Niedermoore im nordostdeutschen tiefland Einführung

Die Auswirkungen von vier Kippsubstratvarianten des Lausitzer Braunkohlereviers (quartäre, tertiäre asche‐ bzw. kalkmeliorierte sowie quartäre Kippsubstrate über tertiärem Untergrund) auf die Stofffrachten der Sickerwässer aus einer 300 cm mächtigen Bodendecke wurden in den ersten zwei Jahren eines von 1992 bis 1996 laufenden Großlysimeterversuches geprüft. Im Unterschied zu den fast Trinkwasserqualität erreichenden Perkolaten quartärer Kippsubstrate, wiesen die Sickerwässer aus tertiären Substraten vor allem im ersten Versuchsjahr extrem hohe Schadstoffkonzentrationen auf, die bei Ni, Zn, Cr, As und Cd weit über den Grenzwerten für Trinkwasser lagen. Im zweiten Jahr nahmen die Schadstoffkonzentrationen zwar ab (z.B. Zn, As um 56%), lagen aber dennoch deutlich über den Grenzwerten.

Im Vergleich zur Kalkmelioration bewirkte die Aschemelioration der tertiären Kippsubstrate signifikant niedrigere Schwermetall‐, Arsen‐ und Stickstoffausträge sowie im ersten Versuchsjahr z.T. signifikant niedrigere Spezieskonzentrationen.

Der erwartete positive Einfluß der quartären Deckschicht aus Sand über tertiärem Untergrund konnte bisher nicht nachgewiesen werden. Bezogen auf die Schichtmächtigkeit der eingefüllten tertiären Kippsubstrate wurden vor allem im zweiten Jahr nach Abklingen der durch die Bodenumlagerung (Belüftung) verursachten stärkeren Oxidation der Sulfide bei dieser Variante vergleichsweise größere Schadstoffmengen (As, Zn, Ni, Pb) freigesetzt und ausgewaschen. Gleichzeitig nahmen die N_org‐Austräge zu, die wie die hohen NH₄ ⁺‐Frachten auf eine verstärkte oxidative Desaminierung im tertiären Untergrund hinweisen.     

Ein beitrag zur charakterisierung der Bodenveränderungen durch erosion im Jungmoränengebiet

Die Wassererosion, initiiert durch anthropogene Eingriffe durch Bodennutzung, führte zu veränderten Bodenprozessen und einer starken Bodenprofilverkürzung an konvexen und einer Sedimentakkumulation an konkaven Hangbereichen. Die Abtragsbilanz kann durch eine Bodenneubildung nicht annähernd ausgeglichen werden. Der Grad der Veränderung kann durch den Vergleich mit Waldböden der gleichen Genese und Morphologie im Landschaftsausschnitt bestimmt werden, da diese kaum eine Differenzierung zwischen konvexen und konkaven Hangbereichen aufweisen. Der Veränderungsgrad kann durch die Korngrößenzusammensetzung, die Entkalkungstiefe sowie den Gehalt an organischer Bodensubstanz eingeschätzt werden. Die Gehalte an C_org zeigen den Grad der erosionsbedingten Bodendegradierung sehr deutlich. Die Zusammensetzung der leicht abbaubaren OBS differiert viel weniger und wird offenbar durch die aktuelle Nutzung überprägt. An einer weiteren Aufklärung der Veränderung der organischen Bodensubstanz an erosionsbeeinflussten Hängen wird geforscht, weil dieser Parameter als ein wichtiger Indikator für den Zustand und die Degradierung der Böden angesehen werden kann.     

Nitrogen fertilization does not affect micronutrient uptake in grain maize (Zea mays L.)

Abstract

Due to continuous single nitrogen fertilization, we hypothesized a built-up deficiency of micronutrients in crops that would limit plant growth and crop quality. In 2-year field experiments using urea-N fertilized grain maize (Zea mays L.), hybrid KWS 2376 at 0, 120 and 240 kg N ha^?1 crop uptake of Zn, Mn, Cu and Fe was studied at DC 32, DC 61 and in the grain harvested. Micronutrient contents at DC 32 stage – 1st node (aboveground phytomass) and DC 61 – flowering (ear leaf) were all at levels indicative of adequate micronutrient supply to the crop. At both sampling occasions the Fe:Zn and Fe:Mn ratios were adequate implying that Fe did not inhibit the uptake of Zn and Mn. The application of nitrogen increased the Fe content at the 1st sampling in both years; in the second year the same was also the case for the Zn content. Nitrogen nutrition increased the contents of Mn and Fe at the 2nd sampling only in year 2; in the other treatments no changes were observed in the micronutrient contents. Micronutrient correlations in the grain were discovered between Zn and Mn contents and between Fe and Mn contents. In the second year the highest N-rate significantly increased the Fe and Zn content of the grain compared with the lower rates of nitrogen fertilization. Grain yields were not affected by the rate of nitrogen and ranged between 13.65 and 14.34 t ha^?1 (1st year) and between 13.68 and 14.18 t ha^?1 (2nd year). Nitrogen fertilization did not reduce the content of micronutrients in the plant or grain of maize. It is evident that the continuous single use of N fertilization so far has not resulted in a micronutrient deficiency of the plants limiting the nutrient density of the grain or reducing its quality.     

