The terrestrial vegetation is a source of UV radiation-induced aerobic methane (CH4 ) release to the atmosphere. Hitherto pectin, a plant structural component, has been considered as the most likely precursor for this CH4 release. However, most of the leaf pectin is situated below the surface wax layer, and UV transmittance of the cuticle differs among plant species. In some species, the cuticle effectively absorbs and/or reflects UV radiation. Thus, pectin may not necessarily contribute substantially to the UV radiation-induced CH4 emission measured at surface level in all species. Here, we investigated the potential of the leaf surface wax itself as a source of UV radiation-induced leaf aerobic CH4 formation. Isolated leaf surface wax emitted CH4 at substantial rates in response to UV radiation. This discovery has implications for how the phenomenon should be scaled to global levels. In relation to this, we demonstrated that the UV radiation-induced CH4 emission is independent of leaf area index above unity. Further, we observed that the presence of O2 in the atmosphere was necessary for achieving the highest rates of CH4 emission. Methane formation from leaf surface wax is supposedly a two-step process initiated by a photolytic rearrangement reaction of the major component followed by an α-cleavage of the generated ketone.

Reuse of phosphorus (P) from waste streams used for bioenergy conversion is desirable to reduce dependence on nonrenewable P resources. Two different ash materials from low-temperature biomass gasification of wheat straw and sewage sludge, respectively, were investigated with regard to their P bioavailability. A set of pot experiments with spring barley was carried out to compare the ash P fertiliser value with mineral P fertiliser and the sewage sludge feedstock. An indirect radioactive labelling approach with 33 P was used to determine the amount of P taken up from the fertiliser materials. Depending on the application rate, straw gasification ash produced a fertiliser response comparable to mineral P. However, P uptake from the ash was generally less than uptake from equivalent amounts of mineral P, and the calculated relative effectiveness was 44% after 6 weeks of plant growth. In contrast, the P fertiliser value of Fe-rich sewage sludge after low-temperature gasification was practically zero. These results suggest that ash from low-temperature gasification could be developed into alternative P fertilisers; however, as the P bioavailability depends greatly on the feedstock used, a greater emphasis on feedstock composition is required.

PurposeThe field study aimed at exploring how capacities are influenced by external factors in the context of community-based disaster risk reduction (CBDRR).Design/methodology/approachThe field study was conducted in a small rural area called Lapsibot in Lamjung district in Nepal. The article is based on a fieldwork conducted in April 2018. The different tools of data collection were inspired by the vulnerability and capacity assessment approach with a focus on various aspects of vulnerabilities and capacities with regard to disaster risk reduction (DRR) in Lapsibot.FindingsThe paper highlights that communities, in fact, need enhanced and extended capacities, not only existing inherent capacities, which are usually the main subject of capacity development in rural communities.Originality/valueWhile there is absolutely no question of strong capacities at the community level, this paper appeals for a more in-depth investigation of an extended notion of capacities, where the effects of the rapid changes and increasing impact of the outside world are taken into consideration.