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

Fast growing tree species in alley cropping systems and their influence on microclimate in Germany

Paper presented at the 13th North American Agroforesty Conference, which was held June 19-21, 2013 in Charlottetown, Prince Edward Island, Canada.In Poppy, L., Kort, J., Schroeder, B., Pollock, T., and Soolanayakanahally, R., eds. Agroforestry: Innovations in Agriculture. Proceedings, 13th North American Agroforestry Conference, Charlottetown, Prince Edward Island, Canada, June 19-21, 2013.The production of energy wood on arable land has been increased in Germany during the last years. In this context, agroforestry systems keep a prominent position in agriculture, since they allow the simultaneous production of energy wood and food or feed on the same field. Fast growing trees arranged in hedge structures (alley cropping) can have positive effects on microclimate. Results of different research studies carried out in several alley cropping sites located in eastern Germany show that wind velocity can be reduced by more than 50 percent, even though tree hedgerows were not higher than four meters. The observed reduction of wind speed was depending on the distance to trees, on the orientation of tree hedges as well as on the width of the crop alleys. Potentially negative effects on crop yield were expected due to the shading the peripheries of crop alleys by trees. However, first results indicate that the reduction of the global radiation by short rotation trees did no show any negative effect on crop yield. As an exception, the crop yield on a post-mining site was evenly higher near trees compared to the center of crop alleys. In summary, the establishment of alley cropping with fast growing trees have positive effects on microclimate and hence on the yield stability of crops cultivated in between the tree hedgerows without any significantly negative impact on the recent practice of land management.Christian B�hm (1), Michael Kanzler (1) and Dirk Freese (1) ; 1. Brandenburg University of Technology, Chair of Soil Protection and Recultivation, Konrad-Wachsmann-Allee 6, D-03046 Cottbus, Germany.Includes bibliographical references

Potential of Igniscum sachalinensis

The potential of Salix viminalis L. and Igniscum sachalinensis L. for phytoremediation of copper- (Cu-) contaminated soils was studied under greenhouse conditions. Approximately 5 kg of potted agricultural and sewage amended soils sampled from the top 0 to 20 cm depth in Neuruppin, Germany, was treated with CuSO4 at concentrations 0 (control), 250, 750, and 1250 mg Cu kg−1 soil and ethylenediaminetetraacetic acid (EDTA) at 1000 mg kg−1 soil, respectively. Each plant species was grown on four replicates of each soil treatment. Copper accumulated in aboveground tissues tends to increase with increasing soil Cu concentration and was the lowest in stem and leaf of both plant species grown on control soils. At 750 and 1250 mg Cu kg−1 soil, Cu accumulated in stem and leaf of I. sachalinensis increased by over 12- and 20-fold, respectively, whereas there was no vegetative growth in S. viminalis beyond 250 mg Cu kg−1 soil. Application of EDTA to sewage amended soils increased Cu accumulated in the stem and leaf, especially in I. sachalinensis. In general, I. sachalinensis seems to have the potential to tolerate high soil Cu content and simultaneously bioaccumulate Cu in tissues and thus may have better prospects for phytoremediation

An Approach to Thresholds for Evaluating Post-Mining Site Reclamation

Here, a time-scale conceptual threshold model for assessing, evaluating, documenting, and monitoring post-mining sites reclamation progress was developed. It begins from initial state I0 down to degraded state D0 (which depends on the mining). Reclamation starts with soil reconstruction R−2 up to revegetation R−1 (red zones) to reach minimum threshold R0 (amber zone). Beyond R0 are green zones R1, R2, and R3 representing soil/abiotic conditions, biological, and improved threshold, respectively. The model also identifies potential drivers, land-use options, targets, and endpoints along the threshold reclamation ladder. It is applicable to all degraded ecosystems and adoptable in national and international laws. In this approach study, we identified threshold biotic/abiotic indicators for ascertaining success from R0, future work focuses on measurement and ascribing of threshold values to each of the threshold stage

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

Effekte der Agrarholzproduktion auf den Kohlenstoff- und Nährstoffhaushalt des Bodens im Bereich der Lausitzer Bergbaufolgelandschaft

Auf einem Rekultivierungsstandort des Lausitzer Braunkohlereviers wurde vor 4 Jahren die Baumart Robinie (Robinia pseudoacacia) angepflanzt und im Kurzumtriebverfahren bewirtschaftet. Es wurde untersucht, ob sich die Robinie positiv auf die Humusakkumulation im Boden auswirkt und welchen Einfluß die latente Nährstoffarmut (insbesondere im Hinblick auf Phosphor) des Substrates auf das Wuchspotential dieser Baumart ausübt. Die Ergebnisse zeigen, dass es unter Robinie innerhalb kurzer Zeit nach Flächenanlage zu einer Humus- bzw. Kohlenstoffakkumulation im Kippsubstrat kommt, worin ein Beitrag zur Erhöhung der Fruchtbarkeit des Standortes gesehen wird. Die durchschnittliche Zuwachsleistung der Robinie ist allerdings durch die geringe P Verfügbarkeit im Substrat deutlich eingeschränkt, wie durch eine versuchsweise P Düngung gezeigt werden konnte. Allerdings war die P-induzierte Wuchssteigerung von nur kurzer Dauer, da bereits eine Vegetationsperiode später der Düngeeffekt nicht mehr nachweisbar war

