Various studies have established that feedstock choice, pyrolysis temperature, and pyrolysis type influence final biochar physicochemical characteristics. However, overarching analyses of pre-biochar creation choices and correlations to biochar characteristics are severely lacking. Thus, the objective of this work was to help researchers, biochar-stakeholders, and practitioners make more well-informed choices in terms of how these three major parameters influence the final biochar product. Utilizing approximately 5400 peer-reviewed journal articles and over 50,800 individual data points, herein we elucidate the selections that influence final biochar physical and chemical properties, total nutrient content, and perhaps more importantly tools one can use to predict biochar’s nutrient availability. Based on the large dataset collected, it appears that pyrolysis type (fast or slow) plays a minor role in biochar physico- (inorganic) chemical characteristics; few differences were evident between production styles. Pyrolysis temperature, however, affects biochar’s longevity, with pyrolysis temperatures > 500 °C generally leading to longer-term (i.e., > 1000 years) half-lives. Greater pyrolysis temperatures also led to biochars containing greater overall C and specific surface area (SSA), which could promote soil physico-chemical improvements. However, based on the collected data, it appears that feedstock selection has the largest influence on biochar properties. Specific surface area is greatest in wood-based biochars, which in combination with pyrolysis temperature could likely promote greater changes in soil physical characteristics over other feedstock-based biochars. Crop- and other grass-based biochars appear to have cation exchange capacities greater than other biochars, which in combination with pyrolysis temperature could potentially lead to longer-term changes in soil nutrient retention. The collected data also suggest that one can reasonably predict the availability of various biochar nutrients (e.g., N, P, K, Ca, Mg, Fe, and Cu) based on feedstock choice and total nutrient content. Results can be used to create designer biochars to help solve environmental issues and supply a variety of plant-available nutrients for crop growth.

Bioenergy can produce at least 25% of the global energy demand to combat climate change through reducing emissions in the energy sector. However, information on the bioenergy production potential of woody species and their suitability for silviculture on various soils in the humid tropics is limited. This review aims to identify tree species suitable for bioenergy production under these conditions. Data were compiled from 241 publications and nine freely available databases to assess environmental and silvicultural information on tropical tree species. Energy outputs were derived from the estimated productivity of the reviewed species and ranged from 0.2 to 24.0 Mg biomass ha⁻¹ yr⁻¹, 0.1 to 9.0 Mg bio-oil ha⁻¹ yr⁻¹, and 0.2 to 20.0 Mg sugar ha⁻¹ yr⁻¹, equivalent to an energy yield between 2 and 444 GJ ha⁻¹ yr⁻¹. As such, these bioenergy yields are within the range reported for the lignocellulosic biomass of energy crops cultivated in Europe, the USA, and Brazil. Our review identified some high-yielding species (e.g., Dyera polyphylla (Miq.) Steenis, Metroxylon sagu (Rottb.), Pongamia pinnata (L.)) and leguminous species that could be beneficial in mixed stands (e.g., Elaeis oleifera (Kunth) and Pongamia pinnata) or are suitable species to grow on wet or re-wetted peatland (Dyera polyphylla). However, there are limitations to cultivate woody bioenergy species on wet peatland. Sustainable methods for managing and harvesting forests, particularly on wet or re-wetted peatland, need to be developed.

Our planet suffers from humankind’s impact on natural resources, biogeochemical cycles and ecosystems. Intensive modern agriculture with inappropriate inputs of fertilisers, pesticides and fossil fuel –based energy has increasingly added to human pressure on the environment. As a key element of our natural capital, soils are also under threat, despite being essential to provide food, feed, fibre and fuel for an increasing global population. Moreover, soils play a key role in carbon, water and energy cycles, highlighting their importance for biomass provision and the circular bioeconomy. Evidently, these new and complex challenges cannot be resolved effectively with existing knowledge and experience alone. These challenges require scientific research, interdisciplinary collaboration and networking to find context-specific and tailored solutions addressing societal issues of our time and facilitating the adoption of these solutions. The most effective approaches are based on the involvement of multiple actors from science, policy, economy, civil society and farming that have the same goal, work on the same societal issue, but have complementing backgrounds, expertise and perceptions. The European Joint Programme (EJP) SOIL is a European network of research institutes in the field of soil science and agricultural soil management that will provide science-based advice to practitioners and policymakers, at local, national and European level. The EJP SOIL aims to align and boost research, training and capacity building through joint programming activities co-funded by the European Commission and national research programs. This will reduce current fragmentation and help to find synergies in order to make a leapfrog in research on good agricultural soil management in three main areas: climate change mitigation and adaptation, production capacity in healthy food systems, and environmental sustainability. By joint programming, training and capacity building, EJP SOIL will also take into account the need for effective policy solutions, as well as the socio-economic conditions of all stakeholders in the agricultural value chain. Thus, a key focus of the EJP SOIL is to build and strengthen a framework for an integrated community of research groups working on related aspects of agricultural soil management. As part of this effort, EJP SOIL will co-construct with stakeholders a roadmap for agricultural soil research. To develop a structured roadmap, EJP SOIL works with a version of the knowledge management framework of Dalkir (2005). The EJP version uses four compartments: (i) Knowledge development, (ii) knowledge harmonisation, organisation and storage (iii) knowledge sharing and transfer, and (iv) knowledge application. The four segments are part of a cyclic process to enhance the development and use of knowledge on agricultural soils. Knowledge development comprises assessing new knowledge needs to achieve the expected impacts of EJP SOIL. Therefore, by involving multiple stakeholders, knowledge gaps across Europe will be identified to work towards the adoption of Climate-Smart Sustainable Agricultural Soil Management (CSSASM). Within the knowledge sharing and transfer compartment, the capacity of scientists, advisors, policy makers, farmers and other stakeholders will be strengthened. EJP SOIL will work to support networks and co-creation of new knowledge with stakeholder groups, stimulating innovation in CSSASM. The knowledge harmonization, organization and storage compartment of the knowledge framework ensures linkages with all stakeholders to guarantee data harmonization and standardization. The last compartment, application of knowledge, will be facilitated by creating better guidelines, awareness and capacity for Climate-Smart Sustainable Agricultural Soil Management adoption and by strengthening science-to-policy processes at EU and Member State level.