甘肃省参考作物蒸散量及影响因素的时空分异特征

为了探寻甘肃省参考作物蒸散量(ET0)的变化特征及其影响因子,利用甘肃省29个气象测站1951—2013年的观测资料,采用FAO-Penman-Monteith(98)公式计算甘肃省不同区域的ET0,并依靠线性趋势方程、云模型、通径分析和指标敏感性分析方法对ET0时空分异特征和影响因子进行分析。结果表明:甘肃省ET0以2.11mm·10a-1的倾向率呈现出增长趋势,除河西地区以0.71 mm·10a-1的倾向率呈递减趋势外,其余三个地区均呈增长状态。ET0空间分布总体上呈现为西北地区大于东南地区,河西地区最为离散、不稳定,陇东地区最为均匀、稳定。ET0的主要影响因子具有空间变异性,河西和陇南地区为平均温度,陇中和陇东地区为平均相对湿度和日照时数。但是ET0的变化是多因素共同影响的结果,平均风速是河西地区和陇东地区的另一主要影响因素,陇中地区为平均相对湿度,陇南为日照时数。     

甘肃省近58年春旱的气候特征及其对农业的影响

利用甘肃省80个气象观测站1951~2008年的春季(3~4月)历年降水量距平百分率确定干旱标准,统计分析历年春旱发生的频率和范围。结果表明:甘肃省春旱发生频率比较高,其频率范围为30%~50%,河西走廊为40%~50%,陇中北部和陇东为40%左右,陇中南部、陇南和甘南高原为30%左右。全省春旱频率呈增加趋势,河西、陇东和陇南呈增加趋势,陇中趋势平稳,2000~2008年全省及各地春旱次数都在迅速增加。在近58年中,全省春旱范围的历年变化呈逐渐扩大趋势,陇东和陇南与全省相同,河西和陇中呈逐渐缩小趋势。     

甘肃不同类型农区农业自然环境资源特点及农田生产力分析

甘肃省高产农区农业自然环境资源时空组合特点及其光合潜力、光温潜力、光温水潜力和光温水土潜力的分布变化规律分析结果表明:甘肃省光能资源丰富;热量资源偏低且垂直和水平差异显著;水资源贫乏;土地质量普遍偏低.光合潜力河西区可达16 468.5 kg/hm2,陇南和陇东次之,陇中较其他各地差;光温潜力河西区为10 452.0 kg/hm2,陇南为7 671.0 kg/hm2,河西和陇中地区光热同步,光温潜力达光合潜力的66.62%和65.95%,陇东和陇南地区为57.49%和53.06%;在河西绿洲灌区,光温水潜力和光温水土潜力均最高,分别占光温潜力和光温水潜力的88.0%和95.7%以上;陇中、陇东和陇南区较低,光温水土潜力仅达光温水潜力的60%～67.4%.     

气象因子对黄土高原间套作豌豆和春小麦叶片水势的影响

在甘肃省农业科学院会宁农业试验站,对春小麦和豌豆间套作模式下,不同气象因子对春小麦和豌豆叶水势的影响进行了田间对比观测。结果表明:在半干旱地区,春小麦和豌豆的叶水势与气象因子的关系在不同生育期的表达式不同,与大气温度呈线性关系,与太阳辐射、大气相对湿度、大气水势均呈二次方程模型,与综合气象因子也呈良好的线性关系。不同气象因子对作物叶水势影响的通径分析表明,影响春小麦叶水势日变化作用最强的气象因子是大气水势,其次是大气相对湿度、大气温度和太阳辐射。大气相对湿度、大气温度和太阳辐射对春小麦叶水势日变化的直接影响小于它们通过大气水势的间接影响。对豌豆叶水势日变化直接影响最大的气象因子是大气温度,其次是大气水势、太阳辐射和大气相对湿度。大气水势、太阳辐射和大气相对湿度的直接通径系数均小于各自通过大气温度的间接通径系数,这三者对豌豆叶水势日变化的直接影响小于它们通过大气温度的间接影响。     

