Effect of lime-pelleting on the nodulation of lucerne (Medicago sativa L.) in an acid soil: A comparative study carried out in the field,in pots and in rhizotrons

The nodulation of lucerne was studied in soil (pH-H₂O 5.2) with seeds either inoculated with Rhizobium meliloti (R), or inoculated and pelleted with lime (RP). For comparison, experiments were done in the field and in two types of micro-cosmos: pots and rhizotrons. In the field experiments, lime-pelleting improved the establishment of seedlings and augmented the nitrogen yield of the first harvest. These positive responses in plant growth were the consequence of a better nodulation on the upper 10 mm of the seedling tap root. The number of seedlings carrying crown nodules increased from 18% (R) to 56% (RP) at 26 days after sowing.In both, pots and rhizotrons, lime-pelleting also increased crown nodulation: in pots from 32% (R) to 60% (RP), and in rhizotrons from 5% (R) to 90% (RP). Rhizotrons, made of plastic petri dishes, allowed for continuously following of early root developments and nodule formation. Crown nodulation could already be measured after 14 days. Based on these experiments, it was concluded (i) that crown nodulation is an adequate parameter to quantify the benefit of lime-pelleting, and (ii) that rhizotrons, because of the more pronounced effects and shorter incubation time, are more suitable to study the nodulation responses in the soil caused by the addition of rhizobia and lime.     

Maximizing farm-level uptake and diffusion of biological control innovations in today’s digital era

When anthropologists interviewed Honduran and Nepali smallholders in the mid-1990s, they were told that “Insects are a terrible mistake in God’s creation” and “There’s nothing that kills them, except for insecticides”. Even growers who maintained a close bond with nature were either entirely unaware of natural pest control, or expressed doubt about the actual value of these services on their farm. Farmers’ knowledge, beliefs and attitudes towards pests and natural enemies are of paramount importance to the practice of biological control, but are all too often disregarded. In this study, we conduct a retrospective analysis of the extent to which social science facets have been incorporated into biological control research over the past 25 years. Next, we critically examine various biological control forms, concepts and technologies using a ‘diffusion of innovations’ framework, and identify elements that hamper their diffusion and farm-level uptake. Lastly, we introduce effective observation-based learning strategies, such as farmer field schools to promote biological control, and list how those participatory approaches can be further enriched with information and communication technologies (ICT). Although biological control scientists have made substantial technological progress and generate nearly 1000 papers annually, only a fraction (1.4%) of those address social science or technology transfer aspects. To ease obstacles to enhanced farmer learning about biological control, we describe ways to communicate biological control concepts and technologies for four divergent agricultural knowledge systems (as identified within a matrix built around ‘cultural importance’ and ‘ease of observation’). Furthermore, we describe how biological control innovations suffer a number of notable shortcomings that hamper their farm-level adoption and subsequent diffusion, and point at ways to remediate those by tactical communication campaigns or customized, (ICT-based) adult education programs. Amongst others, we outline how video, smart phones, or tablets can be used to convey key ecological concepts and biocontrol technologies, and facilitate social learning. In today’s digital era, cross-disciplinary science and deliberate multi-stakeholder engagement will provide biocontrol advocates the necessary means to bolster farmer adoption rates, counter-act surging insecticide use, and restore public trust in one of nature’s prime services.     

Controlled supply of trace amounts of oxygen in laboratory scale fermentations

A detailed study of anaerobic yeast fermentations requires controlled addition of minor amounts of oxygen to the fermentor. A method for supplying small-scale fermentations with millimolar amounts of oxygen is described. The controlled addition is accomplished by diffusion of oxygen through silicone tubing carrying nitrogen to the fermentor. Sulfite values of the fermentation system are given for different gas velocities and lengths of silicone tubing. Two experiments are outlined in which this technique is applied and the possible energy yield from oxydative phosphorylation is discussed.     

Synthesis and spectral characteristics of some unusual fatty esters of podophyllotoxin

Five fatty ester derivatives of podophyllotoxin have been prepared by reacting the corresponding fatty acids with the hydroxy group of podophyllotoxin in the presence of dimethylaminopyridine and N,N-dicyclohexylcarbodiimide. The fatty acids incorporated are: 9,12-epoxy-9,11-octadecadienoic acid, octadec-11E-en-9-ynoic acid, 11,12-E-epoxy-octadec-9-ynoic acid, octadeca-9Z,11E-dienoic acid and 9,10-dibromooctadecanoic acid. The average yield of esterification was >95% and the structures of the products were confirmed by a combination of nuclear magnetic resonance spectroscopic and mass spectrometric analyses.     

Regionalized phosphorus fate factors for freshwater eutrophication in Bahia,Brazil: an analysis of spatial and temporal variability

The International Journal of Life Cycle Assessment - Fate factors, for freshwater eutrophication, represent the route of a limiting-nutrient, phosphorus or nitrogen, and their degradation in the...