Simulation of annual leaf carbon fluxes and analysis of stand structure of poplars and balck locusts in an alley-cropping system, Brandenburg, Germany

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How much water is used by a black locust (Robinia pseudoacacia L.) short-rotation plantation on degraded soil?

Black locust is a tree species autochthonous from North America, were its distribution range from humid to sub-humid climate. As an early successional and nitrogen-fixing species, black locust grows rapidly as a pioneer tree species under a wide range of site condition. Black locust short-rotation plantations for bioenergy production is raising interest, particularly for those areas were conventional crops systems are economically not profitable. In southern Brandenburg black locust have been successfully used for land reclamation and biomass production in recultivated open-cast lignite mining areas, where nutrient and water resources are limited. An open key question is the water use of the trees under drought conditions which are quite common in these areas. For the determination of transpiration at whole plant level we used a modified wick lysimeter system, which allows us to study plant growth under controlled water regime. Water amount is controlled by the actual evapotranspiration and water demand of the plants and supplied by an automatic drip irrigation system. Transpiration is calculated from the experimental water balance in daily intervals. Photosynthesis is the essential process for biomass productivity including CO2 uptake and water loss controlled by the stomata on the leaf level. Therefore, the ecophysiological response of the plants to drought stress is investigated by using a portable gas exchange system, which allows the measurements of transpiration under various temperature and air humidity regimes. Water use at whole plant level has been linked to their ecophysiological performance

Succession of N cycling processes in biological soil crusts on a Central European inland dune

Biological soil crusts (BSCs) are microbial assemblages that occur worldwide and facilitate ecosystem development by nitrogen (N) and carbon accumulation. N turnover within BSC ecosystems has been intensively studied in the past; however, shifts in the N cycle during BSC development have not been previously investigated. Our aim was to characterise N cycle development first by the abundance of the corresponding functional genes (in brackets) and second by potential enzyme activities; we focussed on the four processes: N fixation (nifH), mineralisation as proteolysis and chitinolysis (chiA), nitrification (amoA) and denitrification (nosZ). We sampled from four phases of BSC development and from a reference located in the rooting zone of Corynephorus canescens, on an inland dune in Germany. BSC development was associated with increasing amounts of chlorophyll, organic carbon and N. Potential activities increased and were highest in developed BSCs. Similarly, the abundance of functional genes increased. We propose and discuss three stages of N process succession. First, the heterotrophic stage (mobile sand without BSCs) is dominated by mineralisation activity. Second, during the transition stage (initial BSCs), N accumulates, and potential nitrification and denitrification activity increases. Third, the developed stage (established BSCs and reference) is characterised by the dominance of nitrificatio

Improving nutrient and water use efficiency of IGNISCUM® – a new bioenergy crop

The new cultivars IGNISCUM Candy® and IGNISCUM Basic® of the Sakhalin Knotweed (Fallopia sachalinensis, Fam. Polygonaceae) are new bioenergy crops, which are characterized by a high annual biomass. The objectives of our study are to investigate (i) the water consumption; (ii) the interrelations between nutrient supply, biomass production, and transpiration; and (iii) the optimization of the biomass production

IMPACT OF THERMAL STRESS AND HIGH VPD ON GAS EXCHANGE AND CHLOROPHYLL FLUORESCENCE OF CITRUS GRANDIS UNDER DESERT CONDITIONS

Additional index words: photosynthesis, photoinhibition, heat stress, temperature Abstract The photosynthetic response of Citrus grandis to high light intensities, low air humidity and high temperature stress was investigated under desert conditions in the southern AravaValley (Israel). During summer, a typical midday stomatal closure was observed even in well-watered trees due to the dramatic increase of the leaf-to-air water vapour deficit. As a result of the reduced transpirational cooling, leaf temperatures increased up to 11 °C above ambient air temperature. The combination of heat stress and photoinhibition resulted in a reversible decrease of photosynthetic activity of Citrus grandis under the extreme summer conditions

Editorial: Ecological Development and Functioning of Biological Soil Crusts After Natural and Human Disturbances

[no abstract available

Monitoring der initialen Bodenentwicklung im künstlichen Wassereinzugsgebiet „Hühnerwasser“

Das Monitoringprogramm im künstlichen Wassereinzugsgebiet „Hühnerwasser“ umfasst u.a. relevante Parameter zur Erfassung der initialen Bodenentwicklung. Aufbau und erste Ergebnisse der initialen Zustandserfassung werden gezeig

READING IN A PORTUGUESE LANGUAGE TEACHING CONTEXT: AN INVITATION TO REFLECTION

This research aims to investigate the beliefs regarding reading and reading activities, in Portuguese classes, introduced by an elementary school teacher as well as to promote discussion of the teacher’s procedures concerning the use of reading and its implications for the development of students. This is a qualitative research, of ethnographic approach (ERICKSON, 1986 e ANDRÉ, 2000), having the teacher’s studies on beliefs (BARCELOS, 2006; SILVA, 2007), reading and teaching (SOLÉ, 1998; KLEIMAN, 2001; SAVELI, 2003; SOARES, 2004) and reflexive development as theoretical reference (PIMENTA; GHEDIN, 2002; ZEICHNER, 2008).  The results of this research demonstrate the reading aloud took prominence in the classroom of the investigated teacher who conceived reading as oralization and as habit formation. The data obtained allowed for starting valuable discussion about the role of reading aloud in the classroom as well as revealed the necessary for the teacher to be aware of the beliefs which steer their pedagogical practices.O objetivo desta pesquisa é investigar as crenças acerca da leitura e das atividades de leitura em aulas de língua portuguesa, apresentadas por uma professora de uma escola da rede pública do ensino fundamental I, bem como promover uma discussão sobre os procedimentos do professor no que diz respeito ao trabalho com a leitura e as suas implicações para o processo de formação dos alunos. Trata-se de uma pesquisa qualitativa, de cunho etnográfico (ERICKSON, 1986; ANDRÉ, 2000), que apresenta como referencial teórico as pesquisas sobre crenças (BARCELOS, 2006; SILVA 2007), leitura e ensino (SOLÉ, 1998; KLEIMAN, 2001; SAVELI, 2003; SOARES, 2004) e formação reflexiva do professor (PIMENTA; GHEDIN, 2002 e ZEICHNER, 2008). &nbsp

Development of biological soil crusts in initial ecosystems in Lusatia, Germany

During initial ecosystem development vegetation cover is sparse, but the space between shrubs is not bare and is often covered by a topsoil biological crust composed by cyanobacteria, green algae, mosses and lichens. These cryptogames are the first colonizer of initial ecosystems. The development of soil surface crusts plays a major role for the further vegetation pattern and ecosystem development through changes to the physico-chemical conditions and influencing various ecosystem processes. We studied the development of biological soil crusts on quaternary substrate of the initial artificial water catchment ´Neuer Lugteich´ located in the former open-cast lignite mining area near Welzow (Brandenburg, Germany). Chlorophyll, Corg, pH were determined to classified various soil crusts types. Some of these Kryptogames excrete exopolysaccharides that bind the inorganic fine-grained particles that form the matrix of the topsoil crust. Due to lack of organic matter in the geological substrate, photoautotrophic organisms like green algae and cyanobacteria are important for soil organic matter accumulation in first millimetre of topsoil of initial ecosystems. The biological soil crusts decrease infiltration rates and influence the hydrological conditions