土壤学报2017，Vol.54Issue(3)：624-637,14.DOI:10.11766/trxb201607270373
制图尺度对CO2浓度升高情景下旱地土壤有机碳模拟的影响
Effects of Mapping Scale on Simulation of Soil Organic Carbon in Upland in the Scenario of Elevated CO2
摘要
Abstract
[Objective]Agro-ecosystem models have been extensively used to predict changes in soil organic carbon(SOC)in farmland in the scenario of elevated CO2 in future. However,currently most of the studies rely on maps of only one or certain one scale,and little has been done on influence of map scales on prediction of SOC dynamics in the scenario of elevated CO2. China has a total of 140 million hm2 of farmlands,consisting of 110 M hm2 of uplands and 30 M hm2 of paddy fields. As upland soil is enormous in area and high in carbon storage,it plays an important role in sequestrating carbon and mitigating climate change. Owing to the complexity of carbon turnover processes and dynamic response of carbon to environmental conditions,recent years have seen progresses in using process-based models to simulate historic patterns and future trends of SOC variation in agricultural systems. The DeNitrification-DeComposition(DNDC) model based on human activity data,land use,soil parameters,daily temperatures,and precipitation is used to describe biogeochemical processes of C and N recycling in the terrestrial ecosystem. Currently it has been extensively used to explain mechanisms of carbon turnover as affected by the complex interactions among soil management,crops,and climate. [Method] Based on the uplands in North Jiangsu,China, the 1980—2009 meteorological data and 2009 farmland management data of the region,soil databases of six different mapping scales,i.e.,1:50000,1:250000,1:500000,1:1000000,1:4000000,and 1:10000000,and 3 different scenarios set for the period of 2010-2039 with atmospheric CO2 elevation rate being 1.5,2.0 and 3.0 times,respectively,the normal rate(1.9 ppm a-1),this study used the DNDC model to predict carbon sequestration rate and potential as affected by CO2 elevation rate in the region with the data of the most detailed 1:50000 map and quantify the uncertainties of using the soil databases different in mapping scale to simulate SOC dynamics in the upland-crop ecosystem.[Result]Results show that based on the 1:50000 map and in the scenario of the atmospheric CO2 concentration rising at a rate 1.5, 2.0,and 3.0 times the normal rate,the average annual SOC sequestration rate in the topsoil(0~50 cm) layer of the upland of North Jiangsu during the period of 2011—2039 was predicted to be 357,360,and 365 kg hm-2 a-1,respectively,and the total SOC sequestration was 42.08、42.38 and 42.93 Tg C, respectively. However,the prediction varied sharply with scale of the map used. When the average annual C sequestration rate predicted based on the 1:50000 map was used as baseline,the use of the other maps would generated deviations ranging from 0.89% to 58.09%,0.81% to 60.13% and 0.88% to 58.92%,in terms of average annual C sequestration rate and from 0.60 to 59.22%,0.37 to 59.39% and 0.02 to 59.71%in terms of total C sequestration,respectively,in the three scenarios.[Conclusion] It could be concluded that the effect of scale of the map used on prediction of SOC in the scenarios of elevated CO2 is significant. In general,heterogeneity of soil properties in a region would often lead to variation of the prediction of SOC, which is mainly attributed to the disappearance of some soil types and spatial distortion when the map of small scales is polygonized. It is,therefore,essential for studies in future to use soil maps of large scales for data in quantifying regional SOC dynamics.关键词
土壤有机碳/苏北旱地/制图尺度/DNDC模型Key words
Soil organic carbon/Upland of North Jiangsu/Mapping scale/DNDC(Denitrification and Decomposition)model分类
农业科技引用本文复制引用
黄琳斌,张黎明,龙军,于东升,史学正,陈翰阅,范协裕,邢世和..制图尺度对CO2浓度升高情景下旱地土壤有机碳模拟的影响[J].土壤学报,2017,54(3):624-637,14.基金项目
福建省2011计划(K80ND8002)、福建省自然科学基金项目(2015J01154)和福建省高校杰出青年科研人才计划基金(JA13093) 共同资助 Supported by the Collaborative Innovation for Juncao Ecology Industry(No. K80ND8002),the National Science Foundation of Fujian Province,China(No.2015J01154),and the Distinguished Young Scholars Foundation of the Higher Education Institutions of Fujian Province,China(No.JA13093) （K80ND8002）
