混交林纯林中毛竹出笋退笋特性研究

应用出笋量的逻辑斯谛 ( L ogistic)模型研究了出笋量随时间增长的变化规律 ,结果表明 :出笋前期 (前 1 0 d)出笋数占总数的 1 5%左右 ,出笋中期 (第 1 0～ 2 0天 )占 75%,出笋末期 (第2 0天以后 )占 1 0 %;对退笋特征的观察及其规律的研究得出 :出笋前后期退笋数量少但退笋率高 ,而出笋中期退笋数量多但退笋率低 .小于 1 0 cm的浅鞭竹笋多属退化笋 .纯林中的出笋比混交林中的出笋持续天数短 ,退笋率高 ,为此混交林更有利于竹笋的生长 .出笋退笋规律可用来指导生产 ,为留养和挖取竹笋数量提供依据     

Influence of physiological ageing of seed potatoes on yield and earliness

Summary Ageing seed potatoes at ambient temperatures after long storage (26 weeks) at 2 °C affected rate of plant emergence and yields of three potato cultivars in Cyprus. Sprout growth at ambient increased until planting, and was bigger in cv. Spunta than in cv. Arran Banner and cv. Cara. Four weeks after planting the rate of emergence was higher in physiologically younger seed; total emergence was not affected but average yields were reduced by ageing. Early yields were less affected but final yields were significantly reduced by ageing; these effects were moro pronounced in Spunta and Arran Banner, early and medium maturity cultivars respectively than in Cara, a late maturity cultivar. Ageing of seed at ambient temperature was rapid and removing seed to ambient for more than 3 weeks before planting to save storage costs adversely affected final yields.

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Zusammenfassung Eine nach verl?ngerter Lagerung bei 2 °C erfolgte Alterung der Saatkartoffeln bis zu 9 Wochen in der Umgebungstemperatur beeinflusste bei den Sorten Arran Banner, Spunta und Cara das Auflaufen der Pflanzen und die Ertr?ge. Das Keimwachstum wurde nach überführung aus dem Kaltlager in die Umgebungstemperatur bis zum Auspflanzen nicht unterbrochen; die Keime von Spunta waren l?nger als diejenigen von Arran Banner und Cara (Abb. 1). Bei physiologisch ?lterem Saatgut liefen die Pflanzen schneller auf als bei jüngerem (Tab. 1). Fünf Wochen nach dem Auspflanzen war die Auflaufrate in allen Behandlungen ?hnlich und gr?sser als 80 % (Tab. 1). Drei Wochen nach dem Auspflanzen war die Auflaufrate der Pflanzen durch die Alterung erh?ht. Die Zwischen- und Endertr?ge wurden durch die Alterung signifikant beeinflusst Saatgut, das l?nger als 3 Wochen in der Umgebungstemperatur gehalten wurde, erbrachte geringere Zwischen- und Endertr?ge. Die Frühertr?ge wurden durch die Alterungsbehandlungen weniger beeinflusst (Tabellen 2, 3 und 4). Die Saatkartoffeln alterten schneller nach überführung in die Umgebungstemperatur und ein Verbleiben des Saatgutes in der Umgebungstemperatur für mehr als 3 Wochen führt zu geringeren Ertr?gen. Wenn auch der Alterungsprozess w?hrend der Kaltlagerung fortschreitet, ist eine Verl?ngerung der Kaltlagerzeit wünschenswert, um dann das Saatgut in die Umgebungstemperatur zu übertragen und dadurch Lagerkosten zu sparen.

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Résumé Le vieillissement physiologique de plants de pomme de terre obtenu par la conservation à la température ambiante pendant des durées de 0 à 9 semaines après un maintien prolongé à 2 °C, affecte la levée et le rendement des variétés Arran Banner, Spunta et Cara. Après que les tubercules aient été sortis de chambre froide, la croissance des germes se poursuit jusqu'à la plantation. Les germes de Spunta sont plus longs que ceux d'Arran Banner et de Cara (fig. 1). La levée des plants est plus rapide chez ceux physiologiquement vieux que chez ceux physiologiquement jeunes (tableau 1). Cinq semaines après la plantation, le taux de levée est identique dans tous les traitements et dépasse 80% (tableau 1). La levée des plants trois semaines après la plantation est accrue par le vieillissement. Les rendements intermédiaires et finaux sont significativement affectés par le vieillissement. Les plants placés pendant plus de 3 semaines à température ambiante donnent de plus faibles rendements intermédiaires et finaux. La précocité des rendements est moins affectée par les traitements de vieillissement (tableaux 2, 3 et 4). Les plants vieillissent plus rapidement à la température ambiante et ceux conservés plus de trois semaines dans ces conditions donnent une réduction de rendement. Toutefois, le processus de vieillissement se poursuit également durant la période de conservation au froid aussi l'extension de la durée de cette période est préférable à cette de la mise à température ambiante lorsqu'elle est réalisée dans un but d'économie.

