气候变化领域集成服务门户(CCPortal): Carbon debt of field-scale conservation reserve program grasslands converted to annual and perennial bioenergy crops

CCPortal

DOI	10.1088/1748-9326/aafc10
	Carbon debt of field-scale conservation reserve program grasslands converted to annual and perennial bioenergy crops
	Abraha M.; Gelfand I.; Hamilton S.K.; Chen J.; Robertson G.P.
发表日期	2019
ISSN	17489318
卷号	14 期号:2
英文摘要	Over 5 million ha of US Conservation Reserve Program (CRP) grasslands have been converted to annual crops since 2000, driven mainly by demand for corn grain ethanol. Much of the soil carbon sequestered under CRP is lost upon conversion, creating a 'carbon debt' that is presumed to be repaid by future greenhouse gas (GHG) savings from ethanol's substitution for petroleum. Model simulations, extrapolations, and national statistics rather than direct measurements have been used thus far to estimate the long-term global warming impact (GWI) of such conversions. Here we report measured GWIs for three 22-year-old CRP grassland fields and three conventionally tilled agricultural (AGR) fields (11-17 ha) converted to either annual no-till corn or perennial cellulosic (switchgrass or restored prairie) bioenergy crops. We assessed GWIs for each field over eight years using whole-system life cycle analysis (LCA) by measuring: (a) GHG fluxes via eddy covariance and static chamber methodologies, (b) farming operations and agronomic inputs, and (c) the fossil fuel offset by ethanol use. Payback times were much longer than those estimated by prior modeling efforts. After 8 years, cumulative GWIs of switchgrass, restored prairie, and corn at the CRP grasslands were, respectively, -2.6 ±4.0, 6.9 ±3.6 and 85.2 ±5.1 Mg CO 2 -equivalent ha -1 . The switchgrass system had repaid its carbon debt by year eight and the restored prairie will have likely repaid by year ten; however, the no-till corn system appears likely to require >300 years. The same bioenergy crops grown on former agricultural lands, with no sequestered carbon lost on conversion, repaid their carbon debts within two years. Results indicate that GWI estimates and carbon debt payback times due to conversion of CRP lands to annual bioenergy crops have been substantially underestimated by current models. © 2019 The Author(s). Published by IOP Publishing Ltd.
英文关键词	corn; fossil fuel; global warming impact (GWI); greenhouse gas (GHG); lifecycle analysis (LCA); restored prairie; switchgrass
语种	英语
scopus关键词	Biofuels; Carbon; Ethanol; Fossil fuels; Gas fuel analysis; Global warming; Greenhouse gases; Life cycle; Plants (botany); Restoration; corn; Global warming impacts (GWI); Greenhouse gas (GHG); Life cycle analysis; restored prairie; Switchgrass; Crops; agricultural land; agronomy; annual plant; bioenergy; debt; energy crop; fossil fuel; global warming; grass; grassland; greenhouse gas; life cycle analysis; maize; perennial plant; soil carbon; United States; Panicum virgatum; Zea mays
来源期刊	Environmental Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/154689
作者单位	Center for Global Change and Earth Observations, Michigan State University, East Lansing, MI 48823, United States; Great Lakes Bioenergy Research Center, Michigan State UniversityMI 48824, United States; W K Kellogg Biological Station, Michigan State University, Hickory Corners, MI 49060, United States; Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, United States; Department of Geography, Environment and Spatial Sciences, Michigan State University, East Lansing, MI 48824, United States; Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
推荐引用方式 GB/T 7714	Abraha M.,Gelfand I.,Hamilton S.K.,et al. Carbon debt of field-scale conservation reserve program grasslands converted to annual and perennial bioenergy crops[J],2019,14(2).
APA	Abraha M.,Gelfand I.,Hamilton S.K.,Chen J.,&Robertson G.P..(2019).Carbon debt of field-scale conservation reserve program grasslands converted to annual and perennial bioenergy crops.Environmental Research Letters,14(2).
MLA	Abraha M.,et al."Carbon debt of field-scale conservation reserve program grasslands converted to annual and perennial bioenergy crops".Environmental Research Letters 14.2(2019).