Nitrous oxide emissions after incorporation of winter oilseed rape (Brassica napus L.) residues under two different tillage treatments

The aim of this study was to investigate the effect of crop residues from winter oilseed rape on N₂O emissions from a loamy soil and to determine the effect of different tillage practices on N₂O fluxes. We therefore conducted a field experiment in which crop residues of winter oilseed rape (Brassica napus L., OSR) were replaced with ¹⁵N labelled OSR residues. Nitrous oxide (N₂O) emissions and ¹⁵N abundance in the N₂O were determined for a period of 11 months after harvest of OSR and in the succeeding crop winter wheat (Triticum aestivum L.) cultivated on a Haplic Luvisol in South Germany. Measurements were carried out with the closed chamber method in a treatment with conventional tillage (CT) and in a treatment with reduced soil tillage (RT). In both tillage treatments we also determined N₂O fluxes in control plots where we completely removed the crop residues. High N₂O fluxes occurred in a short period just after OSR residue replacement in fall and after N‐fertilization to winter wheat in the following spring. Although N₂O emissions differed for distinct treatments and sub‐periods, cumulative N₂O emissions over the whole investigation period (299 days) ranged between 1.7 kg and 2.4 kg N₂O‐N ha^?1 with no significant treatment effects. More than half of the cumulative emissions occurred during the first eight weeks after OSR replacement, highlighting the importance of this post‐harvest period for annual N₂O budgets of OSR. The contribution of residue N to the N₂O emission was low and explained by the high C/N‐ratio fostering immobilization of mineral N. In total only 0.03% of the N₂O‐N emitted in the conventional tillage treatment and 0.06% in the reduced tillage treatment stemmed directly from the crop residues. The ¹⁵N recovery in the treatments with crop residues was 62.8% (CT) and 75.1% (RT) with more than 97% of the recovered ¹⁵N in the top soil. Despite our measurements did not cover an entire year, the low contribution of the OSR residues to the direct N₂O emissions shows, that the current IPCC tier 1 approach, which assumes an EF of 1%, strongly overestimated direct emissions from OSR crop residues. Furthermore, we could not observe any relationship between tillage and crop residues on N₂O emission, only during the winter period were N₂O emissions from reduced tillage significantly higher compared to conventional tillage. Annual N₂O emission from RT and CT did not differ.     

PAH biodegradation by telluric saprotrophic fungi isolated from aged PAH-contaminated soils in mineral medium and historically contaminated soil microcosms

Journal of Soils and Sediments - Remediation of contaminated soils is of high relevance considering losses of this limited resource in most countries through erosion or through destruction for...     

Untersuchungen über Rassenunterschiede in der Milchleistung beim Schwein I. Mitteilung: Methodik des maschinellen Milchentzuges und Milchmengenleistung

Inhalt: Die vorliegende Untersuchung stellt einen Beitrag zur Methodik des maschinellen Milchentzuges beim Schwein dar. Mittels einer eigens hierzu entwickelten Melkmaschine wurde die Milchleistung der in ihren Muttereigenschaften stark differierenden Rassen Pietráin (PI) und Deutsches Edelschwein (DE) ermittelt. Der Milchentzug erfolgte in 2-stündigen Kontrollabschnitten an den Laktationstagen 3, 7,14, 21 und 28. Bei DE kam es während der 4wöchigen Laktationsphase zu einer gleichmäβigen Steigerung der Milch-sekretion von 5,05 1 am 3. Tag auf 12,8 l am Tag 28. Die Sekretionsrate der Rasse PI folgte diesem Verlauf, quantitativ um 2 bis 3 l/d reduziert, bis zu einem Maximum am 14. Laktationstag. Danach sank sie wieder ab. Am Tag 28 betrug der Leistungsunterschied zwischen beiden Rassen über 5 l/Tag. Mit dieser überlegenen Milchsekretionsrate zogen die DE-Sauen 3 Ferkel/Wurf mehr aufals die PI. Auch nach der Standardisierung derFerkelzahl zu Untersuchungsbeginn auf n = 10 blieb die Direrenz zugunsten der Edelschweine signifikant erhalten. Über die Milchinhaltsstoffe und ihre Abhängigkeit von Rasse und Laktationstag sowie ihre Bedeutung für die Lebendmasseentwicklung der Ferkel wird in der II. Mitteilung berichtet. Contents: Investigations on breed differences in milk yield of swine. I. comittment: methodology of mechanical milking and milk yield. This paper deals with the methodology of mechanical milking of sows. By a milking machine, especially developed herefore, milk yields of the breeds Pietrain (PI) and German Large White (DE) which differ a lot in weaning performance, were investigated. Milk was taken in two-hourly control intervalls on the days 3,7,14,21 and 28 of lactation. During this period of 4 weeks, DE showed a continuous increase in milk yield from 5.05 l on day 3 to 12.8 l on day 28. Secretion rate of PI followed parallel with a quantitative decrease of 2 to 3 liters/day, till a maximum was reached on day 14. Then lactation rates decreased. The difference in yield performance between the two breeds was about 5 l on day 28. This superior milk performance of the DE-sows allowed them to wean 3 piglets per litter more than PI. The advantage of DE over PI stays even after standardization of the litter size on n = 10 piglets. Milk composition, its relation towards breed and lactation day and its meaning for the litter performance will be topic of the second comittment.     

