全球农作物对大气CO2及其倍增的吸收量估算

根据农作物产量资料（ＦＡＯ１９９２年），计算出中国和全球各种作物对ＣＯ２的吸收总量分别为５．５×１０８ｔ／ａＣ和２８．９×１０８ｔ／ａＣ。同时以不同ＣＯ２浓度下小麦、玉米、大豆等全生育期光合速率实验数据直接计算的Ｃ吸收量为对照，与相应的中国产量资料计算结果比较，两者相差２．６％。从而进一步依据作物对ＣＯ２倍增反应诊断实验结果，推算出大气ＣＯ２浓度比目前倍增（７００ｐｐｍ）条件下，中国和全球农作物吸收ＣＯ２总量将增长２１％－２６％，分别为６．６×１０８ｔ／ａ—６．９×１０８ｔ／ａ和３４．１×１０８ｔ／ａ—３６．２×１０８ｔ／ａＣ。研究还表明，单位面积作物年吸Ｃ量全球（３．２ｔ／（ｈｍ２·８））比中国（４．２ｔ／（ｈｍ２·ａ））低２５．４％，而且Ｃ４作物普遍高于同类Ｃ３作物。     

气候变化对江苏省小麦生产的可能影响

根据国内外研究结果综合分析,得到ＣＯ２倍增时江苏省温度、降水的变化值,初步确定了ＣＯ２倍增时江苏省小麦生长季内的可能气候情景。分析未来ＣＯ２倍增时对小麦作物的直接影响、间接影响及紫外辐射影响。具体估算了温度升高、降水增加、ＣＯ２浓度上升、紫外辐射增强后江苏省小麦生育期不变和生育期缩短两种情景下的气候生产潜力,并由此分析了气候变暖对江苏省不同地区的利弊影响。结果表明：江北大部分地区小麦产量有所增加,     

CO2对温棚蔬菜的增产效应

Ｃ３作物对ＣＯ２最敏感。蔬菜属Ｃ３作物。由于日光温室、塑料大棚蔬菜生产环境基本上封闭，ＣＯ２浓度不足，远不能满足作物光合作用需要，使作物处于饥饿状态。在温棚中增施ＣＯ２，可使蔬菜长势旺盛，病害减轻，花期、结果期、采收期提前，产量大幅度提高。实验结果表明：９ｈ３０ｍｉｎ￣１０ｈ３０ｍｉｎ为最佳施用时间；定植活根后１５￣２０天、作物花芽分化和果实膨化时施用效果最佳；西红柿、黄瓜和西葫芦、芹菜，ＣＯ２浓     

O_3浓度变化对我国主要作物产量的可能影响

该文介绍了Ｏ＿３浓度变化对农作物的影响机制，如Ｏ＿３对作物光合与呼吸、生理生化过程和代谢物质、细胞透性、体内各类醇、组织器官以及其它功能的影响，根据美国ＮＣＬＡＮ近１０年的试验资料建立的Ｏ＿３浓度与作物产量的准线性关系，推算和评价了Ｏ＿３浓度变化对我国主要作物产量的可能影响。     

O3浓度变化对我国主要作物产量的可能影响

该文介绍了Ｏ３浓度变化对农作物的影响机制，对Ｏ３对作物光合与呼吸、生理生化过程和代谢物质、细胞透性、体内各类酶、组织器官以及其它功能的影响，根据美国ＮＣＬＡＮ近１０年的试验资料建立的Ｏ３浓度与作物产量的准线性关系，推算和评价了Ｏ３浓度变化对我国主要作物产量的可能影响。     

冬暖式塑料大棚小气候条件的研究

利用连续三年（１９９３～１９９５年）对冬暖式塑料大棚系统观测的小气候资料及生物学资料,分析了大棚内主要气象要素的变化规律及其与作物生长发育的关系。结果表明：（１）棚内温度日变化范围在１１～３０℃内,基本适合蔬菜生长发育对温度的要求;（２）影响蔬菜生长发育及产量形成的主要因子是棚内的光照强度,光照时间及ＣＯ２浓度;（３）通过改善棚内的光照条件和ＣＯ２施肥等措施,可明显提高蔬菜的产量和品质。     

CO_2浓度倍增对大豆叶片和总生物量的影响研究

该文利用ＯＴＣ－１型开顶式气室中进行的ＣＯ＿２浓度倍增对大豆影响的试验资料，详细分析了当大气中ＣＯ＿２浓度倍增时，对大豆叶片和总生物量的影响情况，并对大豆总生物量的时间动态变化进行了模拟。结果表明，当大气中ＣＯ＿２浓度倍增时，大豆全生育期将缩短，３叶和分枝的ＤＶＳ值变大，而结荚和鼓粒的ＤＶＳ值变小；总生物量和绿叶重增加显著，但在同一个ＤＶＳ值时，绿叶率（ＧＲ）、黄叶率（ＹＲ）的差异不明显；大豆的总生物量变化均遵循自然增长曲线，且处理和对照有极好的线性正相关关系；总生物量的积温当量提高，并且使大豆总生物量的最大积温当量出现的时间推迟，有利于植株积累更多的营养物质。     

