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1.
鄂尔多斯高原,干旱多风,水源贫乏,生态环境脆弱,由于不合理的利用, 全区沙漠化及东部的水土流失,西部的草场退化都很严重。整治措施:牧林为 主,种草种树;综合治理沙漠与水土流失;合理利用草原;粮草轮作;解决群 众的能源,煤矿的开采要与草原的恢复相结合。 鄂尔多斯高原位于内蒙古自治区的西南部,宁夏平原之东,河套平原之南,东北至黄河,东与南至长城。在行政区划上基本属于伊克昭盟。  相似文献   

2.
<正> 宁夏引黄灌区是我国著名的河套灌区的一部分,已有两千多年灌溉农业的历史。宁夏引黄灌区位于宁夏回族自治区的北部,南起中卫县,北止石咀山,东邻鄂尔多斯高原,西倚贺兰山及腾格里沙漠,南北长200多公里,东西宽20—40公里,海拔高度1100-1200米。灌区年平均日照2800-3100小时,无霜期160天左右,4至9月农作物生长季节≥10℃的积温为3200—3400℃。但灌区气候干旱少雨,年降水量仅200毫米,  相似文献   

3.
利用陕西省气象观测站气温和降水资料、干旱灾害记述资料,根据年旱涝等级、降水距平百分率以及CI干旱指数的分布与变化,分析比较了冷期1965—1966年干旱和暖期1994—1995年干旱的范围、程度以及干旱过程演变的异同。结果表明,冷暖背景下均会出现连续的干旱,当暖期与降水减少相遇时,出现的干旱更为严重;处于干旱半干旱区的陕北,干旱过程往往持续时间较长,处于半湿润区和湿润区的关中、陕南,干旱时段内往往会出现多个干旱过程。陕北1994—1995年的干旱天数少于1965—1966年,而关中、陕南1994—1995年的干旱天数多于1965—1966年,同一干旱事件在各地会呈现出不同的特点。  相似文献   

4.
中国是世界上受干旱影响最严重的国家之一,干旱频发给我国经济社会发展和生态环境造成严重影响。为分析近40 a干旱事件的时空特征,本文结合三维聚类算法,从干旱事件时空联动的本质出发,识别中国1981—2020年间干旱事件并定量分析干旱事件的时空动态演变过程。主要结论如下:三维聚类算法能有效识别干旱事件及其动态变化过程。中国1981—2020年间发生持续2个月及以上的干旱事件102场,空间上,干旱事件空间轨迹倾向于自东向西发展;时间上,干旱事件时间重叠度较高,长历时干旱多具有多峰特点。此外,覆盖范围广且严重度高的干旱事件集中发生于2005—2010年。本文结论有助于发现中国干旱事件的时空演化规律,为我国干旱监测和干旱风险管理提供科学参考。  相似文献   

5.
利用大型移动防雨棚开展了玉米干旱胁迫及复水试验,通过分析玉米植株茎流速率变化规律,揭示了不同程度干旱胁迫及复水对玉米植株茎流速率的影响及其对环境因子的响应规律。结果表明:1不同发育期干旱胁迫及对照试验的玉米植株茎流速率在晴天均呈单峰曲线,在阴天或多云天呈现不规则的上下波动状态;干旱胁迫导致玉米茎流速率显著下降并且峰值提前;复水后的茎流速率与对照间的差异缩小,但仍低于对照且峰值提前;2比较拔节—吐丝期茎流速率平均值为:对照重度干旱胁迫中度干旱胁迫,吐丝—乳熟期和乳熟—成熟期均为:对照中度干旱胁迫重度干旱胁迫。3茎流速率与净辐射、气温呈现显著正相关,与相对湿度呈现显著负相关;重度干旱胁迫后,土壤水分的亏缺影响了玉米植株茎流速率,减弱了相对湿度对其茎流速率的影响。  相似文献   