Microbial response of soils with organic and conventional management history to the cultivation of Bacillus thuringiensis (Bt)-maize under climate chamber conditions

An experiment was carried out in a climate chamber to analyse if Bt-maize may cause particular changes in soils with different levels of microbial biomass and activity due to long-term management history. Among the soils selected, the ones managed organically for 30 years exhibited twice the microbial biomass and 2.6 times the dehydrogenase activity (DHA) of the soil from a field with long-term conventional maize monoculture. Soils were cultivated twice in a row with Bt-maize, its near-isogenic line and a conventional breeding line. We tested the hypotheses that (a) soil microbial biomass and activity are affected by the cultivation of Bt-maize and that (b) the influence of Bt-maize depends on the level of soil microbial biomass and activity. Shoot and root yield and shoot C-content of Bt-maize were higher than the ones of the near-isogenic line. DHA under Bt-maize was 6 % higher, and the metabolic quotient for CO₂ (qCO₂) was 9 % lower than under its near-isogenic line, giving some support to hypothesis (a). No significant interactions of the soils and the varieties used were found in this study, thus hypothesis (b) was not confirmed, and soils with different microbial biomass and activity appear to react in a similar way to the cultivation of Bt-maize.     

Soil micromorphological and physical properties after application of composts with polyethylene and biocomponent-derived polymers added during composting

Composts are considered to be one of the best soil amendments. However, the effects of composts with added polymeric materials on soil physical,hydraulic, and micromorphological properties have not been widely discussed. Changes in soil physical properties influence the numerous services that soils provide. We studied the impacts of composts with the addition of three different polymers(F1–F3) produced from polyethylene and thermoplastic corn starch on the physical, hydraulic, and micromorphological properties of two soils, a Cambic Phaeozem and a Luvic Phaeozem. Applying composts with polymers had limited or no significant effect on soil bulk density and porosity, but increased the field water capacity by 18%–82% and 3%–6% and the plant-available water content by 15%–23% and 4%–17% for the Cambic Phaeozem and Luvic Phaeozem, respectively. The application of composts with polymers had a greater effect on the Cambic Phaeozem than on the Luvic Phaeozem. It was suggested that the use of modified composts led to changes in soil physical properties and micromorphological features and this effect was dependent on the compost application rate. Composts made with the addition of composite synthetic and natural material-derived polymers during composting were found to be a composite mixture that can be successfully used in agriculture.     

Genes responsible for coronatine synthesis in <Emphasis Type="Italic">Pseudomonas syringae</Emphasis> present in the genome of soft rot bacteria

Primers for the PCR amplification of homologous genes encoding polyketide coronafacic acid and coronafacic ligase in the cells of Pectobacterium atrosepticum SCRI1043 (BX950851) were developed to study the presence of these genes in the genome of Pectobacterium sp. and Dickeya sp. Coronafacic ligase catalyses the formation of coronatine from polyketide coronafacic acid and coronamic acid. Coronatine is a toxin produced by Pseudomonas syringae and is one of the major virulence factors in this bacterium. This study using several strains of P. atrosepticum, P. carotovorum subsp. carotovorum and Dickeya sp. isolated in different countries, indicated that all strains of P. atrosepticum possess genes coding coronafacic acid (cfa gene cluster) and coronafacic ligase (cfl). However, these genes were present only in the genome of five out of 50 tested P. carotovorum subsp. carotovorum strains and two out of 34 strains of Dickeya sp. tested. The PCR products homologous to the sequence of cfa7 and cfl gene fragments were sequenced in order to check the level of homology between genes of P. atrosepticum, P. carotovorum subsp. carotovorum and Dickeya sp. The sequences of the gene fragments amplified from all P. atrosepticum strains were almost identical (100% and 99.97%, respectively). The homology of the sequences obtained for P. atrosepticum and sequences of five P. carotovorum subsp. carotovorum and two Dickeya sp. was lower, between 89.69% to 95.00% for the cfl gene fragment, and about 94% for the cfa7 gene fragment.     

Multi-systemic Trauma in a Ferret

A 5-year old, neutered, male, domestic sable ferret presented 24 hours after escaping outside and sustaining unknown trauma. Physical examination findings included tachycardia, tachypnea, and hind limb paresis in a laterally recumbent patient. Radiographs, laboratory evaluation, and abdominocentesis revealed the presence of hemoperitoneum, blunt hepatic trauma, pneumothorax, and a small abdominal hernia. The ferret was treated with resuscitative fluids, thoracocentesis, abdominal counterpressure, and blood transfusion. This is the first case report of multi-systemic trauma in a ferret. The ferret made a complete recovery and was discharged to the referring veterinarian three days after presentation. (Vet. Emerg. Crit. Care, 10:13–18, 2000)     

Leukocyte numbers and intestinal mucosal morphometrics in horses with no clinical intestinal disease

Healthy horses and other animals have large numbers of resident leukocytes in the intestinal wall, but there is scant information regarding which and how many leukocytes are normally present in the equine intestinal wall. Our aim was to provide a reference range of leukocytes in the intestinal mucosal and submucosal propria of normal horses. We included in our study intestinal tissues from 22 Thoroughbred racehorses with no clinical intestinal disease, which had been euthanized because of catastrophic musculoskeletal injuries. Neutrophils, lymphocytes, eosinophils, macrophages, and plasma cells were counted in 5 random 17,600-µm² areas of villus lamina propria of the duodenum, jejunum, and ileum, and deep lamina propria of the duodenum, jejunum, ileum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and small colon. Other features investigated in the same intestinal segments included villus height and width (small intestine), presence of ciliated protozoa, Paneth cells number, subcryptal leukocyte layers (number of leukocyte layers between the bottom of the crypts and the muscularis mucosae), and submucosal leukocytes. Lymphocytes were the most numerous cells in all segments analyzed, followed by plasma cells, eosinophils, macrophages, and neutrophils. Eosinophil numbers were significantly higher in both lamina propria and submucosa of the large intestine than in the small intestine. The duodenum had shorter and thinner villi than either jejunum or ileum. The data provided from our study will be useful for diagnosticians examining inflammatory processes in the intestinal tract of horses.