区域气候模式对温室效应引起的中国地区气候变化的数值模拟

利用基于 ＲｅｇＣＭ２的区域气候模式并单向嵌套澳大利亚 ＣＳＩＲＯ Ｒ２１Ｌ９全球海－气耦合模式，进行了温室气体二氧化碳浓度倍增对中国气候变化影响的数值试验研究。控制试验结果表明：区域模式由于具有较高的分辨率，因而对中国区域地面气温和降水的模拟效果较全球模式有了较大提高；模式对 ２×ＣＯ２敏感性试验结果表明了在 ＣＯ２浓度倍增情况下，由于温室效应，中国区域的地面气温将有明显升高，降水也将呈增加趋势。     

气候变化对小麦生产影响的数值模型研究

在未来气候变化对作物影响的研究基础上,分析未来不同气候情景对南京地区小麦生长发育、产量形成的影响,并考虑了紫外辐射变化的影响。采用数值模拟方法具体估算了温度升高、降水变化、ＣＯ２ 浓度上升及紫外辐射增强对南京地区小麦产量的影响。计算结果表明：未来ＣＯ２ 增加可提高小麦产量,气温升高、降水变化及紫外辐射增强均使得小麦产量有所降低。     

海气耦合随机动力模式的Fokker—Planck方程

将描写海温和气温交互作用的随机动力模式化为一个Ｆｏｃｋｋｅｒ－Ｐｌａｎｃｋ方程（ＦＰＥ），然后用矩阵连分法进行求解，并对二氧化碳增温效应进行了计算。当ＣＯ２从３３０ｐｐｍ增加到６６０ｐｐｍ时增温１．２℃，模式中存在的优势周期为３￣４年，当ＣＯ２倍增时各周期有延长的趋势。     

How is CO2 affecting yields and technological progress? A statistical analysis

This paper analyzes the impact of climate, crop production technology, and atmospheric carbon dioxide (CO₂) on current and future crop yields. The analysis of crop yields endeavors to advance the literature by estimating the effect of atmospheric CO₂ on observed crop yields. This is done using an econometric model estimated over pooled historical data for 1950–2009 and data from the free air CO₂ enrichment experiments. The main econometric findings are: 1) Yields of C3 crops (soybeans, cotton, and wheat) directly respond to the elevated CO₂, while yields of C4 crops (corn and sorghum) do not, but they are found to indirectly benefit from elevated CO₂ in times and places of drought stress; 2) The effect of technological progress on mean yields is non-linear; 3) Ignoring atmospheric CO₂ in an econometric model of crop yield likely leads to overestimates of the pure effects of technological progress on crop yields of about 51, 15, 17, 9, and 1 % of observed yield gain for cotton, soybeans, wheat, corn and sorghum, respectively; 4) Average climate conditions and climate variability contribute in a statistically significant way to average crop yields and their variability; and 5) The effect of CO₂ fertilization generally outweighs the effect of climate change on mean crop yields in many regions resulting in an increase of 7–22, 4–47, 5–26, 65–96, and 3–35 % for yields of corn, sorghum, soybeans, cotton, and wheat, respectively.     

Effects of Climate Change on Carbon Storage in Boreal Forests of China: A Local Perspective

The BIOME3 model was used to simulate the distribution patterns and carbon storage of the horizontal, zonal boreal forests in northeast and northwest China using a mapping system for vegetation patterns combined with carbon density estimates from vegetation and soils. The BIOME3 prediction is in reasonable good agreement with the potential distribution of Chinese boreal forests. The effects of changing atmospheric CO₂ concentration had a nonlinear effect on boreal forest distribution, with 3.5–10.8% reduced areas for both increasing and decreasing CO₂. In contrast, the increased climate together with and without changing CO₂ concentration showed dramatic changes in geographic patterns, with 70% reduction in area and disappearance of almost boreal forests in northeast China. The baseline carbon storage in boreal forests of China is 4.60 PgC (median estimate) based on the vegetation area of actual boreal forest distribution. If taking the large area of agricultural crops into account, the median value of potential carbon storage is 6.92 PgC. The increasing (340–500 ppmv) and decreasing CO₂ concentration (340–200 ppmv) led to decrease of carbon storage, 0.33 PgC and 1.01 PgC respectively compared to BIOME3 potential prediction under present climate and CO₂ conditions. Both climate change alone and climate change with CO₂ enrichment (340–500 ppmv) reduced largely the carbon stored in vegetation and soils by ca. 6.5 PgC. The effect of climate change is more significant than the direct physiological effect of CO₂ concentration on the boreal forests of China, showing a large reduction in both distribution area and carbon storage.     

