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Biochar is the carbon-rich organic matter that remains after heating biomass under the minimization of oxygen during a process called pyrolysis. There are a number of reasons why biochar systems may be particularly relevant in developing-country contexts. This report offers a review of what is known about opportunities and risks of biochar systems. Its aim is to provide a state-of-the-art overview of current knowledge regarding biochar science. In that sense the report also offers a reconciling view on different scientific opinions about biochar providing an overall account that shows the various perspectives of its science and application. This includes soil and agricultural impacts of biochar, climate change impacts, social impacts, and competing uses of biomass. The report aims to contextualize the current scientific knowledge in order to put it at use to address the development climate change nexus, including social and environmental sustainability. The report is organized as follows: chapter one offers some introductory comments and notes the increasing interest in biochar both from a scientific and practitioner's point of view; chapter two gives further background on biochar, describing its characteristics and outlining the way in which biochar systems function. Chapter three considers the opportunities and risks of biochar systems. Based on the results of the surveys undertaken, chapter four presents a typology of biochar systems emerging in practice, particularly in the developing world. Life-cycle assessments of the net climate change impact and the net economic profitability of three biochar systems with data collected from relatively advanced biochar projects were conducted and are presented in chapter five. Chapter six investigates various aspects of technology adoption, including barriers to implementing promising systems, focusing on economics, carbon market access, and sociocultural barriers. Finally, the status of knowledge regarding biochar systems is interpreted in chapter seven to determine potential implications for future involvement in biochar research, policy, and project formulation.

Biofuels offer new opportunities for African countries. They can contribute to economic growth, employment, and rural incomes. They can become an important export for some countries and provide low-cost fuel for others. There is also a potentially large demand for biofuels to meet the rapidly growing need for local fuel. Abundant natural resources and low-cost labor make producing biofuel feedstock's a viable alternative to traditional crops; and the preferential access available to most African countries to protected markets in industrial countries provides unique export opportunities. Biofuels also bring challenges and risks, including potential land-use conflicts, environmental risks, and heightened concerns about food security. This book examines the potential of African countries to produce biofuels for export or domestic consumption and looks at the policy framework needed. It is part of the effort by the World Bank's Africa region to examine critical issues that affect the region and to recommend policies that effectively address these issues while providing an enabling environment for the private sector. The book is intended to inform policy makers and the larger development community of the global and domestic market opportunities facing biofuel producers, as well as the challenges of producing biofuels, in the Africa region.

These report overviews recent developments in the consumption and production of bioenergy. It examines the main issues and possible economic implications of these developments and assesses their potential impact on land use and the environment, especially with respect to forests. The report examines both solid biomass and liquid biofuels, identifying opportunities and challenges at the regional and country levels. The development of bioenergy presents both opportunities and challenges for economic development and the environment. It is likely to have significant impacts on the forest sector, directly, through the use of wood for energy production, and indirectly, as a result of changes in land use. The impact of bioenergy on poverty alleviation in developing countries will depend on the opportunities for agricultural development, including income and employment generation, the potential to increase poor peoples' access to improved types of bioenergy; and the effects on energy and food prices. Five main messages emerge from this report: solid biomass will continue to be a principal source of energy; developments in bioenergy will have major implications for land use; tradeoffs, including those related to poverty, equity, and the environment, must be evaluated when choosing a bioenergy system; there is considerable potential for making greater use of forestry and timber waste as a bioenergy feedstock; and the climate benefits of bioenergy development are uncertain and highly location and feedstock specific.

Cyanobacteria represent a globally important biomass because they are responsible for a substantial proportion of primary production in the hydrosphere. Arthrospira platensis is a fast-growing halophilic cyanobacterium capable of accumulating glycogen and has the potential to serve as a feedstock in the fermentative production of third-generation biofuels. Accordingly, enhancing cyanobacterial glycogen production is a promising biofuel production strategy. However, the regulatory mechanism of glycogen metabolism in cyanobacteria is poorly understood. The aim of the present study was to determine the metabolic flux of glycogen biosynthesis using a dynamic metabolomic approach. Time-course profiling of widely targeted cyanobacterial metabolic intermediates demonstrated a global metabolic reprogramming that involves transient increases in the levels of some amino acids during the glycogen production phase induced by nitrate depletion. Also, in vivo labelling with NaH13CO3 enabled direct measurement of metabolic intermediate turnover in A. platensis, revealing that under conditions of nitrate depletion glycogen is biosynthesized with carbon derived from amino acids released from proteins via gluconeogenesis. This dynamic metabolic profiling approach provided conclusive evidence of temporal alterations in the metabolic profile in cyanobacterial cells.

