Renate Sonnleitner

Effects of straw, vegetable oil and whey on physical and microbiological properties of a chernozem

Abstract A soil microcosm study was carried out to compare the effects of straw, vegetable oil or whey additions on physical and microbiological properties of a chernozem after 18 weeks of incubation. The application rates of the different organic materials were based on the addition of carbon at a concentration equivalent to 1% of soil dry mass. Straw, vegetable oil and whey additions to soil increased dry aggregate size distribution during incubation. All organic treatments had significantly higher mean weight diameter (MWD) of dry aggregates than the untreated control. The ability of whey, straw and oil to increase MWD did not differ significantly. Only straw addition significantly increased soil maximum water-holding capacity after 126 days of incubation. In comparison with the untreated control, straw tended to reduce the resistance of aggregates to abrasion, while addition of whey and vegetable oil seemed to have a positive effect on this property. Aggregates of organic matter amended soil materials had higher resistance to the dispersive action of water than those of the untreated control. Whey and straw additions sustained higher soil biomass-C contents and C mic / C org ratios than vegetable oil. Biomass development was most favored by whey addition. Fungal contributions to biomass-C dominated over bacterial contributions in whey and straw-amended soil. The opposite was observed for the oil treatment. Increases in MWD of dry aggregates seem to be related to the synthesis of biomass and soil binding metabolites in whey and straw-treated soil. Among the organic treatments, oil-amended soil had the highest respiratory activity and the lowest biomass content. Stabilizing agents derived from the microbial metabolism using oily substrate are discussed.

Mobilization of Metals from Pristine Mineral Soil by Nitrifying and Sulfur-Oxidizing Bacteria – The Leaching Potential of Indigenous Culture Enrichments

Indigenous chemolithotrophic nitrifying and sulfur-oxidizing culture enrichments mobilized metals from pristine mineral soil under conditions of ammonium or thiosulfate supplementation in a laboratory experiment carried out over a period of 40 days. The average mineralogical composition of the mineral soil was quartz (62%), feldspar (20%), muscovite (6%), chlorite (2%), hornblende (2%), dolomite (4%), and calcium carbonate (4%). The leaching efficiency of the nitrifying enrichment was calcium (27%), magnesium (15%), zinc (5.4%), manganese (0.6%), and cobalt (1.4%) after 40 days of incubation. In case of sulfur-oxidizing enrichment, leaching efficiency was calcium (56%), magnesium (36%), iron (0.8%), zinc (12%), manganese (2.1%), and cobalt (12%). The impact of these organisms on pristine mineral soil could be important in understanding primary colonization and the early stages of soil formation.

Microbial Mobilization of Major and Trace Elements from Catchment Rock Samples of a High Mountain Lake in the European Alps

Abstract At a high mountain lake in catchments of mica schist and gneiss rock in the European Alps, substantial increases in solute concentrations of sulfate, magnesium, calcium, silica, manganese, and nickel were observed over the past two decades. We hypothesized that microbial interactions with rock in the catchment of the lake might play an important role. We studied the chemolithotrophic activities resulting in the production of metal mobilizing metabolites (mineral acids). The potential of nitrifying and sulfur-oxidizing cultures derived from rock to mobilize elements from this rock when augmented with ammonium and thiosulfate was investigated in a 35 day laboratory study. Bacterial species prevailing in the indigenous nitrifying and sulfur-oxidizing mixed cultures were determined by 16S rRNA gene sequence based analysis. The average mineralogical composition of the rock sample was quartz (50%), feldspar (27%), muscovite (15%), chlorite (6%), and dolomite (2%). The increase of each soluble element in the presence of cultures relative to the conditions without microbes was related to the total element in the rock sample (leaching efficiency in percent). After 35 days, leaching efficiency was 7% (Ca), 2.4% (Mg), and 6.3% (Mn) in the presence of the nitrifying culture. In the presence of the sulfur-oxidizing culture, leaching efficiency was 13% (Ca), 5.7% (Mg), 5.4% (Mn), 1.3% (Zn), 0.2% (Fe), and 0.1% (Al). The results suggest that under conditions of abundant substrate availability, chemolithotrophic activity on catchment rock can contribute to the increase in soluble Ca, Mg, and Mn in lake water.

Monitoring of changes in physical and microbiological properties of a Chernozem amended with different organic substrates

A soil microcosm study was made to monitor changes in soil physical and microbiological properties of a Chernozem during a period of up to 126 or 252 days following the addition of whey, straw or vegetable oil. In the whey treatment soil maximum water-holding capacity (MWHC) had decreased after seven and 28 days of incubation. At both dates, the differences to the untreated control were significant. Straw was able to increase MWHC of soil during incubation and after 42 and 126 days values differed significantly from those of the control. Compared with the control, whey, oil and straw treatments had higher meanweight diameter of dry aggregates. The differences were significant after seven, 28 and 126 days with whey, after 42, 126 and 252 days with oil, and after 126 days with straw. The sensitivity of dry aggregates to abrasion (SAA), representing a negative index of dry aggregate stability, was lower in the whey treatment than in the control after three and seven days incubation. In the later phase of incubation, whey tended to increase SAA. A trend to increase SAA also was observed with straw and after 126 days a significantly higher SAA for the straw than for the oil treatment was determined. This trend still was to observe after 252 days incubation. An increase in SAA observed for the oil treatment after 42 days was followed by a decrease till the end of incubation. Aggregates of organic treatments were more resistant to the dispersive effect of water than those of the control. Microbial biomass-C contents were high in the whey treatment, ranging between 1931 and 754 μg g−1 soil dry mass during incubation. With whey, fungal contributions to biomass-C increased from 40.5% after three to 76.5% after 126 days incubation. Addition of straw or oil stimulated biomass synthesis less than whey. High fungal contributions to biomass-C, approx. 70%, were sustained by straw during incubation. With oil, fungal contributions were 20.5% after three, 76% after 42 and less than 20% after 126 and 252 days incubation. Fungal contributions to biomass-C correlated positively with SAA. High sensitivity of the fungal biomass to mechanical stress is discussed as a cause for the low dry aggregate stability of soils amended with organic substrates encouraging fungal biomass development.