西藏参考作物蒸散量时空变化特征与影响因素

为深入认识西藏参考作物蒸散量(ET_0)的变化特征,采用联合国粮农组织1998年推荐的Penman-Monteith公式计算西藏37个气象站点32 a(1981—2012年)的逐日ET_0,通过联合国防治荒漠化公约提出的全球干旱指数(UNEP)进行气候评价,利用空间插值及Mann-Kendall趋势检验法对西藏及各气候区ET_0时空变化特征进行分析,并通过偏相关分析法对其主要影响因素进行探讨,结果表明:西藏共分为特干旱、干旱、半干旱、干旱半湿润、湿润半湿润和湿润气候区,主要为半干旱气候区。近32 a参考作物蒸散量整体呈减小趋势,变化趋势为-1.508 mm·a~(-1),可将32 a分为3个时段,1981—1989年处于高蒸散阶段,1989年后处于低蒸散阶段,2005年起又持续回升。西藏西部到东部,年际ET_0呈减小趋势。各气候区气象因子的影响基本符合平均气温日照时数平均风速相对湿度,且平均气温、日照时数及平均风速在干旱区的影响较湿润区更为显著。     

甘肃省冬小麦干旱灾害风险评估及其区划

为提高西北旱作冬小麦干旱风险管理水平,选用甘肃省41个气象站1971—2016年逐日常规气象观测资料及甘肃省冬小麦农业生产相关资料,基于自然灾害风险理论,从危险性、暴露性、脆弱性、防灾能力4个因子出发,建立了甘肃省冬小麦干旱灾害风险评估模型,并用Arc GIS对甘肃省冬小麦进行干旱风险区划。结果表明:甘肃省冬小麦全生育期干旱高危险区和次高危险区主要位于陇中北部、陇东北部和陇南南部;高暴露区和次高暴露区集中在陇东和陇南地区;高脆弱区和次高脆弱区主要位于陇东大部;次低防灾能力区和低防灾能力区位于陇东大部和陇南北部。甘肃省冬小麦高风险区分布于庆阳市北部和陇南市南部,次高风险区和中度风险区主要位于陇东大部、陇中北部和天水市北部,省内其余冬小麦区属于次低和低风险区。该研究成果将为甘肃冬小麦防灾减灾及可持续发展提供一定理论依据。     

气象因子对晚稻细菌性条斑病发病程度的影响

应用通径分析原理,对1989～2006年化州市晚稻细菌性条斑病发生的历史资料进行分析,明确在气象因子中,雨日是影响该病发病程度的主导因子,平均相对湿度、降雨量、平均气温、日照时数等对该病发病程度的直接作用较小,但通过雨日发挥明显的间接作用。     

甘肃油菜产量时空特征及其对气候变暖的响应

利用1981～2000年20 a甘肃省64县区油菜产量和生长期(4～10月)气温资料,主要采用REOF和小波分析等方法,分析油菜产量的地区差异和受气候变暖的影响.结果表明:甘肃油菜产量存在4个特征区,印河西走廊高产不稳定区,河西东部及陇东地区和陇中产量不稳定区,甘南高原等甘肃南部边缘低产稳定区.产量变化以2～4 a左右的年际振荡为主,5 a周期大多对应极值产量.气温异常偏高(低)相应的河西走廊产量异常偏歉(丰),甘南等甘肃南部边缘地区产量随气温的升高(降低)而升高(降低),这些地区油菜产量对气候变暖响应显著;甘肃黄土高原地区对气候变暖响应不太明显.     

