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11.
Soil processes and global change 总被引:43,自引:0,他引:43
A. R. Mosier 《Biology and Fertility of Soils》1998,27(3):221-229
Contributors to the Intergovernmental Panel on Climate Change (IPCC) generally agree that increases in the atmospheric concentration
of greenhouse trace gases (i.e., CO2, CH4, N2O, O3) since preindustrial times, about the year 1750, have led to changes in the earth's climate. During the past 250 years the
atmospheric concentrations of CO2, CH4, and N2O have increased by 30, 145, and 15%, respectively. A doubling of preindustrial CO2 concentrations by the end of the twenty-first century is expected to raise global mean surface temperature by about 2 °C
and increase the frequency of severe weather events. These increases are attributed mainly to fossil fuel use, land-use change,
and agriculture. Soils and climate changes are related by bidirectional interactions. Soil processes directly affect climatic
changes through the production and consumption of CO2, CH4, and N2O and, indirectly, through the production and consumption of NH3, NOx, and CO. Although CO2 is primarily produced through fossil fuel combustion, land-use changes, conversion of forest and grasslands to agriculture,
have contributed significantly to atmospheric increase of CO2. Changes in land use and management can also result in the net uptake, sequestration, of atmospheric CO2. CH4 and N2O are produced (30% and 70%, respectively) in the soil, and soil processes will likely regulate future changes in the atmospheric
concentration of these gases. The soil-atmosphere exchange of CO2, CH4, and N2O are interrelated, and changes in one cycle can impart changes in the N cycle and resulting soil-atmosphere exchange of N2O. Conversely, N addition increases C sequestration. On the other hand, soil processes are influenced by climatic change through
imposed changes in soil temperature, soil water, and nutrient competition. Increasing concentrations of atmospheric CO2 alters plant response to environmental parameters and frequently results in increased efficiency in use of N and water. In
annual crops increased CO2 generally leads to increased crop productivity. In natural systems, the long-term impact of increased CO2 on ecosystem sustainability is not known. These changes may also result in altered CO2, CH4, and N2O exchange with the soil. Because of large temporal and spatial variability in the soil-atmosphere exchange of trace gases,
the measurement of the absolute amount and prediction of the changes of these fluxes, as they are impacted by global change
on regional and global scales, is still difficult. In recent years, however, much progress has been made in decreasing the
uncertainty of field scale flux measurements, and efforts are being directed to large scale field and modeling programs. This
paper briefly relates soil process and issues akin to the soil-atmosphere exchange of CO2, CH4, and N2O. The impact of climate change, particularly increasing atmospheric CO2 concentrations, on soil processes is also briefly discussed.
Received: 1 December 1997 相似文献
12.
基于IPCC的河北省2005年森林碳储量 总被引:1,自引:0,他引:1
基于IPCC的方法,对河北省2005年森林及其它木质生物质碳储量进行了研究.结果表明,河北省2005年森林和其它木质生物质总碳储量为6 111.96万t,折合固定CO2的量为22 410.52万t.现有林以幼、中龄林为主,林分平均碳密度较低,仅为10.32 t·hm-2;按优势树种(树种组)排序,最大的5个碳库为桦树、... 相似文献
13.
XiuFang ZHU 《干旱区科学》2015,7(2):224-237
Projecting future water demand, especially in terms of agricultural irrigation demand, as well as identifying high-risk areas and establishing appropriate water demand management has become increasingly important in China. Climate scenarios provide opportunities to predict future irrigation requirements (IRs). We examined changes in IRs and agricultural drought in response to rising greenhouse gas concentrations in China using eight global climate models from the Intergovernmental Panel on Climate Change Fourth Assessment Report. In this research, Northeast China, the North China Plain and the Yarlung Tsangpo River Valley area in southeastern Tibet were estimated to receive more precipitation in the future, whereas Southeast and Northwest China, especially the Junggar and Tarim basins in Xinjiang Uygur autonomous region, will receive less precipitation. IRs will undergo a significant increase in summer (June–August), especially in July, whereas the smallest increase was predicted to occur in autumn (September–November). Middle rice was identified as the greatest contributor to the increase in total IRs. The areas predicted to experience significant increases in IRs include Northwest China (the Tarim and Junggar basins in Xinjiang Uygur autonomous region, the Hexi Corridor in Gansu province and the Guanzhong Plain in Shaanxi province), Southeast China (especially Fujian province), and Southwest China (Yarlung Tsangpo River Valley area in Tibet and the Sichuan Basin). 相似文献
14.