6.
基于Copula函数的辽西地区农业气象干旱灾害分析   总被引：1，自引：0，他引：1  
干旱作为辽西地区频发的自然灾害之一,对农业影响显著。综合考虑气象干旱灾害的多要素作用,本文基于SPI指数利用游程理论提取辽西地区1956—2014年农业气象干旱的历时和强度,在确定单变量边缘分布的基础上采用Copula函数分析干旱发生的联合概率和重现期,并以1991—2011年农作物旱灾实况为依据,探讨气象干旱重现期与作物旱灾损失之间的联系。结果显示:(1)干旱历时和干旱强度分别符合Weibull和Gev分布,Frank-Copula适合模拟辽西地区的干旱联合分布;(2)本区发生历时和强度双低、短历时-高强度、长历时-低强度干旱的可能性较大;(3)高强度-短历时和低强度-长历时组合下重现期多为2—4个月,辽西多轻、中旱;(4)1991—2011年旱灾实际重现期与理论重现期接近,表明联合重现期能更好地体现灾害发生频次;(5)重现期低于2个月为轻度干旱,2—8个月为中度干旱,高于8个月为重度干旱,农业部门可根据联合重现期预测出的干旱等级采取有针对性的防旱抗旱措施。  相似文献   

7.
青藏高原季风变化及其与鄂尔多斯高原夏季降水的关联   总被引：2，自引：1，他引：1  
选用1958～2002年逐月600hPa2.5°×2.5°ECMWF再分析资料和1961～2000年鄂尔多斯高原夏季降水资料,计算了高原季风指数,分析了高原季风指数的年代际变化及其与鄂尔多斯高原夏季降水的关联.结果表明:近40年来,高原季风总体呈冬季风减弱、夏季风增强的趋势;高原季风的变化与鄂尔多斯高原夏季降水的多少密...  相似文献   

8.
山西南部季节性干旱特征及综合防御技术   总被引：1，自引：0，他引：1  
采用标准化降水指数(SPI)为干旱指标,计算了山西省运城市49年(1958—2007年)各月干旱指数,并在此基础上分析了山西南部地区季节性干旱特征。研究表明,干旱强度与干旱频率在不同年代际表现特征不同。与运城地区49年同期均值相比,进入20世纪90年代后,春旱发生频率、干旱强度分别提高了29.0%、5.1%;夏旱发生频率提高41.9%,干旱强度下降了7.4%;秋旱发生频率下降了23.8%,干旱强度提高了7.7%;冬旱发生频率下降了26.6%,干旱强度下降了37.5%。干旱的季节性特征为春旱和夏旱有加重趋势,秋旱和冬旱有减弱趋势。春旱(3—5月)和伏旱(7—8月)作为可预见性干旱,可采用土壤墒情监测、干旱预警、制定系统性抗旱措施等综合防御技术。对于不可预见类型干旱,可采用建立抗旱水源、储备抗旱机械等策略。  相似文献   

9.
利用山西省50个气象站1972—2012年春季和夏季降水量资料,基于标准化降水指数SPI,从山西省整体干旱趋势、干旱面积变化趋势、干旱强度变化趋势、干旱持续时间特征和干旱空间变化等方面,研究了山西省近40年的春季夏季干旱特征,同时结合玉米产量资料,揭示了SPI指数表征干旱特征的优势。结果表明,春季SPI呈增大趋势,气候倾向率为0.15·10a-1,有湿润的倾向,干旱强度和干旱面积均呈下降趋势,1972—1981年山西省春季平均干旱面积为42%,而近10年为26%,表明山西省春季干旱程度有减轻趋向,但区域性或持续性极端干旱事件频发,因此,春季的干旱并未得到有效缓解。夏季SPI呈减少趋势,气候倾向率为-0.14·10a-1,有干旱的倾向,但干旱强度呈下降趋势,气候倾向率为-0.055·10a-1;1972—1981年夏季平均干旱面积为11%,而近10年上升到14%,但较少出现区域性或持续性干旱事件。夏季干旱特别是中等以上强度的干旱显著影响玉米产量,而春季干旱对产量影响较小。SPI值与玉米产量的相关系数要高于降水量,表明基于标准化降水指标的干旱分析在农业生产方面更具指导意义。  相似文献   

10.
<正> 由于干旱地区,尤其半干旱区的压力越来越大,改进再生资源的利用,区域气候分析,特别是暖季降水的情报,必然对更好地利用土地做出重要的贡献。奇瓦瓦沙漠不多的降水是山地屏障,亚热带高压和大陆性共同作用的结果。几乎完全干旱的地区与最近的可降水源也——墨西哥湾和热带东太平洋的距离是400—700km,干旱的原因,地形屏障作  相似文献   

