Life Cycle Greenhouse Gas Emissions for Irrigated Corn Production in the U.S. Great Plains
Life Cycle Greenhouse Gas Emissions for Irrigated Corn Production in the U.S. Great Plains
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DOI：
10.1016/j.envc.2023.100750
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发表时间：
2023-07
影响因子：
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通讯作者：
R. Koushki;Sumit Sharma;J. Warren;M. Foltz
中科院分区：
文献类型：
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作者：
R. Koushki;Sumit Sharma;J. Warren;M. Foltz
农业管理实践提高了农作物产量，以满足不断增长的人口的粮食需求。然而，这些活动可能会产生负面后果，包括导致全球气候变化的温室气体 (GHG) 排放。为了缓解这一全球环境问题，应确定对系统温室气体排放影响最大的管理实践，并有针对性地减少排放。因此，我们在半干旱的美国大平原的一个实验田中估算了在农民选择的各种情景下，灌溉玉米生产从摇篮到产品的温室气体排放量。我们应用碳足迹方法来量化 2020 年俄克拉荷马州测试农业性能解决方案 (TAPS) 喷水器玉米竞赛中 14 个场景中与田前（例如能源生产、化肥生产）和田内（例如抽取地下水、施肥）活动相关的生命周期温室气体排放。我们确定，玉米生产温室气体排放总量的 63% 与田间活动有关，农业土壤排放是总体驱动因素。预计农业土壤中的土壤生化过程将平均贡献 89 ± 18 g CO2-eq kg−1 玉米，而这些系统估计的总产量为 271 ± 46 g CO2-eq kg−1 玉米。农业地下水抽取的现场天然气燃烧、田前肥料生产和地下水抽取的田前能源生产是对温室气体排放总量影响最大的参数。柴油、种子和除草剂生产对玉米生产的温室气体排放总量的贡献微乎其微。该模型对模拟的农业土壤温室气体排放最为敏感，其排放因子具有显着的不确定性。因此，未来的工作应针对实地测量，以更好地预测直接土壤排放对温室气体排放总量的贡献，特别是在不同的管理下。此外，确定灌溉水和肥料的最佳施用量将有助于减少地下水灌溉作物的温室气体排放。
Agricultural management practices improve crop yields to satisfy food demand of the growing population. However, these activities can have negative consequences, including the release of greenhouse gas (GHG) emissions that contribute to global climate change. To mitigate this global environmental problem, the management practices that contribute the most to system GHG emissions should be identified and targeted to mitigate emissions. Accordingly, we estimated the cradle-to-product GHG emissions of irrigated corn production under various farmer-selected scenarios at an experimental testing field in the semi-arid U.S. Great Plains. We applied a carbon footprint approach to quantify life cycle GHG emissions associated with pre-field (e.g., energy production, fertilizer production) and in-field (e.g., groundwater pumping, fertilizer application) activities within fourteen scenarios in the 2020 Oklahoma Testing Ag Performance Solutions (TAPS) sprinkler corn competition. We determined that 63% of the total GHG emission from corn production was associated with in-field activities and that agricultural soil emissions were the overall driving factor. Soil biochemical processes within agricultural soils were expected to contribute an average of 89 ± 18 g CO2-eq kg−1corn of the total 271 ± 46 g CO2-eq kg−1corn estimated from these systems. On-site natural gas combustion for agricultural groundwater pumping, pre-field fertilizer production, and pre-field energy production for groundwater pumping were the next most influential parameters on total GHG emissions. Diesel fuel, seed, and herbicide production had insignificant contributions to total GHG emissions from corn production. The model was most sensitive to the modeled GHG emissions from agricultural soil, which had significant uncertainty in the emission factor. Therefore, future efforts should target field measurements to better predict the contribution of direct soil emissions to total GHG emissions, particularly under different managements. In addition, identifying the optimal application rate of irrigation water and fertilizer will help to decrease GHG emissions from groundwater irrigated crops.