西北干旱灾害及其气候趋势研究

利用西北五省1950～2000年降水、温度和农作物旱灾面积资料,用降水的Z指标法,农作物受旱成灾率确定了西北干旱指标和旱灾等级,分析了西北旱灾特征及气候变化趋势。表明西北农业旱灾以70、90年代最严重,而且呈增加趋势,气温在升高,降水在减少。根据预测21世纪前十年西北干旱有所减轻。     

安徽省农业旱灾规律及其对粮食安全的影响

利用1949年以来59 a农业自然灾害和粮食生产数据,分析安徽省农业旱灾变化规律和粮食安全态势,探讨农业旱灾对粮食安全的影响.结果表明:农业干旱灾害呈现明显周期性波动,干旱轻重灾情交替出现,其波动周期大致为5～10 a.近30 a来干旱灾害对该省粮食生产的致灾强度越来越大,即其危害日趋严重.粮食总产量、粮食单产和粮食播种面积的年变化率均与干旱受灾率、成灾率、灾害强度指数、受灾率异常指数和成灾率异常指数等指标显著负相关.其中以灾害强度指数、受灾率异常指数和成灾率异常指数对粮食生产的影响更为显著,且受灾率异常指数的影响最为显著.该研究结果可为安徽省农业防灾减灾体系建设和粮食安全提供参考和借鉴.     

塔里木河流域旱灾发生规律

通过1949-2010年塔里木河流域干旱灾害资料,研究了塔里木河流域干旱灾害的频次和旱情,采用波谱分析方法进行了周期分析。结果表明：1949-2010年,塔里木河流域有记载的干旱灾害共59次,平均每1.04 a发生1次。在59次的灾害中,特大旱灾、重大旱灾、中度旱灾、轻度旱灾分别为10次、25次、11次、13次,分别占16.96%、42.37%、18.64 %和22.04%,3级以上大旱灾共发生35次,平均每1.75 a发生1次,占干旱灾害发生年总数的59.32%。塔里木河流域1990-2010年受旱率超过20% 的有14 a,受旱率和成灾率最高的年份为1993年,分别为37.5%和17.3%。受旱率超过 25%、成灾率超过15%的有3 a,分别是1993、2001年和2002年,平均7 a一遇;每5 a不同级别平均受旱面积依次为2.65×10⁵、2.22×10⁵、3.23×10⁵ hm²和3.53×10⁵ hm²; 平均成灾面积分别为1.22×10⁵、1.05×10⁵、1.78×10⁵hm²和2.31×10⁵hm²。塔里木河流域在1950-2010年存在准2 a、准3 a、准6 a、准13 a的周期,且准2 a、准3 a的周期相当显著,置信度分别达99%和95%。     

旱灾的概率分布规律及其成果应用初探

依照旱作物旱灾估测方法，对几个代表站有旱灾的年份，逐年进行旱灾计算，经系列分析，以受旱作物欠收幅度表示的旱灾概率为均匀分布。通过回归式确定有关参数后，应用这一理论对吉林省西部干旱地区进行了旱灾测算、干旱经济分区、灌溉定额设计等。     

陕西省54a来农业干旱灾害特征研究

干旱灾害是影响陕西省农业经济可持续发展的主要限制因素。本文利用陕西省54a来的农业旱灾灾情资料对旱灾特征进行了详细分析和预测,得出陕西省旱灾有发生频率加快、灾情加重趋势,干旱灾害具有较强的持续性。干旱受灾面积有3~4a的变化周期,农业旱灾成灾率和受灾率呈正相关,线性回归方程为y=0.32+0.73x。灾害有明显的区域差异性,陕北灾情最严重,关中次之,陕南最轻。灾害主要集中在渭南市、榆林市、商洛市、咸阳市、汉中市、延安市、铜川市、宝鸡市、洛川县、定边县。     

基于可变模糊评价法的农业旱灾灾后恢复力评估研究——以河北省为例

在综合考虑河北自然条件、社会经济条件,并借鉴已有干旱灾害恢复力研究成果的基础上,依据数据的可取性和详尽程度,选取降水量、复种指数、单位面积粮食产量、人均粮食产量、有效灌溉率、劳动力比重、农民人均收入和农业产投比等八个指标,构建农业旱灾灾后恢复力评价指标体系。通过层次分析法确定各指标的权重,构建可变模糊评价模型,对河北省11个市干旱灾害灾后恢复力进行评估。结果表明,石家庄旱灾灾后恢复力最高,级别特征值为4．2329,其次是唐山市为4．0046,张家口市恢复力最低,级别特征值为1．8079,各地区旱灾灾后恢复力差异明显。而在影响恢复力高低的因素中,发现不同的因素对旱灾灾后恢复力的影响程度是不同的。降水量是影响农业干旱灾害灾后恢复力的最主要自然因素,有效灌溉率在农业干旱灾害灾后恢复力评价指标体系中占较大的权重,对灾后恢复力的影响较大,农民人均收入和人均粮食产量对灾后的救助及农民生活的恢复重建也具有较重要的调节作用。     