15.
Global development and the future of the protected area strategy 总被引:1,自引:0,他引:1
Land protection has become increasingly common, and global land protection is now greater than 12%. Prediction of future protected area expansion are uncertain, and depend on understanding the factors that have to date explained the historical pattern and geographic variation in protected area (PA) establishment. We test four major perspectives on factors limiting or facilitating PA creation, differentiating between strict PAs and multiple-use PAs where some resource extraction is permitted. Richer countries had a greater amount of land protection and were more likely to create strict PAs, supporting the view of land protection as an economic amenity, although the magnitude of this effect declines in recent decades. There are also significant differences in amount of protection by political structure, with independent countries tending to protect more land, and education, with countries with high levels of primary education tending to protect more. However, countries with substantial previous protection tend to do less protection and create proportionally fewer strict and more multiple-use PAs. Scenarios of future socioeconomic and political conditions suggest that on balance the amount of protection should increase in many countries, driven by economic prosperity, and by 2030 global land protection is forecast to reach 15–29%. The limiting factor in land protection varies among countries, and sub-Saharan African countries in particular will remain a very hard place for land protection because of low per-capita GDP. Overall, however, more land protection may occur in the next 20 years than has occurred in the previous 20 years. 相似文献
16.
福建省基于自适应调整的水稻生产对未来气候变化的响应 总被引:1,自引:0,他引:1
将福建省划分为3 个稻区, 共选取17 个样点和9 个代表性品种开展气候变化影响评价研究。首先, 根据IPCC排放情景特别报告(SRES)中的A2、B2、A1B 三种方案和区域气候模式(PRECIS), 生成了研究区域两个时段(1961-1990 年, 2021-2050 年)的气候变化情景; 然后, 采用经验证的CERES-Rice 模型, 模拟分析了福建省各稻区在未来不同气候变化情景下可能的稻作制度、品种搭配及水稻播期, 并认为这是水稻生产自适应调整后的结果; 接着, 以调整后的稻作制度、品种搭配及水稻播期作为CERES-Rice 模型新的输入, 在3 种气候变化情景下再次进行模拟试验, 最后得出未来经过自适应调整后的水稻产量、稳产性以及全省水稻总产的变化。结果表明: 在A2、B2、A1B 三种气候变化情景下, 闽东南双季稻区的早稻模拟产量经自适应调整后, 较之不考虑这种调整依次提高了15.9%、18.0%和19.2%, 后季稻依次提高了9.2%、7.4%和7.4%; 闽西北双季稻区的早稻模拟产量依次提高了21.2%、20.5%和18.9%, 后季稻依次提高了14.7%、14.8%和7.2%。考虑自适应调整后, 闽西北山地单季稻区的水稻模拟产量在A2、B2、A1B 情景下, 较之不考虑这种调整依次增产4.9%、5.0%和2.9%, 其中长汀在A2 与B2 情景下可改种双季稻。在综合考虑水稻生产自适应调整后, 福建省水稻模拟总产表现为增产, 在A2、B2 与A1B 情景下较之当前依次增加5.9%、5.2%和5.1%。因此,在气候变化影响评价研究中, 将水稻生产的自适应能力考虑在内, 不仅科学合理, 而且可以得到较为乐观的结论。 相似文献
17.
选择福建省作为研究区域,根据地形特点划分了3个水稻种植区,选取17个样点及9个代表性品种,采用2006—2007年的逐日气象资料及同期区试产量资料对作物的遗传参数进行了调试;根据IPCC排放情景特别报告(SRES)中的A1B方案,利用区域气候模式PRECIS构建的气候变化情景文件与作物模型(CERES-Rice)耦合,采用雨养与灌溉两种方式,并综合考虑未来CO2浓度增加带来的直接增益效应,模拟了未来2020s及2040s气候变化对福建省水稻生产的影响。结果表明:无论是雨养方式还是灌溉方式,未来全省各稻区水稻生育期在两种情景下都将缩短,单季稻生育期天数减少幅度最大,2040s情景下达到20 d以上。未来双季稻种植区早稻与单季稻均表现为减产。2020s情景下闽东南稻区早稻减产率达到12.4%(雨养)和11.3%(灌溉);闽西北双季稻区早稻减产程度略小。单季稻区雨养水稻7.1%及灌溉水稻2.1%的减产主要来自中熟品种的负贡献。2040s减产幅度将进一步加大。与此相反,未来两种情景下双季稻区后季稻均表现为增产,但产量波动性较大。2020s情景下闽西北双季稻区灌溉后季稻产量增产达到21.0%,增产幅度大于闽东南地区的10.6%;雨养方式下后季稻增产幅度略小。2040s各稻区后季稻增产幅度将减小。未来水稻生长季的土壤水分条件将变得不如目前湿润,与之相关各稻区灌溉需要量均有所增加。总之,由于大气CO2肥效作用可在一定程度上提高未来气候变化下后季稻产量,全省水稻总产近期将有所增加,雨养与灌溉方式下分别增长0.4%及1.7%,但变化趋势是随着未来温度的增加总产将减少,负贡献主要来自于单季稻和早稻。 相似文献
18.
