[精选]读书报告4土壤碳固定对全球气候变化和粮食安全的影响10257.pptx
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1、Soil Carbon Sequestration Impacts on Global Climate Change and Food SecurityTutor:Prof.ZHENGSpeaker:DongXiaogangDate:2012-05-10R.Lal,et al.2004 Science 304,1623土壤碳固定对全球气候变化和粮食安全的影响2.Soil Carbon Sequestration3.Soil Carbon Sequestration for Mitigating Climate Change4.Soil Carbon Sequestration and Glob
2、al Food Security5.Conclusions1.Background ContentThe global soil carbon(C)pool of 2500 gigatons(Gt)includes about 1550 Gt of soil organic carbon(SOC)and 950 Gt of soil inorganic carbon(SIC).1.BackgroundThe soil C pool is 3.3 times the size of the atmospheric pool(760 Gt)and 4.5 times the size of the
3、 biotic pool(560Gt,fig.S1).25000 亿吨的全球土壤碳库由15500 亿吨的土壤有机碳和9500 亿吨的土壤无机碳组成。土壤碳库的容量是大气碳库的3.3 倍,是生物碳库的4.5 倍。Fig.1.Processes affecting soil organic carbon(SOC)dynamics.The SOC pool represents a dynamic equilibrium of gains and losses(Fig.1).土壤碳库处于收支动态平衡。Severe depletion of the SOC pool degrades soil qua
4、lity,reduces biomass productivity,and adversely impacts water quality,and the depletion may be exacerbated by projected global warming.The depletion is exacerbated when the output of C exceedsthe input and when soil degradation is severe.当输出超过输入和土壤退化严重时土壤碳库的耗竭将加剧。土壤碳库的严重耗竭使得土壤质量退化,生物产量降低,影响水质量,预测的全球
5、变暖可能会加剧土壤碳库的耗竭。The estimates of historic SOC loss range widely,from 44 to 537 Gt,with a common range of 55 to 78 Gt(3).以往的土壤有机碳的损失量的估算值变化范围广大约从440 到5370 亿吨,而共识的损失量是550 到780 亿吨。2.Soil Carbon SequestrationCarbon sequestration implies transferring atmospheric CO2 into long-lived pools and storing it se
6、curely so it is not immediately reemitted.Thus,soil C sequestration means increasing SOC and SIC stocks through judicious land use and recommended management practices(RMPs).土壤碳固定意味着将大气中的CO2转移到长期存在的土壤库中并安全地储存它,因此使碳不能立即释放到大气中。因此土壤碳固定意味着通过精确的土地使用和推荐的管理措施(RMPs)增加了土壤有机和无机碳库的容量。The SOC sequestration is c
7、aused by those management systems that add high amounts of biomass to the soil,cause minimal soil disturbance,conserve soil and water,improve soil structure,enhance activity and species diversity of soil fauna,and strengthen mechanisms of elemental cycling(Fig.2,table S2).土壤有机碳的固定是由向土壤中增加高生物量,使土壤受到最
8、小的扰动,保持水土,提高土壤结构,增强土壤动物的种类和多样性的活性,增强元素循环而实现的。(Fig.2,table S2)2.Soil Carbon SequestrationFig.2.具有高的土壤碳固定潜能的态系统有:农田,放牧的草地,退化的或沙漠化土地,灌溉的土壤放牧的草地的生态系统的土壤碳固定潜力不包括在全球的土壤碳固定中,这是因为它部分的被覆盖在其它生态系统下以及具有很大的不确定性。Common RMPs that lead to SOC sequestration are mulch farming,conservation tillage,agroforestry and div
9、erse cropping systems,cover crops(Fig.3),and integrated nutrient management,including the use of manure,compost,biosolids,improved grazing,and forest management.通常导致土壤有机碳固定的RMPs 措施是:覆盖农业,保护性耕作,混农林和多样性种植系统(Fig.3),和包括由粪肥、堆肥、生物固体、改善的放牧模式和林地管理的使用的综合养分管理。2.Soil Carbon SequestrationFig.3.Important recomme
10、nded management practices are no-till farming,cover crops,manuring and agroforestry.(A:Long-term no-till plots B:Agroforestry)The rate of SIC sequestration as secondary carbonates is low(5 to 150 kg C/ha per year)and is accentuated by biogenic processes and leaching of carbonates into the groundwate