Typing of Salmonella by DNA-microarrays

Microarrays (DNA-Chips) are miniaturized carriers on which many nucleic acid molecule probes such as oligonucleotides or PCR products are immobilized in a high density, and compactness. Homologue DNA hybridises with the immobilized complementary nucleic acid probes. This study gives after a short general introduction in the principle of DNA-microarrays an overview about published data on the field of typing of Salmonella by microarrays. An onset of a DNA-microarray developed by the National Reference Laboratory for Salmonella (NRL-Salm) will be introduced. By this new technique, it is possible to answer epidemiological questions as well as to find genes involved in certain biochemical processes, such as pathogenicity or resistance of salmonellae.     

Inhibition of acetyl-coenzyme a carboxylase by the novel grass-selective herbicide 3-(2,4-dichlorophenyl)-perhydroindolizine-2,4-dione

The novel herbicidal compound 3-(2,4-dichlorophenyl)-perhydroindolizine-2,4-dione which is active as a pre- and post-emergence grass-selective herbicide is a new type of inhibitor of plant acetyl-coenzyme A carboxylase (ACCase; E.C. 6.4.1.2). This has been demonstrated by in-vitro experiments using isolated corn enzyme. Besides an I₅₀ value of 4.7 μM under the assay conditions used, a mixed-type inhibitory activity on the enzyme is established. The compound is inactive on rat liver A CCase enzyme and shows decreased activity (pI₅₀ less than 3.0) on the spinach enzyme.     

Ring-trial results for the cultural detection of Salmonella in poultry faeces

The Directive 2003/99/EG of the European Parliament and of the Council on the monitoring of zoonoses and zoonotic agents demands a quality management (QM) system for the execution of its monitoring programmes. Consequently the National Salmonella Reference Laboratory of Germany performed two ring-trials in 2005 and 2006 on the microbiological detection of Salmonella from poultry feces among all participating laboratories in the Federal States. Salmonella detection was performed according to the EN ISO 6579:2002 standard method which was modified according to the recommendations of the Community Reference Laboratory for Salmonella in Bilthoven, The Netherlands. This method uses modified-semisolid Rappaport-Vassiliadis Agar as the only selective enrichment. In 2005 twenty-four and in 2006 twenty-two laboratories participated.They received eight identical samples of the contamination levels L0 (no Salmonella), L1 (11 and 16 cfu per 10 g faeces respectively) and L2 (292 and 418 cfu per 10 g faeces respectively). For both years the data of 20 laboratories could statistically be evaluated. The relative accuracy of the respected results increased from 88.8% in 2005 to 98% in 2006. This is as well reflected in the improved COR- and Kappa-Indices. Taken all together the data show, that the modified-semisolid Rappaport-Vassiliadis protocol is a sensitive, established method for the detection of Salmonella from poultry faeces.