稻田甲烷排放的卫星遥感监测试验

1996至1997年5～9月在吉林省万昌试验区，利用箱式技术对水稻田甲烷（CH4）排放通量进行观测，取得了两个完整的水稻生长期内CH4排放资料，并收取了同期美国NOAA气象卫星资料，用陆地卫星专题图仪（TM）与气象卫星甚高分辨率扫描辐射计（AVHRR）数值计算研究区水稻种植面积，并通过遥感水稻空间长势，为各生育期的水稻做植被指数（Iv）分析结果表明，Iv与稻田CH4排放通量具有显著的相关关系，而亮温则不能作为CH4排放的指标因子。建立Iv与稻田CH4排放的关系，可计算出研究区域稻田CH4排放总量。     

INTEX-B NO2排放源在中国地区的应用与检验

将INTEX-B排放源应用到空气质量模型Model3-CMAQ中,对中国地区对流层NO₂的浓度分布进行了数值模拟,并与OMI卫星对流层NO₂资料进行了对比和验证。结果表明：将INTEX-B排放源应用到Model3-CMAQ模式,模拟的NO₂浓度在中国地区的分布、季节变化规律与卫星资料所得结果一致。敏感性试验表明,工业及电厂排放对NO₂的浓度贡献最大,而交通排放的贡献相对较小,两种排放均主要集中在京津、长江三角洲等经济发达地区。     

中国稻田甲烷产生和排放研究 Ⅰ.产生和排放机理及其影响因子

综合论述了近 2 0年来中国稻田甲烷排放的研究状况 ,包括中国稻田甲烷排放通量的观测 ,稻田甲烷生成的生物学机理及产生、转化、传输的机理研究 ,稻田甲烷排放的影响因子 ,主要介绍了稻田甲烷产生和氧化过程、影响甲烷排放的因子     

气象因子对里下河地区白皮小麦种植的影响

红皮小麦一直是里下河地区夏收的主要作物。随着农作物种植结构的调整及国家有关小麦收购政策的出台 ,白皮小麦逐渐受到人们的关注。地处里下河地区的宝应县 1 998年进行了小面积的白麦试种 ,取得初步成功。1 999年秋播白麦种植面积扩大到 6 70 0 hm2 ,但到今年小麦成熟收割期由于遇到持续性降水 ,导致严重的穗粒发芽 ,几乎绝收 ,农民损失惨重。本文试图通过白麦的品种特性和白麦成熟期里下河地区的气候条件分析 ,探讨江苏里下河地区白皮小麦发展的前景。1　白皮小麦的品种特性　　白皮小麦又称面包小麦 ,其面筋含量高 ,品质好 ,销售价格高 …     

我国杭州地区秋和稻田的甲烷排放

1987年秋季在杭州郊区采用一套全自动的观测系统,对稻田的甲烷排放进行了观测。在整个晚稻灌溉期内,稻田是大气甲烷的一个源地,其甲烷释放率最高可达240mg/m~2·h。甲烷释放率具有很强的季节性变化,在水稻成熟期之前,甲烷释放率一般在40-60mg·CH_4/m~2·h的水平上波动,在成熟期间则降为10mg·CH_4/m~2·h的水平。除移栽期外的整个水稻生长期间的甲烷平均释放率为39mg/m~2·h。甲烷释放率具有明显的日变化,一般在午夜至凌晨3—4点达最大值,白天较低,变化也较小。这可能与水稻植物体由于其生理上的日变化引起的甲烷气体传输能力的日变化有关。实验没有观测到不同施肥(K_2SO_4和菜饼)对甲烷释放率的明显影响。阴雨天的降温一般在2—3天后引起甲烷释放率的迅速下降,这可能是因土壤中发酵细菌如产甲烷菌数量的减少造成的。尽管甲烷释放率和土壤温度在整个生长期间基本上是逐步下降的,但两者之间并没有简单的正相关性。土壤中产生的甲烷气体只有一小部分释放到大气中,从土壤中冒出来的气泡往往可引起释放率的急剧上升。1985年全球稻田的甲烷释放量估计为134±3lTg(1Tg=10~(12)g),其中12±26Tg和30±6Tg分别来自亚太地区和中国稻田。     

东宁气候要素对水稻种植的影响

1自然环境 东宁县位于黑龙江省东南部,属牡丹江市所辖的边境县份,境内总面积7137 km2,地貌呈＂九山半水半分田＂特征。受海洋性气候影响,东宁气候温和四季分明,雨热同季,水量充沛,素有＂塞北江南＂之美誉。东宁盆地,西起东宁县城向东延伸,一直到瑚布图河,都是冲积平川。     