Effects of Drought Frequency on Growth Performance and Transpiration of Young Black Locust ( Robinia pseudoacacia

Black locust (Robinia pseudoacacia L.) is a drought-tolerant fast growing tree, which could be an alternative to the more common tree species used in short-rotation coppice on marginal land. The plasticity of black locust in the form of ecophysiological and morphological adaptations to drought is an important precondition for its successful growth in such areas. However, adaptation to drought stress is detrimental to primary production. Furthermore, the soil water availability condition of the initial stage of development may have an impact on the tree resilience. We aimed to investigate the effect of drought stress applied during the resprouting on the drought tolerance of the plant, by examining the black locust growth patterns. We exposed young trees in lysimeters to different cycles of drought. The drought memory affected the plant growth performance and its drought tolerance: the plants resprouting under drought conditions were more drought tolerant than the well-watered ones. Black locust tolerates drastic soil water availability variations without altering its water use efficiency (2.57 g L−1), evaluated under drought stress. Due to its constant water use efficiency and the high phenotypic plasticity, black locust could become an important species to be cultivated on marginal land

Blattstreu-Umsatz in Robinien-Kurzumtriebsplantagen auf Lausitzer Tagebau-Rekultivierungsflächen

Ein wichtiges Ziel der Flächenrekultivierung in der Lausitzer Braunkohlen-Tagebauregion ist die nachhaltige Bodenverbesserung durch Anreicherung von Humus in den sich auf den nährstoffarmen Kippsubstraten entwickelnden Böden. Mit Hilfe eines Streubeutel-Experiments wurde während der Vegetationsperiode 2010 die Abbaubarkeit von Laubstreu der Robinie (Robinia pseudoacacia L.) in vier unterschiedlich alten und verschieden bewirtschafteten Kurzumtriebsplantagen zur Biomasseproduktion auf Rekultivierungsflächen in der Region untersucht. Die Auswertung ergab, dass im Mittel nach einer Vegetationsperiode rund 40 % der Laubstreu abgebaut worden war, womit eine vergleichsweise gute Umsetzbarkeit der Robinien-Streu festgestellt werden konnte. Wird die vergleichsweise hohe Wuchsleistung auf den Rekultivierungsstandorten sowie der zusätzliche N-Eintrag durch die N2-fixierende Robinie berücksichtigt, kann demzufolge für Robinie ein nennenswertes Potential zur Bodenverbesserung auf den Rekultivierungsstandorten abgeleitet werden

Effect of nitrogen fertilizer and compost on photosynthesis and growth of Virginia fanpetals (Sida hermaphrodita Rusby)

Als mehrjährige Bioenergiepflanze kann Sida hermaphrodita eine wichtige Rolle für den Anbau auf marginalen Standorten in der nahen Zukunft spielen. In einem kon­trollierten Topfexperiment wurde der Einfluss von verschiedenen Kompostgehalten (10, 20, 30, 50%) und mineralischem Stickstoffdünger (100 kg N ha–1) auf Biomasse, Wuchshöhe und Kohlenstoffallokation während der Etablierungsphase untersucht. Weiterhin wurden ökophysiologische Parameter (Gaswechsel, Chlorophyllfluoreszenz, Chlorophyllgehalte) mit nicht-destruktiven Methoden bestimmt. Die Ergebnisse des Experimentes zeigen, dass sowohl die Stickstoffdüngung als auch die Kompostgabe positive Effekte für das Wachstumsverhalten hat. Während der Etablierungsphase erreichten die gedüngten Pflanzen eine mittlere Pflanzenhöhe von bis zu 127 cm (maximale Wuchshöhe 168 cm). Die Photosynthese wurde nicht durch die unterschiedlichen Behandlungen beeinflusst. Die mittlere CO2-Austauschrate variiert zwischen 5,8 und 9,9 μmol m–2 s–1 und die Elektronentransportrate zwischen 34,5 und 53,9 μmol m–2 s–1. Die Verwendung von Kompost und Stickstoff ist für eine bessere Biomasseproduktion von Sida in marginalen Böden möglich, auch wenn das Wachstum im ersten Jahr limitiert ist und es negative Rückwirkungen auf die Bestandesetablierung gibt.As a perennial bioenergy crop Sida hermaphrodita can play an important role on marginal lands in the near future. In a controlled pot experiments the influence of various proportions of compost (10, 20, 30, 50%) and nitrogen fertilizer (100 kg N ha–1) on biomass, plant height, and carbon allocation were investigated during the establishment phase. Furthermore, ecophysiological parameters (gas exchange, chlorophyll fluorescence, chlorophyll content,) were determined with non-destructive methods. The results of this experiment demonstrated that nitrogen fertilization and compost application has an overall positive effect on the overall growth performance. During the establishment phase, the fertilized plants reached a mean high of up to 127 cm (maximal plant height up to 168 cm). Photosynthesis was not influenced by the treatments and the mean net CO2-exchange rates varied between 5,8 and 9,9 μmol m–2 s–1 and the electron transport rate between 34,5 and 53,9 μmol m–2 s–1. The application of compost and nitrogen for a better biomass production of Sida on marginal soils is possible, however the growth is limited in the first year with negative effects on the establishment of larger crops