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由人类活动所造成的大气中温室气体浓度急剧增加而引起的全球气候变暖和环境变化已引起全世界的广泛关注。氧化亚氮(N2O)是仅次于二氧化碳(CO2)和甲烷(CH4)的一种温室气体,在大气中含量较低却十分稳定,具有较大的增温潜能(其单分子的增温潜能是CO2的310倍)和较快的浓度增加速率(以每年0.25%的速率增加)(IPCC,2007)。N2O可吸收红外线,减少地球表面通过大气向外层空间的热辐射,导致地球表面温度增加。N2O能参与大气中许多光化学反应,破坏臭氧层(Crutzen,1970),导致到达地球表面的紫外线明显增加,给人类健康和生态环境带来多方面的危害。 相似文献
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温室气体是指大气中自然或人为产生的的气体成分,它们能够吸收和释放地球表面、大气和云发出的热红外辐射光谱内特定波长的辐射。该特性导致温室效应。水汽（H2O）、二氧化碳（CO2）、氧化亚氮（N2O）、甲烷（CH4）和臭氧（O2）是地球大气中主要的温室气体。此外,大气中还有许多完全人为产生的温室气体等,如卤烃和其它含氯和含溴的物质,六氟化硫（SF6）、氢氟碳化物（HFC）和全氟化碳（PFC）也定为温室气体。 相似文献
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随着CO2等温室气体的增加导致的全球气候变暖,严重影响了世界各国社会和经济的发展,因此,联合国气候变化框架公约谈判的不断深入,陆地中森林作为大气中吸收CO2的主体,起到缓解气候变暖的作用受到越来越多的关注。因此,2001年的《马拉喀什协定》和《波恩政治协议》将造林、再造林等林业碳汇项目,作为第一承诺期合格的清洁发展机制(CDM)项目。文章结合中国实际情况,针对我国林业碳汇的现状和发展趋势,进行了探讨和分析。 相似文献
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《绿色中国(A版)》2017,(8)
<正>20世纪以来的科学研究表明,全球气候正在发生有史以来从未有过的急剧变化,由于人类使用化石燃料排放的大量二氧化碳等温室气体导致大气增温效应明显加强,如果继续保持当前或高于当前的温室气体排放速率将会引起大气进一步变暖,到本世纪末,全球气温可能比工业化之前的时期升高5℃甚至更多。美国宇航局高级气候科学家、"全球气候变暖研究之父"詹姆斯·汉森指出:气候变化一旦达到临界点后,气候系统 相似文献
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福建省森林固碳制氧价值估算 总被引：2，自引：0，他引：2
森林固持二氧化碳、释放氧气,是生态服务的重要功能之一,在全球温室效应加剧的情况下,显得更为重要,森林资源在稳定气候方面发挥的作用,非常值得研究,森林资源固碳制氧对于维持人类的生存与发展具有重要意义。1森林的固碳制氧功能由于工业化革命的发展和世界人口的急剧增加,使温室气体的主要成分CO2的浓度逐年上升。据估计,到2050年,大气中CO2的浓度将达到550mg/kg。森林与温室气体有密切的关系。在陆地植物与大气中CO2的交换中,90%是由森林植被完成的。一方面森林通过光合作用吸收和固定大气中的CO2;另一方面森林的破坏使释放的CO2和其… 相似文献
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温室效应引起全球变暖和气候变化,影响社会经济的发展,危及人类的生存,是当今世界最重要的生态问题之一。减缓和控制这一过程的最重要的手段之一就是造林固碳。1温室气体与气候变暖包裹着地球表面的大气层中,含有少量的二氧化碳、甲烷等气体。它们含量虽低,但作用巨大。它们通过吸收地球反射的太阳能而温暖了大气,并稳定了地球表面的温度。这就是温室效应。《联合国气候变化框架公约》把温室气体定义为:“大气中那些吸收和重新放出红外幅射的自然和人为的气体。”其中主要成分是二氧化碳,约占温室气体总量的61%。温室气体的存在使地球表面的… 相似文献
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《绿色中国(A版)》2017,(2)
<正>20世纪以来的科学研究表明,全球气候正在发生有史以来从未有过的急剧变化,由于人类使用化石燃料排放的大量二氧化碳等温室气体导致大气增温效应明显加强。如果继续保持当前或高于当前的温室气体排放速率将会引起气候进一步变暖。到本世纪末,全球气温可能比工业化之前的时期升高5℃甚至更多。美国宇航局高级气候科学家、"全球气候变暖研究之父"詹姆斯·汉森指出:气候变化一旦达到临界点后, 相似文献
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Agroforestry systems may play an important role in mitigating climate change, having the ability to sequester atmospheric carbon dioxide (CO2) in plant parts and soil. A meta-analysis was carried out to investigate changes in soil organic carbon (SOC) stocks at 0–15, 0–30, 0–60, 0–100, and 0 ≥ 100 cm, after land conversion to agroforestry. Data was collected from 53 published studies. Results revealed a significant decrease in SOC stocks of 26 and 24% in the land-use change from forest to agroforestry at 0–15 and 0–30 cm respectively. The transition from agriculture to agroforestry significantly increased SOC stock of 26, 40, and 34% at 0–15, 0–30, and 0–100 cm respectively. The conversion from pasture/grassland to agroforestry produced significant SOC stock increases at 0–30 cm (9%) and 0–30 cm (10%). Switching from uncultivated/other land-uses to agroforestry increased SOC by 25% at 0–30 cm, while a decrease was observed at 0–60 cm (23%). Among agroforestry