Soil microbial activity and nutrients of evergreen broad-leaf forests in mid-subtropical region of China

To better understand the effects of forest suc-cession on soil microbial activity, a comparison of soil microbial properties and nutrients was conducted between three forest types representing a natura...     

基于Web Service和元数据的农业生物质 特性数据共享平台研究

农业生物质特性数据共享平台是实现农业生物质基础性技术参数全社会共享的平台,也是发展优质、 高效、低耗生物质产业的公益性基础。其关键在于如何将区域存储分散、数据源不统一的生物质特性数据进行标准 化处理,最终实现共享。通过对平台关键技术的分析,提出以野中心数据库要要数据分节点冶为架构,以元数据和 Web Service 技术为基础的多层次数据共享平台。对平台的实现流程、Web Service 服务流程和元数据服务流程进行 分析,开发了农业生物质特性数据共享平台,平台能实现跨平台和跨操作系统的部署。该软件平台已经投入使用,涉 及农作物秸秆、堆肥、畜禽粪便的化学组成特性、物理和热特性、热化学工程特性以及机械特性方面的数据,能方便 的为用户提供稳定农业生物质特性数据共享服务。     

CERES-Wheat模型中两种蒸发蒸腾量估算方法比较研究

基于CSM-CERES-Wheat模型中Priestley-Taylor(PT)和FAO56 Penman-Monteith(PM)2种蒸发蒸腾量估算方法分别模拟了冬小麦2011—2012年和2012—2013年2个生长季的累积蒸发蒸腾量、日蒸发蒸腾量、土壤含水率、地上干物质以及籽粒产量,并对2种方法的模拟结果进行了评价和比较。对2种方法模拟的蒸发蒸腾量值与试验区域内大型称量式蒸渗仪的实测结果进行了比较,结果表明,基于PT和PM方法的CERES-Wheat模型均可以准确地模拟干旱-半干旱地区冬小麦的蒸发蒸腾量,累积蒸发蒸腾量和日蒸发蒸腾量的误差分别小于5.4%和3.4%。同时,模型还可以模拟土壤水分动态情况,在0~20 cm土层,CERES-Wheat模型的模拟值与实测值的标准化均方根误差(RRMSEn)为39.38%,模拟结果较差,但20 cm土层以下,2种方法的模拟值与实测值的RRMSEn均小于23.1%,且对40~60 cm土层的模拟结果最好。CERES-Wheat模型基于PT和PM方法对冬小麦在2011—2012年和2012—2013年生长季地上生物量的模拟值与实测值的RRMSEn分别为13.57%和22.76%,产量的RRMSEn分别为11.80%和15.42%,模拟结果均较好。另外,CSM-CERES-Wheat模型基于PT方法模拟的蒸发蒸腾量小于基于PM方法的模拟值,而PT方法对土壤含水率的模拟结果高于PM方法的模拟结果,且PT方法对地上生物量以及产量的模拟结果高于PM方法,用2种方法模拟的成熟期地上生物量及产量的RRMSEn值均在25%以内。总之,CSM-CERES-Wheat模型采用2种方法对蒸发蒸腾量、土壤含水率及干物质和产量的模拟结果均较好,表明该模型在我国干旱-半干旱地区的应用性较好,可为该地区不同水分条件下冬小麦的生长情况提供理论支持。     

Estimated stocks of organic carbon in mangrove roots and sediments in Hinchinbrook Channel,Australia

