DAYCENT model analysis of past and contemporary soil N2O and net greenhouse gas flux for major crops in the USA
DAYCENT model analysis of past and contemporary soil N2O and net greenhouse gas flux for major crops in the USA
复制标题
DOI：
10.1016/j.still.2005.02.007
复制
发表时间：
2005-08-01
影响因子：
6.5
通讯作者：
Ojima, DS
中科院分区：
文献类型：
--
作者：
Del Grosso, SJ;Mosier, AR;Ojima, DS
使用DAYCENT生态系统模型（世纪的每日版本）和政府间气候变化专门委员会使用的排放因子（EF）方法来估计美国主要种植系统的直接和间接N2 O排放量。EF方法目前用于美国温室气体清单，但基于过程的模型，如DAYCENT，可能会产生更可靠的结果，因为它们考虑了EF忽略的土壤类型，气候和耕作强度等因素。用DAYCENT和EF估算的土壤N_2O通量与不同种植制度的实测数据比较，r（2）值分别为0.74和0.67，平均偏差分别为-6%和+13%。在全国范围内，DAYCENT模拟的N2 O排放总量比使用EF估计的低25%。对于这两种模式，N2 O排放量最高的是在美国中部，其次是西北，西南，东南和东北地区。该模型模拟了大致相等的直接N2 O排放施肥作物，但EF估计更大的直接N2 O排放比DAYCENT固氮作物。DAYCENT和EF估计的间接N2 O排放的气体成分（NO + NH3）差别不大，但DAYCENT估计约两倍的间接排放量从NO3淋溶，因为它包括了N的贡献，而EF没有。DAYCENT模拟还进行了免耕种植，1940年前的作物管理，和本地植被。DAYCENT模拟的N2 O、CO2和CH 4通量被转换为CO2-C当量，并与燃料使用估计相结合，以估计净全球变暖潜势（GWP（net））。近期非水稻（Oryza sativa L.）常规耕作下的主要作物为0.43 Mg C ha（-1）yr（-1），免耕下的主要作物为0.29 Mg C ha（-1）yr（-1），工业化前的作物为0.25 Mg C ha（-1）yr（-1），本地系统为-0.15 Mg C ha（-1）yr（-1）。DAYCENT的结果表明，在全国范围内，转换为免耕可以减少美国农业排放的20%或美国温室气体排放总量的1.5%。(c)2005 Elsevier B. V.保留所有权利。
The DAYCENT ecosystem model (a daily version of CENTURY) and an emission factor (EF) methodology used by the Intergovernmental Panel on Climate Change were used to estimate direct and indirect N2O emission for major cropping systems in the USA. The EF methodology is currently used for the USA greenhouse gas inventory but process based models, such as DAYCENT, may yield more reliable results because they account for factors such as soil type, climate, and tillage intensity that are ignored by EF. Comparison of mean annual soil N2O flux estimated by DAYCENT and EF with measured data for different cropping systems yielded r(2) values of 0.74 and 0.67, and mean deviations of -6 and +13%, respectively. At the national scale, DAYCENT simulation of total N2O emission was similar to 25% lower than estimated using EF. For both models, N2O emission was highest in the central USA followed by the northwest, southwest, southeast, and northeast regions. The models simulated roughly equivalent direct N2O emission from fertilized crops, but EF estimated greater direct N2O emission than DAYCENT for N-fixing crops. DAYCENT and EF estimates of the gaseous component of indirect N2O emission (NO + NH3) differed little, but DAYCENT estimated approximately twice the indirect emission from NO3 leaching since it included the contribution of N from N-fixing crops while EF did not. DAYCENT simulations were also performed for no tillage cropping, pre-1940 crop management, and native vegetation. DAYCENT-simulated N2O, CO2, and CH4 fluxes were converted to CO2-C equivalents and combined with fuel use estimates to estimate net global warming potential (GWP(net)). GWP(net) for recent non-rice (Oryza sativa L.) major cropping was 0.43 Mg C ha(-1) yr(-1) under conventional tillage and 0.29 Mg C ha(-1) yr(-1) under no tillage, for pre-industrial cropping was 0.25 Mg C ha(-1) yr(-1), and for native systems was -0.15 Mg C ha(-1) yr(-1). Results from DAYCENT suggest that conversion to no tillage at the national scale could mitigate similar to 20% of USA agricultural emission or similar to 1.5% of total USA emission of greenhouse gases. (c) 2005 Elsevier B.V. All rights reserved.