首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 468 毫秒
1.
气候变暖对宁夏引黄灌区水稻生产的影响   总被引:9,自引:5,他引:4  
桑建人  刘玉兰  邱旺 《中国沙漠》2006,26(6):953-958
对宁夏引黄灌区10个测站1961\_2004年水稻生长发育期5~9月的气温进行分析,结果表明,宁夏引黄灌区水稻生长期的气候明显变暖。t检验表明,5~9月日平均气温的突变发生在1993年,突变后的气温比突变前升高了0.8℃。在水稻生长发育各阶段,气温都有所升高,但没有超过水稻生长发育的适宜温度范围。引黄灌区水稻的温度敏感系数在5月、7~9月上旬为正值,尤其在7月下旬至8月中旬最大,此阶段气候变暖对水稻生产有利,6月、9月中下旬为负值,气候变暖对水稻生产有不利影响。气候变暖为高产品种的引进创造了条件,降低了水稻对温度变化的敏感性,使水稻单产变率减小,保证了水稻的高产稳产。就宁夏引黄灌区而言,气候变暖对水稻单产的贡献为2.51%。  相似文献   

2.
Rice is the main food crop in densely populated Bangladesh. Regional climatic variations can play an important role in rice productivity. For example, excessive heat or extremely cool conditions disrupt normal plant physiological processes and cause plant injury which, in turn, results in reduction of yield. In this study, the climatic crop productivity model YIELD has been applied to calculate rice productivity for the boro rice growing season (December/January-May) in Bangladesh under changing climatic conditions. The model estimates climatic influences on various rice plant-growth parameters. YIELD was tuned and validated to Bangladesh's environment to represent appropriate agroecological conditions. The model was run using long-term average climate data of 12 meteorological stations located in the major rice-growing regions in Bangladesh to establish baseline estimates of yield. For the climate change study, 20 scenarios were created by synthetically fluctuating thermal and solar climates in Bangladesh. Study results show that per 1° C increase in growing season mean air temperature, boro rice yield was reduced by 4.6%. It was also found that each 10% increase in incident solar radiation resulted in a 6.5% increase of boro rice yield in Bangladesh.  相似文献   

3.
In this study, information is collected on the weather, soils, field management and agricultural statistics in the Bangladesh, India and Myanmar(BIM) region. Crop growth parameters within the EPIC(Environmental Policy Integrated Climate) model are calibrated using cultivar data and regional experimental records of indica hybrid rice Fyou498 and Fengliangyou4 in China. Potential yields of rice are then simulated in the BIM region from 1996 to 2005. The effects of local irrigation and fertilization levels on super hybrid rice yield are examined. The potential yields of Chinese hybrid rice at local irrigation and fertilization levels in 2000 and at full irrigation and rational fertilization levels are found to be 10.22 t/ha and 11.33 t/ha, respectively. The potential for increasing monsoon rice production in the study region is 227.71 million tons. The eastern Indo-Gangetic Plain in India, the southeast coast of India Peninsula and the Ayeyarwady Delta in Myanmar have the largest potentials for monsoon rice production. The northeastern and southwestern areas of the Deccan Plateau and the northwestern region of the Indo-Gangetic Plain need to improve irrigation equipment to meet the water-use requirements of high-yield rice. The central and southern plains in Myanmar and northeastern India need greater access to nitrogen fertilization for high-yield rice.  相似文献   

4.
In this study, information is collected on the weather, soils, field management and agricultural statistics in the Bangladesh, India and Myanmar (BIM) region. Crop growth parameters within the EPIC (Environmental Policy Integrated Climate) model are calibrated using cultivar data and regional experimental records of indica hybrid rice Fyou498 and Fengliangyou4 in China. Potential yields of rice are then simulated in the BIM region from 1996 to 2005. The effects of local irrigation and fertilization levels on super hybrid rice yield are examined. The potential yields of Chinese hybrid rice at local irrigation and fertilization levels in 2000 and at full irrigation and rational fertilization levels are found to be 10.22 t/ha and 11.33 t/ha, respectively. The potential for increasing monsoon rice production in the study region is 227.71 million tons. The eastern Indo-Gangetic Plain in India, the southeast coast of India Peninsula and the Ayeyarwady Delta in Myanmar have the largest potentials for monsoon rice production. The northeastern and southwestern areas of the Deccan Plateau and the northwestern region of the Indo-Gangetic Plain need to improve irrigation equipment to meet the water-use requirements of high-yield rice. The central and southern plains in Myanmar and northeastern India need greater access to nitrogen fertilization for high-yield rice.  相似文献   