甘肃省风速变化趋势分析

近年来,我国风能资源开发增长迅速,甘肃省风能资源储量在全国名列前茅。为降低风电企业投资的风险,需要对当地多年的风速状况进行评估。文中选用甘肃省79个台站1976年至2010年35年的风速资料,30个台站的历史沿革资料,采用T检验法、SNHT(Standard Normal Homogeneity Test)方法及经验正交分解方法(EOF)对甘肃省风速资料进行分析。T检验表明,甘肃省79个站35年的风速资料有3.98%的存在非均一性;资料分析结果表明,甘肃各地风速除陇中及定西部分地区略有上升外,大部分地区风速呈下降趋势,包括风能资源丰富的地区,且下降趋势较明显,其中河西祁连山区风速下降在0.13m/s.10a～0.26m/s.10a之间,河西东部地形平坦区域风速下降在0.13m/s.10a以下;陇南及陇东大部分地区风速下降在0.13m/s.10a以下。甘肃台站风速每十年变化量与本站1976～2010年平均风速比较结果显示:除陇中及定西部分地区风速略有上升,每十年上升在5%～10%之间外,河西祁连山区风速每十年下降在5%～15%之间,河西东部地形平坦区域风速每十年下降在5%以下;陇南及陇东大部分地区风速每十年下降在5%～10%之间。这是今后风电场投资必须要考虑与防范的风险因素之一。     

1961～2010年甘肃合作地区草地潜在蒸散量及地表湿润度变化特征

为了对青藏高原东北部边坡地带潜在蒸散量和地表湿润度的变化进行研究,利用甘肃省合作市气象站1961～2010年的地面气象观测资料,根据Penman-Monteith模型计算了合作地区草地潜在蒸散量,发现合作地区年潜在蒸散量呈明显上升的趋势,上升趋势为13.0mm/10a;地表湿润度以-0.02/10a的趋势减小,出现了明显的暖干化趋势。温度升高和相对湿度下降是造成合作地区草地潜在蒸散量上升的主要气候影响因子,同时日照时数增加、降水量减少和风速增大对合作地区草地潜在蒸散量上升也有重要影响。     

Richtlinien der Verbände des ökologischen Landbaus zum Vorratsschutz

Zusammenfassung Verbände des ökologischen Landbaus wie z. B. Bioland, Gäa, Demeter; Naturland, Ernte für das Leben oder Bio Suisse beschränken ihre Mitglieder bei der Wahl von Vorratsschutzmaßnahmen. Vorrang besitzen Maßnahmen zur Vermeidung von Schädlingen gegenüber Bekämpfungsmaßnahmen. Fallen müssen zur Befallsüberwachung eingesetzt werden, um einen Befall durch Vorratsschädlinge frühzeitig zu erkennen. Diese Maßnahmen sollen den weitgehenden Verzicht auf chemisch-synthetische Mittel ermöglichen. In diesem Beitrag werden die Empfehlungen der Verbände mit den derzeit verfügbaren chemischen Mitteln für den Vorratsschutz abgeglichen. Erfahrung in der praktischen Umsetzung von physikalischen und biologischen Verfahren werden diskutiert und Defizite bei der Befallsüberwachung und Bekämpfung beschrieben.     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Development of protocols for detection of Colletotrichum acutatum and monitoring of strawberry anthracnose using real-time PCR

Real-time PCR (TaqMan®) assays were developed for the specific detection and discrimination of Colletotrichum spp., C. acutatum and C. gloeosporioides causing anthracnose in strawberry using the most divergent area of the internal transcribed spacers (ITS1 and ITS2) and 5·8S ribosomal RNA (rRNA) gene region. The specificity of the new assays was tested using DNA from six species of Colletotrichum and nine fungal species commonly found associated with strawberry material, and additionally by comparing the sequences with those from databases using a blast search. The sequences only showed identity with homologous sequences from the desired target organisms. The new assays were 10–100 times more sensitive than conventional PCR methods previously published for the diagnosis of strawberry anthracnose. When real-time PCR was compared with ELISA methods, PCR improved the sensitivity of the identification by obtaining positive results for samples of strawberry plant material that tested negative with ELISA. The development of C. acutatum was monitored using artificially infected strawberry crowns from two strawberry cultivars (Camarosa and Ventana) and a real-time PCR assay specific for this species between January and June 2006. The amount of C. acutatum detected using real-time PCR varied significantly by month ( P  < 0·001), but not by cultivar ( P  = 0·394). The new assays were shown to be useful tools for rapid detection and identification of these pathogens and to allow rapid and accurate assessment of the casual agents of anthracnose in strawberry.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.