11.
四种甘草的抗蚜性研究   总被引：1，自引：0，他引：1       下载免费PDF全文
李新成 《植物保护学报》1993,20(3):210-210,216
甘草是一种重要的资源植物,近年来在新疆、甘肃、宁夏、内蒙古、黑龙江等地的栽培生产中,蚜虫为害突出。为此作者在伊盟甘草基地对不同产地、不同种甘草的抗蚜性作了观察,以寻找较好的抗源材料。  相似文献   

12.
甘草单胞锈菌的孢子阶段、生活史及防治研究   总被引：3，自引：0，他引：3  
甘草单胞锈病是新疆南北地区甘草栽培中一种毁灭性病害。1987—1989年在田间和室内对甘草单胞锈菌〔Uromyces glycyrrhizae(Rabenh.)Magn.〕的孢子阶段、生活史和防治进行了研究。结果表明,本菌为单主全孢型锈菌,能在甘草生长期产生5种不同的孢子。人工接种证实本菌的夏、冬(担)孢子能于冬前发芽侵染甘草根蘖芽,潜伏越冬,于次春出现夏孢子型、性(锈)子器型和混生型3种不同的系统侵染病株,成为当年发病的初侵染源。夏孢子于生长季节重复侵染叶部、茎梢和根蘖芽、腋芽,产生局部和系统侵染,造成毁灭性为害。  相似文献   

13.
<正> Licorice (Glycyrrhira) is one of the important medical resources in arid area. It is dis-tributed between 30 and 55 degrees north latitude, especially in arid area 40 degrees northlatitude. There are about nine or ten species of licorice in our country. Not only it has ahigh economical value, but also it is an important sand-control plant for protecting  相似文献   

14.
论干旱地区甘草资源的保护与利用   总被引：4，自引：0，他引：4  
<正> 甘草以其特有的深根耐旱的生物学特性分布于我国北纬40°左右的干旱半干旱地区,主要集中分布在新疆、甘肃、宁夏、内蒙等半干旱草原与荒漠地区,自古以来,甘草“根茎入药、性平、味甘能和百药”,是重要的中药药材。如今,甘草的根、茎、叶、种子分别广泛应用于医药、食品、轻工、冶金、畜牧各业。对农业来说,它既是珍贵的野生中药植物资源,又是羊只过冬的优质饲草资源,具有一定改善土地沙化的作用,在草原生态  相似文献   

15.
Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.  相似文献   

16.
Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.  相似文献   

17.
The genera ofMicrogaster Latreille 1804 andHygroplitis Thomson 1895 from China are presented systematically in this paper. Thirty-two species ofMicrogaster and three species ofHygroplitis are known in China. Diagnosis, character variation, distribution and host of each species among the two genera are presented, including its host and distribution. Keys to the species ofMicrogaster andHygroplitis are given. http://www.phytoparasitica.org posting Dec. 19, 2006.  相似文献   

18.
Plant Viruses Transmitted by Whiteflies   总被引：18，自引：0，他引：18  
One-hundred and fourteen virus species are transmitted by whiteflies (family Aleyrodidae). Bemisia tabaci transmits 111 of these species while Trialeurodes vaporariorum and T. abutilonia transmit three species each. B. tabaci and T. vaporariorum are present in the European–Mediterranean region, though the former is restricted in its distribution. Of the whitefly-transmitted virus species, 90% belong to the Begomovirus genus, 6% to the Crinivirus genus and the remaining 4% are in the Closterovirus, Ipomovirus or Carlavirus genera. Other named, whitefly-transmitted viruses that have not yet been ranked as species are also documented. The names, abbreviations and synonyms of the whitefly-transmitted viruses are presented in tabulated form together with details of their whitefly vectors, natural hosts and distribution. Entries are also annotated with references. Whitefly-transmitted viruses affecting plants in the European–Mediterranean region have been highlighted in the text.  相似文献   

19.
Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.  相似文献   

20.
A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVYN strain and six to the PVYO strain. No PVYC was found. Two other isolates reacted serologically like PVYO, but were unable to elicit a hypersensitive response from the Nytbr gene and probably represent the PVYZ group. At the molecular level, these two isolates showed a combination of both PVYO and PVYN and could be recombinants of these strains. Another isolate reacted serologically like PVYO, but induced vein necrosis in tobacco, like PVYN-Wilga. Some PVYN isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVYNTN group. The PVYNTN, PVYN-Wilga and PVYZ groups probably represent pathotypes within strains PVYN and PVYO, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.  相似文献   

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