With the central aim to reduce greenhouse gas emissions, agroforestry systems have become popular because they can provide biomass for bioenergy conversion and thus help replace fossil energy. This article compares the net energy balances of three biomass conversion techniques for an agroforestry system consisting of willows and two types of grassland biomass as well as separate stands of grassland and willow. The period of investigation was the second willow rotation (4–6 years after establishment). The biomass conversion techniques included combustion of hay (CH), integrated generation of solid fuel and biogas from biomass (IFBB), and anaerobic whole crop digestion (WCD). Compared to the first rotation (years 1–3), the net energy yield of the willow stands significantly increased. Nevertheless, the separate stand of willow had higher net energy yield than the agroforestry system. The IFBB technique led to an improvement in solid fuel quality through demineralization. CH and IFBB provided higher net energy yields than WCD.

中文翻译：

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草地和柳树结合的胡同种植系统的净能量平衡和燃料质量：第二轮的结果

以减少温室气体排放为核心目标，农林业系统变得流行，因为它们可以为生物能源转换提供生物质，从而有助于替代化石能源。本文比较了由柳树和两种草地生物量以及草地和柳树独立林分组成的农林复合系统的三种生物质转化技术的净能量平衡。调查期为第二次柳树轮作（定植后4-6年）。生物质转化技术包括干草燃烧 (CH)、生物质固体燃料和沼气综合发电 (IFBB) 和厌氧全作物消化 (WCD)。与第一次轮作（1-3 年）相比，柳林的净能量产量显着增加。尽管如此，单独的柳树林比农林复合系统具有更高的净能量产量。IFBB 技术通过脱矿质提高了固体燃料的质量。CH 和 IFBB 提供比 WCD 更高的净能量产量。