Effects of temperature rise and increase in CO2 concentration on simulated wheat yields in Europe

A crop-growth-simulation model based on SUCROS87 was used to study effects of temperature rise and increase of atmospheric CO₂ concentration on wheat yields in several regions in Europe. The model simulated potential and water-limited crop production (growth with ample supply of nutrients and in the absence of damage by pests, diseases and weeds). Historic daily weather data from 13 sites in Western Europe were used as starting point.For potential production (optimal water) a 3 °C temperature rise led to a yield decline due to a shortening of the growing period on all locations. Doubling of the CO₂ concentration caused an increase in yield of 40% due to higher assimilation rates. It was found that effects of higher temperature and higher CO₂ concentration were nearly additive and the combination of both led to a yield increase of 1–2 ton ha^-1. A very small CO₂-temperature interaction was found: the effect of doubled CO₂ concentration on crop yield was larger at higher temperatures. The inter-annual yield variability was hardly affected.When water was limiting crop-production effects of temperature rise and higher CO₂ levels were different than for the potential production. Rise in temperature led to a smaller yield reduction, doubled CO₂ concentration to a larger yield increase and combination of both led to a large yield increase (3 ton ha^-1) in comparison with yields simulated for the present situation. Both rise in temperature and increase in the CO₂ concentration reduced water requirements of the crop. Water shortages became smaller, leading to a reduction in inter-annual variability. It is concluded that when no major changes in precipitation pattern occur a climate change will not affect wheat yields since negative effects of higher temperatures are compensated by positive effects of CO₂ enrichment.     

Sensitivity of crop yields and land resource potential to climatic change in Ontario,Canada

Increasing concentrations of atmospheric CO₂ and other greenhouse gases are expected to contribute to a global warming. This paper examines the potential implications of a climatic change corresponding to a doubling of atmospheric concentrations of CO₂ on crop production opportunities throughout Ontario, a major food producing region in Canada. The climate is projected to become warmer and drier, but the extent of these shifts are expected to vary from region to region within Ontario. The effect of this altered climate on crop yields and the area of land capable of supporting specific crops varies according to region, soil quality and crop type. Most notable are the enhanced opportunities for grains and oilseeds in the northern regions, and the diminished production prospects for most crops in the most southerly parts of Ontario.     

Impacts of a Ghg-Induced Climate Change on Crop Yields: Effects of Acceleration in Maturation, Moisture Stress and Optimal Temperature

The present study involves using the Canadian Climate Centre (CCC) climate change scenario to evaluate the impacts of a CO₂-induced climate change on agriculture in Québec and vicinity. Climate change using the CCC General Circulation Model (GCM) data are fed into a crop model (FAO) so as to gauge the changes in agroclimatic factors such as growing season length and growing degree days, and subsequently potential yield changes for a variety of cereal (C₃ and C₄), leguminous, oleaginous, vegetable and special crops, for twelve major agricultural regions in southern Québec. Our results show that depending upon the agricultural zone and crop type, yields may increase (ex. corn and sorghum by 20%) or decrease (ex. wheat and soybean by 20 to 30%). Also, these crop yield changes appear to be related to acceleration in maturation rates, mainly to change in moisture stress and to shifts in optimal thermal growth conditions. These possible shifts in agricultural production potentials would solicit the formulation of appropriate adaptation strategies.     

Modelling climate change impacts on maize growth and development in the Czech Republic

Summary The crop growth model CERES-Maize is used to estimate the direct (through enhanced fertilisation effect of ambient CO₂) and indirect (through changed climate conditions) effects of increased concentration of atmospheric CO₂ on maize yields. The analysis is based on multi-year crop model simulations run with daily weather series obtained alternatively by a direct modification of observed weather series and by a stochastic weather generator. The crop model is run in two settings: stressed yields are simulated in water and nutrient limited conditions, potential yields in water and nutrient unlimited conditions. The climate change scenario was constructed using the output from the ECHAM3/T42 model (temperature), regression relationships between temperature and solar radiation, and an expert judgement (precipitation). Results: (i) After omitting the two most extreme misfits, the standard error between the observed and modelled yields is 11%. (ii) The direct effect of doubled CO₂: The stressed yields would increase by 36–41% in the present climate and by 61–66% in the 2 × CO₂ climate. The potential yields would increase only by 9–10% as the improved water use efficiency does not apply. (iii) The indirect effect of doubled CO₂: The stressed yields would decrease by 27–29% (14–16%) at present (doubled) ambient CO₂ concentration. The increased temperature shortens the phenological phases and does not allow for the optimal development of the crop. The simultaneous decrease of precipitation and increase of temperature and solar radiation deepen the water stress, thereby reducing the yields. The reduction of the potential yields is significantly smaller as the effect of the increased water stress does not apply. (iv) If both direct and indirect effects of doubled CO₂ are considered, the stressed yields should increase by 17–18%, and the potential yields by 5–14%. (v) The decrease of the stressed yields due to the indirect effect may be reduced by applying earlier planting dates. Received March 9, 2001 Revised September 25, 2001     

