Sources of energy fossil consumption as a percentage of the total and in mega joules of five background-finishing systems of eastern Uruguay

Table 11. 
Sources of energy fossil consumption as a percentage of the total and in mega joules of five background-finishing systems of eastern Uruguay. (Note: RL: rangeland systems; SP: seeded pasture systems; FL: feedlot systems.)
Abstract Carbon footprint is a key indicator of the contribution of food production to climate change and its importance is increasing worldwide. Although it has been used as a sustainability index for assessing production systems, it does not take into account many other biophysical environmental dimensions more relevant at the local scale, such as soil erosion, nutrient imbalance, and pesticide contamination. We estimated carbon footprint, fossil fuel energy use, soil erosion, nutrient imbalance, and risk of pesticide contamination for five real beef background-finishing systems with increasing levels of intensification in Uruguay, which were combinations of grazing rangelands (RL), seeded pastures (SP), and confined in feedlot (FL). Carbon footprint decreased from 16.7 (RL–RL) to 6.9 kg (SP–FL) CO2 eq kg body weight−1 (BW; 'eq': equivalent). Energy use was zero for RL–RL and increased up to 17.3 MJ kg BW−1 for SP–FL. Soil erosion values varied from 7.7 (RL–RL) to 14.8 kg of soil kg BW−1 (SP–FL). Nitrogen and phosphorus nutrient balances showed surpluses for systems with seeded pastures and feedlots while RL–RL was deficient. Pesticide contamination risk was zero for RL–RL, and increased up to 21.2 for SP–FL. For the range of systems studied with increasing use of inputs, trade-offs were observed between global and local environmental problems. These results demonstrate that several indicators are needed to evaluate the sustainability of livestock production systems.

表 11. 乌拉圭东部五种背景育肥系统的能源消耗来源，占总能源消耗的百分比及以兆焦耳计的化石能源消耗。（注：RL：牧场系统；SP：播种草地系统；FL：饲养场系统。）摘要碳足迹是衡量食品生产对气候变化贡献的关键指标，其在全球范围内的重要性日益凸显。尽管碳足迹已被用作评估生产系统的可持续性指标，但它并未考虑更多与地方尺度更为相关的生物物理环境维度，例如土壤侵蚀、营养失衡和农药污染。我们对乌拉圭五种实际的牛肉背景育肥系统进行了碳足迹、化石燃料能源消耗、土壤侵蚀、营养失衡和农药污染风险的估算，这些系统结合了牧场（RL）、播种草地（SP）和饲养场（FL）的育肥方式，且其集约化程度逐渐提高。碳足迹从 16.7 kg（RL-RL）降至 6.9 kg CO2 eq kg body weight−1（BW；'eq'：当量）。能源消耗在 RL-RL 中为零，而在 SP-FL 中增至 17.3 MJ kg BW−1。土壤侵蚀值从 7.7 kg（RL-RL）至 14.8 kg 土壤 kg BW−1（SP-FL）不等。氮和磷营养平衡显示，播种草地和饲养场系统的营养过剩，而 RL-RL 则存在营养不足。RL-RL 的农药污染风险为零，而在 SP-FL 中增至 21.2。在研究了输入使用量逐渐增加的系统范围内，观察到全球和地方环境问题之间的权衡。这些结果证明，评估畜牧业生产系统的可持续性需要多个指标。