5.
The paper measures the level of crop diversity and identifies factors influencing diversification using a panel data of 17 regions of Bangladesh covering a 19 year period (1990–2008). Results revealed the trends that agricultural areas allocated to high‐yielding variety rice, spices and vegetables has increased, while areas cultivating traditional rice, minor cereals, oilseeds, pulses, jute and sugarcane has declined at variable rates across regions with significant differences. The level of crop diversity is also significantly different across regions and has decreased in 2008 from its 1990 level in most regions except Faridpur, Khulna and Sylhet. Among the determinants, an increase in the relative prices of vegetables and urea fertilizer, extension expenditure, labour stock per farm, average farm size, irrigation and a reduction in livestock per farm significantly increase crop diversity. Price policies to improve vegetable prices and investment in irrigation infrastructure and extension services are suggested to promote crop diversity in Bangladesh.  相似文献   

6.
水稻是孟加拉国、印度和缅甸最重要的粮食作物,研究中国超级杂交稻对孟印缅地区的水稻增产潜力,对于保障孟中印缅经济走廊的粮食安全与区域可持续发展具有重要的现实意义。在全面收集孟印缅地区气候、土壤、田间管理信息和农业统计数据的基础上,结合中国籼型杂交稻F优498和丰两优4号的品种信息和区试数据,通过EPIC模型模拟了1996-2005年雨季孟印缅3国在不同情景下的超级稻生产潜力,并分析了孟印缅地区主要胁迫因子对超级稻单产潜力的影响。研究表明:① 中国超级杂交稻在孟印缅地区2000年的灌溉和施肥水平下单产潜力为10.22 t/ha,在充分灌溉且合理施肥的水平下单产潜力为11.33 t/ha。② 孟印缅地区雨季稻的增产空间达22771万t,水稻增产潜力最大的地区是印度的恒河平原东部、印度半岛东南沿海与缅甸的伊洛瓦底三角洲。③ 印度德干高原东北部、西南部和印度大平原西北部需要进一步完善灌溉设备以满足高产水稻用水,缅甸的中南部平原地区和印度的东北地区则需要增施氮肥以满足高产水稻用肥。  相似文献   

7.
This paper provides a detailed analysis of agricultural land use change in Bangladesh over a 59‐year period (1948–2006) and examines how these have impacted crop diversity, productivity, food availability and the environment. The key findings of the analysis are: first, land use intensity has increased significantly over this period, mainly from the widespread adoption of a rice‐based Green Revolution technology package beginning in the early 1960s; second, contrary to expectation, crop diversity too has increased; third, although land productivity has increased significantly, declines in the productivity of fertilizers and pesticides raise doubts over sustaining agricultural growth; fourth, food availability has improved, with a reversal in the dietary energy imbalance in recent years despite a high population growth rate; and finally, the production environment has suffered with widespread soil nutrient depletion experienced in many agroecological regions. The policy implication points towards crop diversification as a desired strategy for agricultural growth to improve resource economy, productivity and efficiency in farming in Bangladesh.  相似文献   

8.
Four dates of Landsat Thematic Mapper data from 1993, April 9, July 30, August 15, and September 16, were used to assess temporal and spatial patterns of lake area and dimensions of suspended sediment concentration in Tuttle Creek Reservoir, Kansas. In 1993, excessive precipitation in the Big Blue River Basin, and throughout much of the Upper Middle West, led to widespread flooding. Rains produced substantial erosion, sediment movement down the stream network, and a runoff volume that filled Tuttle Creek Reservoir, a U.S. Army Corps of Engineers flood control structure. The April 9 data are from before the flood, the July 30 data are from the time of maximum pool size and use of the emergency spillway, and the August and September data document the declining pool sizes. Three separate analyses were performed on each of the four dates of Thematic Mapper data. One set of analyses involved applying an existing physical model that uses at-satellite reflectance for TM Band 3 to estimate variations in suspended sediment, turbidity, and Secchi depth throughout the reservoir. Maps of estimated parameters of water quality for the four individual dates were compared and analyzed to document spatial and temporal changes. The second research method involved unsupervised classification (ERDAS ISODATA algorithm) of the data from the Tuttle Creek Reservoir. Water areas were grouped into coherent classes for further spatial analysis using a two-step or layered classification procedure for each date. The third analysis used a GIS overlay technique to compare the area of the water surface for each of the four dates with the flood pool as marked on U.S.G.S. 7-1/2 minute quadrangles. Comparisons document the major change in lake area between April and July, the high levels of suspended sediment in mid-summer, and the decline in pool size and concentrations of suspended sediment by mid-September. The study illustrates the advantages of using remote sensing to assist in documenting a relatively short-term environmental hazard. This study also demonstrates the value of Landsat Thematic Mapper data for use in mapping geographic variations in water area and quality in conjunction with a major flood event.  相似文献   

