Journal of Energy Bioscience 2025, Vol.16, No.4, 172-181 http://bioscipublisher.com/index.php/jeb 175 The reducing sugar and water content in sweet potatoes affect the production of biogas. Some good varieties are more advantageous in converting biomass into energy (De Paula Batista et al., 2019). 4.3 Cost and input analysis Growing sweet potatoes does not require much labor and fertilizer, which is very suitable for rural areas with more manpower but less funds. If local fertilizers can be used, healthy seedlings can be selected, and some biological and physical methods can be used to prevent insects and diseases, the cost of planting can be further reduced and the income can be increased. Now high-resolution remote sensing technology can also be used to help, which can manage the work in the field more accurately, increase production, and make better use of land (Tedesco et al., 2023). 4.4 Byproduct utilization In addition to being used for fermentation to produce biogas, sweet potatoes also have many by-products that can be used. For example, its starch can be used as food or industrial raw materials, and the residue after fermentation can also be used to feed livestock. In this way, resources are more fully utilized. This multi-use approach not only increases the overall value of the sweet potato industry, but also contributes to the sustainable development of the rural economy (Tedesco et al., 2023). 5 Environmental and Sustainability Assessment Sweet potato is a high-yield root crop with low soil requirements. It has great potential for use as biomass energy in rural China. If it is used to produce biogas, whether it is good for the environment needs to be considered from multiple aspects, such as greenhouse gas emissions, land use, biodiversity, water and fertilizer consumption, and the impact of the entire life cycle. 5.1 Greenhouse gas mitigation potential Using sweet potato fermentation to produce biogas can reduce greenhouse gas emissions. On the one hand, rural energy such as coal, firewood and liquefied gas can be replaced by sweet potato biogas, reducing dependence on carbon energy. On the other hand, biogas residue and biogas liquid can be returned to the fields, which can reduce the use of chemical fertilizers and reduce N2O emissions caused by nitrogen fertilizers. Some studies have estimated that each ton of sweet potato can produce about 60 to 80 cubic meters of biogas. If a farmer uses 1 ton of sweet potato to produce biogas per year, it can reduce about 180 to 250 kilograms of carbon dioxide equivalent. Compared with straw, sweet potatoes are more suitable for small-scale household use and have higher fermentation efficiency (Hou et al., 2017; Sun et al., 2022). 5.2 Land use and biodiversity considerations Sweet potatoes are often planted on sloping land, dry land, or in the gaps between crop rotations. This way, they will not compete with major food crops for land, and both food and energy can be obtained. It can also have a good yield on marginal land, and is suitable for promotion in some mountainous areas in southwest and central China, which is very helpful for the development of rural ecological agriculture. It should also be noted that sweet potatoes should not be planted too intensively. If they are planted too singly, biodiversity may be affected. Therefore, it is recommended to use mixed cropping or crop rotation when planting sweet potatoes, and also consider combining them with local ecological protection plans, so that the agricultural system can be more stable (Zhang and Qiu, 2018; Li et al., 2025). 5.3 Water and nutrient requirements Compared with water-intensive crops such as corn, sweet potatoes require less water. It also has strong adaptability to rainfall and soil, and is a relatively water-saving energy crop. It does not require high fertilizers, mainly phosphorus and potassium, and has less demand for nitrogen, which can also reduce water pollution caused by too much nitrogen fertilizer. Some studies have put forward several suggestions, such as: the water consumption per hectare of sweet potato planting should not exceed 3 500 cubic meters; organic fertilizer substitution should reach at least 40%; nitrogen fertilizer use should be controlled at no more than 80 kilograms
RkJQdWJsaXNoZXIy MjQ4ODYzNA==