Gas emission from anaerobic decomposition of plant resources

Abstract

Aim The aim of this study was to quantify the emission rates of gases resulting from the anaerobic decomposition of different plant resources under conditions usually found in sediments of tropical aquatic systems and drained organic soils. Methods Incubations were prepared with green leaves, bark, twigs, plant litter, sugarcane stalks and leaves, soybean leaves, grasses, forest leaves and an aquatic macrophyte (Typha domingensis). Over 10 months, the daily volume of gas evolved from decay was measured and a kinetic model was used to describe the anaerobic mineralization. Results Using the mathematical model, it can be observed that the composition of the plant resources is heterogeneous. The temporal variation of the gas rates indicated that the mineralization of the labile fractions of detritus varied, on a carbon basis, from 16.2 (bark) to 100% (samples composed of leaves, grasses and sugar cane stalks). High gas emissions were observed during the mineralization of grasses, sugar cane stalks, leaves and plant litter, while low volumes of gases were measured during the mineralization of bark, twigs, forest leaves and T. domingensis, which are the most fibrous and recalcitrant resources (carbon content: 83.8, 78.2, 64.8 and 53.4%, respectively). The mineralization of labile carbon presented half-life values, which varied from 41 (twigs) to 295 days (grasses). Conclusions Considering the high amount of remaining recalcitrant fraction, the anaerobic decomposition of these plant resources showed a strong trend towards accumulating organic matter in flooded soils. Despite the higher temperatures found in the tropical environment, these environments represent a sink of particulate detritus due to its slow decomposition.

Decomposition Dynamics ofTypha angustifoliaunder Aerobic Conditions

“…11,23 The mass loss during this time is associated with the release of cytoplasmic fractions and hydrosoluble compounds that were present in the macrophyte. 24,25 The release of phosphorus during the initial decomposition period is linked to the loss of soluble phosphorus that had accumulated in plant tissue vacuoles.…”

A conceptual framework for sustainable waste management in small municipalities: the cases of Langebaan, South Africa and Swakopmund, Namibia

“…The interview questions were mostly open, leaving space for the researcher to probe further by asking follow-up questions. It facilitated two-way communication by allowing participants to respond with open-ended questions or statements for more in-depth information and understanding (Creswell 2013). Research questions were built around current municipal waste management policies, processes, procedures, and practices, and sustainable waste management and CE application in the two municipalities.…”

“…Generally, the importance of practising proper waste collection and disposal is to avoid detrimental environmental consequences and improve public well-being (Geetha and Rajalakshmi 2020 ). For example, anaerobic decomposition of organic waste produces greenhouse gases such as methane and carbon dioxide, which pose significant environmental hazards including climate change and global warming (Cunha-Santino et al 2016 ). By contrast, as previously highlighted, transitioning to sustainable waste management could have substantial positive environmental and socio-economic consequences, such as the creation of jobs in recycling industries (Wahba et al 2019 ).…”