E-learning guideline for submission of QLIF publications to Organic Eprints

Following a workshop at the 3rd QLIF congress, a tutorial 5-min speakshow on submission of papers to Organic Eprints archive has been produce

Band-steaming reduces laborious hand-weeding in vegetables

Band-steaming is a new method that may reduce the need for hand-weeding in demanding row crops like carrot and drilled onion. Band-steaming only affects a soil volume equal to the intra-row area of the subsequent crop, and effectively kills the weed seeds in this soil volume. Side-effects on beneficial soil organisms are minimized as compared to current steaming technology, but still need to be assessed

Økologi-kongres sidst i maj

Danske og europæiske økologer samles den 30.-31. maj 2006 i Odense for at dele deres viden fra projekter om økologi

Nyt om forskning i økologisk jordbrug

Noter om: (1) Bioenergi og jordkvalitet; (2) Kontrollér dæktrykket og undgå pakning; (3) Markforsøg i billeder og videoklip; (4) Økologi begrænser kålfluepuppe

Landet rundt noter

Noter om: (1) Insekter bekæmpes af naturlige fjender; (2) Lupin begrænser ornelugt; (3) Norsk satsning på øko-grønt; (4) Ny centerleder i FØJO

Effektiv deling af økologisk viden

Webstedet Organic Eprints vinder frem som et effektivt redskab til deling af viden om økologisk jordbrug

Thermophilic Sulfate Reduction in Hydrothermal Sediment of Lake Tanganyika, East Africa

In environments with temperatures above 60 degrees C, thermophilic prokaryotes are the only metabolically active life-forms. By using the (SO42-)-S-35 tracer technique, we studied the activity of sulfate-reducing microorganisms (SRM) in hot sediment from a hydrothermal vent site in the northern part of freshwater Lake Tanganyika (East Africa). Incubation of slurry samples at 8 to 90 degrees C demonstrated meso- and thermophilic sulfate reduction with optimum temperatures of 34 to 45 degrees C and 56 to 65 degrees C, respectively, and with an upper temperature limit of 80 degrees C. Sulfate reduction was stimulated at all temperatures by the addition of short-chain fatty acids and benzoate or complex substrates (yeast extract and peptone). A time course experiment showed that linear thermophilic sulfate consumption occurred after a lag phase (12 h) and indicated the presence of a large population of SRM in the hydrothermal sediment. Thermophilic sulfate reduction had a pH optimum of about 7 and was completely inhibited at pH 8.8 to 9.2. SRM could be enriched from hydrothermal chimney and sediment samples at 60 and 75 degrees C. In lactate-grown enrichments, sulfide production occurred at up to 70 and 75 degrees C, with optima at 63 and 71 degrees C, respectively. Several sporulating thermophilic enrichments were morphologically similar to Desulfotomaculum spp. Dissimilatory sulfate reduction in the studied hydrothermal area of Lake Tanganyika apparently has an upper temperature limit of 80 degrees C

Økologi - Nyt om forskning

Noter om: (1) Økologisk forædling af hvedesorter; (2) Løsnet pløjesål med blandet effekt på udbytte; (3) Skadetærskler for kvik og tidsler; (4) Møde om økologisk vækst

Nutrient availability affects carbon turnover and microbial physiology differently in topsoil and subsoil under a temperate grassland

Increasing subsoil organic carbon inputs could potentially mitigate climate change by sequestering atmospheric CO2. Yet, microbial turnover and stabilization of labile carbon in subsoils are regulated by complex mechanisms including the availability of nitrogen (N), phosphorous (P), and sulfur (S). The present study mimicked labile organic carbon input using a versatile substrate (i.e. glucose) to address the interaction between carbon-induced mineralization, N-P-S availability, and microbial physiology in topsoil and subsoils from a temperate agricultural sandy loam soil. A factorial incubation study (42 days) showed that net losses of added carbon in topsoil were constant, whereas carbon losses in subsoils varied according to nutrient treatments. Glucose added to subsoil in combination with N was fully depleted, whereas glucose added alone or in combination with P and S was only partly depleted, and remarkably 59–92% of the added glucose was recovered after the incubation. This showed that N limitation largely controlled carbon turnover in the subsoil, which was also reflected by microbial processes where addition of glucose and N increased β-glucosidase activity, which was positively correlated to the maximum CO2 production rate during incubation. The importance of N limitation was substantiated by subsoil profiles of carbon source utilization, where microbial metabolic diversity was mainly related to the absence or presence of added N. Overall, the results documented that labile carbon turnover and microbial functions in a temperate agricultural subsoil was controlled to a large extent by N availability. Effects of glucoseinduced microbial activity on subsoil physical properties remained ambiguous due to apparent chemical effects of N (nitrate) on clay dispersibility

Recent results in the development of band steaming for intra-row weed control

The recent achievements with developing band-steaming techniques for intra-row weed control in vegetables are presente