宁夏干旱及其对农业生产的影响

以1951年1月－2000年5月全区19个气象台站的逐月降水资料为基础,采用降水量距平百分离和旱灾指数作为干旱灾害的指标,建立了寄存地区各种干旱类型的旱灾序列,并进行统计分析,较确切地反映出该区域内各年干旱轻重的程度,综合研究了干旱对农业生产的影响。结果表明,宁夏主要以春旱为主,春夏连旱最多,对宁夏影响最大的是秋春夏连旱;近年来干旱与非干旱的程度、范围差距进一步加大,出现干旱极值情况比以前增多,受旱面积有逐年增加的趋势;气候正在向干旱化发展。根据实际情况提出了抗旱对策。     

干旱气候变化对甘肃省干旱灾害的影响及防旱减灾技术的研究

西北地区干旱气候变化的主要特征,表现在20世纪90年代夏季降水量有明显减少趋势,干旱化趋势主要发生在西北地区东部,干旱连年发生,尤其是甘肃省河东地区.干旱气候的产生带来了严重的干旱灾害,甘肃省90年代的干旱发生最为频繁,干旱灾情最为严重,1995年是干旱最严重的一年,成灾率达45%,其次是2000年,成灾率为35%,伏秋旱连春末初夏旱是造成夏粮严重减产的旱灾类型.干旱气候变化引发干旱化趋势非常明显,应采取综合的技术措施减轻干旱危害,要加强干旱气候与干旱灾害的监测预测和改善生态环境、优化农业结构、提高水资源利用率以及大力开发空中水资源等防御对策.     

塔里木河下游沙漠化对绿洲农业生产的影响

荒漠化是全世界所面临的重大的环境灾害之一。塔里木河下游的沙漠化已经对该区域的绿洲农业生产产生了巨大的危害。本文通过对塔里木河下游沙漠化状况和典型生产团场农业生产状况的调查研究发现 ,沙漠化对塔里木河下游农业生产的影响 ,主要表现为下游来水量逐年减少 ,弃耕地面积增加 ;沼泽土面积减少 ,肥沃土壤面积增加 ;风灾、旱灾面积增加 ,盐碱灾害面积相对减少。减轻沙漠化对绿洲农业危害的措施 ,包括加强管理 ,增加塔里木河的来水量 ;发展节水灌溉技术 ,减少水资源浪费 ;调整作物结构 ,提高水资源利用率 ;保护荒漠植被 ,维护生态 ,完善防护林体系。     

库车干旱灌区农作物生产潜力分析及开发利用

对库车干旱灌区主要农作物的生产潜力分析表明，光合产量是实际产量的５倍～８倍，灌溉产量是实际产量的３倍～５倍，限制生产潜力发挥的主要因素是干旱少雨和地力低下，在保证灌溉的前提下，改良土壤和提高管理水平等农业综合技术，可使目前农作物产量提高２倍～４．６倍。     

Localization of metabolic sites of action of herbicides

Time- and concentration-course studies were conducted to determine the effect of thirteen herbicides on photosynthesis, respiration, RNA synthesis, protein synthesis, and lipid synthesis using isolated single leaf cells. Each herbicide was from a different chemical class. Appropriate ¹⁴C-substrates and product purification procedures were used for each process prior to liquid scintillation counting. The most sensitive metabolic site of inhibition was photosynthesis for atrazine, bromacil, dichlobenil, monuron, and paraquat; RNA synthesis for dalapon and dinoseb; protein synthesis for chlorpropham; and lipid synthesis for CDAA, chloramben, 2,4-D, EPTC, and trifluralin. However, with several herbicides, one or more process was almost as sensitive as the one mentioned above. All herbicides inhibited more than one process, and the most sensitive site of inhibition may not be the same process that was inhibited the greatest at the maximum concentration and maximum exposure time used. Therefore, a concept of metabolic sites of action, rather than a primary site of action, appears to be more meaningful for herbicides.     

福寿螺配偶个体大小选择性初步观察

通过野外观察与实验研究,掌握了福寿螺的婚配体制及其配偶选择性规律。福寿螺与多数低等动物一样,其婚配属于乱交制,无固定配偶;雌螺对与其交配的雄螺个体大小没有选择性,而雄螺对雌螺的个体大小有选择性,倾向于与较大个的雌螺交配。     

青稞种子带菌检测及杀菌剂消毒处理效果

为了研究青稞种子外部和内部携带真菌情况,比较不同杀菌剂对青稞种子的带菌消毒效果和对幼苗生长的影响,为青稞种子播前包衣处理和种传真菌病害防控提供依据,采用离体平皿法对云南迪庆‘云青1号’、‘云青2号’和‘短白青稞’3个主栽品种进行带菌检测,并对种子进行拌种或浸种处理测定6种杀菌剂对种子消毒效果,分析杀菌剂对种子发芽和幼苗生长的影响。结果表明:供试青稞种子表面携带的优势菌群为青霉(Penicilliumspp.)、镰刀菌(Fusariumspp.);种子内部寄藏的真菌主要为镰刀菌、核腔菌(Pyrenophoraspp.)、附球菌(Epicoccumspp.)、丝核菌(Rhizoctoniaspp.)、链格孢(Alternariaspp.)和木霉(Trichoderma spp.)。青稞不同品种的种子表面及内部携带的真菌种类差异较大。致病性测定表明,镰刀菌对种子萌发和幼苗生长影响最大,后期出现幼苗坏死现象。45%咪鲜胺EW、75%百菌清WP、50%福美双WP对青稞种子携带真菌均有显著抑制作用和消毒效果,50%福美双WP消毒效果最优,达100%;45%咪鲜胺EW、75%百菌清WP、50%福美双WP处理对青稞种子发芽和幼苗生长均无显著影响。     