     

Which model species for weed seedbank and emergence studies? A review

Models predicting the effects of cropping systems on weed demography are important tools for testing new rules for integrated weed management that may reduce the use of herbicides and preserve the biodiversity of agro-ecosystems. Such models already exist for a few species and should now be extended to a larger flora, in order to predict and understand the effects of agricultural practices on the evolution of weed communities. This review analysed the literature from 1973 to 2006, focusing on 45 species, to identify past reasons for choosing particular species when modelling the effects of cropping systems on the processes leading to seedling emergence. The frequency or harmfulness of the species were the main reason for studying them. It appears that the studied species were mainly autumn-emerging in north-western Europe cropping systems and summer-emerging in North America; the effects of deep soil tillage were studied mainly in Europe, as simplified sowing techniques are more often practised in North America. A voluminous literature exists on seed persistence in the soil, dormancy, germination and emergence, but rarely with the attempt of establishing generic relationships between species characteristics and model parameters. Until now, such an approach has been mostly developed in ecological studies. Taxa, as well as ecological preferences, seed size and the relationships of these characteristics with weed emergence model parameters should be considered when selecting a range of species for multi-specific modelling purposes.     

福建省重大林业有害生物灾害及应急管理对策

划分了福建省重大林业有害生物灾害类型,总结了重大林业有害生物灾害发生特点,并针对灾害发生形势和防控存在问题,阐述了应急管理的必要性,综合提出应急管理的对策。     

不同基肥混合施用对杉木种子出苗影响的研究

采用正交试验方法 ,对过磷酸钙、菜籽饼粉及复合肥不同的施肥水平影响杉木种子出苗情况进行了效果对比试验。结果表明 :混合施用过磷酸钙与复合肥的处理组合均能促进杉木种子出苗 ,最佳组合为每hm2 混合施用 75 0kg过磷酸钙及 375kg复合肥 ,出苗率比对照高出 30 3%。     

Use of monthly collected milk yields for the detection of the emergence of the 2007 French BTV epizootic

Two culicoides-borne diseases, Bluetongue (BTV) and Schmallenberg, have emerged in the European cattle population since 2006. Other diseases transmitted by these vectors could emerge. This justifies the development of syndromic surveillance programs whereby one or several indicators would be routinely monitored for the early detection of emerging diseases. The aim of this study was to evaluate milk yield from milk recording in dairy cattle as an indicator to be included in an emerging disease surveillance system. It was hypothesized that emergences would result in episodes of low milk production clustered in space and time. The 2007 BTV epizootic in France was used as a case study. Because it had already emerged in neighbouring countries, the disease emergence was expected and notification was mandatory. Herd-test-day milk productions were predicted for the entire country for 2006 and 2007 from herd historical data using linear mixed models. The differences between observed and predicted milk productions were averaged per week and per municipality and used as input for a space-time prospective scan statistic. Log likelihood ratios (LLR) associated with clusters were used to define alarms. The threshold chosen was a trade-off between detection timeliness and the number of false alarms per week. The first four BTV notifications occurred on the 12th (two notifications), 13th and 27th of July 2007. The 12th of July was considered to be the date of emergence. Alarms occurring before the 1st of March 2007 were considered to be false alarms. Using an LLR of 50, there were an average of 1.7 false alarms per week and the BTV emergence was detected seven weeks after emergence. Using an LLR of 100, there were an average of 0.8 false alarms per week and the BTV emergence was detected 9 weeks after emergence. Detection may have been delayed because of a discontinuation of milk recording between mid-July and mid-August. The first cluster with an LLR > 100 located in the emergence area was further investigated. A difference between observed and predicted production of >1 kg/cow/day was observed around the time of emergence. However, a difference of equal magnitude was observed during the year preceding the outbreak. Milk production predicted from herd history alone did not allow the detection of the 2007 BTV emergence in France. Further research should be conducted on improving the prediction of test-day milk yield and on combining it with other indicators based on routinely collected data.     

