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农田土壤固碳潜力研究的关键科学问题 总被引：26，自引：1，他引：25
农田生态系统在陆地生态系统碳循环中扮演着重要的角色。增加农田土壤有机碳的固定不仅可减少大气CO2含量,而且对保障国家粮食安全具有举足轻重的作用。近年来评估土壤固碳潜力已成为国际科学界研究的热点和难点。但由于不同研究者对“潜力”范畴的界定不同,全球或区域尺度农田土壤固碳潜力的估算还存在很大的不确定性。所谓固碳潜力,即土壤碳的饱和水平或土壤所容纳碳的最大能力。这一能力受区域气候、土壤类型、农业管理措施的综合影响。故此,合理地评价固碳潜力,应综合考虑气候、土壤和农业措施诸因素,并将宏观尺度与微观尺度的研究结合起来。从固碳潜力概念范畴及研究方法出发,阐述了农田土壤固碳潜力的研究现状,并结合生物潜力和物理化学潜力的研究,提出区域农田土壤固碳潜力的计量方案,并就该研究领域亟需回答的科学问题进行了探讨。 相似文献
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Net primary production(NPP)of crop represents the capacity of sequestrating atmospheric CO_2 in agro-ecosystem,and it plays an important role in terrestrial carbon cycling.By linking the Crop-C model with climate change scenario projected by a coupled GCM FGOALS via geographical information system (GIS)techniques,crop NPP in China was simulated from 2000 to 2050.The national averaged surface air temperature from FGOALS is projected to increase by 1.0℃over this period and the corresponding atmospheric CO_2 concentration is 535 ppm by 2050 under the IPCC AIB scenario.With a spatial resolution of 10×10 km~2,model simulation indicated that an annual average increase of 0.6 Tg C yr~(-1)(Tg=10~(12)g) would be possible under the AIB scenario.The NPP in the late 2040s would increase by 5%(30 Tg C) within the 98×10~6 hm~2 cropland area in contrast with that in the early 2000s.A further investigation suggested that changes in the NPP would not be evenly distributed in China.A higher increase would occur in a majority of regions located in eastern and northwestern China,while a slight reduction would appear in Hebei and Tianjin in northern China.The spatial characteristics of the crop NPP change are attributed primarily to the uneven distribution of temperature change. 相似文献
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Net primary production （NPP） of crop represents the capacity of sequestrating atmospheric CO2 in agro-ecosystem, and it plays an important role in terrestrial carbon cycling. By linking the Crop-C model with climate change scenario projected by a coupled GCM FGOALS via geographical information system （GIS） techniques, crop NPP in China was simulated from 2000 to 2050. The national averaged surface air temperature from FGOALS is projected to increase by 1.0℃ over this period and the corresponding atmospheric CO2 concentration is 535 ppm by 2050 under the IPCC A1B scenario. With a spatial resolution of 10 ×10 km^2, model simulation indicated that an annual average increase of 0.6 Tg C yr^-1 （Tg=10^12 g） would be possible under the A1B scenario. The NPP in the late 2040s would increase by 5% （30 Tg C） within the 98×10^6 hm^2 cropland area in contrast with that in the early 2000s. A further investigation suggested that changes in the NPP would not be evenly distributed in China. A higher increase would occur in a majority of regions located in eastern and northwestern China, while a slight reduction would appear in Hebei and Tianjin in northern China. The spatial characteristics of the crop NPP change are attributed primarily to the uneven distribution of temperature change. 相似文献
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To quantitatively address the role of tissue N in crop respiration under various agricultural practices, and to consequently evaluate the impact of synthetic fertilizer N application on biomass production and respiration, and hence net carbon fixation efficiency （Encf）, pot and field experiments were carried out for an annual rotation of a rice-wheat cropping system from 2001 to 2003. The treatments of the pot experiments included fertilizer N application, sowing date and planting density. Different rates of N application were tested in the field experiments. Static opaque chambers were used for sampling the gas. The respiration as CO2 emission was detected by a gas chromatograph. A successive biomass clipping method was employed to determine the crop autotrophic respiration coefficient （Ra）. Results from the pot experiments revealed a linear relationship between Ra and tissue N content as Ra = 4.74N-1.45 （R^2= 0.85, P 〈 0.001）. Measurements and calculations from the field experiments indicated that fertilizer N application promoted not only biomass production but also increased the respiration of crops. A further investigation showed that the increase of carbon loss in terms of respiration owing to fertilizer N application exceeded that of net carbon gain in terms of aboveground biomass when fertilizer N was applied over a certain rate. Consequently, the Encf declined as the N application rate increased. 相似文献
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华东地区农田土壤有机碳时空格局动态模拟研究 总被引：9，自引：0，他引：9
基于已建成的农田土壤有机碳模型与GIS空间数据库的耦合,对华东6省(市)1980—2000年农田土壤有机碳时空变化进行模拟。结果表明:20年来该区土壤有机碳总体呈增加趋势,其中增加、持平和减少的面积分别占89.3%9、.5%和1.2%。1980—1985年土壤有机碳增加迅速,1985—1991年增加速率最快,其后趋缓。20年来农田土壤有机碳储量累计增加166 Tg,范围为140~193 Tg。其中安徽和江苏SOC储量增加量约占总增量的59.3%,上海、福建、江西和浙江占40.7%。 相似文献
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旱作农田是N2O的主要排放源,削减其N2O排放有助于整体降低农田温室气体排放。运用整合分析(Meta-analysis)的方法,研究了不同农业管理措施对中国小麦和玉米农田N2O排放的影响,并估算了各减排措施的减排潜力。结果表明：添加抑制剂可显著减少小麦和玉米农田N2O排放36%~46%,并增加作物产量;施氮量减少30%以内,可削减N2O排放10%~18%,且对产量无明显影响;施用缓(控)释肥和秸秆还田能显著减少小麦田N2O排放,但对玉米田的减排效果并不显著。在不同的减排措施下,中国小麦和玉米农田N2O减排潜力分别为9.29~13.90 Gg N2O-N/生长季和10.53~23.19 Gg N2O-N/生长季。河南、山东、河北和安徽省小麦田减排潜力最大,占全国小麦田N2O减排潜力的53%;黑龙江、吉林、山东、河北和河南省玉米田减排潜力最大,约占全国玉米田N2O减排潜力的50%。 相似文献
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1990～2000年中国稻田甲烷排放变化模拟 总被引：3，自引：0，他引：3
甲烷（CH4）是大气中重要的温室气体之一。研究我国稻田的甲烷排放年际变化,客观评估我国稻田CH4排放量,对于区域乃至全球大气CH4浓度的贡献具有积极意义。本文将一个比较成熟的稻田甲烷排放模型CH4MOD和G IS空间化数据库结合,模拟估计了中国大陆1990～2000年水稻生长季稻田甲烷排放的年际变化。模拟结果表明:从1990年到2000年,我国稻田甲烷排放量具有比较明显的年际波动,其中1993～1995年由于播种面积较少,甲烷排放为一个低谷,排放量约为5.37Tg;其他年份的排放量在5.93～6.22Tg之间。虽然1997年之后我国水稻播种面积比1993年之前少约1.84×106hm2,但两个时期的甲烷排放量却基本相等,这主要是由于1997年之后单位面积稻田甲烷的排放也较1993年之前高的缘故。从空间格局方面讲,我国稻田甲烷排放的高值区主要分布在湖南、湖北、江西、广东、广西、四川、江苏和安徽,东北地区稻田甲烷排放在20世纪90年代有逐年增加的趋势。 相似文献
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