Journal of Energy Bioscience 2025, Vol.16, No.3, 105-116 http://bioscipublisher.com/index.php/jeb 110 6.2 Soil and water impacts: residue retention vs. complete biomass removal Rapeseed leaves residues after harvest, and how these residues are handled will affect soil and water resources. If they are left in the field, they can not only increase soil organic matter, but also prevent soil erosion and make the soil more water-retaining (Esmaeilpour-Troujeni et al., 2021). However, if all the residues are removed, the soil may become poorer and water will be easily lost. Therefore, it is better to retain some of the residues. At the same time, reducing water and pesticides in the production process and using more organic fertilizers can not only increase yields, but also make the entire system more environmentally friendly and sustainable. 6.3 Economic viability: cost-benefit analysis across energy conversion pathways Whether rapeseed biomass can make money depends on many factors. Studies have shown that the larger the scale of biodiesel production, the lower the cost. However, the cost of growing rapeseed is still the key to determining profitability (Yang et al., 2022). Fortunately, there are by-products in the production process, such as rapeseed meal and pellets, which can be used to feed animals or burn as fuel, making the entire project more cost-effective (Ciunel and Klugmann-Radziemska, 2014; Suchocki, 2024). Whether it is making biodiesel, burning pellets or hybrid power generation, the cost-effectiveness of different methods is different. It should be considered together based on the price of raw materials, the market conditions of the energy market and whether there is policy support (Ciunel and Klugmann-Radziemska, 2014; Jahangir and Cheraghi, 2020). 6.4 Policy frameworks: subsidies, carbon credits, and renewable mandates The role of policies is very critical. Policy tools such as subsidies, carbon credits, and renewable energy quotas can make projects more profitable and encourage more people to use renewable energy (Bacenetti, 2020; Jahangir and Cheraghi, 2020). Different places have different resources and conditions, and policies must be formulated in accordance with local realities. Using regionalized LCA models for analysis can help find a better balance between environmental protection and economy (Bacenetti, 2020; Yang et al., 2022). 7 Integration with Circular Economy and Agricultural Systems 7.1 Byproduct utilization: biochar, digestate for soil amendment Rapeseed biomass has many uses in the circular economy. Through pyrolysis technology, agricultural waste such as rapeseed meal can be converted into biochar, gas and bio-oil. The yield of biochar can reach 53%, and it has good stability and strong surface activity. It can improve soil quality and lock carbon when used in the soil (Yrjälä et al., 2022; Gallorini et al., 2023). Rapeseed and byproducts can also produce biogas and digestate through anaerobic fermentation. This digestate can be used as organic fertilizer and returned to the fields, which not only improves soil fertility, but also allows nutrients to circulate and reduces dependence on chemical fertilizers (Haque et al., 2023; Rodríguez-Espinosa et al., 2023; van Selm et al., 2025) (Figure 3). These byproducts are well utilized, which not only reduces the accumulation of agricultural waste, but also promotes the sustainable development of agriculture. 7.2 Crop rotation and residue management: enhancing soil fertility In circular agriculture, the rotation of rapeseed and other crops, coupled with the proper treatment of straw, is very helpful for soil health. Rapeseed straw is an organic residue that can be used through composting, returning to the field or making biochar. These methods can increase the organic matter in the soil, improve the soil structure, and promote the growth of microorganisms, thereby improving soil fertility and crop yields (Duque-Acevedo et al., 2020; Rodias et al., 2020; Rodríguez-Espinosa et al., 2023; Toplicean and Datcu, 2024). These organic wastes will release nitrogen after decomposition, which can be absorbed by crops, reducing dependence on chemical fertilizers and reducing greenhouse gas emissions (Rodias et al., 2020; Rodríguez-Espinosa et al., 2023). Crop rotation plus straw management can make agriculture more efficient and environmentally friendly, and is a key practice in building a green agricultural system. 7.3 Biorefinery concept: maximizing value from rapeseed through multi-product recovery The core idea of biorefining is to “eat up” rapeseed biomass as much as possible. For example, rapeseed can be pressed for oil as fuel, and the remaining meal and husk should not be wasted. They can be used to extract protein,
RkJQdWJsaXNoZXIy MjQ4ODYzNA==