麻楝蛀斑螟成虫的羽化节律及生殖行为

在温度（25±1）℃,光暗周期L：D=14：10（光期06：00开始,20：00结束）,相对湿度RH=75％-80％的条件下,观察了麻楝蛀斑螟成虫的羽化与生殖行为．结果表明：成虫羽化率85．4％,羽化期25d左右;羽化行为主要出现在暗期,日羽化高峰在20：00-23：00,占总羽化量的80．7％;雌、雄比例0．83：1．羽化后第2天达到性成熟,当天羽化的成虫未发生交配;交配发生在进入暗期5-8h,交配持续时间50—200min;随着日龄的增大,交配率降低,交配持续时间增长;交配后第2天开始产卵;雌、雄虫均未发现2次交配现象．交配雌虫平均产卵104粒,卵期7d左右,孵化率84．3％;未交配雌虫平均产卵157粒,孵化率0．交配雌虫和雄虫的平均寿命为3．73和2．93d,未交配雌虫和雄虫的平均寿命为5．87和5．03d．     

不同杀虫处理及播种时期对蒙古栎种子出苗率的影响研究

采用热水杀虫和药剂熏蒸2种不同种子处理方式,及采用随采随播、上冻前播种、层积沙藏后翌年春天播种3种播种方式来研究其对蒙古栎种子出苗率的影响。结果表明不同杀虫处理、播种方式对蒙古栎出苗率的影响有显著差异,种子经过敌敌畏药熏处理后当年9月随采随播出苗率最好,出苗率达87%。     

稗不同出苗时间和密度对机械直播水稻灌浆期根系特性的影响

为探讨机械直播稻田稗最佳防控时间,采用小区试验的方法,以人工除草处理为对照,研究稗不同出苗时间(水稻机械直播后0、7、14、21、28、35 d)和不同密度(1、3、5、7株·m^-2)对机械直播水稻根系特性以及产量的影响。结果表明,稗出苗时间和密度对水稻产量有不同的影响,稗草出苗时间越早或密度越大,水稻减产越多。当稗密度为1株·m^-2时,水稻机械直播后0~35 d出苗的稗均对水稻产量无影响;当稗密度为3、5、7株·m^-2时,在水稻机械直播后21 d内出苗的稗均随其密度增加而显著降低水稻产量,之后出苗的稗对水稻产量无明显影响。同时发现,产量显著降低后水稻的根系总根长、平均根系直径、根干重、根系总吸收面积、根系活跃吸收面积、根系氧化力和玉米素+玉米素核苷含量也均显著降低。上述水稻根系指标的降低可能是机械直播水稻与稗伴生后产量降低的重要原因。本研究为机械直播稻田稗草防控提供了理论依据。     

气象因子对甘蔗种茎出苗率以及苗期生长的影响

为了探明影响广西甘蔗种茎出苗及苗期生长的气象因子,本研究选用2个广西当家甘蔗品种‘新台糖22号’（T22）和‘桂糖42号’（G42）为研究对象,从2—5月开展甘蔗分期播种试验,每半个月播种1期。通过观测每期甘蔗的出苗率、苗期生长状况以及同期的气象因子（降雨量、平均气温）,并对数据进行相关统计分析。结果表明,T22、G42蔗种的出苗率与播种后20 d的累积降雨量呈显著正相关,而与播种后10 d的累积降雨量呈正相关,差异未达显著水平。由播种后20 d的累积降雨量与甘蔗出苗率的对数函数方程进一步显示,为了使甘蔗种茎出苗率达80%以上,甘蔗播种后20 d的累积降雨量要达到75 mm以上;播种后的平均气温、降水量和日照时数与甘蔗苗茎伸长期株高/茎粗相关性达到5%显著性水平以上,进一步逐步回归分析显示,降水量是影响甘蔗茎伸长期株高/茎粗的显著性自变量。推断甘蔗播种后10~20 d的累积降雨量是决定甘蔗出苗的关键气象因子,在甘蔗苗期生长过程中,降雨量对甘蔗生长至关重要,可以通过降雨量预测甘蔗苗期株高/茎粗。鉴于以上研究结果,在广西甘蔗生产过程中,为了提高甘蔗出苗率,要加强甘蔗种植后20 d内的水分管理,在这期间累积降雨量需达到75 mm以上才能达到甘蔗齐苗的目的,甘蔗出苗后也需加强水分管理,利于苗期快速生长,从而提高蔗苗质量。