中国南京与美国德克萨斯稻田甲烷排放的比较

Field measurements of methane emission from rice paddies were made in Nanjing, China and in Texas, USA, respectively. Soil temperature at approximately 10 cm depth of the flooded soils was automatically recorded. Aboveground biomass of rice crop was measured approximately every 10 days in Nanjing and every other week in Texas. Seasonal variation of soil temperature in Nanjing was quite wide with a magnitude of 15.3℃ and that in Texas was narrow with a magnitude of 2.9℃. Analysis of methane emission fluxes against soil temperature and rice biomass production demonstrated that the seasonal course of methane emission in Nanjing was mostly attributed to soil temperature changes, while that in Texas was mainly related to rice biomass production. We concluded that under the permanent flooding condition, the seasonal trend of methane emission would be determined by the soil temperature where there was a wide variation of soil temperature, and the seasonal trend would be mainly determined by rice biomass production if there are no additional organic matter inputs and the variation of soil temperature over the rice growing season is small.     

清远地区晚稻田甲烷排放的实验

根据2003年清远地区晚稻田甲烷(CH4)排放的实验观测资料,分析了该地区晚稻田生长期间CH4排放的变化规律,对影响排放的相关因子进行了分析。结果表明:晚稻田CH4排放的变化规律基本为3峰型,整个生长期间平均排放通量为6.09 mg.m-2.h-1。不同稻种之间的CH4排放通量差别不是很大,种植的2个水稻品种"金优99"和"七丝尖"相差1.08 mg.m-2.h-1。水位和土壤氧化还原电位对CH4排放通量有明显的影响。     

广东清远早、晚稻稻田甲烷排放的观测研究

分析了2003、2004年广东省清远市郊区早、晚稻稻田甲烷（CH4）的排放通量,结果表明：广东清远早、晚稻稻田CH4排放通量的几何平均值2003年为4,38mg·m^-2·h^-1和6．09mg·m^-2·h^-1;2004年为5．17mg·m^-2·h^-1和8．3mg·m^-2·h^-1,土壤有机质含量是造成2003和2004年CH4排放差异的原因之一。水稻品种的不同,CH4排放通量也有所不同,实验表明,水稻品种“七丝尖”的排放通量比品种“金优99”高1．08mg·m^-2·h^-1,产量却只有64％。此外,与相关的测量结果进行初步比较。     

广东省不同地区稻田甲烷排放的差异性及其模型估计

减少温室气体排放以减缓全球变暖是当前全球变化研究的主要关注点。制定区域适应性的减排措施,有赖于对不同环境条件下温室气体排放空间差异性的进一步研究。广东是我国主要的双季稻种植区,其气候条件及稻田耕作方式都有别于我国其他稻区的。为估算广东省区域稻甲烷(CH_4)排放情况,利用IPCC2006清单指南中的稻田甲烷模型——CH_4MOD,模拟计算了2010年广东省21个地市双季早(晚)稻CH_4排放量及其排放因子。结果显示:1) 2010年稻田CH_4排放量为60. 74万t,其中双季晚稻CH_4排放量35. 01万t,双季早稻CH_4排放量25. 73万t。2)稻田CH_4排放量空间分布不均,区域稻田甲烷排放量为粤西的粤北的珠江三角洲的粤东的,排放量分别为21. 22万t、17. 02万t、15. 14万t、7. 36万t。3)双季早稻CH_4排放因子明显小于晚稻的,双季早稻CH_4排放因子为261. 18 kg CH_4/hm~2,双季晚稻为358. 53 kg CH_4/hm~2。4)空间上,粤西地区稻田CH_4排放因子水平较高,粤北、粤东的处于中等水平,珠江三角洲稻田CH_4排放水平最低。     

Emission of nitrogen oxides (NO x ) from a flooded soil fertilized with urea: Relation to other nitrogen loss processes

Emissions of nitric oxide and other odd nitrogen oxides (NO _x ) from a flooded rice field were studied after urea had been broadcast into the floodwater.The NO _x flux from the fertilized area was very low (0.2×10^-9 g N m^-2 s^-1) for the first few days after application of urea and was high (0.95×10^-9 g N m^-2 s^-1) in the subsequent period when significant nitrite and nitrate were present in the floodwater. At night, little if any NO _x was exhaled but ambient NO₂ was absorbed by the floodwater. An uptake velocity for NO₂ of 3×10^-4 m s^-1 was measured during one night. Maximum NO _x losses were observed near 1300 h when temperature and solar ultraviolet light were maximum.While the amounts of nitrogen oxides emitted are of little agronomic importance (2×10^-3 per cent of the fertilizer nitrogen was lost as NO _x during the 10-day study period), they may well be of significance as a source for some gas reactions in the atmosphere and for the global nitrogen cycle.Of the fertilizer nitrogen applied (as urea) approximately 30% was lost to the atmosphere by NH₃ volatilization, 15% by denitrification, presumably as N₂, and the remainder, less minor losses of NO and N₂O, remained in the plant/soil/water system.Now at Forestry Department, Australian National University, G.P.O. Box 4, ACT 2601, Australia.