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AbstractChina is under pressure to improve its agricultural productivity to keep up with the demands of a growing population with increasingly resource‐intensive diets. This productivity improvement must occur against a backdrop of carbon intensity reduction targets, and a highly fragmented, nutrient‐inefficient farming system. Moreover, the Chinese government increasingly recognizes the need to rationalize the management of the 800 million tonnes of agricultural crop straw that China produces each year, up to 40% of which is burned in‐field as a waste. Biochar produced from these residues and applied to land could contribute to China's agricultural productivity, resource use efficiency and carbon reduction goals. However competing uses for China's straw residues are rapidly emerging, particularly from bioenergy generation. Therefore it is important to understand the relative economic viability and carbon abatement potential of directing agricultural residues to biochar rather than bioenergy. Using cost‐benefit analysis (CBA) and life‐cycle analysis (LCA), this paper therefore compares the economic viability and carbon abatement potential of biochar production via pyrolysis, with that of bioenergy production via briquetting and gasification. Straw reincorporation and in‐field straw burning are used as baseline scenarios. We find that briquetting straw for heat energy is the most cost‐effective carbon abatement technology, requiring a subsidy of $7 MgCO2e−1 abated. However China's current bioelectricity subsidy scheme makes gasification (NPV $12.6 million) more financially attractive for investors than both briquetting (NPV $7.34 million), and pyrolysis ($−1.84 million). The direct carbon abatement potential of pyrolysis (1.06 MgCO2e per odt straw) is also lower than that of briquetting (1.35 MgCO2e per odt straw) and gasification (1.16 MgCO2e per odt straw). However indirect carbon abatement processes arising from biochar application could significantly improve the carbon abatement potential of the pyrolysis scenario. Likewise, increasing the agronomic value of biochar is essential for the pyrolysis scenario to compete as an economically viable, cost‐effective mitigation technology.

Understanding the relationship between climate and crop productivity is a key component of projections of future food production, and hence assessments of food security. Climate models and crop yield datasets have errors, but the effects of these errors on regional scale crop models is not well categorized and understood. In this study we compare the effect of synthetic errors in temperature and precipitation observations on the hindcast skill of a process-based crop model and a statistical crop model. We find that errors in temperature data have a significantly stronger influence on both models than errors in precipitation. We also identify key differences in the responses of these models to different types of input data error. Statistical and process-based model responses differ depending on whether synthetic errors are overestimates or underestimates. We also investigate the impact of crop yield calibration data on model skill for both models, using datasets of yield at three different spatial scales. Whilst important for both models, the statistical model is more strongly influenced by crop yield scale than the process-based crop model. However, our results question the value of high resolution yield data for improving the skill of crop models; we find a focus on accuracy to be more likely to be valuable. For both crop models, and for all three spatial scales of yield calibration data, we found that model skill is greatest where growing area is above 10-15 %. Thus information on area harvested would appear to be a priority for data collection efforts. These results are important for three reasons. First, understanding how different crop models rely on different characteristics of temperature, precipitation and crop yield data allows us to match the model type to the available data. Second, we can prioritize where improvements in climate and crop yield data should be directed. Third, as better climate and crop yield data becomes available, we can predict how crop model skill should improve.

AbstractVineyard pruning is a potential lignocellulosic feedstock for bioethanol production from agricultural woody residues, due to its high sugar content and ready availability in whole Europe. Ethanol production from lignocellulosic biomass requires a pretreatment step and then enzymatic hydrolysis process to release sugars for fermentation to ethanol. In this work, alkaline pretreatment with NaOH on vineyard residues was investigated on laboratory scale. The raw material was firstly characterized in order to determine cellulose, hemicellulose and lignin content, using the standard laboratory analytical procedures for biomass analysis provided by the National Renewable Energy Laboratory (NREL). Then, based on Response Surface Methodology tool (RSM), a Box-Behnken model was chosen to define a design of experiments (DoE) in terms of the three independent variables that influence the process: the NaOH concentration, the reaction time and the temperature of the pretreatment process. According to the design, 15 samples of raw material were submitted to alkaline pretreatment and subsequent enzymatic hydrolysis and the glucose yield from whole process was calculated. The statistical optimization was carried out with Minitab 17 software, in order to determine the best operative pretreatment condition by maximizing the glucose yield from enzymatic hydrolysis.Results show that the best glucose yield was obtained at the highest sodium hydroxide concentration and temperature of the reaction; this condition allowed to achieve very significant glucose yield thanks to lignin removal performed with the pretreatment.