9.
This article addresses the need to better understand the complex interactions between climate, human activities, vegetation responses, and surface ozone so that more informed air‐quality policy recommendations can be made. The impacts of intraseasonal climate variations on ozone levels in Tucson, Arizona from April through September of 1995 to 1998 are determined by relating variations in ozone levels to variations in atmospheric conditions and emissions of ozone's precursor chemicals, volatile organic compounds (VOCs) and nitrogen oxides (NOx), and by determining month‐specific atmospheric conditions that are conducive to elevated ozone levels. Results show that the transport of ozone and its precursor chemicals within the Tucson area causes the highest ozone levels to be measured at a downwind monitor. The highest ozone levels occur in August, due in part to the presence of the North American monsoon. Atmospheric conditions conducive to elevated ozone concentrations differ substantially between the arid foresummer (May and June) and the core monsoon months ( July and August). Transport of pollution from Phoenix may have a substantial impact on elevated ozone concentrations during April, May, and June, while El Paso/Ciudad Juarez –derived pollution may contribute significantly to elevated ozone concentrations in August and September. Two broad policy implications derive from this work. Regional pollutant transport, both within the U.S. and between the U.S. and Mexico, is a potential issue that needs to be examined more intensively in future studies. In addition, spatiotemporal variations in sensitivities of ozone production require the adoption of both NOx and VOC control measures to reduce ozone levels in the Tucson area.  相似文献   

10.
In this study, the Land Use Dynamic Simulator model was applied to investigate the impact of farm credit as an adaptation strategy to cope with effects of climate variability on agricultural land‐use change and crop production in the Vea watershed in Ghana. The authors identified the determinants of crop choices within the landscape (e.g., farm household and biophysical characteristics of farm plot). The crop choice sub‐model was then linked to the crop yield sub‐model to determine the yields of selected crops. In adapting to the impacts of climate variability, the maize credit adoption sub‐model under the maize cultivation credit scenario was integrated into decision‐making. This was simulated for a 20‐year period, and compared with the business‐as‐usual scenario. Under the simulated maize credit scenario, maize adopters increased from about 20 per cent to about 50 per cent and the area allocated for maize cultivation significantly increased by about 266 per cent. Consequently, the average annual aggregated household crop yield increased by 6.3 per cent higher than in the business‐as‐usual scenario. This simulation study shows that access to maize credit can significantly influence agricultural land‐use change and food availability in the study area. However, although access to farm credit may translate into food availability, the sustainability of this strategy is questionable.  相似文献   

11.
近20年气候变暖对黑龙江省水稻增产的贡献   总被引:35,自引:1,他引:34  
方修琦  王媛  徐锬  云雅如 《地理学报》2004,59(6):820-828
研究过去的气候变暖对作物产量的影响是认识变暖对农业影响的有效途径,但如何定量区分出气候变化和技术发展对粮食作物的影响程度是目前研究的难点。本文提出的算法在一定程度上可以克服传统算法缺陷,用此方法估算过去20年气候变暖对黑龙江省水稻单产增加的贡献率,结果表明:20世纪80年代相对于70年代水稻单产增加了30.6%,其中由气候变暖带来的增产量占实际增产量的12.8%~16.1%,相当于使70年代的单产增加3.9%~4.9%。20世纪90年代水稻单产较80年代增产42.7%,其中,气候变暖对单产增加的贡献率约为23.2%~28.8%,相当于在20世纪80年代的单产水平上增产9.9%~12.3%。  相似文献   

12.
ARIMA time series model building techniques are used to construct fifty-one state gasoline demand models based on monthly data for the period of January, 1975 to July, 1960. Statistically satisfactory models are obtained for all states. Price elasticity estimates are >0 for all states. All but four are statistically significant at the 0.05 level. The significant price elasticity estimates range from ?0.138 to ?0.377, with most clustering about ?0.2. Estimates of state gasoline supply shortages for May, June, and July, 1979 are also presented which range from 0 to 8 percent of normal consumption for the three-month-period.  相似文献   

