Potential mitigation of midwest grass-finished beef production emissions with soil carbon sequestration in the United States of America
Potential mitigation of midwest grass-finished beef production emissions with soil carbon sequestration in the United States of America
复制标题
DOI：
--
复制
发表时间：
2016-12
期刊：
影响因子：
--
通讯作者：
J. Rowntree;R. Ryals;M. DeLonge;W. Teague;M. Chiavegato;Peter Byck;Tong Wang;Sutie Xu
中科院分区：
文献类型：
--
作者：
J. Rowntree;R. Ryals;M. DeLonge;W. Teague;M. Chiavegato;Peter Byck;Tong Wang;Sutie Xu
牛肉生产可能对环境有害，这在很大程度上是因为与之相关的肠道甲烷(CH4)的产生，这导致了气候变化。然而，管理良好的放牧系统中的牛肉生产可以帮助土壤碳固存(SCS)，而在评估牛肉生产对气候变化的影响时，这一点往往被忽视。为了评估中西部上部草制牛肉生产系统的碳足迹和减缓气候变化的潜力，我们进行了部分生命周期评估(LCA)，比较了两种放牧管理策略：1)不灌溉、少放牧(1.0AU/ha)、高密度(100,000 kg LW/ha)系统(MOB)和2)灌溉、大量储存(2.5 AU/ha)、低密度(30,000 kg LW/ha)系统(IRG)。在每个系统中，4月出生的母牛在11月断奶，冬季基础饲喂6个月，放牧到次年11月结束，平均屠宰时间为19个月，热屠体重295公斤。作为生命周期评估的基础，我们使用了密歇根州莱克城湖城研究中心两年的数据。我们包括与肠道CH4有关的温室气体(GHG)排放、土壤N2O和CH4通量、紫花苜蓿和矿物补充剂以及农场能源使用。我们还使用政府间气候变化专门委员会(IPCC)的肠道排放方程生成了LCA的结果。我们评估了一系列土壤碳(C)的潜在损失率或增益率，最高可达3mgC ha-1年。肠道CH4对总排放量的影响最大，但这一影响因放牧制度而异。在陆地上，肠道CH4分别占IRG和MOB排放量的62%和66%。在不考虑SCS的情况下，MOB和IRG都是净温室气体来源。我们的局部生命周期分析表明，当包括SCS势时，每种放牧策略都可能是一个整体汇。敏感性分析表明，MOB和IRG系统中的土壤需要分别封存1和2 mg C ha-1yr-1才能实现净零温室气体足迹。IPCC对肠道CH4的模型估计与MOB系统的现场估计相似，但对IRG系统的估计更高，这表明在这种情况下，需要更大的SCS 0.62 mg C ha-1年来抵消动物排放。关键词：牧草育肥牛肉，温室气体排放量，土壤有机碳汇数据首次收到：2016年3月30日|最后一次修订收到：2016年11月28日接受：2016年12月5日|在线发表：2016年12月23日骨灰盒：nbn：de：hebis：34-2016111451469
Beef production can be environmentally detrimental due in large part to associated enteric methane (CH4) production, which contributes to climate change. However, beef production in well-managed grazing systems can aid in soil carbon sequestration (SCS), which is often ignored when assessing beef production impacts on climate change. To estimate the carbon footprint and climate change mitigation potential of upper Midwest grass-finished beef production systems, we conducted a partial life cycle assessment (LCA) comparing two grazing management strategies: 1) a non-irrigated, lightly-stocked (1.0 AU/ha), high-density (100,000 kg LW/ha) system (MOB) and 2) an irrigated, heavily-stocked (2.5 AU/ha), low-density (30,000 kg LW/ha) system (IRG). In each system, April-born steers were weaned in November, winter-backgrounded for 6 months and grazed until their endpoint the following November, with average slaughter age of 19 months and a 295 kg hot carcass weight. As the basis for the LCA, we used two years of data from Lake City Research Center, Lake City, MI. We included greenhouse gas (GHG) emissions associated with enteric CH4, soil N2O and CH4 fluxes, alfalfa and mineral supplementation, and farm energy use. We also generated results from the LCA using the enteric emissions equations of the Intergovernmental Panel on Climate Change (IPCC). We evaluated a range of potential rates of soil carbon (C) loss or gain of up to 3 Mg C ha-1 yr-1. Enteric CH4 had the largest impact on total emissions, but this varied by grazing system. Enteric CH4 composed 62 and 66% of emissions for IRG and MOB, respectively, on a land basis. Both MOB and IRG were net GHG sources when SCS was not considered. Our partial LCA indicated that when SCS potential was included, each grazing strategy could be an overall sink. Sensitivity analyses indicated that soil in the MOB and IRG systems would need to sequester 1 and 2 Mg C ha-1 yr-1 for a net zero GHG footprint, respectively. IPCC model estimates for enteric CH4 were similar to field estimates for the MOB system, but were higher for the IRG system, suggesting that 0.62 Mg C ha-1 yr-1 greater SCS would be needed to offset the animal emissions in this case. Key words: Grass-finishing beef, GHG emissions, Soil organic carbon sequestration Data of the article First received : 30 March 2016 | Last revision received : 28 November 2016 Accepted : 05 December 2016 | Published online : 23 December 2016 URN: nbn:de:hebis:34-2016111451469