Since the 1970s but with greater intensity in the 1980s, strong, social, economic, and cultural transformations have led to the post-Fordist or post-productivist countryside determining what researchers identify as “rural restructuring” [...]

From the comparison of regulations and/or standards for the organic, conventional and/or integrated citrus production method and a voluntary certification, it emerges that farms certified with voluntary non-regulated certification systems, such as the IFA FV GLOBALG.A.P, are obliged to take into account the highest number of aspects, reported in a more complete register, than the organic ones. Moreover, this is also supported by a continuous-time planned process of revision and updating of the applicable versions of the standard. The environmental impact of the food production, the safety aspects of food products, as well as the health, ethics, and safety aspects of workers, are largely considered and inspected in the GLOBALG.A.P., while the organic system, despite the IFOAM suggestions and indications, is only considered partially. This means that, from a practical point of view, the organic product can be considered “clean and safe”, but not more environmentally friendly than the GLOBALG.A.P. products.

Gallus domesticus is one of the world’s most consumed animals, with a significant presence in all parts of the planet. Chicken oil appears to be a credible raw material in the context of alternative energy research. This study focuses on a literature review to highlight the chicken’s energy potential and the application of energy recovery from local slaughterhouse-based Gallus gallus domesticus greasy residues and it is proposed to make biodiesel from the fatty residues of Gallus gallus domesticus. The transesterification reaction takes place at 60°C. Methanol is used in a 1 : 6 oil-to-alcohol mass ratio. Catalysis is carried out with 1% (m/m) potassium hydroxide (KOH). The accepted reaction time under light agitation is 120 minutes. The reaction yield is estimated to be 85.6%, and the biodiesel produced is characterized. The postcharacterization values are consistent with the EN14214 biodiesel standard. Gas chromatography coupled with mass spectrometry reveals the intrinsic composition of the acids derived from the developed biodiesel methyl esters. The latter reveals a predominance of oleic acids with a value of 29.47% and palmitic acids with a value of 29.21%. The viscosity of greasy residues appeared to be relatively high at 69.32 mm/s. The low calorific value is 38775.363 KJ/Kg and the cetane index is 50. It has been observed that, for 1000 g of fat waste, it is possible to extract by cooking 507.807 g of oil, or an extraction yield of 51%. Fatty chicken residues from tropical market areas can be used as a raw material for biofuel development.

Identifying local energy sources and devising a circular economy could improve self-sufficiency in many Pacific Islands. On the islands with significant agriculture, the residue from the cultivation of plants has promising energy potential. The waste stream is another potential source of energy that otherwise should undergo proper treatment. Additionally, cold-storage capacity improves the preservation of crops and increases the agricultural exports of these islands. This study proposes a combined cooling and power (CCP) system driven by biomass from agriculture residue and waste streams as fuel for different districts in Tonga. The units supply a fraction of the districts’ electricity demand and provide sufficient cold-storage capacity to preserve the prospective yield of a fraction of fallow lands. The technical and economic performance of the CCP units was analysed for different fractions of electricity demand and fallow land exploitation in each district during a year of operation. The results show that the optimum combination of the CCP units supplies 38% of the total electricity demand of Tonga and prevents the annual consumption of 7.4 million litres of diesel and emission of 20 kilotonnes of CO2. In addition, it provides 3700 m2 of cold-storage area, which is sufficient for preserving the prospective yield of the exploitation of 27% of the total fallow land of Tonga. Annual export revenue of about AU$10 million is expected from such a cold-storage capacity for Tongan farmers. Furthermore, the units consume 10,000 tonnes of annual waste, significantly reducing waste management costs. This study presents an example of a comprehensive circular-economy solution for a remote island state that improves its socioeconomic and environmental condition by supplying the community’s local needs from its available and abundant resources under a viable business model. The solution presented in this study can be adapted to many island communities with significant agriculture in the economy and crucial energy and cooling needs.