13.
黑龙江省冷害对水稻产量的影响   总被引:11,自引:3,他引:8  
以黑龙江省为例, 比较了在大尺度范围内、利用传统的站点平均法以及基于格点水稻密度分布的泰森多边形面积权重法所得的两种省级水稻气象数据差异, 并分析了1960-2009 年内, 不同时间尺度上温度和降水的变化趋势特点。针对当地水稻低温冷害频发及其危害严重的实际情况, 对比研究了气象行业标准(QX/T 101-2009) 和国家标准中有关低温冷害的指标定义, 以及国际上较通用的有效负积温算法(GDDn-) 这三种指标在反映黑龙江省水稻冷害事件上的能力, 结果表明:气象行业标准可以较好地反映延期型冷害对水稻的影响, 而GDD指标在反映障碍型冷害上均优于气象行业及国家标准。利用时间序列模型对包含延迟型和障碍型两种冷害影响的黑龙江省水稻产量进行拟合, 回归方程的解释能力可达92% (p < 0.05)。本研究定量得出了人为因素和气象因素对黑龙江省水稻生产的影响分别占87.2%和12.8%的结论, 并检测出近年来水稻抽穗开花期障碍型冷害的波动增加趋势, 为明确今后低温冷害的防御重点提供科学参考。  相似文献   

14.
The starting dates of the pre-summer rainy season during historical times (1736- 1911) in Fuzhou and Guangzhou of South China, were determined and reconstructed on the basis of historical documents in the Yu-Xue-Fen-Cun archive, together with observed features of precipitation during the pre-summer rainy season. In addition, starting dates of the pre-summer rainy season from 1953 in Fuzhou and from 1952 in Guangzhou were reconstructed for the instrumental period. These data allowed for analyses of inter-annual and inter-decadal changes in the starting dates of the pre-summer rainy season in South China over the past 300 years. Results show that the mean starting date of the pre-summer rainy season in South China was the first pentad of May; in addition, periodicities in the starting dates of 2-3 years, 10 years, and 40 years were detected during the period 1736-1911, and of 2-3 years, 10 years, and 22 years during the instrumental period. From 1736 to 1911, the earliest starting dates at Fuzhou and Guangzhou both occurred at the fourth pentad of April, while the latest starting dates were at the sixth pentad of May in Fuzhou and the first pentad of June in Guangzhou. During the instrumental period, the earliest and latest starting dates were at the fourth pentad of April and the first pentad of June, respectively, in both Fuzhou during 1953-2010 and Guangzhou during 1952-2010. The maximum difference between neighboring decades during 1736-1911 was 2.2 and 1.6 pentads in Fuzhou and Guangzhou, respectively, and during the instrumental period it was 2.5 and 2.4 pentads in Fuzhou and Guangzhou, respectively.  相似文献   

15.
ThespatialdistriblltionofcropcultivatedinChina,especiallyofcroptyPes,vanetiesandcroppingsystems,lspnnclpallydeterm1nedbyclimaticcondltions,andarelatlvestableconcentratedroponaldistributionpattemhasbeenformedinrecat4Oyears.Temporally,cropWeldshowsanincrementaltrendandanoscillationpattenlonlargeandmesialtimescalesbecauseoftheianuenceofagnculturaltechnologyandsoclalfaCtors,respeCtively.ThesharPvariationofaghculturalproduCtsinquantityandqualityfromyeartoyearispnnc1pallycausedbyclimate.This,onth…  相似文献   

16.
甘肃省夏季异常高温及其环流特征分析   总被引:5,自引:0,他引:5  
赵庆云  赵红岩  王勇 《中国沙漠》2007,27(4):639-643
利用甘肃省62个气象观测站1960—2003年6—8月逐日最高气温、高度场和温度场格点资料,分析了高温极值、高温范围、高温持续时间的变化,并对历史上出现的四次极端高温天气过程的环流形势特征进行了分析。结果表明:甘肃河西地区极端最高气温各月之间的差异大,6月极端值最小,7月极端值最大,7月极端最高气温线性变化略呈上升趋势,6月、8月线性变化呈下降趋势,20世纪90年代极端最高气温增温不明显。河东地区极端最高气温各月之间的差异小,7月、8月的变化呈上升趋势,1995—2002年的增温明显。6月全省最大范围的高温天气出现在60年代;7月,90年代后期出现大范围高温天气的年份明显比以前增多。7月持续高温时间在90年代明显增长。100 hPa南亚高压,300 hPa暖中心、500 hPa副热带高压闭合单体控制西北地区上空,对流层上下层暖高压中心相对应,中心位置基本一致时,将出现大范围、持续性的异常高温天气。  相似文献   

