Journal of Energy Bioscience 2025, Vol.16, No.3, 105-116 http://bioscipublisher.com/index.php/jeb 107 medium-depth tillage. This can improve the soil structure, retain water and nutrients, and keep the temperature suitable. Seedlings are easier to survive the winter and grow faster, which will eventually increase the yield (Wang et al., 2023a). In arid or semi-arid areas, water-saving methods such as ridges and furrows to collect rainwater and mulching are particularly effective. These measures can increase the water storage in the soil, enhance photosynthesis and water use efficiency, and finally increase yields and bring better economic returns (Wang et al., 2023b). The method of irrigation and nitrogen fertilizer application is also critical. Reasonable watering and appropriate nitrogen fertilizer application can make the stems of rapeseed firm, less prone to lodging, and higher yield (Brčić et al., 2023; Guo et al., 2024). In addition, timely weeding and drainage should not be ignored, which can help stabilize and increase yields (Zhang et al., 2020). 3.2 Varietal development: advances in breeding for dual-use (oil + biomass) cultivars In recent years, the direction of breeding has begun to change. People not only want rapeseed that produces more oil, but also want the kind that can provide more biomass. By improving genotypes and utilizing hybrid advantages, some varieties can not only ensure more grains, but also leave a lot of high-quality straw and pods for use as biomass raw materials (Zheng et al., 2022; Brčić et al., 2023). Different rapeseed varieties respond differently to nitrogen fertilizers. Some grow more vigorously when there is more nitrogen fertilizer, with higher biomass and energy value, and better combustion effect (Brčić et al., 2023). The future breeding goal is to design high-yield and versatile varieties, combining ideal design and hybrid advantage (Zheng et al., 2022). 3.3 Yield influencing factors: climate, plant density, harvesting time The biomass yield of rapeseed is affected by many factors, mainly climate, planting density and when to harvest. Generally speaking, it is more appropriate to control the density of 25 to 37 plants per square meter when sowing in October, which helps to stabilize and increase yield (Xie et al., 2023). If the density is too small or too dense, there will be problems. It is ideal to control it between 360 000 and 540 000 plants per hectare. This will allow the plant to better distribute nutrients, the canopy structure will be more reasonable, and help improve the efficiency of light energy utilization (Xie et al., 2023; Lin et al., 2024b). A new approach is to mix tall and short stalks. As long as the proportion of tall stalks does not exceed 20%, space and light are better utilized, and the yield increase is also obvious (Lin et al., 2024a). Local weather conditions, such as precipitation and temperature, will also affect the final yield. The time of harvesting should also be chosen early or late, and it is best to adjust management methods according to local conditions (Zhang et al., 2020; Brčić et al., 2023). 4 Conversion Technologies for Energy Production 4.1 Thermochemical processes 4.1.1 Combustion Byproducts of rapeseed, such as rapeseed cake and pellets, can be burned directly. These biomasses can provide heat and electricity. Studies have found that rapeseed pellets, a byproduct of biodiesel production, can not only feed livestock, but also burn well in boilers. This usage is not only environmentally friendly, but also suitable for daily scenarios such as household water heaters (Ciunel and Klugmann-Radziemska, 2014; Suchocki, 2024). Relevant data show that rapeseed oil and its byproducts are feasible as alternative fuels (Suchocki, 2024). 4.1.2 Pyrolysis Pyrolysis is an important technology for converting biomass such as rapeseed straw and stems into energy. Slow pyrolysis is generally carried out between 350 ℃ and 650 ℃. At 650 ℃ and a faster heating rate, the most pyrolysis oil can be obtained, which can be used as biofuel (Karaosmanoğlu et al., 1999). If rapeseed residue is pyrolyzed, 35%~40% of biochar can be obtained. These charcoals have a high calorific value (greater than 34 kJ/g) and can be used directly as energy (Güleç et al., 2022a; 2022b) (Figure 1). 4.1.3 Gasification Although this abstract does not explain in detail how to gasify rapeseed, other studies have said that gasification is another effective thermochemical method. Rapeseed, a lignocellulosic biomass, can also be converted into energy in this way. Gasification can also be combined with other renewable energy technologies to make it more environmentally friendly (Lee et al., 2023; Tshikovhi and Motaung, 2023).
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