～173.9%之间,而真菌数量低于非化感水稻LE,最高仅为其值的25.5％,说明化感水稻PI对绝大多数细菌、放线菌、固氮菌生长有促进作用,对一些真菌生长有抑制作用.进一步分析表明,化感水稻PI对氨化细菌、亚硝酸细菌、硝酸细菌、好气性固氮菌、好气性纤维素分解菌、硫化细菌的生长具有促进作用,其中以氨化细菌、好气性固氮菌的更为明显,最低增幅分别为53.7％和57.6％;而对反硫化细菌、反硝化细菌生长有抑制作用,其值最高分别为非化感水稻的54.2％和50.6％.此外,化感水稻PI根系分泌物对脲酶、磷酸酶、蔗糖酶的活性具有促进作用,而对过氧化氢酶则呈抑制作用.     

Soil textural class plays a major role in evaluating the effects of land use on soil quality indicators

Inappropriate land use that negatively affects ecological processes and soil quality is generally considered to be the primary cause of soil degradation in tropical agroecosystems. We hypothesized that in addition to land use, soil textural class also has an important effect on ecological processes and soil quality. To test our hypothesis, effects of land use change on soil organic fractions as well as microbial and biochemical indicators were quantified for clayey and sandy-clay-loam soils within the native Cerrado biome, pasture (Brachiaria brizantha) and sugarcane (Saccharum officinarum) agroecosystems in southwestern Brazil (Minas Gerais state). Labile carbon, humic substances, soil microbial respiration (SMR), microbial biomass carbon (MBC), metabolic quotient (qCO₂), hydrolysis of fluorescein diacetate (FDA), beta-glucosidase, urease, phosphatase and arylsulphatase activities were measured for each sample. Labile carbon concentrations were not affected by land use but were lower in sandy-clay-loam soil than clayey soil. Humic substances were at the highest concentrations in the native Cerrado and the lowest in sugarcane agroecosystems. Sandy-clay-loam soil had lower humic acid concentrations than clayey soil. Soil microbial indicators (SMR, MBC and FDA) showed lower values in pasture and sugarcane agroecosystems than in the native Cerrado. FDA was a more sensitive microbial indicator than SMR and MBC for detecting land use and textural class differences. The qCO₂ indices were greater in sugarcane systems than in either pasture or native Cerrado systems. The activity of exocellular hydrolytic enzymes, such as beta-glucosidase, urease, phosphatase and arylsulphatase, was smaller in sugarcane and pasture agroecosystems than in native Cerrado ecosystems. Within the same land use, the activity of these enzymes was always greater in clayey soil than in sandy-clay-loam soil, indicating a higher impact of land uses on enzyme activities in clayey soils. Results for the measured indicators support the hypothesis that soil textural class plays a major role in assessing differences between land use systems in the Brazilian Cerrado biome.     

Identification and study of growth and nitrogenase activity of nitrogen fixing cyanobacteria from tropical soil

Identification of cyanobacteria species has been performed on samples coming from two different harvest areas. The most important fixing belongs to Scytonema genus. The other genus identified are Nostoc and Lyngbia. Moreover, these cells are living closely with non-fixing cyanobacteria as well as with bacteria. The growth of cells as well as nitrogenase activity has been studied on a semi-axenic strain of Scytonema, a nitrogen fixing cyanobacterium, isolated from soil crusts. The cell growth is relatively show in liquid medium depleted in combined nitrogen. The growth rate increases when nitrates are supplied to cells. A release of ammonium is observed in medium during cell culture. This release exhibits several maxima and minima during cell growth. The heterocyst cells disappear within four days when filaments are growing in nitrates supplied medium. On the contrary, the heterocyst frequency increases up to more 5% in a nitrogen depleted medium. The heterocyst frequency reaches a maxima after 4 days of culture, then decreases later on. Nitrogenase activity changes during cells growth too. The maximum activity is observed after 5 to 6 days of culture to decrease after even though the cells are still in their exponential phase of growth. Nitrogenase activity increases with light intensity, what indicate a possible relation between photosynthetic and nitrogenase activities.     