17.
近46年来中国东部季风区夏季气温变化特征分析   总被引:5,自引:1,他引:4  
利用中国东部季风区375个测站夏季平均气温资料,分析季风区夏季气温的变化特征.结果表明:(1)近46 a东部季风区夏季气温年平均呈缓慢上升趋势,但淮河流域出现下降趋势;(2)夏季气温稳定性随纬度增加而减小;(3)季风区夏季气温年均增温率0.104℃/10 a,全区平均状况看,1970年代中期后开始表现明显上升趋势;(4)季风区夏季气温变化首先表现为全区一致的变化型,然后为南北反相变化型;(5)根据REOF分析将季风区夏季气温异常分6个气候空间类型,东北、华北、江南及华南均呈现上升增温趋势,西南地区增温缓慢,淮河流域则呈现与全球变暖不一致的降温趋势.  相似文献   

18.
The starting dates of the pre-summer rainy season during historical times (1736-1911) in Fuzhou and Guangzhou of South China, were determined and reconstructed on the basis of historical documents in the Yu-Xue-Fen-Cun archive, together with observed features of precipitation during the pre-summer rainy season. In addition, starting dates of the pre-summer rainy season from 1953 in Fuzhou and from 1952 in Guangzhou were reconstructed for the instrumental period. These data allowed for analyses of inter-annual and inter-decadal changes in the starting dates of the pre-summer rainy season in South China over the past 300 years. Results show that the mean starting date of the pre-summer rainy season in South China was the first pentad of May; in addition, periodicities in the starting dates of 2-3 years, 10 years, and 40 years were detected during the period 1736-1911, and of 2-3 years, 10 years, and 22 years during the instrumental period. From 1736 to 1911, the earliest starting dates at Fuzhou and Guangzhou both occurred at the fourth pentad of April, while the latest starting dates were at the sixth pentad of May in Fuzhou and the first pentad of June in Guangzhou. During the instrumental period, the earliest and latest starting dates were at the fourth pentad of April and the first pentad of June, respectively, in both Fuzhou during 1953-2010 and Guangzhou during 1952-2010. The maximum difference between neighboring decades during 1736-1911 was 2.2 and 1.6 pentads in Fuzhou and Guangzhou, respectively, and during the instrumental period it was 2.5 and 2.4 pentads in Fuzhou and Guangzhou, respectively.  相似文献   

19.
ABSTRACT. Pressured by structural adjustment loan conditions, Côte d'Ivoire reduced state support for rice production and processing during the 1990s. In this article we examine how various actors in the rice commodity chain adapted to the macroeconomic reforms. Following a brief history of the rice sector, we present the results of fieldwork based on interviews conducted in 2002 of farmers, millers, traders, and workers in the state extension service and nongovernmental organizations. We found that, in the absence of state supports for farmers, private millers became the focal point of regional producer‐processor rice networks. The four networks identified became the sole source of domestic commercial rice when the state removed subsidies for fertilizer and modern seeds, privatized extension, and liberalized prices and imports. To increase their role in the national rice supply, the rice networks may need support through microlending and a focus on niche markets.  相似文献   

20.
近30年辽宁省夏季人体舒适度区域特征分析   总被引:5,自引:0,他引:5  
曹永强  高璐  王学凤 《地理科学》2016,36(8):1205-1211
基于辽宁省25个气象测站1984~2013年6~8月的逐日平均气温、平均风速、相对湿度以及日照时数等数据,以温湿指数、风效指数及着衣指数综合加权法与旋转经验正交函数分解法(REOF)相结合,分析辽宁省夏季舒适程度,并对舒适度变化趋势进行舒适区域划分。结果表明:温湿指数、风效指数及着衣指数均呈现出6月指数最低,7月指数相对较高的特点,年际变化特征不明显,且3个指数各个月空间分布上呈现的趋势并不相同。 6月全省均处于“舒适”等级,而7月和8月处于“比较舒适”等级,说明6月是辽宁省夏季旅游最佳月份。6月和7月在空间分布中呈现出由西北向东南递增的趋势,但8月却呈现出相反的趋势。 根据旋转经验正交函数分解方法对前3个载荷向量旋转后的结果,将辽宁省划分为3个舒适区域,分别为辽宁中部及西北部区域、辽宁东部区域和辽东半岛区域。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号