Pore architecture and particulate organic matter in soils under monoculture switchgrass and restored prairie in contrasting topography

Bioenergy cropping systems can substantially contribute to climate change mitigation. However, limited information is available on how they affect soil characteristics, including pores and particulate organic matter (POM), both essential components of the soil C cycle. The objective of this study was to determine effects of bioenergy systems and field topography on soil pore characteristics, POM, and POM decomposition under new plant growth. We collected intact soil cores from two systems: monoculture switchgrass (Panicum virgatum L.) and native prairie, at two contrasting topographical positions (depressions and slopes), planting half of the cores with switchgrass. Pore and POM characteristics were obtained using X-ray computed micro-tomography (μCT) (18.2 µm resolution) before and after new switchgrass growth. Diverse prairie vegetation led to higher soil C than switchgrass, with concomitantly higher volumes of 30–90 μm radius pores and greater solid-pore interface. Yet, that effect was present only in the coarse-textured soils on slopes and coincided with higher root biomass of prairie vegetation. Surprisingly, new switchgrass growth did not intensify decomposition of POM, but even somewhat decreased it in monoculture switchgrass as compared to non-planted controls. Our results suggest that topography can play a substantial role in regulating factors driving C sequestration in bioenergy systems.

De-Risking Wood-Based Bioenergy Development in Remote and Indigenous Communities in Canada

Remote and Indigenous communities in Canada have a unique opportunity to mobilize the vast amount of wood-based biomass to meet their energy needs, while supporting a local economy, and reducing greenhouse gas (GHG) emissions. This study realized in collaboration with five remote and Indigenous communities across Canada investigates the main barriers and potential solutions to developing stable and sustainable wood-based bioenergy systems. Our results highlight that despite the differences in available biomass and geographical context, these communities face common policy, economic, operational, cultural, social, and environmental risks and barriers to developing bioenergy. The communities identified and ranked the biggest barriers as follows; the high initial investment of bioenergy projects, the logistical and operational challenges of developing a sustainable wood supply chain in remote locations, and the limited opportunities for community leadership of bioenergy projects. Environmental risks have been ranked as the least important by all the communities, except for the communities in Manitoba, which ranked it as the second most important risk. However, all the communities agreed that climate change is the main environmental driver disturbing the wood-based bioenergy supply chain. To de-risk the wood-based bioenergy system, we suggest that stable and sustainable supply chains can be implemented by restoring community-based resources management supported by local knowledge and workforce. Using local knowledge can also help reduce the impacts caused by biomass harvesting on the ecosystem and avoid competition with traditional land uses. Including positive externalities to cost benefit analysis, when comparing bioenergy systems to existing energy installation, will likely make bioenergy projects more attractive for the community financially. Alternatively, supporting co-learning between partners and among communities can improve knowledge and innovation sharing.

Special Issue on “Bioenergy Systems, Material Management, and Sustainability”

The growing worldwide demand for energy and resources, combined with the stringent environmental challenges and regulations, means that the efficient, cost-effective, and sustainable use of energy and material sources, including bio-based, has become increasingly important [...]