除草剂对徐州山地林下主要杂草的防除

通过对徐州市林场侧柏人工纯林林下植被进行抽样调查,选取形成林火地面易燃物的主要杂草一年蓬、野燕麦为研究对象,用农达(草甘膦异丙胺盐41%水剂)、MCPA(2甲4氯钠盐13%水剂)、精禾草克(精喹禾灵5%乳油)3种防除效率较高的除草剂进行试验。结果表明,农达和MCPA不同浓度混合溶液具很好的防除效果。从生态环境、防除效果和经济成本等因素综合考虑,200倍农达稀释液与200倍MPCA稀释液的混合液对一年蓬和野燕麦防除效果最佳,可应用在森林防火隔离带的建设中。     

竹林化学除草药效试验

用31．6％兴华除草剂和41％农达(草甘膦)水剂的不同剂量对竹林化学除草的药效试验表明，其防除效果均是随着用药量的增加而增强，不同剂量的防效差异达到极显著的水平。竹林化学除草比人工抚育节约费用，且对竹林安全，经济、生态效益显著。     

中东海枣苗圃地化学除草试验

在使用多种除草剂初步试验的基础上,采用10%草甘膦水剂进行随机区组排列试验,结果表明:10%草甘膦水剂能有效防除苗圃地一年生杂草,剂量为1.95ml·m-2时,防除阔叶杂草效果达97.5%,剂量为2.25ml·m-2时,防除窄叶杂草的效果达90.9%。10%草甘膦水剂不同剂量之间防除杂草效果的差异极显著,防除阔叶、窄叶杂草的防除效果之间的差异极显著。以2.25ml·m-2的剂量计,化学除草成本为0.01元·m-2,与人工除草相比,该化学除草成本是人工挖草的7.2%,人工铲草的23.8%。为保护好苗木,在喷除草剂时应做好幼苗的套袋保护工作,并根据杂草大小等情况适当调整剂量,从而达到理想的剂量与成本组合。     

“快招”等3种除草剂在针叶树育苗上的应用试验

应用10%草甘膦水剂、快招(41%草甘膦异丙胺盐水剂)、20%克无踪水剂等3种除草剂对青海云杉苗圃地开展了除草试验。结果表明:3种除草剂中以"快招"效果最好,浓度以10 mg·g-1为宜。在晴朗无风的中午,采取定向喷雾,对青海云杉苗圃地杂草有较好的防除效果;和人工除草相比较,使用"快招"除草可节省费用73.3%。     

杉木、马尾松幼林中以五节芒为主的杂草防除试验

通过采用不同药剂对杉木、马尾松幼林中以五节芒为主的杂草防除试验,结果表明:森泰能有效地灭除杉木、马尾松林的多年生恶性杂草五节芒、苦竹、刚竹、芒萁骨等;以草甘膦为主剂,Goal、Oust为辅剂的草甘膦混剂也能灭除五节芒等杂草,防除效果分别达到95%和92%以上。化学除草比人工除草减少用工56.1%~61%,同时为幼树生长创造良好的环境。     

41%农达除草剂在毛竹山上试用初探

用美国生产的除草剂41％农达进行除草试验,其除草效果优于草甘膦,且能够有效地除灭毛竹林中的乔灌木、藤本植物和其它杂草。     

火炬树防控的初步研究

为研究化学药剂和人工方式对火炬树的防除效果,实验比较了10%草甘磷水剂和41%农达的不同浓度、人工砍除地上部分和连根挖除的方式对火炬树的防除效果.结果表明:农达药剂浓度处理Ⅱ5在处理第16d时,毒害率和枯死率均达100%.处理Ⅱ4和Ⅱ6防除效果也在第31d时达到99%和98%.运用人工砍除地上部分和连根挖除方式对火炬树进行防除,由于不能完全挖除火炬树根系,一段时间后仍有一定量根蘖幼苗萌发.结合防除效果和防除成本考虑,41%农达药剂浓度0.3mL·m-2(Ⅱ4)时,其防除效果达99%,可在生产中加以应用推广.     

25%阿森呐水剂防除果园地杂草试验

试验表明，用25％阿森呐(ARSENAL)水剂750～1000ml／hm^2(有效成分)于杂草3～5叶茎叶喷雾，不仅对出苗的杂草有优异的防除效果，而且能有效地控制杂草出苗。施药后60d的防除效果达97.5％～100％，施药后90d的防除效果仍达85．5％～91．7％，明显长于常规药剂41％农达水剂20～30d的持效期。     

油茶幼林中恶性杂草的化学防除试验

试验表明:森泰能有效地灭除油茶幼林地的多年生恶性杂草五节芒、黄茅草、苦竹、刚竹、芒萁骨等;以草甘膦为主剂,Goal、Oust为辅剂的草甘膦混剂也能灭除五节芒等杂草,防除效果分别达到95%和92%以上。化学除草比人工除草减少用工56.1%~61%,同时为幼树生长创造良好的环境。     

香榧苗圃地除草剂筛选试验

为提高香榧苗圃地杂草的防除效果,保护苗木,降低用工成本,选用普通市售除草剂,采用随机区组和正交设计筛选对香榧苗木无害且有效的除草荆单荆和组合.结果表明:(1)推荐剂量范围内不同除草剂对香榧苗圃地杂草都有一定的防除效果,药后第28天的株防效在57.46%～74.63%之间.果尔、百草枯的株防效较好,时效较长,可以选用;草甘膦的短时株防效最高,但时效短;精稳杀得起效较慢.(2)不同浓度除草剂混用后的除草效果比单剂好,药后第28天的株防效在84.32%～94.74%,筛选出的24%果尔乳油(1 050 mL/hm2)+10%草甘膦水剂(16 500 mL/hm2)+15%精稳杀得乳油(450 mL/hm2)复配剂除草效果最佳.(3)香榧苗圃地使用除草剂对苗木生长无影响,而且工效高,伤苗少,成本低,相对人工除草降低1 950 元/hm2以上.     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.