Aboveground and belowground root biomasses (Babove and Broot) were measured for young, isolated Rhizophorastylosa on Iriomote Island, Japan. The relationship between these two parameters was significant and given as the equation, Broot(g dry weight) = 0.394 × Babove(g dry weight) – 485 (r = 0.986). Multiple regression analyses also revealed good correlation between diameter and biomass of prop roots (Dprop and Bprop) and between prop root and root biomasses. Consequently, root biomass could be estimated from the measurements of diameter and biomass of prop roots using the multiple regression equation, Broot(g dry weight) = 80.0 ×Dprop(cm) + 0.86 ×Bprop (g dry weight) – 251. The relationship between DBH (diameter at breast height) and prop root biomass was also adequately described using an allometric equation.In Hinchinbrook Channel, Australia, redox potential (measured as Eh) and organic carbon stocks in the top 5cm of mangrove sediments were measured along a 600m transect from the frequently inundated, Rhizophora dominated zone on the creek edge, towards higher grounds, where Ceriops spp. became increasingly dominant. Eh values were about –60mV near the creek edge and increased to 260mV on higher grounds. Organic carbon stocks showed an opposite trend to Eh, with the values decreasing from about 360tCha–1 to 160tCha–1. At 18 sites, representing six different habitats, organic carbon stocks were also measured along with the DBH of mangrove trees. DBH was converted into aboveground biomass and then into root biomass using the equations obtained in the study on Iriomote Island. The average organic carbon stocks in the top 50 cm of sediments, aboveground biomass and root biomass were 296tCha–1, 123 tCha–1 and 52 tCha–1, respectively, and accounted for 64%, 25% and 11% of the total organic carbon stock.     

2种果蝇取食后樱桃可培养微生物多样性的动态变化

[目的]确定黑腹果蝇和斑翅果蝇取食后樱桃微生物的动态变化。[方法]利用2种果蝇分别取食樱桃、共同取食樱桃和自然腐烂4种处理方式,经过2、4、6、8、10、12 d后,采用16S r DNA和ITS基因分析的方法分离鉴定樱桃中的微生物。[结果]所有处理共分离鉴定出16种细菌和12种真菌。随着时间的延长,不同处理樱桃中微生物的动态发生了变化。自然腐烂8~12 d的樱桃中微生物种类增多,优势细菌种群为荧光假单胞菌(Pseudomonas fluorescens)和葡萄球菌属(Staphylococcus sp.);黑腹果蝇取食第6天,微生物种类最多,优势细菌种群为厚壁菌门;而斑翅果蝇以及2种果蝇同时取食樱桃2 d后微生物种类就开始增加,可见斑翅果蝇的取食改变了微生物的多样性,从而加快了樱桃腐烂的速度,随后黑腹果蝇形成二次为害;另外,在2种果蝇取食后的樱桃中,白地霉(Geotrichum candidum)是樱桃中较稳定的优势真菌种群,但在自然腐烂的樱桃中并未发现。[结论]该研究可为探索微生物、樱桃、果蝇三者之间的协同进化关系提供理论依据。     

菜地不同施氮量下N2O逸出量的研究

用田间原位密闭气室法和乙炔抑制原状土柱培养法 ,研究了蔬菜地不同施氮量下 N2 O的逸出量。结果表明 ,在一定施氮量范围内 ,N2 O通量随施肥量的增加而上升 ;除最高施肥量 (N4 50 )外 ,N2 O占 (N2 +N2 O)的比率随施肥量的增加而增加。在施肥水平低时 ,氮素的损失以 N2 为主 ,当施肥量高于 30 0 kg/ hm2后 ,则以 N2 O为主。 2 m土体中 NO3- N分析结果表明 ,试验结束时对照和 N4 50 处理土壤剖面中有 NO3- N累积 ,其余各个处理氮素都存在一定程度的损失 ,其中损失量最大的是 N1 50 处理 ,与 N2 O逸出量的趋势相一致。 N2 O逸出量占肥料 N总用量的 0 .15 %～ 0 .6 6 % ,肥料逸出量占土壤 N2 O总逸出量的 39.0 %～ 70 .3% ,且在施氮水平低于 N30 0 以下时 ,N2 O逸出量有随施肥量增加而上升的趋势     

