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Institute
BTU
There is a growing global need to produce more energy and reducing greenhouse gas emissions. One possible source of renewable energy in parts of Europe is the use of crop for bioenergy production. Currently, maize dominates the biogas production. For a diversified production of substrates alternative crops needs to be evaluated for their sustainable utilization and ecological integration into agro-systems. The new bioenergy plants IGNISCUM Candy and IGNISCUM Basic are cultivars of the Sakhalin Knotweed (Fallopia sachalinensis, Fam. Polygonaceae), which are characterized by a high annual biomass production. Information on the crop production of this species is rare. Hence, understanding plant response to the combinations of water and nutrients availability is crucial for the development of sustainable plant production. In greenhouse experiments we investigate the interrelations between nutrient supply, biomass production, and plant ecophysiology. For the determination of yield-transpiration relations at whole plant level we used a wick lysimeter system, which allows us to study plant growth under controlled water regimes and to calculate the plant transpiration. The irrigation is supplied by an automatic drip irrigation system and computer-controlled in relation to the volumetric soil water content. Four different water treatments associated to the SWC range from well-watered to drought stressed plants. The influence of plant sizes on plant water use was investigated under different nitrogen supply. The fertilizer applied is calcium ammonium nitrate (N) and the rates for the four treatments are 0, 50, 100, 150 kg N/ha at the beginning of the growing season. Plant transpiration is calculated on the basis of water input, storage and drainage in weekly intervals. The cumulative transpiration of the plants during the growing season is between 49 L (drought stressed) and 141 L (well-watered) per plant, respectively. We calculated a transpiration coefficient of 525 Liters per kg dry biomass.
Soils of former Manufactured Gas Plants (MGPs) are often contaminated with iron-cyanide (Fe-CN) complexes that originate from gas purification process. Cyanide is a potentially toxic substance and its presence in soil and groundwater may cause risk for human health as well as for the environment. MGPs were commonly built on the city suburban areas, which have spread ever since. Nowadays, these sites are typically located in inner cities, causing environmental thread, due to the leaching of pollutants. More recently, columns and batch experiments have been used to study fate and mobility of contaminants is soil. The release of iron-cyanide complexes under unsaturated flow conditions was evaluated with eight columns of 30 cm length and a diameter of 5,4 cm. Cyanide concentrations in the collected leachates were measured with Flow Injection Analysis (FIA). Additionally pH, electrical conductivity (EC) and various ion concentrations were determined. In order to compare the release of Fe-CN complexes in saturated conditions a batch experiment was conducted, where in defined time intervals, 1 ml of the extract water phase was analyzed for CN concentration. Study revealed an analogous trend of cyanide release in both experiments indicating primarily the release of formerly dissolved phase (hexacyanoferrates) followed by continual dissolution of ferric ferrocyanide. We conclude that batch experiments, conducted prior to column analysis, can serve as preliminary prediction of the water soluble cyanide fraction under unsaturated conditions.
Relationships between substrate, surface characteristics, and vegetation in an initial ecosystem
(2013)
We investigated surface and vegetation dynamics in the artificial initial ecosystem “Chicken Creek” (Lusatia, Germany) in the years 2006–2011 across a wide spectrum of empirical data. We scrutinized three overarching hypotheses concerning (1) the relations between initial geomorphological and substrate characteristics with surface structure and terrain properties, (2) the effects of the latter on the occurrence of grouped plant species, and (3) vegetation density effects on terrain surface change. Our data comprise and conflate annual vegetation monitoring results, biennial terrestrial laser scans (starting in 2008), annual groundwater levels, and initially measured soil characteristics. The empirical evidence mostly confirms the hypotheses,
revealing statistically significant relations for several goal variables: (1) the surface structure properties, local rill density, local relief energy and terrain surface height change; (2) the cover of different plant groups (annual, herbaceous, grass-like, woody, Fabaceae), and local vegetation
height; and (3) terrain surface height change showed significant time-dependent relations with a variable that proxies local plant biomass. Additionally, period specific effects (like a calendar-year optimum effect for the occurrence of Fabaceae) were proven. Further and beyond the hypotheses, our findings on the spatiotemporal dynamics during the system’s early development grasp processes which generally mark the transition from a geo-hydro-system towards a bio-geo-hydro system (weakening geomorphology effects on substrate surface dynamics, while vegetation effects intensify with time), where pure geomorphology or substrate feedbacks are changing into vegetation–substrate feedback processes.