For more than a billion years, seaweeds have been a segment of marine primary productivity this fact must be contemplated while considering emerging conceptual frameworks such as the “blue economy”. This sector not only has the potential to provide renewable feedstock but its cultivation and processing ticks an important box for sustainable development. Seaweed cultivation in India is gaining momentum and great attention is being given to developing the infrastructure. A flagship program ‘Pradhan Mantri Matsya Sampada Yojana (PMMSY)’ has provided adequate budgetary allocation to achieve a production of 11.2 Mt (fresh) feedstock. However, the scheme seems to focus only on material benefits (product development) and the ecosystem services, especially regulatory services have seldom been taken into consideration. Thus, the present article tries to address the estimation of potential regulatory ecosystem services [capture carbon, uptake nutrients and heavy metals (Cr, Co, Cd)] met through Kappaphycus alvarezii farming, at the Pan-India level. The estimates were made for both tube net and raft cultivation methods separately. The farm cover was estimated to be around 700,000 ha supporting approximately 780,000 farmers for tube net, while it was 56,000 ha supporting ~ 1.25 million farmers for raft cultivation. A total number of tube nets that would be put to use would be 140 million and 56 million in the case of rafts. Once the target is achieved India would have gained the ability to annually capture approximately 600,000 t of carbon, 22,000 t of nitrogen, and 2000 t of phosphorous and absorb more than 1000 t of heavy metals cumulatively. Nevertheless, a monetary valuation of ecosystem services is needed to arrive at rational decisions by policy-makers and resource managers.

Water and energy flux densities of co‐located cellulosic feedstocks, switchgrass (Panicum virgatum L.) and high biomass sorghum (Sorghum bicolor L. Moench), were measured using the eddy covariance technique during the 2012 and 2013 growing seasons to quantify and compare evapotranspiration (ET) and ecosystem water use efficiency (EWUE). Peak growing season ET from the switchgrass field was approximately 6 mm d−1 in both years; whereas, the sorghum ET reached 6.7 in 2012 and 4.8 mm d−1 in 2013. While both species showed similar water use patterns during the active growing period, seasonal cumulative ET was higher in switchgrass due to a longer growing season. Monthly ET integrals were strongly correlated with monthly integrals of gross primary production (GPP) and net ecosystem production (NEP) for both species, suggesting a strong linkage between C gain and water loss over the season. Different methods of EWUE estimations yielded different EWUE values. The ratio of seasonal sums of GPP to ET yielded EWUE of 9.41 to 11.32 and 8.98 to 9.17 g CO2 mm−1 ET in switchgrass and sorghum, respectively. The ratio of seasonal sums of NEP to ET was 2.75 to 2.81 and 2.06 to 2.18 g CO2 mm−1 ET in switchgrass and sorghum, respectively. Slightly larger EWUE in switchgrass than sorghum shows that the switchgrass was more efficient than the sorghum on using water to gain C. Results suggest that larger seasonal C uptake by switchgrass was enough to offset its higher water use due to the longer growing season. Eddy covariance technique can be used to assess bioenergy crops ecosystem water use efficiency. Swithcgrass has higher ET than sorghum due to longer growing season. Greater seasonal carbon uptake by switchgrass than sorghum was enough to offset higher water use.

The southern Great Plains of the USA has great potential to produce biofuel feedstock while minimizing the dual stresses of woody plant encroachment and climate change. Switchgrass (Panicum virgatum) cultivation, woody biomass captured during removal of the encroaching eastern redcedar (Juniperus virginiana) to restore grasslands and thinning of the native oak forest can provide an integrated source of feedstock and improve ecosystem services. In north‐central Oklahoma, we quantified productivity and ecosystem water use of switchgrass stands and degraded ecosystems encroached by eastern redcedar and compared these to native oak forest and tallgrass prairie ecosystems. We measured aboveground net primary productivity (ANPP) using allometric equations (trees) and clip plots (herbaceous), and evapotranspiration (ET) using a water balance approach from gauged watersheds, and calculated water use efficiency (WUE = ANPP/ET) from 2016 to 2019. Among vegetation cover types, ANPP averaged 5.1, 5.4, 6.0, and 7.8 Mg ha−1 year−1 for the prairie, oak, eastern redcedar, and switchgrass watersheds and was significantly greater for switchgrass in 2018 and 2019 (2 and 3 years post establishment) when it reached 8.6 Mg ha−1 year−1. Averaged across 2017–2019, ET was significantly greater in the forested watersheds than the grassland watersheds (1022 mm year−1 for eastern redcedar, 1025 mm year−1 for oak, 874 mm year−1 for prairie, and 828 mm year−1 for switchgrass). The mean WUE was significantly greater (9.47 kg ha−1 mm−1) for switchgrass than for the prairie, eastern redcedar, and oak cover types (6.03, 6.02, and 5.31 kg ha−1 mm−1). Switchgrass offered benefits of greater ANPP, less ET, and greater WUE. Our findings indicate that an integrated biofuel feedstock system that includes converting eastern redcedar encroached areas to switchgrass and thinning the oak forest can increase productivity, increase runoff to streams, and improve ecosystem services. Woody plant encroachment into grasslands is a global issue that has negative consequences on many ecosystem services. We asked whether feedstock productivity and water yield can be improved by harvesting unwanted woody biomass and converting to switchgrass. We measured and compared the productivity, water yield, and water use efficiency (WUE) of adjacent prairie, oak forest, eastern redcedar woodland, and switchgrass watersheds. Aboveground productivity and WUE of switchgrass was greater than the other ecosystem types such that including switchgrass into an integrated feedstock production system can increase biomass production and water yield while reversing some negative impacts of woody plant encroachment.

