Storage effects on the community level physiological profiles of Mediterranean forest soils

Community level physiological profiles (CLPPs) have been implemented in many European soil monitoring programmes as a rapid tool for the assessment of the functional properties of soil microbial communities. However, this technique has not been harmonized among different laboratories. In this experiment, the changes of the CLPPs after storage of three Mediterranean forest soils were characterised for two sampling depths. The methods to store the samples were cooling, freezing and room temperature storage. Data presented in this study provide evidence that substantial changes can occur to the soil microbial community functions, regardless of the kind of storage. Changes in functional diversity and substrate evenness depended on the profile and sampling depth. The rate of consumption of the groups of substrates, however, shifted towards an enhanced utilisation of carboxylic acids, phenols and/or amines after 1 month storage at 4 °C, regardless of the profile or sampling depth. This was attributed to the physical disruption of soil aggregates and exposure of relatively recalcitrant occluded organic matter. These effects levelled out during 1-year storage. The great sensitivity of CLPPs to storage treatment suggests to take care for immediate analysis after sampling. In case fresh samples are not available, freezing is recommended as a convenient alternative; in that case, however, the kinetic approach is required for data analysis.     

Effects of antibiotics on soil microorganisms: time and nutrients influence pollution-induced community tolerance

A method for the detection of the effects of antibiotics on soil microbial communities was optimised in the present study. We investigated the influence of measurement time and nutrient status on the pollution-induced community tolerance (PICT), using the sulfonamide sulfachloropyridazine (SCP) as model compound. The tolerance development in soil microcosms that were exposed to SCP under different conditions was compared with the background tolerance in SCP-unexposed microcosms. The tolerance of bacterial extracts from the soil microcosms was determined in Biolog^® multiwell plates as the SCP sensitivity of a range of physiological processes. The background tolerance was not affected by soil nutrient amendments, but an influence of the inoculum density in the microtiter plates was observed. Still, the variance of the background tolerance was low, which is in favour of the usage of community tolerance measurements for a selective detection of a toxicant impact. In line with the assumptions of the PICT concept, soil amendment with SCP led to an increase in community tolerance. This tolerance development was enhanced upon additional soil amendment with fresh pig slurry, and less by alfalfa meal addition. Tolerance increases were observed after a soil exposure to SCP of only 7 days, possibly because nutrient input facilitates the fast adaptation of the soil microbial community. However, a further increase in exposure time led to variable changes in the observed tolerance. Prolonged tolerance detection in the microtiter plates (11 days) enabled a clearer differentiation between different soil treatments, as it better resolved the EC₅₀ values of processes with a high tolerance to bacteriostatic antimicrobial compounds. For the detection of antibiotic effects on soil microbial communities, it is therefore recommended to use nutrient amendments (possibly fresh pig slurry), to standardize the soil exposure time, and to extend the period of Biolog plate measurement beyond 7 days.     

Effect of tillage and N fertilization on microbial physiological profile of soils cultivated with wheat

Microbial diversity might be a good indicator of ecosystem disturbance and functioning. We determined the effect of soil disturbances, such as N fertilization and tillage management, on soil microbial communities in a Typic Argiudoll of the El Salado river basin (Argentina). Microbial activity and substrate utilization provided a metabolic fingerprint of the soil microbial community. Univariate and multivariate analyses were used to differentiate responses to N fertilization and tillage at each of three growth stages of wheat (Triticum aestivum L.). Tillage had an adverse effect on microbial diversity, in which reduced and conventional tillage treated soils had different populations. However, N fertilization also altered microbial diversity depending on the crop developmental stage considered. Metabolism of carboxylic acids and carbohydrates were the main indicators of functional microbial activity and diversity. Although the substrate consumption profile of 32 C substrates did not provide insights into the fundamental ecological interactions that may induce changes in microbial population, it allowed us to demonstrate the alterations of microbial diversity as a result of tillage. We conclude that tillage and N fertilization altered microbial diversity.     

Community composition of ammonia-oxidizing bacteria in the rhizosphere of intercropped wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.), maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.), and faba bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L.)