秸秆预处理对土壤微生物量及呼吸活性的影响

冬小麦秸秆经8．0g·L^-1H2O2(pH11．0)溶液、12．5g·L^-1 NaOH溶液或H2SO4溶液浸泡8h并80℃烘干后,与无机N一起加入土壤,进行室内25℃恒温培养试验,在不同时间测定土壤微生物量C、N和CO2释放速率。结果表明,培养前期,秸秆预处理使土壤微生物量C数量增加了1．0～1．4倍,但降低了土壤微生物的呼吸活性;培养后期,NaOH和H2SO4处理使土壤微生物量C分别下降了28％和42％,但增加了土壤微生物的呼吸活性;H2O2处理则使土壤微生物量N增加90％;土壤微生物区系中的真菌比例在不同时刻有所增加,表明将秸秆预处理后施入土壤,将对土壤中微生物数量和呼吸活性产生一定影响。     

Microbial responses to nitrogen addition in three contrasting grassland ecosystems

The effects of global N enrichment on soil processes in grassland ecosystems have received relatively little study. We assessed microbial community response to experimental increases in N availability by measuring extracellular enzyme activity (EEA) in soils from three grasslands with contrasting edaphic and climatic characteristics: a semiarid grassland at the Sevilleta National Wildlife Refuge, New Mexico, USA (SEV), and mesic grasslands at Konza Prairie, Kansas, USA (KNZ) and Ukulinga Research Farm, KwaZulu-Natal, South Africa (SAF). We hypothesized that, with N enrichment, soil microbial communities would increase C and P acquisition activity, decrease N acquisition activity, and reduce oxidative enzyme production (leading to recalcitrant soil organic matter [SOM] accumulation), and that the magnitude of response would decrease with soil age (due to higher stabilization of enzyme pools and P limitation of response). Cellulolytic activities followed the pattern predicted, increasing 35–52% in the youngest soil (SEV), 10–14% in the intermediate soil (KNZ) and remaining constant in the oldest soil (SAF). The magnitude of phosphatase response did not vary among sites. N acquisition activity response was driven by the enzyme closest to its pH optimum in each soil: i.e., leucine aminopeptidase in alkaline soil, β-N-acetylglucosaminidase in acidic soil. Oxidative enzyme activity varied widely across ecosystems, but did not decrease with N amendment at any site. Likewise, SOM and %C pools did not respond to N enrichment. Between-site variation in both soil properties and EEA exceeded any treatment response, and a large portion of EEA variability (leucine aminopeptidase and oxidative enzymes), 68% as shown by principal components analysis, was strongly related to soil pH (r = 0.91, P < 0.001). In these grassland ecosystems, soil microbial responses appear constrained by a molecular-scale (pH) edaphic factor, making potential breakdown rates of SOM resistant to N enrichment.     

甘孜州炉霍县不同植被土壤微生物特性初步研究

研究了四川省甘孜州炉霍县不同植被条件下土壤微生物群落的分布状况及两种土壤酶活情况。结果表明,不同植被条件下,土壤微生物类群数量存在差异,草甸土壤微生物群落比森林覆盖土壤的微生物群落多。在同一土壤中,细菌、真菌、放线菌数量随土层深度的增加而降低,0~20cm土层微生物数量高于20~40cm的土层。土壤酶活在土壤剖面中的分布随深度增加而降低。     

Pyrone derivatives from the soil fungus Fusarium solani PSU-RSPG37

Fusarpyrones A (1) and B (2), two new pyrone derivatives, were isolated from the soil fungus Fusarium solani PSU-RSPG37 together with eight known compounds, anhydrofusarubin, fusarubin, 5-hydroxy-8-methoxy-2,4-dimethylnaphtho[1,2,b]furan-6,9-dione, 2,3-dihydro-5-hydroxy-8-methoxy-2,4-dimethylnaphtho[1,2,b]furan-6,9-dione, javanicin, fusalanipyrone, p-hydroxyacetophenone, and tyrosol. The cytotoxic, antimalaria, and antimycobacterial activities of isolated compounds were examined.     