Effects of changes in temperature and CO2 concentration on simulated spring wheat yields in The Netherlands

A crop growth simulation model based on SUCROS87 was constructed to study the effects of temperature rise and increase of the atmospheric CO₂ concentration on spring wheat yields in The Netherlands. The model simulated potential production (limited by crop characteristics, temperature and radiation but without any stress from water or nutrient shortages or pests, diseases and weeds) and water-limited production in which growth is also limited by water shortage. The model was validated for the present climatic conditions. When daily weather data from a nearby station were used, the model was well able to simulate yields obtained in field experiments.Effects of several combinations of temperature rise and atmospheric CO₂ concentration on simulated yields were studied. A temperature rise resulted in a reduction in simulated yield due to shortening of the growing period. Large variations existed in the magnitude of this reduction. Increases in atmospheric CO₂ concentration led to yield increases due to higher assimilation rates and to increase of the water use efficiency. Combination of temperature rise and higher CO₂ concentration resulted in small yield increases in years in which water was not limiting growth and large yield increases in dry years.Change of variety or of sowing date could not reduce the negative effects of temperature rise on simulated yields.     

Relations between Light Hydrocarbon, Carbon Monoxide, and Carbon Dioxide Concentrations in the Plume from the Combustion of Plant Material in a Furnace

To systematically explain relations between light hydrocarbons, CO, and CO₂ concentrations/emissions of biomassburning, we measured concentrations/emissions of carbon gases – CO,CO₂, light hydrocarbons (CH₄, C₂H₆,C₂H₄, C₂H₂, C₃H₈, C₃H₆,n-C₄H₁₀, i-C₄H₁₀, n-C₅H₁₂,i-C₅H₁₂), and THC (total hydrocarbon) – in the burning of dead plant material, mainly Imperata grass, byclosed-chamber experiments and by time-series analyses of gas concentrations in combustion plumes in relatively efficient and inefficient combustion situations. Concentrations of hydrocarbons measured were well correlated to [CO] although [C₂H₂] was exceptionally well correlated to[CO₂]. The phase diagrams (relation between [CO]/ [CO₂] and [hydrocarbon]/ [CO₂]) obtained by the time-seriesexperiments well illustrated the variation in the overall emission rates of the closed-chamber experiments. The higher rates of decrease in hydrocarbon concentration with increasing carbon number in the efficient case compared with the inefficient case probably reflected the rate of oxidation and the amount of radicals. The overall concentrations (or emissions) of C₂H₄ and C₃H₆ were higher thanthose of C₂H₆ and C₃H₈, suggesting a linkage to mechanisms in whichthe predominant path of hydrocarbon oxidation is through the degradation of alkyl radicals, which can be immediately converted into or formed from alkenes. For C₃ and C₄ species, normal-chain species hadhigher emissions than iso-chain species under lower combustion efficiency. This may be attributable to the presence of tertiary C–H bonds in iso-species,which show more reactivity in the abstraction of H than secondary C–H bonds unless the carbon number is large.     

Influence d'un changement climatique dû à une hausse de gaz à effet de serre sur l'agriculture au quebec

Abstract

This study, using a climate change scenario generated by the Canadian Climate Centre (CCC) general circulation model (GCM) examines the impacts of such a climate change on agriculture in southern Quebec. Using a crop model from the Food and Agriculture Organization (FAO), yield responses of a variety of cereals, legumes, oleaginous and special crops to climate change are analysed and discussed.

Results show that under the 2 × CO₂ climate scenario the growing season would be longer and accumulation of corn heat units and growing degree days would be more important than under actual climate (1961–1990). One of the more important results of this study is that, on the one hand yield of C₃ cereals would be lower and that of C₄ cereals higher in most agricultural regions. On the other hand, the direct fertilisation effect of increased CO₂ is not considered. It must be cautioned however that we can not generalise results obtained for one legume crop to all legumes.