11、r(11,12),especially in soils irrigated with water containing low carbonates.作为处于次要地位的碳酸盐,土壤无机碳的固定的速率是很低的(每年5 到150kgC/ha),土壤无机碳作为生命必须的过程和碳酸盐向地下水的淋洗过程被重视,(11,12)特别是在含有低碳酸盐的水中的土壤灌溉区。2.Soil Carbon Sequestration土壤无机碳的固定3.Soil Carbon Sequestration for Mitigating Climate Change 土壤碳固定对气候变化的缓解Estimates of th
12、e total potential of C sequestration in world soils vary widely from a low of 0.4 to 0.6 Gt C/year(9)to a high of 0.6 to 1.2 Gt C/year(13).Thus,the potential is finite in capacity and time.Nonetheless,soil C sequestration buys us time until the alternatives to fossil fuel take effect.Some issues rel
13、ated to this strategy are as follows:全球土壤碳固定总的潜力的估算值是非常广泛的,从低的0.4 to 0.6 Gt C/year(9)到高的0.6 to 1.2 Gt C/year(13)。因此,这种固定的潜力在容量和时间上是有限的。尽管如此,直到我们能找到化石燃料的替代品时,土壤碳固定为我们争取了时间。(1).Agricultural chemicals 农化用品Most RMPs involve C-based input.Item(1 Kg)Need C(Kg)N 0.86P2O50.17K2O 0.12Lime 0.36Herbicides 4.7F
14、ungicides 5.2Insecticides 4.9However,inputs are needed not for soil C sequestration per se,but for increasing food production and ensuring sustainable use of soil and water resources.(1).Agricultural chemicals然而输入不仅是为了土壤碳固定自身,也是增加了粮食生产,确保水土资源使用的可持续。(2).Nutrients required 养分需求It is estimated that seq
15、uestration of 1 Gt of C in world soils would require 80 million tons(Mt)of N,20 Mt of P,and 15 Mt of K.In comparison,the global fertilizer use in 2000 was 136 Mt(17).据计算,世界土壤中10 亿吨的碳固定需要8000 万吨的N,2000 万吨的P,1500 万吨的K。与此相比,2000 年全球肥料的施用量为1.36 亿吨(17)。One ton of cereal residue contains 12 to 20 kg N,1 t
16、o 4 kg P,7 to 30 kg K,4 to 8 kg Ca,and 2 to 4 kg Mg.Annually,3 Gt of residues of grain crops are produced globally(table S3),which if recycled rather than removed for fuel and other uses,would improve soil quality and sequester C.一吨的禾谷类作物残渣含有12 到20Kg 的N,1 到4Kg 的P,7 到30Kg 的K,4 到8Kg 的Ca 以及2 到4Kg 的Mg。每
17、年全球有30 亿吨的禾谷类作物残渣被生产(table S3),这些作物残渣如果是循环利用而不是用于燃料和其它方面的使用,将提高土壤质量和固定碳。(2).Nutrients requiredCrop residue is also a potential source of energy by direct combustion,or for production of ethanol or H2.It can be used either for biofuel production or to sequester C and improve soil quality.The economic
18、s of these two competing uses need to be assessed.作物残渣通过直接的燃烧也是能源的一个潜在的库,或者也可以作为乙醇或氢气的生产原料。作物残渣既可以用于生物燃料的生产或用于碳的固定以提高土壤质量。这二者的竞争使用的经济效益需要被评估。(3).Soil erosion and deposition 土壤的侵蚀和沉积The SOC is preferentially removed by wind-and water-borne sediments through erosional processes.Some of the SOC-enriche
19、d sediments are redistributed over the landscape,others are deposited in depressional sites,and some are carried into the aquatic ecosystems(Fig.1).Yet,an effective soil erosion control is essential to sustainable use of agricultural soils and improving environment quality.土壤有机碳是通过侵蚀过程优先被风传和水传沉淀的。一些
20、是在陆地在分布,一些是在作用位点被沉积,而另一些是被移动到水生生态系统中(Fig.1)。然而,一个有效的土壤的侵蚀的控制对于农业土壤的可持续使用和改善环境质量来说是很重要的。Fig.1.Processes affecting soil organic carbon(SOC)dynamics.(4).Extractive farming practices 传统的农业措施The annual depletion rate of nutrients for sub-Saharan Africa(SSA)caused by low-input/subsistence farming is estim
21、ated to be 40 kg of NPK/ha of cultivated land since the mid-1960s(20).Therefore,RMPs must enhance rather than deplete SOC pool and soil fertility,increase rather than maintain or decrease crop yield per unit use of fertilizer and other inputs,and improve rather than degrade soil quality.由于低投入或自给农业引起
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