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Aims: Management can largely influence the sustainability and functionality of forest plantations. However, the role of biogas-slurry and biochar application in supporting soil's multifunctionality during afforestation remains poorly understood. Methods: We conducted a six-year field experiment to examine the responses of soil ecosystem multifunctionality (EMF) to the application of biogas-slurry applied annually as four treatments, and a single initial application of four treatments of biochar in a new poplar plantation based on a reclaimed coastal area. The EMF was calculated as the standardized average of multiple soil surrogates of soil functions linked with C, N, and P cycles. Results: Both biogas-slurry and biochar had significantly positive effects on EMF and individual functions, with biogas-slurry having the strongest positive effect, thus promoting carbon stocks and nutrient availability. Furthermore, interactions between biochar and biogas-slurry produced a substantial synergistic effect on soil multifunctionality. The application of biogas-slurry significantly and directly increased the C, N, and P cycle multifunctionality (CCMF, NCMF, and PCMF, respectively). In contrast, a single application of biochar profoundly increased the CCMF but decreased the NCMF, thus requiring a trade-off of multiple elements of soil multifunctionality. Conclusions: We show that organic management has the potential to boost multiple ecosystem functions during afforestation. These findings further highlight the importance of rational fertilization strategies for long-term forest management. [ABSTRACT FROM AUTHOR]

Salinity is a global issue and Eucalyptus camaldulensis Dehnh. is one of the most planted agroforestry tree species on saline soils in Pakistan. Organic amendments are reported to ameliorate plant growth in saline sodic soils. This study was designed to examine the effects of different organic amendments on the growth of E. camaldulensis grown in saline soil. A pot experiment was performed and seedlings of E. camaldulensis were grown in soil having pH (8.5) and EC(e) 20.5dS/m. Four types of organic amendments were used: farmyard manure, poultry manure, slurry and biochar. The maximum plant total biomass (132.12 g), root length (24.67 cm) and shoot length (174.33 cm) were recorded in the plants grown in soils amended with farmyard manure. The minimum plant total biomass (36.05 g), root length (9.44 cm) and shoot length (68.0 cm) were found in plants without any amendment. Plants treated with farmyard manure and biochar showed the best results for chlorophyll contents, photosynthetic rate and stomatal conductance. Sodium contents in the shoots and roots of plants treated with organic amendments were decreased whereas potassium contents were increased. Maximum sodium contents were found in the shoot (5.70 mg/g DW) and root (7.71 mg/g DW) of un-amended plants, whereas, maximum potassium contents were in the shoots (7.81 mg/g DW) and roots 6.33 mg/g DW) of plants treated with biochar. Biochar was found to be best amendment to improve physicochemical characteristics of soil by improving organic matter (%) and saturation (%) as well as decreasing EC and SAR values of saline soils. Findings of this experiment suggested that organic amendments are useful in enhancing the early stage growth of E. camaldulensis in saline soils. [ABSTRACT FROM AUTHOR]

Land-management options for greenhouse gas removal (GGR) include afforestation or reforestation (AR), wetland restoration, soil carbon sequestration (SCS), biochar, terrestrial enhanced weathering (TEW), and bioenergy with carbon capture and storage (BECCS). We assess the opportunities and risks associated with these options through the lens of their potential impacts on ecosystem services (Nature's Contributions to People; NCPs) and the United Nations Sustainable Development Goals (SDGs). We find that all land-based GGR options contribute positively to at least some NCPs and SDGs. Wetland restoration and SCS almost exclusively deliver positive impacts. A few GGR options, such as afforestation, BECCS, and biochar potentially impact negatively some NCPs and SDGs, particularly when implemented at scale, largely through competition for land. For those that present risks or are least understood, more research is required, and demonstration projects need to proceed with caution. For options that present low risks and provide cobenefits, implementation can proceed more rapidly following no-regrets principles. [ABSTRACT FROM AUTHOR]