不同产量水平下枣园土壤微生物量碳、氮与土壤和植株养分的关系

【目的】 研究不同产量水平下枣园土壤微生物量碳、氮与不同时期枣园土壤和植株养分的关系,为南疆红枣高产提供土壤管理的理论依据。【方法】 选取南疆高中低3种不同产量水平的枣园为研究对象,采用田间试验,研究不同时期不同产量水平下枣园土壤微生物量碳、氮与不同土层和植株氮、磷、钾养分含量之间的关系。【结果】 土壤碱解氮、速效磷含量随着土壤深度的增加逐渐降低,而速效钾含量逐渐升高。土壤微生物量碳(MBC)和土壤微生物量氮(MBD)含量之间呈极显著正相关,相关系数为0.836 7;土壤微生物量碳与骏枣展叶期0~20 cm土层速效钾含量呈显著正相关,与果实膨大期20~40 cm土层速效钾含量呈显著正相关关系。【结论】 枣园土壤微生物量碳、氮及各养分含量均保持在良好水平,土壤养分及植株养分能对微生物量碳、氮产生显著影响。     

Use efficiency of nitrogen from biodigested plant material by ryegrass

Apparent nitrogen‐use efficiency of the applied mineral N (NUE_min) in effluent from biodigested plant material (BE; C : N_org ratio 14:1; mineral N–to–total N ratio 0.5:1) and a nitrate‐based inorganic fertilizer (IF), both applied at two rates was investigated in a six‐month pot experiment with Italian ryegrass (Lolium multiflorum Lam.). Dry‐matter (DM) production was 7% lower and total amount of N in aboveground biomass was 8% lower in BE than in IF at 40 d after sowing (DAS), equal at 81 DAS, and higher in BE than in IF at 136 and 172 DAS. NUE_min calculated on the basis of accumulated N in aboveground biomass of ryegrass in fertilized treatments compared to a control without N application was significantly lower in BE than in IF up to the third cut (136 DAS). Total NUE_min, total N recovery, and amount of foliage DM were similar for both fertilizers at the end of the experiment. Root biomass, total DM produced including roots and stubble, the fraction of root N to total plant N, and soil mineral N at 172 DAS were higher for BE than for IF. Mineral N applied with biogas‐reactor effluent was almost as effective as the nitrate‐based mineral fertilizer used for comparison. Within the six‐month experimental period net N mineralization, estimated at 12% of organic N in effluent, was not substantial. Hence, the organic compounds in the effluent were relatively recalcitrant.     

福建省主要蔬菜氮磷钾营养特性及其施肥指标体系研究Ⅱ.主要蔬菜氮磷钾施肥效应及其土壤养分丰缺指标

采用田间试验研究福建主要蔬菜氮磷钾施肥效应,建立菜田速效氮磷钾丰缺指标.根据148个试验的空白区产量水平,将土壤肥力分为“高”、“中”和“低”3个等级.结果表明,土壤肥力对蔬菜产量贡献率为(50.9士12.8)％,随土壤肥力等级的降低而明显下降;空白区产量与平衡施肥产量之间存在显著的线性关系.肥效试验结果表明,叶菜类、...     

类人源猪H3N2亚型流感病毒HA,NA遗传进化分析

2007-2008年从吉林省某猪场采集疑似流感发病猪的鼻咽拭子,经病毒分离鉴定获得3株H3N2亚型流感病毒,分别命名为A/swine/Jilin/5/2007（Sw/Jilin/5/07）、A/swine/Jilin/19/2007（Sw/Jilin/19/07）、A/swine/Jilin/37/2008（Sw/Jilin/37/08）。HA进化树分析结果表明：3株H3N2亚型流感病毒属于近代人源病毒谱系;但是在NA进化树中,Sw/Jilin/37/08株与早期人源和近代人源关系密切,暗示它可能是早期人源和近代人源H3N2亚型猪流感病毒之间的过渡毒株,进一步证实猪在流感病毒种间传播过程中充当＂中间宿主＂作用。