Background Cellulase enzymes have been reported to contribute with a significant share of the total costs and greenhouse gas emissions of lignocellulosic ethanol production today. A potential future alternative to purchasing enzymes from an off-site manufacturer is to integrate enzyme and ethanol production, using microorganisms and part of the lignocellulosic material as feedstock for enzymes. This study modelled two such integrated process designs for ethanol from logging residues from spruce production, and compared it to an off-site case based on existing data regarding purchased enzymes. Greenhouse gas emissions and primary energy balances were studied in a life-cycle assessment, and cost performance in a techno-economic analysis. Results The base case scenario suggests that greenhouse gas emissions per MJ of ethanol could be significantly lower in the integrated cases than in the off-site case. However, the difference between the integrated and off-site cases is reduced with alternative assumptions regarding enzyme dosage and the environmental impact of the purchased enzymes. The comparison of primary energy balances did not show any significant difference between the cases. The minimum ethanol selling price, to reach break-even costs, was from 0.568 to 0.622 EUR L-1 for the integrated cases, as compared to 0.581 EUR L-1 for the off-site case. Conclusions An integrated process design could reduce greenhouse gas emissions from lignocellulose-based ethanol production, and the cost of an integrated process could be comparable to purchasing enzymes produced off-site. This study focused on the environmental and economic assessment of an integrated process, and in order to strengthen the comparison to the off-site case, more detailed and updated data regarding industrial off-site enzyme production are especially important.

Background and aim Biochar application to soil is widely claimed to increase plant productivity. However, the underlying mechanisms are still not conclusively described. Here, we aim to elucidate these mechanisms using stable isotope probing. Methods We conducted two experiments with uniquely double-labelled (¹⁵N and ¹³C) biochar and its feedstock (residue), applied separately at 15 Mg ha⁻¹. Both experiments contained three treatments: biochar amendment (Biochar), unpyrolysed residue amendment (Residue) and a no addition control (Control). Experiment I was a 119 day pot experiment seeded with Lolium perenne. Experiment II was a 71 day incubation experiment without plants in which CO₂ and N₂O fluxes were measured. Results Both Biochar and Residue significantly increased aboveground productivity compared to Control (140% and 160%, respectively). Initial N immobilisation was stimulated in Residue, whereas not in Biochar. ¹³C–CO₂ analysis confirmed that biochar was significantly more recalcitrant than residue. ¹⁵N analysis showed that 2% and 0.3% of grass N was derived from the amended material in Residue and Biochar, respectively. Conclusions Our results suggest that biochar-induced yield increases derive from a combination of reduced N immobilization and a moderate N fertilization effect. Although in the short term biochar might offer benefits compared to residue incorporation, it is unlikely that biochar yield gains will be sustainable for the decades to centuries that biochar C can be expected to reside in soil.

Sugarcane (complex hybrids of Saccharum spp., C4 plant) croplands provide cane stalk feedstock for sugar and biofuel (ethanol) production. It is critical for us to analyze the phenology and gross primary production (GPP) of sugarcane croplands, which would help us to better understand and monitor the sugarcane growing condition and the carbon cycle. In this study, we combined the data from two sugarcane EC flux tower sites in Brazil and the USA, images from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, and data-driven models to study the phenology and GPP of sugarcane croplands. The seasonal dynamics of climate, vegetation indices from MODIS images, and GPP from two sugarcane flux tower sites (GPPEC) reveal the temporal consistency in sugarcane phenology (crop calendar: green-up dates and harvesting dates) as estimated by the vegetation indices and GPPEC data. The Land Surface Water Index (LSWI) is shown to be useful to delineate the phenology of sugarcane croplands. The relationship between the sugarcane GPPEC and the Enhanced Vegetation Index (EVI) is stronger than the relationship between the GPPEC and the Normalized Difference Vegetation Index (NDVI). We ran the Vegetation Photosynthesis Model (VPM), which uses the light use efficiency (LUE) concept and is driven by climate data and MODIS images, to estimate the daily GPP at the two sugarcane sites (GPPVPM). The seasonal dynamics of the GPPVPM and GPPEC at the two sites agreed reasonably well with each other, which indicates that VPM is a powerful tool for estimating the GPP of sugarcane croplands in Brazil and the USA. This study clearly highlights the potential of combining eddy covariance technology, satellite-based remote sensing technology, and data-driven models for better understanding and monitoring the phenology and GPP of sugarcane croplands under different climate and management practices.