Negative emissions technologies (NETs) and their potential role in meeting emission targets is a rapidly growing and contentious area of climate change mitigation research. The literature ranges in scope from general reviews of NETs options to research and development through applied case studies. Within this field, a gap exists in the application of this growing body of research to the unique limitations and opportunities of a specific nation. Ireland is a small developed island nation in the EU with a unique emissions profile, as 32% of the total comes from agriculture due to the high number of cattle. In this study we aim to assess the potential capacity of terrestrial NETs options for Ireland and review the nation-specific context for their deployment. Despite the proportionally high representation of biochar and carbon capture and storage in the international NETs research, in an Irish context afforestation and bioenergy crops are much more established practices and could readily be considered in possible emission pathways that use NETs. Higher capacities were found for NETs options that are currently unavailable (direct air carbon capture and storage and bioenergy with carbon capture and storage), while options available to deploy at scale (afforestation, soil carbon management and biochar) have capacities limited by saturation of soil carbon stock and have higher risk of reversibility due to impermanence. Hence, while we estimate a reasonable technical capacity for NETs in Ireland, emission reduction remains the highest priority for feasibly meeting a Paris-aligned carbon quota for Ireland. [ABSTRACT FROM AUTHOR]

Reforestation of landscapes is being used as a method for tackling climate change through carbon sequestration and land restoration, as well as increasing biodiversity and improving the provision of ecosystem services. The success of reforestation activities can be reduced by adverse field conditions, including those that reduce germination and survival of plants. One method for improving success is biochar addition to soil, which is not only known to improve soil carbon sequestration, but is also known to improve growth, health, germination and survival of plants. In this study, biochar was applied to soil at rates of 0, 1, 3 and 6 t ha − 1 along with a direct-seed forest species mix at three sites in western Victoria, Australia. Changes in soil chemistry, including total carbon, and germination and survival of species were measured over an 18 month period. Biochar was found to significantly increase total carbon by up to 15.6% on soils low in carbon, as well as alter electrical conductivity, Colwell phosphorous and nitrate- and ammonium-nitrogen. Biochar also increased the number of species present, and stem counts of Eucalyptus species whilst decreasing stem counts of Acacia species. Biochar has the potential to positively benefit reforestation activities, but site specific and plant–soil–biochar responses require targeted research. [ABSTRACT FROM AUTHOR]

Abstract: The increasing demand of fossil fuels and decreasing light oil proven reserves lead to a future scenario of abundant coke production from the refinement of non-conventional fossil hydrocarbons. This paper highlights the possibility of using coke as an agrichar for preparing fertile soils resembling Amazonian terra preta. It is suggested that this alternative may contribute to both the capture of greenhouse gas by afforestation and the increase of rainfall by the albedo effect. It is proposed that the ideal agrichar must function as a store of nutrients in the form of graphene substituted NPK groups at the micropore molecular structure, providing habitat for plant friendly microorganism inside its macropores. The possibility of a sink effect connecting nutrient storage with microorganisms has also been proposed. A preliminary discussion on the possible coking procedures to improve the resulting agrichar efficacy, three options for large scale desert greening using agrichar as well as recommendations for further research are presented. [Copyright &y& Elsevier]

Abstract: Climate change will have serious effects on the planet and on its ecosystems. Currently, mitigation efforts are proving ineffectual in reducing anthropogenic CO2 emissions. Coral reefs are the most sensitive ecosystems on the planet to climate change, and here we review modelling a number of geoengineering options, and their potential influence on coral reefs. There are two categories of geoengineering, shortwave solar radiation management and longwave carbon dioxide removal. The first set of techniques only reduce some, but not all, effects of climate change, while possibly creating other problems. They also do not affect CO2 levels and therefore fail to address the wider effects of rising CO2, including ocean acidification, important for coral reefs. Solar radiation is important to coral growth and survival, and solar radiation management is not in general appropriate for this ecosystem. Longwave carbon dioxide removal techniques address the root cause of climate change, rising CO2 concentrations, they have relatively low uncertainties and risks. They are worthy of further research and potential implementation, particularly carbon capture and storage, biochar, and afforestation methods, alongside increased mitigation of atmospheric CO2 concentrations. [Copyright &y& Elsevier]