不同有机肥对烟田土壤微生物的影响

为了解施用不同有机肥对烟田土壤微生物数量的影响进行了本试验。试验采用5种不同有机肥处理,对照为纯化肥处理。采用平板稀释法,分别分离计数烟田土壤中真菌、细菌、放线菌的数量。结果表明:与对照相比,施用有机肥均能提高烟田土壤微生物的数量。其中,施用化肥+鸡粪的烟田土壤微生物数量最高,同时烟叶的品质也最好;其次是化肥+牛粪秸秆。试验结果表明,土壤中真菌与放线菌的数量变化趋势相似,而细菌的数量变化趋势与土壤微生物总量变化相似。     

原油经微生物降解后组份变化研究

为筛选复合菌优良菌种,探讨了经不同微生物降解后原油的组份变化。在试验条件下选用5种不同的菌种LH1、98—25、W4、r1、MBS,以新疆油田原油K92为唯一碳源,在37℃时摇床培养10d,测定了培养液表面张力,并对微生物作用后的原油全烃气相色谱进行了分析,用内标法分析了正构烷烃的分布。研究发现,菌种MBS、W4和98—25表面张力值下降比较明显,从65．1mN／m分别降到55．4mN／m、56．2mN／m和58．1mN／m,依次下降了14．90％、13．67％和10．75％;全烃分析发现MBS和r1为良好的烃降解菌株,LH1对C14～C28烃有较好的降解优势,98-25对C29～C31烷烃有较好的降解优势。     

不同纤维素分解菌纤维素酶活性比较试验

以滤纸为唯一碳源的无机盐溶液作为培养基,对拟康宁木霉(Trichoderma koningiopsis)、黄绿木霉(Trichoderma aureoviride)和绿色木霉(Trichoderma viride)这3种纤维素分解菌进行了培养及羧甲基纤维素CMC酶活性测定。结果显示:拟康宁木霉和绿色木霉的滤纸失重率分别达到37%、33%,是黄绿木霉的6～7倍,且他们的CMC酶活性也显著黄绿木霉。表明不同的菌株对纤维素类物质的分解能力差异很大,且CMC酶活性高的菌种滤纸分解能力也比较明显,以拟康宁木霉与绿色木霉分解纤维素的能力较强。     

石羊河中下游不同退耕年限次生草地土壤理化及生物学特性研究

测定并分析了石羊河中下游不同退耕年限次生草地土壤理化(含水量、有机碳、硝态氮、铵态氮、全磷、有效磷、全钾、速效钾、缓效钾)及生物学(微生物量碳、氮、磷及真菌、细菌、放线菌数量)特性。结果表明,随退耕年限的延长,各土层(0~10 cm,10~20 cm,20~30 cm,30~40 cm)土壤铵态氮及全磷呈下降趋势;土壤含水量、有机碳、硝态氮、有效磷、有效钾及缓效钾呈上升趋势;全钾与速效钾随退耕年限的变化不显著;除30~40 cm土层外,各土层土壤微生物量碳在退耕较短年限内(从1 a到5 a)呈下降的趋势,在退耕较长年限内(从8 a到31 a)呈上升趋势;土壤微生物量氮呈先上升(从1 a到4 a)再下降(从4 a到8 a)最后趋于稳定(从8 a到31 a)的趋势;除0~10 cm土层外,各土层土壤微生物量磷呈先下降(从1 a到2 a)再上升(从2 a到8 a)最后下降(从8 a到31 a)的趋势;不同年限退耕地土壤三大类微生物数量均表现为细菌>放线菌>真菌。     

南岭小坑果园土壤微生物数量状况初步研究

研究了韶关市曲江小坑果园表层土壤(0~20 cm)和亚表层土壤(20~40 cm)中细菌、放线菌、真菌数量状况及垂直分布特点.结果表明:(1)果园中土壤微生物数量在土壤中具有明显的垂直分布特征,土壤微生物数量随土壤深度的增加而递减.表层土壤的3种微生物总数高于亚表层(p=0.001),是亚表层的4.03倍.(2)表层与亚表层土壤中的细菌数量均远高于同层的放线菌、真菌的数量,前者约占微生物总量的80%,后两者各占微生物总数的10%左右.(3)果园土壤微生物数量随不同时间而变化,总体变异系数为8.7%,且不同土壤深度的微生物数量变化存在明显差异(p=0.001).表层土壤的微生物数量变动系数(10.7%)为亚表层土壤变动系数(1.3%)的8.2倍.     