Cereal/cereal and cereal/legume intercropping systems are popular in the north, northwest, and southwest of China and often result in yield increases compared to monocropping. Rhizosphere interactions may play a significant role in the yield increases, particularly with respect to nutrient availability. The aim of this study was to investigate the effects of intercropping on N availability and community composition of ammonia-oxidizing bacteria in the rhizosphere of wheat, maize, and faba bean at different growth stages. Denaturing gradient gel electrophoresis (DGGE) based on 16S rRNA genes was used to analyze the community composition of bacterial ammonia oxidizers belonging to β-proteobacteria. The results showed that intercropping with faba bean significantly increased nitrate concentrations in the rhizosphere of wheat and maize at the second sampling time (20 June) compared to monocropping or intercropping between maize and wheat. Intercropping significantly affected the community composition of ammonia-oxidizing bacteria in the rhizosphere compared to monocropping, and the effects were most pronounced in the maize/faba bean and wheat/maize intercropping systems when faba bean and wheat were at anthesis and maize was in seedling stage. In wheat/faba bean intercropping, the effects of intercropping on community composition of ammonia-oxidizing bacteria were less pronounced at the seedling stage of the two species but were significant at anthesis.     

中国寒温带,温带落叶松林群落生物量的研究概述

文章系统地分析了中国寒温带、温带落叶松林主要群落类型的群落学特征，以及兴安落叶松林，长白落叶松林，华北落叶松林，阿尔泰落叶松林四种森林群落的生物量，年净生产量及其在不同层次上的分配，并探讨了四种森林群落及不同落叶松种群间的干物质累积速率（ＮＰ／Ｂ）。结果表明：１１６～１３０年生的已郁闭的落叶松林群落生物量和乔木层落叶松生物量：华北落叶松混交林为２７４．８９和２１４．３１ｔ／ｈｍ＾２，长白落叶松林２     

寒地水稻田节肢动物群落多样性调查分析

根据田间系统调查把稻田节肢动物群落按营养和取食关系划分为三个营养层(基位物种、中位物种、顶位物种)和不同的功能集团,在物种、功能集团和营养层三个组织层次水平上分析了稻田节肢动物群落的结构和多样性。结果表明:三类稻田中,施生物药剂稻田的生态稳定性最好,自然稻田的生态稳定性好于施化学药剂稻田的生态稳定性。     

Creating space for sustainable food systems: Lessons from the field

In response to growing trendsin the current food system toward globalintegration, economic consolidation, andenvironmental degradation, communities haveinitiated alternative, more sustainable foodand agricultural systems. Lessons may now belearned about the development and maintenanceof local, sustainable food systems projects –those that attempt to integrate theenvironmental, economic, and social health oftheir food systems in particular places. Fourkinds of space need to be created and protected– social space, political space, intellectualspace, and economic space. Three importantthemes emerge from these community spaces:public participation, new partnerships, and acommitment to social, economic, andenvironmental justice principles.     

上海地区绿化植物综合评价与群落构建

选择了上海地区常见的82种绿化植物,包括乔木、灌木(包括小乔木)、藤本地被植物3种类型,对其固碳、滞尘、吸污、杀菌4个方面的生态功能进行了综合评价和分级,并在此基础上构建了4种功能型的复层结构群落。     

庞泉沟自然保护区周边农田甲虫群落调查

2006年6~8月,在山西庞泉沟国家自然保护区(111°22'~111°33'E,37°45'~37°55'N)周边的农田(海拔1 600~1 640m),包括玉米田、马铃薯田、莜麦田、胡麻田、大豆田、退耕还林地和荒地,利用巴氏罐诱法,并结合网筛、扫网等采集方法对甲虫群落进行了初步调查,共获标本1980号,隶属13科。优势类群为步甲科Carabi-dae,占总捕获量的74.04%。并结合该地区的农田耕作方式对不同功能类群的种类及数量分布进行分析。     

不同类型茶园捕食性天敌群落相似性研究

采用群落种组成相似性分析、群落组成相似性分析和群落特征相似性分析3种方法,研究了祁红产区等高茶园、平地茶园和坡地茶园3种茶园类型及春茶、夏茶和秋茶3个生育期捕食性天敌群落的相似性。结果表明,群落种组成相似性平均水平的排序为不同类型茶园相同生育期>不同类型茶园不同生育期>同一类型茶园不同生育期>同一类型茶园相邻生育期。坡地茶园秋茶、平地茶园夏茶和秋茶以及等高茶园秋茶的群落组成最为相似;而平地茶园和坡地茶园春茶次之。等高茶园和平地茶园春茶的群落特征最相似,其次为3种类型茶园秋茶及平地茶园夏茶。