systems, significant SOC stocks increases were reported at various soil horizons and depths in the land-use change from agriculture to agrisilviculture and to silvopasture, pasture/grassland to agrosilvopastoral systems, forest to silvopasture, forest plantation to silvopasture, and uncultivated/other to agrisilviculture. On the other hand, significant decreases were observed in the transition from forest to agrisilviculture, agrosilvopastoral and silvopasture systems, and uncultivated/other to silvopasture. Overall, SOC stocks increased when land-use changed from less complex systems, such as agricultural systems. However, heterogeneity, inconsistencies in study design, lack of standardized sampling procedures, failure to report variance estimators, and lack of important explanatory variables, may have influenced the outcomes. 相似文献
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择伐对小兴安岭地区针阔混交林土壤呼吸温度敏感性的影响 总被引：1，自引：0，他引：1
利用LI8100土壤二氧化碳排放通量全自动测量系统,测定小兴安岭地区针阔混交林不同强度择伐后4年的林地土壤呼吸速率和土壤温度。运用Q10模型分析择伐后林地土壤呼吸速率对土壤温度的敏感性。结果表明:择伐后林地Q10值高于未采伐林地,较高强度(60%,71%)的择伐使土壤呼吸速率对土壤温度具有高的敏感性。这一现象是3个土壤各组分呼吸对土壤温度响应综合作用的结果。枯枝落叶层呼吸速率对土壤温度的敏感性较差,根呼吸速率和矿质土壤层呼吸速率对土壤温度的敏感性较高。 相似文献
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黄土高原地区柠条人工林土壤呼吸 总被引：4，自引：0，他引：4
2005—2008年用红外气体分析法测定柠条人工林地的土壤呼吸。结果表明:柠条林地土壤呼吸具有明显的日变化特征,最大值出现在14:00左右,最低值出现在凌晨;柠条林地3—12月的土壤呼吸总量为814.9～1224.7gC·m-2,表现出明显的季节变化和年际变化;土壤呼吸与土壤温度呈显著指数正相关,方程的决定系数R2为0.31～0.67,由拟合的指数方程系数计算出柠条林2005,2006,2007和2008年的Q10值分别为2.02,1.70,1.76和1.75,生长季和非生长季的Q10值分别为0.64和2.11;2005和2006年土壤呼吸速率与土壤水分呈极显著线性相关(P0.01),方程的决定系数R2在0.30左右,而2007和2008年则不显著(P0.05);生长季(5—9月)土壤水分起主要作用,可以解释土壤呼吸季节变化的55%,非生长季土壤温度起主要作用,可以解释土壤呼吸季节变化的37%;4个双因子模型可以解释土壤呼吸季节变化的51%～83%。 相似文献
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本文在不同立地类型土壤含水量调查的基础上,应用数量化理论Ⅰ建立了描述泥河沟流域土壤含水量与空间立地因子(坡度、森林、农地、荒坡、阳坡、阴坡)之间函数关系的模拟模型。利用遥感和地理信息系统技术,实现流域内土壤含水量空间立地因子分布规律的模拟。 相似文献
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滴灌条件下杨树人工林土壤的水分运移 总被引：3，自引：0，他引：3
采用田间土壤剖面观测法,对北京永定河故道沙地上地表滴灌栽培的杨树人工林的土壤水分运移规律进行研究,在滴头流量恒定为4 L·h-1的条件下,试验和测定不同滴灌时长和停灌后土壤湿润锋的运移距离和土壤湿润体的形态.结果表明:土壤湿润锋随着滴灌时长的增加在垂直和水平方向上的运移距离逐渐增大,每增加1h滴灌时长,土壤湿润锋的垂直运移距离的增幅逐渐减小,水平运移距离的增幅则大小不一;在各时长滴灌停灌后,土壤湿润锋将继续在垂直方向和水平方向上运移1～3h,在垂直方向上的继续运移距离为2～10 cm,除在土壤最深处的水平继续运移距离明显较大外,在各土壤深处水平方向上的继续运移距离为1 ～ 10 cm;在持续滴灌1～6 h后,土壤湿润锋最终可以垂直运移到36 ～ 69 cm,水平运移到32～57 cm,持续滴灌3～4h后即可在0～40 cm土层内形成以滴头为圆心,半径30～ 40 cm的土壤湿润体;持续滴灌1～3h后土壤湿润体形态为逐渐增大的扁半椭球体,持续滴灌4～6h后土壤湿润体形态为逐渐增大的长半椭球体. 相似文献
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An on-farm trial was conducted to determine dry matter production of four fodder tree species and their effect on soil water
and maize production. The trees were planted in rows intercropped with maize. The four tree species selected were Acacia karroo Hayne (indigenous fodder tree), Leucaena leucocephala (Lam.) De Wit (nitrogen fixing), Morus alba L. (fodder and fruit), and Gleditsia triacanthos L. (fodder and fuel). Volumetric soil water was measured in the upper 0.3 m of soil in each row of the trial using the time
domain reflectometry technique. The neutron probe technique was used for monitoring the water content deeper in the soil.