The role of soil chemical properties,land use and plant diversity for microbial phosphorus in forest and grassland soils

Management intensity modifies soil properties, e.g., organic carbon (C_org) concentrations and soil pH with potential feedbacks on plant diversity. These changes might influence microbial P concentrations (P_mic) in soil representing an important component of the P cycle. Our objectives were to elucidate whether abiotic and biotic variables controlling P_mic concentrations in soil are the same for forests and grasslands, and to assess the effect of region and management on P_mic concentrations in forest and grassland soils as mediated by the controlling variables. In three regions of Germany, Schwäbische Alb, Hanich‐Dün, and Schorfheide‐Chorin, we studied forest and grassland plots (each n = 150) differing in plant diversity and land‐use intensity. In contrast to controls of microbial biomass carbon (C_mic), P_mic was strongly influenced by soil pH, which in turn affected phosphorus (P) availability and thus microbial P uptake in forest and grassland soils. Furthermore, P_mic concentrations in forest and grassland soils increased with increasing plant diversity. Using structural equation models, we could show that soil C_org is the profound driver of plant diversity effects on P_mic in grasslands. For both forest and grassland, we found regional differences in P_mic attributable to differing environmental conditions (pH, soil moisture). Forest management and tree species showed no effect on P_mic due to a lack of effects on controlling variables (e.g., C_org). We also did not find management effects in grassland soils which might be caused by either compensation of differently directed effects across sites or by legacy effects of former fertilization constraining the relevance of actual practices. We conclude that variables controlling P_mic or C_mic in soil differ in part and that regional differences in controlling variables are more important for P_mic in soil than those induced by management.     

金沙江干热峡谷中退化的土壤生态系统生物学特征初探

Distribution characteristics of soil animals,microorganisms and enzymatic activity were studied in the dry red soil and Vertisol ecosystems with different degradation degrees in the Yuanmou dry hot valley of the Jinsha River,China.Results showed that Hymenoptera,Araneae and Collembola were the dominant groups of soil animals in the polts studied.The numbers of groups and individuals and density of soil animals in the dry red soil series were higher than those in the Vertisol series,and the numbers of individuals and density of soil animals decreased with the degree of soil degradation.Bacteria dominated microbiococnosis not only in the dry red soils but also in the Vertisols.Microbial numbers of the dry red soil series were higher than those of Vertisol series,and decreased with the degree of soil degradation.The activities of catalase,invertase,urease and alkaline phosphatase declined with the degradation degree and showed a significant decline with depth in the profiles of both the dry red soils and the Vertisols,but activities of polyphenol oxidase and acid and neutral phosphatase showed the same tendencies only in the Vertisols.It was concluded that the characteristics of soil animals,microorganisms and enzymatic activity could be used as the bio-indicators to show the degradation degree of the dry red soils and Vertisols.Correlation among these soil bio-indicators was highly significant.     

土壤中恩诺沙星的吸附-解吸特性和生物学效应

抗生素药物残留对生存环境的影响已受到人们广泛的关注。本文研究了我国应用较为广泛的抗生素恩诺沙星在几种农业土壤中的吸附和解吸特性及其对土壤微生物区系和有机碳矿化的影响。结果表明,土壤对恩诺沙星具有较强的吸附作用,残留在土壤中的低量恩诺沙星主要被吸附在固体颗粒上,不易释放和随水迁移。但残留在土壤中的恩诺沙星可影响土壤微生物数量和有机碳的矿化。低浓度的恩诺沙星可刺激土壤微生物活性,增加土壤有机碳的矿化;高浓度的恩诺沙星则会抑制土壤微生物活性和有机碳的矿化。恩诺沙星对土壤生物学性质影响的持续时间较短,约10天左右,这可能与土壤对恩诺沙星具强吸附作用及恩诺沙星在土壤中自然降解削弱了其活性等有关。     

不同茶园土壤微生物数量状况调查初报

调查了全省14个茶场17块茶园土壤微生物的数量状况,结果表明：茶园土壤微生物总数为每克于土1000万个以上,多的达到5800多万个,远较一般农田和旱土的土壤微生物数量大。三大类群微生物中以细菌数量最多,约占总数的90％左右,其次是放线菌,最少的是真菌。凡土层深厚、土质疏松、物理性能较好、有效养分较丰富的茶园,土壤中微生物总量也较高。     

高效纤维素分解菌分离筛选的研究

从土壤、马粪、牛粪等材料中分离出分解纤维素能力较强的高温细菌３个菌群,中温放线菌３株,中温真菌３株。在稻草培养基中,Ｂ１菌群的纤维素酶活力为５．６６ｍｇ·（ｇ·ｈ）－１,Ａ３菌株的纤维素酶活力为６．５５ｍｇ·（ｇ·ｈ）－１,Ｆ３菌株的纤维素酶活力为５．７６ｍｇ·（ｇ·ｈ）－１,稻草经Ｂ１,Ａ３,Ｆ３分解后,其中的粗纤维含量分别降至６．６９％,６．２６％和６．３５％。