Chemolithotrophic Metal Mobilization from Dolomite

The potential of indigenous chemolithotrophic bacteria to mobilize metals from dolomite in the presence of added ammonium or thiosulfate was studied in a laboratory experiment over a period of 35 days. The rock sample was collected in the Dolomites (Alps, Europe). The average mineralogical composition of the sample was dolomite (89%) and calcite (11%). After 35 days, mobilization of total metal in the rock sample amounted to 3.4% (Ca), 8.5% (Mg), 1% (Al), and 0.9% (Mn) in the presence of a nitrifying culture. In the presence of a sulfur-oxidizing culture, mobilization of total magnesium in the rock sample amounted to 34%.The results contribute to our understanding of interactions between atmospheric deposition of energy substrates, bacterial activity and metal mobilization in Alpine areas.

Mikroorganismen und Abbau organischer Fremdstoffe

Seit Jahren werden weltweit Untersuchungen zur Moglichkeit der mikrobiellen Transformation organischer Fremdstoffe unternommen. Diese Bemuhungen zeigten, das eine Vielzahl von Mikroorganismen in der Lage ist, solche Verbindungen unter Laborbedingungen und in Flussigkultur entweder zu mineralisieren oder cometabolisch zu transformieren.

Schwefel- und stickstoffhaltige anorganische Luftschadstoffe

In Mitteleuropa uberschritten Ende der achtziger Jahre bei den Luftschadstoffen die anthropogenen Emissionen die naturlichen etwa um den Faktor 10 (Ulrich 1987). Im Zeitraum 1980–1992 gingen die Schwefeldioxidemissionen in Europa um 39% und in Nordamerika um 17% zuruck (Rodhe et al. 1995). Im Vergleich zur vorindustriellen Zeit ist die Schwefeldeposition in Teilen dieser Regionen jedoch noch immer um den Faktor 10 erhoht. Trotz der Rucklaufigkeit der S02-Emissionen in Europa und Nordamerika konnte fur die Konzentration von H+-Ionen im Niederschlag kein entsprechender Ruckgang verzeichnet werden. Als Ursache dafur wird der gleichzeitig mogliche Ruckgang der Konzentrationen an basischen Kationen (vor allem Ca) diskutiert. Die NOx-Emissionen zeigen keinen abnehmenden Trend, wenngleich sich diese in Europa und Nordamerika auf ein gleichbleibendes Niveau einpendeln. Zunehmend konnen in anderen Regionen der Erde, wie in Teilen Ost- und Sudasiens, in Sudafrika und Sudamerika, rasche Zunahmen der S02-, NOx- und NH3-Emis-sionen achgewiesen werden.

Sanierung organisch kontaminierter Standorte

Die durch anthropogene Aktivitaten in die Umwelt freigesetzten Stoffe und anfallenden Abfalle veranderten sich in Laufe der Industrialisierung, der Intensivierung der Landwirtschaft und eines veranderten Siedlungs-und Konsumverhaltens sowohl in qualitativer als auch in quantitativer Hinsicht.

Potentielle Düngemittel — Industrie-, Gewerbe- und Siedlungsabfälle

Die Ruckfuhrung von in landwirtschaftlichen, hauslichen, gewerblichen und industriellen Abfallen gebundenen Nahrstoffen in den Kreislauf der Stoffe ist ein Anliegen der auf Nachhaltigkeit ausgerichteten Form des Wirtschaftens. Das Sammeln und Kompostieren von Abfallen aus Haushalt, Industrie und Gewerbe stellt einen wertvollen Beitrag zum Abfallmanagement und zur Aufrechterhaltung geschlossener Nahrstoffkreislaufe dar. In einer auf Nachhaltigkeit ausgerichteten Wirtschaft kommt den Boden sowohl die Funktion als Nahrungs- und Rohstofflieferanten als auch als Senken fur organische Abfalle zur Schliesung von Stoffkreislaufen zu. Durch die landwirtschaftliche Nutzung von Abfallen konnen Stoffstrome in die Atmosphare, welche bei Nutzung anderer Entsorgungsmoglichkeiten verstarkt auftreten, reduziert werden.

Geschichte und Perspektiven der Bodenmikrobiologie und -enzymatik

Die Bodenmikrobiologie beschaftigt sich mit der Untersuchung von im Boden lebenden Mikroorganismen und deren Aktivitaten. Die vorwiegenden Untersuchungsobjekte der Mikrobiologie sind Bakterien, Pilze und Viren. Der Begriff Mikroorganismen zielt sinngemas auf samtliche Organismen von sehr geringer Korpergrose und relativ geringer morphologischer Differenzierung ab. Solche kleinen Organismen, deren Untersuchung besonderer Arbeitstechniken, allem voran der Mikroskopie bedarf, werden auch im Pflanzen- und Tierreich gefunden.