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Two studies conducted in Guadeloupe (West Indies) and Réunion (Indian Ocean) islands were designed to investigate the benefits of producing sugarcane as an energy crop and to assess the influence of agroclimatic factors on energy efficiency, respectively. In this context, it is essential to know the low heating value of the dry above-ground biomass (LHVd, MJ/kg) and its energy yield (EY, MJ/m2) in order to select the best varieties and set up a payment method for growers. Eighteen Poaceae (sugarcane and Erianthus) cultivars were compared under wet tropical environmental conditions in Guadeloupe. Three sugarcane cultivars were studied in four contrasting environments in Réunion. The partition sampling and biomass measurement procedures were identical at both locations. Low heating value (LHV) predictions were achieved using near-infrared reflectance spectroscopy (NIRS) after specific calibration (Guadeloupe), or arithmetically after lignocellulosic compound prediction (Réunion). In both studies, LHV variability was very low and slightly dependent on the site, cultivar and above-ground biomass components (millable stalks and tops, and green and dead leaves). Considering the overall dry above-ground biomass (DAB, kg/m2), the LHVd was calculated by averaging 159 samples (mean 16.65 MJ/kg) in Guadeloupe and 315 samples (mean 16.45 MJ/kg) for Réunion. An excellent linear relationship between the DAB and its EY, regardless of cultivar, age and environment, was found (n = 474 and R² = 0.99). Sugarcane energy content assessment could thus be simplified by measuring the DAB, while enabling development of a faster method of payment for growers based on the DAB measurement and the correlation between DAB and EY. Finally, the findings of this study should allow growers to rapidly determine the commercial value of their sugarcane crops, and also enable purchasers to assess the amount of recoverable energy. (Résumé d'auteur)

Thermokinetics of Biochar production.

Escalating energy costs are an increasing concern for South Asian farmers growing rice and wheat in rotation. Millions of people in the IGP (Indo-Gangetic Plains) depend on this cropping system for food and income security. CT (conservation tillage) practices, including mechanical BP (bed planting), PTOS (power-tiller operated seeding), and ST (strip tillage), are advocated by donors and development organizations as profitable, high yielding, and energy-efficient alternatives to TT (traditional tillage). However, most studies on the EUE (energy input use efficiency) of CT originate from researcher-controlled and on-station experiments. Comparatively little information is available on the EUE of CT practices as farmers apply them in their own fields, and under their own management decisions. This research responds to this gap, and analyzes EUE of each of these three CT options, compared to TT, by surveying 328 rice-wheat farmers in north-western Bangladesh. Concentrating on wheat production, we employed a non-parametric benchmarking technique involving slack-based measures of technical efficiency, along with a fractional regression model to identify and compute the wasteful use of energy. PTOS achieved the highest EUE score (0.92), followed closely by BP and ST (both 0.91), whereas TT (0.68) was significantly (p <0.001) different and lower than the CT practices.

About 25 million tons of food go wasted or lost in Iran which has socio-economic and environmental consequences for both the country and the households. The main objective of this research is to develop a model to examine the relationship between FCM components and the amount of FW of households in Tehran city, with a focus on urban women. By means of a structural model, this study provides a novel approach to exploring relationships between the food-related behavior of urban households and waste control (n = 1197). Besides, this study is the first attempt to quantify food waste in Iran at the household level. According to the adopted self-reporting procedure, in Tehran, every consumer wastes about 27.6 kg of edible food annually. It is found that households with better food consumption management (FCM (have a lower level of food waste. Moreover, the results have proved that other determinants such as demographic factors, economic power, information use, ability, and motivation have direct and indirect significant effects on FCM as well as on the amount of food waste generation. The findings suggest that the above-mentioned determinants are crucial and should be considered when developing a strategically sustainable food waste prevention plan.