Geostatistical methods were used to analyse treatment differences in the upper 0.3 m of soil. The soil water content did not
differ significantly between the maize and tree rows indicating that competition for water in the upper horizon was not the
reason for lower maize yields. However, at greater soil depths (75–125 cm) trees in the wide spacing used less water than
those in the narrow spacing. Light interception was an important factor in reducing maize yields in the row nearest to the
trees. High soil water values recorded during summer indicated that in the current cycle of good rainfall the plants in the
agroforestry trial were not stressed. Thus the trees do not compete with the crops for soil moisture in good rainfall seasons.
However, this study would need further evaluation for the competition for water for the low rainfall years. Since the trees
have access to water at greater depths, they are likely to be more productive into the dry season than shallow rooted crops. 相似文献
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Susan Balaba Tumwebaze Eddie Bevilacqua Russell Briggs Timothy Volk 《Agroforestry Systems》2012,84(1):11-23
The objective of this study was to quantify and compare the amount and distribution of soil organic carbon (SOC) under a linear
simultaneous agroforestry system with different tree species treatments. Field work was conducted at Kifu National Forestry
Resources Research Institute in Mukono District, Central Uganda, in a linear agroforestry system established in 1995 with
four different tree species and a crop only control treatment. Soil samples were collected in 2006 at three depths; 0–25,
25–50, and 50–100 cm, before planting and after harvesting a maize crop. The results indicate that an agroforestry system
has significant potential to increase SOC as compared to the crop only control. There was no significant difference in the
amount of SOC under exotic and indigenous tree species. Among the exotic species, Grevillea robusta had higher SOC than Casuarina equisetifolia across the entire depth sampled. There is significant difference in SOC among the indigenous species, where Maesopsis eminii has more SOC than Markhamia lutea. Distance from the tree row did not significantly influence SOC concentration under any of the tree species. In selecting
a tree species to integrate with crops that will sequester reasonable quantities of carbon as well as boost the performance
of the crops, a farmer can either plant an exotic species or an indigenous. In this study, the soil under Grevillea robusta and Maesopsis eminii have the highest potential to store organic carbon compared to soil under other tree species. 相似文献
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加勒比松(Pinus caribaea Morelet)生长快、适应性强、耐瘠薄土壤,是南亚热带低海拔丘陵地区造林绿化的主要树种之一[1].由于纯松林结构简单、生态效益差[2],在纯松林下套种阔叶树进行改造,可以建成针阔混交林,为修复脆弱的生态系统提供了一条有效途径.土壤影响着林木的生长,土壤理化性质是土壤质量的重要指标[3-4],土壤微生物和酶在分解凋落物及土壤的生化循环中起重要作用[5-6],影响植物养分的吸收[7-10],二者越来越多地被用做土壤肥力的一个指标[6,11].由于土壤的物理、化学和生物性质相互作用,土壤质量应该结合物理的、化学的和生物的因子进行评价[12].森林凋落物是林地养分的主要来源,可以改变森林土壤的理化性质,并对土壤微生物产生影响. 相似文献
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Guifeng, Yiyang County, belongs to a seriously degraded red soil region. In 1991, Pinus elliottii and Lespedaza spp. were the species selected for the establishment of a mixed forest in the area. The results of an investigation of the
soil system in a 12-year-old forest indicated the following: (1) Organic matter and total nitrogen of the forest soil to a
depth of 40 cm were 88.0 and 36.0% higher, respectively, than those of a control plot; total phosphorus and available phosphorus
were 40.9 and 22.3% higher than those of the control; available potassium contents were 8.13% lower than those of the control.
(2) Soil aeration and the soil air regime improved. (3) Proteinase, catalase, and urease in the forest soil to a depth of
40 cm were usually higher than those in the control plot and decreased with soil depth.
Translated from Acta Agriculturae Universitatis Jiangxiensis, 2005, 27(1) (in Chinese) 相似文献