山东省森林碳储量调查研究 总被引:1,自引:0,他引:1
森林作为陆地上的重要碳库,在调节气候,吸收大气中的二氧化碳,降低温室气体浓度等方面发挥着巨大的作用。山东省于2013年结合全国林业碳汇计量监测体系建设,开展了山东省森林碳汇专项调查,主要针对地上、地下、枯死木、枯落物和土壤5个碳库展开调查。共设置194个调查样地,经调查计算发现:山东省森林碳储量总量呈现逐年增加态势,至2012年,全省森林碳储量达到10524.85万t;在各碳库所占比重中,乔木层碳储量比重最大,其次为土壤碳储量,枯死木所占比重最小;除土壤碳库稳定不变,疏林碳储量呈现减少趋势外,其余碳库均呈现逐年增加趋势。 相似文献
19.
This paper reports on the net carbon flux caused by deforestation and afforestation in India over the period from 1982 to 2002, separately for two time periods, 1982–1992 (PI) and 1992–2002 (PII), using the IPCC 2006 guidelines for greenhouse gas inventories. The approach accounts for forest and soil C pool changes for (a) forest areas remaining as forests, (b) afforested areas and (c) deforested areas. The data set used were remote sensing based forest cover for three time periods (1982, 1992, 2002), biomass increments, biomass expansion factors and wood density. In addition a number of required coefficients and parameters from published literature were adopted. In the 1982–2002 period, the forest cover changed from 64.20 Mha in 1982 to 63.96 and 67.83 Mha in 1992 and 2002 respectively. During the PI and PII periods, plantations were also established of 0.2 and 0.5 Mha yr−1, while the annual deforestation rate was about 0.22 and 0.07 Mha in these periods, respectively. 相似文献
20.
中国农田管理土壤碳汇估算 总被引:39,自引:5,他引:39
【目的】长期大规模翻耕和秸秆燃烧造成土壤有机质(SOM)大量损失,使农田成为温室气体的一个排放源。然而,近年来,随着免耕技术的逐步推广、秸秆还田面积的增加,加上施肥、灌溉等农田管理措施的应用,农田土壤有机碳(SOC)储量有所回升,预计其将成为温室气体的吸收汇。本文通过分析各种农田管理措施下土壤有机碳(SOC)的变化量,估算中国农田管理土壤碳汇量,为制定中国农田温室气体清单提供科学参考。【方法】通过查阅相关文献著作等,构建农田管理情景,分析各管理措施长期定位试验土壤有机碳变化量的数据。根据中国农作制的分区,估算各区域及水田、旱地农田管理下的碳汇量,并与政府间气候变化专门委员会(IPCC)制定的2006IPCC国家温室气体排放清单指南中农田仍为农田的层次(Tier)2方法的估算结果进行比较。最后用Meta分析法估算中国农田管理土壤碳汇量。【结果】不同农田管理措施对土壤碳的影响不同。各种措施表现为化肥与有机肥配施的增碳作用最大,达到0.889 tC•ha-1•a-1;其次为秸秆还田、施有机肥和免耕,分别为0.597、0.545、0.514 tC•ha-1•a-1;施化肥的作用最不明显,仅为0.129 tC•ha-1•a-1。这一结果明显高于IPCC Tier2方法估算的结果。研究还揭示,不同管理措施在不同区域对土壤有机碳变化的影响存在一定的差异,黄淮海区、长江上中游区和西南区增加量较大,东北区增加量较小,在施化肥条件下东北黑土SOC甚至有降低的趋势。土壤有机碳的年增长率和初始值之间呈很好的负相关,由此可得出不同管理措施下农田土壤有机碳的平衡值及固碳潜力。【结论】农田管理措施中,配施、秸秆还田、施有机肥和免耕可以在很大程度上提高土壤SOC含量。其中,配施和秸秆还田的固碳潜力较大。 相似文献