玉米生长期间土壤微生物量与土壤酶变化及其相关性研究

研究了玉米生长期间土壤微生物量碳、氮与土壤过氧化氢酶、蔗糖酶、脲酶、蛋白酶活性变化及其相关性．结果表明，玉米生长前期和中期，土壤微生物量碳、氮及酶活性迅速上升，并逐渐达到最大值；玉米生长后期，土壤微生物量碳、氮、酶活性下降至某一值后并逐渐趋于平稳．几种处理相比较，以秸秆＋尿素处理的土壤微生物量碳、氮及酶活性为最大．除玉米生长后期，土壤微生物量碳、氮与碱解氮、活性腐殖质、土壤ｐＨ不相关外，土壤微生物量碳、氮与土壤过氧化氢酶、蔗糖酶、脲酶、蛋白酶活性及速效养分在玉米生长期间均相关或极相关     

南平溪后杉木林取代杂木林后土壤肥力变化的研究

 本文对福建省南平溪后70年生杉木丰产林与杂木林的土壤肥力进行对比研究。结果表明：与前茬杂木林相比,70年生杉木林下土体较紧实,土壤有机质和营养元素含量降低,土壤酶活性和氧化代谢能力减弱。目前70年生杉木丰产林之所以仍保持较高的土壤肥力水平,主要是杉木林林冠疏开后林下植物多样性提高及生物量增加的缘故。     

不同耕作方式对稻田土壤动物、微生物及酶活性的影响研究

以长期定位试验为基本材料,研究了不同耕作方式对土壤动物、微生物及酶活性的影响．结果表明,0～20cm土壤层内大、中、小型土壤动物垄作免耕为14700个·m^-22,冬水免耕为10450个·m^-22水旱轮作为7950个·m^-22常规平作为6275个·m^-22,垄作免耕处理土壤动物的数量是常规平作的2．34倍．土壤微生物数量和土壤微生物生物量氮因季节而异,总体上是春秋多而夏季少,土壤酶活性表现出表层高,底层低．土壤微生物数量、土壤微生物生物量氮及土壤酶活性不同处理间仍是垄作免耕>水旱轮作>冬水免耕>常规平作,表明垄作免耕有利于改善稻田土壤生态环境。有利于土壤肥力的提高。     

Effects on microbial activity by extraction of indigenous cells from soil slurries

Abstract: Possible effects on the physiological activity and culturability of soil microorganisms by different soil dispersion procedures, and effects on activity caused by extracting bacteria from soil, were investigated. There was no apparent difference in cfu's with dispersion of a silty loam soil and a loamy sand soil with pyrophosphate as compared to dispersion in NaCl. Substrate-induced respiration was reduced in the silty loam soil, and methanol oxidation was reduced in the loamy sand soil with dispersion in pyrophosphate, and the soil pH was irreversibly increased by the treatment. Extracted bacterial fractions had lower numbers of culturable cells as percentage of the total number of bacteria in each fraction, lower respiration rates and no methanol oxidation activity as compared to the soil slurry both before and after extraction. The physiological activity was apparently not affected by the number of cells extracted. This indicates that the increased extraction rate of indigenous soil bacteria obtained by effective disruption of aggregates and detachment of cells from surfaces, only results in increased extraction of cells that have been physiologically changed as a result of the extraction process.     

人类工程活动对青藏高原北部多年冻土融化层及其环境的影响

人类工程活动对多年冻土环境的影响是评价人类工程活动对冻土生态系统影响的重要组成部分.以修建青藏公路时的工程干扰带与非干扰带为对比,研究了人类工程活动对多年冻土环境及其融化层的影响.结果表明,干扰带的融化层厚度比非干扰带要小,在非工程干扰带内,融化层厚度随海拔高度的升高,总体上呈下降趋势;而在工程干扰带内,融化层厚度随海拔高度的变化无规律可循.植被类型对冻土融化层厚度的影响表现为:草原＞灌丛＞草甸.干扰带和非干扰带的土壤含水量垂直分布格局主要受海拔高度的影响,在海拔接近时,受植被状况的影响.人类工程活动对地温的影响表现为干扰带温度低于非干扰带温度.     

土壤团聚体的稳定机制及人类活动的影响

土壤团聚体是土壤结构的基本单位,它的形成不仅是自然的过程,而且受到人类活动的严重影响,即土地利用变化,耕作干扰,有机肥施用以及种植制度和轮作方式等人类活动的影响。土壤结构的改善不仅决定于输入有机碳的总量,而且与有机质的组成和特征有关,因有机质的组成和特征不同,使微团聚体和大团聚体的稳定作用具有不同的机制。