The energy transition in agriculture must be accompanied by agronomic practices that shift production towards organic regimes. Among the energy consuming processes that today find resistance in organic conversion there is certainly the removal of weeds from crops, that is mainly carried out through herbicides. This analysis evaluates the economic and environmental implications that the introduction of innovative thermal weeding systems, powered by biomass gasification, can have in the substitution of traditional chemical and mechanical weeding technologies. The comparison is carried out through a combination of cost–benefit analysis, environmental analysis and sensitivity analysis applied to the case study of vineyard management in northern Italy. The results show that the biomass-powered weeding system is economically feasible when it can benefit from economic incentives that reward organic production. In all cases, biomass-powered weeding system provides for a reduction in equivalent CO2 emissions which reaches −75% in the case of replacement of glyphosate-based chemical weeding methods. The analysis points out that gasification-powered weeding process can also achieve carbon neutrality through the co-production of biochar, which should lead policy makers to support this practice under the environmental objectives at national and European level.

Abstract Cutting costs in farms is the main concern for several stakeholders, specifically for farmers. Reducing energy costs allows for, at the very least, two relevant outcomes, one concerning increases in the net farm income and the other relating to the environment and the promotion of more sustainable farming and rural development. In turn, the agricultural sector may itself be a relevant source of renewable and clean energies. Considering these motivations, this research/study has intended to explore the concept of agricultural energy, highlighting the main insights from literature, and to stress the relationships between this concept and relevant farming indicators. The findings obtained may provide interesting support for the several related stakeholders, namely, policymakers, farmers and researchers. To achieve these objectives, literature available on scientific platforms was explored and statistical relationships were established, through econometric approaches (allowing for spatial effects), between structural characteristics from farms in the European Union. The findings reveal that the several instruments within the Common Agricultural Policy (CAP) should further address the relationships between financial support and sustainability. For example, it could be interesting to index the direct payments from the 1st CAP Pillar with farm indicators that consider dimensions related with the efficiency and savings in costs. In the current context, it is possible to increase the output and area with energy cost growths of 0.423 and 0.375% points, respectively, and increase the total crops output/ha growth and the utilised agricultural area with energy costs/ha growth of 0.243 and −0.225% points, respectively.

Miscanthus is a high yielding bioenergy crop. In this study we used acid presoaking, wet explosion, and enzymatic hydrolysis to evaluate the combination of the different pre-treatment methods for bioethanol production with Miscanthus. Acid presoaking is primarily carried out in order to remove xylose prior to wet explosion. The acid presoaking extracted 63.2% xylose and 5.2% glucose. Direct enzymatic hydrolysis of the presoaked biomass was found to give only low sugar yields of 24-26% glucose. Wet explosion is a pre-treatment method that combines wet-oxidation and steam explosion. The effect of wet explosion on non-presoaked and presoaked Miscanthus was investigated using both atmospheric air and hydrogen peroxide as the oxidizing agent. All wet explosion pre-treatments showed to have a disrupting effect on the lignocellulosic biomass, making the sugars accessible for enzymatic hydrolysis. The combination of presoaking, wet explosion, and enzymatic hydrolysis was found to give the highest sugar yields. The use of atmospheric air gave the highest xylose yield (94.9% xylose, 61.3% glucose), while hydrogen peroxide gave the highest glucose yield (82.4% xylose, 63.7% glucose).

Abstract The methane productivity of manure in terms of volatile solids (VS), volume and livestock production was determined. The theoretical methane productivity is higher in pig (516 l kg −1 VS ) and sow (530 l kg −1 VS ) manure than in dairy cattle manure (469 l kg −1 VS ) , while the ultimate methane yield in terms of VS is considerably higher in pig (356 l kg −1 VS ) and sow manure (275 l kg −1 VS ) than in dairy cattle manure (148 l kg −1 VS ) . Methane productivity based on livestock units (LU) shows the lowest methane productivity for sows (165 m 3 CH 4 LU −1 ) , while the other animal categories are in the same range (282– 301 m 3 CH 4 LU −1 ). Pre-treatment of manure by separation is a way of making fractions of the manure that have a higher gas potential per volume. Theoretical methane potential and biodegradability of three types of fractions deriving from manure separation were tested. The volumetric methane yield of straw was found to be higher than the yield from total manure and the solid fractions of manure, due to the higher VS content, and hence the use of straw as bedding material will increase the volumetric as well as the livestock-based methane productivity.