厚朴病虫害种类的初步调查

采用标准地法和线路调查法,对湖北恩施市新塘乡双河厚朴基地的厚朴病虫害进行了系统调查,记录主要虫害13种,其中叶部害虫9种,枝干害虫2种,根部害虫2种。厚朴主要病害5种。藤壶蚧、厚朴枝角叶蜂和厚朴新丽斑蚜为湖北省首次报道,小绿叶蝉为厚朴新寄主记录种。同时记录了藤壶蚧的天敌6种,其中寄生小蜂2种,瓢虫4种;厚朴新丽斑蚜的天敌昆虫8种。对藤壶蚧、厚朴枝角叶蜂和厚朴苗木根腐病等重要病虫害的发生规律进行了初步调查,同时提出了防治建议。     

Effects of timing and method of application of Penicillium oxalicum on efficacy and duration of control of Fusarium wilt of tomato

The effects of timing and method of application of Penicillium oxalicum on the control of fusarium wilt of tomato were investigated. Application of P. oxalicum to tomato seedlings in seedbeds reduced disease caused by Fusarium oxysporum f.sp. lycopersici in a growth chamber by 45–49% and in glasshouse experiments by 22–69%. Disease suppression was maintained for 60–100 days after inoculation with the pathogen in the glasshouse. No disease reduction was observed in tomato plants where P. oxalicum was applied to seeds. Treatment with P. oxalicum did not affect the population of F. oxysporum f.sp. lycopersici in the rhizosphere.     

Systems of designation of pathotypes of plant pathogens12

A variety of systems of designation has evolved to name pathotypes of plant pathogens. The systems were evaluated to determine those best suited for particular purposes. Virulence and avirulence/virulence formulae of pathotypes have advantage over the use of consecutive numbers or letters given in chronological order of pathotype discovery. As soon as pathotype information exceeds a certain level of complexity, mathematical codes are most advantageous, in particular two codes, octal notation and coded triplets. A more universal adoption of the most appropriate codes is recommended to ease communication and comparisons of results.     

Mode of action of etoxazole

The mode of action of the 2,4-diphenyl-1,3-oxazoline acaricide/insecticide etoxazole has been argued to be moulting inhibition, but experimental results supporting this hypothesis are lacking. This study investigated the effect of etoxazole on chitin biosynthesis in the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Etoxazole induced moulting defects in fall armyworm larvae similar, if not identical, to those caused by benzoylphenylureas, a well-known class of insecticidal chitin biosynthesis inhibitors. Furthermore, in contrast to untreated larvae, the chitin content in the integuments of larvae several days after treatment did not differ from that in freshly ecdysed individuals, thus suggesting strong chitin biosynthesis inhibition in vivo. A more detailed investigation of the inhibitory potential by incubating cultured integument pieces from larvae of S. frugiperda with [14C]N-acetyl-D-glucosamine, a radiolabelled chitin precursor, revealed I50 values of 2.95 and 0.071 microM for etoxazole and triflumuron respectively. The incorporation of radiolabel into potassium hydroxide-resistant material was inhibited by etoxazole in a dose-dependent manner. Based on these results, it is concluded that the acaricidal and insecticidal mode of action of etoxazole is chitin biosynthesis inhibition.     

Mode of action of meturine

The effect of meturine on the light processes of photosynthesis was studied.Meturine is a herbicide for weed control in potato and cotton crops. It is a N-phenyl—N-hydroxy—N′-methylurea.The experiments were carried out on isolated pea and spinach chloroplasts.When examining photosystem I, reduced DPIP was used as an electron donor, whereas methyl-viologen served as an electron acceptor. When examining photosystem II, DPIP represented the electron acceptor.The obtained experimental results have pointed to the absence of the effect of meturine upon the photoreaction I.Unlike N-phenyl—N′, N′-dimethylureas (CMU, DCMU) meturine has been a very weak inhibitor of photoreaction II.The authors explain the photoreaction II inhibition of chloroplasts from plants treated with herbicidal doses of meturine by conversion of N-phenyl—N-hydroxy—N′-methylurea into Hill reaction inhibitor(s). N-Phenyl—N′-methylurea can be one of such meturine metabolites.Meturine herbicidal action is accounted for by meturine transformation into Hill reaction inhibitor(s) in the plant tissues.     

甲基硫菌灵标样的制备

本文介绍了用进口甲基硫菌灵样品，采用溶剂萃取，高速离心，重结晶，高效液相色谱，红外光谱等分析方法进行系统分离与鉴定，得到其标样的方法。