In the context of ever-growing demand for food and associated concerns regarding the environmental impacts of high-input agricultural systems, there is growing interest in mixed farm enterprises to deliver greater sustainability compared with mono-enterprise production systems. However, assessments of such systems are complex and require high-resolution data to determine the true value and interconnectivity across enterprises. Given the scarcity of information on mixed crop–livestock systems and the difficulties of its analysis, we perform life cycle assessment using temporally high-resolution data (2019–2022) from a long-term experiment in South America to evaluate the ‘cradle-to-farmgate exit’ greenhouse gas emissions intensities of four rotational crop–livestock systems. Systems evaluated were continuous cropping: 2 years of continuous cropping; short rotation: 2-year continuous cropping plus 2-year pasture; long rotation: 2-year continuous cropping followed by 4-year pasture; and forage rotation: continuous pasture. Emissions intensities for beef throughput were reported as kilograms of carbon dioxide equivalents (CO₂-eq) per kilogram of liveweight gain (LWG) using the Intergovernmental Panel for Climate Change’s Sixth Assessment Report (AR6 2021) CO₂ characterisation factors. Point estimate results were found to be 11.3, 11.8, 11.8 and 16.4 kg CO₂-eq/kg/LWG for continuous cropping, short rotation, long rotation and forage rotation, respectively. Emission averages arising from crops, which were separated from animal-based emissions using economic allocation, were 1.23, 0.53 and 0.52 kg CO₂-eq/kg for soybean, wheat and oat, respectively. The inclusion of soil organic carbon stock changes had notable effects on reducing each system’s emissions: by 22.4%, 19.2%, 25.3% and 42.1% under continuous cropping, short rotation, long rotation and forage rotation, respectively, when soil organic carbon was included. Given there are few life cycle assessment studies available on such mixed-enterprise ‘semi-circular’ systems, particularly with novel primary data, this study adds critical knowledge to agri-food-related sustainability literature by addressing environmental issues in complex production systems compared to extant and broad coverage of mono-enterprise systems.

在对粮食的需求不断增长以及对高投入农业系统对环境影响的相关担忧的背景下，人们对混合农业企业越来越感兴趣，因为与单一企业生产系统相比，混合农业企业可以提供更大的可持续性。然而，此类系统的评估很复杂，需要高分辨率数据来确定企业之间的真实价值和互连性。鉴于混合作物-牲畜系统的信息匮乏及其分析的困难，我们使用来自南美洲长期实验的时间高分辨率数据（2019-2022）进行生命周期评估，以评估“从摇篮到”的生命周期评估。 -四种轮作作物-畜牧系统的“农场退出”温室气体排放强度。评估的系统为连作：2年连作；短轮作：2年连作加2年牧草；长轮作：2年连作，4年放牧；牧草轮作：连续放牧。使用政府间气候变化专门委员会第六次评估报告 (AR6 2021)，将牛肉产量的排放强度报告为每公斤活重增加 (LWG) 的二氧化碳当量 (CO ₂ -eq) CO ₂ 特征因素。连作、短轮作、长轮作和牧草轮作的点估计结果分别为 11.3、11.8、11.8 和 16.4 kg CO ₂ -eq/kg/LWG。通过经济分配将作物产生的排放量与动物源排放量分开，大豆、小麦和燕麦的平均排放量分别为 1.23、0.53 和 0.52 kg CO ₂ -eq/kg。 纳入土壤有机碳储量变化对减少各个系统的排放具有显着效果：当纳入土壤有机碳时，连作、短轮作、长轮作和牧草轮作分别减少了 22.4%、19.2%、25.3% 和 42.1% 。鉴于对这种混合企业“半循环”系统的生命周期评估研究很少，特别是对于新颖的原始数据，本研究通过解决复杂生产系统中的环境问题，为农业食品相关的可持续性文献添加了关键知识。单一企业系统现有且广泛的覆盖范围。